Merge pull request #96 from wesholliday/main

Added positive_involvement to voting method properties, added Schwartz sequential dropping algorithm for Beat Path

docs/source/scoring_methods.md

@@ -120,7 +120,15 @@ One problem with the above code is that the name of the scoring rule is "Scoring
 
 ```{eval-rst}
 
-.. autofunction:: pref_voting.scoring_methods.anti_plurality(profile, curr_cands = None)
+.. autofunction:: pref_voting.scoring_methods.anti_plurality
+
+```
+
+## Dowdall
+
+```{eval-rst}
+
+.. autofunction:: pref_voting.scoring_methods.dowdall
 
 ```
 

pref_voting/c1_methods.py

@@ -23,7 +23,9 @@
 condorcet_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=False,
-    pareto_dominance=False,)
+    pareto_dominance=False,
+    positive_involvement=False,
+    )
 @vm(name = "Condorcet",
     properties = condorcet_properties,
     input_types = [ElectionTypes.PROFILE, ElectionTypes.PROFILE_WITH_TIES, ElectionTypes.MAJORITY_GRAPH, ElectionTypes.MARGIN_GRAPH])
@@ -75,7 +77,9 @@ def condorcet(edata, curr_cands = None):
 copeland_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Copeland",
     properties = copeland_properties,
     input_types = [ElectionTypes.PROFILE, ElectionTypes.PROFILE_WITH_TIES, ElectionTypes.MAJORITY_GRAPH, ElectionTypes.MARGIN_GRAPH])
@@ -162,7 +166,9 @@ def copeland_ranking(edata, curr_cands=None, local=True, tie_breaking=None):
 llull_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Llull",
     properties = llull_properties,
     input_types = [ElectionTypes.PROFILE, ElectionTypes.PROFILE_WITH_TIES, ElectionTypes.MAJORITY_GRAPH, ElectionTypes.MARGIN_GRAPH])
@@ -228,6 +234,7 @@ def right_covers(dom, c1, c2):
     condorcet_winner=True,
     condorcet_loser=True,
     pareto_dominance=True,)
+
 @vm(name = "Uncovered Set",
     properties = uc_gill_properties,
     input_types = [ElectionTypes.PROFILE, ElectionTypes.PROFILE_WITH_TIES, ElectionTypes.MAJORITY_GRAPH, ElectionTypes.MARGIN_GRAPH])
@@ -544,7 +551,9 @@ def uc_mckelvey(edata, curr_cands = None):
 top_cycle_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Top Cycle",
     properties = top_cycle_properties,
     input_types = [ElectionTypes.PROFILE, ElectionTypes.PROFILE_WITH_TIES, ElectionTypes.MAJORITY_GRAPH, ElectionTypes.MARGIN_GRAPH])
@@ -645,7 +654,9 @@ def top_cycle_defeat(edata, curr_cands = None):
 gocha_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "GOCHA",
     properties = gocha_properties,
     input_types = [ElectionTypes.PROFILE, ElectionTypes.PROFILE_WITH_TIES, ElectionTypes.MAJORITY_GRAPH, ElectionTypes.MARGIN_GRAPH])

pref_voting/combined_methods.py

@@ -21,7 +21,9 @@
 daunou_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Daunou",
     properties = daunou_properties,
     input_types = [ElectionTypes.PROFILE])
@@ -68,7 +70,9 @@ def daunou(profile, curr_cands=None):
 blacks_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Blacks",
     properties = blacks_properties,
     input_types = [ElectionTypes.PROFILE])
@@ -112,7 +116,9 @@ def blacks(profile, curr_cands=None):
 smith_irv_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Smith IRV",
     properties = smith_irv_properties,
     input_types = [ElectionTypes.PROFILE])
@@ -151,7 +157,9 @@ def smith_irv(profile, curr_cands=None):
 smith_irv_put_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Smith IRV PUT",
     properties = smith_irv_put_properties,
     input_types = [ElectionTypes.PROFILE])
@@ -190,7 +198,10 @@ def smith_irv_put(profile, curr_cands=None):
 condorcet_irv_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
+
 @vm(name = "Condorcet IRV",
     properties = condorcet_irv_properties,
     input_types = [ElectionTypes.PROFILE])
@@ -231,7 +242,9 @@ def condorcet_irv(profile, curr_cands=None):
 condorcet_irv_put_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Condorcet IRV PUT",
     properties = condorcet_irv_put_properties,
     input_types = [ElectionTypes.PROFILE])
@@ -324,7 +337,9 @@ def _vm(edata, curr_cands=None):
 condorcet_plurality_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=False,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name = "Condorcet Plurality",
     properties = condorcet_plurality_properties,
     input_types = [ElectionTypes.PROFILE])
@@ -343,12 +358,14 @@ def condorcet_plurality(profile, curr_cands = None):
     return _compose(condorcet, plurality)(profile, curr_cands=curr_cands)
 
 
-smith_minimax_plurality_properties = VotingMethodProperties(
+smith_minimax_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=True,
+    )
 @vm(name="Smith-Minimax",
-    properties=smith_minimax_plurality_properties,
+    properties=smith_minimax_properties,
     input_types=[ElectionTypes.PROFILE, ElectionTypes.PROFILE_WITH_TIES, ElectionTypes.MARGIN_GRAPH])
 def smith_minimax(edata, curr_cands = None):
     """Return the Minimax winner after restricting to the Smith set.
@@ -367,7 +384,9 @@ def smith_minimax(edata, curr_cands = None):
 copeland_local_borda_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name="Copeland-Local-Borda",
     properties=copeland_local_borda_properties,
     input_types=[ElectionTypes.PROFILE,  ElectionTypes.MARGIN_GRAPH])
@@ -414,7 +433,9 @@ def _vm(profile, curr_cands=None):
 copeland_global_borda_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name="Copeland-Global-Borda",
     properties=copeland_global_borda_properties,
     input_types=[ElectionTypes.PROFILE])
@@ -505,7 +526,9 @@ def _vm(edata, curr_cands=None):
 borda_minimax_faceoff_properties = VotingMethodProperties(
     condorcet_winner=True,
     condorcet_loser=True,
-    pareto_dominance=True,)
+    pareto_dominance=True,
+    positive_involvement=False,
+    )
 @vm(name="Borda-Minimax Faceoff",
     properties=borda_minimax_faceoff_properties,
     input_types=[ElectionTypes.PROFILE])
@@ -524,4 +547,4 @@ def borda_minimax_faceoff(edata, curr_cands=None):
 
     """
 
-    return _faceoff(borda, minimax)(edata, curr_cands=curr_cands)
+    return _faceoff(borda, minimax)(edata, curr_cands=curr_cands)

pref_voting/helper.py

@@ -204,7 +204,7 @@ def weak_orders(A):
         yield {}
         return
     for k in range(1, len(A) + 1):
-        for B in itertools.combinations(A, k):
+        for B in combinations(A, k):
             for order in weak_orders(set(A) - set(B)):
                 new_order = {cand: rank + 1 for cand, rank in order.items()}
                 yield {**new_order, **{cand: 0 for cand in B}}