src/models/bitnet.cpp

#include "models.h"


llm_build_bitnet::llm_build_bitnet(const llama_model & model, const llm_graph_params & params) : llm_graph_context(params) {
    const int64_t n_embd_head = hparams.n_embd_head_v;

    GGML_ASSERT(n_embd_head == hparams.n_embd_head_k);

    ggml_tensor * cur;
    ggml_tensor * inpL;

    inpL = build_inp_embd(model.tok_embd);

    // inp_pos - contains the positions
    ggml_tensor * inp_pos = build_inp_pos();

    auto * inp_attn = build_attn_inp_kv();

    ggml_tensor * inp_out_ids = build_inp_out_ids();

    for (int il = 0; il < n_layer; ++il) {
        ggml_tensor * inpSA = inpL;

        cur = build_norm(inpL,
                model.layers[il].attn_norm, NULL,
                LLM_NORM_RMS, il);
        cb(cur, "attn_norm", il);

        // self-attention
        {
            // compute Q and K and RoPE them
            ggml_tensor * Qcur = build_lora_mm(model.layers[il].wq, cur);
            if (model.layers[il].wq_scale) {
                Qcur = ggml_mul(ctx0, Qcur, model.layers[il].wq_scale);
            }
            cb(Qcur, "Qcur", il);
            if (model.layers[il].bq) {
                Qcur = ggml_add(ctx0, Qcur, model.layers[il].bq);
                cb(Qcur, "Qcur", il);
            }

            // B1.K
            ggml_tensor * Kcur = build_lora_mm(model.layers[il].wk, cur);
            if (model.layers[il].wk_scale) {
                Kcur = ggml_mul(ctx0, Kcur, model.layers[il].wk_scale);
            }
            cb(Kcur, "Kcur", il);
            if (model.layers[il].bk) {
                Kcur = ggml_add(ctx0, Kcur, model.layers[il].bk);
                cb(Kcur, "Kcur", il);
            }

            // B1.V
            ggml_tensor * Vcur = build_lora_mm(model.layers[il].wv, cur);
            if (model.layers[il].wv_scale) {
                Vcur = ggml_mul(ctx0, Vcur, model.layers[il].wv_scale);
            }
            cb(Vcur, "Vcur", il);
            if (model.layers[il].bv) {
                Vcur = ggml_add(ctx0, Vcur, model.layers[il].bv);
                cb(Vcur, "Vcur", il);
            }

            Qcur = ggml_reshape_3d(ctx0, Qcur, n_embd_head, n_head,    n_tokens);
            Kcur = ggml_reshape_3d(ctx0, Kcur, n_embd_head, n_head_kv, n_tokens);
            Vcur = ggml_reshape_3d(ctx0, Vcur, n_embd_head, n_head_kv, n_tokens);

            Qcur = ggml_rope_ext(
                    ctx0, Qcur, inp_pos, nullptr,
                    n_rot, rope_type, n_ctx_orig, freq_base, freq_scale,
                    ext_factor, attn_factor, beta_fast, beta_slow
                    );

            Kcur = ggml_rope_ext(
                    ctx0, Kcur, inp_pos, nullptr,
                    n_rot, rope_type, n_ctx_orig, freq_base, freq_scale,
                    ext_factor, attn_factor, beta_fast, beta_slow
                    );

            cb(Qcur, "Qcur", il);
            cb(Kcur, "Kcur", il);
            cb(Vcur, "Vcur", il);

            cur = build_attn(inp_attn,
                    NULL, NULL,
                    Qcur, Kcur, Vcur, nullptr, nullptr, nullptr, 1.0f/sqrtf(float(n_embd_head)), il);

            cur = build_norm(cur,
                    model.layers[il].attn_sub_norm, NULL,
                    LLM_NORM_RMS, il);
            cb(cur, "attn_sub_norm", il);

            cur = build_lora_mm(model.layers[il].wo, cur);
            if (model.layers[il].wo_scale) {
                cur = ggml_mul(ctx0, cur, model.layers[il].wo_scale);
            }
            if (model.layers[il].bo) {
                cur = ggml_add(ctx0, cur, model.layers[il].bo);
            }
            cb(cur, "attn_out", il);
        }

        if (il == n_layer - 1 && inp_out_ids) {
            cur   = ggml_get_rows(ctx0,   cur, inp_out_ids);
            inpSA = ggml_get_rows(ctx0, inpSA, inp_out_ids);
        }

        ggml_tensor * ffn_inp = ggml_add(ctx0, cur, inpSA);
        cb(ffn_inp, "ffn_inp", il);

        // feed-forward forward
        cur = build_norm(ffn_inp,
                model.layers[il].ffn_norm, NULL,
                LLM_NORM_RMS, il);
        cb(cur, "ffn_norm", il);

        cur = build_ffn(cur,
                model.layers[il].ffn_up,   NULL, model.layers[il].ffn_up_scale,
                model.layers[il].ffn_gate, NULL, model.layers[il].ffn_gate_scale,
                NULL,                      NULL, NULL,
                NULL,
                LLM_FFN_SILU, LLM_FFN_PAR, il);
        cb(cur, "ffn_sub_out", il);

        cur = build_norm(cur,
                model.layers[il].ffn_sub_norm, NULL,
                LLM_NORM_RMS, il);
        cb(cur, "ffn_sub_norm", il);

        cur = build_lora_mm(model.layers[il].ffn_down, cur);
        if (model.layers[il].ffn_down_scale) {
            cur = ggml_mul(ctx0, cur, model.layers[il].ffn_down_scale);
        }
        cb(cur, "ffn_down", il);

        cur = ggml_add(ctx0, cur, ffn_inp);
        cb(cur, "l_out", il);

        // input for next layer
        inpL = cur;
    }

    cur = inpL;

    cur = build_norm(cur,
            model.output_norm, NULL,
            LLM_NORM_RMS, -1);

    cb(cur, "result_norm", -1);
    res->t_embd = cur;

    // lm_head
    // FIXME: do not use model.tok_embd directly, duplicate as model.output
    cur = build_lora_mm(model.tok_embd, cur);

    cb(cur, "result_output", -1);
    res->t_logits = cur;

    ggml_build_forward_expand(gf, cur);
}