use Math::Random::MT qw(srand rand);
sub seed_prng {
  # Seed the pseudo random number generator with a random or specified seed
  # Returns what seed value is used
  my ($seed) = shift;
  if (not defined $seed) {
    # Want to produce an random unsigned 32-bit integer to feed to
    # Math::Random::MT::srand(). That means, first seed srand() with a temporary
    # seed that varies quickly in time so we don't get twice the same seed if we
    # request several seeds in a short interval of time.
    my $tmp_seed = time ^ ($$ + ($$ << 15)); # shown in srand's doc
    srand($tmp_seed);
    my $max = int(2**32-1); # Largest unsigned 32-bit integer
    $seed = int(rand($max+1)); # An integer between 0 and $max
  }
  srand($seed);
  return $seed;
}