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2026-07-13 12:40:42 +08:00

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Python

# Copyright (c) 2023 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.
import paddle
from paddle import _legacy_C_ops
from paddle.framework import in_dynamic_mode
class FusedDropout(paddle.nn.Layer):
r"""
Dropout is a regularization technique for reducing overfitting by preventing
neuron co-adaption during training as described in the paper:
`Improving neural networks by preventing co-adaptation of feature detectors <https://arxiv.org/abs/1207.0580>`_
The dropout operator randomly sets the outputs of some units to zero, while upscale others
according to the given dropout probability.
It is an optimized implementation for ``paddle.nn.Dropout``.
In dygraph mode, please use ``eval()`` to switch to evaluation mode, where dropout is disabled.
Parameters:
p (float|int, optional): Probability of setting units to zero. Default: 0.5
axis (int|list|tuple, optional): The axis along which the dropout is performed. Default: None.
mode(str, optional): ['upscale_in_train'(default) | 'downscale_in_infer']
1. upscale_in_train (default), upscale the output at training time
- train: :math:`out = input \times \frac{mask}{(1.0 - p)}`
- inference: :math:`out = input`
2. downscale_in_infer, downscale the output at inference
- train: :math:`out = input \times mask`
- inference: :math:`out = input \times (1.0 - p)`
name (str, optional): Name for the operation, Default: None. For more information, please refer to :ref:`api_guide_Name`.
Shape:
- input: N-D tensor.
- output: N-D tensor, the same shape as input.
Examples:
.. code-block:: pycon
>>> import paddle
>>> paddle.seed(2023)
>>> x = paddle.to_tensor([[1, 2, 3], [4, 5, 6]], dtype="float32")
>>> m = paddle.incubate.nn.FusedDropout(p=0.5)
>>> y_train = m(x)
>>> print(y_train)
Tensor(shape=[2, 3], dtype=float32, place=Place(cpu), stop_gradient=True,
[[0., 0., 6.],
[0., 0., 0.]])
>>> m.eval() # switch the model to test phase
>>> y_test = m(x)
>>> print(y_test)
Tensor(shape=[2, 3], dtype=float32, place=Place(cpu), stop_gradient=True,
[[1., 2., 3.],
[4., 5., 6.]])
"""
def __init__(self, p=0.5, axis=None, mode="upscale_in_train", name=None):
super().__init__()
if not isinstance(p, (float, int)):
raise TypeError("p argument should be a number")
if p < 0 or p > 1:
raise ValueError("p argument should between 0 and 1")
mode = (
'downgrade_in_infer' if mode == 'downscale_in_infer' else mode
) # semantic transfer
if mode not in ('downscale_in_infer', 'upscale_in_train'):
raise ValueError(
"mode argument should be 'downscale_in_infer' or 'upscale_in_train'"
)
if axis and not isinstance(axis, (int, list, tuple)):
raise TypeError("datatype of axis argument should be int or list")
self.p = p
self.mode = mode
self.name = name
self.axis = None
if axis is not None:
self.axis = [axis] if isinstance(axis, int) else list(axis)
def forward(self, input):
# fast return for p == 0
if self.p == 0:
return input
if self.axis is not None and in_dynamic_mode():
seed = None
if paddle.static.default_main_program().random_seed != 0:
seed = paddle.static.default_main_program().random_seed
out, mask = _legacy_C_ops.dropout_nd(
input,
'dropout_prob',
self.p,
'is_test',
not self.training,
'fix_seed',
seed is not None,
'seed',
seed if seed is not None else 0,
'dropout_implementation',
self.mode,
'axis',
self.axis,
)
else:
out = paddle.nn.functional.dropout(
input,
p=self.p,
axis=self.axis,
training=self.training,
mode=self.mode,
name=self.name,
)
return out
def extra_repr(self):
name_str = f', name={self.name}' if self.name else ''
return f'p={self.p}, axis={self.axis}, mode={self.mode}{name_str}'