[FIXED] How to stack matrices with different size

Issue

I have a list of matrices with size of (63,32,1,600,600), when I want to stack it with torch.stack(matrices).cpu().detach().numpy() it's raising with error:

"stack expects each tensor to be equal size, but got [32, 1, 600, 600] at entry 0 and [16, 1, 600, 600] at entry 62". Is tried for resizing but it did not work. I appreciate any recommendations.

Solution

If I understand correctly what you're trying to do is stack the outputted mini-batches together into a single batch. My bet is that your last batch is partially filled (only has 16 elements instead of 32).

Instead of using torch.stack (creating a new axis), I would simply concatenate with torch.cat on the batch axis (axis=0). Assuming matrices is a list of torch.Tensors.

torch.cat(matrices).cpu().detach().numpy()

As torch.cat concatenates on axis=0 by default.

Answered By - Ivan