Konstantin Kapitanov
and 1 contributors

NAME

Normalize - normalize scores between 0 and 1.

VERSION

Version 0.31

SYNOPSIS

        use Normalize;
        
        my %iq_rate = ('Professor' => 125.12, 'Bender' => 64, 'Dr. Zoidberg' => 28.6, 'Fray' => 13);
        my %weight_rate = ('Professor' => 70.2, 'Bender' => 600, 'Dr. Zoidberg' => 200, 'Fray' => 120);
        my $norm = Normalize->new('round_to' => 0.001);
        
        #larger score is better:
        $norm->normalize_to_max(\%iq_rate);
        print "\n#iq rate: larger iq is better:\n";
        foreach my $key (keys %iq_rate)
        {
                print "$key = $iq_rate{$key}\n";
        }
        
        #iq rate: larger iq is better:
        #1.000  Professor
        #0.512  Bender
        #0.229  Dr. Zoidberg
        #0.104  Fray
        
        #smaller score is better
        $norm->normalize_to_min(\%weight_rate, {min_default => 0.001});
        print "\n#skinny rate: smaller weight is better:\n";
        foreach my $key (sort {$weight_rate{$b} <=> $weight_rate{$a}} keys %weight_rate)
        {
                print "#$weight_rate{$key}\t$key\n";
        }
        ##skinny rate: smaller weight is better:
        #1.000  Professor
        #0.585  Fray
        #0.351  Dr. Zoidberg
        #0.117  Bender
        
        #SUMMARY RATE
        my %summary_score = map { $_ => $weight_rate{$_} + $iq_rate{$_} } keys %iq_rate;
        $norm->normalize_to_max( \%summary_score );
        print "\n#summary score:\n";
        foreach my $key (sort {$summary_score{$b} <=> $summary_score{$a}} keys %summary_score)
        {
                print "#$summary_score{$key}\t$key\n";
        }
        #summary score:
        #1.000  Professor
        #0.344  Fray
        #0.315  Bender
        #0.290  Dr. Zoidberg
        
        #Dr. Zoidberg - looser lobster! Quod erat demonstrandum

DESCRIPTION

This module gives you the ability to normalize score result sets. Sometimes a larger score is better and sometimes a smaller score is better. In order to compare the results from different methods? You need a way to normalize them: that is, to get them all within the same range and direction.

The normalization functions will take a hash ref {key => score} or array ref [score 1, score 2, ...scaore 3] and return the same ref, but whith scores between 0 and 1. Each score is scaled according to how close it to the best result, wich will always have a score of 1.

METHODS

new(%opts)

        Normalize->new(%opts) - constructor

%opts

round_to - default value 0.01. Rounding precision. For more info see Math::Round::Var

min_default - by default eq round_to value. Need for prevent delete on zero in normalize_to_min()

set(%params)

set object params

get(param_name)

get object param

normalize_to_min($score_set_data, %opts)

Each score is scaled according to how close it to the smaller result, wich will always have a score of 1. $score_set_data - hashref {key1 => score1, key2 => score2,..} or arrayref [score1, score2, ...] options:

        %opts = (
                                min_default => 0.01#by default = round_to value. Need for prevent delete on zero in normalize_to_min()
                        )
                        

return same data structure (hashref or arrayref)

normalize_to_max($score_set_data)

Each score is scaled according to how close it to the larger result, wich will always have a score of 1. $score_set_data - hashref {key1 => score1, key2 => score2,..} or arrayref [score1, score2, ...]

return same data structure (hashref or arrayref)

SEE ALSO

Math::Round::Var - Variations on rounding.

Idea for this module and normalization Algoritm from book "Programming Collective Intelligence: Building Smart Web 2.0 Applications By Toby Segaran)" http://books.google.com/books?id=fEsZ3Ey-Hq4C

AUTHOR

Konstantin Kapitanov aka Green Kakadu, perlovik at gmail dot com

http://wiki-linki.ru

BUGS

Please report any bugs or feature requests to bug-normalize at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Normalize. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Normalize

You can also look for information at:

ACKNOWLEDGEMENTS

COPYRIGHT & LICENSE

Copyright 2009 Konstantin Kapitanov, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.