def section_find_winner(section):
win_threshold = Voter.count_eligible() * section.majority_for_change
first_votes = {}
for c in section.change_set.all():
first_votes[c] = Vote.do_count(section.id, c.id, 1)
while True:
lowest_count, lowest_c = None, None
tuple_list = list(first_votes.items())
tuple_list.sort(key=lambda x: x[1])
highest_count = tuple_list[len(tuple_list)-1][1]
if highest_count >= win_threshold:
top = [t[0] for t in tuple_list if t[1] == highest_count]
return section_tie_break(section, top)
lowest_count = tuple_list[0][1]
elim_cands = [t[0] for t in tuple_list if t[1] == lowest_count]
lowest_c, _ = section_tie_break(section, elim_cands, find_worst=True)
# re-assign votes for lowest_c to next pref - TODO: optimize!
for orig_vote in Vote.objects.filter(section=section, change=lowest_c):
alternates = Vote.objects.filter(voter=orig_vote.voter, section=section, priority__gt=orig_vote.priority)
if len(alternates) > 0:
alt = alternates[0].change
if alt not in first_votes:
first_votes[alt] = 0
first_votes[alt] += 1
# eliminate lowest_c
del first_votes[lowest_c]
if len(first_votes) == 0:
return (None, None)
def section_tie_break(section, change_list, find_worst=False):
if len(change_list) == 0:
raise Exception('av tie break given empty change_list')
#print('section tie break: ' + ' '.join([c.name for c in change_list]))
change_tuples = []
for change in change_list:
prefs = Vote.do_count(section.id, change.id)
change_tuples.append((change, prefs))
#print('section tie break: ' + str(change_tuples))
return tie_break(change_tuples, find_worst)
