Question

I have the following minimal example:

      program main

      double precision, dimension(3)   :: rankone
      double precision, dimension(3,1) :: ranktwo

      double precision, dimension(3)   :: output

      rankone = 1
      ranktwo = 2

      output = rankone + ranktwo

      print *, 'output: ', output

      end program main

Is there a function like squeeze in Matlab that removes the singleton dimension from the variable ranktwo. I’m looking for something like

      output = rankone + squeeze(ranktwo)

If not, is there any workaround for this setting?

Are there any differences between the various versions of Fortran regarding this problem?

Answer 1

Try this

output = rankone + reshape(ranktwo,[3])

then look at the documentation for reshape to see what is going on. You could also write

output = rankone + ranktwo(:,1)

which slices a 1D array out of ranktwo. In my experience reshape usually causes an array copy so there may be a memory-use-efficiency argument for preferring the second version.

No, there are no differences between Fortran versions regarding this problem, a 3×1 array is not the same shape as a 1D array of length 3.