Programming/Perl
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Contents
Programming Details
Perl is a family of high-level, general-purpose, interpreted, dynamic programming languages. The languages in this family presently are Perl 5 and Perl 6.
When programming with Perl in a HPC environment you will need to change the first line from:
#!/usr/bin/perl
To
#!/usr/bin/env perl
Programming example
Non MPI program
#!/usr/bin/env perl
#
# VIPER - HPC
# ICTD Department
# Hull University
#
# Written by DBird 25/12/2017
# ---------------- Modules ------------------------------------------
use strict; # perform error checking
# ---------------- Variables ----------------------------------------
my ($i);
# -------------------------------------------------------------------
# ---------------- Main Program -------------------------------------
# -------------------------------------------------------------------
for($i = 0; $i < 1000; $i++)
{
print "A-->$i\n";
}
# ---------------- finish up and exit -------------------------------
exit;
Note this program does not contain any MPI directives and is shown simply for demonstrative purposes. Although PERL does support MPI, it's implementation is quite limited compared to C, C++ and Fortran.
MPI program
#!/usr/bin/env perl
#
# VIPER - HPC
# ICTD Department
# Hull University
#
# Written by DBird 25/12/2017
use Parallel::MPI::Simple;
MPI_Init();
my $rank = MPI_Comm_rank(MPI_COMM_WORLD);
if ($rank == 1)
{
my $msg = "Hello, I'm $rank";
MPI_Send($msg, 0, 123, MPI_COMM_WORLD);
}
else
{
my $msg = MPI_Recv(1, 123, MPI_COMM_WORLD);
print "$rank received: '$msg'\n";
}
MPI_Finalise();
exit;
Running the program
The program could be executed in the following way for test purposes on the login node:
[username@login01 ~]$ module add perl/5.24.0 [username@login01 ~]$ perl testPerl.pl
Batch example
#!/bin/bash #SBATCH -J openPERL-node #SBATCH -N 1 #SBATCH --ntasks-per-node 20 #SBATCH -o %N.%j.%a.out #SBATCH -e %N.%j.%a.err #SBATCH -p compute #SBATCH --exclusive echo $SLURM_JOB_NODELIST module purge module add perl/5.24.0 export I_MPI_DEBUG=5 export I_MPI_FABRICS=shm:tmi export I_MPI_FALLBACK=no perl /home/user/PERL/demoPERL.pl
[username@login01 ~]$ sbatch demoPERL.job Submitted batch job 289352