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Simulator of Various Voting Algorithms in Manipulating Populations

Project description

SVVAMP

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Simulator of Various Voting Algorithms in Manipulating Populations

Features

  • Define profiles of voters with preferences over a set of candidates. Preferences can be generated by several probabilistic models, entered manually or imported from an external file.
  • Compute the result of several voting rules (ballots, winner, scores, etc).
  • Decide Condorcet notions.
  • Decide Independence of Irrelevant Alternatives.
  • Decide Individual Manipulation.
  • Decide Coalitional Manipulation and variants: Ignorant-Coalition Manipulation, Trivial Manipulation and Unison Manipulation.

Credits

This package was created with Cookiecutter and the francois-durand/package_helper_2 project template.

History

0.9.1 (2022-03-24): Compatibility issues

  • GeneratorProfileIanc is now compatible with Python < 3.8.
  • However, starting from this release, the official compatibility of SVVAMP is with Python 3.8, 3.9 and 3.10 (no support for Python 3.6 and 3.7).

0.9.0 (2022-03-24): GeneratorProfileIanc

  • Add GeneratorProfileIanc: profile generator for the Impartial, Anonymous and Neutral Culture.

0.8.3 (2021-08-01): Fix bug in ExperimentAnalyzer

  • Fix bug in ExperimentAnalyzer: for StudyRuleCriteria.numerical_criteria, the aggregation was not done properly.
  • Several cosmetic changes in ExperimentsCompiler.

0.8.2 (2021-07-29): Necessary coalition size to break IRV-Immunity

  • Add Profile.necessary_coalition_size_to_break_irv_immunity: necessary coalition size to break IRV immunity (for each candidate different from the IRV-immune candidate, if one exists).
  • Use this notion to improve the bound necessary_coalition_size_cm_ for RuleCondorcetAbsIRV, RuleCondorcetVtbIRV, RuleExhaustiveBallot, RuleICRV, RuleIRV, RuleIRVAverage, RuleSmithIRV, RuleTideman and RuleWoodall.

0.8.1 (2021-07-29): Use IRV-immune candidate for UM

  • RuleCondorcetAbsIRV, RuleCondorcetVtbIRV, RuleExhaustiveBallot, RuleICRV, RuleIRV, RuleIRVAverage, RuleSmithIRV, RuleTideman and RuleWoodall: add a precheck for UM based on the notion of IRV-immune candidate.

0.8.0 (2021-07-29): IRV-immune candidate

  • Introduce the notion of IRV-immune candidate. A candidate w is IRV-immune iff in any subset of candidates containing w, the plurality score of w is more than n_v / card(subset). This implies that in IRV (and most related rules), w is the winner and CM is impossible.
  • Add Profile.exists_irv_immune_candidate: whether there exists an IRV-immune candidate.
  • Add Profile.c_might_be_there_when_cw_is_eliminated_irv_style: whether a candidate c might be present in a round where the Condorcet winner is eliminated, IRV-style. In IRV (and most related rules), this condition is necessary to be able to cast CM in favor of c.
  • Use the above mentioned notions to improve the CM algorithm of RuleCondorcetAbsIRV, RuleCondorcetVtbIRV, RuleExhaustiveBallot, RuleICRV, RuleIRV, RuleIRVAverage, RuleSmithIRV, RuleTideman and RuleWoodall.
  • Add a UM precheck before CM in RuleSmithIRV, RuleTideman and RuleWoodall.

0.7.0 (2021-07-28): Better bounds for CM

  • Introduce a heuristic method to improve the bounds necessary_coalition_size_cm_ and sufficient_coalition_size_cm_ in the case of rules based on rankings.
  • Bug fix: in previous version (0.6.12), the IRV-CM precheck for UM was not activated for RuleCondorcetVtbIRV.

0.6.12 (2021-07-28): Fix bug in PluralityEliminationEngine

  • Fix bug in PluralityEliminationEngine: the previous version used to modify the original profile, which was not desired.
  • PluralityEliminationEngineProfileUM relies only on preferences_borda_rk and not on preferences_rk. This accelerates RuleSmithIRV.
  • RuleCondorcetAbsIRV and RuleCondorcetVtbIRV: before computing UM, we test whether IRV is CM. If not, then we can conclude that Condorcet-IRV is not CM, and in particular not UM.
  • Minor acceleration for RuleWoodall when the IRV winner is in the Smith set.

0.6.11 (2021-07-28): Accelerate ProfileUM

  • ProfileUM: implement a dedicated implementation for plurality_scores_rk and plurality_scores_ut.

0.6.10 (2021-07-28): PluralityEliminationEngine

  • Add PluralityEliminationEngine and its subclasses, PluralityEliminationEngineProfile and PluralityEliminationEngineProfileUM. This is used to speed up the computation of the winner for RuleExhaustiveBallot, RuleICRV, RuleIRVAverage, IRVDuels and RuleTideman.

0.6.8 (2021-07-27): Accelerate Exhaustive Ballot and some related rules

  • RuleExhaustiveBallot, RuleCondorcetAbsIRV and RuleCondorcetVtbIRV: accelerate counting the ballots. This also speeds up RuleIRV, which relies directly on RuleExhaustiveBallot.

0.6.7 (2021-07-27): Accelerations

  • The option sort_voters in Profile and related classes (such as GeneratorProfile and its subclasses) is now False by default.
  • Rule: accelerate exact IM, UM and CM (generic exact algorithms for ranking-based rules).
  • RuleBaldwin: accelerate counting the ballot and computing the winner (especially useful for exact UM).
  • RuleSTAR: accelerate TM.
  • RuleICRV, RuleIRVAverage, RuleSmithIRV, RuleTideman, RuleWoodall: accelerate CM.
  • Improve the management of options in RuleExhaustiveBallot and RuleIRV. In some (common) cases, it accelerates the computation of related voting rules (RuleCondorcetAbsIRV, etc).

0.6.6 (2021-07-27): Fix bug in ProfileUM

  • Fix bug: preferences_rk was an array of floats, it is now an array of integers.

0.6.5 (2021-07-27): Accelerations

  • Accelerate ProfileSubsetCandidates (used for IIA but also for some voting rules such as RuleTideman).
  • Add ProfileUM. This is used to speed up the generic exact algorithm for UM in the case of voting rules based on rankings.
  • RuleTideman: accelerate counting the ballot and computing the winner (especially useful for exact UM).
  • Accelerate preferences_ut_to_matrix_duels_ut.
  • Accelerate matrix_victories_to_smith_set.

0.6.4 (2021-07-27): Option “faster” for Maximin

  • RuleMaximin: implement cm_option=faster, which is as precise as fast to compute is_cm_, less precise to compute the bounds necessary_coalition_size_cm_ and sufficient_coalition_size_cm_, but a lot faster.

0.6.3 (2021-07-27): Accelerate ProfileSubsetCandidates

  • Profile now has a parameter preferences_borda_rk. At initialization, it can be given instead of preferences_rk.
  • ProfileSubsetCandidates: accelerate the initialization method.

0.6.2 (2021-07-27): Accelerate Maximin

  • Accelerate RuleMaximin.necessary_coalition_size_cm_ and RuleMaximin.sufficient_coalition_size_cm_.
  • Add RuleMaximin.sufficient_coalition_size_um_c_: number of manipulators that are sufficient (and necessary) for UM.

0.6.1 (2021-07-27): Accelerate Profile

  • Accelerate Profile: lazy evaluation of attributes preferences_rk, preferences_ut, preferences_borda_rk and preferences_borda_ut. This leads to a very significant acceleration for many methods (typically TM, UM and IIA, but also CM and IM for some voting rules).

0.6.0 (2021-07-26): ExperimentsCompiler

  • Add ExperimentsCompiler: draw plots and prepare tables based on the results computed by ExperimentAnalyzer on several experiments.
  • Accelerate RuleMajorityJudgment.necessary_coalition_size_cm_ and RuleMajorityJudgment.sufficient_coalition_size_cm_.

0.5.1 (2021-07-24): Fix PyPI deployment

  • Fix PyPI deployment.

0.5.0 (2021-07-24): Meta

  • This release focuses on “meta” tools that make the simulations easier.
    • Add StudyProfileCriteria: a set of criteria to study for the simulator about the profiles.
    • Add StudyRuleCriteria: a set of criteria to study for the simulator about one or several voting rules.
    • Add VotingRuleTasks: a set of tasks for the simulator, i.e. which voting rules with which options and which criteria about them.
    • Add ExperimentAnalyzer: a simulator designed to study small variations of a given profile.
  • New features for Rule:
    • Add check_option_allowed: check whether a pair (option, value) is allowed.
    • Add cm_power_index_: CM power index.
    • Add elects_condorcet_winner_rk_even_with_cm_: True if there is a Condorcet winner, she is elected by sincere voting and it is not CM.
    • Add is_tm_or_um_: True iff the profile is TM or UM.
    • Add log_: log corresponding to a particular manipulation method.
    • Add nb_candidates_cm_: number of candidates who can benefit from CM.
    • Add relative_social_welfare_w_: relative social welfare of the winner.
    • Add worst_relative_welfare_with_cm_: worst relative social welfare (sincere winner or candidate who can benefit from CM).
    • Each rule now has two class attributes full_name (name of the rule) and abbreviation (abbreviation of the name of the rule). For example, for RuleApproval, it is Approval Voting and AV respectively.
    • options_parameters is now a class attribute.
    • Accelerate the generic brute-force algorithm for exact UM when the rule is based on rankings.
  • New features for Profile:
    • Add property relative_social_welfare_c: relative social welfare of each candidate.
    • preferences_rk, preferences_ut, preferences_borda_rk and preferences_borda_ut are now properties.
  • Minor changes:
    • GeneratorProfile and all its subclasses now have a parameter sort_voters, which is simply passed to Profile when creating each profile.
    • ProfileGeneratorNoisedFile is renamed to GeneratorProfileNoisedFile, for the sake of consistency with other profile generators.
    • RULE_CLASSES is renamed to ALL_RULE_CLASSES.
    • Add utility functions indent and pseudo_bool_not.

0.4.3 (2021-07-21): Accelerations

  • Rule: accelerate trivial manipulation (TM) for rules based on rankings.
  • Profile: compute preferences_borda_ut only when needed. In particular, if often accelerates trivial manipulation (which relies on examining an alternate Profile object, with trivial strategy for manipulators).
  • RuleMajorityJudgment, RuleRangeVoting and RuleSTAR: accelerate the computation of the ballots.

0.4.2 (2021-07-20): Accelerate plurality_scores_ut

  • Accelerate Profile.plurality_scores_ut. As an example, for a profile with 65,000 voters and 5 candidates, the new version is approximately 10 times faster.

0.4.1 (2021-07-20): Fix Missing Subpackage in Deployment

  • Fix bug: in some distributions, some subpackages of Svvamp were not included.

0.4.0 (2021-07-19): Black, Copeland, Split Cycle, STAR

  • Add RuleBlack.
  • Add RuleCopeland.
  • Add RuleSplitCycle.
  • Add RuleSTAR.
  • In RuleRangeVoting and RuleMajorityJudgment, add an attribute allowed_grades: a list of the allowed grades.

0.3.0 (2021-07-16): New CM Algorithms for Smith-IRV-Like Rules

  • New CM algorithms for Smith-IRV-like rules:
    • New CM algorithms for RuleICRV, RuleSmithIRV, RuleTideman, RuleWoodall and RuleIRVAverage.
    • Add RuleIRV.example_ballots_cm_c_ and RuleIRV.example_ballots_cm_w_against_: examples of manipulating ballots (used as heuristic to manipulate Smith-IRV and similar rules).
    • In RuleCondorcetAbsIRV and RuleCondorcetVtbIRV, the former option almost_exact is renamed to very_slow, for the sake of consistency with Smith-IRV and similar voting rules.
  • Improve imports/exports:
    • ProfileFromFile can now import a CVR (cast vote record) file.
    • ProfileFromFile has a new parameter sort_candidates: sort the candidates from strongest to weakest (in a Black method sense).
    • Add Profile.to_csv: export the utilities to a csv file.
  • Add Rule.options: a dictionary with all the options of a rule.
  • Bug fixes:
    • Fix a major bug in RuleTideman: ballots were not counted correctly.
    • Fix a bug in RuleExhaustiveBallot and RuleIRV: applying a voting rule to a profile was able to change the options of another (related) rule.

0.2.0 (2021-07-13): Smith-IRV and Similar Voting Rules

  • A Profile object can now compute its Smith set (also called “top cycle”): smith_set_rk, smith_set_rk_ctb, smith_set_ut_abs, smith_set_ut_abs_ctb, smith_set_ut_rel, smith_set_ut_rel_ctb.
  • Add Smith-IRV.
  • Add Tideman’s rule.
  • Add Woodall’s rule.
  • Add constant RULE_CLASSES: list of all the rule classes.
  • Tools that are mostly dedicated to developers:
    • A global option allows to throw an error when an uncovered portion of code is reached.
    • Add Profile.to_doctest_string.
    • Add Rule._set_random_options.
    • Add Rule._random_instruction.

0.1.2 (2021-07-12): Fix Release Number

  • Fix release number.

0.1.1 (2021-07-12): Fix Deployment

  • Fix deployment on PyPI.

0.1.0 (2021-07-12): Complete Refactoring

  • Refactor the code completely. New architecture, especially for Rule (formerly Election), avoiding diamond inheritance. Rename most classes, properties and methods.
  • Cover the code with tests. Print a message when execution reaches an uncovered part of the code.
  • Fix some minor bugs.
  • Documentation in numpy style.
  • Tutorials are now Jupyter notebooks.
  • New rules: Kim-Roush and IRV-Average.

0.0.4 (2015-03-10): Fix a Bug in Plurality

  • Correct a minor bug in Plurality.IM (voters_IM is now updated).

0.0.3 (2015-02-28): Miscellaneous Minor Improvements

  • Rename functions and attributes with suffix _vtb to _rk.
  • Allow to define a population by both utilities and rankings.
  • Add shift to Euclidean box model.
  • Range voting / Majority Judgment: with a discrete set of grades, send to closest authorized grades.

0.0.2 (2015-02-16): SVVAMP’s Core Features

  • 8 population models and 23 voting systems.

0.0.1 (2015-02-14): First Release

  • First release on PyPI.

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