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- # Copyright (c) Alibaba, Inc. and its affiliates.
- # Copyright 2018 The Google AI Language Team Authors and The HuggingFace Inc. team.
- # Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
- #
- # 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 BERT model. """
- import math
- import torch
- import torch.utils.checkpoint
- from packaging import version
- from torch import nn
- from transformers.activations import ACT2FN
- from transformers.modeling_utils import PreTrainedModel
- from modelscope.metainfo import Models
- from modelscope.models import Model, TorchModel
- from modelscope.models.builder import MODELS
- from modelscope.outputs import AttentionBackboneModelOutput
- from modelscope.utils.constant import Tasks
- from modelscope.utils.logger import get_logger
- from modelscope.utils.nlp.utils import parse_labels_in_order
- from modelscope.utils.torch_utils import (apply_chunking_to_forward,
- find_pruneable_heads_and_indices,
- prune_linear_layer)
- from .configuration import BertConfig
- logger = get_logger()
- _CONFIG_FOR_DOC = 'BertConfig'
- class BertEmbeddings(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.hidden_size,
- padding_idx=config.pad_token_id)
- self.position_embeddings = nn.Embedding(config.max_position_embeddings,
- config.hidden_size)
- self.token_type_embeddings = nn.Embedding(config.type_vocab_size,
- config.hidden_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.hidden_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.position_embedding_type = getattr(config,
- 'position_embedding_type',
- 'absolute')
- self.register_buffer(
- 'position_ids',
- torch.arange(config.max_position_embeddings).expand((1, -1)))
- 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),
- persistent=False,
- )
- 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 BertSelfAttention(nn.Module):
- def __init__(self, config, position_embedding_type=None):
- 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.attention_head_size = int(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.dropout = nn.Dropout(config.attention_probs_dropout_prob)
- self.position_embedding_type = position_embedding_type or 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)
- self.is_decoder = config.is_decoder
- 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 forward(
- self,
- hidden_states,
- attention_mask=None,
- head_mask=None,
- encoder_hidden_states=None,
- encoder_attention_mask=None,
- past_key_value=None,
- output_attentions=False,
- ):
- mixed_query_layer = self.query(hidden_states)
- # If this is instantiated as a cross-attention module, the keys
- # and values come from an encoder; the attention mask needs to be
- # such that the encoder's padding tokens are not attended to.
- is_cross_attention = encoder_hidden_states is not None
- if is_cross_attention and past_key_value is not None:
- # reuse k,v, cross_attentions
- key_layer = past_key_value[0]
- value_layer = past_key_value[1]
- attention_mask = encoder_attention_mask
- elif is_cross_attention:
- key_layer = self.transpose_for_scores(
- self.key(encoder_hidden_states))
- value_layer = self.transpose_for_scores(
- self.value(encoder_hidden_states))
- attention_mask = encoder_attention_mask
- elif past_key_value is not None:
- key_layer = self.transpose_for_scores(self.key(hidden_states))
- value_layer = self.transpose_for_scores(self.value(hidden_states))
- key_layer = torch.cat([past_key_value[0], key_layer], dim=2)
- value_layer = torch.cat([past_key_value[1], value_layer], dim=2)
- else:
- key_layer = self.transpose_for_scores(self.key(hidden_states))
- value_layer = self.transpose_for_scores(self.value(hidden_states))
- query_layer = self.transpose_for_scores(mixed_query_layer)
- if self.is_decoder:
- # if cross_attention save Tuple(torch.Tensor, torch.Tensor) of all
- # cross attention key/value_states. Further calls to cross_attention
- # layer can then reuse all cross-attention key/value_states (first
- # "if" case) if uni-directional self-attention (decoder) save
- # Tuple(torch.Tensor, torch.Tensor) of all previous decoder
- # key/value_states. Further calls to uni-directional self-attention
- # can concat previous decoder key/value_states to current projected
- # key/value_states (third "elif" case) if encoder bi-directional
- # self-attention `past_key_value` is always `None`
- past_key_value = (key_layer, 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))
- 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
- 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
- # Normalize the attention scores to probabilities.
- attention_probs = nn.functional.softmax(attention_scores, dim=-1)
- # 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.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.permute(0, 2, 1, 3).contiguous()
- new_context_layer_shape = context_layer.size()[:-2] + (
- self.all_head_size, )
- context_layer = context_layer.view(*new_context_layer_shape)
- outputs = (context_layer,
- attention_probs) if output_attentions else (context_layer, )
- if self.is_decoder:
- outputs = outputs + (past_key_value, )
- return outputs
- class BertSelfOutput(nn.Module):
- def __init__(self, config):
- super().__init__()
- self.dense = nn.Linear(config.hidden_size, config.hidden_size)
- self.LayerNorm = nn.LayerNorm(
- config.hidden_size, eps=config.layer_norm_eps)
- self.dropout = nn.Dropout(config.hidden_dropout_prob)
- def forward(self, hidden_states, input_tensor):
- hidden_states = self.dense(hidden_states)
- hidden_states = self.dropout(hidden_states)
- hidden_states = self.LayerNorm(hidden_states + input_tensor)
- return hidden_states
- class BertAttention(nn.Module):
- def __init__(self, config, position_embedding_type=None):
- super().__init__()
- self.self = BertSelfAttention(
- config, position_embedding_type=position_embedding_type)
- self.output = BertSelfOutput(config)
- self.pruned_heads = set()
- def prune_heads(self, heads):
- if len(heads) == 0:
- return
- heads, index = find_pruneable_heads_and_indices(
- heads, self.self.num_attention_heads,
- self.self.attention_head_size, self.pruned_heads)
- # Prune linear layers
- self.self.query = prune_linear_layer(self.self.query, index)
- self.self.key = prune_linear_layer(self.self.key, index)
- self.self.value = prune_linear_layer(self.self.value, index)
- self.output.dense = prune_linear_layer(self.output.dense, index, dim=1)
- # Update hyper params and store pruned heads
- self.self.num_attention_heads = self.self.num_attention_heads - len(
- heads)
- self.self.all_head_size = self.self.attention_head_size * self.self.num_attention_heads
- self.pruned_heads = self.pruned_heads.union(heads)
- def forward(
- self,
- hidden_states,
- attention_mask=None,
- head_mask=None,
- encoder_hidden_states=None,
- encoder_attention_mask=None,
- past_key_value=None,
- output_attentions=False,
- ):
- self_outputs = self.self(
- hidden_states,
- attention_mask,
- head_mask,
- encoder_hidden_states,
- encoder_attention_mask,
- past_key_value,
- output_attentions,
- )
- attention_output = self.output(self_outputs[0], hidden_states)
- outputs = (attention_output,
- ) + self_outputs[1:] # add attentions if we output them
- return outputs
- class BertIntermediate(nn.Module):
- def __init__(self, config):
- super().__init__()
- self.dense = nn.Linear(config.hidden_size, config.intermediate_size)
- if isinstance(config.hidden_act, str):
- self.intermediate_act_fn = ACT2FN[config.hidden_act]
- else:
- self.intermediate_act_fn = config.hidden_act
- def forward(self, hidden_states):
- hidden_states = self.dense(hidden_states)
- hidden_states = self.intermediate_act_fn(hidden_states)
- return hidden_states
- class BertOutput(nn.Module):
- def __init__(self, config):
- super().__init__()
- self.dense = nn.Linear(config.intermediate_size, config.hidden_size)
- self.LayerNorm = nn.LayerNorm(
- config.hidden_size, eps=config.layer_norm_eps)
- self.dropout = nn.Dropout(config.hidden_dropout_prob)
- def forward(self, hidden_states, input_tensor):
- hidden_states = self.dense(hidden_states)
- hidden_states = self.dropout(hidden_states)
- hidden_states = self.LayerNorm(hidden_states + input_tensor)
- return hidden_states
- class BertLayer(nn.Module):
- def __init__(self, config):
- super().__init__()
- self.chunk_size_feed_forward = config.chunk_size_feed_forward
- self.seq_len_dim = 1
- self.attention = BertAttention(config)
- self.is_decoder = config.is_decoder
- self.add_cross_attention = config.add_cross_attention
- if self.add_cross_attention:
- if not self.is_decoder:
- raise ValueError(
- f'{self} should be used as a decoder model if cross attention is added'
- )
- self.crossattention = BertAttention(
- config, position_embedding_type='absolute')
- self.intermediate = BertIntermediate(config)
- self.output = BertOutput(config)
- def forward(
- self,
- hidden_states,
- attention_mask=None,
- head_mask=None,
- encoder_hidden_states=None,
- encoder_attention_mask=None,
- past_key_value=None,
- output_attentions=False,
- ):
- # decoder uni-directional self-attention cached key/values tuple is at positions 1,2
- self_attn_past_key_value = past_key_value[:
- 2] if past_key_value is not None else None
- self_attention_outputs = self.attention(
- hidden_states,
- attention_mask,
- head_mask,
- output_attentions=output_attentions,
- past_key_value=self_attn_past_key_value,
- )
- attention_output = self_attention_outputs[0]
- # if decoder, the last output is tuple of self-attn cache
- if self.is_decoder:
- outputs = self_attention_outputs[1:-1]
- present_key_value = self_attention_outputs[-1]
- else:
- outputs = self_attention_outputs[
- 1:] # add self attentions if we output attention weights
- cross_attn_present_key_value = None
- if self.is_decoder and encoder_hidden_states is not None:
- if not hasattr(self, 'crossattention'):
- raise ValueError(
- f'If `encoder_hidden_states` are passed, {self} has to be instantiated '
- f'with cross-attention layers by setting `config.add_cross_attention=True`'
- )
- # cross_attn cached key/values tuple is at positions 3,4 of past_key_value tuple
- cross_attn_past_key_value = past_key_value[
- -2:] if past_key_value is not None else None
- cross_attention_outputs = self.crossattention(
- attention_output,
- attention_mask,
- head_mask,
- encoder_hidden_states,
- encoder_attention_mask,
- cross_attn_past_key_value,
- output_attentions,
- )
- attention_output = cross_attention_outputs[0]
- outputs = outputs + cross_attention_outputs[
- 1:-1] # add cross attentions if we output attention weights
- # add cross-attn cache to positions 3,4 of present_key_value tuple
- cross_attn_present_key_value = cross_attention_outputs[-1]
- present_key_value = present_key_value + cross_attn_present_key_value
- layer_output = apply_chunking_to_forward(self.feed_forward_chunk,
- self.chunk_size_feed_forward,
- self.seq_len_dim,
- attention_output)
- outputs = (layer_output, ) + outputs
- # if decoder, return the attn key/values as the last output
- if self.is_decoder:
- outputs = outputs + (present_key_value, )
- return outputs
- def feed_forward_chunk(self, attention_output):
- intermediate_output = self.intermediate(attention_output)
- layer_output = self.output(intermediate_output, attention_output)
- return layer_output
- class BertEncoder(nn.Module):
- def __init__(self, config):
- super().__init__()
- self.config = config
- self.layer = nn.ModuleList(
- [BertLayer(config) for _ in range(config.num_hidden_layers)])
- self.gradient_checkpointing = False
- def forward(
- self,
- hidden_states,
- attention_mask=None,
- head_mask=None,
- encoder_hidden_states=None,
- encoder_attention_mask=None,
- past_key_values=None,
- use_cache=None,
- output_attentions=False,
- output_hidden_states=False,
- return_dict=True,
- ):
- all_hidden_states = () if output_hidden_states else None
- all_self_attentions = () if output_attentions else None
- all_cross_attentions = (
- ) if output_attentions and self.config.add_cross_attention else None
- next_decoder_cache = () if use_cache else None
- for i, layer_module in enumerate(self.layer):
- if output_hidden_states:
- all_hidden_states = all_hidden_states + (hidden_states, )
- layer_head_mask = head_mask[i] if head_mask is not None else None
- past_key_value = past_key_values[
- i] if past_key_values is not None else None
- if self.gradient_checkpointing and self.training:
- if use_cache:
- logger.warning(
- '`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`...'
- )
- use_cache = False
- def create_custom_forward(module):
- def custom_forward(*inputs):
- return module(*inputs, past_key_value,
- output_attentions)
- return custom_forward
- layer_outputs = torch.utils.checkpoint.checkpoint(
- create_custom_forward(layer_module),
- hidden_states,
- attention_mask,
- layer_head_mask,
- encoder_hidden_states,
- encoder_attention_mask,
- )
- else:
- layer_outputs = layer_module(
- hidden_states,
- attention_mask,
- layer_head_mask,
- encoder_hidden_states,
- encoder_attention_mask,
- past_key_value,
- output_attentions,
- )
- hidden_states = layer_outputs[0]
- if use_cache:
- next_decoder_cache += (layer_outputs[-1], )
- if output_attentions:
- all_self_attentions = all_self_attentions + (
- layer_outputs[1], )
- if self.config.add_cross_attention:
- all_cross_attentions = all_cross_attentions + (
- layer_outputs[2], )
- if output_hidden_states:
- all_hidden_states = all_hidden_states + (hidden_states, )
- if not return_dict:
- return tuple(v for v in [
- hidden_states,
- next_decoder_cache,
- all_hidden_states,
- all_self_attentions,
- all_cross_attentions,
- ] if v is not None)
- return AttentionBackboneModelOutput(
- last_hidden_state=hidden_states,
- past_key_values=next_decoder_cache,
- hidden_states=all_hidden_states,
- attentions=all_self_attentions,
- cross_attentions=all_cross_attentions,
- )
- class BertPooler(nn.Module):
- def __init__(self, config):
- super().__init__()
- self.dense = nn.Linear(config.hidden_size, config.hidden_size)
- self.activation = nn.Tanh()
- def forward(self, hidden_states):
- # We "pool" the model by simply taking the hidden state corresponding
- # to the first token.
- first_token_tensor = hidden_states[:, 0]
- pooled_output = self.dense(first_token_tensor)
- pooled_output = self.activation(pooled_output)
- return pooled_output
- class BertPreTrainedModel(TorchModel, PreTrainedModel):
- """
- An abstract class to handle weights initialization and a simple interface
- for downloading and loading pretrained models.
- """
- config_class = BertConfig
- base_model_prefix = 'bert'
- supports_gradient_checkpointing = True
- _keys_to_ignore_on_load_missing = [r'position_ids']
- def __init__(self, config, **kwargs):
- super().__init__(config.name_or_path, **kwargs)
- super(Model, self).__init__(config)
- 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)
- def _set_gradient_checkpointing(self, module, value=False):
- if isinstance(module, BertEncoder):
- module.gradient_checkpointing = value
- @classmethod
- def _instantiate(cls, **kwargs):
- """Instantiate the model.
- Args:
- kwargs: Input args.
- model_dir: The model dir used to load the checkpoint and the label information.
- num_labels: An optional arg to tell the model how many classes to initialize.
- Method will call utils.parse_label_mapping if num_labels not supplied.
- If num_labels is not found, the model will use the default setting (2 classes).
- Returns:
- The loaded model, which is initialized by transformers.PreTrainedModel.from_pretrained
- """
- model_dir = kwargs.pop('model_dir', None)
- cfg = kwargs.pop('cfg', None)
- model_args = parse_labels_in_order(model_dir, cfg, **kwargs)
- if model_dir is None:
- config = BertConfig(**model_args)
- model = cls(config)
- else:
- model = super(Model, cls).from_pretrained(
- pretrained_model_name_or_path=model_dir, **model_args)
- model.model_dir = model_dir
- return model
- @MODELS.register_module(group_key=Tasks.backbone, module_name=Models.bert)
- class BertModel(BertPreTrainedModel):
- """The Bert Model transformer outputting raw hidden-states without any
- specific head on top.
- This model inherits from [`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](https://pytorch.org/docs/stable/nn.html#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.
- Parameters:
- config ([`BertConfig`]): 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
- [`~PreTrainedModel.from_pretrained`] method to load the model
- weights.
- The model can behave as an encoder (with only self-attention) as well as a
- decoder, in which case a layer of cross-attention is added between the
- self-attention layers, following the architecture described in [Attention is
- all you need](https://arxiv.org/abs/1706.03762) by Ashish Vaswani, Noam
- Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz
- Kaiser and Illia Polosukhin.
- To behave as an decoder the model needs to be initialized with the
- `is_decoder` argument of the configuration set to `True`. To be used in a
- Seq2Seq model, the model needs to initialized with both `is_decoder`
- argument and `add_cross_attention` set to `True`; an `encoder_hidden_states`
- is then expected as an input to the forward pass.
- """
- def __init__(self, config, add_pooling_layer=True):
- super().__init__(config)
- self.embeddings = BertEmbeddings(config)
- self.encoder = BertEncoder(config)
- self.pooler = BertPooler(config) if add_pooling_layer else None
- # Initialize weights and apply final processing
- self.post_init()
- @classmethod
- def _instantiate(cls, model_dir=None, add_pooling_layer=True, **config):
- config = BertConfig(**config)
- model = cls(config, add_pooling_layer)
- return model
- 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} See base
- class PreTrainedModel
- """
- for layer, heads in heads_to_prune.items():
- self.encoder.layer[layer].attention.prune_heads(heads)
- def forward(self,
- input_ids=None,
- attention_mask=None,
- token_type_ids=None,
- position_ids=None,
- head_mask=None,
- inputs_embeds=None,
- encoder_hidden_states=None,
- encoder_attention_mask=None,
- past_key_values=None,
- use_cache=None,
- output_attentions=None,
- output_hidden_states=None,
- return_dict=None,
- **kwargs) -> AttentionBackboneModelOutput:
- r"""
- Args:
- input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
- Indices of input sequence tokens in the vocabulary.
- Indices can be obtained using [`BertTokenizer`]. See
- [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`]
- for details.
- [What are input IDs?](../glossary#input-ids)
- attention_mask (`torch.FloatTensor` of shape `(batch_size, sequence_length)`, *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#attention-mask)
- token_type_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *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#token-type-ids)
- position_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *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#position-ids)
- head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(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 (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`,
- *optional*):
- Optionally, instead of passing `input_ids` you can choose to
- directly pass an embedded representation. This is useful if you want
- more control over how to convert `input_ids` indices into associated
- vectors than the model's internal embedding lookup matrix.
- output_attentions (`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 (`bool`, *optional*):
- Whether or not to return the hidden states of all layers. See
- `hidden_states` under returned tensors for more detail.
- return_dict (`bool`, *optional*):
- Whether or not to return a [`~file_utils.ModelOutput`] instead of a
- plain tuple.
- encoder_hidden_states (`torch.FloatTensor` of shape `(batch_size,
- sequence_length, hidden_size)`, *optional*):
- Sequence of hidden-states at the output of the last layer of the
- encoder. Used in the cross-attention if the model is configured as a
- decoder.
- encoder_attention_mask (`torch.FloatTensor` of shape `(batch_size,
- sequence_length)`, *optional*):
- Mask to avoid performing attention on the padding token indices of
- the encoder input. This mask is used in the cross-attention if the
- model is configured as a decoder. Mask values selected in `[0, 1]`:
- - 1 for tokens that are **not masked**,
- - 0 for tokens that are **masked**.
- past_key_values (`tuple(tuple(torch.FloatTensor))` of length
- `config.n_layers` with each tuple having 4 tensors of shape
- `(batch_size, num_heads, sequence_length - 1, embed_size_per_head)`):
- Contains precomputed key and value hidden states of the attention
- blocks. Can be used to speed up decoding.
- If `past_key_values` are used, the user can optionally input only
- the last `decoder_input_ids` (those that don't have their past key
- value states given to this model) of shape `(batch_size, 1)` instead
- of all `decoder_input_ids` of shape `(batch_size, sequence_length)`.
- use_cache (`bool`, *optional*):
- If set to `True`, `past_key_values` key value states are returned
- and can be used to speed up decoding (see `past_key_values`).
- Others (**kwargs)
- some additional parameters might passed in from upstream pipeline,
- which not influence the results.
- """
- 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 self.config.is_decoder:
- use_cache = use_cache if use_cache is not None else self.config.use_cache
- else:
- use_cache = False
- 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
- # past_key_values_length
- past_key_values_length = past_key_values[0][0].shape[
- 2] if past_key_values is not None else 0
- if attention_mask is None:
- attention_mask = torch.ones(
- ((batch_size, seq_length + past_key_values_length)),
- 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)
- # We can provide a self-attention mask of dimensions [batch_size, from_seq_length, to_seq_length]
- # ourselves in which case we just need to make it broadcastable to all heads.
- extended_attention_mask: torch.Tensor = self.get_extended_attention_mask(
- attention_mask, input_shape, device)
- # If a 2D or 3D attention mask is provided for the cross-attention
- # we need to make broadcastable to [batch_size, num_heads, seq_length, seq_length]
- if self.config.is_decoder and encoder_hidden_states is not None:
- encoder_batch_size, encoder_sequence_length, _ = encoder_hidden_states.size(
- )
- encoder_hidden_shape = (encoder_batch_size,
- encoder_sequence_length)
- if encoder_attention_mask is None:
- encoder_attention_mask = torch.ones(
- encoder_hidden_shape, device=device)
- encoder_extended_attention_mask = self.invert_attention_mask(
- encoder_attention_mask)
- else:
- encoder_extended_attention_mask = None
- # Prepare head mask if needed
- # 1.0 in head_mask indicate we keep the head
- # attention_probs has shape bsz x n_heads x N x N
- # input head_mask has shape [num_heads] or [num_hidden_layers x num_heads]
- # and head_mask is converted to shape [num_hidden_layers x batch x num_heads x seq_length x seq_length]
- head_mask = self.get_head_mask(head_mask,
- self.config.num_hidden_layers)
- embedding_output = self.embeddings(
- input_ids=input_ids,
- position_ids=position_ids,
- token_type_ids=token_type_ids,
- inputs_embeds=inputs_embeds,
- past_key_values_length=past_key_values_length,
- )
- encoder_outputs = self.encoder(
- embedding_output,
- attention_mask=extended_attention_mask,
- head_mask=head_mask,
- encoder_hidden_states=encoder_hidden_states,
- encoder_attention_mask=encoder_extended_attention_mask,
- past_key_values=past_key_values,
- use_cache=use_cache,
- output_attentions=output_attentions,
- output_hidden_states=output_hidden_states,
- return_dict=return_dict,
- )
- sequence_output = encoder_outputs[0]
- pooled_output = self.pooler(
- sequence_output) if self.pooler is not None else None
- if not return_dict:
- return (sequence_output, pooled_output) + encoder_outputs[1:]
- return AttentionBackboneModelOutput(
- last_hidden_state=sequence_output,
- pooler_output=pooled_output,
- past_key_values=encoder_outputs.past_key_values,
- hidden_states=encoder_outputs.hidden_states,
- attentions=encoder_outputs.attentions,
- cross_attentions=encoder_outputs.cross_attentions,
- )
- def extract_sequence_outputs(self, outputs):
- return outputs['last_hidden_state']
- def extract_pooled_outputs(self, outputs):
- return outputs['pooler_output']
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