comment on

Just as quickly? Looks like (surprisingly, to me at least) ~9-10% faster on average.

use Benchmark qw( timethese cmpthese );
use List::Util qw( shuffle );

for my $max (qw( 100 200 500 1000 2000 5000 )) {
    print "results for $max elems\n";

    my @big_list = shuffle 1 .. $max;

    cmpthese(
        -1,
        {   plain_sort => sub {
                my @local = sort { $b <=> $a } @big_list;
            },
            reversed => sub {
                my @local = reverse sort { $a <=> $b } @big_list;
            },
        }
    );

    print "\n";
}

exit 0;

__END__
results for 100 elems
              Rate plain_sort   reversed
plain_sort 46849/s         --        -8%
reversed   50717/s         8%         --

results for 200 elems
              Rate plain_sort   reversed
plain_sort 20676/s         --       -12%
reversed   23424/s        13%         --

results for 500 elems
             Rate plain_sort   reversed
plain_sort 7657/s         --        -9%
reversed   8374/s         9%         --

results for 1000 elems
             Rate plain_sort   reversed
plain_sort 3490/s         --        -8%
reversed   3794/s         9%         --

results for 2000 elems
             Rate plain_sort   reversed
plain_sort 1599/s         --        -9%
reversed   1756/s        10%         --

results for 5000 elems
            Rate plain_sort   reversed
plain_sort 553/s         --       -10%
reversed   613/s        11%         --
[download]

This space reserved for the update when someone points out my obvious benchmark fau pas . . . :)

The cake is a lie.
The cake is a lie.
The cake is a lie.

In reply to Re^3: Predefined Sort by Fletch
in thread Predefined Sort by k_grdn

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


Perl: the Markov chain saw
	PerlMonks