gfocalloss损失函数代码
时间: 2023-12-25 12:25:24 浏览: 38
GFocalLoss损失函数代码如下:
```python
import torch
import torch.nn as nn
import torch.nn.functional as F
class GFocalLoss(nn.Module):
def __init__(self, beta=2.0,use_sigmoid=True):
super().__init__()
self.beta = beta
self.use_sigmoid = use_sigmoid
if use_sigmoid:
self.sigmoid = nn.Sigmoid()
def forward(self, pred: torch.Tensor, target: torch.Tensor):
if self.use_sigmoid:
pred = self.sigmoid(pred)
pred = pred.view(-1)
label = target.view(-1)
pos = torch.nonzero(label > 0).squeeze(1)
pos_num = max(pos.numel(),1.0)
mask = ~(label == -1)
pred = pred[mask]
label= label[mask]
scale_factor = (pred - label).abs().pow(self.beta)
loss = F.binary_cross_entropy(pred, label, reduction='none') * scale_factor
return loss.sum()/pos_num
```
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