view release on metacpan or  search on metacpan

lib/AI/CBR/Sim.pm  view on Meta::CPAN

sub sim_eq {
	return $_[0] eq $_[1] ? 1 : 0;
}


=head2 sim_set

Works for sets/lists of textual values.
Suitable when you are interested into overlap of the two sets.
Arguments are two array references with textual values.
Returns the number of elements in the intersection
divided by the number of elements in the union.
No third argument.

	sim_set([qw/a b c/], [qw/b c d/]); # returns 0.5
	sim_set([qw/a b c/], [qw/c/]); # returns 0.33

=cut

sub sim_set {
	my ($a, $b) = @_;
	return 1 if int @$a == 0 && int @$b == 0;
	return 0 unless int @$a && int @$b;
	my %a = map { ($_ => 1) } @$a;
	my $union = int keys %a;
	my $intersection = 0;
	map {
		$a{$_} ? $intersection++ : $union++
	} @$b;
	return $intersection / $union;
}


=head1 SEE ALSO

See L<AI::CBR> for an overview of the framework.


=head1 AUTHOR