x = self.tanh(x) made this RuntimeError. But if this code line is changed with “x += bias”, no error exists.

Can anybody help me with error reasion?

RuntimeError: one of the variables needed for gradient computation has been modified by an inplace operation

```
def conv(in_channels, out_channels, kernel_size,
stride=1, groups=1, bias=True):
return nn.Conv2d(in_channels, out_channels, kernel_size,
stride=stride, padding=(kernel_size//2),
groups=groups, bias=bias)
class ESPCN(nn.Module):
def __init__(self, colors=3, channels=24, scale_factor=2):
super(ESPCN, sefl).__init__()
self.bias = Interpolation(scale_factor)
self.conv1 = conv(colors, channels, 5, 1)
self.conv2 = conv(channels, channels, 3, 1)
self.conv3 = conv(channels, (scale_factor**2)*colors, 3, 1)
self.PS = nn.PixelShuffle(scale_factor)
self.tanh = nn.Tanh()
def forward(self, x):
bias = self.bias(x)
x = F.relu(self.conv1(x), inplace=True)
x = F.relu(self.conv2(x), inplace=True)
x = F.relu(self.conv3(x), inplace=True)
x = self.PS(x)
x = self.tanh(x) #<--------
x += bias
return x
```