61 transformer blocks › 58 MoE blocks › Sparse latent attention › Lightning indexer › Indexer key
Attention input
×tensorx · 457
The normalized features entering attention.
- shape
- [B batch, T positions, 7168 d]
Sources
Contextual evidence from Attention RMSNorm
RMSNorm owns one gain per feature and computes in float32; with a residual argument it first adds the residual, fusing the residual addition into the next normalization.
rmsnorm · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 280–306
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def __init__(self, dim: int, eps: float = 1e-6):
super().__init__()
self.dim = dim
self.eps = eps
self.weight = nn.Parameter(torch.ones(dim, dtype=torch.float32))
def forward(self, x: torch.Tensor, residual: Optional[torch.Tensor] = None):
"""
Forward pass for RMSNorm.
Args:
x (torch.Tensor): Input tensor.
Returns:
torch.Tensor: Normalized tensor with the same shape as input.
"""
dtype = x.dtype
if residual is None:
x = x.float()
var = x.pow(2).mean(-1, keepdim=True)
x = x * torch.rsqrt(var + self.eps)
return (self.weight * x).to(dtype)
else:
x = residual = x.float() + residual.float()
var = x.pow(2).mean(-1, keepdim=True)
x = x * torch.rsqrt(var + self.eps)
return (self.weight * x).to(dtype), residual.to(dtype)Contextual evidence from Attention RMSNorm
A block applies attention-norm, MLA, ffn-norm and the FFN; the first n_dense_layers blocks use the dense MLP, the rest MoE. Residual additions happen inside the next normalization.
block · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 826–851
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self.attn = MLA(args)
self.ffn = MLP(args.dim, args.inter_dim) if layer_id < args.n_dense_layers else MoE(args)
self.attn_norm = RMSNorm(args.dim)
self.ffn_norm = RMSNorm(args.dim)… lines 830–843 omitted …
if residual is None:
x, residual = self.attn_norm(x), x
else:
x, residual = self.attn_norm(x, residual)
x = self.attn(x, start_pos, freqs_cis, mask)
x, residual = self.ffn_norm(x, residual)
x = self.ffn(x)
return x, residualContextual evidence from Indexer key
The lightning indexer owns a query up-projection from the query latent, a single key projection with LayerNorm, and a per-head weight projection.
indexer-init · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 436–452
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def __init__(self, args: ModelArgs):
super().__init__()
self.dim: int = args.dim
self.n_heads: int = args.index_n_heads
self.n_local_heads = args.index_n_heads // world_size
self.head_dim: int = args.index_head_dim
self.rope_head_dim: int = args.qk_rope_head_dim
self.index_topk: int = args.index_topk
self.q_lora_rank: int = args.q_lora_rank
self.wq_b = Linear(self.q_lora_rank, self.n_heads * self.head_dim)
self.wk = Linear(self.dim, self.head_dim)
self.k_norm = LayerNorm(self.head_dim)
# weights_proj in the checkpoint is stored in bf16, while the parameters here are stored in fp32 for convenient.
self.weights_proj = Linear(self.dim, self.n_heads, dtype=torch.float32)
self.softmax_scale = self.head_dim ** -0.5
self.scale_fmt = args.scale_fmt
Contextual evidence from Indexer key
Indexer scores combine per-head query–key products with learned per-head weights, add the causal mask and keep the top-k positions for each query.
indexer-forward · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 457–487
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def forward(self, x: torch.Tensor, qr: torch.Tensor, start_pos: int, freqs_cis: torch.Tensor, mask: Optional[torch.Tensor]):
bsz, seqlen, _ = x.size()
end_pos = start_pos + seqlen
q = self.wq_b(qr)
q = q.view(bsz, seqlen, self.n_heads, self.head_dim)
q_pe, q_nope = torch.split(q, [self.rope_head_dim, self.head_dim - self.rope_head_dim], dim=-1)
# rope in indexer is not interleaved
q_pe = apply_rotary_emb(q_pe, freqs_cis, False)
q = torch.cat([q_pe, q_nope], dim=-1)
k = self.wk(x)
k = self.k_norm(k)
k_pe, k_nope = torch.split(k, [self.rope_head_dim, self.head_dim - self.rope_head_dim], dim=-1)
# rope in indexer is not interleaved
k_pe = apply_rotary_emb(k_pe.unsqueeze(2), freqs_cis, False).squeeze(2)
k = torch.cat([k_pe, k_nope], dim=-1)
q = rotate_activation(q)
k = rotate_activation(k)
q_fp8, q_scale = act_quant(q, block_size, self.scale_fmt)
k_fp8, k_scale = act_quant(k, block_size, self.scale_fmt)
self.k_cache[:bsz, start_pos:end_pos] = k_fp8
self.k_scale_cache[:bsz, start_pos:end_pos] = k_scale
weights = self.weights_proj(x.float()) * self.n_heads ** -0.5
weights = weights.unsqueeze(-1) * q_scale * self.softmax_scale
index_score = fp8_index(q_fp8.contiguous(), weights, self.k_cache[:bsz, :end_pos].contiguous(), self.k_scale_cache[:bsz, :end_pos].contiguous())
if mask is not None:
index_score += mask
topk_indices = index_score.topk(min(self.index_topk, end_pos), dim=-1)[1]
topk_indices_ = topk_indices.clone()
dist.broadcast(topk_indices_, src=0)
assert torch.all(topk_indices == topk_indices_), f"{topk_indices=} {topk_indices_=}"
return topk_indices