view release on metacpan or  search on metacpan

lib/Algorithm/SlopeOne.pm  view on Meta::CPAN

    # Output:
    # \ {
    #     cuttlefish   0.25,
    #     nautilus     0.1,
    #     octopus      0.233333333333333
    # }

=head1 DESCRIPTION

Perl implementation of the I<Weighted Slope One> rating-based collaborative filtering scheme.

=head1 ATTRIBUTES

=head2 diffs

Differential ratings matrix.

=head2 freqs

Ratings count matrix.

=head1 METHODS

=head2 clear

Reset the instance.

=head2 add($userprefs)

Update matrices with user preference data, accepts a HashRef or an ArrayRef of HashRefs:

    $s->predict({ StarWars => 5, LOTR => 5, StarTrek => 3, Prometheus => 1 });
    $s->predict({ StarWars => 3, StarTrek => 5, Prometheus => 4 });
    $s->predict([
        { IronMan => 4, Avengers => 5, XMen => 3 },
        { XMen => 5, DarkKnight => 5, SpiderMan => 3 },
    ]);

=head2 predict($userprefs)

Recommend new items given known item ratings.

    $s->predict({ StarWars => 5, LOTR => 5, Prometheus => 1 });

=for Pod::Coverage new

=head1 TODO

Implement I<Non-Weighted> and I<Bi-Polar Slope One> schemes.

=head1 REFERENCES

=over 4

=item *

L<Slope One|https://en.wikipedia.org/wiki/Slope_One> - Wikipedia article

=item *

L<Slope One Predictors for Online Rating-Based Collaborative Filtering|http://lemire.me/fr/abstracts/SDM2005.html> - original paper

=item *

L<Collaborative filtering made easy|http://www.serpentine.com/blog/2006/12/12/collaborative-filtering-made-easy/> - Python implementation by Bryan O'Sullivan (primary reference, test code)

=item *

L<github.com/ashleyw/Slope-One|https://github.com/ashleyw/Slope-One> - Ruby port of the above by Ashley Williams (used to borrow test code)

=item *

L<Programming Collective Intelligence book|http://shop.oreilly.com/product/9780596529321.do> by Toby Segaran

=item *

L<Data Sets by GroupLens Research|http://www.grouplens.org/node/12>

=back

=head1 AUTHOR

Stanislaw Pusep <stas@sysd.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2014 by Stanislaw Pusep.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut