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7 Commits
617c0f1d47 ... 207db58dbc

Author SHA1 Message Date
王翛玄 207db58dbc
Merge 0761ffa7cd into cc312c1cc6 2026-09-19 09:03:44 +08:00
jingyaogong cc312c1cc6 [fix] unify Ctrl+C handling 2026-09-18 16:33:09 +08:00
jingyaogong e2ee878519
Merge pull request #857 from wbbeyourself/fix-ctrl-c-exception 
fix: eval_llm.py Ctrl+C 退出异常修复
 2026-09-18 15:54:43 +08:00
jingyaogong b63a9565e3 [fix] restore top-1 router gradient #858 2026-09-18 15:28:50 +08:00
jingyaogong 1aae25911b
Merge pull request #859 from basil-k-aji-dev/fix/moe-router-gradient-topk1 
[fix] keep the MoE router trainable at num_experts_per_tok=1
 2026-09-18 15:03:36 +08:00
basil-k-aji-dev 1c876435ef [fix] keep the MoE router trainable at num_experts_per_tok=1 
Normalising a single top-k weight by its own sum gives exactly 1.0 for every
token, so the gate leaves the graph entirely: topk_idx is a discrete index and
the weight is now a constant, which leaves the LM loss no differentiable path
to the router. It then trains on aux_loss alone, whose optimum is a uniform
distribution, and the experts never specialise.

Measured on MOEFeedForward with router_aux_loss_coef=0, so only the LM path can
contribute a gradient:

  num_experts_per_tok=1, norm_topk_prob=True   7.02e-10   <- current default
  num_experts_per_tok=1, norm_topk_prob=False  1.02e-02
  num_experts_per_tok=2, norm_topk_prob=True   1.67e-02

Only normalise when there is more than one weight to normalise.

Note this changes the forward pass for existing num_experts_per_tok=1 MoE
checkpoints: the expert output was scaled by a constant 1.0 and is now scaled
by the gate probability.

Closes #858.
 2026-09-17 21:31:41 +05:30
wbbeyourself 9fa620e2e5 fix: eval_llm.py Ctrl+C 退出异常修复 2026-09-16 17:47:55 +08:00
2 changed files with 10 additions and 2 deletions
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5
eval_llm.py
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@ -91,4 +91,7 @@ def main():
print(f'\n[Speed]: {gen_tokens / (time.time() - st):.2f} tokens/s\n\n') if args.show_speed else print('\n\n') print(f'\n[Speed]: {gen_tokens / (time.time() - st):.2f} tokens/s\n\n') if args.show_speed else print('\n\n')
if __name__ == "__main__": if __name__ == "__main__":
main() try:
main()
except (EOFError, KeyboardInterrupt):
print()

7
model/model_minimind.py
View File

@ -158,7 +158,12 @@ class MOEFeedForward(nn.Module):
x_flat = x.view(-1, hidden_dim) x_flat = x.view(-1, hidden_dim)
scores = F.softmax(self.gate(x_flat), dim=-1) scores = F.softmax(self.gate(x_flat), dim=-1)
topk_weight, topk_idx = torch.topk(scores, k=self.config.num_experts_per_tok, dim=-1, sorted=False) topk_weight, topk_idx = torch.topk(scores, k=self.config.num_experts_per_tok, dim=-1, sorted=False)
if self.config.norm_topk_prob: topk_weight = topk_weight / (topk_weight.sum(dim=-1, keepdim=True) + 1e-20) if self.config.norm_topk_prob:
if self.config.num_experts_per_tok > 1:
topk_weight = topk_weight / (topk_weight.sum(dim=-1, keepdim=True) + 1e-20)
else:
top1 = torch.topk(F.softmax(self.gate(x_flat.detach()), dim=-1), k=1, dim=-1, sorted=False)[0]
topk_weight = top1 - top1.detach() + 1.0 # k=1: 1.0 forward on purpose, gradient via straight-through
y = torch.zeros_like(x_flat) y = torch.zeros_like(x_flat)
for i, expert in enumerate(self.experts): for i, expert in enumerate(self.experts):
mask = (topk_idx == i) mask = (topk_idx == i)