#!/usr/bin/perl
use warnings;
use strict;

use File::Stream;

my $m=3;
my $n=4;
my $filehandle;

open ($filehandle, '<',  "testfile") || die "can't open the testfile";


my $stream = File::Stream->new($filehandle);
$/ = qr/\s+/;


my @a;
my @ia;
my @ja;

my $nnz=1;

my $x=0;
my $y=0;
my $value;
while ($value=<$stream>) {
    $value=~s/\s//g; #because chomp doesn't work with File::Stream
    $x++;
    if ($y==0 or $x>$n) { 
	$x=1; $y++;
	push @ia,$nnz;
    }
    if ($value) {
	push @a, $value;
	push @ja, $x;
	$nnz++;
    }
}
push @ia,$nnz;

if ($y!=$m and $x!=$m) {
    print "Wrong number of values in array data\n";
}

print 'A= [ ', join(' ',@a),"]\n";
print 'IA= [ ', join(' ',@ia),"]\n";
print 'JA= [ ', join(' ',@ja),"]\n";