spread function compiler bug with gfortran-8

[Joseph Parker]

Currently some of the tests fail with:

Fortran runtime error: rank mismatch in spread()
[snip]
#4  0xd6c8d9 in __dist_fn_MOD_get_init_field
    at /home/joseph/code/gs2/dist_fn.f90:7056

This appears to be a compiler bug in 8.1.0 (for me) and 8.1.1 for this SO. I recommend the comments to answer 1 as an exemplar of constructive discourse...

I think we should just bump the version of gfortran used in the docker image.

[Joseph Parker]

PS: Example program which fails with gfortran 8 and works with gfortran 7:

PROGRAM test_spread
  integer :: ntgrid = 2
  integer :: ntheta0 = 3
  integer :: naky = 5
  integer, dimension (:,:,:), allocatable :: bmagsp
  integer, dimension (:), allocatable :: bmag

  allocate(bmagsp(-ntgrid:ntgrid,ntheta0,naky))
  allocate(bmag(-ntgrid:ntgrid))

  bmag = (/ 1, 2, 3, 4 /)

  bmagsp=spread(spread(bmag,2,ntheta0),3,naky)

  write(*,*) bmagsp

END PROGRAM

[Peter Hill]

I can confirm this is fixed in 8.2 -- I'm in favour of just bumping the version used in docker image, as you suggest

[Joseph Parker]

Thanks! 8.1.0 is the version in Ubuntu 16.04.

[Joseph Parker]

Compiler updated to gfortran 8.2 in automated-testing branch.