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Merge pull request #490 from huggingface/better_finetuning_GPT_GPT-2

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Clean up GPT and GPT-2 losses computation
This commit is contained in:
Thomas Wolf
2019-04-15 16:14:50 +02:00
committed by GitHub
parent 6b35cfd28f fe2756ff41
commit 64b6ef4db0
1 changed files with 6 additions and 7 deletions
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13
pytorch_pretrained_bert/modeling_openai.py
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@@ -608,6 +608,7 @@ class OpenAIGPTModel(OpenAIGPTPreTrainedModel):
# Build new embeddings and initialize all new embeddings (in particular the special tokens)
old_embed = self.tokens_embed
self.tokens_embed = nn.Embedding(self.config.total_tokens_embeddings, self.config.n_embd)
self.tokens_embed.to(old_embed.weight.device)
self.init_weights(self.tokens_embed)
# Copy word embeddings from the previous weights
self.tokens_embed.weight.data[:self.config.vocab_size, :] = old_embed.weight.data[:self.config.vocab_size, :]
@@ -715,9 +716,8 @@ class OpenAIGPTLMHeadModel(OpenAIGPTPreTrainedModel):
lm_logits = self.lm_head(hidden_states)
if lm_labels is not None:
# Shift so that tokens < n predict n
shift_logits = lm_logits[:, :-1].contiguous()
shift_labels = lm_labels[:, 1:].contiguous()
shift_logits = lm_logits[..., :-1, :].contiguous()
shift_labels = lm_labels[..., 1:].contiguous()
# Flatten the tokens
loss_fct = CrossEntropyLoss(ignore_index=-1)
loss = loss_fct(shift_logits.view(-1, shift_logits.size(-1)),
@@ -807,11 +807,10 @@ class OpenAIGPTDoubleHeadsModel(OpenAIGPTPreTrainedModel):
mc_logits = self.multiple_choice_head(hidden_states, mc_token_ids)
losses = []
if lm_labels is not None:
shift_logits = lm_logits[:, :-1].contiguous()
shift_labels = lm_labels[:, 1:].contiguous()
shift_logits = lm_logits[..., :-1, :].contiguous()
shift_labels = lm_labels[..., 1:].contiguous()
loss_fct = CrossEntropyLoss(ignore_index=-1)
losses.append(loss_fct(shift_logits.view(-1,
shift_logits.size(-1)), shift_labels.view(-1)))
losses.append(loss_fct(shift_logits.view(-1, shift_logits.size(-1)), shift_labels.view(-1)))
if mc_labels is not None:
loss_fct = CrossEntropyLoss()
losses.append(loss_fct(mc_logits.view(-1, mc_logits.size(-1)), mc_labels.view(-1)))