110 lines
4.5 KiB
Python
110 lines
4.5 KiB
Python
# pyRCV2: Preferential vote counting
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# Copyright © 2020 Lee Yingtong Li (RunasSudo)
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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import pyRCV2.blt
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import pyRCV2.model
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import pyRCV2.numbers
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from pyRCV2.method.base_stv import BaseUIGSTVCounter, BaseWIGSTVCounter
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from pyRCV2.method.wright import WrightSTVCounter
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from pyRCV2.ties import TiesBackwards, TiesPrompt, TiesRandom
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def add_parser(subparsers):
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parser = subparsers.add_parser('stv', help='single transferable vote')
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parser.add_argument('file', help='path to BLT file')
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parser.add_argument('--quota', '-q', choices=['droop', 'droop_exact', 'hare', 'hare_exact'], default='droop', help='quota calculation (default: droop)')
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parser.add_argument('--quota-criterion', '-c', choices=['geq', 'gt'], default='geq', help='quota criterion (default: geq)')
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parser.add_argument('--prog-quota', action='store_true', help='progressively reducing quota')
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parser.add_argument('--numbers', '-n', choices=['fixed', 'rational', 'int', 'native'], default='fixed', help='numbers mode (default: fixed)')
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parser.add_argument('--decimals', type=int, default=5, help='decimal places if --numbers fixed (default: 5)')
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parser.add_argument('--surplus-order', '-s', choices=['size', 'order'], default='size', help='whether to distribute surpluses by size or by order of election (default: size)')
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parser.add_argument('--method', '-m', choices=['wig', 'uig', 'wright'], default='wig', help='method of surpluses and exclusions (default: wig - weighted inclusive Gregory)')
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parser.add_argument('--ties', '-t', action='append', choices=['backwards', 'prompt', 'random'], default=None, help='how to resolve ties (default: backwards then random)')
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def print_step(result):
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print(result.comment)
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for candidate, count_card in result.candidates.items():
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state = None
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if count_card.state == pyRCV2.model.CandidateState.ELECTED or count_card.state == pyRCV2.model.CandidateState.PROVISIONALLY_ELECTED:
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state = 'ELECTED'
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elif count_card.state == pyRCV2.model.CandidateState.EXCLUDED:
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state = 'Excluded'
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elif count_card.state == pyRCV2.model.CandidateState.WITHDRAWN:
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state = 'Withdrawn'
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if state is None:
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print('- {}: {} ({})'.format(candidate.name, count_card.votes.pp(2), count_card.transfers.pp(2)))
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else:
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print('- {}: {} ({}) - {}'.format(candidate.name, count_card.votes.pp(2), count_card.transfers.pp(2), state))
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print('Exhausted: {} ({})'.format(result.exhausted.votes.pp(2), result.exhausted.transfers.pp(2)))
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print('Loss to fraction: {} ({})'.format(result.loss_fraction.votes.pp(2), result.loss_fraction.transfers.pp(2)))
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print('Total votes: {}'.format(result.total.pp(2)))
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print('Quota: {}'.format(result.quota.pp(2)))
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print()
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def main(args):
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# Set settings
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if args.numbers == 'native':
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pyRCV2.numbers.set_numclass(pyRCV2.numbers.Native)
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elif args.numbers == 'int':
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pyRCV2.numbers.set_numclass(pyRCV2.numbers.NativeInt)
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elif args.numbers == 'rational':
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pyRCV2.numbers.set_numclass(pyRCV2.numbers.Rational)
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elif args.numbers == 'fixed':
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pyRCV2.numbers.set_numclass(pyRCV2.numbers.Fixed)
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pyRCV2.numbers.set_dps(args.decimals)
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with open(args.file, 'r') as f:
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election = pyRCV2.blt.readBLT(f.read())
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# Create counter
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if args.method == 'uig':
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counter = BaseUIGSTVCounter(election, vars(args))
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elif args.method == 'wright':
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counter = WrightSTVCounter(election, vars(args))
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else:
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counter = BaseWIGSTVCounter(election, vars(args))
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if args.ties is None:
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args.ties = ['backwards', 'random']
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counter.options['ties'] = []
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for t in args.ties:
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if t == 'backwards':
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counter.options['ties'].append(TiesBackwards())
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elif t == 'prompt':
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counter.options['ties'].append(TiesPrompt())
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elif t == 'random':
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counter.options['ties'].append(TiesRandom())
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# Reset
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result = counter.reset()
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print_step(result)
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# Step election
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while True:
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result = counter.step()
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if isinstance(result, pyRCV2.model.CountCompleted):
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break
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print_step(result)
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