This finds the smallest difference between any two random values.

use strict;
use warnings;
use List::MoreUtils qw(uniq);
use List::Util qw(min);

my @samples = sort { $a <=> $b } uniq map {rand} 1..3000;

print scalar @samples, " unique samples.\n";

print "The minimum difference is ", min map { $samples[$_] - $samples[
+$_-1] } 1..$#samples;

__END__
2861 unique samples.
The minimum difference is 3.0517578125e-005
[download]