# SumDif.pm
package SumDiff;

use strict;
use warnings;
use Data::Dumper;

sub mean {
    my $tt = 0;
    my $s = 0;
    while (defined($_ = shift))
    {
        $tt += $_;
        $s++;
    }
    return $tt/$s;
}

sub diffmap {
    my ($s1, $s2) = @_;

    my @diff;
    foreach my $i(0..$#$s1)
    {
        my $c1 = $s1->[$i];
        my $c2 = $s2->[$i];
        my @d = map { abs($c2->[$_] - $c1->[$_]) } (0..$#$c1);
        $diff[$i] = mean(@d);
    }
    return \@diff;
}

sub diffavg {
    return mean(@{diffmap(@_)});
}

1;