Here's an example which uses the CPAN subject categories for the training set, and then classifies modules according to which category they probably best fit into:
use strict;
use warnings;
require AI::Categorizer;
require AI::Categorizer::Learner::NaiveBayes;
require AI::Categorizer::Document;
require AI::Categorizer::KnowledgeSet;
require Lingua::StopWords;
# set up features:
# - give different weights to subjects and bodies
# - use stop words
my %features = (content_weights => {subject => 2,
body => 1},
stopwords => Lingua::StopWords::getStopWords('en'),
stemming => 'porter',
);
# this is the raw data to train with, which associates
# numerical categories with subjects and bodies
my $chaps =
{ 6 => {subject => q{Data Type Utilities},
body => q{Date Time Math List Tree Algorithm Sort},
},
10 => {subject => q{File Names Systems Locking},
body => q{Directory Dir Stat cwd},
},
12 => {subject => q{Opt Arg Param Proc},
body => q{Option Argument Argv Config Getopt},
},
14 => {subject => q{Security and Encryption},
body => q{Authentication Crypt Digest PGP Des},
},
15 => {subject => q{World Wide Web HTML HTTP CGI},
body => q{WWW Apache MIME Kwiki URI URL},
},
17 => {subject => q{Archiving and Compression},
body => q{tar gzip gz zip bzip},
},
18 => {subject => q{Images Pixmaps Bitmaps},
body => q{Chart Graphic},
},
19 => {subject => q{Mail and Usenet News},
body => q{Sendmail NNTP SMTP IMAP POP3 MIME},
},
};
# create documents from $chaps to train with
my $docs;
foreach my $cat(keys %$chaps) {
$docs->{$cat} = {categories => [$cat],
content => {subject => $chaps->{$cat}->{subject},
body => $chaps->{$cat}->{body},
},
};
}
my $c =
AI::Categorizer->new(
knowledge_set =>
AI::Categorizer::KnowledgeSet->new( name => 'CSL'),
verbose => 1,
);
while (my ($name, $data) = each %$docs) {
$c->knowledge_set->make_document(name => $name, %$data, %features);
}
my $learner = $c->learner;
$learner->train;
# this is a test data set to categorize,
# based on the training done above
my $test_set =
{'Math::Complex' => {content =>
{subject => q{Math},
body => q{Complex number data type}
} },
'Archive::Zip' => {content =>
{subject => q{Compression},
body => q{Interface to ZIP archive files}
} },
'Apache2::URI' => {content =>
{subject => q{Apache},
body => q{Perl API for manipulating URIs}
} },
'MIME::Lite' => {content =>
{subject => q{Mail},
body => q{Create MIME/SMTP mails w/attachements}
} },
};
# see what category each element of $test_set gets put into,
# using a threshold score of 0.9
my $threshold = 0.9;
while (my ($name, $data) = each %$test_set) {
my $doc = AI::Categorizer::Document->new(name => $name,
content => $data->{content},
%features);
my $r = $learner->categorize($doc);
$r->threshold($threshold);
my $b = $r->best_category;
next unless $r->in_category($b);
printf("%s is in category %d, with score %.3f\n",
$name, $b, $r->scores($b));
}
This produces
Archive::Zip is in category 17, with score 0.998
Apache2::URI is in category 15, with score 0.917
MIME::Lite is in category 19, with score 1.000
Math::Complex is in category 6, with score 0.997
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