[Generation] Allow `inputs_embeds` as an input (#14443)

* up

* finalize

* finalize

* finish

* Update src/transformers/generation_utils.py

* apply feedback

src/transformers/generation_utils.py

@@ -392,14 +392,25 @@ class GenerationMixin:
         return torch.ones((1, 1), dtype=torch.long, device=self.device) * bos_token_id
 
     def _prepare_attention_mask_for_generation(
-        self, input_ids: torch.Tensor, pad_token_id: int, eos_token_id: int
+        self,
+        input_ids: torch.Tensor,
+        pad_token_id: int,
+        eos_token_id: int,
+        inputs_embeds: Optional[torch.Tensor] = None,
     ) -> torch.LongTensor:
+
+        # First if `inputs_embeds` are given, but no `attention_mask` assume that full attention_mask is used
+        if inputs_embeds is not None:
+            return torch.ones((inputs_embeds.shape[0], inputs_embeds.shape[1]), dtype=torch.long)
+
+        # Otherwise, use `input_ids`
         is_pad_token_in_inputs_ids = (pad_token_id is not None) and (pad_token_id in input_ids)
         is_pad_token_not_equal_to_eos_token_id = (eos_token_id is None) or (
             (eos_token_id is not None) and (pad_token_id != eos_token_id)
         )
         if is_pad_token_in_inputs_ids and is_pad_token_not_equal_to_eos_token_id:
             return input_ids.ne(pad_token_id).long()
+        else:
             return input_ids.new_ones(input_ids.shape, dtype=torch.long)
 
     def _prepare_encoder_decoder_kwargs_for_generation(
@@ -417,12 +428,11 @@ class GenerationMixin:
         return model_kwargs
 
     def _prepare_decoder_input_ids_for_generation(
-        self, input_ids: torch.LongTensor, decoder_start_token_id: int = None, bos_token_id: int = None
+        self, batch_size: int, decoder_start_token_id: int = None, bos_token_id: int = None
     ) -> torch.LongTensor:
         decoder_start_token_id = self._get_decoder_start_token_id(decoder_start_token_id, bos_token_id)
-        decoder_input_ids = (
-            torch.ones((input_ids.shape[0], 1), dtype=torch.long, device=input_ids.device) * decoder_start_token_id
-        )
+
+        decoder_input_ids = torch.ones((batch_size, 1), dtype=torch.long, device=self.device) * decoder_start_token_id
         return decoder_input_ids
 
     def _get_pad_token_id(self, pad_token_id: int = None, eos_token_id: int = None) -> int:
@@ -890,8 +900,9 @@ class GenerationMixin:
 
         if model_kwargs.get("attention_mask", None) is None:
             # init `attention_mask` depending on `pad_token_id`
+            inputs_embeds = model_kwargs.get("inputs_embeds", None)
             model_kwargs["attention_mask"] = self._prepare_attention_mask_for_generation(
-                input_ids, pad_token_id, eos_token_id
+                input_ids, pad_token_id, eos_token_id, inputs_embeds
             )
 
         # special case if pad_token_id is not defined
@@ -910,12 +921,17 @@ class GenerationMixin:
             if "decoder_input_ids" in model_kwargs:
                 input_ids = model_kwargs.pop("decoder_input_ids")
             else:
+                # if word embeddings are provided directly, infere the batch size from it
+                batch_size = input_ids.shape[0] if input_ids is not None else model_kwargs["inputs_embeds"].shape[0]
                 input_ids = self._prepare_decoder_input_ids_for_generation(
-                    input_ids, decoder_start_token_id=decoder_start_token_id, bos_token_id=bos_token_id
+                    batch_size, decoder_start_token_id=decoder_start_token_id, bos_token_id=bos_token_id
                 )
 
             if "encoder_outputs" not in model_kwargs or not isinstance(model_kwargs["encoder_outputs"], ModelOutput):
                 raise ValueError("Make sure that `model_kwargs` include `encoder_outputs` of type `ModelOutput`.")
+        else:
+            if "inputs_embeds" in model_kwargs and input_ids is None:
+                raise ValueError("For decoder-only generation, one must pass `input_ids`.")
 
         # if `max_new_tokens` is passed, but not `max_length` -> set `max_length = max_new_tokens`
         if max_length is None and max_new_tokens is not None:

tests/test_generation_utils.py

@@ -1388,15 +1388,17 @@ class GenerationIntegrationTests(unittest.TestCase):
 
     def test_max_length_backward_compat_greedy(self):
         article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
-        bart_tokenizer = BartTokenizer.from_pretrained("sshleifer/bart-tiny-random")
-        bart_model = BartForConditionalGeneration.from_pretrained("sshleifer/bart-tiny-random").to(torch_device)
+        bart_tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        bart_model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart").to(
+            torch_device
+        )
         input_ids = bart_tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
 
         max_length = 20
         input_ids = input_ids.expand(2, -1)
         model_kwargs = bart_model._prepare_encoder_decoder_kwargs_for_generation(input_ids, {})
         input_ids = bart_model._prepare_decoder_input_ids_for_generation(
-            input_ids,
+            input_ids.shape[0],
             decoder_start_token_id=bart_model.config.decoder_start_token_id,
             bos_token_id=bart_model.config.bos_token_id,
         )
@@ -1412,15 +1414,17 @@ class GenerationIntegrationTests(unittest.TestCase):
 
     def test_max_length_backward_compat_sample(self):
         article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
-        bart_tokenizer = BartTokenizer.from_pretrained("sshleifer/bart-tiny-random")
-        bart_model = BartForConditionalGeneration.from_pretrained("sshleifer/bart-tiny-random").to(torch_device)
+        bart_tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        bart_model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart").to(
+            torch_device
+        )
         input_ids = bart_tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
 
         max_length = 20
         input_ids = input_ids.expand(2, -1)
         model_kwargs = bart_model._prepare_encoder_decoder_kwargs_for_generation(input_ids, {})
         input_ids = bart_model._prepare_decoder_input_ids_for_generation(
-            input_ids,
+            input_ids.shape[0],
             decoder_start_token_id=bart_model.config.decoder_start_token_id,
             bos_token_id=bart_model.config.bos_token_id,
         )
@@ -1436,8 +1440,10 @@ class GenerationIntegrationTests(unittest.TestCase):
 
     def test_max_length_backward_compat_beam_search(self):
         article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
-        bart_tokenizer = BartTokenizer.from_pretrained("sshleifer/bart-tiny-random")
-        bart_model = BartForConditionalGeneration.from_pretrained("sshleifer/bart-tiny-random").to(torch_device)
+        bart_tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        bart_model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart").to(
+            torch_device
+        )
         input_ids = bart_tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
 
         batch_size = 1
@@ -1447,7 +1453,7 @@ class GenerationIntegrationTests(unittest.TestCase):
         input_ids = input_ids.expand(2, -1)
         model_kwargs = bart_model._prepare_encoder_decoder_kwargs_for_generation(input_ids, {})
         input_ids = bart_model._prepare_decoder_input_ids_for_generation(
-            input_ids,
+            input_ids.shape[0],
             decoder_start_token_id=bart_model.config.decoder_start_token_id,
             bos_token_id=bart_model.config.bos_token_id,
         )
@@ -1464,8 +1470,10 @@ class GenerationIntegrationTests(unittest.TestCase):
 
     def test_max_length_backward_compat_group_beam_search(self):
         article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
-        bart_tokenizer = BartTokenizer.from_pretrained("sshleifer/bart-tiny-random")
-        bart_model = BartForConditionalGeneration.from_pretrained("sshleifer/bart-tiny-random").to(torch_device)
+        bart_tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        bart_model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart").to(
+            torch_device
+        )
         input_ids = bart_tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
 
         batch_size = 1
@@ -1477,7 +1485,7 @@ class GenerationIntegrationTests(unittest.TestCase):
         input_ids = input_ids.expand(6, -1)
         model_kwargs = bart_model._prepare_encoder_decoder_kwargs_for_generation(input_ids, {})
         input_ids = bart_model._prepare_decoder_input_ids_for_generation(
-            input_ids,
+            input_ids.shape[0],
             decoder_start_token_id=bart_model.config.decoder_start_token_id,
             bos_token_id=bart_model.config.bos_token_id,
         )
@@ -1496,8 +1504,10 @@ class GenerationIntegrationTests(unittest.TestCase):
 
     def test_max_length_warning_if_different(self):
         article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
-        bart_tokenizer = BartTokenizer.from_pretrained("sshleifer/bart-tiny-random")
-        bart_model = BartForConditionalGeneration.from_pretrained("sshleifer/bart-tiny-random").to(torch_device)
+        bart_tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        bart_model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart").to(
+            torch_device
+        )
         input_ids = bart_tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
 
         batch_size = 1
@@ -1513,7 +1523,7 @@ class GenerationIntegrationTests(unittest.TestCase):
         input_ids = input_ids.expand(6, -1)
         model_kwargs = bart_model._prepare_encoder_decoder_kwargs_for_generation(input_ids, {})
         input_ids = bart_model._prepare_decoder_input_ids_for_generation(
-            input_ids,
+            input_ids.shape[0],
             decoder_start_token_id=bart_model.config.decoder_start_token_id,
             bos_token_id=bart_model.config.bos_token_id,
         )
@@ -1577,8 +1587,10 @@ class GenerationIntegrationTests(unittest.TestCase):
 
     def test_beam_search_warning_if_max_length_is_passed(self):
         article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
-        bart_tokenizer = BartTokenizer.from_pretrained("sshleifer/bart-tiny-random")
-        bart_model = BartForConditionalGeneration.from_pretrained("sshleifer/bart-tiny-random").to(torch_device)
+        bart_tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        bart_model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart").to(
+            torch_device
+        )
 
         batch_size = 1
         num_beams = 3
@@ -1587,6 +1599,9 @@ class GenerationIntegrationTests(unittest.TestCase):
         input_ids = input_ids.expand(num_beams, -1)
         model_kwargs = bart_model._prepare_encoder_decoder_kwargs_for_generation(input_ids, {})
 
+        # pretend decoder_input_ids correspond to first encoder input id
+        decoder_input_ids = input_ids[:, :1]
+
         stopping_criteria_max_length = 18
         stopping_criteria = StoppingCriteriaList([MaxLengthCriteria(max_length=stopping_criteria_max_length)])
 
@@ -1599,7 +1614,7 @@ class GenerationIntegrationTests(unittest.TestCase):
             )
 
         generated_ids = bart_model.beam_search(
-            input_ids,
+            decoder_input_ids,
             num_beams=num_beams,
             stopping_criteria=stopping_criteria,
             beam_scorer=beam_scorer,
@@ -1613,7 +1628,7 @@ class GenerationIntegrationTests(unittest.TestCase):
         )
 
         generated_ids_no_max_len = bart_model.beam_search(
-            input_ids,
+            decoder_input_ids,
             num_beams=num_beams,
             stopping_criteria=stopping_criteria,
             beam_scorer=beam_scorer_no_max_len,
@@ -1625,14 +1640,17 @@ class GenerationIntegrationTests(unittest.TestCase):
 
     def test_max_new_tokens_encoder_decoder(self):
         article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
-        bart_tokenizer = BartTokenizer.from_pretrained("sshleifer/bart-tiny-random")
-        bart_model = BartForConditionalGeneration.from_pretrained("sshleifer/bart-tiny-random").to(torch_device)
+        bart_tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        bart_model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart").to(
+            torch_device
+        )
         input_ids = bart_tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
 
-        self.assertEqual(list(input_ids.shape), [1, 15])
+        self.assertEqual(list(input_ids.shape), [1, 29])
 
         max_new_tokens = 3
         bart_model.config.max_length = 20
+        bart_model.config.eos_token_id = None
 
         # Encoder decoder call
         outputs = bart_model.generate(input_ids, max_new_tokens=max_new_tokens)
@@ -1641,8 +1659,8 @@ class GenerationIntegrationTests(unittest.TestCase):
 
         # Decoder only call
         outputs = bart_model.generate(decoder_input_ids=input_ids, max_new_tokens=max_new_tokens)
-        # 15 + 3 new tokens
-        self.assertEqual(list(outputs.shape), [1, 18])
+        # 29 + 3 new tokens
+        self.assertEqual(list(outputs.shape), [1, 32])
 
         # Encoder decoder call > 20
         outputs = bart_model.generate(max_new_tokens=max_new_tokens + 20)
@@ -1680,3 +1698,29 @@ class GenerationIntegrationTests(unittest.TestCase):
         # max_new_tokens and max_length serve the same purpose and should not be used together.
         with self.assertWarns(UserWarning):
             gpt2_model.generate(decoder_input_ids=input_ids, max_new_tokens=10, max_length=20)
+
+    def test_encoder_decoder_generate_with_inputs_embeds(self):
+        article = """Justin Timberlake and Jessica Biel, welcome to parenthood."""
+        tokenizer = BartTokenizer.from_pretrained("hf-internal-testing/tiny-random-bart")
+        model = BartForConditionalGeneration.from_pretrained("hf-internal-testing/tiny-random-bart", max_length=5).to(
+            torch_device
+        )
+        model.config.eos_token_id = None
+        input_ids = tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
+        inputs_embeds = model.get_input_embeddings()(input_ids)
+
+        output_sequences = model.generate(inputs_embeds=inputs_embeds)
+
+        # make sure model generated correctly until `max_length`
+        self.assertEqual(output_sequences.shape, (1, 5))
+
+    def test_decoder_generate_with_inputs_embeds(self):
+        article = """I need input_ids to generate"""
+        tokenizer = GPT2Tokenizer.from_pretrained("hf-internal-testing/tiny-random-gpt2")
+        model = GPT2LMHeadModel.from_pretrained("hf-internal-testing/tiny-random-gpt2", max_length=5).to(torch_device)
+        input_ids = tokenizer(article, return_tensors="pt").input_ids.to(torch_device)
+        inputs_embeds = model.get_input_embeddings()(input_ids)
+
+        # cannot generate from `inputs_embeds` for decoder only
+        with self.assertRaises(ValueError):
+            model.generate(inputs_embeds=inputs_embeds)