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from transformers import BertModel | |
import torch | |
import onnx | |
import pytorch_lightning as pl | |
import wandb | |
from metrics import MyAccuracy | |
from utils import num_unique_labels | |
from typing import Dict, Tuple, List, Optional | |
class MultiTaskBertModel(pl.LightningModule): | |
""" | |
Multi-task Bert model for Named Entity Recognition (NER) and Intent Classification | |
Args: | |
config (BertConfig): Bert model configuration. | |
dataset (Dict[str, Union[str, List[str]]]): A dictionary containing keys 'text', 'ner', and 'intent'. | |
""" | |
def __init__(self, config, dataset): | |
super().__init__() | |
self.num_ner_labels, self.num_intent_labels = num_unique_labels(dataset) | |
self.dropout = torch.nn.Dropout(config.hidden_dropout_prob) | |
self.model = BertModel(config=config) | |
self.ner_classifier = torch.nn.Linear(config.hidden_size, self.num_ner_labels) | |
self.intent_classifier = torch.nn.Linear(config.hidden_size, self.num_intent_labels) | |
# log hyperparameters | |
self.save_hyperparameters() | |
self.accuracy = MyAccuracy() | |
def forward(self, input_ids: torch.Tensor, attention_mask: Optional[torch.Tensor] = None) -> Tuple[torch.Tensor, torch.Tensor]: | |
""" | |
Perform a forward pass through Multi-task Bert model. | |
Args: | |
input_ids (torch.Tensor, torch.shape: (batch, length_of_tokenized_sequences)): Input token IDs. | |
attention_mask (Optional[torch.Tensor]): Attention mask for input tokens. | |
Returns: | |
Tuple[torch.Tensor,torch.Tensor]: NER logits, Intent logits. | |
""" | |
outputs = self.model(input_ids=input_ids, attention_mask=attention_mask) | |
sequence_output = outputs[0] | |
sequence_output = self.dropout(sequence_output) | |
ner_logits = self.ner_classifier(sequence_output) | |
pooled_output = outputs[1] | |
pooled_output = self.dropout(pooled_output) | |
intent_logits = self.intent_classifier(pooled_output) | |
return ner_logits, intent_logits | |
def training_step(self: pl.LightningModule, batch, batch_idx: int) -> torch.Tensor: | |
""" | |
Perform a training step for the Multi-task BERT model. | |
Args: | |
batch: Input batch. | |
batch_idx (int): Index of the batch. | |
Returns: | |
torch.Tensor: Loss value | |
""" | |
loss, ner_logits, intent_logits, ner_labels, intent_labels = self._common_step(batch, batch_idx) | |
accuracy_ner = self.accuracy(ner_logits, ner_labels, self.num_ner_labels) | |
accuracy_intent = self.accuracy(intent_logits, intent_labels, self.num_intent_labels) | |
self.log_dict({'training_loss': loss, 'ner_accuracy': accuracy_ner, 'intent_accuracy': accuracy_intent}, | |
on_step=False, on_epoch=True, prog_bar=True) | |
return loss | |
def on_validation_epoch_start(self): | |
self.validation_step_outputs_ner = [] | |
self.validation_step_outputs_intent = [] | |
def validation_step(self, batch, batch_idx: int) -> torch.Tensor: | |
""" | |
Perform a validation step for the Multi-task BERT model. | |
Args: | |
batch: Input batch. | |
batch_idx (int): Index of the batch. | |
Returns: | |
torch.Tensor: Loss value. | |
""" | |
loss, ner_logits, intent_logits, ner_labels, intent_labels = self._common_step(batch, batch_idx) | |
# self.log('val_loss', loss) | |
accuracy_ner = self.accuracy(ner_logits, ner_labels, self.num_ner_labels) | |
accuracy_intent = self.accuracy(intent_logits, intent_labels, self.num_intent_labels) | |
self.log_dict({'validation_loss': loss, 'val_ner_accuracy': accuracy_ner, 'val_intent_accuracy': accuracy_intent}, | |
on_step=False, on_epoch=True, prog_bar=True) | |
self.validation_step_outputs_ner.append(ner_logits) | |
self.validation_step_outputs_intent.append(intent_logits) | |
return loss | |
def on_validation_epoch_end(self): | |
""" | |
Perform actions at the end of validation epoch to track the training process in WandB. | |
""" | |
validation_step_outputs_ner = self.validation_step_outputs_ner | |
validation_step_outputs_intent = self.validation_step_outputs_intent | |
dummy_input = torch.zeros((1, 128), device=self.device, dtype=torch.long) | |
model_filename = f"model_{str(self.global_step).zfill(5)}.onnx" | |
torch.onnx.export(self, dummy_input, model_filename) | |
artifact = wandb.Artifact(name="model.ckpt", type="model") | |
artifact.add_file(model_filename) | |
self.logger.experiment.log_artifact(artifact) | |
flattened_logits_ner = torch.flatten(torch.cat(validation_step_outputs_ner)) | |
flattened_logits_intent = torch.flatten(torch.cat(validation_step_outputs_intent)) | |
self.logger.experiment.log( | |
{"valid/ner_logits": wandb.Histogram(flattened_logits_ner.to('cpu')), | |
"valid/intent_logits": wandb.Histogram(flattened_logits_intent.to('cpu')), | |
"global_step": self.global_step} | |
) | |
def _common_step(self, batch, batch_idx): | |
""" | |
Common steps for both training and validation. Calculate loss for both NER and intent layer. | |
Returns: | |
Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]: | |
Combiner loss value, NER logits, intent logits, NER labels, intent labels. | |
""" | |
ids = batch['input_ids'] | |
mask = batch['attention_mask'] | |
ner_labels = batch['ner_labels'] | |
intent_labels = batch['intent_labels'] | |
ner_logits, intent_logits = self.forward(input_ids=ids, attention_mask=mask) | |
criterion = torch.nn.CrossEntropyLoss() | |
ner_loss = criterion(ner_logits.view(-1, self.num_ner_labels), ner_labels.view(-1).long()) | |
intent_loss = criterion(intent_logits.view(-1, self.num_intent_labels), intent_labels.view(-1).long()) | |
loss = ner_loss + intent_loss | |
return loss, ner_logits, intent_logits, ner_labels, intent_labels | |
def configure_optimizers(self): | |
optimizer = torch.optim.Adam(self.parameters(), lr=1e-5) | |
return optimizer |