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modelscope/modelscope/models/nlp/bert/document_segmentation.py

112 lines
3.8 KiB
Python

# Copyright (c) Alibaba, Inc. and its affiliates.
from typing import Any, Dict
import torch
from torch import nn
from torch.nn import CrossEntropyLoss
from transformers.modeling_outputs import TokenClassifierOutput
from transformers.models.bert.modeling_bert import (BertModel,
BertPreTrainedModel)
from modelscope.metainfo import Models
from modelscope.models.base import Model
from modelscope.models.builder import MODELS
from modelscope.utils.constant import Tasks
__all__ = ['BertForDocumentSegmentation']
@MODELS.register_module(
Tasks.document_segmentation, module_name=Models.bert_for_ds)
class BertForDocumentSegmentation(Model):
def __init__(self, model_dir: str, model_config: Dict[str, Any], *args,
**kwargs):
super().__init__(model_dir, model_config, *args, **kwargs)
self.model_cfg = model_config
def build_with_config(self, config):
self.bert_model = BertForDocumentSegmentationBase.from_pretrained(
self.model_dir, from_tf=False, config=config)
return self.bert_model
def forward(self) -> Dict[str, Any]:
return self.model_cfg
class BertForDocumentSegmentationBase(BertPreTrainedModel):
_keys_to_ignore_on_load_unexpected = [r'pooler']
def __init__(self, config):
super().__init__(config)
self.num_labels = config.num_labels
self.sentence_pooler_type = None
self.bert = BertModel(config, add_pooling_layer=False)
classifier_dropout = config.hidden_dropout_prob
self.dropout = nn.Dropout(classifier_dropout)
self.classifier = nn.Linear(config.hidden_size, config.num_labels)
self.class_weights = None
self.init_weights()
def forward(self,
input_ids=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
head_mask=None,
sentence_attention_mask=None,
inputs_embeds=None,
labels=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None):
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]
if self.sentence_pooler_type is not None:
raise NotImplementedError
else:
sequence_output = self.dropout(sequence_output)
logits = self.classifier(sequence_output)
loss = None
if labels is not None:
loss_fct = CrossEntropyLoss(weight=self.class_weights)
if sentence_attention_mask is not None:
active_loss = sentence_attention_mask.view(-1) == 1
active_logits = logits.view(-1, self.num_labels)
active_labels = torch.where(
active_loss, labels.view(-1),
torch.tensor(loss_fct.ignore_index).type_as(labels))
loss = loss_fct(active_logits, active_labels)
else:
loss = loss_fct(
logits.view(-1, self.num_labels), labels.view(-1))
if not return_dict:
output = (logits, ) + outputs[2:]
return ((loss, ) + output) if loss is not None else output
return TokenClassifierOutput(
loss=loss,
logits=logits,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
)