1#include "models.h"
 2
 3ggml_cgraph * clip_graph_llama4::build() {
 4    GGML_ASSERT(model.class_embedding != nullptr);
 5    GGML_ASSERT(model.position_embeddings != nullptr);
 6
 7    const int n_pos = n_patches + 1; // +1 for [CLS]
 8
 9    // 2D input positions
10    ggml_tensor * pos_h = ggml_new_tensor_1d(ctx0, GGML_TYPE_I32, n_pos);
11    ggml_set_name(pos_h, "pos_h");
12    ggml_set_input(pos_h);
13
14    ggml_tensor * pos_w = ggml_new_tensor_1d(ctx0, GGML_TYPE_I32, n_pos);
15    ggml_set_name(pos_w, "pos_w");
16    ggml_set_input(pos_w);
17
18    ggml_tensor * inp = build_inp_raw();
19
20    // Llama4UnfoldConvolution
21    {
22        ggml_tensor * kernel = ggml_reshape_4d(ctx0, model.patch_embeddings_0,
23                                                patch_size, patch_size, 3, n_embd);
24        inp = ggml_im2col(ctx0, kernel, inp, patch_size, patch_size, 0, 0, 1, 1, true, inp->type);
25        inp = ggml_mul_mat(ctx0, model.patch_embeddings_0, inp);
26        inp = ggml_reshape_2d(ctx0, inp, n_embd, n_patches);
27        cb(inp, "patch_conv", -1);
28    }
29
30    // add CLS token
31    inp = ggml_concat(ctx0, inp, model.class_embedding, 1);
32
33    // build ViT with 2D position embeddings
34    auto add_pos = [&](ggml_tensor * cur, const clip_layer &) {
35        // first half is X axis and second half is Y axis
36        // ref: https://github.com/huggingface/transformers/blob/40a493c7ed4f19f08eadb0639cf26d49bfa5e180/src/transformers/models/llama4/modeling_llama4.py#L1312
37        // ref: https://github.com/Blaizzy/mlx-vlm/blob/a57156aa87b33cca6e5ee6cfc14dd4ef8f611be6/mlx_vlm/models/llama4/vision.py#L441
38        return build_rope_2d(ctx0, cur, pos_w, pos_h, hparams.rope_theta, false);
39    };
40    ggml_tensor * cur = build_vit(
41                            inp, n_pos,
42                            NORM_TYPE_NORMAL,
43                            hparams.ffn_op,
44                            model.position_embeddings,
45                            add_pos);
46
47    // remove CLS token
48    cur = ggml_view_2d(ctx0, cur,
49        n_embd, n_patches,
50        ggml_row_size(cur->type, n_embd), 0);
51
52    // pixel shuffle
53    // based on Llama4VisionPixelShuffleMLP
54    // https://github.com/huggingface/transformers/blob/2932f318a20d9e54cc7aea052e040164d85de7d6/src/transformers/models/llama4/modeling_llama4.py#L1151
55    {
56        const int scale_factor = model.hparams.n_merge;
57        const int bsz = 1; // batch size, always 1 for now since we don't support batching
58        GGML_ASSERT(scale_factor > 0);
59        GGML_ASSERT(n_patches_x == n_patches_y); // llama4 only supports square images
60        cur = ggml_reshape_4d(ctx0, cur,
61            n_embd * scale_factor,
62            n_patches_x / scale_factor,
63            n_patches_y,
64            bsz);
65        cur = ggml_permute(ctx0, cur, 0, 2, 1, 3);
66        cur = ggml_cont_4d(ctx0, cur,
67            n_embd * scale_factor * scale_factor,
68            n_patches_x / scale_factor,
69            n_patches_y / scale_factor,
70            bsz);
71        //cur = ggml_permute(ctx0, cur, 0, 2, 1, 3);
72        // flatten to 2D
73        cur = ggml_cont_2d(ctx0, cur,
74            n_embd * scale_factor * scale_factor,
75            n_patches / scale_factor / scale_factor);
76        cb(cur, "pixel_shuffle", -1);
77    }
78
79    // based on Llama4VisionMLP2 (always uses GELU activation, no bias)
80    {
81        cur = ggml_mul_mat(ctx0, model.mm_model_mlp_1_w, cur);
82        cur = ggml_gelu(ctx0, cur);
83        cur = ggml_mul_mat(ctx0, model.mm_model_mlp_2_w, cur);
84        cur = ggml_gelu(ctx0, cur);
85        cb(cur, "adapter_mlp", -1);
86    }
87
88    // Llama4MultiModalProjector
89    cur = ggml_mul_mat(ctx0, model.mm_model_proj, cur);
90    cb(cur, "projected", -1);
91
92    // build the graph
93    ggml_build_forward_expand(gf, cur);
94
95    return gf;
96}