比较与torch.nn.NLLLoss的差异
torch.nn.NLLLoss
torch.nn.NLLLoss(
weight=None,
size_average=None,
ignore_index=-100,
reduce=None,
reduction='mean'
)(input, target)
更多内容详见torch.nn.NLLLoss。
mindspore.nn.NLLLoss
class mindspore.nn.NLLLoss(
weight=None,
ignore_index=-100,
reduction='mean'
)(logits, labels)
更多内容详见mindspore.nn.NLLLoss。
差异对比
PyTorch:计算预测值和目标值之间的负对数似然损失。
MindSpore:除两个在PyTorch已弃用的参数不同外,功能上无差异。
分类 |
子类 |
PyTorch |
MindSpore |
差异 |
---|---|---|---|---|
参数 |
参数1 |
weight |
weight |
指定各类别的权重 |
参数2 |
size_average |
- |
已弃用,被reduction取代,MindSpore无此参数 |
|
参数3 |
ignore_index |
ignore_index |
指定labels中需要忽略的值(一般为填充值),使其不对梯度产生影响 |
|
参数4 |
reduce |
- |
已弃用,被reduction取代,MindSpore无此参数 |
|
参数5 |
reduction |
reduction |
指定应用于输出结果的计算方式 |
|
输入 |
输入1 |
input |
logits |
功能一致,参数名不同 |
输入2 |
target |
labels |
功能一致,参数名不同 |
代码示例
import numpy as np
data = np.random.randn(2, 2, 3, 3)
# In MindSpore
import mindspore as ms
loss = ms.nn.NLLLoss(ignore_index=-110, reduction="none")
input = ms.Tensor(data, dtype=ms.float32)
target = ms.ops.zeros((2, 3, 3), dtype=ms.int32)
output = loss(input, target)
print(output)
# Out:
# [[[ 0.7047795 0.8196785 -0.7913506 ]
# [ 0.22157642 -0.18818447 -0.65975004]
# [ 1.7223285 -0.9269855 0.46461168]]
#
# [[ 0.21305805 -2.213903 0.36110482]
# [-0.1900587 -0.56938815 0.12274747]
# [ 1.149195 -0.8739661 -1.7944012 ]]]
# In PyTorch
import torch
loss = torch.nn.NLLLoss(ignore_index=-110, reduction="none")
input = torch.tensor(data, dtype=torch.float32)
target = torch.zeros((2, 3, 3), dtype=torch.long)
output = loss(input, target)
print(output)
# Out:
# tensor([[[ 0.7048, 0.8197, -0.7914],
# [ 0.2216, -0.1882, -0.6598],
# [ 1.7223, -0.9270, 0.4646]],
# [[ 0.2131, -2.2139, 0.3611],
# [-0.1901, -0.5694, 0.1227],
# [ 1.1492, -0.8740, -1.7944]]])