def test_encode(self):
r"""Tests encoding.
"""
# case 1: GPT2 small
hparams = {
"pretrained_model_name": None,
}
encoder = GPT2Encoder(hparams=hparams)
inputs = torch.randint(30521, (self.batch_size, self.max_length))
outputs = encoder(inputs)
self.assertEqual(
outputs.shape,
torch.Size([self.batch_size, self.max_length,
encoder.output_size]))
# case 2: self-designed GPT2
hparams = {
'pretrained_model_name': None,
'embed': {
'dim': 96,
},
'position_embed': {
'dim': 96,
},
'encoder': {
'dim': 96,
'multihead_attention': {
'num_units': 96,
'output_dim': 96,
},
'poswise_feedforward': {
'layers': [{
'kwargs': {
'in_features': 96,
'out_features': 96 * 4,
'bias': True,
},
'type': 'Linear',
}, {
"type": "GPTGELU"
}, {
'kwargs': {
'in_features': 96 * 4,
'out_features': 96,
'bias': True,
},
'type': 'Linear',
}]
},
}
}
encoder = GPT2Encoder(hparams=hparams)
outputs = encoder(inputs)
self.assertEqual(
outputs.shape,
torch.Size([self.batch_size, self.max_length,
encoder.output_size]))
def test_trainable_variables(self):
r"""Tests the functionality of automatically collecting trainable
variables.
"""
def get_variable_num(n_layers: int) -> int:
return 1 + 1 + n_layers * 16 + 2
# case 1: GPT2 117M
encoder = GPT2Encoder()
self.assertEqual(len(encoder.trainable_variables),
get_variable_num(12))
_ = encoder(self.inputs)
# case 2: GPT2 345M
hparams = {
"pretrained_model_name": "345M",
}
encoder = GPT2Encoder(hparams=hparams)
self.assertEqual(len(encoder.trainable_variables),
get_variable_num(24))
_ = encoder(self.inputs)
# case 3: self-designed GPT2
hparams = {
"pretrained_model_name": None,
"num_blocks": 6,
}
encoder = GPT2Encoder(hparams=hparams)
self.assertEqual(len(encoder.trainable_variables), get_variable_num(6))
_ = encoder(self.inputs)
def test_hparams(self):
r"""Tests the priority of the encoder arch parameter.
"""
# case 1: set "pretrained_mode_name" by constructor argument
hparams = {
"pretrained_model_name": "345M",
}
encoder = GPT2Encoder(pretrained_model_name="117M", hparams=hparams)
self.assertEqual(encoder.hparams.num_blocks, 12)
_ = encoder(self.inputs)
# case 2: set "pretrained_mode_name" by hparams
hparams = {
"pretrained_model_name": "117M",
"num_blocks": 6,
}
encoder = GPT2Encoder(hparams=hparams)
self.assertEqual(encoder.hparams.num_blocks, 12)
_ = encoder(self.inputs)
# case 3: set to None in both hparams and constructor argument
hparams = {
"pretrained_model_name": None,
"num_blocks": 6,
}
encoder = GPT2Encoder(hparams=hparams)
self.assertEqual(encoder.hparams.num_blocks, 6)
_ = encoder(self.inputs)
# case 4: using default hparams
encoder = GPT2Encoder()
self.assertEqual(encoder.hparams.num_blocks, 12)
_ = encoder(self.inputs)
def test_model_loading(self):
r"""Tests model loading functionality."""
# case 1
encoder = GPT2Encoder(pretrained_model_name="117M")
_ = encoder(self.inputs)
# case 2
encoder = GPT2Encoder(pretrained_model_name="345M")
_ = encoder(self.inputs)
def __init__(self,
pretrained_model_name: Optional[str] = None,
cache_dir: Optional[str] = None,
hparams=None):
super().__init__(hparams=hparams)
# Create the underlying encoder
encoder_hparams = dict_fetch(hparams, GPT2Encoder.default_hparams())
self._encoder = GPT2Encoder(pretrained_model_name=pretrained_model_name,
cache_dir=cache_dir,
hparams=encoder_hparams)
# Create a dropout layer
self._dropout_layer = nn.Dropout(self._hparams.dropout)
# Create an additional classification layer if needed
self.num_classes = self._hparams.num_classes
if self.num_classes <= 0:
self._logits_layer = None
else:
logit_kwargs = self._hparams.logit_layer_kwargs
if logit_kwargs is None:
logit_kwargs = {}
elif not isinstance(logit_kwargs, HParams):
raise ValueError("hparams['logit_layer_kwargs'] "
"must be a dict.")
else:
logit_kwargs = logit_kwargs.todict()
if self._hparams.clas_strategy == 'all_time':
self._logits_layer = nn.Linear(
self._encoder.output_size *
self._hparams.max_seq_length,
self.num_classes,
**logit_kwargs)
else:
self._logits_layer = nn.Linear(
self._encoder.output_size, self.num_classes,
**logit_kwargs)
if self._hparams.initializer:
initialize = get_initializer(self._hparams.initializer)
assert initialize is not None
if self._logits_layer is not None:
initialize(self._logits_layer.weight)
if self._logits_layer.bias is not None:
initialize(self._logits_layer.bias)
self.is_binary = (self.num_classes == 1) or \
(self.num_classes <= 0 and
self._hparams.dim == 1)
def test_soft_ids(self):
r"""Tests soft ids.
"""
hparams = {
"pretrained_model_name": None,
}
encoder = GPT2Encoder(hparams=hparams)
inputs = torch.rand(self.batch_size, self.max_length, 50257)
outputs = encoder(inputs)
self.assertEqual(
outputs.shape,
torch.Size([self.batch_size, self.max_length, encoder.output_size]))
def default_hparams():
r"""Returns a dictionary of hyperparameters with default values.
.. code-block:: python
{
# (1) Same hyperparameters as in GPT2Encoder
...
# (2) Additional hyperparameters
"num_classes": 2,
"logit_layer_kwargs": None,
"clas_strategy": `cls_time`,
"max_seq_length": None,
"dropout": 0.1,
"name": `gpt2_classifier`
}
Here:
1. Same hyperparameters as in
:class:`~texar.torch.modules.GPT2Encoder`.
See the :meth:`~texar.torch.modules.GPT2Encoder.default_hparams`.
An instance of GPT2Encoder is created for feature extraction.
2. Additional hyperparameters:
`"num_classes"`: int
Number of classes:
- If **> 0**, an additional `Linear`
layer is appended to the encoder to compute the logits over
classes.
- If **<= 0**, no dense layer is appended. The number of
classes is assumed to be the final dense layer size of the
encoder.
`"logit_layer_kwargs"`: dict
Keyword arguments for the logit Dense layer constructor,
except for argument "units" which is set to `num_classes`.
Ignored if no extra logit layer is appended.
`"clas_strategy"`: str
The classification strategy, one of:
- **cls_time**: Sequence-level classification based on the
output of the last time step. Each sequence has a class.
- **all_time**: Sequence-level classification based on
the output of all time steps. Each sequence has a class.
- **time_wise**: Step-wise classification, i.e., make
classification for each time step based on its output.
`"max_seq_length"`: int, optional
Maximum possible length of input sequences. Required if
`clas_strategy` is `all_time`.
`"dropout"`: float
The dropout rate of the GPT2 encoder output.
`"name"`: str
Name of the classifier.
"""
hparams = GPT2Encoder.default_hparams()
hparams.update({
"num_classes": 2,
"logit_layer_kwargs": None,
"clas_strategy": "cls_time",
"max_seq_length": None,
"dropout": 0.1,
"name": "gpt2_classifier"
})
return hparams
def test_model_loading(self):
r"""Tests model loading functionality."""
for pretrained_model_name in GPT2Encoder.available_checkpoints():
encoder = GPT2Encoder(pretrained_model_name=pretrained_model_name)
_ = encoder(self.inputs)
