self.gamma*out considered as "in place" operation

[NGluna03]

Hi,
during the backward pass i'm facing the following error:
"RuntimeError: one of the variables needed for gradient computation has been modified by an inplace operation: [torch.cuda.FloatTensor [1]] is at version 1; expected version 0 instead. Hint: the backtrace further above shows the operation that failed to compute its gradient. The variable in question was changed in there or anywhere later. Good luck!"
Specifically the error occurs at the line out= self.gammaout +x and it seams to be due to "self.gammaout".
I also tried to change it to torch.mul(self.gamma, out) but it didn't solve the issue.
Do you have any idea on what the alternative solutions that I could try?