my %hash = map {$pids[$_] => $location_topology[$_]} 0 .. $#pids;

   print "size of hash:  " . keys( %hash ) . ".\n";

#print @all_ids;

#print "@all_ids\n";

while ( my ($key, $value) = each(%hash) ) {
        for (my $i=0; $i<@all_ids; $i++)        {
                if ($all_ids[$i] eq $key)       {
                        print "$key => $value => $all_gc3s[$i]\n";
                }
#               if ($all_ids[$i] ne $key)       {
                        #print "$key\n";
#               }
}