I have a symmetric tensor of size `[B, N, N, C]`

. I would like to eliminate the diagonal elements. I was wondering what is the most efficient way to do this?

My solution:

Use

```
idx1 = torch.triu_indices(N, N, 0)
idx2 = torch.triu_indices(N, N, 1)
```

Then turn them into lists, subtract to get diagonal indices. Then use them to subtract diagonal term from the original tensor. But I’m wondering

- Would turning indices into list break backprop?
- Also, I’m not sure if this is the most efficient way to do this.