update special token addition

pytorch_pretrained_bert/modeling_openai.py

@@ -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.device.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, :]