86 lines
2.9 KiB
Python
86 lines
2.9 KiB
Python
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# pyRCV2: Preferential vote counting
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# Copyright © 2020–2021 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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from pytest_steps import test_steps
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import pyRCV2.blt
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import pyRCV2.numbers
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from pyRCV2.method.meek import MeekSTVCounter
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from pyRCV2.model import CandidateState
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import tests.util
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import csv
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def isclose(a, b):
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# Allow discrepancy of ~0.01
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diff = a - b
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if diff < pyRCV2.numbers.Num('0.014') and diff > pyRCV2.numbers.Num('-0.014'):
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return True
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return False
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# Read model CSV
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with open('tests/data/ers97_meekm.csv', 'r', newline='') as f:
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reader = csv.reader(f)
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data = [x for x in reader]
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candidates = [data[i][0] for i in range(2, len(data) - 2)]
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@test_steps(*['Stage {}'.format(data[0][i]) for i in range(1, len(data[0]), 2)])
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def test_ers97_meekm_py():
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"""Compare count of ers97.blt with model result produced by Hill et al. reference implementation"""
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pyRCV2.numbers.set_numclass(pyRCV2.numbers.FixedGuarded)
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pyRCV2.numbers.set_dps(4)
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with open('tests/data/ers97.blt', 'r') as f:
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election = pyRCV2.blt.readBLT(f.read())
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assert len(election.candidates) == len(candidates)
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counter = MeekSTVCounter(election, {
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'quota': 'droop_exact',
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'quota_criterion': 'gt',
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'quota_mode': 'progressive',
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'ties': []
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})
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result = counter.reset()
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for i in range(1, len(data[0]), 2):
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stage = int(data[0][i])
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while len(counter.step_results) < stage:
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result = counter.step()
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comment = data[1][i]
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assert result.comment == comment, 'Failed to verify comment'
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for j, cand in enumerate(candidates):
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votes = pyRCV2.numbers.Num(data[j + 2][i])
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cc = next(cc for c, cc in result.candidates.items() if c.name == cand)
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assert isclose(cc.votes, votes), 'Failed to verify candidate "{}" votes, got {} expected {}'.format(cand, cc.votes.pp(2), votes.pp(2))
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state = data[j + 2][i + 1] if len(data[j + 2]) > (i + 1) else ''
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accept = {'': CandidateState.HOPEFUL, 'EL': CandidateState.ELECTED, 'EX': CandidateState.EXCLUDED}
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assert cc.state == accept[state], 'Failed to verify candidate "{}" state'.format(cand)
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# NB: Ignore exhausted votes
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quota = pyRCV2.numbers.Num(data[len(candidates) + 3][i])
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assert isclose(result.quota, quota), 'Failed to verify quota, got {} expected {}'.format(result.quota.pp(2), quota.pp(2))
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yield 'Stage {}'.format(stage)
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