CI: MPICH on CI

[gxyd]

Description

This is an initial attempt to resolve #31, currently probably wouldn't work and needs more work

[gxyd]

On this branch, for the below MPI program:

module init_mpi_mod
      implicit none
      integer :: nproc
      integer :: nprocsh
      integer :: iprocw
      integer :: iprocsh
      integer :: comm_shared
      contains
      subroutine init_mpi
            use mpi
            implicit none
            integer :: ierr,tcheck
            call MPI_Init_thread (MPI_THREAD_FUNNELED,tcheck,ierr)
            call MPI_Comm_size (MPI_COMM_WORLD,nproc,ierr)
            call MPI_Comm_rank (MPI_COMM_WORLD,iprocw,ierr)
            call MPI_Comm_split_type (MPI_COMM_WORLD,MPI_COMM_TYPE_SHARED,0, &
                                          MPI_INFO_NULL,comm_shared,ierr)
            call MPI_Comm_size (comm_shared,nprocsh,ierr)
            call MPI_Comm_rank (comm_shared,iprocsh,ierr)
      end subroutine
end module

program POT3D
      use mpi
      use init_mpi_mod
      implicit none
      integer :: ierr
      call init_mpi
      call MPI_Finalize (ierr)
end program pot3d

on it's execution with MPICH and Open MPI:

> mpif90 test.f90 -o test
> mpiexec -np 1 ./test
> echo $?
0

> $CC -I$CONDA_PREFIX/include -c src/mpi_wrapper.c; $FC -c src/mpi_c_bindings.f90; $FC -c src/mpi.f90
> $FC -c test.f90
> $FC mpi_wrapper.o mpi_c_bindings.o mpi.o test.o -o test -L$CONDA_PREFIX/lib -lmpi -Wl,-rpath,$CONDA_PREFIX/lib
> mpiexec -np 1 ./test

Abort(195654405) on node 0: Fatal error in internal_Comm_size: Invalid communicator, error stack:
internal_Comm_size(87): MPI_Comm_size(comm=0x2, size=0x16b271528) failed
internal_Comm_size(41): Invalid communicator

Above is the error I get with using MPICH, I extracted that program from POT3D repository.