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52 lines
1.6 KiB
52 lines
1.6 KiB
# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
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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 paddle
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from paddle import nn
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from deepspeech.utils.log import Log
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logger = Log(__name__).getlog()
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__all__ = ['GlobalCMVN']
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class GlobalCMVN(nn.Layer):
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def __init__(self,
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mean: paddle.Tensor,
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istd: paddle.Tensor,
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norm_var: bool=True):
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"""
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Args:
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mean (paddle.Tensor): mean stats
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istd (paddle.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: paddle.Tensor):
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"""
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Args:
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x (paddle.Tensor): (batch, max_len, feat_dim)
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Returns:
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(paddle.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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