]> git.djapps.eu Git - pkg/ggml/sources/ggml/commitdiff
sam : support box prompt (#1206)
authorTaylor <redacted>
Thu, 8 May 2025 15:56:59 +0000 (10:56 -0500)
committerGitHub <redacted>
Thu, 8 May 2025 15:56:59 +0000 (18:56 +0300)
* SAM: parse box prompt

* support box prompt

* sam: rename main.cpp to sam.cpp

* pass sam_prompt as const &

* support single mask output (default multimask)

* Update examples/sam/sam.cpp

Co-authored-by: Georgi Gerganov <redacted>
* Update examples/sam/sam.cpp

Co-authored-by: Georgi Gerganov <redacted>
* Update examples/sam/sam.cpp

Co-authored-by: Georgi Gerganov <redacted>
* Update examples/sam/sam.cpp

Co-authored-by: Georgi Gerganov <redacted>
* Update examples/sam/sam.cpp

Co-authored-by: Georgi Gerganov <redacted>
* removed debug print

* test sam example: box prompt and single mask output

---------

Co-authored-by: Georgi Gerganov <redacted>
ci/run.sh
examples/sam/CMakeLists.txt
examples/sam/main.cpp [deleted file]
examples/sam/sam.cpp [new file with mode: 0644]

index 1738aac2a0c69aac86b55771aabadf74fc46ba78..66f15cd7eb506b6f89498d244cd0be7b6618758c 100644 (file)
--- a/ci/run.sh
+++ b/ci/run.sh
@@ -254,10 +254,16 @@ function gg_run_sam {
 
     python3 ../examples/sam/convert-pth-to-ggml.py ${path_models}/sam_vit_b_01ec64.pth ${path_models}/ 1
 
+    # Test default parameters
     (time ./bin/sam -m ${model_f16} -i ${img_0} ) 2>&1 | tee -a $OUT/${ci}-main.log
-
+    grep -q "point prompt" $OUT/${ci}-main.log
     grep -q "bbox (371, 436), (144, 168)" $OUT/${ci}-main.log
 
+    # Test box prompt and single mask output
+    (time ./bin/sam -m ${model_f16} -i ${img_0} -b 368,144,441,173 -sm) 2>&1 | tee -a $OUT/${ci}-main.log
+    grep -q "box prompt" $OUT/${ci}-main.log
+    grep -q "bbox (370, 439), (144, 169)" $OUT/${ci}-main.log
+
     set +e
 }
 
index fa302bb402708471dbbe0b11a88e5de3ca4c1aa7..5033618a3cd243efc8f6b6a78d4c58d3992acb16 100644 (file)
@@ -2,7 +2,7 @@
 # sam
 
 set(TEST_TARGET sam)
-add_executable(${TEST_TARGET} main.cpp)
+add_executable(${TEST_TARGET} sam.cpp)
 target_link_libraries(${TEST_TARGET} PRIVATE ggml common)
 
 #
diff --git a/examples/sam/main.cpp b/examples/sam/main.cpp
deleted file mode 100644 (file)
index eeb7e5c..0000000
+++ /dev/null
@@ -1,2233 +0,0 @@
-#define _USE_MATH_DEFINES // for M_PI
-#define _CRT_SECURE_NO_DEPRECATE // Disables ridiculous "unsafe" warnigns on Windows
-
-#include "ggml.h"
-#include "ggml-cpu.h"
-#include "ggml-alloc.h"
-#include "ggml-backend.h"
-#define STB_IMAGE_IMPLEMENTATION
-#include "stb_image.h"
-#define STB_IMAGE_WRITE_IMPLEMENTATION
-#include "stb_image_write.h"
-
-#include <cassert>
-#include <cmath>
-#include <cstddef>
-#include <cstdio>
-#include <cstring>
-#include <fstream>
-#include <map>
-#include <string>
-#include <vector>
-#include <thread>
-#include <cinttypes>
-
-#if defined(_MSC_VER)
-#pragma warning(disable: 4244 4267) // possible loss of data
-#endif
-
-// default hparams (ViT-B SAM)
-struct sam_hparams {
-    int32_t n_enc_state               = 768;
-    int32_t n_enc_layer               = 12;
-    int32_t n_enc_head                = 12;
-    int32_t n_enc_out_chans           = 256;
-    int32_t n_pt_embd                 = 4;
-    int32_t n_dec_heads               = 8;
-    int32_t ftype                     = 1;
-    float   mask_threshold            = 0.f;
-    float   iou_threshold             = 0.88f;
-    float   stability_score_threshold = 0.95f;
-    float   stability_score_offset    = 1.0f;
-    float   eps                       = 1e-6f;
-    float   eps_decoder_transformer   = 1e-5f;
-
-    int32_t n_enc_head_dim() const { return n_enc_state / n_enc_head; }
-    int32_t n_img_size()     const { return 1024; }
-    int32_t n_window_size()  const { return 14; }
-    int32_t n_patch_size()   const { return 16; }
-    int32_t n_img_embd()     const { return n_img_size() / n_patch_size(); }
-
-    std::vector<int32_t> global_attn_indices() const {
-        switch (n_enc_state) {
-            case  768: return {  2,  5,  8, 11 };
-            case 1024: return {  5, 11, 17, 23 };
-            case 1280: return {  7, 15, 23, 31 };
-            default:
-                {
-                    fprintf(stderr, "%s: unsupported n_enc_state = %d\n", __func__, n_enc_state);
-                } break;
-        };
-
-        return {};
-    }
-
-    bool is_global_attn(int32_t layer) const {
-        const auto indices = global_attn_indices();
-
-        for (const auto & idx : indices) {
-            if (layer == idx) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-};
-
-struct sam_layer_enc {
-    struct ggml_tensor * norm1_w;
-    struct ggml_tensor * norm1_b;
-
-    struct ggml_tensor * rel_pos_w;
-    struct ggml_tensor * rel_pos_h;
-
-    struct ggml_tensor * qkv_w;
-    struct ggml_tensor * qkv_b;
-
-    struct ggml_tensor * proj_w;
-    struct ggml_tensor * proj_b;
-
-    struct ggml_tensor * norm2_w;
-    struct ggml_tensor * norm2_b;
-
-    struct ggml_tensor * mlp_lin1_w;
-    struct ggml_tensor * mlp_lin1_b;
-
-    struct ggml_tensor * mlp_lin2_w;
-    struct ggml_tensor * mlp_lin2_b;
-};
-
-struct sam_encoder_image {
-    struct ggml_tensor * pe;
-
-    struct ggml_tensor * proj_w;
-    struct ggml_tensor * proj_b;
-
-    struct ggml_tensor * neck_conv_0;
-    struct ggml_tensor * neck_norm_0_w;
-    struct ggml_tensor * neck_norm_0_b;
-    struct ggml_tensor * neck_conv_1;
-    struct ggml_tensor * neck_norm_1_w;
-    struct ggml_tensor * neck_norm_1_b;
-
-    std::vector<sam_layer_enc> layers;
-};
-
-struct sam_encoder_prompt {
-    struct ggml_tensor * pe;
-
-    struct ggml_tensor * not_a_pt_embd_w;
-    std::vector<struct ggml_tensor *> pt_embd;
-
-    struct ggml_tensor * no_mask_embd_w;
-    //std::vector<struct ggml_tensor *> mask_down_w;
-    //std::vector<struct ggml_tensor *> mask_down_b;
-};
-
-struct  sam_layer_dec_transformer_attn {
-    // q_proj
-    struct ggml_tensor * q_w;
-    struct ggml_tensor * q_b;
-
-    // k_proj
-    struct ggml_tensor * k_w;
-    struct ggml_tensor * k_b;
-
-    // v_proj
-    struct ggml_tensor * v_w;
-    struct ggml_tensor * v_b;
-
-    // out_proj
-    struct ggml_tensor * out_w;
-    struct ggml_tensor * out_b;
-};
-
-struct sam_layer_dec_transformer {
-    sam_layer_dec_transformer_attn self_attn;
-
-    // norm1
-    struct ggml_tensor * norm1_w;
-    struct ggml_tensor * norm1_b;
-
-    sam_layer_dec_transformer_attn cross_attn_token_to_img;
-
-    // norm2
-    struct ggml_tensor * norm2_w;
-    struct ggml_tensor * norm2_b;
-
-    // mlp.lin1
-    struct ggml_tensor * mlp_lin1_w;
-    struct ggml_tensor * mlp_lin1_b;
-
-    // mlp.lin2
-    struct ggml_tensor * mlp_lin2_w;
-    struct ggml_tensor * mlp_lin2_b;
-
-    // norm3
-    struct ggml_tensor * norm3_w;
-    struct ggml_tensor * norm3_b;
-
-    // norm4
-    struct ggml_tensor * norm4_w;
-    struct ggml_tensor * norm4_b;
-
-    sam_layer_dec_transformer_attn cross_attn_img_to_token;
-};
-
-struct sam_layer_dec_output_hypernet_mlps {
-    // mlps_*.layers.0
-    struct ggml_tensor * w_0;
-    struct ggml_tensor * b_0;
-
-    // mlps_*.layers.1
-    struct ggml_tensor * w_1;
-    struct ggml_tensor * b_1;
-
-    // mlps_*.layers.2
-    struct ggml_tensor * w_2;
-    struct ggml_tensor * b_2;
-};
-
-struct sam_decoder_mask {
-    std::vector<sam_layer_dec_transformer> transformer_layers;
-
-    // trasnformer.final_attn_token_to_image
-    sam_layer_dec_transformer_attn transformer_final_attn_token_to_img;
-
-    // transformer.norm_final
-    struct ggml_tensor * transformer_norm_final_w;
-    struct ggml_tensor * transformer_norm_final_b;
-
-    // output_upscaling.0
-    struct ggml_tensor * output_upscaling_0_w;
-    struct ggml_tensor * output_upscaling_0_b;
-
-    // output_upscaling.1
-    struct ggml_tensor * output_upscaling_1_w;
-    struct ggml_tensor * output_upscaling_1_b;
-
-    // output_upscaling.3
-    struct ggml_tensor * output_upscaling_3_w;
-    struct ggml_tensor * output_upscaling_3_b;
-
-    // output_hypernetworks_mlps
-    std::vector<sam_layer_dec_output_hypernet_mlps> output_hypernet_mlps;
-
-    // iou_prediction_head.0
-    struct ggml_tensor * iou_prediction_head_0_w;
-    struct ggml_tensor * iou_prediction_head_0_b;
-
-    // iou_prediction_head.1
-    struct ggml_tensor * iou_prediction_head_1_w;
-    struct ggml_tensor * iou_prediction_head_1_b;
-
-    // iou_prediction_head.2
-    struct ggml_tensor * iou_prediction_head_2_w;
-    struct ggml_tensor * iou_prediction_head_2_b;
-
-    // iou_token.weight
-    struct ggml_tensor * iou_token_w;
-
-    // mask_tokens.weight
-    struct ggml_tensor * mask_tokens_w;
-};
-
-
-struct sam_state {
-    struct ggml_tensor * embd_img;
-
-    struct ggml_tensor * low_res_masks;
-    struct ggml_tensor * iou_predictions;
-
-    //struct ggml_tensor * tmp_save = {};
-
-    struct ggml_context * ctx;
-
-    // buffer for `ggml_graph_plan.work_data`
-    std::vector<uint8_t> work_buffer;
-    // buffers to evaluate the model
-    std::vector<uint8_t> buf_compute_img_enc;
-
-    std::vector<uint8_t> buf_compute_fast;
-
-    ggml_gallocr_t       allocr = {};
-};
-
-// void save_tensor(sam_state& state, struct ggml_tensor * t, struct ggml_cgraph * gf) {
-//     if (!state.tmp_save) {
-//         state.tmp_save = ggml_new_tensor(state.ctx, t->type, t->n_dims, t->ne);
-//     }
-//     struct ggml_tensor * tmp0 = ggml_cpy(state.ctx, t, state.tmp_save);
-//     ggml_build_forward_expand(gf, tmp0);
-// }
-
-struct sam_model {
-    sam_hparams hparams;
-
-    sam_encoder_image  enc_img;
-    sam_encoder_prompt enc_prompt;
-    sam_decoder_mask   dec;
-
-    //
-    struct ggml_context * ctx;
-    std::map<std::string, struct ggml_tensor *> tensors;
-};
-
-struct sam_point {
-    float x;
-    float y;
-};
-
-// RGB uint8 image
-struct sam_image_u8 {
-    int nx;
-    int ny;
-
-    std::vector<uint8_t> data;
-};
-
-// RGB float32 image
-// Memory layout: RGBRGBRGB...
-struct sam_image_f32 {
-    int nx;
-    int ny;
-
-    std::vector<float> data;
-};
-
-struct sam_params {
-    int32_t seed      = -1; // RNG seed
-    int32_t n_threads = std::min(4, (int32_t) std::thread::hardware_concurrency());
-
-    std::string model     = "models/sam-vit-b/ggml-model-f16.bin"; // model path
-    std::string fname_inp = "img.jpg";
-    std::string fname_out = "img.out";
-    float   mask_threshold            = 0.f;
-    float   iou_threshold             = 0.88f;
-    float   stability_score_threshold = 0.95f;
-    float   stability_score_offset    = 1.0f;
-    float   eps                       = 1e-6f;
-    float   eps_decoder_transformer   = 1e-5f;
-    sam_point pt = { 414.375f, 162.796875f, };
-};
-
-void print_t_f32(const char* title, struct ggml_tensor * t, int n = 10) {
-    printf("%s\n", title);
-    float * data = (float *)t->data;
-    printf("dims: % " PRId64 " % " PRId64 " % " PRId64 " % " PRId64 " f32\n", t->ne[0], t->ne[1], t->ne[2], t->ne[3]);
-    printf("First & Last %d elements:\n", n);
-    for (int i = 0; i < std::min((int) (t->ne[0]*t->ne[1]), n); i++) {
-        printf("%.5f ", data[i]);
-        if (i != 0 && i % t->ne[0] == 0) {
-            printf("\n");
-        }
-    }
-    printf("\n");
-    for (int i = 0; i < std::min((int) (t->ne[0]*t->ne[1]), n); i++) {
-        printf("%.5f ", data[ggml_nelements(t) - n + i]);
-        if ((ggml_nelements(t) - n + i) % t->ne[0] == 0) {
-            printf("\n");
-        }
-    }
-    printf("\n");
-    double sum = 0.0;
-    for (int i = 0; i < ggml_nelements(t); i++) {
-        sum += data[i];
-    }
-    printf("sum:  %f\n\n", sum);
-}
-
-static void ggml_disconnect_node_from_graph(ggml_tensor * t) {
-    t->op = GGML_OP_NONE;
-    for (int i = 0; i < GGML_MAX_SRC; i++) {
-        t->src[i] = NULL;
-    }
-}
-
-static void ggml_graph_compute_helper(std::vector<uint8_t> & buf, ggml_cgraph * graph, int n_threads) {
-    struct ggml_cplan plan = ggml_graph_plan(graph, n_threads, nullptr);
-
-    if (plan.work_size > 0) {
-        buf.resize(plan.work_size);
-        plan.work_data = buf.data();
-    }
-
-    ggml_graph_compute(graph, &plan);
-}
-
-static void ggml_sam_sin(struct ggml_tensor * dst , const struct ggml_tensor * src, int ith, int nth, void * userdata) {
-    GGML_ASSERT(userdata == NULL);
-    GGML_ASSERT(ggml_are_same_shape(dst, src));
-    GGML_ASSERT(ggml_is_contiguous(dst));
-    GGML_ASSERT(ggml_is_contiguous(src));
-
-    const float * src_data = ggml_get_data_f32(src);
-    float * dst_data = ggml_get_data_f32(dst);
-
-    const int ne = (int)ggml_nelements(dst);
-    const int dr = (ne + nth - 1) / nth;
-    const int ie0 = dr * ith;
-    const int ie1 = std::min(ie0 + dr, ne);
-
-    for (int i = ie0; i < ie1; ++i) {
-        dst_data[i] = sinf(src_data[i]);
-    }
-}
-
-static void ggml_sam_cos(struct ggml_tensor * dst , const struct ggml_tensor * src, int ith, int nth, void * userdata) {
-    GGML_ASSERT(userdata == NULL);
-    GGML_ASSERT(ggml_are_same_shape(dst, src));
-    GGML_ASSERT(ggml_is_contiguous(dst));
-    GGML_ASSERT(ggml_is_contiguous(src));
-
-    const float * src_data = ggml_get_data_f32(src);
-    float * dst_data = ggml_get_data_f32(dst);
-
-    const int ne = (int)ggml_nelements(dst);
-    const int dr = (ne + nth - 1) / nth;
-    const int ie0 = dr * ith;
-    const int ie1 = std::min(ie0 + dr, ne);
-
-    for (int i = ie0; i < ie1; ++i) {
-        dst_data[i] = cosf(src_data[i]);
-    }
-}
-
-bool sam_image_load_from_file(const std::string & fname, sam_image_u8 & img) {
-    int nx, ny, nc;
-    auto data = stbi_load(fname.c_str(), &nx, &ny, &nc, 3);
-    if (!data) {
-        fprintf(stderr, "%s: failed to load '%s'\n", __func__, fname.c_str());
-        return false;
-    }
-
-    img.nx = nx;
-    img.ny = ny;
-    img.data.resize(nx * ny * 3);
-    memcpy(img.data.data(), data, nx * ny * 3);
-
-    stbi_image_free(data);
-
-    return true;
-}
-
-// ref: https://github.com/facebookresearch/segment-anything/blob/efeab7296ab579d4a261e554eca80faf6b33924a/segment_anything/modeling/sam.py#L164
-// resize largest dimension to 1024
-// normalize: x = (x - mean) / std
-//     mean = [123.675, 116.28, 103.53]
-//     std  = [58.395, 57.12, 57.375]
-//     TODO: why are these hardcoded !?
-// pad to 1024x1024
-// TODO: for some reason, this is not numerically identical to pytorch's interpolation
-bool sam_image_preprocess(const sam_image_u8 & img, sam_image_f32 & res) {
-    const int nx = img.nx;
-    const int ny = img.ny;
-
-    const int nx2 = 1024;
-    const int ny2 = 1024;
-
-    res.nx = nx2;
-    res.ny = ny2;
-    res.data.resize(3*nx2*ny2);
-
-    const float scale = std::max(nx, ny) / 1024.0f;
-
-    fprintf(stderr, "%s: scale = %f\n", __func__, scale);
-
-    const int nx3 = int(nx/scale + 0.5f);
-    const int ny3 = int(ny/scale + 0.5f);
-
-    const float m3[3] = { 123.675f, 116.280f, 103.530f };
-    const float s3[3] = {  58.395f,  57.120f,  57.375f };
-
-    for (int y = 0; y < ny3; y++) {
-        for (int x = 0; x < nx3; x++) {
-            for (int c = 0; c < 3; c++) {
-                // linear interpolation
-                const float sx = (x + 0.5f)*scale - 0.5f;
-                const float sy = (y + 0.5f)*scale - 0.5f;
-
-                const int x0 = std::max(0, (int) std::floor(sx));
-                const int y0 = std::max(0, (int) std::floor(sy));
-
-                const int x1 = std::min(x0 + 1, nx - 1);
-                const int y1 = std::min(y0 + 1, ny - 1);
-
-                const float dx = sx - x0;
-                const float dy = sy - y0;
-
-                const int j00 = 3*(y0*nx + x0) + c;
-                const int j01 = 3*(y0*nx + x1) + c;
-                const int j10 = 3*(y1*nx + x0) + c;
-                const int j11 = 3*(y1*nx + x1) + c;
-
-                const float v00 = img.data[j00];
-                const float v01 = img.data[j01];
-                const float v10 = img.data[j10];
-                const float v11 = img.data[j11];
-
-                const float v0 = v00*(1.0f - dx) + v01*dx;
-                const float v1 = v10*(1.0f - dx) + v11*dx;
-
-                const float v = v0*(1.0f - dy) + v1*dy;
-
-                const uint8_t v2 = std::min(std::max(std::round(v), 0.0f), 255.0f);
-
-                const int i = 3*(y*nx3 + x) + c;
-
-                res.data[i] = (float(v2) - m3[c]) / s3[c];
-            }
-        }
-    }
-
-    return true;
-}
-
-// load the model's weights from a file
-bool sam_model_load(const sam_params & params, sam_model & model) {
-    fprintf(stderr, "%s: loading model from '%s' - please wait ...\n", __func__, params.model.c_str());
-
-    auto fin = std::ifstream(params.model, std::ios::binary);
-    if (!fin) {
-        fprintf(stderr, "%s: failed to open '%s'\n", __func__, params.model.c_str());
-        return false;
-    }
-
-    // verify magic
-    {
-        uint32_t magic;
-        fin.read((char *) &magic, sizeof(magic));
-        if (magic != 0x67676d6c) {
-            fprintf(stderr, "%s: invalid model file '%s' (bad magic)\n", __func__, params.model.c_str());
-            return false;
-        }
-    }
-
-    // load hparams
-    {
-        // Override defaults with user choices
-        model.hparams.mask_threshold            = params.mask_threshold;
-        model.hparams.iou_threshold             = params.iou_threshold;
-        model.hparams.stability_score_threshold = params.stability_score_threshold;
-        model.hparams.stability_score_offset    = params.stability_score_offset;
-        model.hparams.eps                       = params.eps;
-        model.hparams.eps_decoder_transformer   = params.eps_decoder_transformer;
-
-        auto & hparams = model.hparams;
-
-        fin.read((char *) &hparams.n_enc_state,     sizeof(hparams.n_enc_state));
-        fin.read((char *) &hparams.n_enc_layer,     sizeof(hparams.n_enc_layer));
-        fin.read((char *) &hparams.n_enc_head,      sizeof(hparams.n_enc_head));
-        fin.read((char *) &hparams.n_enc_out_chans, sizeof(hparams.n_enc_out_chans));
-        fin.read((char *) &hparams.n_pt_embd,       sizeof(hparams.n_pt_embd));
-        fin.read((char *) &hparams.ftype,           sizeof(hparams.ftype));
-
-        const int32_t qntvr = hparams.ftype / GGML_QNT_VERSION_FACTOR;
-
-        printf("%s: n_enc_state      = %d\n", __func__, hparams.n_enc_state);
-        printf("%s: n_enc_layer      = %d\n", __func__, hparams.n_enc_layer);
-        printf("%s: n_enc_head       = %d\n", __func__, hparams.n_enc_head);
-        printf("%s: n_enc_out_chans  = %d\n", __func__, hparams.n_enc_out_chans);
-        printf("%s: n_pt_embd        = %d\n", __func__, hparams.n_pt_embd);
-        printf("%s: ftype            = %d\n", __func__, hparams.ftype);
-        printf("%s: qntvr            = %d\n", __func__, qntvr);
-
-        hparams.ftype %= GGML_QNT_VERSION_FACTOR;
-
-    }
-
-    // for the big tensors, we have the option to store the data in 16-bit floats or quantized
-    // in order to save memory and also to speed up the computation
-    ggml_type wtype = ggml_ftype_to_ggml_type((ggml_ftype) (model.hparams.ftype));
-    if (wtype == GGML_TYPE_COUNT) {
-        fprintf(stderr, "%s: invalid model file '%s' (bad ftype value %d)\n",
-                __func__, params.model.c_str(), model.hparams.ftype);
-        return false;
-    }
-
-    auto & ctx = model.ctx;
-
-    const size_t ctx_size = [&]() {
-        size_t ctx_size = 0;
-
-        const auto & hparams = model.hparams;
-
-        const int32_t n_enc_state     = hparams.n_enc_state;
-        const int32_t n_enc_layer     = hparams.n_enc_layer;
-        const int32_t n_enc_head_dim  = hparams.n_enc_head_dim();
-        const int32_t n_enc_out_chans = hparams.n_enc_out_chans;
-        const int32_t n_pt_embd       = hparams.n_pt_embd;
-
-        const int32_t n_enc_layer_local  = hparams.global_attn_indices().size();
-        const int32_t n_enc_layer_global = n_enc_layer - n_enc_layer_local;
-
-        const int32_t n_img_embd    = hparams.n_img_embd();
-        const int32_t n_window_size = hparams.n_window_size();
-        const int32_t n_patch_size  = hparams.n_patch_size();
-
-        // image encoder
-        {
-            ctx_size += n_enc_state*n_img_embd*n_img_embd*ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size += n_enc_state*3*n_patch_size*n_patch_size*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_state*ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size +=     n_enc_state*n_enc_out_chans*1*1*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_out_chans*n_enc_out_chans*3*3*ggml_type_size(GGML_TYPE_F16);
-
-            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-        }
-
-        // image encoder layers
-        {
-            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size += n_enc_layer_global*n_enc_head_dim*(2*n_img_embd - 1)*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_layer_global*n_enc_head_dim*(2*n_img_embd - 1)*ggml_type_size(GGML_TYPE_F16);
-
-            ctx_size += n_enc_layer_local*n_enc_head_dim*(2*n_window_size - 1)*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_layer_local*n_enc_head_dim*(2*n_window_size - 1)*ggml_type_size(GGML_TYPE_F16);
-
-            ctx_size += n_enc_layer*3*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_layer*3*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size += n_enc_layer*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_layer*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size += n_enc_layer*4*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_layer*4*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
-
-            ctx_size += n_enc_layer*4*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
-            ctx_size += n_enc_layer*4*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
-        }
-
-        ctx_size += (8 + 14*n_enc_layer)*ggml_tensor_overhead();
-
-        // prompt encoder
-        {
-            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F16); // 2*(n_enc_out_chans/2)
-
-            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-            ctx_size += n_pt_embd*n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-        }
-
-        ctx_size += (2 + n_pt_embd)*ggml_tensor_overhead();
-
-        // mask decoder
-        {
-            //transformer
-            {
-                const int tfm_layers_count = 2;
-                const int qkv_count = 3;
-                const int norm_count = 4;
-                const int n_hypernet_mpls_count = 4;
-
-                // self_attn
-                ctx_size += tfm_layers_count*qkv_count*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += tfm_layers_count*qkv_count*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
-                ctx_size += tfm_layers_count*n_enc_state*                      ggml_type_size(GGML_TYPE_F32);
-
-                // all norms
-                ctx_size += tfm_layers_count*norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-                ctx_size += tfm_layers_count*norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-
-                // cross_attn_token_to_img
-                ctx_size += tfm_layers_count*qkv_count*n_enc_state*(n_enc_state/2)*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += tfm_layers_count*qkv_count*(n_enc_state/2)*            ggml_type_size(GGML_TYPE_F32);
-                ctx_size += tfm_layers_count*n_enc_state*                          ggml_type_size(GGML_TYPE_F32);
-
-                // mlp
-                ctx_size += tfm_layers_count*8*n_enc_out_chans*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += tfm_layers_count*8*n_enc_out_chans*                ggml_type_size(GGML_TYPE_F32);
-                ctx_size += tfm_layers_count*n_enc_out_chans*8*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += tfm_layers_count*n_enc_out_chans*                  ggml_type_size(GGML_TYPE_F32);
-
-                // cross_attn_img_to_token
-                ctx_size += tfm_layers_count*qkv_count*n_enc_state*(n_enc_state/2)*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += tfm_layers_count*qkv_count*(n_enc_state/2)*            ggml_type_size(GGML_TYPE_F32);
-                ctx_size += tfm_layers_count*n_enc_state*                          ggml_type_size(GGML_TYPE_F32);
-
-                // transformer_final_attn_token_to_img
-                ctx_size += qkv_count*n_enc_state*(n_enc_state/2)*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += qkv_count*(n_enc_state/2)*            ggml_type_size(GGML_TYPE_F32);
-                ctx_size += n_enc_state*                          ggml_type_size(GGML_TYPE_F32);
-
-                // transformer_norm_final
-                ctx_size += norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-                ctx_size += norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
-
-                // output_upscaling
-                ctx_size += n_enc_out_chans*n_img_embd*2*2*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += 3*n_img_embd*                  ggml_type_size(GGML_TYPE_F32);
-                ctx_size += n_enc_out_chans*n_img_embd*(n_img_embd/2)*2*2*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += (n_img_embd/2)*                               ggml_type_size(GGML_TYPE_F32);
-
-                // output_hypernetworks_mlps
-                ctx_size += n_hypernet_mpls_count*2*n_enc_out_chans*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += n_hypernet_mpls_count*2*n_enc_out_chans*                ggml_type_size(GGML_TYPE_F32);
-                ctx_size += n_hypernet_mpls_count*n_enc_out_chans*(n_img_embd/2)*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += n_hypernet_mpls_count*(n_img_embd/2)*                ggml_type_size(GGML_TYPE_F32);
-
-                // iou_prediction_head
-                ctx_size += 2*n_enc_out_chans*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += 2*n_enc_out_chans*                ggml_type_size(GGML_TYPE_F32);
-                ctx_size += n_pt_embd*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
-                ctx_size += n_pt_embd*                ggml_type_size(GGML_TYPE_F32);
-
-                // iou_token_w
-                ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-
-                // mask_tokens_w
-                ctx_size += n_pt_embd*n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
-            }
-        }
-        fprintf(stderr, "%s: ggml ctx size = %6.2f MB\n", __func__, ctx_size/(1024.0*1024.0));
-
-        return ctx_size;
-    }();
-
-    // create the ggml context
-    {
-        struct ggml_init_params params = {
-            /*.mem_size   =*/ ctx_size,
-            /*.mem_buffer =*/ NULL,
-            /*.no_alloc   =*/ false,
-        };
-
-        ctx = ggml_init(params);
-        if (!ctx) {
-            fprintf(stderr, "%s: ggml_init() failed\n", __func__);
-            return false;
-        }
-    }
-
-    // prepare memory for the weights
-    {
-        const auto & hparams = model.hparams;
-
-        const int32_t n_enc_state      = hparams.n_enc_state;
-        const int32_t n_enc_layer      = hparams.n_enc_layer;
-        const int32_t n_enc_head_dim   = hparams.n_enc_head_dim();
-        const int32_t n_enc_out_chans  = hparams.n_enc_out_chans;
-        const int32_t n_pt_embd        = hparams.n_pt_embd;
-
-        const int32_t n_img_embd    = hparams.n_img_embd();
-        const int32_t n_window_size = hparams.n_window_size();
-        const int32_t n_patch_size  = hparams.n_patch_size();
-
-        model.enc_img.layers.resize(n_enc_layer);
-
-        // image encoder
-        {
-            auto & enc = model.enc_img;
-
-            enc.pe = ggml_new_tensor_4d(ctx, GGML_TYPE_F32, n_enc_state, n_img_embd, n_img_embd, 1);
-
-            enc.proj_w = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, n_patch_size, n_patch_size,           3, n_enc_state);
-            enc.proj_b = ggml_new_tensor_3d(ctx, GGML_TYPE_F32,            1,            1, n_enc_state);
-
-            enc.neck_conv_0 = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, 1, 1, n_enc_state,     n_enc_out_chans);
-            enc.neck_conv_1 = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, 3, 3, n_enc_out_chans, n_enc_out_chans);
-
-            enc.neck_norm_0_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-            enc.neck_norm_0_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-            enc.neck_norm_1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-            enc.neck_norm_1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-            model.tensors["image_encoder.pos_embed"] = enc.pe;
-
-            model.tensors["image_encoder.patch_embed.proj.weight"] = enc.proj_w;
-            model.tensors["image_encoder.patch_embed.proj.bias"]   = enc.proj_b;
-
-            model.tensors["image_encoder.neck.0.weight"] = enc.neck_conv_0;
-            model.tensors["image_encoder.neck.2.weight"] = enc.neck_conv_1;
-
-            model.tensors["image_encoder.neck.1.weight"] = enc.neck_norm_0_w;
-            model.tensors["image_encoder.neck.1.bias"]   = enc.neck_norm_0_b;
-
-            model.tensors["image_encoder.neck.3.weight"] = enc.neck_norm_1_w;
-            model.tensors["image_encoder.neck.3.bias"]   = enc.neck_norm_1_b;
-
-            for (int i = 0; i < n_enc_layer; ++i) {
-                auto & layer = enc.layers[i];
-
-                layer.norm1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
-                layer.norm1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
-
-                if (hparams.is_global_attn(i)) {
-                    layer.rel_pos_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_img_embd - 1);
-                    layer.rel_pos_h = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_img_embd - 1);
-                } else {
-                    layer.rel_pos_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_window_size - 1);
-                    layer.rel_pos_h = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_window_size - 1);
-                }
-
-                layer.qkv_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16,   n_enc_state, 3*n_enc_state);
-                layer.qkv_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 3*n_enc_state);
-
-                layer.proj_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16,  n_enc_state,   n_enc_state);
-                layer.proj_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32,  n_enc_state);
-
-                layer.norm2_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
-                layer.norm2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
-
-                layer.mlp_lin1_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16,   n_enc_state, 4*n_enc_state);
-                layer.mlp_lin1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 4*n_enc_state);
-
-                layer.mlp_lin2_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, 4*n_enc_state,   n_enc_state);
-                layer.mlp_lin2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32,   n_enc_state);
-
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm1.weight"] = layer.norm1_w;
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm1.bias"]   = layer.norm1_b;
-
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.rel_pos_w"] = layer.rel_pos_w;
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.rel_pos_h"] = layer.rel_pos_h;
-
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.qkv.weight"] = layer.qkv_w;
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.qkv.bias"]   = layer.qkv_b;
-
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.proj.weight"] = layer.proj_w;
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.proj.bias"]   = layer.proj_b;
-
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm2.weight"] = layer.norm2_w;
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm2.bias"]   = layer.norm2_b;
-
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin1.weight"] = layer.mlp_lin1_w;
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin1.bias"]   = layer.mlp_lin1_b;
-
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin2.weight"] = layer.mlp_lin2_w;
-                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin2.bias"]   = layer.mlp_lin2_b;
-            }
-        }
-
-        // prompt encoder
-        {
-            auto & enc = model.enc_prompt;
-
-            enc.pe = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, n_enc_out_chans/2, 2);
-
-            enc.not_a_pt_embd_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-            enc.no_mask_embd_w  = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-            model.tensors["prompt_encoder.pe_layer.positional_encoding_gaussian_matrix"] = enc.pe;
-            model.tensors["prompt_encoder.not_a_point_embed.weight"] = enc.not_a_pt_embd_w;
-            model.tensors["prompt_encoder.no_mask_embed.weight"]     = enc.no_mask_embd_w;
-
-            enc.pt_embd.resize(n_pt_embd);
-            for (int i = 0; i < n_pt_embd; i++) {
-                enc.pt_embd[i] = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                model.tensors["prompt_encoder.point_embeddings." + std::to_string(i) + ".weight"] = enc.pt_embd[i];
-            }
-        }
-
-        // mask decoder
-        {
-            auto & dec = model.dec;
-            auto & tfm_layers = dec.transformer_layers;
-
-            const int tfm_layers_count = 2;
-            tfm_layers.resize(tfm_layers_count);
-            for (int i = 0; i < tfm_layers_count; ++i) {
-                auto& l = tfm_layers[i];
-                l.self_attn.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-                l.self_attn.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                l.self_attn.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-                l.self_attn.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                l.self_attn.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-                l.self_attn.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                l.self_attn.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-                l.self_attn.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                l.norm1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                l.norm1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                l.cross_attn_token_to_img.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-                l.cross_attn_token_to_img.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-                l.cross_attn_token_to_img.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-                l.cross_attn_token_to_img.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-                l.cross_attn_token_to_img.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-                l.cross_attn_token_to_img.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-                l.cross_attn_token_to_img.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans/2, n_enc_out_chans);
-                l.cross_attn_token_to_img.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                l.norm2_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                l.norm2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                l.mlp_lin1_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, 8*n_enc_out_chans);
-                l.mlp_lin1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 8*n_enc_out_chans);
-                l.mlp_lin2_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, 8*n_enc_out_chans, n_enc_out_chans);
-                l.mlp_lin2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                l.norm3_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                l.norm3_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                l.norm4_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                l.norm4_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                l.cross_attn_img_to_token.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-                l.cross_attn_img_to_token.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-                l.cross_attn_img_to_token.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-                l.cross_attn_img_to_token.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-                l.cross_attn_img_to_token.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-                l.cross_attn_img_to_token.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-                l.cross_attn_img_to_token.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans/2, n_enc_out_chans);
-                l.cross_attn_img_to_token.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-                const auto prefix = "mask_decoder.transformer.layers." + std::to_string(i) + ".";
-                model.tensors[prefix + "self_attn.q_proj.weight"] = l.self_attn.q_w;
-                model.tensors[prefix + "self_attn.q_proj.bias"]   = l.self_attn.q_b;
-                model.tensors[prefix + "self_attn.k_proj.weight"] = l.self_attn.k_w;
-                model.tensors[prefix + "self_attn.k_proj.bias"]   = l.self_attn.k_b;
-                model.tensors[prefix + "self_attn.v_proj.weight"] = l.self_attn.v_w;
-                model.tensors[prefix + "self_attn.v_proj.bias"]   = l.self_attn.v_b;
-                model.tensors[prefix + "self_attn.out_proj.weight"] = l.self_attn.out_w;
-                model.tensors[prefix + "self_attn.out_proj.bias"]   = l.self_attn.out_b;
-
-                model.tensors[prefix + "norm1.weight"] = l.norm1_w;
-                model.tensors[prefix + "norm1.bias"]   = l.norm1_b;
-
-                model.tensors[prefix + "cross_attn_token_to_image.q_proj.weight"] = l.cross_attn_token_to_img.q_w;
-                model.tensors[prefix + "cross_attn_token_to_image.q_proj.bias"]   = l.cross_attn_token_to_img.q_b;
-                model.tensors[prefix + "cross_attn_token_to_image.k_proj.weight"] = l.cross_attn_token_to_img.k_w;
-                model.tensors[prefix + "cross_attn_token_to_image.k_proj.bias"]   = l.cross_attn_token_to_img.k_b;
-                model.tensors[prefix + "cross_attn_token_to_image.v_proj.weight"] = l.cross_attn_token_to_img.v_w;
-                model.tensors[prefix + "cross_attn_token_to_image.v_proj.bias"]   = l.cross_attn_token_to_img.v_b;
-                model.tensors[prefix + "cross_attn_token_to_image.out_proj.weight"] = l.cross_attn_token_to_img.out_w;
-                model.tensors[prefix + "cross_attn_token_to_image.out_proj.bias"]   = l.cross_attn_token_to_img.out_b;
-
-                model.tensors[prefix + "norm2.weight"] = l.norm2_w;
-                model.tensors[prefix + "norm2.bias"]   = l.norm2_b;
-
-                model.tensors[prefix + "mlp.lin1.weight"] = l.mlp_lin1_w;
-                model.tensors[prefix + "mlp.lin1.bias"]   = l.mlp_lin1_b;
-                model.tensors[prefix + "mlp.lin2.weight"] = l.mlp_lin2_w;
-                model.tensors[prefix + "mlp.lin2.bias"]   = l.mlp_lin2_b;
-
-                model.tensors[prefix + "norm3.weight"] = l.norm3_w;
-                model.tensors[prefix + "norm3.bias"]   = l.norm3_b;
-                model.tensors[prefix + "norm4.weight"] = l.norm4_w;
-                model.tensors[prefix + "norm4.bias"]   = l.norm4_b;
-
-                model.tensors[prefix + "cross_attn_image_to_token.q_proj.weight"] = l.cross_attn_img_to_token.q_w;
-                model.tensors[prefix + "cross_attn_image_to_token.q_proj.bias"]   = l.cross_attn_img_to_token.q_b;
-                model.tensors[prefix + "cross_attn_image_to_token.k_proj.weight"] = l.cross_attn_img_to_token.k_w;
-                model.tensors[prefix + "cross_attn_image_to_token.k_proj.bias"]   = l.cross_attn_img_to_token.k_b;
-                model.tensors[prefix + "cross_attn_image_to_token.v_proj.weight"] = l.cross_attn_img_to_token.v_w;
-                model.tensors[prefix + "cross_attn_image_to_token.v_proj.bias"]   = l.cross_attn_img_to_token.v_b;
-                model.tensors[prefix + "cross_attn_image_to_token.out_proj.weight"] = l.cross_attn_img_to_token.out_w;
-                model.tensors[prefix + "cross_attn_image_to_token.out_proj.bias"]   = l.cross_attn_img_to_token.out_b;
-            }
-
-            dec.transformer_final_attn_token_to_img.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-            dec.transformer_final_attn_token_to_img.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-            dec.transformer_final_attn_token_to_img.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-            dec.transformer_final_attn_token_to_img.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-            dec.transformer_final_attn_token_to_img.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
-            dec.transformer_final_attn_token_to_img.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
-            dec.transformer_final_attn_token_to_img.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans/2, n_enc_out_chans);
-            dec.transformer_final_attn_token_to_img.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.q_proj.weight"] = dec.transformer_final_attn_token_to_img.q_w;
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.q_proj.bias"]   = dec.transformer_final_attn_token_to_img.q_b;
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.k_proj.weight"] = dec.transformer_final_attn_token_to_img.k_w;
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.k_proj.bias"]   = dec.transformer_final_attn_token_to_img.k_b;
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.v_proj.weight"] = dec.transformer_final_attn_token_to_img.v_w;
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.v_proj.bias"]   = dec.transformer_final_attn_token_to_img.v_b;
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.out_proj.weight"] = dec.transformer_final_attn_token_to_img.out_w;
-            model.tensors["mask_decoder.transformer.final_attn_token_to_image.out_proj.bias"]   = dec.transformer_final_attn_token_to_img.out_b;
-
-            dec.transformer_norm_final_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-            dec.transformer_norm_final_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-
-            model.tensors["mask_decoder.transformer.norm_final_attn.weight"] = dec.transformer_norm_final_w;
-            model.tensors["mask_decoder.transformer.norm_final_attn.bias"]   = dec.transformer_norm_final_b;
-
-            dec.output_upscaling_0_w = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, 2, 2, n_img_embd, n_enc_out_chans);
-            dec.output_upscaling_0_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd);
-            dec.output_upscaling_1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd);
-            dec.output_upscaling_1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd);
-            dec.output_upscaling_3_w = ggml_new_tensor_4d(ctx, GGML_TYPE_F16,  2, 2, n_img_embd/2, n_img_embd);
-            dec.output_upscaling_3_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd/2);
-
-            model.tensors["mask_decoder.output_upscaling.0.weight"] = dec.output_upscaling_0_w;
-            model.tensors["mask_decoder.output_upscaling.0.bias"]   = dec.output_upscaling_0_b;
-            model.tensors["mask_decoder.output_upscaling.1.weight"] = dec.output_upscaling_1_w;
-            model.tensors["mask_decoder.output_upscaling.1.bias"]   = dec.output_upscaling_1_b;
-            model.tensors["mask_decoder.output_upscaling.3.weight"] = dec.output_upscaling_3_w;
-            model.tensors["mask_decoder.output_upscaling.3.bias"]   = dec.output_upscaling_3_b;
-
-            const int n_hypernet_mpls_count = 4;
-            dec.output_hypernet_mlps.resize(n_hypernet_mpls_count);
-            for (int i = 0; i < n_hypernet_mpls_count; ++i) {
-                auto& mlp = dec.output_hypernet_mlps[i];
-
-                mlp.w_0 = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-                mlp.b_0 = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                mlp.w_1 = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-                mlp.b_1 = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-                mlp.w_2 = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_img_embd/2);
-                mlp.b_2 = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd/2);
-
-                const auto prefix = "mask_decoder.output_hypernetworks_mlps." + std::to_string(i) + ".";
-                model.tensors[prefix + "layers.0.weight"] = mlp.w_0;
-                model.tensors[prefix + "layers.0.bias"]   = mlp.b_0;
-                model.tensors[prefix + "layers.1.weight"] = mlp.w_1;
-                model.tensors[prefix + "layers.1.bias"]   = mlp.b_1;
-                model.tensors[prefix + "layers.2.weight"] = mlp.w_2;
-                model.tensors[prefix + "layers.2.bias"]   = mlp.b_2;
-            }
-
-            dec.iou_prediction_head_0_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-            dec.iou_prediction_head_0_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-            dec.iou_prediction_head_1_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
-            dec.iou_prediction_head_1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
-            dec.iou_prediction_head_2_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_pt_embd);
-            dec.iou_prediction_head_2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_pt_embd);
-
-            dec.iou_token_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, n_enc_out_chans, 1);
-            dec.mask_tokens_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, n_enc_out_chans, n_pt_embd);
-
-            model.tensors["mask_decoder.iou_prediction_head.layers.0.weight"] = dec.iou_prediction_head_0_w;
-            model.tensors["mask_decoder.iou_prediction_head.layers.0.bias"]   = dec.iou_prediction_head_0_b;
-            model.tensors["mask_decoder.iou_prediction_head.layers.1.weight"] = dec.iou_prediction_head_1_w;
-            model.tensors["mask_decoder.iou_prediction_head.layers.1.bias"]   = dec.iou_prediction_head_1_b;
-            model.tensors["mask_decoder.iou_prediction_head.layers.2.weight"] = dec.iou_prediction_head_2_w;
-            model.tensors["mask_decoder.iou_prediction_head.layers.2.bias"]   = dec.iou_prediction_head_2_b;
-
-            model.tensors["mask_decoder.iou_token.weight"] = dec.iou_token_w;
-            model.tensors["mask_decoder.mask_tokens.weight"] = dec.mask_tokens_w;
-        }
-    }
-
-    // load weights
-    {
-        int n_tensors = 0;
-        size_t total_size = 0;
-
-        fprintf(stderr, "%s: ", __func__);
-
-        while (true) {
-            int32_t n_dims;
-            int32_t length;
-            int32_t ftype;
-
-            fin.read(reinterpret_cast<char *>(&n_dims), sizeof(n_dims));
-            fin.read(reinterpret_cast<char *>(&length), sizeof(length));
-            fin.read(reinterpret_cast<char *>(&ftype),  sizeof(ftype));
-
-            if (fin.eof()) {
-                break;
-            }
-
-            int64_t nelements = 1;
-            int64_t ne[4] = { 1, 1, 1, 1 };
-            for (int i = 0; i < n_dims; ++i) {
-                int32_t ne_cur;
-                fin.read(reinterpret_cast<char *>(&ne_cur), sizeof(ne_cur));
-                ne[i] = ne_cur;
-                nelements *= ne[i];
-            }
-
-            std::string name(length, 0);
-            fin.read(&name[0], length);
-
-            if (model.tensors.find(name.data()) == model.tensors.end()) {
-                fprintf(stderr, "%s: unknown tensor '%s' in model file\n", __func__, name.data());
-                return false;
-            }
-
-            auto tensor = model.tensors[name.data()];
-            //printf("ne0 = %jd, ne1 = %jd, ne2 = %jd, ne3 = %jd\n", ne[0], ne[1], ne[2], ne[3]);
-
-            if (ggml_nelements(tensor) != nelements) {
-                fprintf(stderr, "%s: tensor '%s' has wrong size in model file: got %d, expected %d\n",
-                        __func__, name.data(), (int) nelements, (int) ggml_nelements(tensor));
-                return false;
-            }
-
-            if (tensor->ne[0] != ne[0] || tensor->ne[1] != ne[1] || tensor->ne[2] != ne[2] || tensor->ne[3] != ne[3]) {
-                fprintf(stderr, "%s: tensor '%s' has wrong shape in model file: got [%d, %d, %d, %d], expected [%d, %d, %d, %d]\n",
-                        __func__, name.data(),
-                        (int) ne[0], (int) ne[1], (int) ne[2], (int) ne[3],
-                        (int) tensor->ne[0], (int) tensor->ne[1], (int) tensor->ne[2], (int) tensor->ne[3]);
-                return false;
-            }
-
-            size_t bpe = 0;
-
-            switch (ftype) {
-                case 0: bpe = ggml_type_size(GGML_TYPE_F32);  break;
-                case 1: bpe = ggml_type_size(GGML_TYPE_F16);  break;
-                case 2: bpe = ggml_type_size(GGML_TYPE_Q4_0); assert(ne[0] % 64 == 0); break;
-                case 3: bpe = ggml_type_size(GGML_TYPE_Q4_1); assert(ne[0] % 64 == 0); break;
-                default:
-                        {
-                            fprintf(stderr, "%s: unknown ftype %d in model file\n", __func__, ftype);
-                            return false;
-                        }
-            };
-
-            if ((nelements*bpe)/ggml_blck_size(tensor->type) != ggml_nbytes(tensor)) {
-                fprintf(stderr, "%s: tensor '%s' has wrong size in model file: got %zu, expected %zu\n",
-                        __func__, name.data(), ggml_nbytes(tensor), (size_t) nelements*bpe);
-                return false;
-            }
-
-            fin.read(reinterpret_cast<char *>(tensor->data), ggml_nbytes(tensor));
-
-            total_size += ggml_nbytes(tensor);
-            if (++n_tensors % 8 == 0) {
-                fprintf(stderr, ".");
-                fflush(stdout);
-            }
-        }
-
-        if (n_tensors != int(model.tensors.size())) {
-            fprintf(stderr, "%s: model file has %d tensors, but %d tensors were expected\n", __func__, n_tensors, (int) model.tensors.size());
-            return false;
-        }
-
-        fprintf(stderr, " done\n");
-
-        fprintf(stderr, "%s: model size = %8.2f MB / num tensors = %d\n", __func__, total_size/1024.0/1024.0, n_tensors);
-    }
-
-    fin.close();
-
-    return true;
-}
-
-struct ggml_tensor * sam_fill_dense_pe(
-            const sam_model   & model,
-          struct ggml_context * ctx0,
-          struct ggml_cgraph  * gf,
-                  sam_state   & state) {
-    const auto & hparams = model.hparams;
-    const auto & enc     = model.enc_prompt;
-
-
-    const int32_t n_img_embd = hparams.n_img_embd();
-    struct ggml_tensor * xy_embed_stacked = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, 2, n_img_embd, n_img_embd);
-    ggml_set_name(xy_embed_stacked, "xy_embed_stacked");
-    ggml_set_input(xy_embed_stacked);
-
-    struct ggml_tensor * cur = ggml_mul_mat(ctx0, ggml_cont(ctx0, ggml_transpose(ctx0, enc.pe)), xy_embed_stacked);
-
-    cur = ggml_scale(ctx0, cur, float(2.0*M_PI));
-
-    // concat
-    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L192
-    {
-        struct ggml_tensor * t_sin = ggml_map_custom1(ctx0, cur, ggml_sam_sin, GGML_N_TASKS_MAX, NULL);
-        struct ggml_tensor * t_cos = ggml_map_custom1(ctx0, cur, ggml_sam_cos, GGML_N_TASKS_MAX, NULL);
-
-        cur = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, t_sin->ne[0] + t_cos->ne[0], cur->ne[1], cur->ne[2]);
-
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_sin, ggml_view_3d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], t_sin->ne[2], cur->nb[1], cur->nb[2], 0)));
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_cos, ggml_view_3d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], t_sin->ne[2], cur->nb[1], cur->nb[2], t_sin->nb[1])));
-    }
-
-    struct ggml_tensor * pe_img_dense = ggml_cont(ctx0, ggml_permute(ctx0, cur, 2, 0, 1, 3));
-    ggml_build_forward_expand(gf, pe_img_dense);
-
-    return pe_img_dense;
-}
-
-struct ggml_tensor* sam_layer_norm_2d(
-                    struct ggml_context * ctx0,
-                    struct ggml_tensor  * layer,
-                    int                   n_channels,
-                    struct ggml_tensor  * w,
-                    struct ggml_tensor  * b,
-                    float                 eps) {
-    // LayerNorm2d
-    // normalize along channel dimmension
-    // TODO: better implementation
-    layer = ggml_permute(ctx0,
-                ggml_norm(ctx0, ggml_cont(ctx0, ggml_permute(ctx0, layer, 1, 2, 0, 3)), eps),
-                2, 0, 1, 3);
-
-    layer = ggml_add(ctx0,
-              ggml_mul(ctx0,
-                  ggml_repeat(ctx0, ggml_reshape_3d(ctx0, w, 1, 1, n_channels), layer),
-                  layer),
-              ggml_repeat(ctx0, ggml_reshape_3d(ctx0, b, 1, 1, n_channels), layer));
-
-    return layer;
-}
-
-struct ggml_cgraph  * sam_encode_image(
-            const sam_model & model,
-                  sam_state & state,
-        const sam_image_f32 & img) {
-
-    const auto & hparams = model.hparams;
-    const auto & enc     = model.enc_img;
-
-    const int32_t n_enc_state     = hparams.n_enc_state;
-    const int32_t n_enc_layer     = hparams.n_enc_layer;
-    const int32_t n_enc_head      = hparams.n_enc_head;
-    const int32_t n_enc_head_dim  = hparams.n_enc_head_dim();
-    const int32_t n_enc_out_chans = hparams.n_enc_out_chans;
-    const int32_t n_img_size    = hparams.n_img_size();
-    const int32_t n_window_size = hparams.n_window_size();
-
-    struct ggml_init_params ggml_params = {
-        /*.mem_size   =*/ state.buf_compute_img_enc.size(),
-        /*.mem_buffer =*/ state.buf_compute_img_enc.data(),
-        /*.no_alloc   =*/ true, // skip allocating as we use ggml_alloc to allocate exact memory requirements
-    };
-
-    struct ggml_context * ctx0   = ggml_init(ggml_params);
-    struct ggml_cgraph  * gf     = ggml_new_graph(ctx0);
-
-    struct ggml_tensor * inp = ggml_new_tensor_4d(ctx0, GGML_TYPE_F32, n_img_size, n_img_size, 3, 1);
-    ggml_set_name(inp, "inp");
-    ggml_set_input(inp);
-
-    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L392
-    struct ggml_tensor * cur = ggml_conv_2d_sk_p0(ctx0, enc.proj_w, inp);
-    cur = ggml_add_inplace(ctx0,
-            cur,
-            ggml_repeat(ctx0, enc.proj_b, cur));
-
-    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L394
-    // keep in F32
-    cur = ggml_cont(ctx0,
-            ggml_permute(ctx0, cur, 1, 2, 0, 3));
-
-    // convert to F16
-    //cur = ggml_cpy(ctx0,
-    //        ggml_permute(ctx0, cur, 1, 2, 0, 3),
-    //        ggml_new_tensor_3d(ctx0, GGML_TYPE_F16, n_enc_state, n_img_embd, n_img_embd));
-
-    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L108-L109
-    cur = ggml_add_inplace(ctx0, cur, enc.pe);
-
-    struct ggml_tensor * inpL = cur;
-
-    for (int il = 0; il < n_enc_layer; ++il) {
-        const auto & layer = enc.layers[il];
-
-        // norm
-        // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L168
-        {
-            cur = ggml_norm(ctx0, inpL, hparams.eps);
-
-            // cur = ln_0_w*cur + ln_0_b
-            cur = ggml_mul(ctx0, cur, layer.norm1_w);
-            cur = ggml_add_inplace(ctx0, cur, layer.norm1_b);
-        }
-
-        const int64_t w0 = cur->ne[1];
-        const int64_t h0 = cur->ne[2];
-
-        if (hparams.is_global_attn(il) == false) {
-            // local attention layer - apply window partition
-            // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L169-L172
-            cur = ggml_win_part(ctx0, cur, n_window_size);
-        }
-
-        const int64_t W = cur->ne[1];
-        const int64_t H = cur->ne[2];
-
-        // self-attention
-        {
-            cur = ggml_mul_mat(ctx0, layer.qkv_w, cur);
-            cur = ggml_add_inplace(ctx0, cur, layer.qkv_b);
-
-            // split qkv into separate tensors
-            // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L225-L229
-            const int B = cur->ne[3];
-
-            cur = ggml_reshape_4d(ctx0, cur, n_enc_state, 3, W*H, B);
-            cur = ggml_cont(ctx0, ggml_permute(ctx0, cur, 0, 3, 1, 2));
-
-            struct ggml_tensor * Q;
-            struct ggml_tensor * K;
-            struct ggml_tensor * V;
-
-            Q = ggml_view_3d   (ctx0, cur, n_enc_state, W*H, B, cur->nb[1], cur->nb[2], 0*cur->nb[3]);
-            Q = ggml_reshape_4d(ctx0, Q,   n_enc_head_dim, n_enc_head, W*H, B);
-            Q = ggml_cont      (ctx0, ggml_permute(ctx0, Q, 0, 2, 1, 3));
-            Q = ggml_reshape_3d(ctx0, Q,   n_enc_head_dim, W*H, B*n_enc_head);
-
-            K = ggml_view_3d   (ctx0, cur, n_enc_state, W*H, B, cur->nb[1], cur->nb[2], 1*cur->nb[3]);
-            K = ggml_reshape_4d(ctx0, K,   n_enc_head_dim, n_enc_head, W*H, B);
-            K = ggml_cont      (ctx0, ggml_permute(ctx0, K, 0, 2, 1, 3));
-            K = ggml_reshape_3d(ctx0, K,   n_enc_head_dim, W*H, B*n_enc_head);
-
-            V = ggml_view_3d   (ctx0, cur, n_enc_state, W*H, B, cur->nb[1], cur->nb[2], 2*cur->nb[3]);
-            V = ggml_reshape_4d(ctx0, V,   n_enc_head_dim, n_enc_head, W*H, B);
-            V = ggml_cont      (ctx0, ggml_permute(ctx0, V, 1, 2, 0, 3)); // transposed
-            V = ggml_reshape_3d(ctx0, V,   W*H, n_enc_head_dim, B*n_enc_head);
-
-            struct ggml_tensor * KQ = ggml_mul_mat(ctx0, K, Q);
-
-            struct ggml_tensor * KQ_scaled =
-                ggml_scale_inplace(ctx0,
-                        KQ,
-                        1.0f/sqrtf(n_enc_head_dim));
-
-            struct ggml_tensor * rw = ggml_get_rel_pos(ctx0, layer.rel_pos_w, W, W);
-            struct ggml_tensor * rh = ggml_get_rel_pos(ctx0, layer.rel_pos_h, H, H);
-
-            struct ggml_tensor * q_r = ggml_reshape_4d(ctx0, Q, n_enc_head_dim, W, H, B*n_enc_head);
-
-            struct ggml_tensor * rel_w = ggml_cont(ctx0, ggml_permute(ctx0,
-                        ggml_mul_mat(ctx0,
-                            rw,
-                            ggml_cont(ctx0, ggml_permute(ctx0, q_r, 0, 2, 1, 3))),
-                        0, 2, 1, 3));
-            struct ggml_tensor * rel_h = ggml_mul_mat(ctx0, rh, q_r);
-
-            struct ggml_tensor * attn = ggml_add_rel_pos_inplace(ctx0, KQ_scaled, rel_w, rel_h);
-
-            struct ggml_tensor * KQ_soft_max = ggml_soft_max_inplace(ctx0, attn);
-
-            struct ggml_tensor * KQV = ggml_mul_mat(ctx0, V, KQ_soft_max);
-
-            cur =
-                ggml_reshape_4d(ctx0,
-                        ggml_cont(ctx0,
-                            ggml_permute(ctx0,
-                                ggml_reshape_4d(ctx0, KQV, n_enc_head_dim, W*H, n_enc_head, B),
-                                0, 2, 1, 3)),
-                        n_enc_state, W, H, B);
-
-            cur = ggml_mul_mat(ctx0, layer.proj_w, cur);
-            cur = ggml_add_inplace(ctx0, cur, layer.proj_b);
-        }
-
-        if (hparams.is_global_attn(il) == false) {
-            // local attention layer - reverse window partition
-            cur = ggml_win_unpart(ctx0, cur, w0, h0, n_window_size);
-        }
-
-        cur = ggml_add_inplace(ctx0, cur, inpL);
-
-        struct ggml_tensor * inpFF = cur;
-
-        // feed-forward network
-        {
-            // norm
-            {
-                cur = ggml_norm(ctx0, inpFF, hparams.eps);
-
-                // cur = mlp_ln_w*cur + mlp_ln_b
-                cur = ggml_mul(ctx0, cur, layer.norm2_w);
-                cur = ggml_add_inplace(ctx0, cur, layer.norm2_b);
-            }
-
-            // fully connected
-            cur = ggml_mul_mat(ctx0, layer.mlp_lin1_w, cur);
-            cur = ggml_add_inplace(ctx0, cur, layer.mlp_lin1_b);
-
-            // GELU activation
-            cur = ggml_gelu(ctx0, cur);
-
-            // projection
-            cur = ggml_mul_mat(ctx0, layer.mlp_lin2_w, cur);
-            cur = ggml_add_inplace(ctx0, cur, layer.mlp_lin2_b);
-        }
-
-        inpL = ggml_add(ctx0, cur, inpFF);
-    }
-
-    cur = ggml_cont(ctx0, ggml_permute(ctx0, inpL, 2, 0, 1, 3));
-
-    cur = ggml_conv_2d_sk_p0(ctx0, enc.neck_conv_0, cur);
-
-    cur = sam_layer_norm_2d(ctx0, cur, n_enc_out_chans, enc.neck_norm_0_w, enc.neck_norm_0_b, hparams.eps);
-
-    cur = ggml_conv_2d_s1_ph(ctx0, enc.neck_conv_1, cur);
-
-    cur = sam_layer_norm_2d(ctx0, cur, n_enc_out_chans, enc.neck_norm_1_w, enc.neck_norm_1_b, hparams.eps);
-
-    cur = ggml_cpy(ctx0, cur, state.embd_img);
-
-    ggml_build_forward_expand(gf, cur);
-    ggml_disconnect_node_from_graph(state.embd_img);
-
-    //ggml_graph_print(&gf);
-
-    ggml_free(ctx0);
-
-    ggml_gallocr_alloc_graph(state.allocr, gf);
-
-    {
-        struct ggml_tensor * inp = ggml_graph_get_tensor(gf, "inp");
-        float * data = (float *) ggml_get_data(inp);
-
-        const int nx = img.nx;
-        const int ny = img.ny;
-        const int n  = nx*ny;
-
-        GGML_ASSERT(nx == n_img_size && ny == n_img_size);
-
-        for (int k = 0; k < 3; k++) {
-            for (int y = 0; y < ny; y++) {
-                for (int x = 0; x < nx; x++) {
-                    data[k*n + y*nx + x] = img.data[3*(y*nx + x) + k];
-                }
-            }
-        }
-    }
-
-    return gf;
-}
-
-
-struct prompt_encoder_result {
-    struct ggml_tensor * embd_prompt_sparse = {};
-    struct ggml_tensor * embd_prompt_dense = {};
-};
-
-// encode a prompt
-//
-// - points
-// - boxes
-// - masks
-//
-// TODO: currently just encode a single point for simplicity
-//
-prompt_encoder_result sam_encode_prompt(
-        const sam_model     & model,
-        struct ggml_context * ctx0,
-        struct ggml_cgraph  * gf,
-                  sam_state & state) {
-
-    const auto & hparams = model.hparams;
-    const auto & enc = model.enc_prompt;
-
-    struct ggml_tensor * inp = ggml_new_tensor_2d(ctx0, GGML_TYPE_F32, 2, 2);
-    ggml_set_name(inp, "prompt_input");
-    ggml_set_input(inp);
-
-
-    struct ggml_tensor * cur = ggml_mul_mat(ctx0, ggml_cont(ctx0, ggml_transpose(ctx0, enc.pe)), inp);
-
-    cur = ggml_scale(ctx0, cur, float(2.0*M_PI));
-
-    // concat
-    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L192
-    {
-        struct ggml_tensor * t_sin = ggml_map_custom1(ctx0, cur, ggml_sam_sin, GGML_N_TASKS_MAX, NULL);
-        struct ggml_tensor * t_cos = ggml_map_custom1(ctx0, cur, ggml_sam_cos, GGML_N_TASKS_MAX, NULL);
-
-        cur = ggml_new_tensor_2d(ctx0, GGML_TYPE_F32, t_sin->ne[0] + t_cos->ne[0], cur->ne[1]);
-
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_sin, ggml_view_2d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], cur->nb[1], 0)));
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_cos, ggml_view_2d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], cur->nb[1], t_sin->nb[1])));
-
-        // overwrite label == -1 with not_a_point_embed.weight
-        // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L86
-        // TODO: extend for multiple points
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, enc.not_a_pt_embd_w, ggml_view_2d(ctx0, cur, cur->ne[0], 1, cur->nb[1], cur->nb[1])));
-    }
-
-    // add point_embeddings[1] to label == 1
-    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L90
-    struct ggml_tensor * v = ggml_view_2d(ctx0, cur, cur->ne[0], 1, cur->nb[1], 0);
-    ggml_build_forward_expand(gf, ggml_cpy(ctx0, ggml_add_inplace(ctx0, v, enc.pt_embd[1]), v));
-
-    struct ggml_tensor * embd_prompt_sparse = cur;
-    ggml_build_forward_expand(gf, embd_prompt_sparse);
-
-    struct ggml_tensor * embd_prompt_dense = ggml_repeat(ctx0,
-            ggml_cont(ctx0,
-                ggml_view_3d(ctx0, enc.no_mask_embd_w,
-                    1, 1, enc.no_mask_embd_w->ne[0], enc.no_mask_embd_w->nb[0], enc.no_mask_embd_w->nb[0], 0)),
-            ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, hparams.n_img_embd(), hparams.n_img_embd(), hparams.n_enc_out_chans));
-
-    ggml_build_forward_expand(gf, embd_prompt_dense);
-
-    //printf("used_mem = %zu\n", ggml_used_mem(ctx0));
-
-    prompt_encoder_result res;
-    res.embd_prompt_sparse = embd_prompt_sparse;
-    res.embd_prompt_dense  = embd_prompt_dense;
-    return res;
-}
-
-struct ggml_tensor* sam_decode_mask_transformer_attn(
-    const sam_layer_dec_transformer_attn & attn,
-                      struct ggml_tensor * queries,
-                      struct ggml_tensor * keys,
-                      struct ggml_tensor * values,
-                     struct ggml_context * ctx0,
-                         const sam_model & model) {
-    const auto & hparams = model.hparams;
-    const int n_head = hparams.n_dec_heads;
-
-    struct ggml_tensor * Qcur = {};
-    struct ggml_tensor * Kcur = {};
-    struct ggml_tensor * Vcur = {};
-
-    Qcur = ggml_mul_mat(ctx0, attn.q_w, queries);
-    Qcur = ggml_add_inplace(ctx0, Qcur, attn.q_b);
-
-    Kcur = ggml_mul_mat(ctx0, attn.k_w, keys);
-    Kcur = ggml_add_inplace(ctx0, Kcur, attn.k_b);
-
-    Vcur = ggml_mul_mat(ctx0, attn.v_w, values);
-    Vcur = ggml_add_inplace(ctx0, Vcur, attn.v_b);
-
-    struct ggml_tensor * Q = {};
-    struct ggml_tensor * K = {};
-    struct ggml_tensor * V = {};
-
-    Q = ggml_reshape_4d(ctx0, Qcur, Qcur->ne[0]/n_head, n_head, Qcur->ne[1], Qcur->ne[2]);
-    Q = ggml_cont(ctx0, ggml_permute(ctx0, Q, 0, 2, 1, 3));
-
-    K = ggml_reshape_4d(ctx0, Kcur, Kcur->ne[0]/n_head, n_head, Kcur->ne[1], Kcur->ne[2]);
-    K = ggml_cont(ctx0, ggml_permute(ctx0, K, 0, 2, 1, 3));
-
-    V = ggml_reshape_4d(ctx0, Vcur, Vcur->ne[0]/n_head, n_head, Vcur->ne[1], Vcur->ne[2]);
-    V = ggml_cont(ctx0, ggml_permute(ctx0, V, 0, 2, 1, 3));
-
-    // Q * K
-    struct ggml_tensor * KQ = ggml_mul_mat(ctx0, K, Q);
-
-    struct ggml_tensor * KQ_scaled = ggml_scale_inplace(ctx0, KQ, 1.0f/sqrt(float(Q->ne[0])));
-
-    struct ggml_tensor * KQ_soft_max = ggml_soft_max_inplace(ctx0, KQ_scaled);
-
-    struct ggml_tensor * KQV = ggml_mul_mat(ctx0, KQ_soft_max, ggml_cont(ctx0, ggml_transpose(ctx0, V)));
-
-    struct ggml_tensor * KQV_merged = ggml_cont(ctx0, ggml_transpose(ctx0, KQV));
-    KQV_merged = ggml_cont(ctx0, ggml_permute(ctx0, KQV_merged, 0, 2, 1, 3));
-    KQV_merged = ggml_reshape_3d(ctx0, KQV_merged, KQV_merged->ne[0]*KQV_merged->ne[1], KQV_merged->ne[2], KQV_merged->ne[3]);
-    KQV_merged = ggml_mul_mat(ctx0, attn.out_w, KQV_merged);
-    KQV_merged = ggml_add_inplace(ctx0, KQV_merged, attn.out_b);
-
-    return KQV_merged;
-}
-
-struct ggml_tensor * sam_decode_mask_mlp_relu_3(
-     struct ggml_tensor * in,
-     struct ggml_tensor * w_0,
-     struct ggml_tensor * b_0,
-     struct ggml_tensor * w_1,
-     struct ggml_tensor * b_1,
-     struct ggml_tensor * w_2,
-     struct ggml_tensor * b_2,
-    struct ggml_context * ctx0) {
-
-    struct ggml_tensor * cur = {};
-    cur = ggml_mul_mat(ctx0, w_0, in);
-    cur = ggml_add_inplace(ctx0, cur, b_0);
-
-    cur = ggml_relu_inplace(ctx0, cur);
-
-    cur = ggml_mul_mat(ctx0, w_1, cur);
-    cur = ggml_add_inplace(ctx0, cur, b_1);
-
-    cur = ggml_relu_inplace(ctx0, cur);
-
-    cur = ggml_mul_mat(ctx0, w_2, cur);
-    cur = ggml_add_inplace(ctx0, cur, b_2);
-
-    return cur;
-}
-
-bool sam_decode_mask(
-                    const sam_model & model,
-        const prompt_encoder_result & prompt,
-                 struct ggml_tensor * pe_img,
-                struct ggml_context * ctx0,
-                struct ggml_cgraph  * gf,
-                          sam_state & state) {
-
-    const auto & hparams = model.hparams;
-    const auto & dec = model.dec;
-    const int n_img_embd = hparams.n_img_embd();
-
-    struct ggml_tensor * tokens = {};
-    {
-        // Concatenate output tokens
-        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L120
-        const auto& sparse = prompt.embd_prompt_sparse;
-
-        tokens = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, dec.iou_token_w->ne[0], dec.iou_token_w->ne[1] + dec.mask_tokens_w->ne[1] + sparse->ne[1], sparse->ne[2]);
-
-        const size_t offsets[3] = { 0, dec.iou_token_w->ne[1]*tokens->nb[1], dec.iou_token_w->ne[1]*tokens->nb[1] + dec.mask_tokens_w->ne[1]*tokens->nb[1] };
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, dec.iou_token_w,   ggml_view_2d(ctx0, tokens, tokens->ne[0], dec.iou_token_w->ne[1],   tokens->nb[1], offsets[0])));
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, dec.mask_tokens_w, ggml_view_2d(ctx0, tokens, tokens->ne[0], dec.mask_tokens_w->ne[1], tokens->nb[1], offsets[1])));
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, sparse,            ggml_view_2d(ctx0, tokens, tokens->ne[0], sparse->ne[1],            tokens->nb[1], offsets[2])));
-        // TODO: Sparse prompt embeddings can have more than one point
-    }
-
-
-    struct ggml_tensor * src = {};
-    struct ggml_tensor * pos_src = {};
-    int srcNE[4] = { 0, 0, 0, 0 };
-    {
-        // Expand per-image data in the batch direction to be per-mask
-        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L125
-        src = ggml_new_tensor_4d(ctx0, GGML_TYPE_F32, state.embd_img->ne[0], state.embd_img->ne[1], state.embd_img->ne[2], tokens->ne[2]);
-
-        src = ggml_add(ctx0,
-            ggml_repeat(ctx0,
-                state.embd_img,
-                src),
-            prompt.embd_prompt_dense);
-
-        srcNE[0] = src->ne[0];
-        srcNE[1] = src->ne[1];
-        srcNE[2] = src->ne[2];
-        srcNE[3] = src->ne[3];
-
-        // flatten & permute
-        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L83
-        src = ggml_cont(ctx0, ggml_permute(ctx0,
-            ggml_view_3d(ctx0,
-                src,
-                src->ne[0]*src->ne[1],
-                src->ne[2],
-                src->ne[3],
-                src->nb[2],
-                src->nb[3],
-                0),
-            1, 0, 2, 3));
-
-        pos_src = ggml_new_tensor_4d(ctx0, GGML_TYPE_F32, pe_img->ne[0], pe_img->ne[1], pe_img->ne[2], tokens->ne[2]);
-        pos_src = ggml_repeat(ctx0,
-            pe_img,
-            pos_src);
-
-        // flatten & permute
-        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L83
-        pos_src = ggml_cont(ctx0, ggml_permute(ctx0,
-            ggml_view_3d(ctx0,
-                pos_src,
-                pos_src->ne[0]*pos_src->ne[1],
-                pos_src->ne[2],
-                pos_src->ne[3],
-                pos_src->nb[2],
-                pos_src->nb[3],
-                0),
-            1, 0, 2, 3));
-    }
-
-    struct ggml_tensor * queries = tokens;
-    struct ggml_tensor * keys = src;
-    {
-        // Run the transformer
-        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L62
-        for (int i = 0; i < int(model.dec.transformer_layers.size()); ++i) {
-            const auto& tfm_layer = model.dec.transformer_layers[i];
-
-            // Self attention block
-            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L154
-            const bool skip_first_layer_pe = i == 0;
-            if (skip_first_layer_pe) {
-                queries = sam_decode_mask_transformer_attn(tfm_layer.self_attn, queries, queries, queries, ctx0, model);
-            }
-            else {
-                struct ggml_tensor * q_0 = ggml_add(ctx0, queries, tokens);
-
-                struct ggml_tensor * self_attn = sam_decode_mask_transformer_attn(tfm_layer.self_attn, q_0, q_0, queries, ctx0, model);
-                queries = ggml_add(ctx0, queries, self_attn);
-            }
-
-            queries = ggml_norm(ctx0, queries, hparams.eps_decoder_transformer);
-            queries = ggml_add_inplace(ctx0,
-                    ggml_mul(ctx0, queries, tfm_layer.norm1_w),
-                    tfm_layer.norm1_b);
-
-            // Cross attention block, tokens attending to image embedding
-            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L163
-            struct ggml_tensor * q_1 = ggml_add(ctx0, queries, tokens);
-            struct ggml_tensor * k_1 = ggml_add(ctx0, keys, pos_src);
-
-            struct ggml_tensor * cross_attn_token_to_img = sam_decode_mask_transformer_attn(tfm_layer.cross_attn_token_to_img, q_1, k_1, keys, ctx0, model);
-
-            queries = ggml_add_inplace(ctx0, queries, cross_attn_token_to_img);
-            queries = ggml_norm_inplace(ctx0, queries, hparams.eps_decoder_transformer);
-            queries = ggml_add_inplace(ctx0,
-                    ggml_mul(ctx0, queries, tfm_layer.norm2_w),
-                    tfm_layer.norm2_b);
-
-            // MLP block
-            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L170
-            struct ggml_tensor * mlp_out = ggml_mul_mat(ctx0,
-                tfm_layer.mlp_lin1_w,
-                queries);
-
-            mlp_out = ggml_add_inplace(ctx0, mlp_out, tfm_layer.mlp_lin1_b);
-
-            // RELU activation
-            mlp_out = ggml_relu_inplace(ctx0, mlp_out);
-            mlp_out = ggml_mul_mat(ctx0, tfm_layer.mlp_lin2_w, mlp_out);
-
-            mlp_out = ggml_add_inplace(ctx0, mlp_out, tfm_layer.mlp_lin2_b);
-
-            queries = ggml_add_inplace(ctx0, queries, mlp_out);
-            queries = ggml_norm_inplace(ctx0, queries, hparams.eps_decoder_transformer);
-            queries = ggml_add_inplace(ctx0,
-                    ggml_mul(ctx0, queries, tfm_layer.norm3_w),
-                    tfm_layer.norm3_b);
-
-            // Cross attention block, image embedding attending to tokens
-            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L175
-            struct ggml_tensor * q_2 = ggml_add(ctx0, queries, tokens);
-            struct ggml_tensor * k_2 = ggml_add(ctx0, keys, pos_src);
-
-            struct ggml_tensor * cross_attn_img_to_token = sam_decode_mask_transformer_attn(tfm_layer.cross_attn_img_to_token, k_2, q_2, queries, ctx0, model);
-            keys = ggml_add_inplace(ctx0, keys, cross_attn_img_to_token);
-            keys = ggml_norm_inplace(ctx0, keys, hparams.eps_decoder_transformer);
-            keys = ggml_add_inplace(ctx0,
-                    ggml_mul(ctx0, keys, tfm_layer.norm4_w),
-                    tfm_layer.norm4_b);
-        }
-
-        // Apply the final attention layer from the points to the image
-        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L99
-        struct ggml_tensor * q = ggml_add(ctx0, queries, tokens);
-        struct ggml_tensor * k = ggml_add(ctx0, keys, pos_src);
-
-        struct ggml_tensor * final_attn_token_to_img = sam_decode_mask_transformer_attn(dec.transformer_final_attn_token_to_img, q, k, keys, ctx0, model);
-
-        queries = ggml_add_inplace(ctx0, queries, final_attn_token_to_img);
-        queries = ggml_norm_inplace(ctx0, queries, hparams.eps_decoder_transformer);
-        queries = ggml_add_inplace(ctx0,
-                ggml_mul(ctx0, queries, dec.transformer_norm_final_w),
-                dec.transformer_norm_final_b);
-    }
-
-
-    struct ggml_tensor * iou_pred = ggml_view_2d(ctx0, queries, queries->ne[0], queries->ne[2], queries->nb[2], 0);
-    const int num_mask_tokens = 4; // num_multimask_outputs + 1
-    struct ggml_tensor * mask_tokens_out = ggml_view_3d(ctx0, queries, queries->ne[0], num_mask_tokens, queries->ne[2], queries->nb[1], num_mask_tokens*queries->nb[1], queries->nb[1]);
-
-    // Upscale mask embeddings and predict masks using the mask tokens
-    // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L136
-    keys = ggml_cont(ctx0, ggml_transpose(ctx0, keys));
-    keys = ggml_view_4d(ctx0, keys, srcNE[0], srcNE[1], srcNE[2], srcNE[3], srcNE[0]*keys->nb[0], keys->nb[1], keys->nb[2], 0);
-    // ggml_build_forward_expand(gf, keys);
-    struct ggml_tensor * upscaled_embedding = {};
-    {
-        // ConvTranspose2d
-        keys = ggml_conv_transpose_2d_p0(ctx0, dec.output_upscaling_0_w, keys, 2);
-        keys = ggml_add_inplace(ctx0, keys, ggml_repeat(ctx0,
-                                     ggml_reshape_3d(ctx0, dec.output_upscaling_0_b, 1, 1, dec.output_upscaling_0_b->ne[0]),
-                                     keys));
-
-        keys = sam_layer_norm_2d(ctx0, keys, n_img_embd, dec.output_upscaling_1_w, dec.output_upscaling_1_b, hparams.eps);
-
-        // GELU activation
-        keys = ggml_gelu_inplace(ctx0, keys);
-
-        // ConvTranspose2d
-        keys = ggml_conv_transpose_2d_p0(ctx0, dec.output_upscaling_3_w, keys, 2);
-        keys = ggml_add_inplace(ctx0, ggml_repeat(ctx0,
-                                ggml_reshape_3d(ctx0, dec.output_upscaling_3_b, 1, 1, dec.output_upscaling_3_b->ne[0]),
-                                keys), keys);
-        // GELU activation
-        keys = ggml_gelu_inplace(ctx0, keys);
-        upscaled_embedding = ggml_reshape_3d(ctx0, keys, keys->ne[0]*keys->ne[1], keys->ne[2], keys->ne[3]);
-        upscaled_embedding = ggml_cont(ctx0, ggml_transpose(ctx0, upscaled_embedding)); // TODO: Shouldn't be needed
-    }
-
-    struct ggml_tensor * hyper_in = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, n_img_embd/2, num_mask_tokens, mask_tokens_out->ne[2]);
-
-    for (int i = 0; i < num_mask_tokens; ++i) {
-        const auto& mlp = dec.output_hypernet_mlps[i];
-        struct ggml_tensor * in = ggml_view_2d(ctx0, mask_tokens_out, mask_tokens_out->ne[0], mask_tokens_out->ne[2], mask_tokens_out->nb[1], i*mask_tokens_out->nb[1]);
-        struct ggml_tensor * out = sam_decode_mask_mlp_relu_3(in, mlp.w_0, mlp.b_0, mlp.w_1, mlp.b_1, mlp.w_2, mlp.b_2, ctx0);
-        ggml_build_forward_expand(gf, ggml_cpy(ctx0, out, ggml_view_2d(ctx0, hyper_in, hyper_in->ne[0], hyper_in->ne[2], hyper_in->nb[1], i*hyper_in->nb[1])));
-    }
-
-    struct ggml_tensor * masks = ggml_mul_mat(ctx0, hyper_in, upscaled_embedding);
-    masks = ggml_cont(ctx0, ggml_transpose(ctx0, masks)); // TODO: Shouldn't be needed
-    masks = ggml_reshape_4d(ctx0, masks, keys->ne[0], keys->ne[1], masks->ne[1], keys->ne[3]);
-
-    // Generate mask quality predictions
-    // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L146
-    iou_pred = sam_decode_mask_mlp_relu_3(iou_pred, dec.iou_prediction_head_0_w, dec.iou_prediction_head_0_b, dec.iou_prediction_head_1_w, dec.iou_prediction_head_1_b, dec.iou_prediction_head_2_w, dec.iou_prediction_head_2_b, ctx0);
-
-    // Select the correct mask or masks for output
-    // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L101
-    iou_pred = ggml_cpy(state.ctx, ggml_view_1d(ctx0, iou_pred, iou_pred->ne[0] - 1, iou_pred->nb[0]), state.iou_predictions);
-    masks = ggml_view_4d(ctx0, masks, masks->ne[0], masks->ne[1], masks->ne[2] - 1, masks->ne[3],
-                                      masks->nb[1], masks->nb[2], masks->nb[3], masks->nb[2] /* offset*/);
-    masks = ggml_cpy(state.ctx, masks, state.low_res_masks);
-
-    ggml_build_forward_expand(gf, masks);
-    ggml_build_forward_expand(gf, iou_pred);
-
-    ggml_disconnect_node_from_graph(state.low_res_masks);
-    ggml_disconnect_node_from_graph(state.iou_predictions);
-
-    return true;
-}
-
-bool sam_write_masks(const sam_hparams& hparams, int nx, int ny, const sam_state & state, const std::string & fname) {
-    if (state.low_res_masks->ne[2] == 0) return true;
-    if (state.low_res_masks->ne[2] != state.iou_predictions->ne[0]) {
-        printf("Error: number of masks (%d) does not match number of iou predictions (%d)\n", (int)state.low_res_masks->ne[2], (int)state.iou_predictions->ne[0]);
-        return false;
-    }
-
-    const int n_img_size = hparams.n_img_size();
-    const float mask_threshold = hparams.mask_threshold;
-    const float iou_threshold = hparams.iou_threshold;
-    const float stability_score_threshold = hparams.stability_score_threshold;
-    const float intersection_threshold = mask_threshold + hparams.stability_score_offset;
-    const float union_threshold = mask_threshold - hparams.stability_score_offset;
-
-    const int ne0 = state.low_res_masks->ne[0];
-    const int ne1 = state.low_res_masks->ne[1];
-    const int ne2 = state.low_res_masks->ne[2];
-
-    // Remove padding and upscale masks to the original image size.
-    // ref: https://github.com/facebookresearch/segment-anything/blob/efeab7296ab579d4a261e554eca80faf6b33924a/segment_anything/modeling/sam.py#L140
-
-    const float preprocess_scale = std::max(nx, ny) / float(n_img_size);
-    const int cropped_nx = int(nx / preprocess_scale + 0.5f);
-    const int cropped_ny = int(ny / preprocess_scale + 0.5f);
-
-    const float scale_x_1 = (float)ne0 / (float)n_img_size;
-    const float scale_y_1 = (float)ne1 / (float)n_img_size;
-
-    const float scale_x_2 = float(cropped_nx) / float(nx);
-    const float scale_y_2 = float(cropped_ny) / float(ny);
-
-    const auto iou_data = (float*)state.iou_predictions->data;
-
-    for (int i = 0; i < ne2; ++i) {
-        if (iou_threshold > 0.f && iou_data[i] < iou_threshold) {
-            printf("Skipping mask %d with iou %f below threshold %f\n", i, iou_data[i], iou_threshold);
-            continue; // Filtering masks with iou below the threshold
-        }
-
-        std::vector<float> mask_data(n_img_size*n_img_size);
-        {
-            const float* data = (float *) state.low_res_masks->data + i*ne0*ne1;
-
-            for (int iy = 0; iy < n_img_size; ++iy) {
-                for (int ix = 0; ix < n_img_size; ++ix) {
-                    const float sx = std::max(scale_x_1*(ix + 0.5f) - 0.5f, 0.0f);
-                    const float sy = std::max(scale_y_1*(iy + 0.5f) - 0.5f, 0.0f);
-
-                    const int x0 = std::max(0, (int)sx);
-                    const int y0 = std::max(0, (int)sy);
-
-                    const int x1 = std::min(x0 + 1, ne0 - 1);
-                    const int y1 = std::min(y0 + 1, ne1 - 1);
-
-                    const float dx = sx - x0;
-                    const float dy = sy - y0;
-
-                    const int j00 = y0*ne0 + x0;
-                    const int j01 = y0*ne0 + x1;
-                    const int j10 = y1*ne0 + x0;
-                    const int j11 = y1*ne0 + x1;
-
-                    const float v00 = data[j00];
-                    const float v01 = data[j01];
-                    const float v10 = data[j10];
-                    const float v11 = data[j11];
-
-                    const float v0 = (1-dx)*v00 + dx*v01;
-                    const float v1 = (1-dx)*v10 + dx*v11;
-
-                    const float v = (1-dy)*v0 + dy*v1;
-
-                    mask_data[iy*n_img_size + ix] = v;
-                }
-            }
-        }
-
-        int intersections = 0;
-        int unions = 0;
-        sam_image_u8 res;
-        int min_iy = ny;
-        int max_iy = 0;
-        int min_ix = nx;
-        int max_ix = 0;
-        {
-            const float* data = mask_data.data();
-
-            res.nx = nx;
-            res.ny = ny;
-            res.data.resize(nx*ny);
-
-            for (int iy = 0; iy < ny; ++iy) {
-                for (int ix = 0; ix < nx; ++ix) {
-                    const float sx = std::max(scale_x_2*(ix + 0.5f) - 0.5f, 0.0f);
-                    const float sy = std::max(scale_y_2*(iy + 0.5f) - 0.5f, 0.0f);
-
-                    const int x0 = std::max(0, (int)sx);
-                    const int y0 = std::max(0, (int)sy);
-
-                    const int x1 = std::min(x0 + 1, cropped_nx - 1);
-                    const int y1 = std::min(y0 + 1, cropped_ny - 1);
-
-                    const float dx = sx - x0;
-                    const float dy = sy - y0;
-
-                    const int j00 = y0*n_img_size + x0;
-                    const int j01 = y0*n_img_size + x1;
-                    const int j10 = y1*n_img_size + x0;
-                    const int j11 = y1*n_img_size + x1;
-
-                    const float v00 = data[j00];
-                    const float v01 = data[j01];
-                    const float v10 = data[j10];
-                    const float v11 = data[j11];
-
-                    const float v0 = (1-dx)*v00 + dx*v01;
-                    const float v1 = (1-dx)*v10 + dx*v11;
-
-                    const float v = (1-dy)*v0 + dy*v1;
-
-                    if (v > intersection_threshold) {
-                        intersections++;
-                    }
-                    if (v > union_threshold) {
-                        unions++;
-                    }
-                    if (v > mask_threshold) {
-                        min_iy = std::min(min_iy, iy);
-                        max_iy = std::max(max_iy, iy);
-                        min_ix = std::min(min_ix, ix);
-                        max_ix = std::max(max_ix, ix);
-
-                        res.data[iy*nx + ix] = 255;
-                    }
-                }
-            }
-        }
-
-        const float stability_score = float(intersections) / float(unions);
-        if (stability_score_threshold > 0.f && stability_score < stability_score_threshold) {
-            printf("Skipping mask %d with stability score %f below threshold %f\n", i, stability_score, stability_score_threshold);
-            continue; // Filtering masks with stability score below the threshold
-        }
-
-        printf("Mask %d: iou = %f, stability_score = %f, bbox (%d, %d), (%d, %d)\n",
-                i, iou_data[i], stability_score, min_ix, max_ix, min_iy, max_iy);
-
-        std::string filename = fname + std::to_string(i) + ".png";
-        if (!stbi_write_png(filename.c_str(), res.nx, res.ny, 1, res.data.data(), res.nx)) {
-            printf("%s: failed to write mask %s\n", __func__, filename.c_str());
-            return false;
-        }
-    }
-
-
-    return true;
-}
-
-struct ggml_cgraph  * sam_build_fast_graph(
-        const sam_model     & model,
-                  sam_state & state,
-                        int   nx,
-                        int   ny,
-                  sam_point   point) {
-
-    struct ggml_init_params ggml_params = {
-        /*.mem_size   =*/ state.buf_compute_fast.size(),
-        /*.mem_buffer =*/ state.buf_compute_fast.data(),
-        /*.no_alloc   =*/ true, // skip allocating as we use ggml_alloc to allocate exact memory requirements
-    };
-
-    struct ggml_context * ctx0   = ggml_init(ggml_params);
-    struct ggml_cgraph  * gf     = ggml_new_graph(ctx0);
-
-    prompt_encoder_result enc_res = sam_encode_prompt(model, ctx0, gf, state);
-    if (!enc_res.embd_prompt_sparse || !enc_res.embd_prompt_dense) {
-        fprintf(stderr, "%s: failed to encode prompt (%f, %f)\n", __func__, point.x, point.y);
-        return {};
-    }
-
-    struct ggml_tensor * pe_img_dense = sam_fill_dense_pe(model, ctx0, gf, state);
-    if (!pe_img_dense) {
-        fprintf(stderr, "%s: failed to get dense positional encoding\n", __func__);
-        return {};
-    }
-
-    if (!sam_decode_mask(model, enc_res, pe_img_dense, ctx0, gf, state)) {
-         fprintf(stderr, "%s: failed to decode mask\n", __func__);
-         return {};
-    }
-
-    ggml_free(ctx0);
-
-    ggml_gallocr_alloc_graph(state.allocr, gf);
-
-    // from sam_encode_prompt
-    {
-        // transform points
-        // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/automatic_mask_generator.py#L276
-        {
-            const int nmax = std::max(nx, ny);
-
-            const float scale = model.hparams.n_img_size() / (float) nmax;
-
-            const int nx_new = int(nx*scale + 0.5f);
-            const int ny_new = int(ny*scale + 0.5f);
-
-            point.x = point.x*(float(nx_new)/nx) + 0.5f;
-            point.y = point.y*(float(ny_new)/ny) + 0.5f;
-        }
-
-        struct ggml_tensor * inp = ggml_graph_get_tensor(gf, "prompt_input");
-        // set the input by converting the [0, 1] coordinates to [-1, 1]
-        float * data = (float *) inp->data;
-
-        data[0] = 2.0f*(point.x / model.hparams.n_img_size()) - 1.0f;
-        data[1] = 2.0f*(point.y / model.hparams.n_img_size()) - 1.0f;
-
-        // padding
-        // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L81-L85
-        data[2] = 2.0f*(0.0f) - 1.0f;
-        data[3] = 2.0f*(0.0f) - 1.0f;
-    }
-
-    // from sam_fill_dense_pe
-    {
-        struct ggml_tensor * xy_embed_stacked = ggml_graph_get_tensor(gf, "xy_embed_stacked");
-        const int32_t n_img_embd = model.hparams.n_img_embd();
-        const float n_img_embd_inv = 1.0f / n_img_embd;
-        float * data = (float *) ggml_get_data(xy_embed_stacked);
-        for (int i = 0; i < n_img_embd; ++i) {
-            const int row = 2*i*n_img_embd;
-            const float y_val = 2 * (i + 0.5f) * n_img_embd_inv - 1;
-            for (int j = 0; j < n_img_embd; ++j) {
-                const float x_val = 2 * (j + 0.5f) * n_img_embd_inv - 1;
-                data[row + 2*j + 0] = x_val;
-                data[row + 2*j + 1] = y_val;
-            }
-        }
-    }
-
-    return gf;
-}
-
-void sam_print_usage(int argc, char ** argv, const sam_params & params) {
-    fprintf(stderr, "usage: %s [options]\n", argv[0]);
-    fprintf(stderr, "\n");
-    fprintf(stderr, "options:\n");
-    fprintf(stderr, "  -h, --help            show this help message and exit\n");
-    fprintf(stderr, "  -s SEED, --seed SEED  RNG seed (default: -1)\n");
-    fprintf(stderr, "  -t N, --threads N     number of threads to use during computation (default: %d)\n", params.n_threads);
-    fprintf(stderr, "  -m FNAME, --model FNAME\n");
-    fprintf(stderr, "                        model path (default: %s)\n", params.model.c_str());
-    fprintf(stderr, "  -i FNAME, --inp FNAME\n");
-    fprintf(stderr, "                        input file (default: %s)\n", params.fname_inp.c_str());
-    fprintf(stderr, "  -o FNAME, --out FNAME\n");
-    fprintf(stderr, "                        mask file name prefix (default: %s)\n", params.fname_out.c_str());
-    fprintf(stderr, "SAM hyperparameters:\n");
-    fprintf(stderr, "  -mt FLOAT, --mask-threshold\n");
-    fprintf(stderr, "                        mask threshold (default: %f)\n", params.mask_threshold);
-    fprintf(stderr, "  -it FLOAT, --iou-threshold\n");
-    fprintf(stderr, "                        iou threshold (default: %f)\n", params.iou_threshold);
-    fprintf(stderr, "  -st FLOAT, --score-threshold\n");
-    fprintf(stderr, "                        score threshold (default: %f)\n", params.stability_score_threshold);
-    fprintf(stderr, "  -so FLOAT, --score-offset\n");
-    fprintf(stderr, "                        score offset (default: %f)\n", params.stability_score_offset);
-    fprintf(stderr, "  -e FLOAT, --epsilon\n");
-    fprintf(stderr, "                        epsilon (default: %f)\n", params.eps);
-    fprintf(stderr, "  -ed FLOAT, --epsilon-decoder-transformer\n");
-    fprintf(stderr, "                        epsilon decoder transformer (default: %f)\n", params.eps_decoder_transformer);
-    fprintf(stderr, "SAM prompt:\n");
-    fprintf(stderr, "  -p TUPLE, --point-prompt\n");
-    fprintf(stderr, "                        point to be used as prompt for SAM (default: %f,%f). Must be in a format FLOAT,FLOAT \n", params.pt.x, params.pt.y);
-    fprintf(stderr, "\n");
-}
-
-bool sam_params_parse(int argc, char ** argv, sam_params & params) {
-    for (int i = 1; i < argc; i++) {
-        std::string arg = argv[i];
-
-        if (arg == "-s" || arg == "--seed") {
-            params.seed = std::stoi(argv[++i]);
-        } else if (arg == "-t" || arg == "--threads") {
-            params.n_threads = std::stoi(argv[++i]);
-        } else if (arg == "-m" || arg == "--model") {
-            params.model = argv[++i];
-        } else if (arg == "-i" || arg == "--inp") {
-            params.fname_inp = argv[++i];
-        } else if (arg == "-o" || arg == "--out") {
-            params.fname_out = argv[++i];
-        } else if (arg == "-mt" || arg == "--mask-threshold") {
-            params.mask_threshold = std::stof(argv[++i]);
-        } else if (arg == "-it" || arg == "--iou-threshold") {
-            params.iou_threshold = std::stof(argv[++i]);
-        } else if (arg == "-st" || arg == "--score-threshold") {
-            params.stability_score_threshold = std::stof(argv[++i]);
-        } else if (arg == "-so" || arg == "--score-offset") {
-            params.stability_score_offset = std::stof(argv[++i]);
-        } else if (arg == "-e" || arg == "--epsilon") {
-            params.eps = std::stof(argv[++i]);
-        } else if (arg == "-ed" || arg == "--epsilon-decoder-transformer") {
-            params.eps_decoder_transformer = std::stof(argv[++i]);
-        } else if (arg == "-p" || arg == "--point-prompt") {
-            // TODO multiple points per model invocation
-            char* point = argv[++i];
-
-            char* coord = strtok(point, ",");
-            if (!coord){
-                fprintf(stderr, "Error while parsing prompt!\n");
-                exit(1);
-            }
-            params.pt.x = std::stof(coord);
-            coord = strtok(NULL, ",");
-            if (!coord){
-                fprintf(stderr, "Error while parsing prompt!\n");
-                exit(1);
-            }
-            params.pt.y = std::stof(coord);
-        } else if (arg == "-h" || arg == "--help") {
-            sam_print_usage(argc, argv, params);
-            exit(0);
-        } else {
-            fprintf(stderr, "error: unknown argument: %s\n", arg.c_str());
-            sam_print_usage(argc, argv, params);
-            exit(0);
-        }
-    }
-
-    return true;
-}
-
-int main(int argc, char ** argv) {
-    const int64_t t_main_start_us = ggml_time_us();
-
-    sam_params params;
-    params.model = "models/sam-vit-b/ggml-model-f16.bin";
-
-    sam_model model;
-    sam_state state;
-    int64_t t_load_us = 0;
-
-    if (sam_params_parse(argc, argv, params) == false) {
-        return 1;
-    }
-
-    if (params.seed < 0) {
-        params.seed = time(NULL);
-    }
-    fprintf(stderr, "%s: seed = %d\n", __func__, params.seed);
-
-    // load the image
-    sam_image_u8 img0;
-    if (!sam_image_load_from_file(params.fname_inp, img0)) {
-        fprintf(stderr, "%s: failed to load image from '%s'\n", __func__, params.fname_inp.c_str());
-        return 1;
-    }
-    fprintf(stderr, "%s: loaded image '%s' (%d x %d)\n", __func__, params.fname_inp.c_str(), img0.nx, img0.ny);
-
-    // preprocess to f32
-    sam_image_f32 img1;
-    if (!sam_image_preprocess(img0, img1)) {
-        fprintf(stderr, "%s: failed to preprocess image\n", __func__);
-        return 1;
-    }
-    fprintf(stderr, "%s: preprocessed image (%d x %d)\n", __func__, img1.nx, img1.ny);
-
-
-    // load the model
-    {
-        const int64_t t_start_us = ggml_time_us();
-
-        if (!sam_model_load(params, model)) {
-            fprintf(stderr, "%s: failed to load model from '%s'\n", __func__, params.model.c_str());
-            return 1;
-        }
-
-        t_load_us = ggml_time_us() - t_start_us;
-    }
-
-    {
-        static size_t buf_size = 256u*1024*1024;
-
-        struct ggml_init_params ggml_params = {
-            /*.mem_size   =*/ buf_size,
-            /*.mem_buffer =*/ NULL,
-            /*.no_alloc   =*/ false,
-        };
-
-        state.ctx = ggml_init(ggml_params);
-
-        state.embd_img = ggml_new_tensor_3d(state.ctx, GGML_TYPE_F32,
-                model.hparams.n_img_embd(), model.hparams.n_img_embd(), model.hparams.n_enc_out_chans);
-
-        state.low_res_masks = ggml_new_tensor_3d(state.ctx, GGML_TYPE_F32,
-                model.hparams.n_enc_out_chans, model.hparams.n_enc_out_chans, 3);
-
-        state.iou_predictions = ggml_new_tensor_1d(state.ctx, GGML_TYPE_F32, 3);
-    }
-
-
-    {
-        state.buf_compute_img_enc.resize(ggml_tensor_overhead()*GGML_DEFAULT_GRAPH_SIZE + ggml_graph_overhead());
-        state.allocr = ggml_gallocr_new(ggml_backend_cpu_buffer_type());
-
-        struct ggml_cgraph  * gf = sam_encode_image(model, state, img1);
-        if (!gf) {
-            fprintf(stderr, "%s: failed to encode image\n", __func__);
-            return 1;
-        }
-
-        ggml_graph_compute_helper(state.work_buffer, gf, params.n_threads);
-
-        print_t_f32("embd_img", state.embd_img);
-
-        ggml_gallocr_free(state.allocr);
-        state.allocr = NULL;
-        state.work_buffer.clear();
-    }
-    {
-        state.buf_compute_fast.resize(ggml_tensor_overhead()*GGML_DEFAULT_GRAPH_SIZE + ggml_graph_overhead());
-        state.allocr = ggml_gallocr_new(ggml_backend_cpu_buffer_type());
-
-        // TODO: more varied prompts
-        fprintf(stderr, "prompt: (%f, %f)\n", params.pt.x, params.pt.y);
-
-        struct ggml_cgraph  * gf = sam_build_fast_graph(model, state, img0.nx, img0.ny, params.pt);
-        if (!gf) {
-            fprintf(stderr, "%s: failed to build fast graph\n", __func__);
-            return 1;
-        }
-
-        ggml_graph_compute_helper(state.work_buffer, gf, params.n_threads);
-
-        //print_t_f32("iou_predictions", state.iou_predictions);
-        //print_t_f32("low_res_masks", state.low_res_masks);
-        ggml_gallocr_free(state.allocr);
-        state.allocr = NULL;
-    }
-
-    if (!sam_write_masks(model.hparams, img0.nx, img0.ny, state, params.fname_out)) {
-        fprintf(stderr, "%s: failed to write masks\n", __func__);
-        return 1;
-    }
-
-    // report timing
-    {
-        const int64_t t_main_end_us = ggml_time_us();
-
-        fprintf(stderr, "\n\n");
-        fprintf(stderr, "%s:     load time = %8.2f ms\n", __func__, t_load_us/1000.0f);
-        fprintf(stderr, "%s:    total time = %8.2f ms\n", __func__, (t_main_end_us - t_main_start_us)/1000.0f);
-    }
-
-    ggml_free(model.ctx);
-
-    return 0;
-}
diff --git a/examples/sam/sam.cpp b/examples/sam/sam.cpp
new file mode 100644 (file)
index 0000000..299318f
--- /dev/null
@@ -0,0 +1,2365 @@
+#define _USE_MATH_DEFINES // for M_PI
+#define _CRT_SECURE_NO_DEPRECATE // Disables ridiculous "unsafe" warnigns on Windows
+
+#include "ggml.h"
+#include "ggml-cpu.h"
+#include "ggml-alloc.h"
+#include "ggml-backend.h"
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include "stb_image_write.h"
+
+#include <cassert>
+#include <cmath>
+#include <cstddef>
+#include <cstdio>
+#include <cstring>
+#include <fstream>
+#include <map>
+#include <string>
+#include <vector>
+#include <thread>
+#include <cinttypes>
+
+#if defined(_MSC_VER)
+#pragma warning(disable: 4244 4267) // possible loss of data
+#endif
+
+// default hparams (ViT-B SAM)
+struct sam_hparams {
+    int32_t n_enc_state               = 768;
+    int32_t n_enc_layer               = 12;
+    int32_t n_enc_head                = 12;
+    int32_t n_enc_out_chans           = 256;
+    int32_t n_pt_embd                 = 4;
+    int32_t n_dec_heads               = 8;
+    int32_t ftype                     = 1;
+    float   mask_threshold            = 0.f;
+    float   iou_threshold             = 0.88f;
+    float   stability_score_threshold = 0.95f;
+    float   stability_score_offset    = 1.0f;
+    float   eps                       = 1e-6f;
+    float   eps_decoder_transformer   = 1e-5f;
+
+    int32_t n_enc_head_dim() const { return n_enc_state / n_enc_head; }
+    int32_t n_img_size()     const { return 1024; }
+    int32_t n_window_size()  const { return 14; }
+    int32_t n_patch_size()   const { return 16; }
+    int32_t n_img_embd()     const { return n_img_size() / n_patch_size(); }
+
+    std::vector<int32_t> global_attn_indices() const {
+        switch (n_enc_state) {
+            case  768: return {  2,  5,  8, 11 };
+            case 1024: return {  5, 11, 17, 23 };
+            case 1280: return {  7, 15, 23, 31 };
+            default:
+                {
+                    fprintf(stderr, "%s: unsupported n_enc_state = %d\n", __func__, n_enc_state);
+                } break;
+        };
+
+        return {};
+    }
+
+    bool is_global_attn(int32_t layer) const {
+        const auto indices = global_attn_indices();
+
+        for (const auto & idx : indices) {
+            if (layer == idx) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+};
+
+struct sam_layer_enc {
+    struct ggml_tensor * norm1_w;
+    struct ggml_tensor * norm1_b;
+
+    struct ggml_tensor * rel_pos_w;
+    struct ggml_tensor * rel_pos_h;
+
+    struct ggml_tensor * qkv_w;
+    struct ggml_tensor * qkv_b;
+
+    struct ggml_tensor * proj_w;
+    struct ggml_tensor * proj_b;
+
+    struct ggml_tensor * norm2_w;
+    struct ggml_tensor * norm2_b;
+
+    struct ggml_tensor * mlp_lin1_w;
+    struct ggml_tensor * mlp_lin1_b;
+
+    struct ggml_tensor * mlp_lin2_w;
+    struct ggml_tensor * mlp_lin2_b;
+};
+
+struct sam_encoder_image {
+    struct ggml_tensor * pe;
+
+    struct ggml_tensor * proj_w;
+    struct ggml_tensor * proj_b;
+
+    struct ggml_tensor * neck_conv_0;
+    struct ggml_tensor * neck_norm_0_w;
+    struct ggml_tensor * neck_norm_0_b;
+    struct ggml_tensor * neck_conv_1;
+    struct ggml_tensor * neck_norm_1_w;
+    struct ggml_tensor * neck_norm_1_b;
+
+    std::vector<sam_layer_enc> layers;
+};
+
+struct sam_encoder_prompt {
+    struct ggml_tensor * pe;
+
+    struct ggml_tensor * not_a_pt_embd_w;
+    std::vector<struct ggml_tensor *> pt_embd;
+
+    struct ggml_tensor * no_mask_embd_w;
+    //std::vector<struct ggml_tensor *> mask_down_w;
+    //std::vector<struct ggml_tensor *> mask_down_b;
+};
+
+struct  sam_layer_dec_transformer_attn {
+    // q_proj
+    struct ggml_tensor * q_w;
+    struct ggml_tensor * q_b;
+
+    // k_proj
+    struct ggml_tensor * k_w;
+    struct ggml_tensor * k_b;
+
+    // v_proj
+    struct ggml_tensor * v_w;
+    struct ggml_tensor * v_b;
+
+    // out_proj
+    struct ggml_tensor * out_w;
+    struct ggml_tensor * out_b;
+};
+
+struct sam_layer_dec_transformer {
+    sam_layer_dec_transformer_attn self_attn;
+
+    // norm1
+    struct ggml_tensor * norm1_w;
+    struct ggml_tensor * norm1_b;
+
+    sam_layer_dec_transformer_attn cross_attn_token_to_img;
+
+    // norm2
+    struct ggml_tensor * norm2_w;
+    struct ggml_tensor * norm2_b;
+
+    // mlp.lin1
+    struct ggml_tensor * mlp_lin1_w;
+    struct ggml_tensor * mlp_lin1_b;
+
+    // mlp.lin2
+    struct ggml_tensor * mlp_lin2_w;
+    struct ggml_tensor * mlp_lin2_b;
+
+    // norm3
+    struct ggml_tensor * norm3_w;
+    struct ggml_tensor * norm3_b;
+
+    // norm4
+    struct ggml_tensor * norm4_w;
+    struct ggml_tensor * norm4_b;
+
+    sam_layer_dec_transformer_attn cross_attn_img_to_token;
+};
+
+struct sam_layer_dec_output_hypernet_mlps {
+    // mlps_*.layers.0
+    struct ggml_tensor * w_0;
+    struct ggml_tensor * b_0;
+
+    // mlps_*.layers.1
+    struct ggml_tensor * w_1;
+    struct ggml_tensor * b_1;
+
+    // mlps_*.layers.2
+    struct ggml_tensor * w_2;
+    struct ggml_tensor * b_2;
+};
+
+struct sam_decoder_mask {
+    std::vector<sam_layer_dec_transformer> transformer_layers;
+
+    // trasnformer.final_attn_token_to_image
+    sam_layer_dec_transformer_attn transformer_final_attn_token_to_img;
+
+    // transformer.norm_final
+    struct ggml_tensor * transformer_norm_final_w;
+    struct ggml_tensor * transformer_norm_final_b;
+
+    // output_upscaling.0
+    struct ggml_tensor * output_upscaling_0_w;
+    struct ggml_tensor * output_upscaling_0_b;
+
+    // output_upscaling.1
+    struct ggml_tensor * output_upscaling_1_w;
+    struct ggml_tensor * output_upscaling_1_b;
+
+    // output_upscaling.3
+    struct ggml_tensor * output_upscaling_3_w;
+    struct ggml_tensor * output_upscaling_3_b;
+
+    // output_hypernetworks_mlps
+    std::vector<sam_layer_dec_output_hypernet_mlps> output_hypernet_mlps;
+
+    // iou_prediction_head.0
+    struct ggml_tensor * iou_prediction_head_0_w;
+    struct ggml_tensor * iou_prediction_head_0_b;
+
+    // iou_prediction_head.1
+    struct ggml_tensor * iou_prediction_head_1_w;
+    struct ggml_tensor * iou_prediction_head_1_b;
+
+    // iou_prediction_head.2
+    struct ggml_tensor * iou_prediction_head_2_w;
+    struct ggml_tensor * iou_prediction_head_2_b;
+
+    // iou_token.weight
+    struct ggml_tensor * iou_token_w;
+
+    // mask_tokens.weight
+    struct ggml_tensor * mask_tokens_w;
+};
+
+
+struct sam_state {
+    struct ggml_tensor * embd_img;
+
+    struct ggml_tensor * low_res_masks;
+    struct ggml_tensor * iou_predictions;
+
+    //struct ggml_tensor * tmp_save = {};
+
+    struct ggml_context * ctx;
+
+    // buffer for `ggml_graph_plan.work_data`
+    std::vector<uint8_t> work_buffer;
+    // buffers to evaluate the model
+    std::vector<uint8_t> buf_compute_img_enc;
+
+    std::vector<uint8_t> buf_compute_fast;
+
+    ggml_gallocr_t       allocr = {};
+};
+
+// void save_tensor(sam_state& state, struct ggml_tensor * t, struct ggml_cgraph * gf) {
+//     if (!state.tmp_save) {
+//         state.tmp_save = ggml_new_tensor(state.ctx, t->type, t->n_dims, t->ne);
+//     }
+//     struct ggml_tensor * tmp0 = ggml_cpy(state.ctx, t, state.tmp_save);
+//     ggml_build_forward_expand(gf, tmp0);
+// }
+
+struct sam_model {
+    sam_hparams hparams;
+
+    sam_encoder_image  enc_img;
+    sam_encoder_prompt enc_prompt;
+    sam_decoder_mask   dec;
+
+    //
+    struct ggml_context * ctx;
+    std::map<std::string, struct ggml_tensor *> tensors;
+};
+
+struct sam_point {
+    float x;
+    float y;
+};
+
+struct sam_box {
+    float x1;
+    float y1;
+    float x2;
+    float y2;
+};
+
+// RGB uint8 image
+struct sam_image_u8 {
+    int nx;
+    int ny;
+
+    std::vector<uint8_t> data;
+};
+
+// RGB float32 image
+// Memory layout: RGBRGBRGB...
+struct sam_image_f32 {
+    int nx;
+    int ny;
+
+    std::vector<float> data;
+};
+
+enum sam_prompt_type {
+    SAM_PROMPT_TYPE_POINT = 0,
+    SAM_PROMPT_TYPE_BOX = 1,
+};
+
+struct sam_prompt {
+    sam_prompt_type prompt_type = SAM_PROMPT_TYPE_POINT;
+    sam_point pt = { 414.375f, 162.796875f, };
+    sam_box   box = { 368.0f, 144.0f, 441.0f, 173.0f };
+};
+
+struct sam_params {
+    int32_t seed      = -1; // RNG seed
+    int32_t n_threads = std::min(4, (int32_t) std::thread::hardware_concurrency());
+
+    std::string model     = "models/sam-vit-b/ggml-model-f16.bin"; // model path
+    std::string fname_inp = "img.jpg";
+    std::string fname_out = "img.out";
+    float   mask_threshold            = 0.f;
+    float   iou_threshold             = 0.88f;
+    float   stability_score_threshold = 0.95f;
+    float   stability_score_offset    = 1.0f;
+    float   eps                       = 1e-6f;
+    float   eps_decoder_transformer   = 1e-5f;
+
+    sam_prompt prompt;
+    bool multimask_output = true;
+};
+
+void print_t_f32(const char* title, struct ggml_tensor * t, int n = 10) {
+    printf("%s\n", title);
+    float * data = (float *)t->data;
+    printf("dims: % " PRId64 " % " PRId64 " % " PRId64 " % " PRId64 " f32\n", t->ne[0], t->ne[1], t->ne[2], t->ne[3]);
+    printf("First & Last %d elements:\n", n);
+    for (int i = 0; i < std::min((int) (t->ne[0]*t->ne[1]), n); i++) {
+        printf("%.5f ", data[i]);
+        if (i != 0 && i % t->ne[0] == 0) {
+            printf("\n");
+        }
+    }
+    printf("\n");
+    for (int i = 0; i < std::min((int) (t->ne[0]*t->ne[1]), n); i++) {
+        printf("%.5f ", data[ggml_nelements(t) - n + i]);
+        if ((ggml_nelements(t) - n + i) % t->ne[0] == 0) {
+            printf("\n");
+        }
+    }
+    printf("\n");
+    double sum = 0.0;
+    for (int i = 0; i < ggml_nelements(t); i++) {
+        sum += data[i];
+    }
+    printf("sum:  %f\n\n", sum);
+}
+
+static void ggml_disconnect_node_from_graph(ggml_tensor * t) {
+    t->op = GGML_OP_NONE;
+    for (int i = 0; i < GGML_MAX_SRC; i++) {
+        t->src[i] = NULL;
+    }
+}
+
+static void ggml_graph_compute_helper(std::vector<uint8_t> & buf, ggml_cgraph * graph, int n_threads) {
+    struct ggml_cplan plan = ggml_graph_plan(graph, n_threads, nullptr);
+
+    if (plan.work_size > 0) {
+        buf.resize(plan.work_size);
+        plan.work_data = buf.data();
+    }
+
+    ggml_graph_compute(graph, &plan);
+}
+
+static void ggml_sam_sin(struct ggml_tensor * dst , const struct ggml_tensor * src, int ith, int nth, void * userdata) {
+    GGML_ASSERT(userdata == NULL);
+    GGML_ASSERT(ggml_are_same_shape(dst, src));
+    GGML_ASSERT(ggml_is_contiguous(dst));
+    GGML_ASSERT(ggml_is_contiguous(src));
+
+    const float * src_data = ggml_get_data_f32(src);
+    float * dst_data = ggml_get_data_f32(dst);
+
+    const int ne = (int)ggml_nelements(dst);
+    const int dr = (ne + nth - 1) / nth;
+    const int ie0 = dr * ith;
+    const int ie1 = std::min(ie0 + dr, ne);
+
+    for (int i = ie0; i < ie1; ++i) {
+        dst_data[i] = sinf(src_data[i]);
+    }
+}
+
+static void ggml_sam_cos(struct ggml_tensor * dst , const struct ggml_tensor * src, int ith, int nth, void * userdata) {
+    GGML_ASSERT(userdata == NULL);
+    GGML_ASSERT(ggml_are_same_shape(dst, src));
+    GGML_ASSERT(ggml_is_contiguous(dst));
+    GGML_ASSERT(ggml_is_contiguous(src));
+
+    const float * src_data = ggml_get_data_f32(src);
+    float * dst_data = ggml_get_data_f32(dst);
+
+    const int ne = (int)ggml_nelements(dst);
+    const int dr = (ne + nth - 1) / nth;
+    const int ie0 = dr * ith;
+    const int ie1 = std::min(ie0 + dr, ne);
+
+    for (int i = ie0; i < ie1; ++i) {
+        dst_data[i] = cosf(src_data[i]);
+    }
+}
+
+bool sam_image_load_from_file(const std::string & fname, sam_image_u8 & img) {
+    int nx, ny, nc;
+    auto data = stbi_load(fname.c_str(), &nx, &ny, &nc, 3);
+    if (!data) {
+        fprintf(stderr, "%s: failed to load '%s'\n", __func__, fname.c_str());
+        return false;
+    }
+
+    img.nx = nx;
+    img.ny = ny;
+    img.data.resize(nx * ny * 3);
+    memcpy(img.data.data(), data, nx * ny * 3);
+
+    stbi_image_free(data);
+
+    return true;
+}
+
+// ref: https://github.com/facebookresearch/segment-anything/blob/efeab7296ab579d4a261e554eca80faf6b33924a/segment_anything/modeling/sam.py#L164
+// resize largest dimension to 1024
+// normalize: x = (x - mean) / std
+//     mean = [123.675, 116.28, 103.53]
+//     std  = [58.395, 57.12, 57.375]
+//     TODO: why are these hardcoded !?
+// pad to 1024x1024
+// TODO: for some reason, this is not numerically identical to pytorch's interpolation
+bool sam_image_preprocess(const sam_image_u8 & img, sam_image_f32 & res) {
+    const int nx = img.nx;
+    const int ny = img.ny;
+
+    const int nx2 = 1024;
+    const int ny2 = 1024;
+
+    res.nx = nx2;
+    res.ny = ny2;
+    res.data.resize(3*nx2*ny2);
+
+    const float scale = std::max(nx, ny) / 1024.0f;
+
+    fprintf(stderr, "%s: scale = %f\n", __func__, scale);
+
+    const int nx3 = int(nx/scale + 0.5f);
+    const int ny3 = int(ny/scale + 0.5f);
+
+    const float m3[3] = { 123.675f, 116.280f, 103.530f };
+    const float s3[3] = {  58.395f,  57.120f,  57.375f };
+
+    for (int y = 0; y < ny3; y++) {
+        for (int x = 0; x < nx3; x++) {
+            for (int c = 0; c < 3; c++) {
+                // linear interpolation
+                const float sx = (x + 0.5f)*scale - 0.5f;
+                const float sy = (y + 0.5f)*scale - 0.5f;
+
+                const int x0 = std::max(0, (int) std::floor(sx));
+                const int y0 = std::max(0, (int) std::floor(sy));
+
+                const int x1 = std::min(x0 + 1, nx - 1);
+                const int y1 = std::min(y0 + 1, ny - 1);
+
+                const float dx = sx - x0;
+                const float dy = sy - y0;
+
+                const int j00 = 3*(y0*nx + x0) + c;
+                const int j01 = 3*(y0*nx + x1) + c;
+                const int j10 = 3*(y1*nx + x0) + c;
+                const int j11 = 3*(y1*nx + x1) + c;
+
+                const float v00 = img.data[j00];
+                const float v01 = img.data[j01];
+                const float v10 = img.data[j10];
+                const float v11 = img.data[j11];
+
+                const float v0 = v00*(1.0f - dx) + v01*dx;
+                const float v1 = v10*(1.0f - dx) + v11*dx;
+
+                const float v = v0*(1.0f - dy) + v1*dy;
+
+                const uint8_t v2 = std::min(std::max(std::round(v), 0.0f), 255.0f);
+
+                const int i = 3*(y*nx3 + x) + c;
+
+                res.data[i] = (float(v2) - m3[c]) / s3[c];
+            }
+        }
+    }
+
+    return true;
+}
+
+// load the model's weights from a file
+bool sam_model_load(const sam_params & params, sam_model & model) {
+    fprintf(stderr, "%s: loading model from '%s' - please wait ...\n", __func__, params.model.c_str());
+
+    auto fin = std::ifstream(params.model, std::ios::binary);
+    if (!fin) {
+        fprintf(stderr, "%s: failed to open '%s'\n", __func__, params.model.c_str());
+        return false;
+    }
+
+    // verify magic
+    {
+        uint32_t magic;
+        fin.read((char *) &magic, sizeof(magic));
+        if (magic != 0x67676d6c) {
+            fprintf(stderr, "%s: invalid model file '%s' (bad magic)\n", __func__, params.model.c_str());
+            return false;
+        }
+    }
+
+    // load hparams
+    {
+        // Override defaults with user choices
+        model.hparams.mask_threshold            = params.mask_threshold;
+        model.hparams.iou_threshold             = params.iou_threshold;
+        model.hparams.stability_score_threshold = params.stability_score_threshold;
+        model.hparams.stability_score_offset    = params.stability_score_offset;
+        model.hparams.eps                       = params.eps;
+        model.hparams.eps_decoder_transformer   = params.eps_decoder_transformer;
+
+        auto & hparams = model.hparams;
+
+        fin.read((char *) &hparams.n_enc_state,     sizeof(hparams.n_enc_state));
+        fin.read((char *) &hparams.n_enc_layer,     sizeof(hparams.n_enc_layer));
+        fin.read((char *) &hparams.n_enc_head,      sizeof(hparams.n_enc_head));
+        fin.read((char *) &hparams.n_enc_out_chans, sizeof(hparams.n_enc_out_chans));
+        fin.read((char *) &hparams.n_pt_embd,       sizeof(hparams.n_pt_embd));
+        fin.read((char *) &hparams.ftype,           sizeof(hparams.ftype));
+
+        const int32_t qntvr = hparams.ftype / GGML_QNT_VERSION_FACTOR;
+
+        printf("%s: n_enc_state      = %d\n", __func__, hparams.n_enc_state);
+        printf("%s: n_enc_layer      = %d\n", __func__, hparams.n_enc_layer);
+        printf("%s: n_enc_head       = %d\n", __func__, hparams.n_enc_head);
+        printf("%s: n_enc_out_chans  = %d\n", __func__, hparams.n_enc_out_chans);
+        printf("%s: n_pt_embd        = %d\n", __func__, hparams.n_pt_embd);
+        printf("%s: ftype            = %d\n", __func__, hparams.ftype);
+        printf("%s: qntvr            = %d\n", __func__, qntvr);
+
+        hparams.ftype %= GGML_QNT_VERSION_FACTOR;
+
+    }
+
+    // for the big tensors, we have the option to store the data in 16-bit floats or quantized
+    // in order to save memory and also to speed up the computation
+    ggml_type wtype = ggml_ftype_to_ggml_type((ggml_ftype) (model.hparams.ftype));
+    if (wtype == GGML_TYPE_COUNT) {
+        fprintf(stderr, "%s: invalid model file '%s' (bad ftype value %d)\n",
+                __func__, params.model.c_str(), model.hparams.ftype);
+        return false;
+    }
+
+    auto & ctx = model.ctx;
+
+    const size_t ctx_size = [&]() {
+        size_t ctx_size = 0;
+
+        const auto & hparams = model.hparams;
+
+        const int32_t n_enc_state     = hparams.n_enc_state;
+        const int32_t n_enc_layer     = hparams.n_enc_layer;
+        const int32_t n_enc_head_dim  = hparams.n_enc_head_dim();
+        const int32_t n_enc_out_chans = hparams.n_enc_out_chans;
+        const int32_t n_pt_embd       = hparams.n_pt_embd;
+
+        const int32_t n_enc_layer_local  = hparams.global_attn_indices().size();
+        const int32_t n_enc_layer_global = n_enc_layer - n_enc_layer_local;
+
+        const int32_t n_img_embd    = hparams.n_img_embd();
+        const int32_t n_window_size = hparams.n_window_size();
+        const int32_t n_patch_size  = hparams.n_patch_size();
+
+        // image encoder
+        {
+            ctx_size += n_enc_state*n_img_embd*n_img_embd*ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size += n_enc_state*3*n_patch_size*n_patch_size*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_state*ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size +=     n_enc_state*n_enc_out_chans*1*1*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_out_chans*n_enc_out_chans*3*3*ggml_type_size(GGML_TYPE_F16);
+
+            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+        }
+
+        // image encoder layers
+        {
+            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size += n_enc_layer_global*n_enc_head_dim*(2*n_img_embd - 1)*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_layer_global*n_enc_head_dim*(2*n_img_embd - 1)*ggml_type_size(GGML_TYPE_F16);
+
+            ctx_size += n_enc_layer_local*n_enc_head_dim*(2*n_window_size - 1)*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_layer_local*n_enc_head_dim*(2*n_window_size - 1)*ggml_type_size(GGML_TYPE_F16);
+
+            ctx_size += n_enc_layer*3*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_layer*3*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size += n_enc_layer*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_layer*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+            ctx_size += n_enc_layer*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size += n_enc_layer*4*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_layer*4*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
+
+            ctx_size += n_enc_layer*4*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
+            ctx_size += n_enc_layer*4*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
+        }
+
+        ctx_size += (8 + 14*n_enc_layer)*ggml_tensor_overhead();
+
+        // prompt encoder
+        {
+            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F16); // 2*(n_enc_out_chans/2)
+
+            ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+            ctx_size += n_pt_embd*n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+        }
+
+        ctx_size += (2 + n_pt_embd)*ggml_tensor_overhead();
+
+        // mask decoder
+        {
+            //transformer
+            {
+                const int tfm_layers_count = 2;
+                const int qkv_count = 3;
+                const int norm_count = 4;
+                const int n_hypernet_mpls_count = 4;
+
+                // self_attn
+                ctx_size += tfm_layers_count*qkv_count*n_enc_state*n_enc_state*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += tfm_layers_count*qkv_count*n_enc_state*            ggml_type_size(GGML_TYPE_F32);
+                ctx_size += tfm_layers_count*n_enc_state*                      ggml_type_size(GGML_TYPE_F32);
+
+                // all norms
+                ctx_size += tfm_layers_count*norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+                ctx_size += tfm_layers_count*norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+
+                // cross_attn_token_to_img
+                ctx_size += tfm_layers_count*qkv_count*n_enc_state*(n_enc_state/2)*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += tfm_layers_count*qkv_count*(n_enc_state/2)*            ggml_type_size(GGML_TYPE_F32);
+                ctx_size += tfm_layers_count*n_enc_state*                          ggml_type_size(GGML_TYPE_F32);
+
+                // mlp
+                ctx_size += tfm_layers_count*8*n_enc_out_chans*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += tfm_layers_count*8*n_enc_out_chans*                ggml_type_size(GGML_TYPE_F32);
+                ctx_size += tfm_layers_count*n_enc_out_chans*8*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += tfm_layers_count*n_enc_out_chans*                  ggml_type_size(GGML_TYPE_F32);
+
+                // cross_attn_img_to_token
+                ctx_size += tfm_layers_count*qkv_count*n_enc_state*(n_enc_state/2)*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += tfm_layers_count*qkv_count*(n_enc_state/2)*            ggml_type_size(GGML_TYPE_F32);
+                ctx_size += tfm_layers_count*n_enc_state*                          ggml_type_size(GGML_TYPE_F32);
+
+                // transformer_final_attn_token_to_img
+                ctx_size += qkv_count*n_enc_state*(n_enc_state/2)*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += qkv_count*(n_enc_state/2)*            ggml_type_size(GGML_TYPE_F32);
+                ctx_size += n_enc_state*                          ggml_type_size(GGML_TYPE_F32);
+
+                // transformer_norm_final
+                ctx_size += norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+                ctx_size += norm_count*n_enc_state*ggml_type_size(GGML_TYPE_F32);
+
+                // output_upscaling
+                ctx_size += n_enc_out_chans*n_img_embd*2*2*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += 3*n_img_embd*                  ggml_type_size(GGML_TYPE_F32);
+                ctx_size += n_enc_out_chans*n_img_embd*(n_img_embd/2)*2*2*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += (n_img_embd/2)*                               ggml_type_size(GGML_TYPE_F32);
+
+                // output_hypernetworks_mlps
+                ctx_size += n_hypernet_mpls_count*2*n_enc_out_chans*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += n_hypernet_mpls_count*2*n_enc_out_chans*                ggml_type_size(GGML_TYPE_F32);
+                ctx_size += n_hypernet_mpls_count*n_enc_out_chans*(n_img_embd/2)*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += n_hypernet_mpls_count*(n_img_embd/2)*                ggml_type_size(GGML_TYPE_F32);
+
+                // iou_prediction_head
+                ctx_size += 2*n_enc_out_chans*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += 2*n_enc_out_chans*                ggml_type_size(GGML_TYPE_F32);
+                ctx_size += n_pt_embd*n_enc_out_chans*ggml_type_size(GGML_TYPE_F16);
+                ctx_size += n_pt_embd*                ggml_type_size(GGML_TYPE_F32);
+
+                // iou_token_w
+                ctx_size += n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+
+                // mask_tokens_w
+                ctx_size += n_pt_embd*n_enc_out_chans*ggml_type_size(GGML_TYPE_F32);
+            }
+        }
+        fprintf(stderr, "%s: ggml ctx size = %6.2f MB\n", __func__, ctx_size/(1024.0*1024.0));
+
+        return ctx_size;
+    }();
+
+    // create the ggml context
+    {
+        struct ggml_init_params params = {
+            /*.mem_size   =*/ ctx_size,
+            /*.mem_buffer =*/ NULL,
+            /*.no_alloc   =*/ false,
+        };
+
+        ctx = ggml_init(params);
+        if (!ctx) {
+            fprintf(stderr, "%s: ggml_init() failed\n", __func__);
+            return false;
+        }
+    }
+
+    // prepare memory for the weights
+    {
+        const auto & hparams = model.hparams;
+
+        const int32_t n_enc_state      = hparams.n_enc_state;
+        const int32_t n_enc_layer      = hparams.n_enc_layer;
+        const int32_t n_enc_head_dim   = hparams.n_enc_head_dim();
+        const int32_t n_enc_out_chans  = hparams.n_enc_out_chans;
+        const int32_t n_pt_embd        = hparams.n_pt_embd;
+
+        const int32_t n_img_embd    = hparams.n_img_embd();
+        const int32_t n_window_size = hparams.n_window_size();
+        const int32_t n_patch_size  = hparams.n_patch_size();
+
+        model.enc_img.layers.resize(n_enc_layer);
+
+        // image encoder
+        {
+            auto & enc = model.enc_img;
+
+            enc.pe = ggml_new_tensor_4d(ctx, GGML_TYPE_F32, n_enc_state, n_img_embd, n_img_embd, 1);
+
+            enc.proj_w = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, n_patch_size, n_patch_size,           3, n_enc_state);
+            enc.proj_b = ggml_new_tensor_3d(ctx, GGML_TYPE_F32,            1,            1, n_enc_state);
+
+            enc.neck_conv_0 = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, 1, 1, n_enc_state,     n_enc_out_chans);
+            enc.neck_conv_1 = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, 3, 3, n_enc_out_chans, n_enc_out_chans);
+
+            enc.neck_norm_0_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+            enc.neck_norm_0_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+            enc.neck_norm_1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+            enc.neck_norm_1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+            model.tensors["image_encoder.pos_embed"] = enc.pe;
+
+            model.tensors["image_encoder.patch_embed.proj.weight"] = enc.proj_w;
+            model.tensors["image_encoder.patch_embed.proj.bias"]   = enc.proj_b;
+
+            model.tensors["image_encoder.neck.0.weight"] = enc.neck_conv_0;
+            model.tensors["image_encoder.neck.2.weight"] = enc.neck_conv_1;
+
+            model.tensors["image_encoder.neck.1.weight"] = enc.neck_norm_0_w;
+            model.tensors["image_encoder.neck.1.bias"]   = enc.neck_norm_0_b;
+
+            model.tensors["image_encoder.neck.3.weight"] = enc.neck_norm_1_w;
+            model.tensors["image_encoder.neck.3.bias"]   = enc.neck_norm_1_b;
+
+            for (int i = 0; i < n_enc_layer; ++i) {
+                auto & layer = enc.layers[i];
+
+                layer.norm1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
+                layer.norm1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
+
+                if (hparams.is_global_attn(i)) {
+                    layer.rel_pos_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_img_embd - 1);
+                    layer.rel_pos_h = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_img_embd - 1);
+                } else {
+                    layer.rel_pos_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_window_size - 1);
+                    layer.rel_pos_h = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_head_dim, 2*n_window_size - 1);
+                }
+
+                layer.qkv_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16,   n_enc_state, 3*n_enc_state);
+                layer.qkv_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 3*n_enc_state);
+
+                layer.proj_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16,  n_enc_state,   n_enc_state);
+                layer.proj_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32,  n_enc_state);
+
+                layer.norm2_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
+                layer.norm2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_state);
+
+                layer.mlp_lin1_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16,   n_enc_state, 4*n_enc_state);
+                layer.mlp_lin1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 4*n_enc_state);
+
+                layer.mlp_lin2_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, 4*n_enc_state,   n_enc_state);
+                layer.mlp_lin2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32,   n_enc_state);
+
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm1.weight"] = layer.norm1_w;
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm1.bias"]   = layer.norm1_b;
+
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.rel_pos_w"] = layer.rel_pos_w;
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.rel_pos_h"] = layer.rel_pos_h;
+
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.qkv.weight"] = layer.qkv_w;
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.qkv.bias"]   = layer.qkv_b;
+
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.proj.weight"] = layer.proj_w;
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".attn.proj.bias"]   = layer.proj_b;
+
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm2.weight"] = layer.norm2_w;
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".norm2.bias"]   = layer.norm2_b;
+
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin1.weight"] = layer.mlp_lin1_w;
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin1.bias"]   = layer.mlp_lin1_b;
+
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin2.weight"] = layer.mlp_lin2_w;
+                model.tensors["image_encoder.blocks." + std::to_string(i) + ".mlp.lin2.bias"]   = layer.mlp_lin2_b;
+            }
+        }
+
+        // prompt encoder
+        {
+            auto & enc = model.enc_prompt;
+
+            enc.pe = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, n_enc_out_chans/2, 2);
+
+            enc.not_a_pt_embd_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+            enc.no_mask_embd_w  = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+            model.tensors["prompt_encoder.pe_layer.positional_encoding_gaussian_matrix"] = enc.pe;
+            model.tensors["prompt_encoder.not_a_point_embed.weight"] = enc.not_a_pt_embd_w;
+            model.tensors["prompt_encoder.no_mask_embed.weight"]     = enc.no_mask_embd_w;
+
+            enc.pt_embd.resize(n_pt_embd);
+            for (int i = 0; i < n_pt_embd; i++) {
+                enc.pt_embd[i] = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                model.tensors["prompt_encoder.point_embeddings." + std::to_string(i) + ".weight"] = enc.pt_embd[i];
+            }
+        }
+
+        // mask decoder
+        {
+            auto & dec = model.dec;
+            auto & tfm_layers = dec.transformer_layers;
+
+            const int tfm_layers_count = 2;
+            tfm_layers.resize(tfm_layers_count);
+            for (int i = 0; i < tfm_layers_count; ++i) {
+                auto& l = tfm_layers[i];
+                l.self_attn.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+                l.self_attn.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                l.self_attn.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+                l.self_attn.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                l.self_attn.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+                l.self_attn.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                l.self_attn.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+                l.self_attn.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                l.norm1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                l.norm1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                l.cross_attn_token_to_img.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+                l.cross_attn_token_to_img.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+                l.cross_attn_token_to_img.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+                l.cross_attn_token_to_img.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+                l.cross_attn_token_to_img.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+                l.cross_attn_token_to_img.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+                l.cross_attn_token_to_img.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans/2, n_enc_out_chans);
+                l.cross_attn_token_to_img.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                l.norm2_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                l.norm2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                l.mlp_lin1_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, 8*n_enc_out_chans);
+                l.mlp_lin1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 8*n_enc_out_chans);
+                l.mlp_lin2_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, 8*n_enc_out_chans, n_enc_out_chans);
+                l.mlp_lin2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                l.norm3_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                l.norm3_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                l.norm4_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                l.norm4_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                l.cross_attn_img_to_token.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+                l.cross_attn_img_to_token.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+                l.cross_attn_img_to_token.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+                l.cross_attn_img_to_token.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+                l.cross_attn_img_to_token.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+                l.cross_attn_img_to_token.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+                l.cross_attn_img_to_token.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans/2, n_enc_out_chans);
+                l.cross_attn_img_to_token.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+                const auto prefix = "mask_decoder.transformer.layers." + std::to_string(i) + ".";
+                model.tensors[prefix + "self_attn.q_proj.weight"] = l.self_attn.q_w;
+                model.tensors[prefix + "self_attn.q_proj.bias"]   = l.self_attn.q_b;
+                model.tensors[prefix + "self_attn.k_proj.weight"] = l.self_attn.k_w;
+                model.tensors[prefix + "self_attn.k_proj.bias"]   = l.self_attn.k_b;
+                model.tensors[prefix + "self_attn.v_proj.weight"] = l.self_attn.v_w;
+                model.tensors[prefix + "self_attn.v_proj.bias"]   = l.self_attn.v_b;
+                model.tensors[prefix + "self_attn.out_proj.weight"] = l.self_attn.out_w;
+                model.tensors[prefix + "self_attn.out_proj.bias"]   = l.self_attn.out_b;
+
+                model.tensors[prefix + "norm1.weight"] = l.norm1_w;
+                model.tensors[prefix + "norm1.bias"]   = l.norm1_b;
+
+                model.tensors[prefix + "cross_attn_token_to_image.q_proj.weight"] = l.cross_attn_token_to_img.q_w;
+                model.tensors[prefix + "cross_attn_token_to_image.q_proj.bias"]   = l.cross_attn_token_to_img.q_b;
+                model.tensors[prefix + "cross_attn_token_to_image.k_proj.weight"] = l.cross_attn_token_to_img.k_w;
+                model.tensors[prefix + "cross_attn_token_to_image.k_proj.bias"]   = l.cross_attn_token_to_img.k_b;
+                model.tensors[prefix + "cross_attn_token_to_image.v_proj.weight"] = l.cross_attn_token_to_img.v_w;
+                model.tensors[prefix + "cross_attn_token_to_image.v_proj.bias"]   = l.cross_attn_token_to_img.v_b;
+                model.tensors[prefix + "cross_attn_token_to_image.out_proj.weight"] = l.cross_attn_token_to_img.out_w;
+                model.tensors[prefix + "cross_attn_token_to_image.out_proj.bias"]   = l.cross_attn_token_to_img.out_b;
+
+                model.tensors[prefix + "norm2.weight"] = l.norm2_w;
+                model.tensors[prefix + "norm2.bias"]   = l.norm2_b;
+
+                model.tensors[prefix + "mlp.lin1.weight"] = l.mlp_lin1_w;
+                model.tensors[prefix + "mlp.lin1.bias"]   = l.mlp_lin1_b;
+                model.tensors[prefix + "mlp.lin2.weight"] = l.mlp_lin2_w;
+                model.tensors[prefix + "mlp.lin2.bias"]   = l.mlp_lin2_b;
+
+                model.tensors[prefix + "norm3.weight"] = l.norm3_w;
+                model.tensors[prefix + "norm3.bias"]   = l.norm3_b;
+                model.tensors[prefix + "norm4.weight"] = l.norm4_w;
+                model.tensors[prefix + "norm4.bias"]   = l.norm4_b;
+
+                model.tensors[prefix + "cross_attn_image_to_token.q_proj.weight"] = l.cross_attn_img_to_token.q_w;
+                model.tensors[prefix + "cross_attn_image_to_token.q_proj.bias"]   = l.cross_attn_img_to_token.q_b;
+                model.tensors[prefix + "cross_attn_image_to_token.k_proj.weight"] = l.cross_attn_img_to_token.k_w;
+                model.tensors[prefix + "cross_attn_image_to_token.k_proj.bias"]   = l.cross_attn_img_to_token.k_b;
+                model.tensors[prefix + "cross_attn_image_to_token.v_proj.weight"] = l.cross_attn_img_to_token.v_w;
+                model.tensors[prefix + "cross_attn_image_to_token.v_proj.bias"]   = l.cross_attn_img_to_token.v_b;
+                model.tensors[prefix + "cross_attn_image_to_token.out_proj.weight"] = l.cross_attn_img_to_token.out_w;
+                model.tensors[prefix + "cross_attn_image_to_token.out_proj.bias"]   = l.cross_attn_img_to_token.out_b;
+            }
+
+            dec.transformer_final_attn_token_to_img.q_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+            dec.transformer_final_attn_token_to_img.q_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+            dec.transformer_final_attn_token_to_img.k_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+            dec.transformer_final_attn_token_to_img.k_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+            dec.transformer_final_attn_token_to_img.v_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans/2);
+            dec.transformer_final_attn_token_to_img.v_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans/2);
+            dec.transformer_final_attn_token_to_img.out_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans/2, n_enc_out_chans);
+            dec.transformer_final_attn_token_to_img.out_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.q_proj.weight"] = dec.transformer_final_attn_token_to_img.q_w;
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.q_proj.bias"]   = dec.transformer_final_attn_token_to_img.q_b;
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.k_proj.weight"] = dec.transformer_final_attn_token_to_img.k_w;
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.k_proj.bias"]   = dec.transformer_final_attn_token_to_img.k_b;
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.v_proj.weight"] = dec.transformer_final_attn_token_to_img.v_w;
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.v_proj.bias"]   = dec.transformer_final_attn_token_to_img.v_b;
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.out_proj.weight"] = dec.transformer_final_attn_token_to_img.out_w;
+            model.tensors["mask_decoder.transformer.final_attn_token_to_image.out_proj.bias"]   = dec.transformer_final_attn_token_to_img.out_b;
+
+            dec.transformer_norm_final_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+            dec.transformer_norm_final_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+
+            model.tensors["mask_decoder.transformer.norm_final_attn.weight"] = dec.transformer_norm_final_w;
+            model.tensors["mask_decoder.transformer.norm_final_attn.bias"]   = dec.transformer_norm_final_b;
+
+            dec.output_upscaling_0_w = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, 2, 2, n_img_embd, n_enc_out_chans);
+            dec.output_upscaling_0_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd);
+            dec.output_upscaling_1_w = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd);
+            dec.output_upscaling_1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd);
+            dec.output_upscaling_3_w = ggml_new_tensor_4d(ctx, GGML_TYPE_F16,  2, 2, n_img_embd/2, n_img_embd);
+            dec.output_upscaling_3_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd/2);
+
+            model.tensors["mask_decoder.output_upscaling.0.weight"] = dec.output_upscaling_0_w;
+            model.tensors["mask_decoder.output_upscaling.0.bias"]   = dec.output_upscaling_0_b;
+            model.tensors["mask_decoder.output_upscaling.1.weight"] = dec.output_upscaling_1_w;
+            model.tensors["mask_decoder.output_upscaling.1.bias"]   = dec.output_upscaling_1_b;
+            model.tensors["mask_decoder.output_upscaling.3.weight"] = dec.output_upscaling_3_w;
+            model.tensors["mask_decoder.output_upscaling.3.bias"]   = dec.output_upscaling_3_b;
+
+            const int n_hypernet_mpls_count = 4;
+            dec.output_hypernet_mlps.resize(n_hypernet_mpls_count);
+            for (int i = 0; i < n_hypernet_mpls_count; ++i) {
+                auto& mlp = dec.output_hypernet_mlps[i];
+
+                mlp.w_0 = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+                mlp.b_0 = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                mlp.w_1 = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+                mlp.b_1 = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+                mlp.w_2 = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_img_embd/2);
+                mlp.b_2 = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_img_embd/2);
+
+                const auto prefix = "mask_decoder.output_hypernetworks_mlps." + std::to_string(i) + ".";
+                model.tensors[prefix + "layers.0.weight"] = mlp.w_0;
+                model.tensors[prefix + "layers.0.bias"]   = mlp.b_0;
+                model.tensors[prefix + "layers.1.weight"] = mlp.w_1;
+                model.tensors[prefix + "layers.1.bias"]   = mlp.b_1;
+                model.tensors[prefix + "layers.2.weight"] = mlp.w_2;
+                model.tensors[prefix + "layers.2.bias"]   = mlp.b_2;
+            }
+
+            dec.iou_prediction_head_0_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+            dec.iou_prediction_head_0_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+            dec.iou_prediction_head_1_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_enc_out_chans);
+            dec.iou_prediction_head_1_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_enc_out_chans);
+            dec.iou_prediction_head_2_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F16, n_enc_out_chans, n_pt_embd);
+            dec.iou_prediction_head_2_b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, n_pt_embd);
+
+            dec.iou_token_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, n_enc_out_chans, 1);
+            dec.mask_tokens_w = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, n_enc_out_chans, n_pt_embd);
+
+            model.tensors["mask_decoder.iou_prediction_head.layers.0.weight"] = dec.iou_prediction_head_0_w;
+            model.tensors["mask_decoder.iou_prediction_head.layers.0.bias"]   = dec.iou_prediction_head_0_b;
+            model.tensors["mask_decoder.iou_prediction_head.layers.1.weight"] = dec.iou_prediction_head_1_w;
+            model.tensors["mask_decoder.iou_prediction_head.layers.1.bias"]   = dec.iou_prediction_head_1_b;
+            model.tensors["mask_decoder.iou_prediction_head.layers.2.weight"] = dec.iou_prediction_head_2_w;
+            model.tensors["mask_decoder.iou_prediction_head.layers.2.bias"]   = dec.iou_prediction_head_2_b;
+
+            model.tensors["mask_decoder.iou_token.weight"] = dec.iou_token_w;
+            model.tensors["mask_decoder.mask_tokens.weight"] = dec.mask_tokens_w;
+        }
+    }
+
+    // load weights
+    {
+        int n_tensors = 0;
+        size_t total_size = 0;
+
+        fprintf(stderr, "%s: ", __func__);
+
+        while (true) {
+            int32_t n_dims;
+            int32_t length;
+            int32_t ftype;
+
+            fin.read(reinterpret_cast<char *>(&n_dims), sizeof(n_dims));
+            fin.read(reinterpret_cast<char *>(&length), sizeof(length));
+            fin.read(reinterpret_cast<char *>(&ftype),  sizeof(ftype));
+
+            if (fin.eof()) {
+                break;
+            }
+
+            int64_t nelements = 1;
+            int64_t ne[4] = { 1, 1, 1, 1 };
+            for (int i = 0; i < n_dims; ++i) {
+                int32_t ne_cur;
+                fin.read(reinterpret_cast<char *>(&ne_cur), sizeof(ne_cur));
+                ne[i] = ne_cur;
+                nelements *= ne[i];
+            }
+
+            std::string name(length, 0);
+            fin.read(&name[0], length);
+
+            if (model.tensors.find(name.data()) == model.tensors.end()) {
+                fprintf(stderr, "%s: unknown tensor '%s' in model file\n", __func__, name.data());
+                return false;
+            }
+
+            auto tensor = model.tensors[name.data()];
+            //printf("ne0 = %jd, ne1 = %jd, ne2 = %jd, ne3 = %jd\n", ne[0], ne[1], ne[2], ne[3]);
+
+            if (ggml_nelements(tensor) != nelements) {
+                fprintf(stderr, "%s: tensor '%s' has wrong size in model file: got %d, expected %d\n",
+                        __func__, name.data(), (int) nelements, (int) ggml_nelements(tensor));
+                return false;
+            }
+
+            if (tensor->ne[0] != ne[0] || tensor->ne[1] != ne[1] || tensor->ne[2] != ne[2] || tensor->ne[3] != ne[3]) {
+                fprintf(stderr, "%s: tensor '%s' has wrong shape in model file: got [%d, %d, %d, %d], expected [%d, %d, %d, %d]\n",
+                        __func__, name.data(),
+                        (int) ne[0], (int) ne[1], (int) ne[2], (int) ne[3],
+                        (int) tensor->ne[0], (int) tensor->ne[1], (int) tensor->ne[2], (int) tensor->ne[3]);
+                return false;
+            }
+
+            size_t bpe = 0;
+
+            switch (ftype) {
+                case 0: bpe = ggml_type_size(GGML_TYPE_F32);  break;
+                case 1: bpe = ggml_type_size(GGML_TYPE_F16);  break;
+                case 2: bpe = ggml_type_size(GGML_TYPE_Q4_0); assert(ne[0] % 64 == 0); break;
+                case 3: bpe = ggml_type_size(GGML_TYPE_Q4_1); assert(ne[0] % 64 == 0); break;
+                default:
+                        {
+                            fprintf(stderr, "%s: unknown ftype %d in model file\n", __func__, ftype);
+                            return false;
+                        }
+            };
+
+            if ((nelements*bpe)/ggml_blck_size(tensor->type) != ggml_nbytes(tensor)) {
+                fprintf(stderr, "%s: tensor '%s' has wrong size in model file: got %zu, expected %zu\n",
+                        __func__, name.data(), ggml_nbytes(tensor), (size_t) nelements*bpe);
+                return false;
+            }
+
+            fin.read(reinterpret_cast<char *>(tensor->data), ggml_nbytes(tensor));
+
+            total_size += ggml_nbytes(tensor);
+            if (++n_tensors % 8 == 0) {
+                fprintf(stderr, ".");
+                fflush(stdout);
+            }
+        }
+
+        if (n_tensors != int(model.tensors.size())) {
+            fprintf(stderr, "%s: model file has %d tensors, but %d tensors were expected\n", __func__, n_tensors, (int) model.tensors.size());
+            return false;
+        }
+
+        fprintf(stderr, " done\n");
+
+        fprintf(stderr, "%s: model size = %8.2f MB / num tensors = %d\n", __func__, total_size/1024.0/1024.0, n_tensors);
+    }
+
+    fin.close();
+
+    return true;
+}
+
+struct ggml_tensor * sam_fill_dense_pe(
+            const sam_model   & model,
+          struct ggml_context * ctx0,
+          struct ggml_cgraph  * gf,
+                  sam_state   & state) {
+    const auto & hparams = model.hparams;
+    const auto & enc     = model.enc_prompt;
+
+
+    const int32_t n_img_embd = hparams.n_img_embd();
+    struct ggml_tensor * xy_embed_stacked = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, 2, n_img_embd, n_img_embd);
+    ggml_set_name(xy_embed_stacked, "xy_embed_stacked");
+    ggml_set_input(xy_embed_stacked);
+
+    struct ggml_tensor * cur = ggml_mul_mat(ctx0, ggml_cont(ctx0, ggml_transpose(ctx0, enc.pe)), xy_embed_stacked);
+
+    cur = ggml_scale(ctx0, cur, float(2.0*M_PI));
+
+    // concat
+    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L192
+    {
+        struct ggml_tensor * t_sin = ggml_map_custom1(ctx0, cur, ggml_sam_sin, GGML_N_TASKS_MAX, NULL);
+        struct ggml_tensor * t_cos = ggml_map_custom1(ctx0, cur, ggml_sam_cos, GGML_N_TASKS_MAX, NULL);
+
+        cur = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, t_sin->ne[0] + t_cos->ne[0], cur->ne[1], cur->ne[2]);
+
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_sin, ggml_view_3d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], t_sin->ne[2], cur->nb[1], cur->nb[2], 0)));
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_cos, ggml_view_3d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], t_sin->ne[2], cur->nb[1], cur->nb[2], t_sin->nb[1])));
+    }
+
+    struct ggml_tensor * pe_img_dense = ggml_cont(ctx0, ggml_permute(ctx0, cur, 2, 0, 1, 3));
+    ggml_build_forward_expand(gf, pe_img_dense);
+
+    return pe_img_dense;
+}
+
+struct ggml_tensor* sam_layer_norm_2d(
+                    struct ggml_context * ctx0,
+                    struct ggml_tensor  * layer,
+                    int                   n_channels,
+                    struct ggml_tensor  * w,
+                    struct ggml_tensor  * b,
+                    float                 eps) {
+    // LayerNorm2d
+    // normalize along channel dimmension
+    // TODO: better implementation
+    layer = ggml_permute(ctx0,
+                ggml_norm(ctx0, ggml_cont(ctx0, ggml_permute(ctx0, layer, 1, 2, 0, 3)), eps),
+                2, 0, 1, 3);
+
+    layer = ggml_add(ctx0,
+              ggml_mul(ctx0,
+                  ggml_repeat(ctx0, ggml_reshape_3d(ctx0, w, 1, 1, n_channels), layer),
+                  layer),
+              ggml_repeat(ctx0, ggml_reshape_3d(ctx0, b, 1, 1, n_channels), layer));
+
+    return layer;
+}
+
+struct ggml_cgraph  * sam_encode_image(
+            const sam_model & model,
+                  sam_state & state,
+        const sam_image_f32 & img) {
+
+    const auto & hparams = model.hparams;
+    const auto & enc     = model.enc_img;
+
+    const int32_t n_enc_state     = hparams.n_enc_state;
+    const int32_t n_enc_layer     = hparams.n_enc_layer;
+    const int32_t n_enc_head      = hparams.n_enc_head;
+    const int32_t n_enc_head_dim  = hparams.n_enc_head_dim();
+    const int32_t n_enc_out_chans = hparams.n_enc_out_chans;
+    const int32_t n_img_size    = hparams.n_img_size();
+    const int32_t n_window_size = hparams.n_window_size();
+
+    struct ggml_init_params ggml_params = {
+        /*.mem_size   =*/ state.buf_compute_img_enc.size(),
+        /*.mem_buffer =*/ state.buf_compute_img_enc.data(),
+        /*.no_alloc   =*/ true, // skip allocating as we use ggml_alloc to allocate exact memory requirements
+    };
+
+    struct ggml_context * ctx0   = ggml_init(ggml_params);
+    struct ggml_cgraph  * gf     = ggml_new_graph(ctx0);
+
+    struct ggml_tensor * inp = ggml_new_tensor_4d(ctx0, GGML_TYPE_F32, n_img_size, n_img_size, 3, 1);
+    ggml_set_name(inp, "inp");
+    ggml_set_input(inp);
+
+    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L392
+    struct ggml_tensor * cur = ggml_conv_2d_sk_p0(ctx0, enc.proj_w, inp);
+    cur = ggml_add_inplace(ctx0,
+            cur,
+            ggml_repeat(ctx0, enc.proj_b, cur));
+
+    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L394
+    // keep in F32
+    cur = ggml_cont(ctx0,
+            ggml_permute(ctx0, cur, 1, 2, 0, 3));
+
+    // convert to F16
+    //cur = ggml_cpy(ctx0,
+    //        ggml_permute(ctx0, cur, 1, 2, 0, 3),
+    //        ggml_new_tensor_3d(ctx0, GGML_TYPE_F16, n_enc_state, n_img_embd, n_img_embd));
+
+    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L108-L109
+    cur = ggml_add_inplace(ctx0, cur, enc.pe);
+
+    struct ggml_tensor * inpL = cur;
+
+    for (int il = 0; il < n_enc_layer; ++il) {
+        const auto & layer = enc.layers[il];
+
+        // norm
+        // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L168
+        {
+            cur = ggml_norm(ctx0, inpL, hparams.eps);
+
+            // cur = ln_0_w*cur + ln_0_b
+            cur = ggml_mul(ctx0, cur, layer.norm1_w);
+            cur = ggml_add_inplace(ctx0, cur, layer.norm1_b);
+        }
+
+        const int64_t w0 = cur->ne[1];
+        const int64_t h0 = cur->ne[2];
+
+        if (hparams.is_global_attn(il) == false) {
+            // local attention layer - apply window partition
+            // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L169-L172
+            cur = ggml_win_part(ctx0, cur, n_window_size);
+        }
+
+        const int64_t W = cur->ne[1];
+        const int64_t H = cur->ne[2];
+
+        // self-attention
+        {
+            cur = ggml_mul_mat(ctx0, layer.qkv_w, cur);
+            cur = ggml_add_inplace(ctx0, cur, layer.qkv_b);
+
+            // split qkv into separate tensors
+            // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/image_encoder.py#L225-L229
+            const int B = cur->ne[3];
+
+            cur = ggml_reshape_4d(ctx0, cur, n_enc_state, 3, W*H, B);
+            cur = ggml_cont(ctx0, ggml_permute(ctx0, cur, 0, 3, 1, 2));
+
+            struct ggml_tensor * Q;
+            struct ggml_tensor * K;
+            struct ggml_tensor * V;
+
+            Q = ggml_view_3d   (ctx0, cur, n_enc_state, W*H, B, cur->nb[1], cur->nb[2], 0*cur->nb[3]);
+            Q = ggml_reshape_4d(ctx0, Q,   n_enc_head_dim, n_enc_head, W*H, B);
+            Q = ggml_cont      (ctx0, ggml_permute(ctx0, Q, 0, 2, 1, 3));
+            Q = ggml_reshape_3d(ctx0, Q,   n_enc_head_dim, W*H, B*n_enc_head);
+
+            K = ggml_view_3d   (ctx0, cur, n_enc_state, W*H, B, cur->nb[1], cur->nb[2], 1*cur->nb[3]);
+            K = ggml_reshape_4d(ctx0, K,   n_enc_head_dim, n_enc_head, W*H, B);
+            K = ggml_cont      (ctx0, ggml_permute(ctx0, K, 0, 2, 1, 3));
+            K = ggml_reshape_3d(ctx0, K,   n_enc_head_dim, W*H, B*n_enc_head);
+
+            V = ggml_view_3d   (ctx0, cur, n_enc_state, W*H, B, cur->nb[1], cur->nb[2], 2*cur->nb[3]);
+            V = ggml_reshape_4d(ctx0, V,   n_enc_head_dim, n_enc_head, W*H, B);
+            V = ggml_cont      (ctx0, ggml_permute(ctx0, V, 1, 2, 0, 3)); // transposed
+            V = ggml_reshape_3d(ctx0, V,   W*H, n_enc_head_dim, B*n_enc_head);
+
+            struct ggml_tensor * KQ = ggml_mul_mat(ctx0, K, Q);
+
+            struct ggml_tensor * KQ_scaled =
+                ggml_scale_inplace(ctx0,
+                        KQ,
+                        1.0f/sqrtf(n_enc_head_dim));
+
+            struct ggml_tensor * rw = ggml_get_rel_pos(ctx0, layer.rel_pos_w, W, W);
+            struct ggml_tensor * rh = ggml_get_rel_pos(ctx0, layer.rel_pos_h, H, H);
+
+            struct ggml_tensor * q_r = ggml_reshape_4d(ctx0, Q, n_enc_head_dim, W, H, B*n_enc_head);
+
+            struct ggml_tensor * rel_w = ggml_cont(ctx0, ggml_permute(ctx0,
+                        ggml_mul_mat(ctx0,
+                            rw,
+                            ggml_cont(ctx0, ggml_permute(ctx0, q_r, 0, 2, 1, 3))),
+                        0, 2, 1, 3));
+            struct ggml_tensor * rel_h = ggml_mul_mat(ctx0, rh, q_r);
+
+            struct ggml_tensor * attn = ggml_add_rel_pos_inplace(ctx0, KQ_scaled, rel_w, rel_h);
+
+            struct ggml_tensor * KQ_soft_max = ggml_soft_max_inplace(ctx0, attn);
+
+            struct ggml_tensor * KQV = ggml_mul_mat(ctx0, V, KQ_soft_max);
+
+            cur =
+                ggml_reshape_4d(ctx0,
+                        ggml_cont(ctx0,
+                            ggml_permute(ctx0,
+                                ggml_reshape_4d(ctx0, KQV, n_enc_head_dim, W*H, n_enc_head, B),
+                                0, 2, 1, 3)),
+                        n_enc_state, W, H, B);
+
+            cur = ggml_mul_mat(ctx0, layer.proj_w, cur);
+            cur = ggml_add_inplace(ctx0, cur, layer.proj_b);
+        }
+
+        if (hparams.is_global_attn(il) == false) {
+            // local attention layer - reverse window partition
+            cur = ggml_win_unpart(ctx0, cur, w0, h0, n_window_size);
+        }
+
+        cur = ggml_add_inplace(ctx0, cur, inpL);
+
+        struct ggml_tensor * inpFF = cur;
+
+        // feed-forward network
+        {
+            // norm
+            {
+                cur = ggml_norm(ctx0, inpFF, hparams.eps);
+
+                // cur = mlp_ln_w*cur + mlp_ln_b
+                cur = ggml_mul(ctx0, cur, layer.norm2_w);
+                cur = ggml_add_inplace(ctx0, cur, layer.norm2_b);
+            }
+
+            // fully connected
+            cur = ggml_mul_mat(ctx0, layer.mlp_lin1_w, cur);
+            cur = ggml_add_inplace(ctx0, cur, layer.mlp_lin1_b);
+
+            // GELU activation
+            cur = ggml_gelu(ctx0, cur);
+
+            // projection
+            cur = ggml_mul_mat(ctx0, layer.mlp_lin2_w, cur);
+            cur = ggml_add_inplace(ctx0, cur, layer.mlp_lin2_b);
+        }
+
+        inpL = ggml_add(ctx0, cur, inpFF);
+    }
+
+    cur = ggml_cont(ctx0, ggml_permute(ctx0, inpL, 2, 0, 1, 3));
+
+    cur = ggml_conv_2d_sk_p0(ctx0, enc.neck_conv_0, cur);
+
+    cur = sam_layer_norm_2d(ctx0, cur, n_enc_out_chans, enc.neck_norm_0_w, enc.neck_norm_0_b, hparams.eps);
+
+    cur = ggml_conv_2d_s1_ph(ctx0, enc.neck_conv_1, cur);
+
+    cur = sam_layer_norm_2d(ctx0, cur, n_enc_out_chans, enc.neck_norm_1_w, enc.neck_norm_1_b, hparams.eps);
+
+    cur = ggml_cpy(ctx0, cur, state.embd_img);
+
+    ggml_build_forward_expand(gf, cur);
+    ggml_disconnect_node_from_graph(state.embd_img);
+
+    //ggml_graph_print(&gf);
+
+    ggml_free(ctx0);
+
+    ggml_gallocr_alloc_graph(state.allocr, gf);
+
+    {
+        struct ggml_tensor * inp = ggml_graph_get_tensor(gf, "inp");
+        float * data = (float *) ggml_get_data(inp);
+
+        const int nx = img.nx;
+        const int ny = img.ny;
+        const int n  = nx*ny;
+
+        GGML_ASSERT(nx == n_img_size && ny == n_img_size);
+
+        for (int k = 0; k < 3; k++) {
+            for (int y = 0; y < ny; y++) {
+                for (int x = 0; x < nx; x++) {
+                    data[k*n + y*nx + x] = img.data[3*(y*nx + x) + k];
+                }
+            }
+        }
+    }
+
+    return gf;
+}
+
+
+struct prompt_encoder_result {
+    struct ggml_tensor * embd_prompt_sparse = {};
+    struct ggml_tensor * embd_prompt_dense = {};
+};
+
+struct ggml_tensor * sam_prompt_encode_pe_encoding(
+        const sam_encoder_prompt & enc,
+        struct ggml_context      * ctx0,
+        struct ggml_cgraph       * gf,
+        struct ggml_tensor       * coords) {
+
+    auto * cur = ggml_mul_mat(ctx0, ggml_cont(ctx0, ggml_transpose(ctx0, enc.pe)), coords);
+    cur = ggml_scale(ctx0, cur, float(2.0*M_PI));
+
+    // concat
+    // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L192
+    {
+        struct ggml_tensor * t_sin = ggml_map_custom1(ctx0, cur, ggml_sam_sin, GGML_N_TASKS_MAX, NULL);
+        struct ggml_tensor * t_cos = ggml_map_custom1(ctx0, cur, ggml_sam_cos, GGML_N_TASKS_MAX, NULL);
+
+        cur = ggml_new_tensor_2d(ctx0, GGML_TYPE_F32, t_sin->ne[0] + t_cos->ne[0], cur->ne[1]);
+
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_sin, ggml_view_2d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], cur->nb[1], 0)));
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, t_cos, ggml_view_2d(ctx0, cur, t_sin->ne[0], t_sin->ne[1], cur->nb[1], t_sin->nb[1])));
+
+    }
+    return cur;
+
+}
+// encode a prompt
+//
+// - points
+// - boxes
+// - masks
+//
+// TODO: currently just encode a single point for simplicity
+//
+prompt_encoder_result sam_encode_prompt(
+        const sam_model     & model,
+        struct ggml_context * ctx0,
+        struct ggml_cgraph  * gf,
+                  sam_state & state,
+           const sam_prompt & prompt) {
+
+    const auto & hparams = model.hparams;
+    const auto & enc = model.enc_prompt;
+
+    struct ggml_tensor * inp = ggml_new_tensor_2d(ctx0, GGML_TYPE_F32, 2, 2);
+    ggml_set_name(inp, "prompt_input");
+    ggml_set_input(inp);
+
+    auto * embd_prompt_sparse = [&]() {
+        switch (prompt.prompt_type) {
+        case SAM_PROMPT_TYPE_POINT: {
+            // PromptEncoder._embed_points
+            auto * pt_embd  = sam_prompt_encode_pe_encoding(enc, ctx0, gf, inp);
+
+            // overwrite label == -1 with not_a_point_embed.weight
+            // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L86
+            // TODO: extend for multiple points
+            auto * pt_embd_not = ggml_view_2d(ctx0, pt_embd, pt_embd->ne[0], 1, pt_embd->nb[1], pt_embd->nb[1]);
+            ggml_build_forward_expand(gf, ggml_cpy(ctx0, enc.not_a_pt_embd_w, pt_embd_not));
+
+            // add point_embeddings[1] to label == 1
+            // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L90
+            auto * pt_embd1 = ggml_view_2d(ctx0, pt_embd, pt_embd->ne[0], 1, pt_embd->nb[1], 0);
+            ggml_build_forward_expand(gf,  ggml_add_inplace(ctx0, pt_embd1, enc.pt_embd[1]));
+
+            return pt_embd;
+        } break;
+        case SAM_PROMPT_TYPE_BOX: {
+            // PromptEncoder._embed_boxes
+            auto * corner_embd = sam_prompt_encode_pe_encoding(enc, ctx0, gf, inp);
+
+            // corner_embd[:, 0, :] += self.point_embeddings[2].weight
+            // corner_embd[:, 1, :] += self.point_embeddings[3].weight
+            auto * corner0 = ggml_view_2d(
+                ctx0, corner_embd, corner_embd->ne[0], 1, corner_embd->nb[1], 0);
+            auto * corner1 = ggml_view_2d(
+                ctx0, corner_embd, corner_embd->ne[0], 1, corner_embd->nb[1], corner_embd->nb[1]);
+
+            ggml_build_forward_expand(gf, ggml_add_inplace(ctx0, corner0, enc.pt_embd[2]));
+            ggml_build_forward_expand(gf, ggml_add_inplace(ctx0, corner1, enc.pt_embd[3]));
+
+            return corner_embd;
+        } break;
+        }
+    }();
+
+    ggml_build_forward_expand(gf, embd_prompt_sparse);
+
+    struct ggml_tensor * embd_prompt_dense = ggml_repeat(ctx0,
+            ggml_cont(ctx0,
+                ggml_view_3d(ctx0, enc.no_mask_embd_w,
+                    1, 1, enc.no_mask_embd_w->ne[0], enc.no_mask_embd_w->nb[0], enc.no_mask_embd_w->nb[0], 0)),
+            ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, hparams.n_img_embd(), hparams.n_img_embd(), hparams.n_enc_out_chans));
+
+    ggml_build_forward_expand(gf, embd_prompt_dense);
+
+    //printf("used_mem = %zu\n", ggml_used_mem(ctx0));
+
+    prompt_encoder_result res;
+    res.embd_prompt_sparse = embd_prompt_sparse;
+    res.embd_prompt_dense  = embd_prompt_dense;
+    return res;
+}
+
+struct ggml_tensor* sam_decode_mask_transformer_attn(
+    const sam_layer_dec_transformer_attn & attn,
+                      struct ggml_tensor * queries,
+                      struct ggml_tensor * keys,
+                      struct ggml_tensor * values,
+                     struct ggml_context * ctx0,
+                         const sam_model & model) {
+    const auto & hparams = model.hparams;
+    const int n_head = hparams.n_dec_heads;
+
+    struct ggml_tensor * Qcur = {};
+    struct ggml_tensor * Kcur = {};
+    struct ggml_tensor * Vcur = {};
+
+    Qcur = ggml_mul_mat(ctx0, attn.q_w, queries);
+    Qcur = ggml_add_inplace(ctx0, Qcur, attn.q_b);
+
+    Kcur = ggml_mul_mat(ctx0, attn.k_w, keys);
+    Kcur = ggml_add_inplace(ctx0, Kcur, attn.k_b);
+
+    Vcur = ggml_mul_mat(ctx0, attn.v_w, values);
+    Vcur = ggml_add_inplace(ctx0, Vcur, attn.v_b);
+
+    struct ggml_tensor * Q = {};
+    struct ggml_tensor * K = {};
+    struct ggml_tensor * V = {};
+
+    Q = ggml_reshape_4d(ctx0, Qcur, Qcur->ne[0]/n_head, n_head, Qcur->ne[1], Qcur->ne[2]);
+    Q = ggml_cont(ctx0, ggml_permute(ctx0, Q, 0, 2, 1, 3));
+
+    K = ggml_reshape_4d(ctx0, Kcur, Kcur->ne[0]/n_head, n_head, Kcur->ne[1], Kcur->ne[2]);
+    K = ggml_cont(ctx0, ggml_permute(ctx0, K, 0, 2, 1, 3));
+
+    V = ggml_reshape_4d(ctx0, Vcur, Vcur->ne[0]/n_head, n_head, Vcur->ne[1], Vcur->ne[2]);
+    V = ggml_cont(ctx0, ggml_permute(ctx0, V, 0, 2, 1, 3));
+
+    // Q * K
+    struct ggml_tensor * KQ = ggml_mul_mat(ctx0, K, Q);
+
+    struct ggml_tensor * KQ_scaled = ggml_scale_inplace(ctx0, KQ, 1.0f/sqrt(float(Q->ne[0])));
+
+    struct ggml_tensor * KQ_soft_max = ggml_soft_max_inplace(ctx0, KQ_scaled);
+
+    struct ggml_tensor * KQV = ggml_mul_mat(ctx0, KQ_soft_max, ggml_cont(ctx0, ggml_transpose(ctx0, V)));
+
+    struct ggml_tensor * KQV_merged = ggml_cont(ctx0, ggml_transpose(ctx0, KQV));
+    KQV_merged = ggml_cont(ctx0, ggml_permute(ctx0, KQV_merged, 0, 2, 1, 3));
+    KQV_merged = ggml_reshape_3d(ctx0, KQV_merged, KQV_merged->ne[0]*KQV_merged->ne[1], KQV_merged->ne[2], KQV_merged->ne[3]);
+    KQV_merged = ggml_mul_mat(ctx0, attn.out_w, KQV_merged);
+    KQV_merged = ggml_add_inplace(ctx0, KQV_merged, attn.out_b);
+
+    return KQV_merged;
+}
+
+struct ggml_tensor * sam_decode_mask_mlp_relu_3(
+     struct ggml_tensor * in,
+     struct ggml_tensor * w_0,
+     struct ggml_tensor * b_0,
+     struct ggml_tensor * w_1,
+     struct ggml_tensor * b_1,
+     struct ggml_tensor * w_2,
+     struct ggml_tensor * b_2,
+    struct ggml_context * ctx0) {
+
+    struct ggml_tensor * cur = {};
+    cur = ggml_mul_mat(ctx0, w_0, in);
+    cur = ggml_add_inplace(ctx0, cur, b_0);
+
+    cur = ggml_relu_inplace(ctx0, cur);
+
+    cur = ggml_mul_mat(ctx0, w_1, cur);
+    cur = ggml_add_inplace(ctx0, cur, b_1);
+
+    cur = ggml_relu_inplace(ctx0, cur);
+
+    cur = ggml_mul_mat(ctx0, w_2, cur);
+    cur = ggml_add_inplace(ctx0, cur, b_2);
+
+    return cur;
+}
+
+bool sam_decode_mask(
+                    const sam_model & model,
+        const prompt_encoder_result & prompt,
+                 struct ggml_tensor * pe_img,
+                struct ggml_context * ctx0,
+                struct ggml_cgraph  * gf,
+                          sam_state & state,
+                         const bool   multimask_output) {
+
+    const auto & hparams = model.hparams;
+    const auto & dec = model.dec;
+    const int n_img_embd = hparams.n_img_embd();
+
+    struct ggml_tensor * tokens = {};
+    {
+        // Concatenate output tokens
+        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L120
+        const auto& sparse = prompt.embd_prompt_sparse;
+
+        tokens = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, dec.iou_token_w->ne[0], dec.iou_token_w->ne[1] + dec.mask_tokens_w->ne[1] + sparse->ne[1], sparse->ne[2]);
+
+        const size_t offsets[3] = { 0, dec.iou_token_w->ne[1]*tokens->nb[1], dec.iou_token_w->ne[1]*tokens->nb[1] + dec.mask_tokens_w->ne[1]*tokens->nb[1] };
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, dec.iou_token_w,   ggml_view_2d(ctx0, tokens, tokens->ne[0], dec.iou_token_w->ne[1],   tokens->nb[1], offsets[0])));
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, dec.mask_tokens_w, ggml_view_2d(ctx0, tokens, tokens->ne[0], dec.mask_tokens_w->ne[1], tokens->nb[1], offsets[1])));
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, sparse,            ggml_view_2d(ctx0, tokens, tokens->ne[0], sparse->ne[1],            tokens->nb[1], offsets[2])));
+        // TODO: Sparse prompt embeddings can have more than one point
+    }
+
+
+    struct ggml_tensor * src = {};
+    struct ggml_tensor * pos_src = {};
+    int srcNE[4] = { 0, 0, 0, 0 };
+    {
+        // Expand per-image data in the batch direction to be per-mask
+        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L125
+        src = ggml_new_tensor_4d(ctx0, GGML_TYPE_F32, state.embd_img->ne[0], state.embd_img->ne[1], state.embd_img->ne[2], tokens->ne[2]);
+
+        src = ggml_add(ctx0,
+            ggml_repeat(ctx0,
+                state.embd_img,
+                src),
+            prompt.embd_prompt_dense);
+
+        srcNE[0] = src->ne[0];
+        srcNE[1] = src->ne[1];
+        srcNE[2] = src->ne[2];
+        srcNE[3] = src->ne[3];
+
+        // flatten & permute
+        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L83
+        src = ggml_cont(ctx0, ggml_permute(ctx0,
+            ggml_view_3d(ctx0,
+                src,
+                src->ne[0]*src->ne[1],
+                src->ne[2],
+                src->ne[3],
+                src->nb[2],
+                src->nb[3],
+                0),
+            1, 0, 2, 3));
+
+        pos_src = ggml_new_tensor_4d(ctx0, GGML_TYPE_F32, pe_img->ne[0], pe_img->ne[1], pe_img->ne[2], tokens->ne[2]);
+        pos_src = ggml_repeat(ctx0,
+            pe_img,
+            pos_src);
+
+        // flatten & permute
+        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L83
+        pos_src = ggml_cont(ctx0, ggml_permute(ctx0,
+            ggml_view_3d(ctx0,
+                pos_src,
+                pos_src->ne[0]*pos_src->ne[1],
+                pos_src->ne[2],
+                pos_src->ne[3],
+                pos_src->nb[2],
+                pos_src->nb[3],
+                0),
+            1, 0, 2, 3));
+    }
+
+    struct ggml_tensor * queries = tokens;
+    struct ggml_tensor * keys = src;
+    {
+        // Run the transformer
+        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L62
+        for (int i = 0; i < int(model.dec.transformer_layers.size()); ++i) {
+            const auto& tfm_layer = model.dec.transformer_layers[i];
+
+            // Self attention block
+            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L154
+            const bool skip_first_layer_pe = i == 0;
+            if (skip_first_layer_pe) {
+                queries = sam_decode_mask_transformer_attn(tfm_layer.self_attn, queries, queries, queries, ctx0, model);
+            }
+            else {
+                struct ggml_tensor * q_0 = ggml_add(ctx0, queries, tokens);
+
+                struct ggml_tensor * self_attn = sam_decode_mask_transformer_attn(tfm_layer.self_attn, q_0, q_0, queries, ctx0, model);
+                queries = ggml_add(ctx0, queries, self_attn);
+            }
+
+            queries = ggml_norm(ctx0, queries, hparams.eps_decoder_transformer);
+            queries = ggml_add_inplace(ctx0,
+                    ggml_mul(ctx0, queries, tfm_layer.norm1_w),
+                    tfm_layer.norm1_b);
+
+            // Cross attention block, tokens attending to image embedding
+            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L163
+            struct ggml_tensor * q_1 = ggml_add(ctx0, queries, tokens);
+            struct ggml_tensor * k_1 = ggml_add(ctx0, keys, pos_src);
+
+            struct ggml_tensor * cross_attn_token_to_img = sam_decode_mask_transformer_attn(tfm_layer.cross_attn_token_to_img, q_1, k_1, keys, ctx0, model);
+
+            queries = ggml_add_inplace(ctx0, queries, cross_attn_token_to_img);
+            queries = ggml_norm_inplace(ctx0, queries, hparams.eps_decoder_transformer);
+            queries = ggml_add_inplace(ctx0,
+                    ggml_mul(ctx0, queries, tfm_layer.norm2_w),
+                    tfm_layer.norm2_b);
+
+            // MLP block
+            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L170
+            struct ggml_tensor * mlp_out = ggml_mul_mat(ctx0,
+                tfm_layer.mlp_lin1_w,
+                queries);
+
+            mlp_out = ggml_add_inplace(ctx0, mlp_out, tfm_layer.mlp_lin1_b);
+
+            // RELU activation
+            mlp_out = ggml_relu_inplace(ctx0, mlp_out);
+            mlp_out = ggml_mul_mat(ctx0, tfm_layer.mlp_lin2_w, mlp_out);
+
+            mlp_out = ggml_add_inplace(ctx0, mlp_out, tfm_layer.mlp_lin2_b);
+
+            queries = ggml_add_inplace(ctx0, queries, mlp_out);
+            queries = ggml_norm_inplace(ctx0, queries, hparams.eps_decoder_transformer);
+            queries = ggml_add_inplace(ctx0,
+                    ggml_mul(ctx0, queries, tfm_layer.norm3_w),
+                    tfm_layer.norm3_b);
+
+            // Cross attention block, image embedding attending to tokens
+            // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L175
+            struct ggml_tensor * q_2 = ggml_add(ctx0, queries, tokens);
+            struct ggml_tensor * k_2 = ggml_add(ctx0, keys, pos_src);
+
+            struct ggml_tensor * cross_attn_img_to_token = sam_decode_mask_transformer_attn(tfm_layer.cross_attn_img_to_token, k_2, q_2, queries, ctx0, model);
+            keys = ggml_add_inplace(ctx0, keys, cross_attn_img_to_token);
+            keys = ggml_norm_inplace(ctx0, keys, hparams.eps_decoder_transformer);
+            keys = ggml_add_inplace(ctx0,
+                    ggml_mul(ctx0, keys, tfm_layer.norm4_w),
+                    tfm_layer.norm4_b);
+        }
+
+        // Apply the final attention layer from the points to the image
+        // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/transformer.py#L99
+        struct ggml_tensor * q = ggml_add(ctx0, queries, tokens);
+        struct ggml_tensor * k = ggml_add(ctx0, keys, pos_src);
+
+        struct ggml_tensor * final_attn_token_to_img = sam_decode_mask_transformer_attn(dec.transformer_final_attn_token_to_img, q, k, keys, ctx0, model);
+
+        queries = ggml_add_inplace(ctx0, queries, final_attn_token_to_img);
+        queries = ggml_norm_inplace(ctx0, queries, hparams.eps_decoder_transformer);
+        queries = ggml_add_inplace(ctx0,
+                ggml_mul(ctx0, queries, dec.transformer_norm_final_w),
+                dec.transformer_norm_final_b);
+    }
+
+
+    struct ggml_tensor * iou_pred = ggml_view_2d(ctx0, queries, queries->ne[0], queries->ne[2], queries->nb[2], 0);
+    const int num_mask_tokens = 4; // num_multimask_outputs + 1
+    struct ggml_tensor * mask_tokens_out = ggml_view_3d(ctx0, queries, queries->ne[0], num_mask_tokens, queries->ne[2], queries->nb[1], num_mask_tokens*queries->nb[1], queries->nb[1]);
+
+    // Upscale mask embeddings and predict masks using the mask tokens
+    // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L136
+    keys = ggml_cont(ctx0, ggml_transpose(ctx0, keys));
+    keys = ggml_view_4d(ctx0, keys, srcNE[0], srcNE[1], srcNE[2], srcNE[3], srcNE[0]*keys->nb[0], keys->nb[1], keys->nb[2], 0);
+    // ggml_build_forward_expand(gf, keys);
+    struct ggml_tensor * upscaled_embedding = {};
+    {
+        // ConvTranspose2d
+        keys = ggml_conv_transpose_2d_p0(ctx0, dec.output_upscaling_0_w, keys, 2);
+        keys = ggml_add_inplace(ctx0, keys, ggml_repeat(ctx0,
+                                     ggml_reshape_3d(ctx0, dec.output_upscaling_0_b, 1, 1, dec.output_upscaling_0_b->ne[0]),
+                                     keys));
+
+        keys = sam_layer_norm_2d(ctx0, keys, n_img_embd, dec.output_upscaling_1_w, dec.output_upscaling_1_b, hparams.eps);
+
+        // GELU activation
+        keys = ggml_gelu_inplace(ctx0, keys);
+
+        // ConvTranspose2d
+        keys = ggml_conv_transpose_2d_p0(ctx0, dec.output_upscaling_3_w, keys, 2);
+        keys = ggml_add_inplace(ctx0, ggml_repeat(ctx0,
+                                ggml_reshape_3d(ctx0, dec.output_upscaling_3_b, 1, 1, dec.output_upscaling_3_b->ne[0]),
+                                keys), keys);
+        // GELU activation
+        keys = ggml_gelu_inplace(ctx0, keys);
+        upscaled_embedding = ggml_reshape_3d(ctx0, keys, keys->ne[0]*keys->ne[1], keys->ne[2], keys->ne[3]);
+        upscaled_embedding = ggml_cont(ctx0, ggml_transpose(ctx0, upscaled_embedding)); // TODO: Shouldn't be needed
+    }
+
+    struct ggml_tensor * hyper_in = ggml_new_tensor_3d(ctx0, GGML_TYPE_F32, n_img_embd/2, num_mask_tokens, mask_tokens_out->ne[2]);
+
+    for (int i = 0; i < num_mask_tokens; ++i) {
+        const auto& mlp = dec.output_hypernet_mlps[i];
+        struct ggml_tensor * in = ggml_view_2d(ctx0, mask_tokens_out, mask_tokens_out->ne[0], mask_tokens_out->ne[2], mask_tokens_out->nb[1], i*mask_tokens_out->nb[1]);
+        struct ggml_tensor * out = sam_decode_mask_mlp_relu_3(in, mlp.w_0, mlp.b_0, mlp.w_1, mlp.b_1, mlp.w_2, mlp.b_2, ctx0);
+        ggml_build_forward_expand(gf, ggml_cpy(ctx0, out, ggml_view_2d(ctx0, hyper_in, hyper_in->ne[0], hyper_in->ne[2], hyper_in->nb[1], i*hyper_in->nb[1])));
+    }
+
+    struct ggml_tensor * masks = ggml_mul_mat(ctx0, hyper_in, upscaled_embedding);
+    masks = ggml_cont(ctx0, ggml_transpose(ctx0, masks)); // TODO: Shouldn't be needed
+    masks = ggml_reshape_4d(ctx0, masks, keys->ne[0], keys->ne[1], masks->ne[1], keys->ne[3]);
+
+    // Generate mask quality predictions
+    // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L146
+    iou_pred = sam_decode_mask_mlp_relu_3(iou_pred, dec.iou_prediction_head_0_w, dec.iou_prediction_head_0_b, dec.iou_prediction_head_1_w, dec.iou_prediction_head_1_b, dec.iou_prediction_head_2_w, dec.iou_prediction_head_2_b, ctx0);
+
+    // Select the correct mask or masks for output
+    // ref: https://github.com/facebookresearch/segment-anything/blob/6fdee8f2727f4506cfbbe553e23b895e27956588/segment_anything/modeling/mask_decoder.py#L101
+    if (multimask_output) {
+        iou_pred = ggml_cpy(state.ctx, ggml_view_1d(ctx0, iou_pred, iou_pred->ne[0] - 1, iou_pred->nb[0]), state.iou_predictions);
+        masks = ggml_view_4d(ctx0, masks, masks->ne[0], masks->ne[1], masks->ne[2] - 1, masks->ne[3],
+                                        masks->nb[1], masks->nb[2], masks->nb[3], masks->nb[2] /* offset*/);
+        masks = ggml_cpy(state.ctx, masks, state.low_res_masks);
+    } else {
+        iou_pred = ggml_cpy(state.ctx, ggml_view_1d(ctx0, iou_pred, 1, 0), ggml_view_1d(ctx0, state.iou_predictions, 1, 0));
+        masks = ggml_view_4d(ctx0, masks, masks->ne[0], masks->ne[1], 1, masks->ne[3],
+                                        masks->nb[1], masks->nb[2], masks->nb[3], 0);
+        auto * low_res_mask = ggml_view_4d(ctx0, state.low_res_masks, masks->ne[0], masks->ne[1], 1, masks->ne[3],
+                                        masks->nb[1], masks->nb[2], masks->nb[3], 0);
+        masks = ggml_cpy(state.ctx, masks, low_res_mask);
+    }
+
+    ggml_build_forward_expand(gf, masks);
+    ggml_build_forward_expand(gf, iou_pred);
+
+    ggml_disconnect_node_from_graph(state.low_res_masks);
+    ggml_disconnect_node_from_graph(state.iou_predictions);
+
+    return true;
+}
+
+bool sam_write_masks(const sam_hparams& hparams, int nx, int ny, const sam_state & state, const std::string & fname, const bool multimask_output) {
+    if (state.low_res_masks->ne[2] == 0) return true;
+    if (state.low_res_masks->ne[2] != state.iou_predictions->ne[0]) {
+        printf("Error: number of masks (%d) does not match number of iou predictions (%d)\n", (int)state.low_res_masks->ne[2], (int)state.iou_predictions->ne[0]);
+        return false;
+    }
+
+    const int n_img_size = hparams.n_img_size();
+    const float mask_threshold = hparams.mask_threshold;
+    const float iou_threshold = hparams.iou_threshold;
+    const float stability_score_threshold = hparams.stability_score_threshold;
+    const float intersection_threshold = mask_threshold + hparams.stability_score_offset;
+    const float union_threshold = mask_threshold - hparams.stability_score_offset;
+
+    const int ne0 = state.low_res_masks->ne[0];
+    const int ne1 = state.low_res_masks->ne[1];
+    const int ne2 = multimask_output ? state.low_res_masks->ne[2] : 1;
+
+    // Remove padding and upscale masks to the original image size.
+    // ref: https://github.com/facebookresearch/segment-anything/blob/efeab7296ab579d4a261e554eca80faf6b33924a/segment_anything/modeling/sam.py#L140
+
+    const float preprocess_scale = std::max(nx, ny) / float(n_img_size);
+    const int cropped_nx = int(nx / preprocess_scale + 0.5f);
+    const int cropped_ny = int(ny / preprocess_scale + 0.5f);
+
+    const float scale_x_1 = (float)ne0 / (float)n_img_size;
+    const float scale_y_1 = (float)ne1 / (float)n_img_size;
+
+    const float scale_x_2 = float(cropped_nx) / float(nx);
+    const float scale_y_2 = float(cropped_ny) / float(ny);
+
+    const auto iou_data = (float*)state.iou_predictions->data;
+
+    for (int i = 0; i < ne2; ++i) {
+        if (iou_threshold > 0.f && iou_data[i] < iou_threshold) {
+            printf("Skipping mask %d with iou %f below threshold %f\n", i, iou_data[i], iou_threshold);
+            continue; // Filtering masks with iou below the threshold
+        }
+
+        std::vector<float> mask_data(n_img_size*n_img_size);
+        {
+            const float* data = (float *) state.low_res_masks->data + i*ne0*ne1;
+
+            for (int iy = 0; iy < n_img_size; ++iy) {
+                for (int ix = 0; ix < n_img_size; ++ix) {
+                    const float sx = std::max(scale_x_1*(ix + 0.5f) - 0.5f, 0.0f);
+                    const float sy = std::max(scale_y_1*(iy + 0.5f) - 0.5f, 0.0f);
+
+                    const int x0 = std::max(0, (int)sx);
+                    const int y0 = std::max(0, (int)sy);
+
+                    const int x1 = std::min(x0 + 1, ne0 - 1);
+                    const int y1 = std::min(y0 + 1, ne1 - 1);
+
+                    const float dx = sx - x0;
+                    const float dy = sy - y0;
+
+                    const int j00 = y0*ne0 + x0;
+                    const int j01 = y0*ne0 + x1;
+                    const int j10 = y1*ne0 + x0;
+                    const int j11 = y1*ne0 + x1;
+
+                    const float v00 = data[j00];
+                    const float v01 = data[j01];
+                    const float v10 = data[j10];
+                    const float v11 = data[j11];
+
+                    const float v0 = (1-dx)*v00 + dx*v01;
+                    const float v1 = (1-dx)*v10 + dx*v11;
+
+                    const float v = (1-dy)*v0 + dy*v1;
+
+                    mask_data[iy*n_img_size + ix] = v;
+                }
+            }
+        }
+
+        int intersections = 0;
+        int unions = 0;
+        sam_image_u8 res;
+        int min_iy = ny;
+        int max_iy = 0;
+        int min_ix = nx;
+        int max_ix = 0;
+        {
+            const float* data = mask_data.data();
+
+            res.nx = nx;
+            res.ny = ny;
+            res.data.resize(nx*ny);
+
+            for (int iy = 0; iy < ny; ++iy) {
+                for (int ix = 0; ix < nx; ++ix) {
+                    const float sx = std::max(scale_x_2*(ix + 0.5f) - 0.5f, 0.0f);
+                    const float sy = std::max(scale_y_2*(iy + 0.5f) - 0.5f, 0.0f);
+
+                    const int x0 = std::max(0, (int)sx);
+                    const int y0 = std::max(0, (int)sy);
+
+                    const int x1 = std::min(x0 + 1, cropped_nx - 1);
+                    const int y1 = std::min(y0 + 1, cropped_ny - 1);
+
+                    const float dx = sx - x0;
+                    const float dy = sy - y0;
+
+                    const int j00 = y0*n_img_size + x0;
+                    const int j01 = y0*n_img_size + x1;
+                    const int j10 = y1*n_img_size + x0;
+                    const int j11 = y1*n_img_size + x1;
+
+                    const float v00 = data[j00];
+                    const float v01 = data[j01];
+                    const float v10 = data[j10];
+                    const float v11 = data[j11];
+
+                    const float v0 = (1-dx)*v00 + dx*v01;
+                    const float v1 = (1-dx)*v10 + dx*v11;
+
+                    const float v = (1-dy)*v0 + dy*v1;
+
+                    if (v > intersection_threshold) {
+                        intersections++;
+                    }
+                    if (v > union_threshold) {
+                        unions++;
+                    }
+                    if (v > mask_threshold) {
+                        min_iy = std::min(min_iy, iy);
+                        max_iy = std::max(max_iy, iy);
+                        min_ix = std::min(min_ix, ix);
+                        max_ix = std::max(max_ix, ix);
+
+                        res.data[iy*nx + ix] = 255;
+                    }
+                }
+            }
+        }
+
+        const float stability_score = float(intersections) / float(unions);
+        if (stability_score_threshold > 0.f && stability_score < stability_score_threshold) {
+            printf("Skipping mask %d with stability score %f below threshold %f\n", i, stability_score, stability_score_threshold);
+            continue; // Filtering masks with stability score below the threshold
+        }
+
+        printf("Mask %d: iou = %f, stability_score = %f, bbox (%d, %d), (%d, %d)\n",
+                i, iou_data[i], stability_score, min_ix, max_ix, min_iy, max_iy);
+
+        const std::string filename = multimask_output ? fname + std::to_string(i) + ".png" : fname + ".png";
+        if (!stbi_write_png(filename.c_str(), res.nx, res.ny, 1, res.data.data(), res.nx)) {
+            printf("%s: failed to write mask %s\n", __func__, filename.c_str());
+            return false;
+        }
+    }
+
+
+    return true;
+}
+
+
+struct ggml_cgraph  * sam_build_fast_graph(
+        const sam_model  & model,
+               sam_state & state,
+               const int   nx,
+               const int   ny,
+        const sam_prompt & prompt,
+              const bool   multimask_output) {
+
+    struct ggml_init_params ggml_params = {
+        /*.mem_size   =*/ state.buf_compute_fast.size(),
+        /*.mem_buffer =*/ state.buf_compute_fast.data(),
+        /*.no_alloc   =*/ true, // skip allocating as we use ggml_alloc to allocate exact memory requirements
+    };
+
+    struct ggml_context * ctx0   = ggml_init(ggml_params);
+    struct ggml_cgraph  * gf     = ggml_new_graph(ctx0);
+
+    prompt_encoder_result enc_res = sam_encode_prompt(model, ctx0, gf, state, prompt);
+    if (!enc_res.embd_prompt_sparse || !enc_res.embd_prompt_dense) {
+        fprintf(stderr, "%s: failed to encode prompt\n", __func__);
+        return {};
+    }
+
+    struct ggml_tensor * pe_img_dense = sam_fill_dense_pe(model, ctx0, gf, state);
+    if (!pe_img_dense) {
+        fprintf(stderr, "%s: failed to get dense positional encoding\n", __func__);
+        return {};
+    }
+
+    if (!sam_decode_mask(model, enc_res, pe_img_dense, ctx0, gf, state, multimask_output)) {
+         fprintf(stderr, "%s: failed to decode mask\n", __func__);
+         return {};
+    }
+
+    ggml_free(ctx0);
+
+    ggml_gallocr_alloc_graph(state.allocr, gf);
+
+    struct ggml_tensor * inp = ggml_graph_get_tensor(gf, "prompt_input");
+    auto * data = (float *) inp->data;
+
+    // Transform prompt (point or box)
+    {
+        // https://github.com/facebookresearch/segment-anything/blob/dca509fe793f601edb92606367a655c15ac00fdf/segment_anything/utils/transforms.py#L33
+        // The point scaling here is greatly simplified but mathematically equivalent.
+        const auto scale = 1.0F / std::max(nx, ny);
+
+        switch (prompt.prompt_type) {
+        case SAM_PROMPT_TYPE_POINT: {
+            const auto & pt = prompt.pt;
+
+            // set the input by converting the [0, 1] coordinates to [-1, 1]
+            data[0] = 2.0f*pt.x*scale - 1.0f;
+            data[1] = 2.0f*pt.y*scale - 1.0f;
+
+            // padding
+            // ref: https://github.com/facebookresearch/segment-anything/blob/main/segment_anything/modeling/prompt_encoder.py#L81-L85
+            data[2] = 2.0f*(0.0f) - 1.0f;
+            data[3] = 2.0f*(0.0f) - 1.0f;
+        } break;
+        case SAM_PROMPT_TYPE_BOX: {
+            const auto & box = prompt.box;
+
+            data[0] = 2.0f*box.x1*scale - 1.0f;
+            data[1] = 2.0f*box.y1*scale - 1.0f;
+            data[2] = 2.0f*box.x2*scale - 1.0f;
+            data[3] = 2.0f*box.y2*scale - 1.0f;
+        } break;
+        }
+    }
+
+    // from sam_fill_dense_pe
+    {
+        struct ggml_tensor * xy_embed_stacked = ggml_graph_get_tensor(gf, "xy_embed_stacked");
+        const int32_t n_img_embd = model.hparams.n_img_embd();
+        const float n_img_embd_inv = 1.0f / n_img_embd;
+        float * data = (float *) ggml_get_data(xy_embed_stacked);
+        for (int i = 0; i < n_img_embd; ++i) {
+            const int row = 2*i*n_img_embd;
+            const float y_val = 2 * (i + 0.5f) * n_img_embd_inv - 1;
+            for (int j = 0; j < n_img_embd; ++j) {
+                const float x_val = 2 * (j + 0.5f) * n_img_embd_inv - 1;
+                data[row + 2*j + 0] = x_val;
+                data[row + 2*j + 1] = y_val;
+            }
+        }
+    }
+
+    return gf;
+}
+
+void sam_print_usage(int argc, char ** argv, const sam_params & params) {
+    fprintf(stderr, "usage: %s [options]\n", argv[0]);
+    fprintf(stderr, "\n");
+    fprintf(stderr, "options:\n");
+    fprintf(stderr, "  -h, --help            show this help message and exit\n");
+    fprintf(stderr, "  -s SEED, --seed SEED  RNG seed (default: -1)\n");
+    fprintf(stderr, "  -t N, --threads N     number of threads to use during computation (default: %d)\n", params.n_threads);
+    fprintf(stderr, "  -m FNAME, --model FNAME\n");
+    fprintf(stderr, "                        model path (default: %s)\n", params.model.c_str());
+    fprintf(stderr, "  -i FNAME, --inp FNAME\n");
+    fprintf(stderr, "                        input file (default: %s)\n", params.fname_inp.c_str());
+    fprintf(stderr, "  -o FNAME, --out FNAME\n");
+    fprintf(stderr, "                        mask file name prefix (default: %s)\n", params.fname_out.c_str());
+    fprintf(stderr, "  -sm, --single-mask\n");
+    fprintf(stderr, "                        single mask output (default multi mask output)\n");
+    fprintf(stderr, "SAM hyperparameters:\n");
+    fprintf(stderr, "  -mt FLOAT, --mask-threshold\n");
+    fprintf(stderr, "                        mask threshold (default: %f)\n", params.mask_threshold);
+    fprintf(stderr, "  -it FLOAT, --iou-threshold\n");
+    fprintf(stderr, "                        iou threshold (default: %f)\n", params.iou_threshold);
+    fprintf(stderr, "  -st FLOAT, --score-threshold\n");
+    fprintf(stderr, "                        score threshold (default: %f)\n", params.stability_score_threshold);
+    fprintf(stderr, "  -so FLOAT, --score-offset\n");
+    fprintf(stderr, "                        score offset (default: %f)\n", params.stability_score_offset);
+    fprintf(stderr, "  -e FLOAT, --epsilon\n");
+    fprintf(stderr, "                        epsilon (default: %f)\n", params.eps);
+    fprintf(stderr, "  -ed FLOAT, --epsilon-decoder-transformer\n");
+    fprintf(stderr, "                        epsilon decoder transformer (default: %f)\n", params.eps_decoder_transformer);
+    fprintf(stderr, "SAM prompt:\n");
+    fprintf(stderr, "  -p [x,y], --point-prompt\n");
+    fprintf(stderr, "                        point to be used as prompt for SAM (default: %f,%f). Must be in a format FLOAT,FLOAT \n", params.prompt.pt.x, params.prompt.pt.y);
+    fprintf(stderr, "  -b [x1,y1,x2,y2], --box-prompt\n");
+    fprintf(stderr, "                        box to be used as prompt for SAM (default: %f,%f,%f,%f). Must be in a format FLOAT,FLOAT,FLOAT,FLOAT \n",
+        params.prompt.box.x1, params.prompt.box.y1, params.prompt.box.x2, params.prompt.box.y2);
+    fprintf(stderr, "\n");
+}
+
+bool sam_params_parse(int argc, char ** argv, sam_params & params) {
+
+    bool use_point_prompt = false;
+    bool use_box_prompt = false;
+
+    for (int i = 1; i < argc; i++) {
+        std::string arg = argv[i];
+
+        if (arg == "-s" || arg == "--seed") {
+            params.seed = std::stoi(argv[++i]);
+        } else if (arg == "-t" || arg == "--threads") {
+            params.n_threads = std::stoi(argv[++i]);
+        } else if (arg == "-m" || arg == "--model") {
+            params.model = argv[++i];
+        } else if (arg == "-i" || arg == "--inp") {
+            params.fname_inp = argv[++i];
+        } else if (arg == "-o" || arg == "--out") {
+            params.fname_out = argv[++i];
+        } else if (arg == "-sm" || arg == "--single-mask") {
+            params.multimask_output = false;
+        } else if (arg == "-mt" || arg == "--mask-threshold") {
+            params.mask_threshold = std::stof(argv[++i]);
+        } else if (arg == "-it" || arg == "--iou-threshold") {
+            params.iou_threshold = std::stof(argv[++i]);
+        } else if (arg == "-st" || arg == "--score-threshold") {
+            params.stability_score_threshold = std::stof(argv[++i]);
+        } else if (arg == "-so" || arg == "--score-offset") {
+            params.stability_score_offset = std::stof(argv[++i]);
+        } else if (arg == "-e" || arg == "--epsilon") {
+            params.eps = std::stof(argv[++i]);
+        } else if (arg == "-ed" || arg == "--epsilon-decoder-transformer") {
+            params.eps_decoder_transformer = std::stof(argv[++i]);
+        } else if (arg == "-p" || arg == "--point-prompt") {
+            // TODO multiple points per model invocation
+            use_point_prompt = true;
+            char* point = argv[++i];
+
+            char* coord = strtok(point, ",");
+            if (!coord){
+                fprintf(stderr, "Error while parsing prompt!\n");
+                exit(1);
+            }
+            params.prompt.pt.x = std::stof(coord);
+
+            coord = strtok(NULL, ",");
+            if (!coord){
+                fprintf(stderr, "Error while parsing prompt!\n");
+                exit(1);
+            }
+            params.prompt.pt.y = std::stof(coord);
+        } else if (arg == "-b" || arg == "--box-prompt") {
+            use_box_prompt = true;
+            char * box_prompt = argv[++i];
+            float box_vals[4];
+
+            char * val = strtok(box_prompt, ",");
+            if (!val) {
+                fprintf(stderr, "Error while parsing prompt!\n");
+                exit(1);
+            }
+            box_vals[0] = std::stof(val);
+
+            for (int j = 1; j < 4; ++j) {
+                char * val = strtok(NULL, ",");
+                if (!val) {
+                    fprintf(stderr, "Error while parsing prompt!\n");
+                    exit(1);
+                }
+                box_vals[j] = std::stof(val);
+            }
+
+            params.prompt.box.x1 = box_vals[0];
+            params.prompt.box.y1 = box_vals[1];
+            params.prompt.box.x2 = box_vals[2];
+            params.prompt.box.y2 = box_vals[3];
+        } else if (arg == "-h" || arg == "--help") {
+            sam_print_usage(argc, argv, params);
+            exit(0);
+        } else {
+            fprintf(stderr, "error: unknown argument: %s\n", arg.c_str());
+            sam_print_usage(argc, argv, params);
+            exit(0);
+        }
+    }
+
+    if (use_box_prompt && use_point_prompt) {
+        fprintf(stderr, "Error: use either point or box prompt, not both.\n");
+        exit(1);
+    }
+
+    params.prompt.prompt_type = SAM_PROMPT_TYPE_POINT;
+    if (use_box_prompt) {
+        params.prompt.prompt_type = SAM_PROMPT_TYPE_BOX;
+    }
+
+    return true;
+}
+
+
+int main(int argc, char ** argv) {
+    const int64_t t_main_start_us = ggml_time_us();
+
+    sam_params params;
+    params.model = "models/sam-vit-b/ggml-model-f16.bin";
+
+    sam_model model;
+    sam_state state;
+    int64_t t_load_us = 0;
+
+    if (sam_params_parse(argc, argv, params) == false) {
+        return 1;
+    }
+
+    if (params.seed < 0) {
+        params.seed = time(NULL);
+    }
+    fprintf(stderr, "%s: seed = %d\n", __func__, params.seed);
+
+    // load the image
+    sam_image_u8 img0;
+    if (!sam_image_load_from_file(params.fname_inp, img0)) {
+        fprintf(stderr, "%s: failed to load image from '%s'\n", __func__, params.fname_inp.c_str());
+        return 1;
+    }
+    fprintf(stderr, "%s: loaded image '%s' (%d x %d)\n", __func__, params.fname_inp.c_str(), img0.nx, img0.ny);
+
+    // preprocess to f32
+    sam_image_f32 img1;
+    if (!sam_image_preprocess(img0, img1)) {
+        fprintf(stderr, "%s: failed to preprocess image\n", __func__);
+        return 1;
+    }
+    fprintf(stderr, "%s: preprocessed image (%d x %d)\n", __func__, img1.nx, img1.ny);
+
+
+    // load the model
+    {
+        const int64_t t_start_us = ggml_time_us();
+
+        if (!sam_model_load(params, model)) {
+            fprintf(stderr, "%s: failed to load model from '%s'\n", __func__, params.model.c_str());
+            return 1;
+        }
+
+        t_load_us = ggml_time_us() - t_start_us;
+    }
+
+    {
+        static size_t buf_size = 256u*1024*1024;
+
+        struct ggml_init_params ggml_params = {
+            /*.mem_size   =*/ buf_size,
+            /*.mem_buffer =*/ NULL,
+            /*.no_alloc   =*/ false,
+        };
+
+        state.ctx = ggml_init(ggml_params);
+
+        state.embd_img = ggml_new_tensor_3d(state.ctx, GGML_TYPE_F32,
+                model.hparams.n_img_embd(), model.hparams.n_img_embd(), model.hparams.n_enc_out_chans);
+
+        state.low_res_masks = ggml_new_tensor_3d(state.ctx, GGML_TYPE_F32,
+                model.hparams.n_enc_out_chans, model.hparams.n_enc_out_chans, 3);
+
+        state.iou_predictions = ggml_new_tensor_1d(state.ctx, GGML_TYPE_F32, 3);
+    }
+
+    // Encode image
+    {
+        state.buf_compute_img_enc.resize(ggml_tensor_overhead()*GGML_DEFAULT_GRAPH_SIZE + ggml_graph_overhead());
+        state.allocr = ggml_gallocr_new(ggml_backend_cpu_buffer_type());
+
+        struct ggml_cgraph  * gf = sam_encode_image(model, state, img1);
+        if (!gf) {
+            fprintf(stderr, "%s: failed to encode image\n", __func__);
+            return 1;
+        }
+
+        ggml_graph_compute_helper(state.work_buffer, gf, params.n_threads);
+
+        // print_t_f32("embd_img", state.embd_img);
+
+        ggml_gallocr_free(state.allocr);
+        state.allocr = NULL;
+        state.work_buffer.clear();
+    }
+
+    // Encode prompt and decode mask
+    {
+        state.buf_compute_fast.resize(ggml_tensor_overhead()*GGML_DEFAULT_GRAPH_SIZE + ggml_graph_overhead());
+        state.allocr = ggml_gallocr_new(ggml_backend_cpu_buffer_type());
+
+        switch (params.prompt.prompt_type) {
+        case SAM_PROMPT_TYPE_POINT:
+            fprintf(stderr, "Using point prompt: (%f, %f)\n", params.prompt.pt.x, params.prompt.pt.y);
+            break;
+        case SAM_PROMPT_TYPE_BOX:
+            fprintf(stderr, "Using box prompt: (%f, %f, %f, %f)\n",
+                params.prompt.box.x1,
+                params.prompt.box.y1,
+                params.prompt.box.x2,
+                params.prompt.box.y2);
+            break;
+        }
+
+        struct ggml_cgraph * gf = sam_build_fast_graph(model, state, img0.nx, img0.ny, params.prompt, params.multimask_output);
+        if (!gf) {
+            fprintf(stderr, "%s: failed to build fast graph\n", __func__);
+            return 1;
+        }
+
+        ggml_graph_compute_helper(state.work_buffer, gf, params.n_threads);
+
+        //print_t_f32("iou_predictions", state.iou_predictions);
+        //print_t_f32("low_res_masks", state.low_res_masks);
+        ggml_gallocr_free(state.allocr);
+        state.allocr = NULL;
+    }
+
+    if (!sam_write_masks(model.hparams, img0.nx, img0.ny, state, params.fname_out, params.multimask_output)) {
+        fprintf(stderr, "%s: failed to write masks\n", __func__);
+        return 1;
+    }
+
+    // report timing
+    {
+        const int64_t t_main_end_us = ggml_time_us();
+
+        fprintf(stderr, "\n\n");
+        fprintf(stderr, "%s:     load time = %8.2f ms\n", __func__, t_load_us/1000.0f);
+        fprintf(stderr, "%s:    total time = %8.2f ms\n", __func__, (t_main_end_us - t_main_start_us)/1000.0f);
+    }
+
+    ggml_free(model.ctx);
+
+    return 0;
+}