809 lines
39 KiB
Python
809 lines
39 KiB
Python
from __future__ import absolute_import, division, print_function, unicode_literals
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import logging
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import math
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import os
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import torch
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from torch import nn
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from torch.nn.modules.loss import _Loss
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import torch.nn.functional as F
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from transformers import BertConfig
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from transformers.modeling_bert import \
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BertPreTrainedModel, BertSelfOutput, BertIntermediate, BertOutput, BertPredictionHeadTransform
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from transformers.modeling_roberta import ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP
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from transformers.modeling_bert import BERT_PRETRAINED_MODEL_ARCHIVE_MAP
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from transformers.modeling_xlm_roberta import XLM_ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP
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from s2s_ft.config import BertForSeq2SeqConfig
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from s2s_ft.convert_state_dict import get_checkpoint_from_transformer_cache, state_dict_convert
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logger = logging.getLogger(__name__)
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BertLayerNorm = torch.nn.LayerNorm
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UNILM_PRETRAINED_MODEL_ARCHIVE_MAP = {
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'unilm-base-cased': "https://conversationhub.blob.core.windows.net/beit-share-public/ckpt/unilm1-base-cased.bin?sv=2021-10-04&st=2023-06-08T11%3A16%3A02Z&se=2033-06-09T11%3A16%3A00Z&sr=c&sp=r&sig=N4pfCVmSeq4L4tS8QbrFVsX6f6q844eft8xSuXdxU48%3D",
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'unilm-large-cased': "https://conversationhub.blob.core.windows.net/beit-share-public/ckpt/unilm1-large-cased.bin?sv=2021-10-04&st=2023-06-08T11%3A16%3A02Z&se=2033-06-09T11%3A16%3A00Z&sr=c&sp=r&sig=N4pfCVmSeq4L4tS8QbrFVsX6f6q844eft8xSuXdxU48%3D",
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'unilm1-base-cased': "https://conversationhub.blob.core.windows.net/beit-share-public/ckpt/unilm1-base-cased.bin?sv=2021-10-04&st=2023-06-08T11%3A16%3A02Z&se=2033-06-09T11%3A16%3A00Z&sr=c&sp=r&sig=N4pfCVmSeq4L4tS8QbrFVsX6f6q844eft8xSuXdxU48%3D",
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'unilm1-large-cased': "https://conversationhub.blob.core.windows.net/beit-share-public/ckpt/unilm1-large-cased.bin?sv=2021-10-04&st=2023-06-08T11%3A16%3A02Z&se=2033-06-09T11%3A16%3A00Z&sr=c&sp=r&sig=N4pfCVmSeq4L4tS8QbrFVsX6f6q844eft8xSuXdxU48%3D",
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'unilm1.2-base-uncased': "https://conversationhub.blob.core.windows.net/beit-share-public/ckpt/unilm1.2-base-uncased.bin?sv=2021-10-04&st=2023-06-08T11%3A16%3A02Z&se=2033-06-09T11%3A16%3A00Z&sr=c&sp=r&sig=N4pfCVmSeq4L4tS8QbrFVsX6f6q844eft8xSuXdxU48%3D"
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}
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MINILM_PRETRAINED_MODEL_ARCHIVE_MAP = {
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'minilm-l12-h384-uncased': "https://conversationhub.blob.core.windows.net/beit-share-public/ckpt/minilm-l12-h384-uncased.bin?sv=2021-10-04&st=2023-06-08T11%3A16%3A02Z&se=2033-06-09T11%3A16%3A00Z&sr=c&sp=r&sig=N4pfCVmSeq4L4tS8QbrFVsX6f6q844eft8xSuXdxU48%3D",
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}
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LAYOUTLM_PRETRAINED_MODEL_ARCHIVE_MAP = {
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'layoutlm-base-uncased': 'https://huggingface.co/microsoft/layoutlm-base-uncased/resolve/main/pytorch_model.bin',
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'layoutlm-large-uncased': 'https://huggingface.co/microsoft/layoutlm-large-uncased/resolve/main/pytorch_model.bin'
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}
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LAYOUTLM_PRETRAINED_CONFIG_ARCHIVE_MAP = {
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'layoutlm-base-uncased': 'https://huggingface.co/microsoft/layoutlm-base-uncased/resolve/main/config.json',
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'layoutlm-large-uncased': 'https://huggingface.co/microsoft/layoutlm-large-uncased/resolve/main/config.json'
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}
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class LayoutlmConfig(BertConfig):
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pretrained_config_archive_map = LAYOUTLM_PRETRAINED_CONFIG_ARCHIVE_MAP
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model_type = "bert"
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def __init__(self, max_2d_position_embeddings=1024, **kwargs):
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super().__init__(**kwargs)
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self.max_2d_position_embeddings = max_2d_position_embeddings
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class BertPreTrainedForSeq2SeqModel(BertPreTrainedModel):
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""" An abstract class to handle weights initialization and
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a simple interface for dowloading and loading pretrained models.
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"""
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config_class = BertForSeq2SeqConfig
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supported_convert_pretrained_model_archive_map = {
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"bert": BERT_PRETRAINED_MODEL_ARCHIVE_MAP,
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"roberta": ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP,
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"xlm-roberta": XLM_ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP,
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"unilm": UNILM_PRETRAINED_MODEL_ARCHIVE_MAP,
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"minilm": MINILM_PRETRAINED_MODEL_ARCHIVE_MAP,
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"layoutlm": LAYOUTLM_PRETRAINED_MODEL_ARCHIVE_MAP,
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}
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base_model_prefix = "bert_for_seq2seq"
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pretrained_model_archive_map = {
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**ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP,
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**XLM_ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP,
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**BERT_PRETRAINED_MODEL_ARCHIVE_MAP,
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**UNILM_PRETRAINED_MODEL_ARCHIVE_MAP,
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**MINILM_PRETRAINED_MODEL_ARCHIVE_MAP,
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**LAYOUTLM_PRETRAINED_MODEL_ARCHIVE_MAP,
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}
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def _init_weights(self, module):
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""" Initialize the weights """
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if isinstance(module, (nn.Linear, nn.Embedding)):
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# Slightly different from the TF version which uses truncated_normal for initialization
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# cf https://github.com/pytorch/pytorch/pull/5617
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module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
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elif isinstance(module, BertLayerNorm):
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module.bias.data.zero_()
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module.weight.data.fill_(1.0)
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if isinstance(module, nn.Linear) and module.bias is not None:
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module.bias.data.zero_()
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@classmethod
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def from_pretrained(cls, pretrained_model_name_or_path, reuse_position_embedding=None,
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*model_args, **kwargs):
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model_type = kwargs.pop('model_type', None)
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if model_type is not None and "state_dict" not in kwargs:
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if model_type in cls.supported_convert_pretrained_model_archive_map:
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pretrained_model_archive_map = cls.supported_convert_pretrained_model_archive_map[model_type]
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if pretrained_model_name_or_path in pretrained_model_archive_map:
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state_dict = get_checkpoint_from_transformer_cache(
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archive_file=pretrained_model_archive_map[pretrained_model_name_or_path],
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pretrained_model_name_or_path=pretrained_model_name_or_path,
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pretrained_model_archive_map=pretrained_model_archive_map,
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cache_dir=kwargs.get("cache_dir", None), force_download=kwargs.get("force_download", None),
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proxies=kwargs.get("proxies", None), resume_download=kwargs.get("resume_download", None),
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)
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state_dict = state_dict_convert[model_type](state_dict)
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kwargs["state_dict"] = state_dict
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elif os.path.isfile(pretrained_model_name_or_path):
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kwargs["state_dict"] = torch.load(pretrained_model_name_or_path, map_location='cpu')
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if kwargs["state_dict"] is None:
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logger.info("s2s-ft does't support the model !")
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raise NotImplementedError()
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config = kwargs["config"]
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state_dict = kwargs["state_dict"]
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# initialize new position embeddings (From Microsoft/UniLM)
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_k = 'bert.embeddings.position_embeddings.weight'
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if _k in state_dict:
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if config.max_position_embeddings > state_dict[_k].shape[0]:
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logger.info("Resize > position embeddings !")
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old_vocab_size = state_dict[_k].shape[0]
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new_position_embedding = state_dict[_k].data.new_tensor(torch.ones(
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size=(config.max_position_embeddings, state_dict[_k].shape[1])), dtype=torch.float)
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new_position_embedding = nn.Parameter(data=new_position_embedding, requires_grad=True)
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new_position_embedding.data.normal_(mean=0.0, std=config.initializer_range)
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max_range = config.max_position_embeddings if reuse_position_embedding else old_vocab_size
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shift = 0
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while shift < max_range:
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delta = min(old_vocab_size, max_range - shift)
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new_position_embedding.data[shift: shift + delta, :] = state_dict[_k][:delta, :]
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logger.info(" CP [%d ~ %d] into [%d ~ %d] " % (0, delta, shift, shift + delta))
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shift += delta
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state_dict[_k] = new_position_embedding.data
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del new_position_embedding
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elif config.max_position_embeddings < state_dict[_k].shape[0]:
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logger.info("Resize < position embeddings !")
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old_vocab_size = state_dict[_k].shape[0]
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new_position_embedding = state_dict[_k].data.new_tensor(torch.ones(
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size=(config.max_position_embeddings, state_dict[_k].shape[1])), dtype=torch.float)
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new_position_embedding = nn.Parameter(data=new_position_embedding, requires_grad=True)
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new_position_embedding.data.normal_(mean=0.0, std=config.initializer_range)
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new_position_embedding.data.copy_(state_dict[_k][:config.max_position_embeddings, :])
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state_dict[_k] = new_position_embedding.data
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del new_position_embedding
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return super().from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
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class BertEmbeddings(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(BertEmbeddings, self).__init__()
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self.word_embeddings = nn.Embedding(config.vocab_size, config.hidden_size, padding_idx=0)
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self.position_embeddings = nn.Embedding(config.max_position_embeddings, config.hidden_size)
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if config.type_vocab_size > 0:
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self.token_type_embeddings = nn.Embedding(config.type_vocab_size, config.hidden_size)
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else:
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self.token_type_embeddings = None
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# self.LayerNorm is not snake-cased to stick with TensorFlow model variable name and be able to load
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# any TensorFlow checkpoint file
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self.LayerNorm = BertLayerNorm(config.hidden_size, eps=config.layer_norm_eps)
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self.dropout = nn.Dropout(config.hidden_dropout_prob)
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def forward(self, input_ids=None, token_type_ids=None, position_ids=None, inputs_embeds=None):
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if input_ids is not None:
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input_shape = input_ids.size()
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else:
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input_shape = inputs_embeds.size()[:-1]
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seq_length = input_shape[1]
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device = input_ids.device if input_ids is not None else inputs_embeds.device
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if position_ids is None:
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position_ids = torch.arange(seq_length, dtype=torch.long, device=device)
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position_ids = position_ids.unsqueeze(0).expand(input_shape)
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if token_type_ids is None:
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token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=device)
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if inputs_embeds is None:
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inputs_embeds = self.word_embeddings(input_ids)
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position_embeddings = self.position_embeddings(position_ids)
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embeddings = inputs_embeds + position_embeddings
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if self.token_type_embeddings:
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embeddings = embeddings + self.token_type_embeddings(token_type_ids)
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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 LayoutlmEmbeddings(nn.Module):
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def __init__(self, config):
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super(LayoutlmEmbeddings, self).__init__()
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self.only_layout_flag = config.layoutlm_only_layout
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if not config.layoutlm_only_layout:
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self.word_embeddings = nn.Embedding(
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config.vocab_size, config.hidden_size, padding_idx=0
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)
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else:
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self.word_embeddings = None
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self.position_embeddings = nn.Embedding(
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config.max_position_embeddings, config.hidden_size
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)
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self.x_position_embeddings = nn.Embedding(
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config.max_2d_position_embeddings, config.hidden_size
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)
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self.y_position_embeddings = nn.Embedding(
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config.max_2d_position_embeddings, config.hidden_size
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)
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self.h_position_embeddings = nn.Embedding(
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config.max_2d_position_embeddings, config.hidden_size
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)
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self.w_position_embeddings = nn.Embedding(
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config.max_2d_position_embeddings, config.hidden_size
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)
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if config.type_vocab_size > 0:
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self.token_type_embeddings = nn.Embedding(config.type_vocab_size, config.hidden_size)
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else:
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self.token_type_embeddings = None
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# self.LayerNorm is not snake-cased to stick with TensorFlow model variable name and be able to load
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# any TensorFlow checkpoint file
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self.LayerNorm = BertLayerNorm(config.hidden_size, eps=config.layer_norm_eps)
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self.dropout = nn.Dropout(config.hidden_dropout_prob)
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def forward(
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self,
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input_ids,
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bbox,
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token_type_ids=None,
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position_ids=None,
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inputs_embeds=None,
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):
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seq_length = input_ids.size(1)
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if position_ids is None:
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position_ids = torch.arange(
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seq_length, dtype=torch.long, device=input_ids.device
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)
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position_ids = position_ids.unsqueeze(0).expand_as(input_ids)
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if token_type_ids is None:
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token_type_ids = torch.zeros_like(input_ids)
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left_position_embeddings = self.x_position_embeddings(bbox[:, :, 0])
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upper_position_embeddings = self.y_position_embeddings(bbox[:, :, 1])
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right_position_embeddings = self.x_position_embeddings(bbox[:, :, 2])
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lower_position_embeddings = self.y_position_embeddings(bbox[:, :, 3])
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h_position_embeddings = self.h_position_embeddings(
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bbox[:, :, 3] - bbox[:, :, 1]
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)
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w_position_embeddings = self.w_position_embeddings(
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bbox[:, :, 2] - bbox[:, :, 0]
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)
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position_embeddings = self.position_embeddings(position_ids)
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embeddings = (
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left_position_embeddings
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+ upper_position_embeddings
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+ right_position_embeddings
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+ lower_position_embeddings
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+ h_position_embeddings
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+ w_position_embeddings
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+ position_embeddings
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# + token_type_embeddings
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)
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if not self.only_layout_flag:
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words_embeddings = self.word_embeddings(input_ids)
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embeddings = embeddings + words_embeddings
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if self.token_type_embeddings:
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embeddings = embeddings + self.token_type_embeddings(token_type_ids)
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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 BertSelfAttention(nn.Module):
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def __init__(self, config):
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super(BertSelfAttention, 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.output_attentions = config.output_attentions
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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 multi_head_attention(self, query, key, value, attention_mask):
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query_layer = self.transpose_for_scores(query)
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key_layer = self.transpose_for_scores(key)
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value_layer = self.transpose_for_scores(value)
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# Take the dot product between "query" and "key" to get the raw attention scores.
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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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if attention_mask is not None:
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# Apply the attention mask is (precomputed for all layers in BertModel forward() function)
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attention_scores = attention_scores + attention_mask
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# Normalize the attention scores to probabilities.
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attention_probs = nn.Softmax(dim=-1)(attention_scores)
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# This is actually dropping out entire tokens to attend to, which might
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# seem a bit unusual, but is taken from the original Transformer paper.
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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, attention_probs) if self.output_attentions else (context_layer,)
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def forward(self, hidden_states, attention_mask=None, encoder_hidden_states=None, split_lengths=None):
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mixed_query_layer = self.query(hidden_states)
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if split_lengths:
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assert not self.output_attentions
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# If this is instantiated as a cross-attention module, the keys
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# and values come from an encoder; the attention mask needs to be
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# such that the encoder's padding tokens are not attended to.
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if encoder_hidden_states is not None:
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mixed_key_layer = self.key(encoder_hidden_states)
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mixed_value_layer = self.value(encoder_hidden_states)
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else:
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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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if split_lengths:
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query_parts = torch.split(mixed_query_layer, split_lengths, dim=1)
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key_parts = torch.split(mixed_key_layer, split_lengths, dim=1)
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value_parts = torch.split(mixed_value_layer, split_lengths, dim=1)
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key = None
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value = None
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outputs = []
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sum_length = 0
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for (query, _key, _value, part_length) in zip(query_parts, key_parts, value_parts, split_lengths):
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key = _key if key is None else torch.cat((key, _key), dim=1)
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value = _value if value is None else torch.cat((value, _value), dim=1)
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sum_length += part_length
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outputs.append(self.multi_head_attention(
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query, key, value, attention_mask[:, :, sum_length - part_length: sum_length, :sum_length]
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)[0])
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outputs = (torch.cat(outputs, dim=1), )
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else:
|
|
outputs = self.multi_head_attention(
|
|
mixed_query_layer, mixed_key_layer, mixed_value_layer, attention_mask)
|
|
return outputs
|
|
|
|
|
|
class BertAttention(nn.Module):
|
|
def __init__(self, config):
|
|
super(BertAttention, self).__init__()
|
|
self.self = BertSelfAttention(config)
|
|
self.output = BertSelfOutput(config)
|
|
|
|
def forward(self, hidden_states, attention_mask=None, encoder_hidden_states=None, split_lengths=None):
|
|
self_outputs = self.self(
|
|
hidden_states, attention_mask=attention_mask,
|
|
encoder_hidden_states=encoder_hidden_states, split_lengths=split_lengths)
|
|
attention_output = self.output(self_outputs[0], hidden_states)
|
|
outputs = (attention_output,) + self_outputs[1:] # add attentions if we output them
|
|
return outputs
|
|
|
|
|
|
class BertLayer(nn.Module):
|
|
def __init__(self, config):
|
|
super(BertLayer, self).__init__()
|
|
self.attention = BertAttention(config)
|
|
self.intermediate = BertIntermediate(config)
|
|
self.output = BertOutput(config)
|
|
|
|
def forward(self, hidden_states, attention_mask=None, split_lengths=None):
|
|
self_attention_outputs = self.attention(
|
|
hidden_states, attention_mask, split_lengths=split_lengths)
|
|
attention_output = self_attention_outputs[0]
|
|
|
|
intermediate_output = self.intermediate(attention_output)
|
|
layer_output = self.output(intermediate_output, attention_output)
|
|
outputs = (layer_output,) + self_attention_outputs[1:]
|
|
return outputs
|
|
|
|
|
|
class BertEncoder(nn.Module):
|
|
def __init__(self, config):
|
|
super(BertEncoder, self).__init__()
|
|
self.output_attentions = config.output_attentions
|
|
self.output_hidden_states = config.output_hidden_states
|
|
self.layer = nn.ModuleList([BertLayer(config) for _ in range(config.num_hidden_layers)])
|
|
|
|
def forward(self, hidden_states, attention_mask=None, split_lengths=None):
|
|
all_hidden_states = ()
|
|
all_attentions = ()
|
|
for i, layer_module in enumerate(self.layer):
|
|
if self.output_hidden_states:
|
|
all_hidden_states = all_hidden_states + (hidden_states,)
|
|
|
|
layer_outputs = layer_module(hidden_states, attention_mask, split_lengths=split_lengths)
|
|
hidden_states = layer_outputs[0]
|
|
|
|
if self.output_attentions:
|
|
all_attentions = all_attentions + (layer_outputs[1],)
|
|
|
|
# Add last layer
|
|
if self.output_hidden_states:
|
|
all_hidden_states = all_hidden_states + (hidden_states,)
|
|
|
|
outputs = (hidden_states,)
|
|
if self.output_hidden_states:
|
|
outputs = outputs + (all_hidden_states,)
|
|
if self.output_attentions:
|
|
outputs = outputs + (all_attentions,)
|
|
return outputs # last-layer hidden state, (all hidden states), (all attentions)
|
|
|
|
|
|
class BertModel(BertPreTrainedForSeq2SeqModel):
|
|
r"""
|
|
Outputs: `Tuple` comprising various elements depending on the configuration (config) and inputs:
|
|
**last_hidden_state**: ``torch.FloatTensor`` of shape ``(batch_size, sequence_length, hidden_size)``
|
|
Sequence of hidden-states at the output of the last layer of the model.
|
|
**pooler_output**: ``torch.FloatTensor`` of shape ``(batch_size, hidden_size)``
|
|
Last layer hidden-state of the first token of the sequence (classification token)
|
|
further processed by a Linear layer and a Tanh activation function. The Linear
|
|
layer weights are trained from the next sentence prediction (classification)
|
|
objective during Bert pretraining. This output is usually *not* a good summary
|
|
of the semantic content of the input, you're often better with averaging or pooling
|
|
the sequence of hidden-states for the whole input sequence.
|
|
**hidden_states**: (`optional`, returned when ``config.output_hidden_states=True``)
|
|
list of ``torch.FloatTensor`` (one for the output of each layer + the output of the embeddings)
|
|
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**: (`optional`, returned when ``config.output_attentions=True``)
|
|
list 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.
|
|
|
|
Examples::
|
|
|
|
tokenizer = BertTokenizer.from_pretrained('bert-base-uncased')
|
|
model = BertModel.from_pretrained('bert-base-uncased')
|
|
input_ids = torch.tensor(tokenizer.encode("Hello, my dog is cute", add_special_tokens=True)).unsqueeze(0) # Batch size 1
|
|
outputs = model(input_ids)
|
|
last_hidden_states = outputs[0] # The last hidden-state is the first element of the output tuple
|
|
|
|
"""
|
|
def __init__(self, config):
|
|
super(BertModel, self).__init__(config)
|
|
self.config = config
|
|
|
|
self.embeddings = BertEmbeddings(config)
|
|
self.encoder = BertEncoder(config)
|
|
|
|
def forward(self, input_ids=None, attention_mask=None, token_type_ids=None,
|
|
position_ids=None, inputs_embeds=None, split_lengths=None, return_emb=False):
|
|
if input_ids is not None and inputs_embeds is not None:
|
|
raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time")
|
|
elif input_ids is not None:
|
|
input_shape = input_ids.size()
|
|
elif inputs_embeds is not None:
|
|
input_shape = inputs_embeds.size()[:-1]
|
|
else:
|
|
raise ValueError("You have to specify either input_ids or inputs_embeds")
|
|
|
|
device = input_ids.device if input_ids is not None else inputs_embeds.device
|
|
|
|
if attention_mask is None:
|
|
attention_mask = torch.ones(input_shape, device=device)
|
|
|
|
# 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.
|
|
if attention_mask.dim() == 3:
|
|
extended_attention_mask = attention_mask[:, None, :, :]
|
|
|
|
# Provided a padding mask of dimensions [batch_size, seq_length]
|
|
# - if the model is a decoder, apply a causal mask in addition to the padding mask
|
|
# - if the model is an encoder, make the mask broadcastable to [batch_size, num_heads, seq_length, seq_length]
|
|
if attention_mask.dim() == 2:
|
|
extended_attention_mask = attention_mask[:, None, None, :]
|
|
|
|
# Since attention_mask is 1.0 for positions we want to attend and 0.0 for
|
|
# masked positions, this operation will create a tensor which is 0.0 for
|
|
# positions we want to attend and -10000.0 for masked positions.
|
|
# Since we are adding it to the raw scores before the softmax, this is
|
|
# effectively the same as removing these entirely.
|
|
extended_attention_mask = extended_attention_mask.to(dtype=next(self.parameters()).dtype) # fp16 compatibility
|
|
extended_attention_mask = (1.0 - extended_attention_mask) * -10000.0
|
|
|
|
embedding_output = self.embeddings(
|
|
input_ids=input_ids, position_ids=position_ids, token_type_ids=token_type_ids, inputs_embeds=inputs_embeds)
|
|
encoder_outputs = self.encoder(
|
|
embedding_output, attention_mask=extended_attention_mask, split_lengths=split_lengths)
|
|
sequence_output = encoder_outputs[0]
|
|
|
|
outputs = (sequence_output, ) + encoder_outputs[1:] # add hidden_states and attentions if they are here
|
|
|
|
if return_emb:
|
|
outputs += (embedding_output,)
|
|
|
|
return outputs # sequence_output, pooled_output, (hidden_states), (attentions)
|
|
|
|
|
|
class LayoutlmModel(BertPreTrainedForSeq2SeqModel):
|
|
r"""
|
|
Outputs: `Tuple` comprising various elements depending on the configuration (config) and inputs:
|
|
**last_hidden_state**: ``torch.FloatTensor`` of shape ``(batch_size, sequence_length, hidden_size)``
|
|
Sequence of hidden-states at the output of the last layer of the model.
|
|
**pooler_output**: ``torch.FloatTensor`` of shape ``(batch_size, hidden_size)``
|
|
Last layer hidden-state of the first token of the sequence (classification token)
|
|
further processed by a Linear layer and a Tanh activation function. The Linear
|
|
layer weights are trained from the next sentence prediction (classification)
|
|
objective during Bert pretraining. This output is usually *not* a good summary
|
|
of the semantic content of the input, you're often better with averaging or pooling
|
|
the sequence of hidden-states for the whole input sequence.
|
|
**hidden_states**: (`optional`, returned when ``config.output_hidden_states=True``)
|
|
list of ``torch.FloatTensor`` (one for the output of each layer + the output of the embeddings)
|
|
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**: (`optional`, returned when ``config.output_attentions=True``)
|
|
list 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.
|
|
|
|
Examples::
|
|
|
|
tokenizer = BertTokenizer.from_pretrained('bert-base-uncased')
|
|
model = BertModel.from_pretrained('bert-base-uncased')
|
|
input_ids = torch.tensor(tokenizer.encode("Hello, my dog is cute", add_special_tokens=True)).unsqueeze(0) # Batch size 1
|
|
outputs = model(input_ids)
|
|
last_hidden_states = outputs[0] # The last hidden-state is the first element of the output tuple
|
|
|
|
"""
|
|
def __init__(self, config):
|
|
super(LayoutlmModel, self).__init__(config)
|
|
self.config = config
|
|
|
|
self.embeddings = LayoutlmEmbeddings(config)
|
|
self.encoder = BertEncoder(config)
|
|
|
|
def forward(self,
|
|
input_ids=None,
|
|
bbox=None,
|
|
attention_mask=None,
|
|
token_type_ids=None,
|
|
position_ids=None,
|
|
inputs_embeds=None,
|
|
split_lengths=None,
|
|
return_emb=False):
|
|
|
|
if input_ids is not None and inputs_embeds is not None:
|
|
raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time")
|
|
elif input_ids is not None:
|
|
input_shape = input_ids.size()
|
|
elif inputs_embeds is not None:
|
|
input_shape = inputs_embeds.size()[:-1]
|
|
else:
|
|
raise ValueError("You have to specify either input_ids or inputs_embeds")
|
|
|
|
device = input_ids.device if input_ids is not None else inputs_embeds.device
|
|
|
|
if attention_mask is None:
|
|
attention_mask = torch.ones(input_shape, device=device)
|
|
|
|
# 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.
|
|
if attention_mask.dim() == 3:
|
|
extended_attention_mask = attention_mask[:, None, :, :]
|
|
|
|
# Provided a padding mask of dimensions [batch_size, seq_length]
|
|
# - if the model is a decoder, apply a causal mask in addition to the padding mask
|
|
# - if the model is an encoder, make the mask broadcastable to [batch_size, num_heads, seq_length, seq_length]
|
|
if attention_mask.dim() == 2:
|
|
extended_attention_mask = attention_mask[:, None, None, :]
|
|
|
|
# Since attention_mask is 1.0 for positions we want to attend and 0.0 for
|
|
# masked positions, this operation will create a tensor which is 0.0 for
|
|
# positions we want to attend and -10000.0 for masked positions.
|
|
# Since we are adding it to the raw scores before the softmax, this is
|
|
# effectively the same as removing these entirely.
|
|
extended_attention_mask = extended_attention_mask.to(dtype=next(self.parameters()).dtype) # fp16 compatibility
|
|
extended_attention_mask = (1.0 - extended_attention_mask) * -10000.0
|
|
|
|
# embedding_output = self.embeddings(
|
|
# input_ids=input_ids, position_ids=position_ids, token_type_ids=token_type_ids, inputs_embeds=inputs_embeds)
|
|
embedding_output = self.embeddings(
|
|
input_ids, bbox, position_ids=position_ids, token_type_ids=token_type_ids
|
|
)
|
|
encoder_outputs = self.encoder(
|
|
embedding_output, attention_mask=extended_attention_mask, split_lengths=split_lengths)
|
|
sequence_output = encoder_outputs[0]
|
|
|
|
outputs = (sequence_output, ) + encoder_outputs[1:] # add hidden_states and attentions if they are here
|
|
|
|
if return_emb:
|
|
outputs += (embedding_output,)
|
|
|
|
return outputs # sequence_output, pooled_output, (hidden_states), (attentions)
|
|
|
|
|
|
class LabelSmoothingLoss(_Loss):
|
|
"""
|
|
With label smoothing,
|
|
KL-divergence between q_{smoothed ground truth prob.}(w)
|
|
and p_{prob. computed by model}(w) is minimized.
|
|
"""
|
|
|
|
def __init__(self, label_smoothing=0, tgt_size=0, ignore_index=0, size_average=None, reduce=None, reduction='mean'):
|
|
assert 0.0 < label_smoothing <= 1.0
|
|
self.ignore_index = ignore_index
|
|
super(LabelSmoothingLoss, self).__init__(
|
|
size_average=size_average, reduce=reduce, reduction=reduction)
|
|
|
|
assert label_smoothing > 0
|
|
assert tgt_size > 0
|
|
|
|
smoothing_value = label_smoothing / (tgt_size - 2)
|
|
one_hot = torch.full((tgt_size,), smoothing_value)
|
|
one_hot[self.ignore_index] = 0
|
|
self.register_buffer('one_hot', one_hot.unsqueeze(0))
|
|
self.confidence = 1.0 - label_smoothing
|
|
self.tgt_size = tgt_size
|
|
|
|
def forward(self, output, target):
|
|
"""
|
|
output (FloatTensor): batch_size * num_pos * n_classes
|
|
target (LongTensor): batch_size * num_pos
|
|
"""
|
|
assert self.tgt_size == output.size(2)
|
|
batch_size, num_pos = target.size(0), target.size(1)
|
|
output = output.view(-1, self.tgt_size)
|
|
target = target.view(-1)
|
|
model_prob = self.one_hot.float().repeat(target.size(0), 1)
|
|
model_prob.scatter_(1, target.unsqueeze(1), self.confidence)
|
|
model_prob.masked_fill_((target == self.ignore_index).unsqueeze(1), 0)
|
|
|
|
return F.kl_div(output, model_prob, reduction='none').view(batch_size, num_pos, -1).sum(2)
|
|
|
|
|
|
class LayoutlmSPLMPredictionHead(nn.Module):
|
|
def __init__(self, config, src_len):
|
|
super(LayoutlmSPLMPredictionHead, self).__init__()
|
|
self.transform = BertPredictionHeadTransform(config)
|
|
|
|
self.bias = nn.Parameter(torch.zeros(src_len))
|
|
|
|
def forward(self, hidden_states, src_emb):
|
|
hidden_states = self.transform(hidden_states)
|
|
hidden_states = torch.einsum('btf,bsf->bts', hidden_states, src_emb) + self.bias
|
|
# hidden_states = F.linear(hidden_states, weight=src_emb, bias=self.bias)
|
|
return hidden_states
|
|
|
|
|
|
class LayoutlmSPOnlyMLMHead(nn.Module):
|
|
def __init__(self, config, src_len):
|
|
super(LayoutlmSPOnlyMLMHead, self).__init__()
|
|
self.predictions = LayoutlmSPLMPredictionHead(config, src_len=src_len)
|
|
|
|
def forward(self, sequence_output, src_emb):
|
|
prediction_scores = self.predictions(sequence_output, src_emb=src_emb)
|
|
return prediction_scores
|
|
|
|
|
|
class LayoutlmForSequenceToSequence(BertPreTrainedForSeq2SeqModel):
|
|
def __init__(self, config):
|
|
super(LayoutlmForSequenceToSequence, self).__init__(config)
|
|
if config.base_model_type == 'layoutlm':
|
|
self.bert = LayoutlmModel(config)
|
|
else:
|
|
self.bert = BertModel(config)
|
|
self.cls = LayoutlmSPOnlyMLMHead(config, src_len=config.max_source_length)
|
|
self.init_weights()
|
|
|
|
self.log_softmax = nn.LogSoftmax()
|
|
|
|
# setattr(config, 'label_smoothing', 0.1)
|
|
self.source_type_id = config.source_type_id
|
|
self.target_type_id = config.target_type_id
|
|
|
|
if config.label_smoothing > 0:
|
|
self.crit_mask_lm_smoothed = LabelSmoothingLoss(
|
|
config.label_smoothing, config.max_source_length, ignore_index=0, reduction='none')
|
|
self.crit_mask_lm = None
|
|
else:
|
|
self.crit_mask_lm_smoothed = None
|
|
self.crit_mask_lm = nn.CrossEntropyLoss(reduction='none', ignore_index=0)
|
|
|
|
@staticmethod
|
|
def create_mask_and_position_ids(num_tokens, max_len, offset=None):
|
|
base_position_matrix = torch.arange(
|
|
0, max_len, dtype=num_tokens.dtype, device=num_tokens.device).view(1, -1)
|
|
mask = (base_position_matrix < num_tokens.view(-1, 1)).type_as(num_tokens)
|
|
if offset is not None:
|
|
base_position_matrix = base_position_matrix + offset.view(-1, 1)
|
|
position_ids = base_position_matrix * mask
|
|
return mask, position_ids
|
|
|
|
@staticmethod
|
|
def create_attention_mask(source_mask, target_mask, source_position_ids, target_span_ids):
|
|
weight = torch.cat((torch.zeros_like(source_position_ids), target_span_ids, -target_span_ids), dim=1)
|
|
from_weight = weight.unsqueeze(-1)
|
|
to_weight = weight.unsqueeze(1)
|
|
|
|
true_tokens = (0 <= to_weight) & (torch.cat((source_mask, target_mask, target_mask), dim=1) == 1).unsqueeze(1)
|
|
true_tokens_mask = (from_weight >= 0) & true_tokens & (to_weight <= from_weight)
|
|
pseudo_tokens_mask = (from_weight < 0) & true_tokens & (-to_weight > from_weight)
|
|
pseudo_tokens_mask = pseudo_tokens_mask | ((from_weight < 0) & (to_weight == from_weight))
|
|
|
|
return (true_tokens_mask | pseudo_tokens_mask).type_as(source_mask)
|
|
|
|
def forward(self, source_idxys, target_idxys, target_index, pseudo_idxys, num_source_tokens, num_target_tokens,
|
|
target_span_ids=None):
|
|
source_len = source_idxys.size(1)
|
|
target_len = target_idxys.size(1)
|
|
pseudo_len = pseudo_idxys.size(1)
|
|
assert target_len == pseudo_len
|
|
assert source_len > 0 and target_len > 0
|
|
split_lengths = (source_len, target_len, pseudo_len)
|
|
|
|
if self.config.base_model_type == 'layoutlm':
|
|
source_xys = source_idxys[:, :, 1:]
|
|
target_xys = target_idxys[:, :, 1:]
|
|
pseudo_xys = pseudo_idxys[:, :, 1:]
|
|
input_xys = torch.cat((source_xys, target_xys, pseudo_xys), dim=1)
|
|
|
|
source_ids = source_idxys[:, :, 0]
|
|
target_ids = target_idxys[:, :, 0]
|
|
pseudo_ids = pseudo_idxys[:, :, 0]
|
|
else:
|
|
source_ids = source_idxys
|
|
target_ids = target_idxys
|
|
pseudo_ids = pseudo_idxys
|
|
input_xys = None
|
|
|
|
input_ids = torch.cat((source_ids, target_ids, pseudo_ids), dim=1)
|
|
|
|
token_type_ids = torch.cat(
|
|
(torch.ones_like(source_ids) * self.source_type_id,
|
|
torch.ones_like(target_ids) * self.target_type_id,
|
|
torch.ones_like(pseudo_ids) * self.target_type_id), dim=1)
|
|
|
|
source_mask, source_position_ids = \
|
|
self.create_mask_and_position_ids(num_source_tokens, source_len)
|
|
target_mask, target_position_ids = \
|
|
self.create_mask_and_position_ids(num_target_tokens, target_len, offset=num_source_tokens)
|
|
|
|
position_ids = torch.cat((source_position_ids, target_position_ids, target_position_ids), dim=1)
|
|
if target_span_ids is None:
|
|
target_span_ids = target_position_ids
|
|
attention_mask = self.create_attention_mask(source_mask, target_mask, source_position_ids, target_span_ids)
|
|
|
|
if self.config.base_model_type == 'layoutlm':
|
|
outputs = self.bert(
|
|
input_ids, input_xys, attention_mask=attention_mask, token_type_ids=token_type_ids,
|
|
position_ids=position_ids, split_lengths=split_lengths, return_emb=True)
|
|
else:
|
|
outputs = self.bert(
|
|
input_ids, attention_mask=attention_mask, token_type_ids=token_type_ids,
|
|
position_ids=position_ids, split_lengths=split_lengths, return_emb=True)
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sequence_output = outputs[0]
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pseudo_sequence_output = sequence_output[:, source_len + target_len:, ]
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sequence_embedding = outputs[-1]
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source_embedding = sequence_embedding[:, :source_len, :]
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def loss_mask_and_normalize(loss, mask):
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mask = mask.type_as(loss)
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loss = loss * mask
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denominator = torch.sum(mask) + 1e-5
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return (loss / denominator).sum()
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# TODO: do we need to mask the impossible pos with the real input length
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prediction_scores_masked = self.cls(pseudo_sequence_output, source_embedding)
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if self.crit_mask_lm_smoothed:
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masked_lm_loss = self.crit_mask_lm_smoothed(
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F.log_softmax(prediction_scores_masked.float(), dim=-1), target_index)
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else:
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masked_lm_loss = self.crit_mask_lm(
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prediction_scores_masked.transpose(1, 2).float(), target_index)
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pseudo_lm_loss = loss_mask_and_normalize(
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masked_lm_loss.float(), target_mask)
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|
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return pseudo_lm_loss
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|