PROGRAM MAIN
      INCLUDE 'mpif.h'
      INTEGER COMM, RESULT
      CALL MPI_INIT( IERR )
      CALL MPI_COMM_DUP(MPI_COMM_WORLD, COMM, IERR)
      CALL MPI_COMM_COMPARE(MPI_COMM_WORLD, COMM, RESULT, IERR)
      IF ( RESULT .EQ. MPI_IDENT ) THEN
         PRINT *, 'The two communicators are identical.'
      ELSE IF ( RESULT .EQ. MPI_CONGRUENT ) THEN
         PRINT *, 'The two communicators are congruent.'
      ELSE IF ( RESULT .EQ. MPI_SIMILAR ) THEN
         PRINT *, 'The two communicators are similar.'
      ELSE IF ( RESULT .EQ. MPI_UNEQUAL ) THEN
         PRINT *, 'The two communicators are unequal.'
      ELSE
         PRINT *, 'Unknown result.'
      ENDIF
      CALL MPI_FINALIZE(RC)
      STOP
      END