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Paddle/python/paddle/incubate/hapi/loss.py

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4.4 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.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import os
from paddle import fluid
from paddle.fluid.framework import in_dygraph_mode, Variable
from paddle.fluid.dygraph.base import to_variable
from .utils import to_list
__all__ = ['Loss', 'CrossEntropy', 'SoftmaxWithCrossEntropy']
class Loss(object):
"""
Base class for loss, encapsulates loss logic and APIs
Usage:
custom_loss = CustomLoss()
loss = custom_loss(inputs, labels)
Examples:
.. code-block:: python
from paddle.incubate.hapi.loss import Loss
from paddle import fluid
class SoftmaxWithCrossEntropy(Loss):
def __init__(self, average=True):
super(SoftmaxWithCrossEntropy, self).__init__(average)
def forward(self, outputs, labels):
return [
fluid.layers.softmax_with_cross_entropy(
o, l, return_softmax=False) for o, l in zip(outputs, labels)
]
"""
def __init__(self, average=True):
super(Loss, self).__init__()
self.average = average
def forward(self, outputs, labels):
raise NotImplementedError()
def __call__(self, outputs, labels=None):
labels = to_list(labels)
if in_dygraph_mode() and labels:
labels = [to_variable(l) for l in labels]
losses = to_list(self.forward(to_list(outputs), labels))
if self.average:
losses = [fluid.layers.reduce_mean(l) for l in losses]
else:
losses = [fluid.layers.reduce_sum(l) for l in losses]
return losses
class CrossEntropy(Loss):
"""
Args:
input (list[Variable]): Input tensor, the data type is float32,
float64, int32, int64.
label (list[Variable]): Label tensor, the data type is float32,
float64, int32, int64.
average (bool, optional): Indicate whether to average the loss, Default: True.
Returns:
list[Variable]: The tensor variable storing the cross_entropy_loss of inputs and labels.
Examples:
.. code-block:: python
import paddle.fluid as fluid
import paddle.incubate.hapi as hapi
fluid.enable_dygraph()
model = hapi.Model(hapi.vision.LeNet())
model.prepare(loss_function=hapi.loss.CrossEntropy())
"""
def __init__(self, average=True):
super(CrossEntropy, self).__init__(average)
def forward(self, outputs, labels):
return [
fluid.layers.cross_entropy(o, l) for o, l in zip(outputs, labels)
]
class SoftmaxWithCrossEntropy(Loss):
"""
this op combined softmax and cross entropy.
Args:
input (list[Variable]): Input tensor, the data type is float32,
float64, int32, int64.
label (list[Variable]): Label tensor, the data type is float32,
float64, int32, int64.
average (bool, optional): Indicate whether to average the loss, Default: True.
Returns:
list[Variable]: The tensor variable storing the cross_entropy_loss of inputs and labels.
Examples:
.. code-block:: python
import paddle.fluid as fluid
import paddle.incubate.hapi as hapi
fluid.enable_dygraph()
model = hapi.Model(hapi.vision.LeNet(classifier_activation=None))
loss = hapi.loss.SoftmaxWithCrossEntropy()
model.prepare(loss_function=loss)
"""
def __init__(self, average=True):
super(SoftmaxWithCrossEntropy, self).__init__(average)
def forward(self, outputs, labels):
return [
fluid.layers.softmax_with_cross_entropy(
o, l, return_softmax=False) for o, l in zip(outputs, labels)
]