Is there any Fortran function to transpose 3D array?

Question

I need to transpose a 3D matrix in Fortran. I have a 3d array: V(111,222,333); I need to transpose it to V(333,111,222). Is there any function to do that in Fortran?

Answer 1

I hesitate to disagree with @IanBush and perhaps what follows is neither easy nor clear. The following statement will return a permutation of the array V. If I have got it right then the element at V(i,j,k) is sent to V_prime(k,i,j).

V_prime = RESHAPE(source=V, shape=[size(V,3),size(V,1),size(V,2)], order=[2,3,1])

Whether this creates the permutation OP asks for is a bit unclear, I'm not aware that there is a single definition of the transpose of an array of rank other than 2. Changing the order will produce different permutations.

This question is probably a duplicate of Fortran reshape - N-dimensional transpose. It is certainly worth reading the answers to that question which explain the use of reshape with order very well.

Answer 2

There is no routine that will do this simply. I would write some loops, that is often the easiest and clearest way.