48 lines
1.5 KiB
Python
48 lines
1.5 KiB
Python
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#!/usr/bin/env python3
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# Copyright (c) 2020 Mobvoi Inc (Binbin Zhang)
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#
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# Licensed under the Apache License, Version 2.0 (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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# http://www.apache.org/licenses/LICENSE-2.0
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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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class GlobalCMVN(torch.nn.Module):
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def __init__(self,
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mean: torch.Tensor,
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istd: torch.Tensor,
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norm_var: bool = True):
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"""
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Args:
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mean (torch.Tensor): mean stats
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istd (torch.Tensor): inverse std, std which is 1.0 / std
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"""
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super().__init__()
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assert mean.shape == istd.shape
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self.norm_var = norm_var
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# The buffer can be accessed from this module using self.mean
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self.register_buffer("mean", mean)
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self.register_buffer("istd", istd)
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def forward(self, x: torch.Tensor):
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"""
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Args:
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x (torch.Tensor): (batch, max_len, feat_dim)
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Returns:
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(torch.Tensor): normalized feature
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"""
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x = x - self.mean
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if self.norm_var:
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x = x * self.istd
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return x
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