I want to implement this function: x / ( 1 - e^(-x )). However, after I’ve done that, all of my loss became nan. I don’t know what happen to me

and here is my code:

```
class MyAttn(nn.Module):
def __init__(self, channel, reduction=16):
super(MyAttn, self).__init__()
self.avg_pool = nn.AdaptiveAvgPool2d(1)
self.fc = nn.Sequential(
spectral_norm(nn.Linear(channel, channel // reduction, bias=False)),
nn.ReLU(inplace=True),
spectral_norm(nn.Linear(channel // reduction, channel, bias=False)),
)
def forward(self, x):
b, c, _, _ = x.size()
y = self.avg_pool(x).view(b, c)
y = self.fc(y)
energy = y / (1 - torch.exp(-y))
energy = energy.view(b, c, 1, 1)
return x * energy.expand_as(x)
```