未验证 提交 988fbf82 编写于 作者: G Guanghua Yu 提交者: GitHub

Fix bug with wrong calculation result in `nn.loss.CrossEntropyLoss` (#24352)

* fix bug of cross_entropy_loss,test=develop
* fix log_softmax and some comment,test=develop
上级 8d0bae2d
......@@ -14,6 +14,7 @@
# TODO: define loss functions of neural network
import paddle.fluid as fluid
import paddle
__all__ = [
# 'NCELoss',
......@@ -27,8 +28,8 @@ __all__ = [
class CrossEntropyLoss(fluid.dygraph.Layer):
"""
This operator implements the cross entropy loss function. This OP combines ``softmax``,
``cross_entropy``, and ``reduce_sum``/``reduce_mean`` together.
This operator implements the cross entropy loss function. This OP combines ``LogSoftmax``,
and ``NLLLoss`` together.
It is useful when training a classification problem with ``C`` classes.
If provided, the optional argument ``weight`` should be a 1D Variable assigning
......@@ -49,19 +50,23 @@ class CrossEntropyLoss(fluid.dygraph.Layer):
\\log\\left(\\sum_{i=0}^{K}\\exp(\\text{input}_i)\\right)), j = 1,..., K
Parameters:
input (Variable): Input tensor, the data type is float32,
float64, int32, int64.
label (Variable): Label tensor, the data type is float32,
float64, int32, int64.
input (Variable): Input tensor, the data type is float32, float64. Shape is
(N, C), where C is number of classes, and if shape is more than 2D, this
is (N, C, D1, D2,..., Dk), k >= 1.
label (Variable): Label tensor, the data type is int64. Shape is (N), where each
value is 0 <= label[i] <= C-1, and if shape is more than 2D, this is
(N, D1, D2,..., Dk), k >= 1.
weight (Variable, optional): Weight tensor, a manual rescaling weight given
to each class. It has the same dimensions as class number and the data type
is float32, float64, int32, int64. Default is ``'None'``.
to each class and the shape is (C). It has the same dimensions as class
number and the data type is float32, float64. Default is ``'None'``.
reduction (str, optional): Indicate how to average the loss by batch_size,
the candicates are ``'none'`` | ``'mean'`` | ``'sum'``.
If :attr:`reduction` is ``'mean'``, the reduced mean loss is returned;
If :attr:`size_average` is ``'sum'``, the reduced sum loss is returned.
If :attr:`reduction` is ``'none'``, the unreduced loss is returned.
Default is ``'mean'``.
ignore_index (int64, optional): Specifies a target value that is ignored
and does not contribute to the input gradient. Default is ``-100``.
Returns:
The tensor variable storing the cross_entropy_loss of input and label.
......@@ -76,17 +81,17 @@ class CrossEntropyLoss(fluid.dygraph.Layer):
import paddle.fluid as fluid
import numpy as np
input = fluid.layers.data(name='input', shape=[5, 100], dtype='float32')
label = fluid.layers.data(name='label', shape=[5, 1], dtype='int64')
weight = fluid.layers.data(name='weight', shape=[100], dtype='float32')
input = fluid.data(name='input', shape=[5, 100], dtype='float64')
label = fluid.data(name='label', shape=[5], dtype='int64')
weight = fluid.data(name='weight', shape=[100], dtype='float64')
ce_loss = paddle.nn.loss.CrossEntropyLoss(weight=weight, reduction='mean')
output = ce_loss(input,label)
output = ce_loss(input, label)
place = fluid.CPUPlace()
exe = fluid.Executor(place)
exe.run(fluid.default_startup_program())
input_data = np.random.random([5, 100]).astype("float32")
label_data = np.array([[1], [9], [40], [50], [90]]).astype("int64")
weight_data = np.random.random([100]).astype("float32")
input_data = np.random.random([5, 100]).astype("float64")
label_data = np.random.randint(0, 100, size=(5)).astype(np.int64)
weight_data = np.random.random([100]).astype("float64")
output = exe.run(fluid.default_main_program(),
feed={"input": input_data, "label": label_data,"weight": weight_data},
fetch_list=[output],
......@@ -104,41 +109,36 @@ class CrossEntropyLoss(fluid.dygraph.Layer):
print(output.numpy())
"""
def __init__(self, weight=None, reduction='mean'):
def __init__(self, weight=None, reduction='mean', ignore_index=-100):
super(CrossEntropyLoss, self).__init__()
self.weight = weight
self.reduction = reduction
self.ignore_index = ignore_index
def forward(self, input, label):
fluid.data_feeder.check_variable_and_dtype(
input, 'input', ['float32', 'float64', 'int32', 'int64'],
'cross_entropy_loss')
fluid.data_feeder.check_variable_and_dtype(
label, 'label', ['float32', 'float64', 'int32', 'int64'],
input, 'input', ['float32', 'float64'], 'cross_entropy_loss')
fluid.data_feeder.check_variable_and_dtype(label, 'label', ['int64'],
'cross_entropy_loss')
if self.reduction not in ['sum', 'mean', 'none']:
raise ValueError(
"The value of 'reduction' in cross_entropy_loss should be 'sum', 'mean' or 'none',"
" but received %s, which is not allowed." % self.reduction)
softmax_out = fluid.layers.softmax(input)
if self.weight is not None:
if isinstance(self.weight, fluid.framework.Variable):
softmax_out = fluid.layers.elementwise_pow(
softmax_out, self.weight, axis=-1)
else:
"The value of 'reduction' in cross_entropy_loss should be 'sum', 'mean' or"
" 'none', but received %s, which is not allowed." %
self.reduction)
log_softmax = paddle.nn.LogSoftmax()
log_softmax_out = log_softmax(input)
if self.weight is not None and not isinstance(self.weight,
fluid.framework.Variable):
raise ValueError(
"The weight' is not a Variable, please convert to Variable.")
nll_loss = paddle.nn.loss.NLLLoss(
weight=self.weight,
reduction=self.reduction,
ignore_index=self.ignore_index)
out = fluid.layers.cross_entropy(softmax_out, label)
if self.reduction == 'sum':
return fluid.layers.reduce_sum(out)
elif self.reduction == 'mean':
return fluid.layers.reduce_mean(out)
else:
return out
return nll_loss(log_softmax_out, label)
class MSELoss(fluid.dygraph.layers.Layer):
......@@ -578,7 +578,6 @@ class NLLLoss(fluid.dygraph.Layer):
inputs = {'X': input, 'Label': label}
attrs = {'reduction': self.reduction, 'ignore_index': self.ignore_index}
if self.weight is not None:
if isinstance(self.weight, fluid.framework.Variable):
inputs['Weight'] = self.weight
......
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