61 transformer blocks › 58 MoE blocks › Mixture of experts
Input features
×tensorx · 780
The normalized features entering the MoE layer.
- shape
- [B batch, T positions, 7168 d]
Sources
Contextual evidence from MoE 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 MoE 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 Router
The router owns one score vector per routed expert and, at this width, a per-expert bias used only for selection.
gate-init · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 668–675
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self.dim = args.dim
self.topk = args.n_activated_experts
self.n_groups = args.n_expert_groups
self.topk_groups = args.n_limited_groups
self.score_func = args.score_func
self.route_scale = args.route_scale
self.weight = nn.Parameter(torch.empty(args.n_routed_experts, args.dim))
self.bias = nn.Parameter(torch.empty(args.n_routed_experts, dtype=torch.float32)) if self.dim == 7168 else NoneContextual evidence from Router
Routing: sigmoid scores, bias added for selection, the best groups kept by their top-two scores, the top-8 experts chosen, their unbiased scores renormalized and scaled.
gate-forward · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 687–709
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scores = linear(x.float(), self.weight.float())
if self.score_func == "softmax":
scores = scores.softmax(dim=-1)
else:
scores = scores.sigmoid()
original_scores = scores
if self.bias is not None:
scores = scores + self.bias
if self.n_groups > 1:
scores = scores.view(x.size(0), self.n_groups, -1)
if self.bias is None:
group_scores = scores.amax(dim=-1)
else:
group_scores = scores.topk(2, dim=-1)[0].sum(dim=-1)
indices = group_scores.topk(self.topk_groups, dim=-1)[1]
mask = scores.new_ones(x.size(0), self.n_groups, dtype=bool).scatter_(1, indices, False)
scores = scores.masked_fill_(mask.unsqueeze(-1), float("-inf")).flatten(1)
indices = scores.topk(self.topk, dim=-1)[1]
weights = original_scores.gather(1, indices)
if self.score_func == "sigmoid":
weights /= weights.sum(dim=-1, keepdim=True)
weights *= self.route_scale
return weights, indicesContextual evidence from Routed expert
Each routed expert is its own SwiGLU MLP of moe_inter_dim hidden features.
expert · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 730–744
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self.w1 = Linear(dim, inter_dim)
self.w2 = Linear(inter_dim, dim)
self.w3 = Linear(dim, inter_dim)… lines 733–743 omitted …
return self.w2((F.silu(self.w1(x).float()) * self.w3(x).float()).type_as(x))Contextual evidence from Routed expert
The MoE layer holds the router, the routed experts and one shared expert MLP of n_shared_experts × moe_inter_dim features.
moe-init · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 770–778
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self.n_routed_experts = args.n_routed_experts
self.n_local_experts = args.n_routed_experts // world_size
self.n_activated_experts = args.n_activated_experts
self.experts_start_idx = rank * self.n_local_experts
self.experts_end_idx = self.experts_start_idx + self.n_local_experts
self.gate = Gate(args)
self.experts = nn.ModuleList([Expert(args.dim, args.moe_inter_dim) if self.experts_start_idx <= i < self.experts_end_idx else None
for i in range(self.n_routed_experts)])
self.shared_experts = MLP(args.dim, args.n_shared_experts * args.moe_inter_dim, reduce_output=False)Contextual evidence from Routed expert
Each token’s output is the router-weighted sum of its selected experts plus the shared expert applied to every token.
moe-forward · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 790–803
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shape = x.size()
x = x.view(-1, self.dim)
weights, indices = self.gate(x)
y = torch.zeros_like(x, dtype=torch.float32)
counts = torch.bincount(indices.flatten(), minlength=self.n_routed_experts).tolist()
for i in range(self.experts_start_idx, self.experts_end_idx):
if counts[i] == 0:
continue
expert = self.experts[i]
idx, top = torch.where(indices == i)
y[idx] += expert(x[idx]) * weights[idx, top, None]
y += self.shared_experts(x)
if world_size > 1:
dist.all_reduce(y)Contextual evidence from Shared expert
The dense feed-forward network is a SwiGLU MLP: w2(silu(w1 x) ⊙ w3 x).
mlp · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 629–643
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self.w1 = ColumnParallelLinear(dim, inter_dim)
self.w2 = RowParallelLinear(inter_dim, dim, reduce_output=reduce_output)
self.w3 = ColumnParallelLinear(dim, inter_dim)… lines 632–642 omitted …
return self.w2((F.silu(self.w1(x).float()) * self.w3(x).float()).type_as(x))