Re: Benchmark Schwartzian Transform

[Laszlo]

Third improvement, which returned poorer results, for Schwartzian but posting it, maybe someone will spot an error. :-)

#! /usr/bin/perl -w
#############################################################
# File   :  Perl Schwartzian Transform Demo.pl
# History:    16-Mar-2015 Laszlo first version.
#            19-Mar-2015 Laszlo, improved a little bit.
#            19-Mar-2015 Laszlo, did the benchmarking which returned p
+oorer results...
#############################################################
# A script to demonstrate and measure the Schwartzian Transform.
#############################################################
# Some form of documentation:
# http://www.perlmonks.org/?node_id=1120222

use warnings;
use strict;
use Time::HiRes;
use Benchmark;
use List::Util;

my $maxNumberValue = 100;
my $intSampleSize = 32000;
my @unsortedIntArray = map { int(rand($maxNumberValue)) } ( 1..$intSam
+pleSize );

my $compareAsNumberFunction = sub { return $_[0] <=> $_[1]; };
my $compareAsStringFunction = sub { return $_[0] cmp $_[1]; };

my $noTransformFunction = sub { return shift; };
my $sleepyNoTransformFunction = sub { Time::HiRes::usleep(1); return s
+hift; };
my $returnLengthFunction = sub { return length(shift); };

schwartzianSortVsRegularSort(\@unsortedIntArray, $compareAsNumberFunct
+ion, $noTransformFunction);
schwartzianSortVsRegularSort(\@unsortedIntArray, $compareAsStringFunct
+ion, $noTransformFunction);
schwartzianSortVsRegularSort(\@unsortedIntArray, $compareAsNumberFunct
+ion, $sleepyNoTransformFunction);

my @chars = ("A".."Z", "a".."z");
my $maxStringLength = 300;
my $stringSampleSize = 32000;
my @unsortedStringArray = map { (sub { 
                my $string; 
                $string .= $chars[rand @chars] for 1..(int(rand($maxSt
+ringLength)) + 1); 
                return $string;
            })->(); } ( 1..$stringSampleSize );

schwartzianSortVsRegularSort(\@unsortedStringArray, $compareAsStringFu
+nction, $noTransformFunction);
schwartzianSortVsRegularSort(\@unsortedStringArray, , $compareAsNumber
+Function, $returnLengthFunction);

sub schwartzianSortVsRegularSort
{
    my @unsortedArray_in = @{$_[0]};    
    my $compareFunction_in = $_[1];
    my $transform4Sort_in = $_[2];
    
    print "Collection of size: " . +@unsortedArray_in . " \n";
    
    Benchmark::cmpthese(10, 
    {
        regular => sub 
        {
            my @regularSorted = sort { $compareFunction_in->($transfor
+m4Sort_in->($a), $transform4Sort_in->($b)) } List::Util::shuffle @uns
+ortedArray_in;
        },
        schwartzian => sub
        {
            my @schwartzianSorted = map  { $_->[0] }
                sort { $compareFunction_in->($a->[1], $b->[1]) }
                map  { [$_, $transform4Sort_in->($_)] }
                List::Util::shuffle @unsortedArray_in;
        }
    });    
}