llama.cpp/src/models/nemotron-h.cpp

#include "models.h"

void llama_model_nemotron_h::load_arch_hparams(llama_model_loader & ml) {
    ml.get_key(LLM_KV_SSM_CONV_KERNEL,    hparams.ssm_d_conv);
    ml.get_key(LLM_KV_SSM_INNER_SIZE,     hparams.ssm_d_inner);
    ml.get_key(LLM_KV_SSM_STATE_SIZE,     hparams.ssm_d_state);
    ml.get_key(LLM_KV_SSM_TIME_STEP_RANK, hparams.ssm_dt_rank);
    ml.get_key(LLM_KV_SSM_GROUP_COUNT,    hparams.ssm_n_group);

    // A layer is recurrent IFF the n_head_kv value is set to 0 and
    // the n_ff value is set to 0
    for (uint32_t i = 0; i < hparams.n_layer(); ++i) {
        hparams.is_recr_impl[i] = (hparams.n_head_kv(i) == 0 && hparams.n_ff(i) == 0);
    }

    ml.get_key(LLM_KV_ATTENTION_LAYERNORM_RMS_EPS, hparams.f_norm_rms_eps);

    ml.get_key(LLM_KV_EXPERT_FEED_FORWARD_LENGTH,        hparams.n_ff_exp,        false);
    ml.get_key(LLM_KV_EXPERT_SHARED_FEED_FORWARD_LENGTH, hparams.n_ff_shexp,      false);
    ml.get_key(LLM_KV_EXPERT_SHARED_COUNT,               hparams.n_expert_shared, false);
    ml.get_key(LLM_KV_EXPERT_WEIGHTS_NORM,               hparams.expert_weights_norm, false);
    ml.get_key(LLM_KV_EXPERT_WEIGHTS_SCALE,              hparams.expert_weights_scale, false);
    ml.get_key(LLM_KV_MOE_LATENT_SIZE,                   hparams.moe_latent_size, false);

    switch (hparams.n_layer()) {
        case 52: type = LLM_TYPE_31B_A3_5B; break; // Nemotron-H_MOE 31B
        case 56: type = LLM_TYPE_9B; break;
        case 88: type = LLM_TYPE_120B_A12B; break;
        default: type = LLM_TYPE_UNKNOWN;
    }
}

void llama_model_nemotron_h::load_arch_tensors(llama_model_loader &) {
    LLAMA_LOAD_LOCALS;

    // mamba2 Mixer SSM params
    // NOTE: int64_t for tensor dimensions
    const int64_t d_conv     = hparams.ssm_d_conv;
    const int64_t d_inner    = hparams.ssm_d_inner;
    const int64_t d_state    = hparams.ssm_d_state;
    const int64_t n_ssm_head = hparams.ssm_dt_rank;
    const int64_t n_group    = hparams.ssm_n_group;
    const int64_t d_in_proj  = 2*d_inner + 2*n_group*d_state + n_ssm_head;
    const int64_t moe_n_embd = hparams.moe_latent_size > 0 ? hparams.moe_latent_size : n_embd;

    // embeddings
    tok_embd = create_tensor(tn(LLM_TENSOR_TOKEN_EMBD, "weight"), {n_embd, n_vocab}, 0);

    // output
    {
        output_norm = create_tensor(tn(LLM_TENSOR_OUTPUT_NORM, "weight"), {n_embd}, 0);
        output = create_tensor(tn(LLM_TENSOR_OUTPUT, "weight"), {n_embd, n_vocab}, TENSOR_NOT_REQUIRED);
        // if output is NULL, init from the input tok embed, duplicated to allow offloading
        if (output == NULL) {
            output = create_tensor(tn(LLM_TENSOR_TOKEN_EMBD, "weight"), {n_embd, n_vocab}, TENSOR_DUPLICATED);
        }
    }

    for (int i = 0; i < n_layer; ++i) {
        auto & layer = layers[i];

        // all blocks use the attn norm
        layer.attn_norm  = create_tensor(tn(LLM_TENSOR_ATTN_NORM, "weight", i), {n_embd}, 0);

        if (hparams.is_recr(i)) {
            // ssm layers
            layer.ssm_in = create_tensor(tn(LLM_TENSOR_SSM_IN, "weight", i), {n_embd, d_in_proj}, 0);

            layer.ssm_conv1d = create_tensor(tn(LLM_TENSOR_SSM_CONV1D, "weight", i), {d_conv, d_inner + 2*n_group*d_state}, 0);
            layer.ssm_conv1d_b = create_tensor(tn(LLM_TENSOR_SSM_CONV1D, "bias", i), {d_inner + 2*n_group*d_state}, TENSOR_NOT_REQUIRED);

            layer.ssm_dt_b = create_tensor(tn(LLM_TENSOR_SSM_DT, "bias", i), {n_ssm_head}, 0);

            // no "weight" suffix for these
            layer.ssm_a = create_tensor(tn(LLM_TENSOR_SSM_A, i), {1, n_ssm_head}, 0);
            layer.ssm_d = create_tensor(tn(LLM_TENSOR_SSM_D, i), {1, n_ssm_head}, 0);

            layer.ssm_norm = create_tensor(tn(LLM_TENSOR_SSM_NORM, "weight", i), {d_inner / n_group, n_group}, 0);

            // out_proj
            layer.ssm_out = create_tensor(tn(LLM_TENSOR_SSM_OUT, "weight", i), {d_inner, n_embd}, 0);
        } else if (hparams.n_ff(i) == 0) {
            // attention layers (with optional bias)
            const int64_t n_head_i = hparams.n_head(i);
            const int64_t n_embd_k_gqa_i = hparams.n_embd_k_gqa(i);
            const int64_t n_embd_v_gqa_i = hparams.n_embd_v_gqa(i);
            create_tensor_qkv(layer, i, n_embd, n_embd_head_k * n_head_i, n_embd_k_gqa_i, n_embd_v_gqa_i, 0);
            layer.wo = create_tensor(tn(LLM_TENSOR_ATTN_OUT, "weight", i), {n_embd_head_k * n_head_i, n_embd}, 0);
            layer.wo_b = create_tensor(tn(LLM_TENSOR_ATTN_OUT, "bias", i), {n_embd}, TENSOR_NOT_REQUIRED);
        }  else {
            if (n_expert != 0) {
                const int64_t n_ff_exp = hparams.n_ff_exp ? hparams.n_ff_exp : n_ff / n_expert_used;
                const int64_t n_ff_shexp = hparams.n_ff_shexp;

                layer.ffn_gate_inp    = create_tensor(tn(LLM_TENSOR_FFN_GATE_INP,  "weight", i), { n_embd, n_expert}, 0);
                layer.ffn_exp_probs_b = create_tensor(tn(LLM_TENSOR_FFN_EXP_PROBS_B, "bias", i), {n_expert         }, 0);

                // MoE branch
                layer.ffn_latent_down = create_tensor(tn(LLM_TENSOR_FFN_LATENT_DOWN, "weight", i), {n_embd, moe_n_embd}, TENSOR_NOT_REQUIRED);
                layer.ffn_latent_up   = create_tensor(tn(LLM_TENSOR_FFN_LATENT_UP,   "weight", i), {moe_n_embd, n_embd}, TENSOR_NOT_REQUIRED);

                layer.ffn_down_exps   = create_tensor(tn(LLM_TENSOR_FFN_DOWN_EXPS, "weight", i), {n_ff_exp,   moe_n_embd, n_expert}, 0);
                layer.ffn_up_exps     = create_tensor(tn(LLM_TENSOR_FFN_UP_EXPS,   "weight", i), {moe_n_embd, n_ff_exp, n_expert}, 0);

                // Shared expert branch
                layer.ffn_down_shexp  = create_tensor(tn(LLM_TENSOR_FFN_DOWN_SHEXP, "weight", i), {n_ff_shexp, n_embd}, 0);
                layer.ffn_up_shexp    = create_tensor(tn(LLM_TENSOR_FFN_UP_SHEXP,   "weight", i), {n_embd, n_ff_shexp}, 0);

            } else {
                // mlp layers
                layer.ffn_down   = create_tensor(tn(LLM_TENSOR_FFN_DOWN, "weight", i), {  hparams.n_ff(i), n_embd}, 0);
                layer.ffn_up     = create_tensor(tn(LLM_TENSOR_FFN_UP,   "weight", i), {n_embd,   hparams.n_ff(i)}, 0);
                layer.ffn_down_b = create_tensor(tn(LLM_TENSOR_FFN_DOWN, "bias",   i), {n_embd}, TENSOR_NOT_REQUIRED);
                layer.ffn_up_b   = create_tensor(tn(LLM_TENSOR_FFN_UP,   "bias",   i), {hparams.n_ff(i)}, TENSOR_NOT_REQUIRED);
            }
        }
    }
}

std::unique_ptr<llm_graph_context> llama_model_nemotron_h::build_arch_graph(const llm_graph_params & params) const {
    return std::make_unique<graph>(*this, params);
}

llama_model_nemotron_h::graph::graph(const llama_model & model, const llm_graph_params & params) :
    llm_build_mamba_base(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);
    ggml_build_forward_expand(gf, inpL);

    auto * inp = build_inp_mem_hybrid();

    ggml_tensor * inp_out_ids = build_inp_out_ids();

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

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

        if (hparams.is_recr(il)) {
            // ssm layer //
            cur = build_mamba2_layer(inp->get_recr(), cur, model, ubatch, il);
        } else if (hparams.n_ff(il) == 0) {
            // attention layer //
            cur = build_attention_layer(cur, inp->get_attn(), model, n_embd_head, il);
        } else {
            cur = build_ffn_layer(cur, model, 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);
        }

        // add residual
        cur = ggml_add(ctx0, cur, inpSA);
        cb(cur, "nemotron_h_block_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
    cur = build_lora_mm(model.output, cur, model.output_s);
    cb(cur, "result_output", -1);
    res->t_logits = cur;

    ggml_build_forward_expand(gf, cur);
}

ggml_tensor * llama_model_nemotron_h::graph::build_attention_layer(ggml_tensor *             cur,
                                                          llm_graph_input_attn_kv * inp_attn,
                                                          const llama_model &       model,
                                                                int64_t             n_embd_head,
                                                                int                 il) {
    auto [Qcur, Kcur, Vcur] = build_qkv(model.layers[il], cur, n_embd_head, hparams.n_head(il), hparams.n_head_kv(il), il);

    const float kq_scale =
        hparams.f_attention_scale == 0.0f ? 1.0f / sqrtf(float(n_embd_head)) : hparams.f_attention_scale;
    cur = build_attn(inp_attn,
            model.layers[il].wo, model.layers[il].wo_b, model.layers[il].wo_s,
            Qcur, Kcur, Vcur, nullptr, nullptr, nullptr, kq_scale, il);
    cb(cur, "attn_out", il);
    return cur;
}

ggml_tensor * llama_model_nemotron_h::graph::build_ffn_layer(ggml_tensor * cur, const llama_model & model, int il) {
    if (model.layers[il].ffn_gate_inp == nullptr) {
        cur = build_ffn(cur,
                model.layers[il].ffn_up,   model.layers[il].ffn_up_b,   model.layers[il].ffn_up_s,
                NULL,                      NULL,                        NULL,
                model.layers[il].ffn_down, model.layers[il].ffn_down_b, model.layers[il].ffn_down_s,
                NULL,
                LLM_FFN_RELU_SQR, LLM_FFN_PAR, il);
        cb(cur, "ffn_out", il);
    } else {
        ggml_tensor * inp_emb    = cur;
        ggml_tensor * inp_latent = cur;

        if (model.layers[il].ffn_latent_down) {
            inp_latent = ggml_mul_mat(ctx0, model.layers[il].ffn_latent_down, cur);
        }

        ggml_tensor * router_logits = build_lora_mm(model.layers[il].ffn_gate_inp, cur);
        cb(router_logits, "ffn_moe_logits", il);

        ggml_tensor * moe_out =
            build_moe_ffn(inp_latent,
                    model.layers[il].ffn_gate_inp,
                    model.layers[il].ffn_up_exps,
                    nullptr, // no gate
                    model.layers[il].ffn_down_exps,
                    model.layers[il].ffn_exp_probs_b,
                    n_expert, n_expert_used,
                    LLM_FFN_RELU_SQR, hparams.expert_weights_norm,
                    hparams.expert_weights_scale,
                    LLAMA_EXPERT_GATING_FUNC_TYPE_SIGMOID,
                    il,
                    router_logits, nullptr,
                    model.layers[il].ffn_up_exps_s,
                    nullptr, // no gate
                    model.layers[il].ffn_down_exps_s);
        cb(moe_out, "ffn_moe_out", il);

        if (model.layers[il].ffn_latent_up) {
            moe_out = ggml_mul_mat(ctx0, model.layers[il].ffn_latent_up, moe_out);
        }

        ggml_tensor * ffn_shexp = build_ffn(inp_emb,
                    model.layers[il].ffn_up_shexp,   NULL, model.layers[il].ffn_up_shexp_s,
                    NULL /* no gate */           ,   NULL, NULL,
                    model.layers[il].ffn_down_shexp, NULL, model.layers[il].ffn_down_shexp_s,
                    NULL,
                    LLM_FFN_RELU_SQR, LLM_FFN_PAR, il);
        cb(ffn_shexp, "ffn_shexp", il);

        cur = ggml_add(ctx0, moe_out, ffn_shexp);
        cb(cur, "ffn_out", il);
    }

    cur = build_cvec(cur, il);
    cb(cur, "l_out", il);

    return cur;
}