Make the core wav2vec2 factory function public (#1829)

This commit makes the following changes
1. Make the factory function with full customizability public.
    i.e. `_get_model(...) -> wav2vec2_model(...)`.
2. Change the other architecture-specific factory functions so that they accept parameters not related to the model architecture (such as dropout).
    i.e. `wav2vec2_base() -> wav2vec2_base(encoder_projection_dropout, encoder_attention_dropout, encoder_ff_interm_dropout, ...)`

### Why?

While adding the pre-trained weight support, I realized that separating API for model construction and pre-trained support achieves simple code organization because of the good separation of concern. As mentioned in #1821, in this framework,
  1. Model implementation is responsible for computation logic,
  2. factory functions are responsible for customizability and model construction,
  3. and pre-trained weight API is responsible for constructing a model and loading pre-trained weights along with the complementary information (such as pre-processing and class labels).

(note: for simple models, combining 1 and 2 is also okay.)

This means that factory functions has to support all the customizability required by pre-trained weight API. The current implementation uses the internal function like `from .model import Wav2Vec2Model, _get_model`, which is a bit strange.

This PR rectifies it by making the mother factory function public.
This also clarifies the purpose of having the other factory functions as public API, which is just a syntax sugar for constructing un-trained model with specific architecture. So this commit also adds supplemental parameters to them.

docs/source/models.rst

@@ -75,6 +75,12 @@ Wav2Vec2Model
 Factory Functions
 -----------------
 
+wav2vec2_model
+^^^^^^^^^^^^^^
+
+.. autofunction:: wav2vec2_model
+
+
 wav2vec2_base
 ^^^^^^^^^^^^^
 

test/torchaudio_unittest/models/wav2vec2/fairseq_integration_test.py

@@ -226,7 +226,7 @@ class TestFairseqIntegration(TorchaudioTestCase):
         original = self._get_model(config, num_out).eval()
         imported = import_fairseq_model(original).eval()
 
-        reloaded = factory_func(num_out=num_out)
+        reloaded = factory_func(aux_num_out=num_out)
         reloaded.load_state_dict(imported.state_dict())
         reloaded.eval()
 

test/torchaudio_unittest/models/wav2vec2/huggingface_intergration_test.py

@@ -221,7 +221,7 @@ class TestHFIntegration(TorchaudioTestCase):
     def test_recreate_finetune(self, config, factory_func):
         """Imported models can be recreated via a factory function without Hugging Face transformers."""
         imported = import_huggingface_model(self._get_model(config)).eval()
-        reloaded = factory_func(num_out=imported.aux.out_features)
+        reloaded = factory_func(aux_num_out=imported.aux.out_features)
         reloaded.load_state_dict(imported.state_dict())
         reloaded.eval()
         self._test_recreate(imported, reloaded, config)

test/torchaudio_unittest/models/wav2vec2/model_test.py

@@ -74,7 +74,7 @@ class TestWav2Vec2Model(TorchaudioTestCase):
     def test_cpu_smoke_test(self, dtype):
         model = wav2vec2_base()
         self._smoke_test(model, torch.device('cpu'), dtype)
-        model = wav2vec2_ft_base(num_out=32)
+        model = wav2vec2_ft_base(aux_num_out=32)
         self._smoke_test(model, torch.device('cpu'), dtype)
 
     @parameterized.expand([(torch.float32, ), (torch.float64, )])
@@ -82,7 +82,7 @@ class TestWav2Vec2Model(TorchaudioTestCase):
     def test_cuda_smoke_test(self, dtype):
         model = wav2vec2_base()
         self._smoke_test(model, torch.device('cuda'), dtype)
-        model = wav2vec2_ft_base(num_out=32)
+        model = wav2vec2_ft_base(aux_num_out=32)
         self._smoke_test(model, torch.device('cuda'), dtype)
 
     def _feature_extractor_test(self, model):
@@ -120,7 +120,7 @@ class TestWav2Vec2Model(TorchaudioTestCase):
     @finetune_factory_funcs
     def test_finetune_feature_extractor_test(self, factory_func):
         """`extract_features` method does not fail"""
-        self._feature_extractor_test(factory_func(num_out=32))
+        self._feature_extractor_test(factory_func(aux_num_out=32))
 
     def _test_batch_consistency(self, model):
         model.eval()
@@ -173,7 +173,7 @@ class TestWav2Vec2Model(TorchaudioTestCase):
     @finetune_factory_funcs
     def test_finetune_zero_length(self, factory_func):
         """Passing zero length should not fail"""
-        self._test_zero_length(factory_func(num_out=32))
+        self._test_zero_length(factory_func(aux_num_out=32))
 
     def _test_torchscript(self, model):
         model.eval()
@@ -209,7 +209,7 @@ class TestWav2Vec2Model(TorchaudioTestCase):
             self.skipTest(
                 'hubert_ft_xlarge is known to fail on Windows CI. '
                 'See https://github.com/pytorch/pytorch/issues/65776')
-        self._test_torchscript(factory_func(num_out=32))
+        self._test_torchscript(factory_func(aux_num_out=32))
 
     def _test_quantize_smoke_test(self, model):
         model.eval()
@@ -239,7 +239,7 @@ class TestWav2Vec2Model(TorchaudioTestCase):
     @skipIfNoQengine
     def test_finetune_quantize(self, factory_func):
         """Wav2Vec2Model should support basic quantization"""
-        self._test_quantize_smoke_test(factory_func(num_out=32))
+        self._test_quantize_smoke_test(factory_func(aux_num_out=32))
 
     def _test_quantize_torchscript(self, model):
         model.eval()
@@ -278,4 +278,4 @@ class TestWav2Vec2Model(TorchaudioTestCase):
     @skipIfNoQengine
     def test_finetune_quantize_torchscript(self, factory_func):
         """Quantized Wav2Vec2Model should be scriptable"""
-        self._test_quantize_torchscript(factory_func(num_out=32))
+        self._test_quantize_torchscript(factory_func(aux_num_out=32))

torchaudio/models/__init__.py

@@ -5,6 +5,7 @@ from .deepspeech import DeepSpeech
 from .tacotron2 import Tacotron2, tacotron2
 from .wav2vec2 import (
     Wav2Vec2Model,
+    wav2vec2_model,
     wav2vec2_ft_base,
     wav2vec2_ft_large,
     wav2vec2_ft_large_lv60k,
@@ -46,6 +47,7 @@ __all__ = [
     'ConvTasNet',
     'DeepSpeech',
     'Wav2Vec2Model',
+    'wav2vec2_model',
     'wav2vec2_ft_base',
     'wav2vec2_ft_large',
     'wav2vec2_ft_large_lv60k',

torchaudio/models/wav2vec2/__init__.py

 from .model import (
     Wav2Vec2Model,
+    wav2vec2_model,
     wav2vec2_ft_base,
     wav2vec2_ft_large,
     wav2vec2_ft_large_lv60k,
@@ -16,6 +17,7 @@ from . import utils
 
 __all__ = [
     'Wav2Vec2Model',
+    'wav2vec2_model',
     'wav2vec2_ft_base',
     'wav2vec2_ft_large',
     'wav2vec2_ft_large_lv60k',

torchaudio/models/wav2vec2/pretrained.py

@@ -3,7 +3,7 @@ from typing import Dict, Tuple, Any, Optional
 
 from torch.hub import load_state_dict_from_url
 
-from .model import _get_model, Wav2Vec2Model
+from .model import wav2vec2_model, Wav2Vec2Model
 
 __all__ = []
 
@@ -67,7 +67,7 @@ class Wav2Vec2PretrainedModelBundle:
         Args:
             dl_kwargs (dictionary of keyword arguments): Passed to :func:`torch.hub.load_state_dict_from_url`.
         """
-        model = _get_model(**self._params)
+        model = wav2vec2_model(**self._params)
         url = f'https://download.pytorch.org/models/audio/{self._path}'
         dl_kwargs = {} if dl_kwargs is None else dl_kwargs
         state_dict = load_state_dict_from_url(url, **dl_kwargs)

torchaudio/models/wav2vec2/utils/import_fairseq.py

@@ -6,7 +6,7 @@ import re
 
 from torch.nn import Module
 
-from ..model import Wav2Vec2Model, _get_model
+from ..model import Wav2Vec2Model, wav2vec2_model
 
 
 def _parse_config(w2v_model):
@@ -190,27 +190,27 @@ def import_fairseq_model(original: Module) -> Wav2Vec2Model:
 
 def _import_wav2vec2_finetuning(original: Module) -> Wav2Vec2Model:
     config = _parse_config(original.w2v_model)
-    model = _get_model(**config, aux_num_out=original.proj.out_features)
+    model = wav2vec2_model(**config, aux_num_out=original.proj.out_features)
     model.load_state_dict(_convert_state_dict(original.state_dict()))
     return model
 
 
 def _import_wav2vec2_pretraining(original: Module) -> Wav2Vec2Model:
     config = _parse_config(original)
-    model = _get_model(**config, aux_num_out=None)
+    model = wav2vec2_model(**config, aux_num_out=None)
     model.load_state_dict(_convert_state_dict(original.state_dict()), strict=False)
     return model
 
 
 def _import_hubert_finetuning(original: Module) -> Wav2Vec2Model:
     config = _parse_config(original.w2v_model)
-    model = _get_model(**config, aux_num_out=original.proj.out_features)
+    model = wav2vec2_model(**config, aux_num_out=original.proj.out_features)
     model.load_state_dict(_convert_state_dict(original.state_dict()), strict=False)
     return model
 
 
 def _import_hubert_pretraining(original: Module) -> Wav2Vec2Model:
     config = _parse_config(original)
-    model = _get_model(**config, aux_num_out=None)
+    model = wav2vec2_model(**config, aux_num_out=None)
     model.load_state_dict(_convert_state_dict(original.state_dict()), strict=False)
     return model

torchaudio/models/wav2vec2/utils/import_huggingface.py

@@ -4,7 +4,7 @@ import logging
 
 from torch.nn import Module
 
-from ..model import Wav2Vec2Model, _get_model
+from ..model import Wav2Vec2Model, wav2vec2_model
 
 _LG = logging.getLogger(__name__)
 
@@ -40,7 +40,7 @@ def _build(config, original):
             '"lm_head" module is not imported.')
         aux_num_out = None
         wav2vec2 = original
-    imported = _get_model(**config, aux_num_out=aux_num_out)
+    imported = wav2vec2_model(**config, aux_num_out=aux_num_out)
     imported.feature_extractor.load_state_dict(wav2vec2.feature_extractor.state_dict())
     imported.encoder.feature_projection.load_state_dict(wav2vec2.feature_projection.state_dict())
     imported.encoder.transformer.load_state_dict(wav2vec2.encoder.state_dict())