Dimensionality

x.size()                                  # return tuple-like object of dimensions
x = torch.cat(tensor_seq, dim=0)          # concatenates tensors along dim
y = x.view(a,b,...)                       # reshapes x into size (a,b,...)
y = x.view(-1,a)                          # reshapes x into size (b,a) for some b
y = x.transpose(a,b)                      # swaps dimensions a and b
y = x.permute(*dims)                      # permutes dimensions
y = x.unsqueeze(dim)                      # tensor with added axis
y = x.unsqueeze(dim=2)                    # (a,b,c) tensor -> (a,b,1,c) tensor
y = x.squeeze()                           # removes all dimensions of size 1 (a,1,b,1) -> (a,b)
y = x.squeeze(dim=1)                      # removes specified dimension of size 1 (a,1,b,1) -> (a,b,1)