diff --git a/egs/speech_llm/ASR_LLM/whisper_llm_zh/label_smoothing.py b/egs/speech_llm/ASR_LLM/whisper_llm_zh/label_smoothing.py new file mode 100644 index 000000000..52d2eda3b --- /dev/null +++ b/egs/speech_llm/ASR_LLM/whisper_llm_zh/label_smoothing.py @@ -0,0 +1,109 @@ +# Copyright 2021 Xiaomi Corp. (authors: Fangjun Kuang) +# +# See ../../../../LICENSE for clarification regarding multiple authors +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +import torch + + +class LabelSmoothingLoss(torch.nn.Module): + """ + Implement the LabelSmoothingLoss proposed in the following paper + https://arxiv.org/pdf/1512.00567.pdf + (Rethinking the Inception Architecture for Computer Vision) + + """ + + def __init__( + self, + ignore_index: int = -1, + label_smoothing: float = 0.1, + reduction: str = "sum", + ) -> None: + """ + Args: + ignore_index: + ignored class id + label_smoothing: + smoothing rate (0.0 means the conventional cross entropy loss) + reduction: + It has the same meaning as the reduction in + `torch.nn.CrossEntropyLoss`. It can be one of the following three + values: (1) "none": No reduction will be applied. (2) "mean": the + mean of the output is taken. (3) "sum": the output will be summed. + """ + super().__init__() + assert 0.0 <= label_smoothing < 1.0, f"{label_smoothing}" + assert reduction in ("none", "sum", "mean"), reduction + self.ignore_index = ignore_index + self.label_smoothing = label_smoothing + self.reduction = reduction + + def forward(self, x: torch.Tensor, target: torch.Tensor) -> torch.Tensor: + """ + Compute loss between x and target. + + Args: + x: + prediction of dimension + (batch_size, input_length, number_of_classes). + target: + target masked with self.ignore_index of + dimension (batch_size, input_length). + + Returns: + A scalar tensor containing the loss without normalization. + """ + assert x.ndim == 3 + assert target.ndim == 2 + assert x.shape[:2] == target.shape + num_classes = x.size(-1) + x = x.reshape(-1, num_classes) + # Now x is of shape (N*T, C) + + # We don't want to change target in-place below, + # so we make a copy of it here + target = target.clone().reshape(-1) + + ignored = target == self.ignore_index + + # See https://github.com/k2-fsa/icefall/issues/240 + # and https://github.com/k2-fsa/icefall/issues/297 + # for why we don't use target[ignored] = 0 here + target = torch.where(ignored, torch.zeros_like(target), target) + + true_dist = torch.nn.functional.one_hot(target, num_classes=num_classes).to(x) + + true_dist = ( + true_dist * (1 - self.label_smoothing) + self.label_smoothing / num_classes + ) + + # Set the value of ignored indexes to 0 + # + # See https://github.com/k2-fsa/icefall/issues/240 + # and https://github.com/k2-fsa/icefall/issues/297 + # for why we don't use true_dist[ignored] = 0 here + true_dist = torch.where( + ignored.unsqueeze(1).repeat(1, true_dist.shape[1]), + torch.zeros_like(true_dist), + true_dist, + ) + + loss = -1 * (torch.log_softmax(x, dim=1) * true_dist) + if self.reduction == "sum": + return loss.sum() + elif self.reduction == "mean": + return loss.sum() / (~ignored).sum() + else: + return loss.sum(dim=-1)