diff --git "a/modeling_bert.py" "b/modeling_bert.py" new file mode 100644--- /dev/null +++ "b/modeling_bert.py" @@ -0,0 +1,2416 @@ +# coding=utf-8 +# 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 os +import warnings +from dataclasses import dataclass +from typing import List, Optional, Tuple, Union +import numpy as np + +import torch +import torch.utils.checkpoint +from torch import nn +from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss + +from transformers.activations import ACT2FN +from transformers.modeling_outputs import ( + BaseModelOutputWithPastAndCrossAttentions, + BaseModelOutputWithPoolingAndCrossAttentions, + CausalLMOutputWithCrossAttentions, + MaskedLMOutput, + MultipleChoiceModelOutput, + NextSentencePredictorOutput, + QuestionAnsweringModelOutput, + SequenceClassifierOutput, + TokenClassifierOutput, +) +from transformers.modeling_utils import PreTrainedModel +from transformers.pytorch_utils import ( + apply_chunking_to_forward, + find_pruneable_heads_and_indices, + prune_linear_layer, +) +from transformers.utils import ( + ModelOutput, + add_code_sample_docstrings, + add_start_docstrings, + add_start_docstrings_to_model_forward, + logging, + replace_return_docstrings, +) +from .configuration_bert import MyBertConfig + +try: + from tqdm.autonotebook import trange + + has_tqdm = True +except ImportError: + has_tqdm = False + +logger = logging.get_logger(__name__) + +_CHECKPOINT_FOR_DOC = "bert-base-uncased" +_CONFIG_FOR_DOC = "MyBertConfig" + +# TokenClassification docstring +_CHECKPOINT_FOR_TOKEN_CLASSIFICATION = ( + "dbmdz/bert-large-cased-finetuned-conll03-english" +) +_TOKEN_CLASS_EXPECTED_OUTPUT = "['O', 'I-ORG', 'I-ORG', 'I-ORG', 'O', 'O', 'O', 'O', 'O', 'I-LOC', 'O', 'I-LOC', 'I-LOC'] " +_TOKEN_CLASS_EXPECTED_LOSS = 0.01 + +# QuestionAnswering docstring +_CHECKPOINT_FOR_QA = "deepset/bert-base-cased-squad2" +_QA_EXPECTED_OUTPUT = "'a nice puppet'" +_QA_EXPECTED_LOSS = 7.41 +_QA_TARGET_START_INDEX = 14 +_QA_TARGET_END_INDEX = 15 + +# SequenceClassification docstring +_CHECKPOINT_FOR_SEQUENCE_CLASSIFICATION = "textattack/bert-base-uncased-yelp-polarity" +_SEQ_CLASS_EXPECTED_OUTPUT = "'LABEL_1'" +_SEQ_CLASS_EXPECTED_LOSS = 0.01 + + +BERT_PRETRAINED_MODEL_ARCHIVE_LIST = [ + "bert-base-uncased", + "bert-large-uncased", + "bert-base-cased", + "bert-large-cased", + "bert-base-multilingual-uncased", + "bert-base-multilingual-cased", + "bert-base-chinese", + "bert-base-german-cased", + "bert-large-uncased-whole-word-masking", + "bert-large-cased-whole-word-masking", + "bert-large-uncased-whole-word-masking-finetuned-squad", + "bert-large-cased-whole-word-masking-finetuned-squad", + "bert-base-cased-finetuned-mrpc", + "bert-base-german-dbmdz-cased", + "bert-base-german-dbmdz-uncased", + "cl-tohoku/bert-base-japanese", + "cl-tohoku/bert-base-japanese-whole-word-masking", + "cl-tohoku/bert-base-japanese-char", + "cl-tohoku/bert-base-japanese-char-whole-word-masking", + "TurkuNLP/bert-base-finnish-cased-v1", + "TurkuNLP/bert-base-finnish-uncased-v1", + "wietsedv/bert-base-dutch-cased", + # See all BERT models at https://huggingface.co/models?filter=bert +] + + +def load_tf_weights_in_bert(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): + name = name.split("/") + # adam_v and adam_m are variables used in AdamWeightDecayOptimizer to calculated m and v + # which are not required for using pretrained model + if any( + n + in [ + "adam_v", + "adam_m", + "AdamWeightDecayOptimizer", + "AdamWeightDecayOptimizer_1", + "global_step", + ] + for n 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 ValueError as e: + e.args += (pointer.shape, array.shape) + raise + logger.info(f"Initialize PyTorch weight {name}") + pointer.data = torch.from_numpy(array) + return model + + +class MyBertEmbeddings(nn.Module): + """Construct the embeddings from word, position and token_type embeddings.""" + + def __init__(self, config: MyBertConfig): + super().__init__() + self.word_embeddings = nn.Embedding( + config.vocab_size, config.hidden_size, padding_idx=config.pad_token_id + ) + if config.position_embedding_type != "alibi": + 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)), + persistent=False, + ) + self.register_buffer( + "token_type_ids", + torch.zeros(self.position_ids.size(), dtype=torch.long), + persistent=False, + ) + + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + token_type_ids: Optional[torch.LongTensor] = None, + position_ids: Optional[torch.LongTensor] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + past_key_values_length: int = 0, + ) -> torch.Tensor: + 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 MyBertSelfAttention(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: torch.Tensor) -> torch.Tensor: + 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: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + encoder_hidden_states: Optional[torch.FloatTensor] = None, + encoder_attention_mask: Optional[torch.FloatTensor] = None, + past_key_value: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + output_attentions: Optional[bool] = False, + bias: Optional[torch.FloatTensor] = None, + ) -> Tuple[torch.Tensor]: + 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) + + use_cache = past_key_value is not None + 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" + ): + query_length, key_length = query_layer.shape[2], key_layer.shape[2] + if use_cache: + position_ids_l = torch.tensor( + key_length - 1, dtype=torch.long, device=hidden_states.device + ).view(-1, 1) + else: + position_ids_l = torch.arange( + query_length, dtype=torch.long, device=hidden_states.device + ).view(-1, 1) + position_ids_r = torch.arange( + key_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 + bias, 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 MyBertSelfOutput(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: torch.Tensor, input_tensor: torch.Tensor + ) -> torch.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 MyBertAttention(nn.Module): + def __init__(self, config, position_embedding_type=None): + super().__init__() + self.self = MyBertSelfAttention( + config, position_embedding_type=position_embedding_type + ) + self.output = MyBertSelfOutput(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: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + encoder_hidden_states: Optional[torch.FloatTensor] = None, + encoder_attention_mask: Optional[torch.FloatTensor] = None, + past_key_value: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + output_attentions: Optional[bool] = False, + bias: Optional[torch.FloatTensor] = None, + ) -> Tuple[torch.Tensor]: + self_outputs = self.self( + hidden_states, + attention_mask, + head_mask, + encoder_hidden_states, + encoder_attention_mask, + past_key_value, + output_attentions, + bias, + ) + attention_output = self.output(self_outputs[0], hidden_states) + outputs = (attention_output,) + self_outputs[ + 1: + ] # add attentions if we output them + return outputs + + +class MyBertIntermediate(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: torch.Tensor) -> torch.Tensor: + hidden_states = self.dense(hidden_states) + hidden_states = self.intermediate_act_fn(hidden_states) + return hidden_states + + +class MyBertOutput(nn.Module): + def __init__(self, config: MyBertConfig): + 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: torch.Tensor, input_tensor: torch.Tensor + ) -> torch.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 MyBertGLUMLP(nn.Module): + def __init__(self, config: MyBertConfig): + super().__init__() + self.config = config + self.gated_layers = nn.Linear( + config.hidden_size, config.intermediate_size * 2, bias=False + ) + if config.feed_forward_type == 'reglu': + self.act = nn.ReLU() + elif config.feed_forward_type == 'geglu': + self.act = nn.GELU() + else: + raise ValueError( + f"feed_forward_type {config.feed_forward_type} not supported" + ) + self.wo = nn.Linear(config.intermediate_size, config.hidden_size) + self.dropout = nn.Dropout(config.hidden_dropout_prob) + self.layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + residual_connection = hidden_states + # compute the activation + hidden_states = self.gated_layers(hidden_states) + gated = hidden_states[:, :, : self.config.intermediate_size] + non_gated = hidden_states[:, :, self.config.intermediate_size :] + hidden_states = self.act(gated) * non_gated + hidden_states = self.dropout(hidden_states) + # multiply by the second matrix + hidden_states = self.wo(hidden_states) + # add the residual connection and post-LN + hidden_states = self.layernorm(hidden_states + residual_connection) + return hidden_states + + +class MyBertLayer(nn.Module): + def __init__(self, config: MyBertConfig): + super().__init__() + self.chunk_size_feed_forward = config.chunk_size_feed_forward + self.seq_len_dim = 1 + self.attention = MyBertAttention(config) + self.is_decoder = config.is_decoder + self.add_cross_attention = config.add_cross_attention + self.feed_forward_type = config.feed_forward_type + 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 = MyBertAttention( + config, position_embedding_type="absolute" + ) + if self.feed_forward_type.endswith('glu'): + self.mlp = MyBertGLUMLP(config) + else: + self.intermediate = MyBertIntermediate(config) + self.output = MyBertOutput(config) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + encoder_hidden_states: Optional[torch.FloatTensor] = None, + encoder_attention_mask: Optional[torch.FloatTensor] = None, + bias: Optional[torch.FloatTensor] = None, + past_key_value: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + output_attentions: Optional[bool] = False, + ) -> Tuple[torch.Tensor]: + # 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, + bias=bias, + ) + 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 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 + + if self.feed_forward_type.endswith('glu'): + layer_output = self.mlp(attention_output) + else: + 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 MyBertEncoder(nn.Module): + def __init__(self, config: MyBertConfig): + super().__init__() + self.config = config + self.layer = nn.ModuleList( + [MyBertLayer(config) for _ in range(config.num_hidden_layers)] + ) + self.gradient_checkpointing = False + self.num_attention_heads = config.num_attention_heads + self.register_buffer( + "alibi", + self.rebuild_alibi_tensor(size=config.max_position_embeddings), + persistent=False, + ) + + def rebuild_alibi_tensor( + self, size: int, device: Optional[Union[torch.device, str]] = None + ): + # Alibi + # Following https://github.com/ofirpress/attention_with_linear_biases/issues/5 (Implementation 1) + # In the causal case, you can exploit the fact that softmax is invariant to a uniform translation + # of the logits, which makes the math work out *after* applying causal masking. If no causal masking + # will be applied, it is necessary to construct the diagonal mask. + n_heads = self.num_attention_heads + + # Mosaics one + # def _get_alibi_head_slopes(n_heads: int) -> List[float]: + # def get_slopes_power_of_2(n_heads: int) -> List[float]: + # start = 2 ** (-(2 ** -(math.log2(n_heads) - 3))) + # ratio = start + # return [start * ratio**i for i in range(n_heads)] + + # # In the paper, they only train models that have 2^a heads for some a. This function + # # has some good properties that only occur when the input is a power of 2. To + # # maintain that even when the number of heads is not a power of 2, we use a + # # workaround. + # if math.log2(n_heads).is_integer(): + # return get_slopes_power_of_2(n_heads) + + # closest_power_of_2 = 2 ** math.floor(math.log2(n_heads)) + # slopes_a = get_slopes_power_of_2(closest_power_of_2) + # slopes_b = _get_alibi_head_slopes(2 * closest_power_of_2) + # slopes_b = slopes_b[0::2][: n_heads - closest_power_of_2] + # return slopes_a + slopes_b + + def _get_alibi_head_slopes(n_heads: int) -> List[float]: + def get_slopes_power_of_2(n): + start = 2 ** (-(2 ** -(math.log2(n) - 3))) + ratio = start + return [start * ratio**i for i in range(n)] + + if math.log2(n_heads).is_integer(): + return get_slopes_power_of_2( + n_heads + ) # In the paper, we only train models that have 2^a heads for some a. This function has + else: # some good properties that only occur when the input is a power of 2. To maintain that even + closest_power_of_2 = 2 ** math.floor( + math.log2(n_heads) + ) # when the number of heads is not a power of 2, we use this workaround. + return ( + get_slopes_power_of_2(closest_power_of_2) + + _get_alibi_head_slopes(2 * closest_power_of_2)[0::2][ + : n_heads - closest_power_of_2 + ] + ) + + context_position = torch.arange(size, device=device)[:, None] + memory_position = torch.arange(size, device=device)[None, :] + relative_position = torch.abs(memory_position - context_position) + # [n_heads, max_token_length, max_token_length] + relative_position = relative_position.unsqueeze(0).expand(n_heads, -1, -1) + slopes = torch.Tensor(_get_alibi_head_slopes(n_heads)).to(device) * -1 + alibi = slopes.unsqueeze(1).unsqueeze(1) * relative_position + # [1, n_heads, max_token_length, max_token_length] + alibi = alibi.unsqueeze(0) + assert alibi.shape == torch.Size([1, n_heads, size, size]) + + self._current_alibi_size = size + return alibi + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + encoder_hidden_states: Optional[torch.FloatTensor] = None, + encoder_attention_mask: Optional[torch.FloatTensor] = None, + past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = False, + output_hidden_states: Optional[bool] = False, + return_dict: Optional[bool] = True, + ) -> Union[Tuple[torch.Tensor], BaseModelOutputWithPastAndCrossAttentions]: + 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 + ) + + # Add alibi matrix to extended_attention_mask + _, seqlen, _ = hidden_states.size() + if self._current_alibi_size < seqlen: + # Rebuild the alibi tensor when needed + warnings.warn( + f'Increasing alibi size from {self._current_alibi_size} to {seqlen}.' + ) + self.register_buffer( + "alibi", + self.rebuild_alibi_tensor(size=seqlen, device=hidden_states.device).to( + hidden_states.dtype + ), + persistent=False, + ) + elif self.alibi.device != hidden_states.device: + # Device catch-up + self.alibi = self.alibi.to(hidden_states.device) + + alibi_bias = self.alibi[:, :, :seqlen, :seqlen] + if self.gradient_checkpointing and self.training: + if use_cache: + logger.warning_once( + "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`..." + ) + use_cache = False + + 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: + + 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, + alibi_bias, + ) + else: + layer_outputs = layer_module( + hidden_states, + attention_mask, + layer_head_mask, + encoder_hidden_states, + encoder_attention_mask, + alibi_bias, + 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 BaseModelOutputWithPastAndCrossAttentions( + 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 MyBertPooler(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: torch.Tensor) -> torch.Tensor: + # 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 MyBertPredictionHeadTransform(nn.Module): + def __init__(self, config): + super().__init__() + self.dense = nn.Linear(config.hidden_size, config.hidden_size) + if isinstance(config.hidden_act, str): + self.transform_act_fn = ACT2FN[config.hidden_act] + else: + self.transform_act_fn = config.hidden_act + self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + hidden_states = self.dense(hidden_states) + hidden_states = self.transform_act_fn(hidden_states) + hidden_states = self.LayerNorm(hidden_states) + return hidden_states + + +class MyBertLMPredictionHead(nn.Module): + def __init__(self, config): + super().__init__() + self.transform = MyBertPredictionHeadTransform(config) + + # The output weights are the same as the input embeddings, but there is + # an output-only bias for each token. + self.decoder = nn.Linear(config.hidden_size, config.vocab_size, bias=False) + + self.bias = nn.Parameter(torch.zeros(config.vocab_size)) + + # Need a link between the two variables so that the bias is correctly resized with `resize_token_embeddings` + self.decoder.bias = self.bias + + def forward(self, hidden_states): + hidden_states = self.transform(hidden_states) + hidden_states = self.decoder(hidden_states) + return hidden_states + + +class MyBertOnlyMLMHead(nn.Module): + def __init__(self, config): + super().__init__() + self.predictions = MyBertLMPredictionHead(config) + + def forward(self, sequence_output: torch.Tensor) -> torch.Tensor: + prediction_scores = self.predictions(sequence_output) + return prediction_scores + + +class MyBertOnlyNSPHead(nn.Module): + def __init__(self, config): + super().__init__() + self.seq_relationship = nn.Linear(config.hidden_size, 2) + + def forward(self, pooled_output): + seq_relationship_score = self.seq_relationship(pooled_output) + return seq_relationship_score + + +class MyBertPreTrainingHeads(nn.Module): + def __init__(self, config): + super().__init__() + self.predictions = MyBertLMPredictionHead(config) + self.seq_relationship = nn.Linear(config.hidden_size, 2) + + def forward(self, sequence_output, pooled_output): + prediction_scores = self.predictions(sequence_output) + seq_relationship_score = self.seq_relationship(pooled_output) + return prediction_scores, seq_relationship_score + + +class MyBertPreTrainedModel(PreTrainedModel): + """ + An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained + models. + """ + + config_class = MyBertConfig + load_tf_weights = load_tf_weights_in_bert + base_model_prefix = "bert" + supports_gradient_checkpointing = True + + 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, MyBertEncoder): + module.gradient_checkpointing = value + + +@dataclass +class MyBertForPreTrainingOutput(ModelOutput): + """ + Output type of [`BertForPreTraining`]. + + Args: + loss (*optional*, returned when `labels` is provided, `torch.FloatTensor` of shape `(1,)`): + Total loss as the sum of the masked language modeling loss and the next sequence prediction + (classification) loss. + prediction_logits (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.vocab_size)`): + Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax). + seq_relationship_logits (`torch.FloatTensor` of shape `(batch_size, 2)`): + Prediction scores of the next sequence prediction (classification) head (scores of True/False continuation + before SoftMax). + hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the model at the output of each layer plus the initial embedding outputs. + attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(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 + seq_relationship_logits: torch.FloatTensor = None + hidden_states: Optional[Tuple[torch.FloatTensor]] = None + attentions: Optional[Tuple[torch.FloatTensor]] = None + + +BERT_START_DOCSTRING = r""" + + 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. +""" + +BERT_INPUTS_DOCSTRING = r""" + Args: + input_ids (`torch.LongTensor` of shape `({0})`): + Indices of input sequence tokens in the vocabulary. + + Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for details. + + [What are input IDs?](../glossary#input-ids) + attention_mask (`torch.FloatTensor` of shape `({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#attention-mask) + token_type_ids (`torch.LongTensor` of shape `({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#token-type-ids) + position_ids (`torch.LongTensor` of shape `({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#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 `({0}, 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 [`~utils.ModelOutput`] instead of a plain tuple. +""" + + +@add_start_docstrings( + "The bare Bert Model transformer outputting raw hidden-states without any specific head on top.", + BERT_START_DOCSTRING, +) +class MyBertModel(MyBertPreTrainedModel): + """ + + 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: MyBertConfig, add_pooling_layer=True): + super().__init__(config) + self.config = config + + self.emb_pooler = config.emb_pooler + self._name_or_path = config._name_or_path + if self.emb_pooler: + from transformers import AutoTokenizer + + self.tokenizer = AutoTokenizer.from_pretrained(config._name_or_path) + + self.embeddings = MyBertEmbeddings(config) + self.encoder = MyBertEncoder(config) + + self.pooler = MyBertPooler(config) if add_pooling_layer else None + + # Initialize weights and apply final processing + self.post_init() + + @torch.inference_mode() + def encode( + self: 'MyBertModel', + sentences: Union[str, List[str]], + batch_size: int = 32, + show_progress_bar: Optional[bool] = None, + output_value: str = 'sentence_embedding', + convert_to_numpy: bool = True, + convert_to_tensor: bool = False, + device: Optional[torch.device] = None, + normalize_embeddings: bool = False, + **tokenizer_kwargs, + ) -> Union[List[torch.Tensor], np.ndarray, torch.Tensor]: + """ + Computes sentence embeddings + + Args: + sentences(`str` or `List[str]`): + Sentence or sentences to be encoded + batch_size(`int`, *optional*, defaults to 32): + Batch size for the computation + show_progress_bar(`bool`, *optional*, defaults to None): + Show a progress bar when encoding sentences. + If set to None, progress bar is only shown when `logger.level == logging.INFO` or `logger.level == logging.DEBUG`. + output_value(`str`, *optional*, defaults to 'sentence_embedding'): + Default sentence_embedding, to get sentence embeddings. + Can be set to token_embeddings to get wordpiece token embeddings. + Set to None, to get all output values + convert_to_numpy(`bool`, *optional*, defaults to True): + If true, the output is a list of numpy vectors. + Else, it is a list of pytorch tensors. + convert_to_tensor(`bool`, *optional*, defaults to False): + If true, you get one large tensor as return. + Overwrites any setting from convert_to_numpy + device(`torch.device`, *optional*, defaults to None): + Which torch.device to use for the computation + normalize_embeddings(`bool`, *optional*, defaults to False): + If set to true, returned vectors will have length 1. In that case, the faster dot-product (util.dot_score) instead of cosine similarity can be used. + tokenizer_kwargs(`Dict[str, Any]`, *optional*, defaults to {}): + Keyword arguments for the tokenizer + + Returns: + By default, a list of tensors is returned. + If convert_to_tensor, a stacked tensor is returned. + If convert_to_numpy, a numpy matrix is returned. + """ + if not self.emb_pooler: + warnings.warn("No emb_pooler specified, defaulting to mean pooling.") + self.emb_pooler = 'mean' + from transformers import AutoTokenizer + + self.tokenizer = AutoTokenizer.from_pretrained(self._name_or_path) + is_training = self.training + self.eval() + + if show_progress_bar is None: + show_progress_bar = ( + logger.getEffectiveLevel() == logging.INFO + or logger.getEffectiveLevel() == logging.DEBUG + ) + + if convert_to_tensor: + convert_to_numpy = False + + if output_value != 'sentence_embedding': + convert_to_tensor = False + convert_to_numpy = False + + input_was_string = False + if isinstance(sentences, str) or not hasattr(sentences, '__len__'): + sentences = [sentences] + input_was_string = True + + if device is not None: + self.to(device) + + # TODO: Maybe use better length heuristic? + inverse_permutation = np.argsort(np.argsort([-len(i) for i in sentences])) + sentences = sorted(sentences, key=len, reverse=True) + + padding = tokenizer_kwargs.pop('padding', True) + + all_embeddings = [] + + if has_tqdm: + range_iter = trange( + 0, + len(sentences), + batch_size, + desc="Encoding", + disable=not show_progress_bar, + ) + else: + range_iter = range(0, len(sentences), batch_size) + + for i in range_iter: + encoded_input = self.tokenizer( + sentences[i : i + batch_size], + return_tensors='pt', + padding=padding, + **tokenizer_kwargs, + ).to(self.device) + token_embs = self.forward(**encoded_input)[0] + + # Accumulate in fp32 to avoid overflow + token_embs = token_embs.float() + + if output_value == 'token_embeddings': + raise NotImplementedError + elif output_value is None: + raise NotImplementedError + else: + embeddings = self.mean_pooling( + token_embs, encoded_input['attention_mask'] + ) + + if normalize_embeddings: + embeddings = torch.nn.functional.normalize(embeddings, p=2, dim=1) + + if convert_to_numpy: + embeddings = embeddings.cpu() + all_embeddings.extend(embeddings) + + all_embeddings = [all_embeddings[idx] for idx in inverse_permutation] + + if convert_to_tensor: + all_embeddings = torch.stack(all_embeddings) + elif convert_to_numpy: + all_embeddings = np.asarray([emb.numpy() for emb in all_embeddings]) + + if input_was_string: + all_embeddings = all_embeddings[0] + + self.train(is_training) + return all_embeddings + + def mean_pooling( + self, token_embeddings: torch.Tensor, attention_mask: torch.Tensor + ): + input_mask_expanded = ( + attention_mask.unsqueeze(-1).expand(token_embeddings.size()).float() + ) + return torch.sum(token_embeddings * input_mask_expanded, 1) / torch.clamp( + input_mask_expanded.sum(1), min=1e-9 + ) + + 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) + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_DOC, + output_type=BaseModelOutputWithPoolingAndCrossAttentions, + config_class=_CONFIG_FOR_DOC, + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + encoder_hidden_states: Optional[torch.Tensor] = None, + encoder_attention_mask: Optional[torch.Tensor] = None, + past_key_values: Optional[List[torch.FloatTensor]] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], BaseModelOutputWithPoolingAndCrossAttentions]: + r""" + 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`). + """ + 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: + # self.warn_if_padding_and_no_attention_mask(input_ids, attention_mask) + 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 + ) + + # 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 BaseModelOutputWithPoolingAndCrossAttentions( + 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, + ) + + +@add_start_docstrings( + """ + Bert Model with two heads on top as done during the pretraining: a `masked language modeling` head and a `next + sentence prediction (classification)` head. + """, + BERT_START_DOCSTRING, +) +class MyBertForPreTraining(MyBertPreTrainedModel): + _tied_weights_keys = ["predictions.decoder.bias", "cls.predictions.decoder.weight"] + + def __init__(self, config): + super().__init__(config) + + self.bert = MyBertModel(config) + self.cls = MyBertPreTrainingHeads(config) + + # Initialize weights and apply final processing + self.post_init() + + def get_output_embeddings(self): + return self.cls.predictions.decoder + + def set_output_embeddings(self, new_embeddings): + self.cls.predictions.decoder = new_embeddings + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @replace_return_docstrings( + output_type=MyBertForPreTrainingOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + next_sentence_label: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], MyBertForPreTrainingOutput]: + 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]` + next_sentence_label (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the next sequence prediction (classification) loss. Input should be a sequence + pair (see `input_ids` docstring) Indices should be in `[0, 1]`: + + - 0 indicates sequence B is a continuation of sequence A, + - 1 indicates sequence B is a random sequence. + kwargs (`Dict[str, any]`, optional, defaults to *{}*): + Used to hide legacy arguments that have been deprecated. + + Returns: + + Example: + + ```python + >>> from transformers import AutoTokenizer, MyBertForPreTraining + >>> import torch + + >>> tokenizer = AutoTokenizer.from_pretrained("bert-base-uncased") + >>> model = MyBertForPreTraining.from_pretrained("bert-base-uncased") + + >>> inputs = tokenizer("Hello, my dog is cute", return_tensors="pt") + >>> outputs = model(**inputs) + + >>> prediction_logits = outputs.prediction_logits + >>> seq_relationship_logits = outputs.seq_relationship_logits + ``` + """ + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + outputs = self.bert( + 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, seq_relationship_score = self.cls( + sequence_output, pooled_output + ) + + total_loss = None + if labels is not None and next_sentence_label is not None: + loss_fct = CrossEntropyLoss() + masked_lm_loss = loss_fct( + prediction_scores.view(-1, self.config.vocab_size), labels.view(-1) + ) + next_sentence_loss = loss_fct( + seq_relationship_score.view(-1, 2), next_sentence_label.view(-1) + ) + total_loss = masked_lm_loss + next_sentence_loss + + if not return_dict: + output = (prediction_scores, seq_relationship_score) + outputs[2:] + return ((total_loss,) + output) if total_loss is not None else output + + return MyBertForPreTrainingOutput( + loss=total_loss, + prediction_logits=prediction_scores, + seq_relationship_logits=seq_relationship_score, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + ) + + +@add_start_docstrings( + """MyBert Model with a `language modeling` head on top for CLM fine-tuning.""", + BERT_START_DOCSTRING, +) +class MyBertLMHeadModel(MyBertPreTrainedModel): + _tied_weights_keys = ["predictions.decoder.bias", "cls.predictions.decoder.weight"] + + def __init__(self, config): + super().__init__(config) + + if not config.is_decoder: + logger.warning( + "If you want to use `MyBertLMHeadModel` as a standalone, add `is_decoder=True.`" + ) + + self.bert = MyBertModel(config, add_pooling_layer=False) + self.cls = MyBertOnlyMLMHead(config) + + # Initialize weights and apply final processing + self.post_init() + + def get_output_embeddings(self): + return self.cls.predictions.decoder + + def set_output_embeddings(self, new_embeddings): + self.cls.predictions.decoder = new_embeddings + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_DOC, + output_type=CausalLMOutputWithCrossAttentions, + config_class=_CONFIG_FOR_DOC, + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + encoder_hidden_states: Optional[torch.Tensor] = None, + encoder_attention_mask: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + past_key_values: Optional[List[torch.Tensor]] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], CausalLMOutputWithCrossAttentions]: + r""" + 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**. + labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*): + Labels for computing the left-to-right language modeling loss (next word prediction). 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 n `[0, ..., config.vocab_size]` + 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`). + """ + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + if labels is not None: + use_cache = False + + outputs = self.bert( + input_ids, + attention_mask=attention_mask, + token_type_ids=token_type_ids, + position_ids=position_ids, + head_mask=head_mask, + inputs_embeds=inputs_embeds, + encoder_hidden_states=encoder_hidden_states, + encoder_attention_mask=encoder_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 = outputs[0] + prediction_scores = self.cls(sequence_output) + + lm_loss = None + if labels is not None: + # we are doing next-token prediction; shift prediction scores and input ids by one + shifted_prediction_scores = prediction_scores[:, :-1, :].contiguous() + labels = labels[:, 1:].contiguous() + loss_fct = CrossEntropyLoss() + lm_loss = loss_fct( + shifted_prediction_scores.view(-1, self.config.vocab_size), + labels.view(-1), + ) + + if not return_dict: + output = (prediction_scores,) + outputs[2:] + return ((lm_loss,) + output) if lm_loss is not None else output + + return CausalLMOutputWithCrossAttentions( + loss=lm_loss, + logits=prediction_scores, + past_key_values=outputs.past_key_values, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + def prepare_inputs_for_generation( + self, + input_ids, + past_key_values=None, + attention_mask=None, + use_cache=True, + **model_kwargs, + ): + input_shape = input_ids.shape + # if model is used as a decoder in encoder-decoder model, the decoder attention mask is created on the fly + if attention_mask is None: + attention_mask = input_ids.new_ones(input_shape) + + # cut decoder_input_ids if past_key_values is used + if past_key_values is not None: + input_ids = input_ids[:, -1:] + + return { + "input_ids": input_ids, + "attention_mask": attention_mask, + "past_key_values": past_key_values, + "use_cache": use_cache, + } + + def _reorder_cache(self, past_key_values, beam_idx): + reordered_past = () + for layer_past in past_key_values: + reordered_past += ( + tuple( + past_state.index_select(0, beam_idx) for past_state in layer_past + ), + ) + return reordered_past + + +@add_start_docstrings( + """MyBert Model with a `language modeling` head on top.""", BERT_START_DOCSTRING +) +class MyBertForMaskedLM(MyBertPreTrainedModel): + _tied_weights_keys = ["predictions.decoder.bias", "cls.predictions.decoder.weight"] + + def __init__(self, config): + super().__init__(config) + + if config.is_decoder: + logger.warning( + "If you want to use `MyBertForMaskedLM` make sure `config.is_decoder=False` for " + "bi-directional self-attention." + ) + + self.bert = MyBertModel(config, add_pooling_layer=False) + self.cls = MyBertOnlyMLMHead(config) + + # Initialize weights and apply final processing + self.post_init() + + def get_output_embeddings(self): + return self.cls.predictions.decoder + + def set_output_embeddings(self, new_embeddings): + self.cls.predictions.decoder = new_embeddings + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_DOC, + output_type=MaskedLMOutput, + config_class=_CONFIG_FOR_DOC, + expected_output="'paris'", + expected_loss=0.88, + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + encoder_hidden_states: Optional[torch.Tensor] = None, + encoder_attention_mask: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], MaskedLMOutput]: + 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]` + """ + + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + outputs = self.bert( + input_ids, + attention_mask=attention_mask, + token_type_ids=token_type_ids, + position_ids=position_ids, + head_mask=head_mask, + inputs_embeds=inputs_embeds, + encoder_hidden_states=encoder_hidden_states, + encoder_attention_mask=encoder_attention_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + sequence_output = outputs[0] + prediction_scores = self.cls(sequence_output) + + masked_lm_loss = None + if labels is not None: + loss_fct = CrossEntropyLoss() # -100 index = padding token + 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, + ) + + def prepare_inputs_for_generation( + self, input_ids, attention_mask=None, **model_kwargs + ): + input_shape = input_ids.shape + effective_batch_size = input_shape[0] + + # add a dummy token + if self.config.pad_token_id is None: + raise ValueError("The PAD token should be defined for generation") + + attention_mask = torch.cat( + [attention_mask, attention_mask.new_zeros((attention_mask.shape[0], 1))], + dim=-1, + ) + dummy_token = torch.full( + (effective_batch_size, 1), + self.config.pad_token_id, + dtype=torch.long, + device=input_ids.device, + ) + input_ids = torch.cat([input_ids, dummy_token], dim=1) + + return {"input_ids": input_ids, "attention_mask": attention_mask} + + +@add_start_docstrings( + """MyBert Model with a `next sentence prediction (classification)` head on top.""", + BERT_START_DOCSTRING, +) +class MyBertForNextSentencePrediction(MyBertPreTrainedModel): + def __init__(self, config): + super().__init__(config) + + self.bert = MyBertModel(config) + self.cls = MyBertOnlyNSPHead(config) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @replace_return_docstrings( + output_type=NextSentencePredictorOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + **kwargs, + ) -> Union[Tuple[torch.Tensor], NextSentencePredictorOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the next sequence prediction (classification) loss. Input should be a sequence pair + (see `input_ids` docstring). Indices should be in `[0, 1]`: + + - 0 indicates sequence B is a continuation of sequence A, + - 1 indicates sequence B is a random sequence. + + Returns: + + Example: + + ```python + >>> from transformers import AutoTokenizer, MyBertForNextSentencePrediction + >>> import torch + + >>> tokenizer = AutoTokenizer.from_pretrained("bert-base-uncased") + >>> model = MyBertForNextSentencePrediction.from_pretrained("bert-base-uncased") + + >>> prompt = "In Italy, pizza served in formal settings, such as at a restaurant, is presented unsliced." + >>> next_sentence = "The sky is blue due to the shorter wavelength of blue light." + >>> encoding = tokenizer(prompt, next_sentence, return_tensors="pt") + + >>> outputs = model(**encoding, labels=torch.LongTensor([1])) + >>> logits = outputs.logits + >>> assert logits[0, 0] < logits[0, 1] # next sentence was random + ``` + """ + + if "next_sentence_label" in kwargs: + warnings.warn( + "The `next_sentence_label` argument is deprecated and will be removed in a future version, use" + " `labels` instead.", + FutureWarning, + ) + labels = kwargs.pop("next_sentence_label") + + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + outputs = self.bert( + 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] + + seq_relationship_scores = self.cls(pooled_output) + + next_sentence_loss = None + if labels is not None: + loss_fct = CrossEntropyLoss() + next_sentence_loss = loss_fct( + seq_relationship_scores.view(-1, 2), labels.view(-1) + ) + + if not return_dict: + output = (seq_relationship_scores,) + outputs[2:] + return ( + ((next_sentence_loss,) + output) + if next_sentence_loss is not None + else output + ) + + return NextSentencePredictorOutput( + loss=next_sentence_loss, + logits=seq_relationship_scores, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + ) + + +@add_start_docstrings( + """ + MyBert Model transformer with a sequence classification/regression head on top (a linear layer on top of the pooled + output) e.g. for GLUE tasks. + """, + BERT_START_DOCSTRING, +) +class MyBertForSequenceClassification(MyBertPreTrainedModel): + def __init__(self, config): + super().__init__(config) + self.num_labels = config.num_labels + self.config = config + + self.bert = MyBertModel(config) + classifier_dropout = ( + config.classifier_dropout + if config.classifier_dropout is not None + else config.hidden_dropout_prob + ) + self.dropout = nn.Dropout(classifier_dropout) + self.classifier = nn.Linear(config.hidden_size, config.num_labels) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_SEQUENCE_CLASSIFICATION, + output_type=SequenceClassifierOutput, + config_class=_CONFIG_FOR_DOC, + expected_output=_SEQ_CLASS_EXPECTED_OUTPUT, + expected_loss=_SEQ_CLASS_EXPECTED_LOSS, + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], SequenceClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(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.bert( + 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( + """ + MyBert 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. + """, + BERT_START_DOCSTRING, +) +class MyBertForMultipleChoice(MyBertPreTrainedModel): + def __init__(self, config): + super().__init__(config) + + self.bert = MyBertModel(config) + classifier_dropout = ( + config.classifier_dropout + if config.classifier_dropout is not None + else config.hidden_dropout_prob + ) + self.dropout = nn.Dropout(classifier_dropout) + self.classifier = nn.Linear(config.hidden_size, 1) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, num_choices, sequence_length") + ) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_DOC, + output_type=MultipleChoiceModelOutput, + config_class=_CONFIG_FOR_DOC, + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], MultipleChoiceModelOutput]: + r""" + labels (`torch.LongTensor` of shape `(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.bert( + 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, + ) + + +@add_start_docstrings( + """ + MyBert 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. + """, + BERT_START_DOCSTRING, +) +class MyBertForTokenClassification(MyBertPreTrainedModel): + def __init__(self, config): + super().__init__(config) + self.num_labels = config.num_labels + + self.bert = MyBertModel(config, add_pooling_layer=False) + classifier_dropout = ( + config.classifier_dropout + if config.classifier_dropout is not None + else config.hidden_dropout_prob + ) + self.dropout = nn.Dropout(classifier_dropout) + self.classifier = nn.Linear(config.hidden_size, config.num_labels) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_TOKEN_CLASSIFICATION, + output_type=TokenClassifierOutput, + config_class=_CONFIG_FOR_DOC, + expected_output=_TOKEN_CLASS_EXPECTED_OUTPUT, + expected_loss=_TOKEN_CLASS_EXPECTED_LOSS, + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], TokenClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(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.bert( + 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() + 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( + """ + MyBert 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`). + """, + BERT_START_DOCSTRING, +) +class MyBertForQuestionAnswering(MyBertPreTrainedModel): + def __init__(self, config): + super().__init__(config) + self.num_labels = config.num_labels + + self.bert = MyBertModel(config, add_pooling_layer=False) + self.qa_outputs = nn.Linear(config.hidden_size, config.num_labels) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward( + BERT_INPUTS_DOCSTRING.format("batch_size, sequence_length") + ) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_QA, + output_type=QuestionAnsweringModelOutput, + config_class=_CONFIG_FOR_DOC, + qa_target_start_index=_QA_TARGET_START_INDEX, + qa_target_end_index=_QA_TARGET_END_INDEX, + expected_output=_QA_EXPECTED_OUTPUT, + expected_loss=_QA_EXPECTED_LOSS, + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + token_type_ids: Optional[torch.Tensor] = None, + position_ids: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + start_positions: Optional[torch.Tensor] = None, + end_positions: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], QuestionAnsweringModelOutput]: + r""" + start_positions (`torch.LongTensor` of shape `(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 (`sequence_length`). Position outside of the sequence + are not taken into account for computing the loss. + end_positions (`torch.LongTensor` of shape `(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 (`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.bert( + 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, + )