Transpose a column vector in torch

Question

I have a colum vector which I want to tranpose into row vector, I get the following error while doing it. Is there a way to tranpose 1 dimensional vectors in torch

th> bb
 1
 2
[torch.DoubleTensor of size 2]

                                                                      [0.0005s]
th> bb:t()
[string "_RESULT={bb:t()}"]:1: calling 't' on bad self (Tensor must have 2 dimensions at /tmp/luarocks_torch-scm-1-5379/torch7/generic/Tensor.c:590)
stack traceback:
    [C]: in function 't'
    [string "_RESULT={bb:t()}"]:1: in main chunk
    [C]: in function 'xpcall'

Answer 1

This is because your tensor has a dimension of 1. You can only take the transpose of a tensor with dimension 2.

In order to do this, first resize your tensor as

bb:resize(2,1)

After that, it should work:

th> bb:t()
 1  2

More generally, for a tensor with any other size, you can simply use:

bb:resize(bb:size(1),1)

Answer 2

for Transpose of 1d tensor you can do something like this:

let's say you have 1D tensor b:

import torch

a = torch.rand(1,10)
b = a[0,:]

and .t() not working for 1D

print(b)
#print(b.t()) # not going to work 1D

you can use one of the following option:

print(b.reshape(1,-1).t())
print(b.reshape(-1,1))

first line create 1*N matrix and then transpose it, and the second create N*1 matrix that transposed