partially apply to deepseek2

This commit is contained in:
Xuan Son Nguyen
2026-08-21 12:07:53 +02:00
parent 450f03946f
commit d5e61c0331
2 changed files with 27 additions and 19 deletions
+4 -2
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@@ -168,15 +168,17 @@ Examples:
### Rotating only a part of the head
Many models rotate only a part of each head and leave the rest untouched (often called the "nope" part). Do not build this with views plus `ggml_concat`: `ggml_concat` allocates a new tensor and copies every element, which costs more than the RoPE itself. Both layouts can be done with a single RoPE op that copies the untouched dims through for you:
Many models rotate only a part of each head and leave the rest untouched (often called the "nope" part). Do not build this with views plus `ggml_concat`, it's not efficient. Both layouts can be done with a single RoPE op:
- `[rope|nope]`, rotated dims first: pass `n_dims` smaller than the head size to `ggml_rope_ext`. Dims from `n_dims` to the end are copied as-is.
- `[nope|rope]`, rotated dims last: call `ggml_rope_set_offset(cur, n_offs)` on the result of the RoPE, where `n_offs` is the size of the leading untouched part. Dims outside `[n_offs, n_offs + n_dims)` are copied as-is.
`n_offs` must be even, `n_offs + n_dims` must fit in the row, and vision RoPE is not supported. Note that the frequencies are computed relative to the rotated window, so the result matches applying `ggml_rope_ext` to that slice on its own.
`n_offs` must be even, `n_offs + n_dims` must fit in the row, and vision RoPE is not supported. Note that the frequencies are computed relative to the rotated window.
Example: DeepSeek-V4 uses `[nope|rope]` for its query, key and compressed KV tensors, so `src/models/deepseek4.cpp` ropes the whole tensor and then calls `ggml_rope_set_offset(cur, n_embd_head_nope)`.
Exception: some models apply an extra op to the `nope` part, for example `deepseek32.cpp`, and may not use this optimization. While RoPE can be applied selectively to a part of the head, the extra op may not, so these models still need views plus `ggml_concat`.
## GGUF specification
https://github.com/ggml-org/ggml/blob/master/docs/gguf.md
+23 -17
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@@ -524,17 +524,9 @@ llama_model_deepseek2::graph::graph(const llama_model & model, const llm_graph_p
q = ggml_mul_mat(ctx0, model.layers[il].wq, cur);
cb(q, "q", il);
}
// split into {n_embd_head_qk_nope, n_head, n_tokens}
ggml_tensor * q_nope =
ggml_view_3d(ctx0, q, n_embd_head_qk_nope, n_head, n_tokens, ggml_row_size(q->type, n_embd_head_k),
ggml_row_size(q->type, n_embd_head_k) * n_head, 0);
cb(q_nope, "q_nope", il);
// and {n_embd_head_qk_rope, n_head, n_tokens}
ggml_tensor * q_pe = ggml_view_3d(
ctx0, q, n_embd_head_qk_rope, n_head, n_tokens, ggml_row_size(q->type, n_embd_head_k),
ggml_row_size(q->type, n_embd_head_k) * n_head, ggml_row_size(q->type, n_embd_head_qk_nope));
cb(q_pe, "q_pe", il);
// {n_embd_head_k, n_head, n_tokens}
q = ggml_reshape_3d(ctx0, q, n_embd_head_k, n_head, n_tokens);
cb(q, "q", il);
ggml_tensor * kv_cmpr_pe = ggml_mul_mat(ctx0, model.layers[il].wkv_a_mqa, cur);
cb(kv_cmpr_pe, "kv_cmpr_pe", il);
@@ -552,10 +544,6 @@ llama_model_deepseek2::graph::graph(const llama_model & model, const llm_graph_p
ggml_row_size(kv_cmpr_pe->type, kv_lora_rank));
cb(k_pe, "k_pe", il);
q_pe = ggml_rope_ext(ctx0, q_pe, inp_pos, nullptr, n_rot, rope_type, n_ctx_orig, freq_base, freq_scale,
ext_factor, attn_factor, beta_fast, beta_slow);
cb(q_pe, "q_pe", il);
k_pe = ggml_rope_ext(ctx0, k_pe, inp_pos, nullptr, n_rot, rope_type, n_ctx_orig, freq_base, freq_scale,
ext_factor, attn_factor, beta_fast, beta_slow);
cb(k_pe, "k_pe", il);
@@ -564,6 +552,20 @@ llama_model_deepseek2::graph::graph(const llama_model & model, const llm_graph_p
cb(kv_cmpr, "kv_cmpr", il);
if (is_mla) {
// split into {n_embd_head_qk_nope, n_head, n_tokens}
ggml_tensor * q_nope = ggml_view_3d(ctx0, q, n_embd_head_qk_nope, n_head, n_tokens,
q->nb[1], q->nb[2], 0);
cb(q_nope, "q_nope", il);
// and {n_embd_head_qk_rope, n_head, n_tokens}
ggml_tensor * q_pe = ggml_view_3d(ctx0, q, n_embd_head_qk_rope, n_head, n_tokens,
q->nb[1], q->nb[2], ggml_row_size(q->type, n_embd_head_qk_nope));
cb(q_pe, "q_pe", il);
q_pe = ggml_rope_ext(ctx0, q_pe, inp_pos, nullptr, n_rot, rope_type, n_ctx_orig, freq_base, freq_scale,
ext_factor, attn_factor, beta_fast, beta_slow);
cb(q_pe, "q_pe", il);
// {n_embd_head_qk_nope, n_tokens, n_head}
q_nope = ggml_permute(ctx0, q_nope, 0, 2, 1, 3);
cb(q_nope, "q_nope_perm", il);
@@ -623,10 +625,14 @@ llama_model_deepseek2::graph::graph(const llama_model & model, const llm_graph_p
Vcur = ggml_cont(ctx0, Vcur);
cb(Vcur, "Vcur_cont", il);
ggml_tensor * Qcur = ggml_concat(ctx0, q_nope, q_pe, 0);
// RoPE is applied to the trailing dims only
ggml_tensor * Qcur = ggml_rope_ext(ctx0, q, inp_pos, nullptr, n_rot, rope_type, n_ctx_orig,
freq_base, freq_scale, ext_factor, attn_factor, beta_fast, beta_slow);
Qcur = ggml_rope_set_offset(Qcur, n_embd_head_qk_nope);
cb(Qcur, "Qcur", il);
ggml_tensor * Kcur = ggml_concat(ctx0, k_nope, ggml_repeat(ctx0, k_pe, q_pe), 0);
ggml_tensor * Kcur = ggml_concat(ctx0, k_nope,
ggml_repeat_4d(ctx0, k_pe, n_embd_head_qk_rope, n_head, n_tokens, 1), 0);
cb(Kcur, "Kcur", il);
if (inp_attn_scale) {