program main

!*****************************************************************************80
!
!! MAIN is the main program for VERSION.
!
!  Discussion:
!
!    VERSION is a simple MPI test program that gets the version of MPI.
!
!    Get the version and subversion of MPI.
!
!  Modified:
!
!    09 January 2004
!
!  Author:
!
!    John Burkardt
!
!  Reference:
!
!    William Gropp, Ewing Lusk, Anthony Skjellum,
!    Using MPI: Portable Parallel Programming with the
!    Message-Passing Interface,
!    Second Edition,
!    MIT Press, 1999,
!    ISBN: 0262571323.
!

!
!  Define MPI symbols by invoking the Fortran77-style include file:
!
  include 'mpif.h'
!
!  Define MPI symbols by a Fortran90 USE statement:
!
!  use mpi
!
! implicit none
!
  integer error
  integer, parameter :: master = 0
  integer num_procs
  integer subversion
  integer version
  integer world_id
!
!  Initialize MPI.
!
  call MPI_Init ( error )
!
!  Get MPI version and subversion.
!
  call MPI_Get_version ( version, subversion )
!
!  Get the number of processes.
!
  call MPI_Comm_size ( MPI_COMM_WORLD, num_procs, error )
!
!  Get the individual process ID.
!
  call MPI_Comm_rank ( MPI_COMM_WORLD, world_id, error )
!
!  Print a message.
!
  if ( world_id == master ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'VERSION - Master process:'
    write ( *, '(a)' ) '  FORTRAN90 version'
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) '  An MPI example program.'
    write ( *, '(a)' ) ' '
    write ( *, '(a,i8)' ) '  The number of processes is ', num_procs
    write ( *, '(a)' ) ' '
    write ( *, '(a,i8)' ) '  MPI version number is ', version
    write ( *, '(a,i8)' ) '  MPI subversion number is ', subversion
  end if

  write ( *, '(a)' ) ' '
  write ( *, '(a,i8,a)' ) '  Process ', world_id, ' says "Hello, world!"'

  if ( world_id == master ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'VERSION - Master process:'
    write ( *, '(a)' ) '  Normal end of execution: "Goodbye, world!".'
  end if
!
!  Shut down MPI.
!
  call MPI_Finalize ( error )

  stop
end