Hello, Parallel::MPI

hello_parallel_mpi_simple.pl

#!/usr/bin/env perl

use 5.010;
use Parallel::MPI::Simple;

$total = 0;

MPI_Init();


$rank = MPI_Comm_rank( MPI_COMM_WORLD );
$size = MPI_Comm_size( MPI_COMM_WORLD );

$host = `hostname`;

say "I am process $rank of $size at $host";

MPI_Barrier( MPI_COMM_WORLD );

my $total = MPI_Reduce( $rank, sub { $_[0] + $_[1] } , MPI_COMM_WORLD );
if ( $rank == 0 ) {
  say $total;
}

if ( $rank < $size-1 ) {
  MPI_Send( $rank, $rank+1, 0, MPI_COMM_WORLD );
}

MPI_Barrier( MPI_COMM_WORLD );

if ( $rank > 0 ) {
  my $received_data = MPI_Recv( $rank-1, 0, MPI_COMM_WORLD );
  say "my rank is $rank and receive data from $received_data";
}

MPI_Finalize();