About pytorch tensor caculation

Question

I want to ask a question about torch calculation that if I only want to subtract the elements on the diagonal of the matrix without changing the elements in the remaining positions, is there any way to achieve it?

Answer 1

One way to do this is by getting the diagonal, doint the required operation on its elements and replacing the original one. Example code:

x = torch.rand(3, 3)
#get the original diagonal and for example substract 3
replaced_diag = x.diagonal() - 3
#replace the original diagonal
x.diagonal().copy_(replaced_diag)

For reference look at this: Replace diagonal elements with vector in PyTorch