78 transformer blocks › 75 MoE blocks › Sparse latent attention
Causal mask
×supplied · no parametersattention_mask
Current and earlier key positions for every query.
- shape
- [T queries, T keys]
Sources
Contextual evidence from Construct causal mask
The model embeds tokens, numbers positions from the cached length, always builds the causal mask (the indexer needs it), applies the 78 blocks, normalizes and projects to vocabulary logits with an untied lm_head without upcasting them. The checkpoint’s layer 78, the multi-token-prediction layer, is ignored on load.
transformer · huggingface/transformers / modeling_glm_moe_dsa.py
Pinned revision 5e4d6304de55 ↗ · lines 648–802
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_keys_to_ignore_on_load_unexpected = [r"model\.layers\.78.*"]… lines 649–695 omitted …
if inputs_embeds is None:
inputs_embeds: torch.Tensor = self.embed_tokens(input_ids)
if use_cache and past_key_values is None:
past_key_values = DynamicCache(config=self.config)
if position_ids is None:
past_seen_tokens = past_key_values.get_seq_length() if past_key_values is not None else 0
position_ids = torch.arange(inputs_embeds.shape[1], device=inputs_embeds.device) + past_seen_tokens
position_ids = position_ids.unsqueeze(0)
# It may already have been prepared by e.g. `generate`
if not isinstance(causal_mask_mapping := attention_mask, dict):
mask_kwargs = {
"config": self.config,
"inputs_embeds": inputs_embeds,
"attention_mask": attention_mask,
"past_key_values": past_key_values,
"position_ids": position_ids,
"allow_is_causal_skip": False, # Always force creation to account for causality in the indexer
}
causal_mask_mapping = {"indexed_attention": create_causal_mask(**mask_kwargs)}
hidden_states = inputs_embeds
position_embeddings = self.rotary_emb(hidden_states, position_ids=position_ids)
topk_indices = None # MAIN DIFF with DSV3.2
for i, decoder_layer in enumerate(self.layers[: self.config.num_hidden_layers]):
hidden_states, topk_indices = decoder_layer(
hidden_states,
attention_mask=causal_mask_mapping["indexed_attention"],
position_embeddings=position_embeddings,
position_ids=position_ids,
past_key_values=past_key_values,
use_cache=use_cache,
prev_topk_indices=topk_indices, # MAIN DIFF with DSV3.2
**kwargs,
)
hidden_states = self.norm(hidden_states)
return BaseModelOutputWithPast(
last_hidden_state=hidden_states,
past_key_values=past_key_values,
)… lines 740–748 omitted …
def __init__(self, config):
super().__init__(config)
self.model = GlmMoeDsaModel(config)
self.vocab_size = config.vocab_size
self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)… lines 754–798 omitted …
hidden_states = outputs.last_hidden_state
# Only compute necessary logits, and do not upcast them to float if we are not computing the loss
slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
logits = self.lm_head(hidden_states[:, slice_indices, :])Contextual evidence from Lightning indexer
The indexer owns a query projection from the query latent (32 heads × 128 features), one key projection from the block input followed by LayerNorm, and a head-weight projection; its score scale is 1/√128; the head-weight projection is kept in float32 when loading.
indexer-init · huggingface/transformers / modeling_glm_moe_dsa.py
Pinned revision 5e4d6304de55 ↗ · lines 177–649
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def __init__(self, config: "GlmMoeDsaConfig", layer_idx: int):
super().__init__()
self.config = config
self.layer_idx = layer_idx
self.hidden_size: int = config.hidden_size
self.n_heads: int = config.index_n_heads
self.head_dim: int = config.index_head_dim
self.qk_rope_head_dim: int = config.qk_rope_head_dim
self.index_topk: int = config.index_topk
self.q_lora_rank: int = config.q_lora_rank
self.wq_b = nn.Linear(self.q_lora_rank, self.n_heads * self.head_dim, bias=False)
self.wk = nn.Linear(self.hidden_size, self.head_dim, bias=False)
self.k_norm = nn.LayerNorm(self.head_dim, eps=1e-6)
self.weights_proj = nn.Linear(self.hidden_size, self.n_heads, bias=False)
self.softmax_scale = self.head_dim**-0.5… lines 194–648 omitted …
_keep_in_fp32_modules = ["indexer.weights_proj"]Contextual evidence from Lightning indexer
Indexer queries and the shared key rotate their first 64 features with interleaved RoPE; scores are the ReLU of scaled query–key products in float32, weighted per head by the head weights divided by √32 and summed; the causal mask is added and the top 2,048 positions are kept. There is no Hadamard transform, and it runs without gradients.
indexer-forward · huggingface/transformers / modeling_glm_moe_dsa.py
Pinned revision 5e4d6304de55 ↗ · lines 195–253
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@torch.no_grad()
def forward(
self,
hidden_states: torch.Tensor,
q_resid: torch.Tensor,
position_embeddings: tuple[torch.Tensor, torch.Tensor],
attention_mask: torch.Tensor,
position_ids: torch.Tensor, # Kept for BC
past_key_values: Cache | None = None,
) -> torch.Tensor:
"""
Selects the top-k tokens per query for DeepSeek Sparse Attention (DSA).
Same as [`DeepseekV32Indexer.forward`], but the indexer applies **interleaved** RoPE
rather than the non-interleaved half-split RoPE used by DeepSeek-V3.2.
Args:
hidden_states: Input hidden states `[B, S, hidden_size]`.
q_resid: Query residual from `q_a_layernorm(q_a_proj(x))`, shape `[B, S, q_lora_rank]`.
position_embeddings: `(cos, sin)` from RotaryEmbedding.
attention_mask: Causal mask, broadcastable to `[B, S, T]`.
past_key_values: Cache object containing the indexer key cache for this layer.
Returns:
`torch.Tensor`: the `int32` top-k token indices of shape `[B, S, topk]`. The eager / SDPA paths
turn these into an additive sparse mask; the `flash-mla` kernel consumes them directly.
"""
batch_size, seq_len, _ = hidden_states.shape
cos, sin = position_embeddings
q = self.wq_b(q_resid) # [B, S, H*D]
q = q.view(batch_size, seq_len, self.n_heads, self.head_dim) # [B, S, H, D]
q_rot, q_pass = torch.split(q, [self.qk_rope_head_dim, self.head_dim - self.qk_rope_head_dim], dim=-1)
k = self.k_norm(self.wk(hidden_states)).unsqueeze(2) # [B, S, 1, D]
k_rot, k_pass = torch.split(k, [self.qk_rope_head_dim, self.head_dim - self.qk_rope_head_dim], dim=-1)
# GLM-MoE-DSA uses interleaved RoPE in the indexer
q_rot, k_rot = apply_rotary_pos_emb_interleave(q_rot, k_rot, cos, sin, unsqueeze_dim=2)
q = torch.cat([q_rot, q_pass], dim=-1) # [B, S, H, D]
k = torch.cat([k_rot, k_pass], dim=-1).squeeze(2) # [B, S, D]
if past_key_values is not None:
k = past_key_values.update_indexer(k, self.layer_idx)
scores = torch.matmul(q.float(), k.transpose(-1, -2).float().unsqueeze(1)) * self.softmax_scale
scores = F.relu(scores)
# Weight per head and sum across heads: [B, S, 1, H] @ [B, S, H, T] → [B, S, T]
weights = self.weights_proj(hidden_states.to(self.weights_proj.weight.dtype)).float() * (self.n_heads**-0.5)
index_scores = torch.matmul(weights.unsqueeze(-2), scores).squeeze(-2)
# Causality needs to be taken into account when computing scores so padding tokens don't affect computation
if attention_mask.dtype == torch.bool:
index_scores = index_scores.masked_fill(~attention_mask, float("-inf"))
else:
index_scores = index_scores + attention_mask
topk = min(self.index_topk, index_scores.shape[-1])
return index_scores.topk(topk, dim=-1).indices.to(torch.int32) # [B, S, topk]Contextual evidence from Lightning indexer
The index score is computed in float32, as the head-weighted sum of ReLU(q·k/√128) with the head weights divided by √32; no FP8 kernel is involved.
index-kernel · huggingface/transformers / modeling_glm_moe_dsa.py
Pinned revision 5e4d6304de55 ↗ · lines 239–244
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scores = torch.matmul(q.float(), k.transpose(-1, -2).float().unsqueeze(1)) * self.softmax_scale
scores = F.relu(scores)
# Weight per head and sum across heads: [B, S, 1, H] @ [B, S, H, T] → [B, S, T]
weights = self.weights_proj(hidden_states.to(self.weights_proj.weight.dtype)).float() * (self.n_heads**-0.5)
index_scores = torch.matmul(weights.unsqueeze(-2), scores).squeeze(-2)