RuleCopeland¶
-
class
whalrus.
RuleCopeland
(*args, converter: whalrus.converters_ballot.converter_ballot.ConverterBallot = None, matrix: whalrus.matrices.matrix.Matrix = None, **kwargs)[source]¶ Copeland’s rule.
Parameters: - args – Cf. parent class.
- converter (ConverterBallot) – Default:
ConverterBallotToOrder
. - matrix (Matrix) – Default:
MatrixMajority
. - kwargs – Cf. parent class.
Examples
The score of a candidate is the number of victories in the majority matrix.
>>> rule = RuleCopeland(ballots=['a > b > c', 'b > a > c', 'c > a > b']) >>> rule.matrix_.as_array_ array([[Fraction(1, 2), 1, 1], [0, Fraction(1, 2), 1], [0, 0, Fraction(1, 2)]], dtype=object) >>> rule.scores_ {'a': 2, 'b': 1, 'c': 0}
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average_score_
¶ The average score.
Type: Number
-
average_score_as_float_
¶ The average score as a float. It is the same as
average_score_
, but converted to a float.Type: float
-
best_score_as_float_
¶ The best score as a float. It is the same as
RuleScore.best_score_
, but converted to a float.Type: float
-
compare_scores
(one: numbers.Number, another: numbers.Number) → int¶ Compare two scores.
Parameters: - one (object) – A score.
- another (object) – A score.
Returns: 0 if they are equal, a positive number if
one
is greater thananother
, a negative number otherwise.Return type: int
-
matrix_majority_
¶ The majority matrix. This is an alias for
matrix_
.Examples
>>> rule = RuleCopeland(ballots=['a > b > c', 'b > a > c', 'c > a > b']) >>> rule.matrix_majority_.as_array_ array([[Fraction(1, 2), 1, 1], [0, Fraction(1, 2), 1], [0, 0, Fraction(1, 2)]], dtype=object)
Type: Matrix
-
n_candidates_
¶ Number of candidates.
Type: int
-
scores_as_floats_
¶ Scores as floats. It is the same as
scores_
, but converted to floats.Type: NiceDict
-
strict_order_
¶ Result of the election as a strict order over the candidates. The first element is the winner, etc. This may use the tie-breaking rule.
Type: list
-
trailer_
¶ The “trailer” of the election. This is the last candidate in
strict_order_
and also the unfavorable choice of the tie-breaking rule incotrailers_
.Type: object
-
winner_
¶ The winner of the election. This is the first candidate in
strict_order_
and also the choice of the tie-breaking rule incowinners_
.Type: object
-
worst_score_as_float_
¶ The worst score as a float. It is the same as
RuleScore.worst_score_
, but converted to a float.Type: float