! This file created from test/mpi/f77/coll/alltoallwf.f with f77tof90

! -*- Mode: Fortran; -*-

!

!  (C) 2003 by Argonne National Laboratory.

!      See COPYRIGHT in top-level directory.

!

      program main

      use mpi_f08

      integer ierr, errs

      integer i, intsize, ans, size, rank, color

      TYPE(MPI_Comm) comm, newcomm

      integer maxSize

      parameter (maxSize=32)

      integer scounts(maxSize), sdispls(maxSize)

      integer rcounts(maxSize), rdispls(maxSize)

      TYPE(MPI_Datatype) stypes(maxSize), rtypes(maxSize)

      integer sbuf(maxSize), rbuf(maxSize)

      errs = 0

      call mtest_init( ierr )

      call mpi_type_size( MPI_INTEGER, intsize, ierr )

! Get a comm

      call mpi_comm_dup( MPI_COMM_WORLD, comm, ierr )

      call mpi_comm_size( comm, size, ierr )

      if (size .gt. maxSize) then

         call mpi_comm_rank( comm, rank, ierr )

         color = 1

         if (rank .lt. maxSize) color = 0

         call mpi_comm_split( comm, color, rank, newcomm, ierr )

         call mpi_comm_free( comm, ierr )

         comm = newcomm

         call mpi_comm_size( comm, size, ierr )

      endif

      call mpi_comm_rank( comm, rank, ierr )

      if (size .le. maxSize) then

! Initialize the data.  Just use this as an all to all

         do i=1, size

            scounts(i) = 1

            sdispls(i) = (i-1)*intsize

            stypes(i)  = MPI_INTEGER

            sbuf(i) = rank * size + i

            rcounts(i) = 1

            rdispls(i) = (i-1)*intsize

            rtypes(i)  = MPI_INTEGER

            rbuf(i) = -1

         enddo

         call mpi_alltoallw( sbuf, scounts, sdispls, stypes, &

      &        rbuf, rcounts, rdispls, rtypes, comm, ierr )

!

! check rbuf(i) = data from the ith location of the ith send buf, or

!       rbuf(i) = (i-1) * size + i

         do i=1, size

            ans = (i-1) * size + rank + 1

            if (rbuf(i) .ne. ans) then

               errs = errs + 1

               print *, rank, ' rbuf(', i, ') = ', rbuf(i),  &

      &               ' expected ', ans

            endif

         enddo

      endif

      call mpi_comm_free( comm, ierr )

      call mtest_finalize( errs )

      call mpi_finalize( ierr )

      end