XyyToProfile

class poisson_approval.XyyToProfile(cls, left_ranking, right_ranking, d_type_fixed_share=None, **kwargs)[source]

Map a point (x, y1, y2) to a profile (for binary plots).

Parameters

  • cls (class) – ProfileDiscrete or ProfileNoisyDiscrete.

  • left_ranking (str) – A ranking, whose share is maximal on the left (resp. on the right).

  • right_ranking (str) – A ranking, whose share is maximal on the left (resp. on the right).

  • d_type_fixed_share (dict) – Key: a type that is suitable for the kind of profile used. Value: a share of voters.

  • kwargs – Other keyword arguments are passed to the profile. E.g. voting_rule, ratio_fanatic, etc.

Notes

An XyyToProfile object is a callable. When called, it takes three parameters x, y1, y2 in the interval [0, 1]. It outputs the profile defined by:

  • The class is given by cls,

  • According to d_type_fixed_share, some types are assigned fixed shares of voters.

  • The other voters are distributed between left_ranking and right_ranking, in respective proportions that are given by 1 - x and x.

  • The voters of left_ranking have a utility y1 for their second candidate.

  • The voters of right_ranking have a utility y2 for their second candidate.

Examples

Typical usage:

>>> xyy_to_profile = XyyToProfile(
...     ProfileNoisyDiscrete,
...     d_type_fixed_share={('abc', 0.4, 0.01): Fraction(2, 11)},
...     left_ranking='bca', right_ranking='cab',
...     noise=0.01)
>>> profile = xyy_to_profile(x=Fraction(4, 9), y1=0.7, y2=0.9)
>>> print(profile)
<abc 0.4 ± 0.01: 2/11, bca 0.7 ± 0.01: 5/11, cab 0.9 ± 0.01: 4/11>

The types with variable share and fixed share may overlap:

>>> xyy_to_profile = XyyToProfile(
...     ProfileNoisyDiscrete,
...     d_type_fixed_share={('abc', 0.4, 0.01): Fraction(2, 11)},
...     left_ranking='abc', right_ranking='cab',
...     noise=0.01)
>>> profile = xyy_to_profile(x=Fraction(4, 9), y1=0.4, y2=0.9)
>>> print(profile)
<abc 0.4 ± 0.01: 7/11, cab 0.9 ± 0.01: 4/11> (Condorcet winner: a)