anchor.diff:    request = MPI_REQUEST_NULL
     call MPI_IRecv(ab_ptr(otherID*offset+1), &
                    offset, &
  -                 MPI_FLOAT, &
  +                 MPI_REAL4, &
                    otherID, &
                    tag, &
                    gcomm, &
  
positive.code:   call flush(stdout)
    ab_sum = myid
    ab_gather = sum(ab_ptr)
    call MPI_Gather(ab_gather, 1, MPI_FLOAT, ab_sum, 1, MPI_FLOAT, 0, gcomm, ierr)
    if (myid == 0) then
      if (abs(ab_sum(myid) - ab_sum(otherID)) > 1.0e-8) stop "*** Wrong result ***"
    end if
  
negative.code:                  ierr)
    call MPI_ISend(ab_ptr(myid*offset+1), &
                   offset, &
                   MPI_REAL4, &
                   otherID, &
                   tag, &
                   gcomm, &
  