41 lines
1.3 KiB
Python
41 lines
1.3 KiB
Python
# Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved.
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#
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# Licensed under the BSD 3-Clause License (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://opensource.org/licenses/BSD-3-Clause
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import torch
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import torch.nn as nn
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class LabelSmoothing(nn.Module):
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"""
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NLL loss with label smoothing.
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"""
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def __init__(self, smoothing=0.0):
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"""
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Constructor for the LabelSmoothing module.
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:param smoothing: label smoothing factor
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"""
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super(LabelSmoothing, self).__init__()
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self.confidence = 1.0 - smoothing
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self.smoothing = smoothing
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def forward(self, x, target):
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logprobs = torch.nn.functional.log_softmax(x, dim=-1)
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nll_loss = -logprobs.gather(dim=-1, index=target.unsqueeze(1))
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nll_loss = nll_loss.squeeze(1)
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smooth_loss = -logprobs.mean(dim=-1)
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loss = self.confidence * nll_loss + self.smoothing * smooth_loss
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return loss.mean()
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