[Marian Fixes] prevent predicting pad_token_id before softmax, support language codes, name multilingual models (#4290)

src/transformers/modeling_utils.py

@@ -744,8 +744,8 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin):
     def prepare_inputs_for_generation(self, input_ids, **kwargs):
         return {"input_ids": input_ids}
 
-    def prepare_scores_for_generation(self, scores, **kwargs):
-        return scores
+    def prepare_logits_for_generation(self, logits, **kwargs):
+        return logits
 
     def _use_cache(self, outputs, use_cache):
         """During generation, decide whether to pass the `past` variable to the next forward pass."""
@@ -857,7 +857,7 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin):
                 ``1`` for tokens that are NOT MASKED, ``0`` for MASKED tokens.
                 Defaults to `None`.
 
-            `What are attention masks? <../glossary.html#attention-mask>`__
+                `What are attention masks? <../glossary.html#attention-mask>`__
 
             decoder_start_token_id=None: (`optional`) int
                 If an encoder-decoder model starts decoding with a different token than BOS.
@@ -1342,10 +1342,13 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin):
             if temperature != 1.0:
                 next_token_logits = next_token_logits / temperature
 
-            scores = F.log_softmax(next_token_logits, dim=-1)  # (batch_size * num_beams, vocab_size)
             if self.config.is_encoder_decoder and do_sample is False:
-                # TODO (PVP) still a bit hacky here - there might be a better solutino
-                scores = self.prepare_scores_for_generation(scores, cur_len=cur_len, max_length=max_length)
+                # TODO (PVP) still a bit hacky here - there might be a better solution
+                next_token_logits = self.prepare_logits_for_generation(
+                    next_token_logits, cur_len=cur_len, max_length=max_length
+                )
+
+            scores = F.log_softmax(next_token_logits, dim=-1)  # (batch_size * num_beams, vocab_size)
 
             # set eos token prob to zero if min_length is not reached
             if eos_token_id is not None and cur_len < min_length: