Vote::Count::Matrix
Condorcet Pairwise Methods require a Win-Loss Matrix. This object takes an RCV BallotSet with an optional Active list and returns the Matrix as an object. The object is capable of Scoring itself, Calculating a Smith Set, and identifying Condorcet Winners and Losers.
my $Matrix = Vote::Count::Matrix->new( 'BallotSet' => $myVoteCount->BallotSet() ); my $Scores = $Matrix->ScoreMatrix(); my %DominantSet = $Matrix->SmithSet()->%*; my $CondorcetWinner = $Matrix->CondorcetWinner();
A tie breaker may be specified by setting the Tie::Breaker attribute, see the Tie::Breaker module for more information. If using Range Ballots 'none' and 'approval' are the only currently supported options.
Parameters:
A Ballot Set reference as generated by ReadBallots, which can be retrieved from a Vote::Count object via the ->BallotSet() method.
Both Ranked Choice and Range BallotSets are supported.
A hash reference with active choices as the keys. The default value is all of the choices defined in the BallotSet.
Has the logging methods of L.
Returns a MarkDown formatted table with the wins losses and ties for each Active Choice as text.
Returns a MarkDown formatted table with the votes for all of the pairings.
Returns the results of the pairing of two choices as a hashref.
{ 'FUDGESWIRL' => 6, 'loser' => "STRAWBERRY", 'margin' => 2, 'STRAWBERRY' => 4, 'tie' => 0, 'winner' => "FUDGESWIRL" }
Returns the winner of the pairing of two choices. If there is no Winner it returns a false value (empty string).
Returns a HashRef of the choices and their Matrix Scores. The scoring is 1 for each win, 0 for losses and ties. In the event a choice has ties but no wins their score will be .001. Where N is the number of choices, a Condorcet Winner will have a score of N-1, a Condorcet Loser will have a score of 0. Since a choice with at least one tie but no wins is not defeated by all other choices they are not a Condorcet Loser, and thus those cases are scored with a near to zero value instead of 0. Methods that wish to treat no wins but tie case as a Condorcet Loser may test for a score less than 1.
Returns the ScoreMatrix as a markdown compatible table.
Returns an array of the choice or choices with the fewest wins.
Eliminates all Condorcet Losers from the Matrix Object's Active list. Returns a hashref. Takes an optional true false argument (default is false) to include choices that have tied but not won in the elimination.
{ verbose => 'verbose message', terse => 'terse message', eliminated => [ eliminated choices ], eliminations => number of eliminated choices, };
Returns either the Condorcet Winner or an empty string if there is none.
Finds the innermost Smith Set (Dominant Set). [ assistance in finding proof of the algorithm used would be appreciated so it could be correctly referenced in this documentation ]. A Dominant Set is a set which defeats all choices outside of that set. The inner Smith Set is the smallest possible Dominant Set.
Returns a hashref with the keys as the choices of the Smith Set.
Reset Active list to the choices list of the BallotSet.
Returns the greatest loss for a choice $MyMatrix->GreatestLoss( $A ).
$MyMatrix->GreatestLoss( $A )
Returns a RankCount object of the Greatest Loss for each choice.
BUG TRACKER
https://github.com/brainbuz/Vote-Count/issues
AUTHOR
John Karr (BRAINBUZ) brainbuz@cpan.org
CONTRIBUTORS
Copyright 2019-2021 by John Karr (BRAINBUZ) brainbuz@cpan.org.
LICENSE
This module is released under the GNU Public License Version 3. See license file for details. For more information on this license visit http://fsf.org.
SUPPORT
This software is provided as is, per the terms of the GNU Public License. Professional support and customisation services are available from the author.
To install Vote::Count, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Vote::Count
CPAN shell
perl -MCPAN -e shell install Vote::Count
For more information on module installation, please visit the detailed CPAN module installation guide.