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#imported from https://github.com/m3hrdadfi/soxan to implement Wav2Vec2 for speech classification
import torch
import torch.nn as nn
from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss
from transformers.models.wav2vec2.modeling_wav2vec2 import (
Wav2Vec2PreTrainedModel,
Wav2Vec2Model
)
from src.modeling_outputs import SpeechClassifierOutput
class Wav2Vec2ClassificationHead(nn.Module):
"""Head for wav2vec classification task."""
def __init__(self, config):
super().__init__()
self.dense = nn.Linear(config.hidden_size, config.hidden_size)
self.dropout = nn.Dropout(config.final_dropout)
self.out_proj = nn.Linear(config.hidden_size, config.num_labels)
def forward(self, features, **kwargs):
x = features
x = self.dropout(x)
x = self.dense(x)
x = torch.tanh(x)
x = self.dropout(x)
x = self.out_proj(x)
return x
class Wav2Vec2ForSpeechClassification(Wav2Vec2PreTrainedModel):
def __init__(self, config):
super().__init__(config)
self.num_labels = config.num_labels
self.pooling_mode = config.pooling_mode
self.config = config
self.wav2vec2 = Wav2Vec2Model(config)
self.classifier = Wav2Vec2ClassificationHead(config)
self.init_weights()
def freeze_feature_extractor(self):
self.wav2vec2.feature_extractor._freeze_parameters()
def merged_strategy(
self,
hidden_states,
mode="mean"
):
if mode == "mean":
outputs = torch.mean(hidden_states, dim=1)
elif mode == "sum":
outputs = torch.sum(hidden_states, dim=1)
elif mode == "max":
outputs = torch.max(hidden_states, dim=1)[0]
else:
raise Exception(
"The pooling method hasn't been defined! Your pooling mode must be one of these ['mean', 'sum', 'max']")
return outputs
def forward(
self,
input_values,
attention_mask=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
labels=None,
):
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
outputs = self.wav2vec2(
input_values,
attention_mask=attention_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
hidden_states = outputs[0]
hidden_states = self.merged_strategy(hidden_states, mode=self.pooling_mode)
logits = self.classifier(hidden_states)
loss = None
if labels is not None:
if self.config.problem_type is None:
if self.num_labels == 1:
self.config.problem_type = "regression"
elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int):
self.config.problem_type = "single_label_classification"
else:
self.config.problem_type = "multi_label_classification"
if self.config.problem_type == "regression":
loss_fct = MSELoss()
loss = loss_fct(logits.view(-1, self.num_labels), labels)
elif self.config.problem_type == "single_label_classification":
loss_fct = CrossEntropyLoss()
loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
elif self.config.problem_type == "multi_label_classification":
loss_fct = BCEWithLogitsLoss()
loss = loss_fct(logits, labels)
if not return_dict:
output = (logits,) + outputs[2:]
return ((loss,) + output) if loss is not None else output
return SpeechClassifierOutput(
loss=loss,
logits=logits,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
)