Fixup generation utils for prototype release (#2065)

* Fixup generation utils for prototype release

* Move test under integration b/c relies on T5

* fix lint

Author: joecummings

test/torchtext_unittest/prototype/test_generate.py renamed to test/integration_tests/test_generate.py

@@ -2,7 +2,7 @@
 
 import torch
 from torchtext.models import T5_BASE_GENERATION
-from torchtext.prototype.generate import DEFAULT_MAX_SEQ_LEN, GenerationUtil
+from torchtext.prototype.generate import DEFAULT_MAX_SEQ_LEN, GenerationUtils
 from torchtext_unittest.common.torchtext_test_case import TorchtextTestCase
 
 
@@ -26,9 +26,9 @@ def setUp(self) -> None:
         torch.manual_seed(0)
 
     def test_greedy_generate_with_t5(self) -> None:
-        generation_model = GenerationUtil(self.model)
+        generation_model = GenerationUtils(self.model)
 
-        tokens = generation_model.generate(self.inputs, num_beams=1, max_len=30)
+        tokens = generation_model.generate(self.inputs, num_beams=1, max_length=30)
         generated_text = self.transform.decode(tokens.tolist())
 
         expected_generated_text = [
@@ -42,13 +42,13 @@ def test_greedy_generate_with_t5(self) -> None:
         self.assertEqual(generated_text, expected_generated_text)
 
     def test_generate_errors_with_incorrect_beams(self) -> None:
-        generation_model = GenerationUtil(self.model, is_encoder_decoder=True)
+        generation_model = GenerationUtils(self.model, is_encoder_decoder=True)
 
         with self.assertRaises(ValueError):
             generation_model.generate(self.inputs, num_beams=0)
 
     @patch("logging.Logger.warning")
     def test_warns_when_no_max_len_provided(self, mock) -> None:
-        generation_model = GenerationUtil(self.model)
+        generation_model = GenerationUtils(self.model)
         generation_model.generate(self.inputs)
-        mock.assert_called_with(f"`max_len` was not specified. Defaulting to {DEFAULT_MAX_SEQ_LEN} tokens.")
+        mock.assert_called_with(f"`max_length` was not specified. Defaulting to {DEFAULT_MAX_SEQ_LEN} tokens.")

torchtext/prototype/generate.py

@@ -10,13 +10,13 @@
 DEFAULT_MAX_SEQ_LEN = 256
 
 
-class GenerationUtil:
+class GenerationUtils:
     """Wrapper to provide generation utils for encoder/decoder models and decoder models.
 
     Example:
     >>> model = T5_BASE_GENERATION.get_model()
-    >>> generative_model = GenerationUtil(model=model)
-    >>> generative_model.generate(input_ids, num_beams=1, max_len=100)
+    >>> generative_model = GenerationUtils(model=model)
+    >>> generative_model.generate(input_ids, num_beams=1, max_length=100)
 
     The wrapper can work with *any* model as long as it meets the following requirements:
     1. Is an encoder/decoder or decoder based model.
@@ -26,15 +26,18 @@ class GenerationUtil:
     >>> from transformers import T5Model
     >>> model = T5Model.from_pretrained("t5-base")
     >>> generative_model = GenerationUtils(model=model, is_huggingface_model=True)
-    >>> generative_model.generate(input_ids, num_beams=1, max_len=100)
+    >>> generative_model.generate(input_ids, num_beams=1, max_length=100)
+
+    `Note`: We cannot make any claims about the stability of APIs from HuggingFace so all models used from the `transformers`
+        library are marked 'experimental.'
 
     More examples can be found in the `notebooks` directory of this repository.
     """
 
-    def __init__(self, model: nn.Module, is_encoder_decoder: bool = True, is_huggingface_model: bool = False) -> None:
+    def __init__(self, model: nn.Module, **kwargs) -> None:
         self.model = model
-        self.is_encoder_decoder = is_encoder_decoder
-        self.is_huggingface_model = is_huggingface_model
+        self.is_encoder_decoder = kwargs.pop("is_encoder_decoder", True)
+        self.is_huggingface_model = kwargs.pop("is_huggingface_model", False)
 
     def _prepare_decoder_ids_for_generation(
         self, batch_size: int, pad_idx: int = 0, device: Optional[torch.device] = None, **model_kwargs
@@ -45,13 +48,13 @@ def _prepare_decoder_ids_for_generation(
             return torch.ones((batch_size, 1), dtype=torch.long, device=device) * pad_idx
 
     def greedy_search(
-        self, input_ids: torch.Tensor, max_len: int, eos_idx: int, pad_idx: Optional[int] = None, **model_kwargs
+        self, input_ids: torch.Tensor, max_length: int, eos_idx: int, pad_idx: Optional[int] = None, **model_kwargs
     ) -> torch.Tensor:
         """Greedy search decoding for text generation. Takes the most likely next token every time.
 
         Inputs:
             input_ids (Tensor): Text prompt(s) for greedy generation.
-            max_len (int): Max length to generate responses.
+            max_length (int): Max length to generate responses.
             eos_idx (int): End of sequence index.
             pad_idx (int): Padding index.
             **model_kwargs
@@ -87,20 +90,20 @@ def greedy_search(
             if eos_idx is not None:
                 unfinished_sequences = unfinished_sequences.mul((next_tokens != eos_idx).long())
 
-            # Stop iterating once all sequences are finished or exceed the max_len
-            if unfinished_sequences.max() == 0 or len(input_ids[0]) >= max_len:
+            # Stop iterating once all sequences are finished or exceed the max_length
+            if unfinished_sequences.max() == 0 or len(input_ids[0]) >= max_length:
                 break
 
         return input_ids
 
-    def beam_search(self, input_ids: torch.Tensor, num_beams: int, max_len: Optional[int]) -> torch.Tensor:
+    def beam_search(self, input_ids: torch.Tensor, num_beams: int, max_length: Optional[int]) -> torch.Tensor:
         raise NotImplementedError()
 
     def generate(
         self,
         inputs: Optional[torch.Tensor] = None,
         num_beams: Optional[int] = None,
-        max_len: Optional[int] = None,
+        max_length: Optional[int] = None,
         pad_idx: int = 0,
         eos_idx: int = 1,
     ) -> torch.Tensor:
@@ -112,7 +115,7 @@ def generate(
         Args:
             input_ids (Tensor): Ids of tokenized input tokens. The 'seed' text for generation.
             num_beams (int): If provided, specifies the number of beams to use in beam search generation.
-            max_len (int): Max length to generate responses.
+            max_length (int): Max length to generate responses.
             pad_idx (int): Padding index. Defaults to 0.
             eos_idx (int): End of sequence index. Defaults to 1.
 
@@ -128,14 +131,14 @@ def generate(
             model_kwargs["encoder_outputs"] = encoder(inputs)
             inputs = self._prepare_decoder_ids_for_generation(len(inputs), device=inputs.device, **model_kwargs)
 
-        if max_len is None:
+        if max_length is None:
             # Too hard to try to figure out the exact max_seq_length for each model
-            logger.warning(f"`max_len` was not specified. Defaulting to {DEFAULT_MAX_SEQ_LEN} tokens.")
-            max_len = DEFAULT_MAX_SEQ_LEN
+            logger.warning(f"`max_length` was not specified. Defaulting to {DEFAULT_MAX_SEQ_LEN} tokens.")
+            max_length = DEFAULT_MAX_SEQ_LEN
 
         if num_beams == 1 or num_beams is None:
-            return self.greedy_search(inputs, max_len, eos_idx, pad_idx=pad_idx, **model_kwargs)
+            return self.greedy_search(inputs, max_length, eos_idx, pad_idx=pad_idx, **model_kwargs)
         elif num_beams > 1:
-            return self.beam_search(inputs, num_beams, max_len)
+            return self.beam_search(inputs, num_beams, max_length)
         else:
             raise ValueError("`num_beams` must be >= 1.")