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"""PyTorch BERT model.""" |
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from __future__ import absolute_import |
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from __future__ import division |
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from __future__ import print_function |
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import os |
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import copy |
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import json |
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import math |
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import logging |
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import tarfile |
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import tempfile |
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import shutil |
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import torch |
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from torch import nn |
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import torch.nn.functional as F |
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from .file_utils import cached_path |
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from .until_config import PretrainedConfig |
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from .until_module import PreTrainedModel, LayerNorm, ACT2FN |
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logger = logging.getLogger(__name__) |
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PRETRAINED_MODEL_ARCHIVE_MAP = {} |
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CONFIG_NAME = 'visual_config.json' |
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WEIGHTS_NAME = 'visual_pytorch_model.bin' |
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class VisualConfig(PretrainedConfig): |
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"""Configuration class to store the configuration of a `VisualModel`. |
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""" |
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pretrained_model_archive_map = PRETRAINED_MODEL_ARCHIVE_MAP |
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config_name = CONFIG_NAME |
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weights_name = WEIGHTS_NAME |
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def __init__(self, |
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vocab_size_or_config_json_file=4096, |
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hidden_size=768, |
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num_hidden_layers=3, |
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num_attention_heads=12, |
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intermediate_size=3072, |
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hidden_act="gelu", |
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hidden_dropout_prob=0.1, |
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attention_probs_dropout_prob=0.1, |
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max_position_embeddings=512, |
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initializer_range=0.02): |
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"""Constructs VisualConfig. |
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Args: |
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vocab_size_or_config_json_file: Size of the encoder layers and the pooler layer. |
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hidden_size: Size of the encoder layers and the pooler layer. |
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num_hidden_layers: Number of hidden layers in the Transformer encoder. |
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num_attention_heads: Number of attention heads for each attention layer in |
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the Transformer encoder. |
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intermediate_size: The size of the "intermediate" (i.e., feed-forward) |
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layer in the Transformer encoder. |
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hidden_act: The non-linear activation function (function or string) in the |
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encoder and pooler. If string, "gelu", "relu" and "swish" are supported. |
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hidden_dropout_prob: The dropout probabilitiy for all fully connected |
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layers in the embeddings, encoder, and pooler. |
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attention_probs_dropout_prob: The dropout ratio for the attention |
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probabilities. |
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max_position_embeddings: The maximum sequence length that this model might |
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ever be used with. Typically set this to something large just in case |
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(e.g., 512 or 1024 or 2048). |
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initializer_range: The sttdev of the truncated_normal_initializer for |
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initializing all weight matrices. |
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""" |
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if isinstance(vocab_size_or_config_json_file, str): |
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with open(vocab_size_or_config_json_file, "r", encoding='utf-8') as reader: |
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json_config = json.loads(reader.read()) |
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for key, value in json_config.items(): |
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self.__dict__[key] = value |
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elif isinstance(vocab_size_or_config_json_file, int): |
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self.vocab_size = vocab_size_or_config_json_file |
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self.hidden_size = hidden_size |
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self.num_hidden_layers = num_hidden_layers |
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self.num_attention_heads = num_attention_heads |
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self.hidden_act = hidden_act |
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self.intermediate_size = intermediate_size |
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self.hidden_dropout_prob = hidden_dropout_prob |
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self.attention_probs_dropout_prob = attention_probs_dropout_prob |
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self.max_position_embeddings = max_position_embeddings |
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self.initializer_range = initializer_range |
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else: |
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raise ValueError("First argument must be either a vocabulary size (int)" |
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"or the path to a pretrained model config file (str)") |
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class VisualEmbeddings(nn.Module): |
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"""Construct the embeddings from word, position and token_type embeddings. |
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""" |
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def __init__(self, config): |
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super(VisualEmbeddings, self).__init__() |
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self.word_embeddings = nn.Linear(config.vocab_size, config.hidden_size) |
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self.position_embeddings = nn.Embedding(config.max_position_embeddings, config.hidden_size) |
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self.LayerNorm = LayerNorm(config.hidden_size, eps=1e-12) |
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self.dropout = nn.Dropout(config.hidden_dropout_prob) |
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def forward(self, input_embeddings): |
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seq_length = input_embeddings.size(1) |
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position_ids = torch.arange(seq_length, dtype=torch.long, device=input_embeddings.device) |
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position_ids = position_ids.unsqueeze(0).expand(input_embeddings.size(0), -1) |
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words_embeddings = self.word_embeddings(input_embeddings) |
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position_embeddings = self.position_embeddings(position_ids) |
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embeddings = words_embeddings + position_embeddings |
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embeddings = self.LayerNorm(embeddings) |
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embeddings = self.dropout(embeddings) |
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return embeddings |
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class VisualSelfAttention(nn.Module): |
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def __init__(self, config): |
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super(VisualSelfAttention, self).__init__() |
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if config.hidden_size % config.num_attention_heads != 0: |
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raise ValueError( |
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"The hidden size (%d) is not a multiple of the number of attention " |
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"heads (%d)" % (config.hidden_size, config.num_attention_heads)) |
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self.num_attention_heads = config.num_attention_heads |
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self.attention_head_size = int(config.hidden_size / config.num_attention_heads) |
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self.all_head_size = self.num_attention_heads * self.attention_head_size |
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self.query = nn.Linear(config.hidden_size, self.all_head_size) |
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self.key = nn.Linear(config.hidden_size, self.all_head_size) |
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self.value = nn.Linear(config.hidden_size, self.all_head_size) |
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self.dropout = nn.Dropout(config.attention_probs_dropout_prob) |
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def transpose_for_scores(self, x): |
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new_x_shape = x.size()[:-1] + (self.num_attention_heads, self.attention_head_size) |
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x = x.view(*new_x_shape) |
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return x.permute(0, 2, 1, 3) |
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def forward(self, hidden_states, attention_mask): |
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mixed_query_layer = self.query(hidden_states) |
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mixed_key_layer = self.key(hidden_states) |
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mixed_value_layer = self.value(hidden_states) |
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query_layer = self.transpose_for_scores(mixed_query_layer) |
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key_layer = self.transpose_for_scores(mixed_key_layer) |
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value_layer = self.transpose_for_scores(mixed_value_layer) |
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attention_scores = torch.matmul(query_layer, key_layer.transpose(-1, -2)) |
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attention_scores = attention_scores / math.sqrt(self.attention_head_size) |
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attention_scores = attention_scores + attention_mask |
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attention_probs = nn.Softmax(dim=-1)(attention_scores) |
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attention_probs = self.dropout(attention_probs) |
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context_layer = torch.matmul(attention_probs, value_layer) |
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context_layer = context_layer.permute(0, 2, 1, 3).contiguous() |
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new_context_layer_shape = context_layer.size()[:-2] + (self.all_head_size,) |
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context_layer = context_layer.view(*new_context_layer_shape) |
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return context_layer |
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class VisualSelfOutput(nn.Module): |
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def __init__(self, config): |
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super(VisualSelfOutput, self).__init__() |
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self.dense = nn.Linear(config.hidden_size, config.hidden_size) |
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self.LayerNorm = LayerNorm(config.hidden_size, eps=1e-12) |
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self.dropout = nn.Dropout(config.hidden_dropout_prob) |
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def forward(self, hidden_states, input_tensor): |
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hidden_states = self.dense(hidden_states) |
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hidden_states = self.dropout(hidden_states) |
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hidden_states = self.LayerNorm(hidden_states + input_tensor) |
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return hidden_states |
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class VisualAttention(nn.Module): |
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def __init__(self, config): |
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super(VisualAttention, self).__init__() |
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self.self = VisualSelfAttention(config) |
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self.output = VisualSelfOutput(config) |
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def forward(self, input_tensor, attention_mask): |
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self_output = self.self(input_tensor, attention_mask) |
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attention_output = self.output(self_output, input_tensor) |
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return attention_output |
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class VisualIntermediate(nn.Module): |
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def __init__(self, config): |
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super(VisualIntermediate, self).__init__() |
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self.dense = nn.Linear(config.hidden_size, config.intermediate_size) |
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self.intermediate_act_fn = ACT2FN[config.hidden_act] \ |
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if isinstance(config.hidden_act, str) else config.hidden_act |
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def forward(self, hidden_states): |
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hidden_states = self.dense(hidden_states) |
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hidden_states = self.intermediate_act_fn(hidden_states) |
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return hidden_states |
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class VisualOutput(nn.Module): |
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def __init__(self, config): |
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super(VisualOutput, self).__init__() |
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self.dense = nn.Linear(config.intermediate_size, config.hidden_size) |
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self.LayerNorm = LayerNorm(config.hidden_size, eps=1e-12) |
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self.dropout = nn.Dropout(config.hidden_dropout_prob) |
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def forward(self, hidden_states, input_tensor): |
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hidden_states = self.dense(hidden_states) |
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hidden_states = self.dropout(hidden_states) |
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hidden_states = self.LayerNorm(hidden_states + input_tensor) |
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return hidden_states |
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class VisualLayer(nn.Module): |
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def __init__(self, config): |
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super(VisualLayer, self).__init__() |
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self.attention = VisualAttention(config) |
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self.intermediate = VisualIntermediate(config) |
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self.output = VisualOutput(config) |
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def forward(self, hidden_states, attention_mask): |
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attention_output = self.attention(hidden_states, attention_mask) |
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intermediate_output = self.intermediate(attention_output) |
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layer_output = self.output(intermediate_output, attention_output) |
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return layer_output |
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class VisualEncoder(nn.Module): |
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def __init__(self, config): |
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super(VisualEncoder, self).__init__() |
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layer = VisualLayer(config) |
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self.layer = nn.ModuleList([copy.deepcopy(layer) for _ in range(config.num_hidden_layers)]) |
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def forward(self, hidden_states, attention_mask, output_all_encoded_layers=True): |
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all_encoder_layers = [] |
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for layer_module in self.layer: |
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hidden_states = layer_module(hidden_states, attention_mask) |
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if output_all_encoded_layers: |
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all_encoder_layers.append(hidden_states) |
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if not output_all_encoded_layers: |
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all_encoder_layers.append(hidden_states) |
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return all_encoder_layers |
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class VisualPooler(nn.Module): |
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def __init__(self, config): |
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super(VisualPooler, self).__init__() |
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self.dense = nn.Linear(config.hidden_size, config.hidden_size) |
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self.activation = nn.Tanh() |
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def forward(self, hidden_states): |
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first_token_tensor = hidden_states[:, 0] |
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pooled_output = self.dense(first_token_tensor) |
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pooled_output = self.activation(pooled_output) |
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return pooled_output |
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class VisualPredictionHeadTransform(nn.Module): |
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def __init__(self, config): |
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super(VisualPredictionHeadTransform, self).__init__() |
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self.dense = nn.Linear(config.hidden_size, config.hidden_size) |
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self.transform_act_fn = ACT2FN[config.hidden_act] \ |
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if isinstance(config.hidden_act, str) else config.hidden_act |
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self.LayerNorm = LayerNorm(config.hidden_size, eps=1e-12) |
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def forward(self, hidden_states): |
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hidden_states = self.dense(hidden_states) |
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hidden_states = self.transform_act_fn(hidden_states) |
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hidden_states = self.LayerNorm(hidden_states) |
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return hidden_states |
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class VisualLMPredictionHead(nn.Module): |
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def __init__(self, config, visual_model_embedding_weights): |
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super(VisualLMPredictionHead, self).__init__() |
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self.transform = VisualPredictionHeadTransform(config) |
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self.weight = visual_model_embedding_weights |
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self.bias = nn.Parameter(torch.zeros(visual_model_embedding_weights.size(1))) |
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def forward(self, hidden_states): |
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hidden_states = self.transform(hidden_states) |
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hidden_states = hidden_states.matmul(self.weight) + self.bias |
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return hidden_states |
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class VisualOnlyMLMHead(nn.Module): |
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def __init__(self, config, visual_model_embedding_weights): |
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super(VisualOnlyMLMHead, self).__init__() |
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self.predictions = VisualLMPredictionHead(config, visual_model_embedding_weights) |
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def forward(self, sequence_output): |
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prediction_scores = self.predictions(sequence_output) |
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return prediction_scores |
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class VisualOnlyNSPHead(nn.Module): |
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def __init__(self, config): |
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super(VisualOnlyNSPHead, self).__init__() |
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self.seq_relationship = nn.Linear(config.hidden_size, 2) |
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def forward(self, pooled_output): |
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seq_relationship_score = self.seq_relationship(pooled_output) |
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return seq_relationship_score |
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class VisualPreTrainingHeads(nn.Module): |
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def __init__(self, config, visual_model_embedding_weights): |
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super(VisualPreTrainingHeads, self).__init__() |
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self.predictions = VisualLMPredictionHead(config, visual_model_embedding_weights) |
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self.seq_relationship = nn.Linear(config.hidden_size, 2) |
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def forward(self, sequence_output, pooled_output): |
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prediction_scores = self.predictions(sequence_output) |
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seq_relationship_score = self.seq_relationship(pooled_output) |
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return prediction_scores, seq_relationship_score |
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class VisualModel(PreTrainedModel): |
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"""Visual model ("Bidirectional Embedding Representations from a Transformer"). |
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Params: |
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config: a VisualConfig class instance with the configuration to build a new model |
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Inputs: |
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`type`: a str, indicates which masking will be used in the attention, choice from [`bi`, `seq`, `gen`] |
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`input_ids`: a torch.LongTensor of shape [batch_size, sequence_length] |
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with the word token indices in the vocabulary(see the tokens preprocessing logic in the scripts |
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`extract_features.py`, `run_classifier.py` and `run_squad.py`) |
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`token_type_ids`: an optional torch.LongTensor of shape [batch_size, sequence_length] with the token |
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types indices selected in [0, 1]. Type 0 corresponds to a `sentence A` and type 1 corresponds to |
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a `sentence B` token (see paper for more details). |
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`attention_mask`: an optional torch.LongTensor of shape [batch_size, sequence_length] with indices |
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selected in [0, 1]. It's a mask to be used if the input sequence length is smaller than the max |
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input sequence length in the current batch. It's the mask that we typically use for attention when |
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a batch has varying length sentences. |
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`output_all_encoded_layers`: boolean which controls the content of the `encoded_layers` output as described below. Default: `True`. |
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Outputs: Tuple of (encoded_layers, pooled_output) |
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`encoded_layers`: controled by `output_all_encoded_layers` argument: |
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- `output_all_encoded_layers=True`: outputs a list of the full sequences of encoded-hidden-states at the end |
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|
of each attention block (i.e. 12 full sequences for Visual-base, 24 for Visual-large), each |
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encoded-hidden-state is a torch.FloatTensor of size [batch_size, sequence_length, hidden_size], |
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- `output_all_encoded_layers=False`: outputs only the full sequence of hidden-states corresponding |
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to the last attention block of shape [batch_size, sequence_length, hidden_size], |
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`pooled_output`: a torch.FloatTensor of size [batch_size, hidden_size] which is the output of a |
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|
classifier pretrained on top of the hidden state associated to the first character of the |
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|
input (`CLF`) to train on the Next-Sentence task (see 's paper). |
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|
Example usage: |
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|
```python |
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# Already been converted into WordPiece token ids |
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|
input_ids = torch.LongTensor([[31, 51, 99], [15, 5, 0]]) |
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input_mask = torch.LongTensor([[1, 1, 1], [1, 1, 0]]) |
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config = modeling.VisualConfig(vocab_size_or_config_json_file=4096, hidden_size=768, |
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num_hidden_layers=12, num_attention_heads=12, intermediate_size=3072) |
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model = modeling.VisualModel(config=config) |
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all_encoder_layers, pooled_output = model(video, video_mask) |
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``` |
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|
""" |
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def __init__(self, config): |
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super(VisualModel, self).__init__(config) |
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|
self.embeddings = VisualEmbeddings(config) |
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|
self.encoder = VisualEncoder(config) |
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|
self.pooler = VisualPooler(config) |
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self.apply(self.init_weights) |
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def forward(self, video, attention_mask=None, output_all_encoded_layers=True): |
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if attention_mask is None: |
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attention_mask = torch.ones(video.size(0), video.size(1)) |
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extended_attention_mask = attention_mask.unsqueeze(1).unsqueeze(2) |
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extended_attention_mask = extended_attention_mask.to(dtype=self.dtype) |
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extended_attention_mask = (1.0 - extended_attention_mask) * -10000.0 |
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embedding_output = self.embeddings(video) |
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encoded_layers = self.encoder(embedding_output, |
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extended_attention_mask, |
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output_all_encoded_layers=output_all_encoded_layers) |
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sequence_output = encoded_layers[-1] |
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pooled_output = self.pooler(sequence_output) |
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|
if not output_all_encoded_layers: |
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|
encoded_layers = encoded_layers[-1] |
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return encoded_layers, pooled_output |