File Coverage

blib/lib/Chess/Elo.pm

Criterion	Covered	Total	%
statement	16	16	100.0
branch			n/a
condition			n/a
subroutine	4	4	100.0
pod	1	1	100.0
total	21	21	100.0

package Chess::Elo;

use strict;
use warnings;

use Exporter;

our @ISA = qw(Exporter);

# Items to export into callers namespace by default. Note: do not export
# names by default without a very good reason. Use EXPORT_OK instead.
# Do not simply export all your public functions/methods/constants.

# This allows declaration	use Chess::Elo ':all';
# If you do not need this, moving things directly into @EXPORT or @EXPORT_OK
# will save memory.
our %EXPORT_TAGS = ( 'all' => [ qw(
	elo
) ] );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our @EXPORT = qw(

);

our $VERSION = '1.0a';


# Preloaded methods go here.

our $factor  = 32;
our $divisor = 400;

sub elo {

  my ($A, $result, $B) = @_;

  my $Aexp = 10 ** ( ($B - $A) / $divisor ) ;


  my $A2 =
    $A + $factor * ( $result -
		     ( 1 /
		       ( 1 + $Aexp )
		     )
		   )
      ;

  my $Bexp = 10 ** ( ($A - $B) / $divisor ) ;

  $result = 1 - $result;

  my $B2 =
    $B + $factor * ( $result -
		     ( 1 /
		       ( 1 + $Bexp )
		     )
		   )
      ;

  ($A2, $B2)
}

1;
__END__