my %mythreads;
my $work_package = int($elements / $number_threads + 0.5);
my @ReturnData :shared;
my $start = 0;
my $stop = $start + $work_package * $files - 1;
$stop = $elements * $files - 1 if ($stop >= $elements * $files);

for (my $i = 0; $i < $number_threads; $i++) {
	$mythreads{$i} = threads->create(\&do_work);
	$start = $stop + 1;
	$stop += $work_package * $files;
	$stop = $elements * $files - 1 if ($stop >= $elements * $files);
}
# collect data
foreach (sort(keys(%mythreads))) {
	$mythreads{$_}->join();
}