How to alternatively concatenate pytorch tensors?

Question

Pytorch provides API to concatenate tensors, like cat, stack. But does it provide any API to concatenate pytorch tensors alternatively?

For example，

suppose input1.shape = C*H*W, a1.shape = H\*W, and output.shape = (3C)*H*W

This can be achieved using a loop, but I am wondering if any Pytorch API can do this

Answer 1

I will try to do it with small example:

input1 = torch.full((3, 3), 1)
input2 = torch.full((3, 3), 2)
input3 = torch.full((3, 3), 3)

out = torch.concat((input1,input2, input3)).T.flatten()
torch.stack(torch.split(out, 3), dim=1).reshape(3,-1)

#output

tensor([[1, 2, 3, 1, 2, 3, 1, 2, 3],
        [1, 2, 3, 1, 2, 3, 1, 2, 3],
        [1, 2, 3, 1, 2, 3, 1, 2, 3]])