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Paddle/python/paddle/nn/initializer/kaiming.py

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3.3 KiB

# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
#
# 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.
# TODO: define the initializers of Kaiming functions in neural network
from ...fluid.initializer import MSRAInitializer
__all__ = ['KaimingUniform', 'KaimingNormal']
class KaimingNormal(MSRAInitializer):
"""Implements the Kaiming Normal initializer
This class implements the weight initialization from the paper
`Delving Deep into Rectifiers: Surpassing Human-Level Performance on
ImageNet Classification <https://arxiv.org/abs/1502.01852>`_
by Kaiming He, Xiangyu Zhang, Shaoqing Ren and Jian Sun. This is a
robust initialization method that particularly considers the rectifier
nonlinearities.
In case of Normal distribution, the mean is 0 and the standard deviation
is
.. math::
\sqrt{\\frac{2.0}{fan\_in}}
Args:
fan_in (float32|None): fan_in for Kaiming normal Initializer. If None, it is\
inferred from the variable. default is None.
Note:
It is recommended to set fan_in to None for most cases.
Examples:
.. code-block:: python
import paddle
import paddle.nn as nn
linear = nn.Linear(2,
4,
weight_attr=nn.initializer.KaimingNormal())
data = paddle.rand([30, 10, 2], dtype='float32')
res = linear(data)
"""
def __init__(self, fan_in=None):
super(KaimingNormal, self).__init__(
uniform=False, fan_in=fan_in, seed=0)
class KaimingUniform(MSRAInitializer):
"""Implements the Kaiming Uniform initializer
This class implements the weight initialization from the paper
`Delving Deep into Rectifiers: Surpassing Human-Level Performance on
ImageNet Classification <https://arxiv.org/abs/1502.01852>`_
by Kaiming He, Xiangyu Zhang, Shaoqing Ren and Jian Sun. This is a
robust initialization method that particularly considers the rectifier
nonlinearities.
In case of Uniform distribution, the range is [-x, x], where
.. math::
x = \sqrt{\\frac{6.0}{fan\_in}}
Args:
fan_in (float32|None): fan_in for Kaiming uniform Initializer. If None, it is\
inferred from the variable. default is None.
Note:
It is recommended to set fan_in to None for most cases.
Examples:
.. code-block:: python
import paddle
import paddle.nn as nn
linear = nn.Linear(2,
4,
weight_attr=nn.initializer.KaimingUniform())
data = paddle.rand([30, 10, 2], dtype='float32')
res = linear(data)
"""
def __init__(self, fan_in=None):
super(KaimingUniform, self).__init__(
uniform=True, fan_in=fan_in, seed=0)