# coding=utf-8 # Copyright 2018 Google AI, Google Brain and the HuggingFace Inc. team. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """PyTorch ALBERT model. """ import math import os from dataclasses import dataclass from typing import Optional, Tuple import torch from packaging import version from torch import nn from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss from transformers.activations import ACT2FN from transformers.file_utils import ( ModelOutput, add_code_sample_docstrings, add_start_docstrings, add_start_docstrings_to_model_forward, replace_return_docstrings, ) from transformers.modeling_outputs import ( BaseModelOutput, BaseModelOutputWithPooling, MaskedLMOutput, MultipleChoiceModelOutput, QuestionAnsweringModelOutput, SequenceClassifierOutput, TokenClassifierOutput, ) from transformers.modeling_utils import ( PreTrainedModel, apply_chunking_to_forward, find_pruneable_heads_and_indices, prune_linear_layer, ) from transformers.utils import logging from transformers import AlbertConfig logger = logging.get_logger(__name__) _CHECKPOINT_FOR_DOC = "albert-base-v2" _CONFIG_FOR_DOC = "AlbertConfig" _TOKENIZER_FOR_DOC = "AlbertTokenizer" ALBERT_PRETRAINED_MODEL_ARCHIVE_LIST = [ "albert-base-v1", "albert-large-v1", "albert-xlarge-v1", "albert-xxlarge-v1", "albert-base-v2", "albert-large-v2", "albert-xlarge-v2", "albert-xxlarge-v2", # See all ALBERT models at https://huggingface.co/models?filter=albert ] def load_tf_weights_in_albert(model, config, tf_checkpoint_path): """Load tf checkpoints in a pytorch model.""" try: import re import numpy as np import tensorflow as tf except ImportError: logger.error( "Loading a TensorFlow model in PyTorch, requires TensorFlow to be installed. Please see " "https://www.tensorflow.org/install/ for installation instructions." ) raise tf_path = os.path.abspath(tf_checkpoint_path) logger.info(f"Converting TensorFlow checkpoint from {tf_path}") # Load weights from TF model init_vars = tf.train.list_variables(tf_path) names = [] arrays = [] for name, shape in init_vars: logger.info(f"Loading TF weight {name} with shape {shape}") array = tf.train.load_variable(tf_path, name) names.append(name) arrays.append(array) for name, array in zip(names, arrays): print(name) for name, array in zip(names, arrays): original_name = name # If saved from the TF HUB module name = name.replace("module/", "") # Renaming and simplifying name = name.replace("ffn_1", "ffn") name = name.replace("bert/", "albert/") name = name.replace("attention_1", "attention") name = name.replace("transform/", "") name = name.replace("LayerNorm_1", "full_layer_layer_norm") name = name.replace("LayerNorm", "attention/LayerNorm") name = name.replace("transformer/", "") # The feed forward layer had an 'intermediate' step which has been abstracted away name = name.replace("intermediate/dense/", "") name = name.replace("ffn/intermediate/output/dense/", "ffn_output/") # ALBERT attention was split between self and output which have been abstracted away name = name.replace("/output/", "/") name = name.replace("/self/", "/") # The pooler is a linear layer name = name.replace("pooler/dense", "pooler") # The classifier was simplified to predictions from cls/predictions name = name.replace("cls/predictions", "predictions") name = name.replace("predictions/attention", "predictions") # Naming was changed to be more explicit name = name.replace("embeddings/attention", "embeddings") name = name.replace("inner_group_", "albert_layers/") name = name.replace("group_", "albert_layer_groups/") # Classifier if len(name.split("/")) == 1 and ("output_bias" in name or "output_weights" in name): name = "classifier/" + name # No ALBERT model currently handles the next sentence prediction task if "seq_relationship" in name: name = name.replace("seq_relationship/output_", "sop_classifier/classifier/") name = name.replace("weights", "weight") name = name.split("/") # Ignore the gradients applied by the LAMB/ADAM optimizers. if ( "adam_m" in name or "adam_v" in name or "AdamWeightDecayOptimizer" in name or "AdamWeightDecayOptimizer_1" in name or "global_step" in name ): logger.info(f"Skipping {'/'.join(name)}") continue pointer = model for m_name in name: if re.fullmatch(r"[A-Za-z]+_\d+", m_name): scope_names = re.split(r"_(\d+)", m_name) else: scope_names = [m_name] if scope_names[0] == "kernel" or scope_names[0] == "gamma": pointer = getattr(pointer, "weight") elif scope_names[0] == "output_bias" or scope_names[0] == "beta": pointer = getattr(pointer, "bias") elif scope_names[0] == "output_weights": pointer = getattr(pointer, "weight") elif scope_names[0] == "squad": pointer = getattr(pointer, "classifier") else: try: pointer = getattr(pointer, scope_names[0]) except AttributeError: logger.info(f"Skipping {'/'.join(name)}") continue if len(scope_names) >= 2: num = int(scope_names[1]) pointer = pointer[num] if m_name[-11:] == "_embeddings": pointer = getattr(pointer, "weight") elif m_name == "kernel": array = np.transpose(array) try: if pointer.shape != array.shape: raise ValueError(f"Pointer shape {pointer.shape} and array shape {array.shape} mismatched") except AssertionError as e: e.args += (pointer.shape, array.shape) raise print(f"Initialize PyTorch weight {name} from {original_name}") pointer.data = torch.from_numpy(array) return model class AlbertEmbeddings(nn.Module): """ Construct the embeddings from word, position and token_type embeddings. """ def __init__(self, config): super().__init__() self.word_embeddings = nn.Embedding(config.vocab_size, config.embedding_size, padding_idx=config.pad_token_id) self.position_embeddings = nn.Embedding(config.max_position_embeddings, config.embedding_size) self.token_type_embeddings = nn.Embedding(config.type_vocab_size, config.embedding_size) # self.LayerNorm is not snake-cased to stick with TensorFlow model variable name and be able to load # any TensorFlow checkpoint file self.LayerNorm = nn.LayerNorm(config.embedding_size, eps=config.layer_norm_eps) self.dropout = nn.Dropout(config.hidden_dropout_prob) # position_ids (1, len position emb) is contiguous in memory and exported when serialized self.register_buffer("position_ids", torch.arange(config.max_position_embeddings).expand((1, -1))) self.position_embedding_type = getattr(config, "position_embedding_type", "absolute") if version.parse(torch.__version__) > version.parse("1.6.0"): self.register_buffer( "token_type_ids", torch.zeros(self.position_ids.size(), dtype=torch.long, device=self.position_ids.device), persistent=False, ) # Copied from transformers.models.bert.modeling_bert.BertEmbeddings.forward def forward( self, input_ids=None, token_type_ids=None, position_ids=None, inputs_embeds=None, past_key_values_length=0 ): if input_ids is not None: input_shape = input_ids.size() else: input_shape = inputs_embeds.size()[:-1] seq_length = input_shape[1] if position_ids is None: position_ids = self.position_ids[:, past_key_values_length : seq_length + past_key_values_length] # Setting the token_type_ids to the registered buffer in constructor where it is all zeros, which usually occurs # when its auto-generated, registered buffer helps users when tracing the model without passing token_type_ids, solves # issue #5664 if token_type_ids is None: if hasattr(self, "token_type_ids"): buffered_token_type_ids = self.token_type_ids[:, :seq_length] buffered_token_type_ids_expanded = buffered_token_type_ids.expand(input_shape[0], seq_length) token_type_ids = buffered_token_type_ids_expanded else: token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=self.position_ids.device) if inputs_embeds is None: inputs_embeds = self.word_embeddings(input_ids) token_type_embeddings = self.token_type_embeddings(token_type_ids) embeddings = inputs_embeds + token_type_embeddings if self.position_embedding_type == "absolute": position_embeddings = self.position_embeddings(position_ids) embeddings += position_embeddings embeddings = self.LayerNorm(embeddings) embeddings = self.dropout(embeddings) return embeddings class AlbertAttention(nn.Module): def __init__(self, config): super().__init__() if config.hidden_size % config.num_attention_heads != 0 and not hasattr(config, "embedding_size"): raise ValueError( f"The hidden size ({config.hidden_size}) is not a multiple of the number of attention " f"heads ({config.num_attention_heads}" ) self.num_attention_heads = config.num_attention_heads self.hidden_size = config.hidden_size self.attention_head_size = config.hidden_size // config.num_attention_heads self.all_head_size = self.num_attention_heads * self.attention_head_size self.query = nn.Linear(config.hidden_size, self.all_head_size) self.key = nn.Linear(config.hidden_size, self.all_head_size) self.value = nn.Linear(config.hidden_size, self.all_head_size) self.attention_dropout = nn.Dropout(config.attention_probs_dropout_prob) self.output_dropout = nn.Dropout(config.hidden_dropout_prob) self.dense = nn.Linear(config.hidden_size, config.hidden_size) self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) self.pruned_heads = set() self.position_embedding_type = getattr(config, "position_embedding_type", "absolute") if self.position_embedding_type == "relative_key" or self.position_embedding_type == "relative_key_query": self.max_position_embeddings = config.max_position_embeddings self.distance_embedding = nn.Embedding(2 * config.max_position_embeddings - 1, self.attention_head_size) # Copied from transformers.models.bert.modeling_bert.BertSelfAttention.transpose_for_scores def transpose_for_scores(self, x): new_x_shape = x.size()[:-1] + (self.num_attention_heads, self.attention_head_size) x = x.view(*new_x_shape) return x.permute(0, 2, 1, 3) def prune_heads(self, heads): if len(heads) == 0: return heads, index = find_pruneable_heads_and_indices( heads, self.num_attention_heads, self.attention_head_size, self.pruned_heads ) # Prune linear layers self.query = prune_linear_layer(self.query, index) self.key = prune_linear_layer(self.key, index) self.value = prune_linear_layer(self.value, index) self.dense = prune_linear_layer(self.dense, index, dim=1) # Update hyper params and store pruned heads self.num_attention_heads = self.num_attention_heads - len(heads) self.all_head_size = self.attention_head_size * self.num_attention_heads self.pruned_heads = self.pruned_heads.union(heads) def forward(self, hidden_states, attention_mask=None, head_mask=None, output_attentions=False): mixed_query_layer = self.query(hidden_states) mixed_key_layer = self.key(hidden_states) mixed_value_layer = self.value(hidden_states) query_layer = self.transpose_for_scores(mixed_query_layer) key_layer = self.transpose_for_scores(mixed_key_layer) value_layer = self.transpose_for_scores(mixed_value_layer) # Take the dot product between "query" and "key" to get the raw attention scores. attention_scores = torch.matmul(query_layer, key_layer.transpose(-1, -2)) attention_scores = attention_scores / math.sqrt(self.attention_head_size) if attention_mask is not None: # Apply the attention mask is (precomputed for all layers in BertModel forward() function) attention_scores = attention_scores + attention_mask if self.position_embedding_type == "relative_key" or self.position_embedding_type == "relative_key_query": seq_length = hidden_states.size()[1] position_ids_l = torch.arange(seq_length, dtype=torch.long, device=hidden_states.device).view(-1, 1) position_ids_r = torch.arange(seq_length, dtype=torch.long, device=hidden_states.device).view(1, -1) distance = position_ids_l - position_ids_r positional_embedding = self.distance_embedding(distance + self.max_position_embeddings - 1) positional_embedding = positional_embedding.to(dtype=query_layer.dtype) # fp16 compatibility if self.position_embedding_type == "relative_key": relative_position_scores = torch.einsum("bhld,lrd->bhlr", query_layer, positional_embedding) attention_scores = attention_scores + relative_position_scores elif self.position_embedding_type == "relative_key_query": relative_position_scores_query = torch.einsum("bhld,lrd->bhlr", query_layer, positional_embedding) relative_position_scores_key = torch.einsum("bhrd,lrd->bhlr", key_layer, positional_embedding) attention_scores = attention_scores + relative_position_scores_query + relative_position_scores_key # Normalize the attention scores to probabilities. attention_probs = nn.Softmax(dim=-1)(attention_scores) # This is actually dropping out entire tokens to attend to, which might # seem a bit unusual, but is taken from the original Transformer paper. attention_probs = self.attention_dropout(attention_probs) # Mask heads if we want to if head_mask is not None: attention_probs = attention_probs * head_mask context_layer = torch.matmul(attention_probs, value_layer) context_layer = context_layer.transpose(2, 1).flatten(2) projected_context_layer = self.dense(context_layer) projected_context_layer_dropout = self.output_dropout(projected_context_layer) layernormed_context_layer = self.LayerNorm(hidden_states + projected_context_layer_dropout) return (layernormed_context_layer, attention_probs) if output_attentions else (layernormed_context_layer,) class AlbertLayer(nn.Module): def __init__(self, config): super().__init__() self.config = config self.chunk_size_feed_forward = config.chunk_size_feed_forward self.seq_len_dim = 1 self.full_layer_layer_norm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) self.attention = AlbertAttention(config) self.ffn = nn.Linear(config.hidden_size, config.intermediate_size) self.ffn_output = nn.Linear(config.intermediate_size, config.hidden_size) self.activation = ACT2FN[config.hidden_act] self.dropout = nn.Dropout(config.hidden_dropout_prob) def forward( self, hidden_states, attention_mask=None, head_mask=None, output_attentions=False, output_hidden_states=False ): attention_output = self.attention(hidden_states, attention_mask, head_mask, output_attentions) ffn_output = apply_chunking_to_forward( self.ff_chunk, self.chunk_size_feed_forward, self.seq_len_dim, attention_output[0], ) hidden_states = self.full_layer_layer_norm(ffn_output + attention_output[0]) return (hidden_states,) + attention_output[1:] # add attentions if we output them def ff_chunk(self, attention_output): ffn_output = self.ffn(attention_output) ffn_output = self.activation(ffn_output) ffn_output = self.ffn_output(ffn_output) return ffn_output class AlbertLayerGroup(nn.Module): def __init__(self, config): super().__init__() self.albert_layers = nn.ModuleList([AlbertLayer(config) for _ in range(config.inner_group_num)]) def forward( self, hidden_states, attention_mask=None, head_mask=None, output_attentions=False, output_hidden_states=False ): layer_hidden_states = () layer_attentions = () for layer_index, albert_layer in enumerate(self.albert_layers): layer_output = albert_layer(hidden_states, attention_mask, head_mask[layer_index], output_attentions) hidden_states = layer_output[0] if output_attentions: layer_attentions = layer_attentions + (layer_output[1],) if output_hidden_states: layer_hidden_states = layer_hidden_states + (hidden_states,) outputs = (hidden_states,) if output_hidden_states: outputs = outputs + (layer_hidden_states,) if output_attentions: outputs = outputs + (layer_attentions,) return outputs # last-layer hidden state, (layer hidden states), (layer attentions) class AlbertTransformer(nn.Module): def __init__(self, config): super().__init__() self.config = config self.embedding_hidden_mapping_in = nn.Linear(config.embedding_size, config.hidden_size) self.albert_layer_groups = nn.ModuleList([AlbertLayerGroup(config) for _ in range(config.num_hidden_groups)]) def forward( self, hidden_states, attention_mask=None, head_mask=None, output_attentions=False, output_hidden_states=False, return_dict=True, ): hidden_states = self.embedding_hidden_mapping_in(hidden_states) all_hidden_states = (hidden_states,) if output_hidden_states else None all_attentions = () if output_attentions else None head_mask = [None] * self.config.num_hidden_layers if head_mask is None else head_mask for i in range(self.config.num_hidden_layers): # Number of layers in a hidden group layers_per_group = int(self.config.num_hidden_layers / self.config.num_hidden_groups) # Index of the hidden group group_idx = int(i / (self.config.num_hidden_layers / self.config.num_hidden_groups)) layer_group_output = self.albert_layer_groups[group_idx]( hidden_states, attention_mask, head_mask[group_idx * layers_per_group : (group_idx + 1) * layers_per_group], output_attentions, output_hidden_states, ) hidden_states = layer_group_output[0] if output_attentions: all_attentions = all_attentions + layer_group_output[-1] if output_hidden_states: all_hidden_states = all_hidden_states + (hidden_states,) if not return_dict: return tuple(v for v in [hidden_states, all_hidden_states, all_attentions] if v is not None) return BaseModelOutput( last_hidden_state=hidden_states, hidden_states=all_hidden_states, attentions=all_attentions ) class AlbertPreTrainedModel(PreTrainedModel): """ An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained models. """ config_class = AlbertConfig load_tf_weights = load_tf_weights_in_albert base_model_prefix = "albert" _keys_to_ignore_on_load_missing = [r"position_ids"] def _init_weights(self, module): """Initialize the weights.""" if isinstance(module, nn.Linear): # Slightly different from the TF version which uses truncated_normal for initialization # cf https://github.com/pytorch/pytorch/pull/5617 module.weight.data.normal_(mean=0.0, std=self.config.initializer_range) if module.bias is not None: module.bias.data.zero_() elif isinstance(module, nn.Embedding): module.weight.data.normal_(mean=0.0, std=self.config.initializer_range) if module.padding_idx is not None: module.weight.data[module.padding_idx].zero_() elif isinstance(module, nn.LayerNorm): module.bias.data.zero_() module.weight.data.fill_(1.0) @dataclass class AlbertForPreTrainingOutput(ModelOutput): """ Output type of :class:`~transformers.AlbertForPreTraining`. Args: loss (`optional`, returned when ``labels`` is provided, ``torch.FloatTensor`` of shape :obj:`(1,)`): Total loss as the sum of the masked language modeling loss and the next sequence prediction (classification) loss. prediction_logits (:obj:`torch.FloatTensor` of shape :obj:`(batch_size, sequence_length, config.vocab_size)`): Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax). sop_logits (:obj:`torch.FloatTensor` of shape :obj:`(batch_size, 2)`): Prediction scores of the next sequence prediction (classification) head (scores of True/False continuation before SoftMax). hidden_states (:obj:`tuple(torch.FloatTensor)`, `optional`, returned when ``output_hidden_states=True`` is passed or when ``config.output_hidden_states=True``): Tuple of :obj:`torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of shape :obj:`(batch_size, sequence_length, hidden_size)`. Hidden-states of the model at the output of each layer plus the initial embedding outputs. attentions (:obj:`tuple(torch.FloatTensor)`, `optional`, returned when ``output_attentions=True`` is passed or when ``config.output_attentions=True``): Tuple of :obj:`torch.FloatTensor` (one for each layer) of shape :obj:`(batch_size, num_heads, sequence_length, sequence_length)`. Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads. """ loss: Optional[torch.FloatTensor] = None prediction_logits: torch.FloatTensor = None sop_logits: torch.FloatTensor = None hidden_states: Optional[Tuple[torch.FloatTensor]] = None attentions: Optional[Tuple[torch.FloatTensor]] = None ALBERT_START_DOCSTRING = r""" This model inherits from :class:`~transformers.PreTrainedModel`. Check the superclass documentation for the generic methods the library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads etc.) This model is also a PyTorch `torch.nn.Module `__ subclass. Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and behavior. Args: config (:class:`~transformers.AlbertConfig`): Model configuration class with all the parameters of the model. Initializing with a config file does not load the weights associated with the model, only the configuration. Check out the :meth:`~transformers.PreTrainedModel.from_pretrained` method to load the model weights. """ ALBERT_INPUTS_DOCSTRING = r""" Args: input_ids (:obj:`torch.LongTensor` of shape :obj:`({0})`): Indices of input sequence tokens in the vocabulary. Indices can be obtained using :class:`~transformers.AlbertTokenizer`. See :meth:`transformers.PreTrainedTokenizer.__call__` and :meth:`transformers.PreTrainedTokenizer.encode` for details. `What are input IDs? <../glossary.html#input-ids>`__ attention_mask (:obj:`torch.FloatTensor` of shape :obj:`({0})`, `optional`): Mask to avoid performing attention on padding token indices. Mask values selected in ``[0, 1]``: - 1 for tokens that are **not masked**, - 0 for tokens that are **masked**. `What are attention masks? <../glossary.html#attention-mask>`__ token_type_ids (:obj:`torch.LongTensor` of shape :obj:`({0})`, `optional`): Segment token indices to indicate first and second portions of the inputs. Indices are selected in ``[0, 1]``: - 0 corresponds to a `sentence A` token, - 1 corresponds to a `sentence B` token. `What are token type IDs? <../glossary.html#token-type-ids>`_ position_ids (:obj:`torch.LongTensor` of shape :obj:`({0})`, `optional`): Indices of positions of each input sequence tokens in the position embeddings. Selected in the range ``[0, config.max_position_embeddings - 1]``. `What are position IDs? <../glossary.html#position-ids>`_ head_mask (:obj:`torch.FloatTensor` of shape :obj:`(num_heads,)` or :obj:`(num_layers, num_heads)`, `optional`): Mask to nullify selected heads of the self-attention modules. Mask values selected in ``[0, 1]``: - 1 indicates the head is **not masked**, - 0 indicates the head is **masked**. inputs_embeds (:obj:`torch.FloatTensor` of shape :obj:`({0}, hidden_size)`, `optional`): Optionally, instead of passing :obj:`input_ids` you can choose to directly pass an embedded representation. This is useful if you want more control over how to convert :obj:`input_ids` indices into associated vectors than the model's internal embedding lookup matrix. output_attentions (:obj:`bool`, `optional`): Whether or not to return the attentions tensors of all attention layers. See ``attentions`` under returned tensors for more detail. output_hidden_states (:obj:`bool`, `optional`): Whether or not to return the hidden states of all layers. See ``hidden_states`` under returned tensors for more detail. return_dict (:obj:`bool`, `optional`): Whether or not to return a :class:`~transformers.file_utils.ModelOutput` instead of a plain tuple. """ @add_start_docstrings( "The bare ALBERT Model transformer outputting raw hidden-states without any specific head on top.", ALBERT_START_DOCSTRING, ) class AlbertModel(AlbertPreTrainedModel): config_class = AlbertConfig base_model_prefix = "albert" def __init__(self, config, add_pooling_layer=True): super().__init__(config) self.config = config self.embeddings = AlbertEmbeddings(config) self.encoder = AlbertTransformer(config) if add_pooling_layer: self.pooler = nn.Linear(config.hidden_size, config.hidden_size) self.pooler_activation = nn.Tanh() else: self.pooler = None self.pooler_activation = None self.init_weights() def get_input_embeddings(self): return self.embeddings.word_embeddings def set_input_embeddings(self, value): self.embeddings.word_embeddings = value def _prune_heads(self, heads_to_prune): """ Prunes heads of the model. heads_to_prune: dict of {layer_num: list of heads to prune in this layer} ALBERT has a different architecture in that its layers are shared across groups, which then has inner groups. If an ALBERT model has 12 hidden layers and 2 hidden groups, with two inner groups, there is a total of 4 different layers. These layers are flattened: the indices [0,1] correspond to the two inner groups of the first hidden layer, while [2,3] correspond to the two inner groups of the second hidden layer. Any layer with in index other than [0,1,2,3] will result in an error. See base class PreTrainedModel for more information about head pruning """ for layer, heads in heads_to_prune.items(): group_idx = int(layer / self.config.inner_group_num) inner_group_idx = int(layer - group_idx * self.config.inner_group_num) self.encoder.albert_layer_groups[group_idx].albert_layers[inner_group_idx].attention.prune_heads(heads) @add_start_docstrings_to_model_forward(ALBERT_INPUTS_DOCSTRING.format("batch_size, sequence_length")) @add_code_sample_docstrings( processor_class=_TOKENIZER_FOR_DOC, checkpoint=_CHECKPOINT_FOR_DOC, output_type=BaseModelOutputWithPooling, config_class=_CONFIG_FOR_DOC, ) def forward( self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions output_hidden_states = ( output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states ) return_dict = return_dict if return_dict is not None else self.config.use_return_dict if input_ids is not None and inputs_embeds is not None: raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time") elif input_ids is not None: input_shape = input_ids.size() elif inputs_embeds is not None: input_shape = inputs_embeds.size()[:-1] else: raise ValueError("You have to specify either input_ids or inputs_embeds") batch_size, seq_length = input_shape device = input_ids.device if input_ids is not None else inputs_embeds.device if attention_mask is None: attention_mask = torch.ones(input_shape, device=device) if token_type_ids is None: if hasattr(self.embeddings, "token_type_ids"): buffered_token_type_ids = self.embeddings.token_type_ids[:, :seq_length] buffered_token_type_ids_expanded = buffered_token_type_ids.expand(batch_size, seq_length) token_type_ids = buffered_token_type_ids_expanded else: token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=device) # extended_attention_mask = attention_mask.unsqueeze(1).unsqueeze(2) # extended_attention_mask = attention_mask[:, None, :, :] extended_attention_mask = extended_attention_mask.to(dtype=self.dtype) # fp16 compatibility extended_attention_mask = (1.0 - extended_attention_mask) * -10000.0 head_mask = self.get_head_mask(head_mask, self.config.num_hidden_layers) embedding_output = self.embeddings( input_ids, position_ids=position_ids, token_type_ids=token_type_ids, inputs_embeds=inputs_embeds ) encoder_outputs = self.encoder( embedding_output, extended_attention_mask, head_mask=head_mask, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_output = encoder_outputs[0] pooled_output = self.pooler_activation(self.pooler(sequence_output[:, 0])) if self.pooler is not None else None if not return_dict: return (sequence_output, pooled_output) + encoder_outputs[1:] return BaseModelOutputWithPooling( last_hidden_state=sequence_output, pooler_output=pooled_output, hidden_states=encoder_outputs.hidden_states, attentions=encoder_outputs.attentions, ) @add_start_docstrings( """ Albert Model with two heads on top as done during the pretraining: a `masked language modeling` head and a `sentence order prediction (classification)` head. """, ALBERT_START_DOCSTRING, ) class AlbertForPreTraining(AlbertPreTrainedModel): def __init__(self, config): super().__init__(config) self.albert = AlbertModel(config) self.predictions = AlbertMLMHead(config) self.sop_classifier = AlbertSOPHead(config) self.init_weights() def get_output_embeddings(self): return self.predictions.decoder def set_output_embeddings(self, new_embeddings): self.predictions.decoder = new_embeddings def get_input_embeddings(self): return self.albert.embeddings.word_embeddings @add_start_docstrings_to_model_forward(ALBERT_INPUTS_DOCSTRING.format("batch_size, sequence_length")) @replace_return_docstrings(output_type=AlbertForPreTrainingOutput, config_class=_CONFIG_FOR_DOC) def forward( self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, labels=None, sentence_order_label=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): r""" labels (``torch.LongTensor`` of shape ``(batch_size, sequence_length)``, `optional`): Labels for computing the masked language modeling loss. Indices should be in ``[-100, 0, ..., config.vocab_size]`` (see ``input_ids`` docstring) Tokens with indices set to ``-100`` are ignored (masked), the loss is only computed for the tokens with labels in ``[0, ..., config.vocab_size]`` sentence_order_label (``torch.LongTensor`` of shape ``(batch_size,)``, `optional`): Labels for computing the next sequence prediction (classification) loss. Input should be a sequence pair (see :obj:`input_ids` docstring) Indices should be in ``[0, 1]``. ``0`` indicates original order (sequence A, then sequence B), ``1`` indicates switched order (sequence B, then sequence A). Returns: Example:: >>> from transformers import AlbertTokenizer, AlbertForPreTraining >>> import torch >>> tokenizer = AlbertTokenizer.from_pretrained('albert-base-v2') >>> model = AlbertForPreTraining.from_pretrained('albert-base-v2') >>> input_ids = torch.tensor(tokenizer.encode("Hello, my dog is cute", add_special_tokens=True)).unsqueeze(0) # Batch size 1 >>> outputs = model(input_ids) >>> prediction_logits = outputs.prediction_logits >>> sop_logits = outputs.sop_logits """ return_dict = return_dict if return_dict is not None else self.config.use_return_dict outputs = self.albert( input_ids, attention_mask=attention_mask, token_type_ids=token_type_ids, position_ids=position_ids, head_mask=head_mask, inputs_embeds=inputs_embeds, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_output, pooled_output = outputs[:2] prediction_scores = self.predictions(sequence_output) sop_scores = self.sop_classifier(pooled_output) total_loss = None if labels is not None and sentence_order_label is not None: loss_fct = CrossEntropyLoss() masked_lm_loss = loss_fct(prediction_scores.view(-1, self.config.vocab_size), labels.view(-1)) sentence_order_loss = loss_fct(sop_scores.view(-1, 2), sentence_order_label.view(-1)) total_loss = masked_lm_loss + sentence_order_loss if not return_dict: output = (prediction_scores, sop_scores) + outputs[2:] return ((total_loss,) + output) if total_loss is not None else output return AlbertForPreTrainingOutput( loss=total_loss, prediction_logits=prediction_scores, sop_logits=sop_scores, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) class AlbertMLMHead(nn.Module): def __init__(self, config): super().__init__() self.LayerNorm = nn.LayerNorm(config.embedding_size) self.bias = nn.Parameter(torch.zeros(config.vocab_size)) self.dense = nn.Linear(config.hidden_size, config.embedding_size) self.decoder = nn.Linear(config.embedding_size, config.vocab_size) self.activation = ACT2FN[config.hidden_act] self.decoder.bias = self.bias def forward(self, hidden_states): hidden_states = self.dense(hidden_states) hidden_states = self.activation(hidden_states) hidden_states = self.LayerNorm(hidden_states) hidden_states = self.decoder(hidden_states) prediction_scores = hidden_states return prediction_scores def _tie_weights(self): # To tie those two weights if they get disconnected (on TPU or when the bias is resized) self.bias = self.decoder.bias class AlbertSOPHead(nn.Module): def __init__(self, config): super().__init__() self.dropout = nn.Dropout(config.classifier_dropout_prob) self.classifier = nn.Linear(config.hidden_size, config.num_labels) def forward(self, pooled_output): dropout_pooled_output = self.dropout(pooled_output) logits = self.classifier(dropout_pooled_output) return logits @add_start_docstrings( "Albert Model with a `language modeling` head on top.", ALBERT_START_DOCSTRING, ) class AlbertForMaskedLM(AlbertPreTrainedModel): _keys_to_ignore_on_load_unexpected = [r"pooler"] def __init__(self, config): super().__init__(config) self.albert = AlbertModel(config, add_pooling_layer=False) self.predictions = AlbertMLMHead(config) self.init_weights() def get_output_embeddings(self): return self.predictions.decoder def set_output_embeddings(self, new_embeddings): self.predictions.decoder = new_embeddings def get_input_embeddings(self): return self.albert.embeddings.word_embeddings @add_start_docstrings_to_model_forward(ALBERT_INPUTS_DOCSTRING.format("batch_size, sequence_length")) @add_code_sample_docstrings( processor_class=_TOKENIZER_FOR_DOC, checkpoint=_CHECKPOINT_FOR_DOC, output_type=MaskedLMOutput, config_class=_CONFIG_FOR_DOC, ) def forward( self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, labels=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): r""" labels (:obj:`torch.LongTensor` of shape :obj:`(batch_size, sequence_length)`, `optional`): Labels for computing the masked language modeling loss. Indices should be in ``[-100, 0, ..., config.vocab_size]`` (see ``input_ids`` docstring) Tokens with indices set to ``-100`` are ignored (masked), the loss is only computed for the tokens with labels in ``[0, ..., config.vocab_size]`` """ return_dict = return_dict if return_dict is not None else self.config.use_return_dict outputs = self.albert( input_ids=input_ids, attention_mask=attention_mask, token_type_ids=token_type_ids, position_ids=position_ids, head_mask=head_mask, inputs_embeds=inputs_embeds, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_outputs = outputs[0] prediction_scores = self.predictions(sequence_outputs) masked_lm_loss = None if labels is not None: loss_fct = CrossEntropyLoss() masked_lm_loss = loss_fct(prediction_scores.view(-1, self.config.vocab_size), labels.view(-1)) if not return_dict: output = (prediction_scores,) + outputs[2:] return ((masked_lm_loss,) + output) if masked_lm_loss is not None else output return MaskedLMOutput( loss=masked_lm_loss, logits=prediction_scores, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) @add_start_docstrings( """ Albert Model transformer with a sequence classification/regression head on top (a linear layer on top of the pooled output) e.g. for GLUE tasks. """, ALBERT_START_DOCSTRING, ) class AlbertForSequenceClassification(AlbertPreTrainedModel): def __init__(self, config): super().__init__(config) self.num_labels = config.num_labels self.config = config self.albert = AlbertModel(config) self.dropout = nn.Dropout(config.classifier_dropout_prob) self.classifier = nn.Linear(config.hidden_size, self.config.num_labels) self.init_weights() @add_start_docstrings_to_model_forward(ALBERT_INPUTS_DOCSTRING.format("batch_size, sequence_length")) @add_code_sample_docstrings( processor_class=_TOKENIZER_FOR_DOC, checkpoint=_CHECKPOINT_FOR_DOC, output_type=SequenceClassifierOutput, config_class=_CONFIG_FOR_DOC, ) def forward( self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, labels=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): r""" labels (:obj:`torch.LongTensor` of shape :obj:`(batch_size,)`, `optional`): Labels for computing the sequence classification/regression loss. Indices should be in ``[0, ..., config.num_labels - 1]``. If ``config.num_labels == 1`` a regression loss is computed (Mean-Square loss), If ``config.num_labels > 1`` a classification loss is computed (Cross-Entropy). """ return_dict = return_dict if return_dict is not None else self.config.use_return_dict outputs = self.albert( input_ids=input_ids, attention_mask=attention_mask, token_type_ids=token_type_ids, position_ids=position_ids, head_mask=head_mask, inputs_embeds=inputs_embeds, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) pooled_output = outputs[1] pooled_output = self.dropout(pooled_output) logits = self.classifier(pooled_output) loss = None if labels is not None: if self.config.problem_type is None: if self.num_labels == 1: self.config.problem_type = "regression" elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int): self.config.problem_type = "single_label_classification" else: self.config.problem_type = "multi_label_classification" if self.config.problem_type == "regression": loss_fct = MSELoss() if self.num_labels == 1: loss = loss_fct(logits.squeeze(), labels.squeeze()) else: loss = loss_fct(logits, labels) elif self.config.problem_type == "single_label_classification": loss_fct = CrossEntropyLoss() loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1)) elif self.config.problem_type == "multi_label_classification": loss_fct = BCEWithLogitsLoss() loss = loss_fct(logits, labels) if not return_dict: output = (logits,) + outputs[2:] return ((loss,) + output) if loss is not None else output return SequenceClassifierOutput( loss=loss, logits=logits, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) @add_start_docstrings( """ Albert Model with a token classification head on top (a linear layer on top of the hidden-states output) e.g. for Named-Entity-Recognition (NER) tasks. """, ALBERT_START_DOCSTRING, ) class AlbertForTokenClassification(AlbertPreTrainedModel): _keys_to_ignore_on_load_unexpected = [r"pooler"] def __init__(self, config): super().__init__(config) self.num_labels = config.num_labels self.albert = AlbertModel(config, add_pooling_layer=False) classifier_dropout_prob = ( config.classifier_dropout_prob if config.classifier_dropout_prob is not None else config.hidden_dropout_prob ) self.dropout = nn.Dropout(classifier_dropout_prob) self.classifier = nn.Linear(config.hidden_size, self.config.num_labels) self.init_weights() @add_start_docstrings_to_model_forward(ALBERT_INPUTS_DOCSTRING.format("batch_size, sequence_length")) @add_code_sample_docstrings( processor_class=_TOKENIZER_FOR_DOC, checkpoint=_CHECKPOINT_FOR_DOC, output_type=TokenClassifierOutput, config_class=_CONFIG_FOR_DOC, ) def forward( self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, labels=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): r""" labels (:obj:`torch.LongTensor` of shape :obj:`(batch_size, sequence_length)`, `optional`): Labels for computing the token classification loss. Indices should be in ``[0, ..., config.num_labels - 1]``. """ return_dict = return_dict if return_dict is not None else self.config.use_return_dict outputs = self.albert( input_ids, attention_mask=attention_mask, token_type_ids=token_type_ids, position_ids=position_ids, head_mask=head_mask, inputs_embeds=inputs_embeds, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_output = outputs[0] sequence_output = self.dropout(sequence_output) logits = self.classifier(sequence_output) loss = None if labels is not None: loss_fct = CrossEntropyLoss() # Only keep active parts of the loss if attention_mask is not None: active_loss = attention_mask.view(-1) == 1 active_logits = logits.view(-1, self.num_labels) active_labels = torch.where( active_loss, labels.view(-1), torch.tensor(loss_fct.ignore_index).type_as(labels) ) loss = loss_fct(active_logits, active_labels) else: loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1)) if not return_dict: output = (logits,) + outputs[2:] return ((loss,) + output) if loss is not None else output return TokenClassifierOutput( loss=loss, logits=logits, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) @add_start_docstrings( """ Albert Model with a span classification head on top for extractive question-answering tasks like SQuAD (a linear layers on top of the hidden-states output to compute `span start logits` and `span end logits`). """, ALBERT_START_DOCSTRING, ) class AlbertForQuestionAnswering(AlbertPreTrainedModel): _keys_to_ignore_on_load_unexpected = [r"pooler"] def __init__(self, config): super().__init__(config) self.num_labels = config.num_labels self.albert = AlbertModel(config, add_pooling_layer=False) self.qa_outputs = nn.Linear(config.hidden_size, config.num_labels) self.init_weights() @add_start_docstrings_to_model_forward(ALBERT_INPUTS_DOCSTRING.format("batch_size, sequence_length")) @add_code_sample_docstrings( processor_class=_TOKENIZER_FOR_DOC, checkpoint=_CHECKPOINT_FOR_DOC, output_type=QuestionAnsweringModelOutput, config_class=_CONFIG_FOR_DOC, ) def forward( self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, start_positions=None, end_positions=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): r""" start_positions (:obj:`torch.LongTensor` of shape :obj:`(batch_size,)`, `optional`): Labels for position (index) of the start of the labelled span for computing the token classification loss. Positions are clamped to the length of the sequence (:obj:`sequence_length`). Position outside of the sequence are not taken into account for computing the loss. end_positions (:obj:`torch.LongTensor` of shape :obj:`(batch_size,)`, `optional`): Labels for position (index) of the end of the labelled span for computing the token classification loss. Positions are clamped to the length of the sequence (:obj:`sequence_length`). Position outside of the sequence are not taken into account for computing the loss. """ return_dict = return_dict if return_dict is not None else self.config.use_return_dict outputs = self.albert( input_ids=input_ids, attention_mask=attention_mask, token_type_ids=token_type_ids, position_ids=position_ids, head_mask=head_mask, inputs_embeds=inputs_embeds, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_output = outputs[0] logits = self.qa_outputs(sequence_output) start_logits, end_logits = logits.split(1, dim=-1) start_logits = start_logits.squeeze(-1).contiguous() end_logits = end_logits.squeeze(-1).contiguous() total_loss = None if start_positions is not None and end_positions is not None: # If we are on multi-GPU, split add a dimension if len(start_positions.size()) > 1: start_positions = start_positions.squeeze(-1) if len(end_positions.size()) > 1: end_positions = end_positions.squeeze(-1) # sometimes the start/end positions are outside our model inputs, we ignore these terms ignored_index = start_logits.size(1) start_positions = start_positions.clamp(0, ignored_index) end_positions = end_positions.clamp(0, ignored_index) loss_fct = CrossEntropyLoss(ignore_index=ignored_index) start_loss = loss_fct(start_logits, start_positions) end_loss = loss_fct(end_logits, end_positions) total_loss = (start_loss + end_loss) / 2 if not return_dict: output = (start_logits, end_logits) + outputs[2:] return ((total_loss,) + output) if total_loss is not None else output return QuestionAnsweringModelOutput( loss=total_loss, start_logits=start_logits, end_logits=end_logits, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) @add_start_docstrings( """ Albert Model with a multiple choice classification head on top (a linear layer on top of the pooled output and a softmax) e.g. for RocStories/SWAG tasks. """, ALBERT_START_DOCSTRING, ) class AlbertForMultipleChoice(AlbertPreTrainedModel): def __init__(self, config): super().__init__(config) self.albert = AlbertModel(config) self.dropout = nn.Dropout(config.classifier_dropout_prob) self.classifier = nn.Linear(config.hidden_size, 1) self.init_weights() @add_start_docstrings_to_model_forward(ALBERT_INPUTS_DOCSTRING.format("batch_size, num_choices, sequence_length")) @add_code_sample_docstrings( processor_class=_TOKENIZER_FOR_DOC, checkpoint=_CHECKPOINT_FOR_DOC, output_type=MultipleChoiceModelOutput, config_class=_CONFIG_FOR_DOC, ) def forward( self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, labels=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): r""" labels (:obj:`torch.LongTensor` of shape :obj:`(batch_size,)`, `optional`): Labels for computing the multiple choice classification loss. Indices should be in ``[0, ..., num_choices-1]`` where `num_choices` is the size of the second dimension of the input tensors. (see `input_ids` above) """ return_dict = return_dict if return_dict is not None else self.config.use_return_dict num_choices = input_ids.shape[1] if input_ids is not None else inputs_embeds.shape[1] input_ids = input_ids.view(-1, input_ids.size(-1)) if input_ids is not None else None attention_mask = attention_mask.view(-1, attention_mask.size(-1)) if attention_mask is not None else None token_type_ids = token_type_ids.view(-1, token_type_ids.size(-1)) if token_type_ids is not None else None position_ids = position_ids.view(-1, position_ids.size(-1)) if position_ids is not None else None inputs_embeds = ( inputs_embeds.view(-1, inputs_embeds.size(-2), inputs_embeds.size(-1)) if inputs_embeds is not None else None ) outputs = self.albert( input_ids, attention_mask=attention_mask, token_type_ids=token_type_ids, position_ids=position_ids, head_mask=head_mask, inputs_embeds=inputs_embeds, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) pooled_output = outputs[1] pooled_output = self.dropout(pooled_output) logits = self.classifier(pooled_output) reshaped_logits = logits.view(-1, num_choices) loss = None if labels is not None: loss_fct = CrossEntropyLoss() loss = loss_fct(reshaped_logits, labels) if not return_dict: output = (reshaped_logits,) + outputs[2:] return ((loss,) + output) if loss is not None else output return MultipleChoiceModelOutput( loss=loss, logits=reshaped_logits, hidden_states=outputs.hidden_states, attentions=outputs.attentions, )