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pyRCV2/tests/test_prsa.py

221 lines
8.7 KiB
Python

# pyRCV2: Preferential vote counting
# Copyright © 2020 Lee Yingtong Li (RunasSudo)
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import pyRCV2.blt
import pyRCV2.numbers
from pyRCV2.method.base_stv import EGSTVCounter
from pyRCV2.model import CandidateState, CountCompleted
def isclose(x, y):
# There will be some discrepancy due to how the PRSA count rounds transfer values, so accept up to 0.1 votes difference
return abs(int(x.impl) - y) < 100
def test_prsa1():
"""Compare count of prsa1.blt with model result at http://www.prsa.org.au/example1.pdf"""
pyRCV2.numbers.set_numclass(pyRCV2.numbers.Fixed)
pyRCV2.numbers.set_dps(5)
with open('tests/data/prsa1.blt', 'r') as f:
election = pyRCV2.blt.readBLT(f.read())
assert len(election.candidates) == 7
c_evans = next(c for c in election.candidates if c.name == 'Evans')
c_grey = next(c for c in election.candidates if c.name == 'Grey')
c_thomson = next(c for c in election.candidates if c.name == 'Thomson')
c_ames = next(c for c in election.candidates if c.name == 'Ames')
c_reid = next(c for c in election.candidates if c.name == 'Reid')
c_spears = next(c for c in election.candidates if c.name == 'Spears')
c_white = next(c for c in election.candidates if c.name == 'White')
counter = EGSTVCounter(election, {
'surplus_order': 'order',
'papers': 'transferable',
'exclusion': 'parcels_by_order'
})
# Stage 1
result = counter.reset()
assert len(result.candidates.impl) == 7
assert int(result.total.impl) == 65000
assert int(result.quota.impl) == 13001
assert result.comment == 'First preferences'
assert isclose(result.candidates[c_evans].votes, 1000)
assert isclose(result.candidates[c_grey].votes, 34000)
assert isclose(result.candidates[c_thomson].votes, 5000)
assert isclose(result.candidates[c_ames].votes, 10000)
assert isclose(result.candidates[c_reid].votes, 1000)
assert isclose(result.candidates[c_spears].votes, 11000)
assert isclose(result.candidates[c_white].votes, 3000)
assert isclose(result.exhausted.votes, 0)
# Stage 2
result = counter.step()
assert result.comment == 'Surplus of Grey'
assert isclose(result.candidates[c_evans].votes, 2234)
assert isclose(result.candidates[c_grey].votes, 13001)
assert isclose(result.candidates[c_thomson].votes, 7468)
assert isclose(result.candidates[c_ames].votes, 18638)
assert isclose(result.candidates[c_reid].votes, 1617)
assert isclose(result.candidates[c_spears].votes, 17170)
assert isclose(result.candidates[c_white].votes, 4851)
assert isclose(result.exhausted.votes, 0)
# Stage 3
result = counter.step()
assert result.comment == 'Surplus of Ames'
assert isclose(result.candidates[c_evans].votes, 3038)
assert isclose(result.candidates[c_grey].votes, 13001)
assert isclose(result.candidates[c_thomson].votes, 8674)
assert isclose(result.candidates[c_ames].votes, 13001)
assert isclose(result.candidates[c_reid].votes, 2019)
assert isclose(result.candidates[c_spears].votes, 17170)
assert isclose(result.candidates[c_white].votes, 8067)
assert isclose(result.exhausted.votes, 0)
# Stage 4
result = counter.step()
assert result.comment == 'Surplus of Spears'
assert isclose(result.candidates[c_evans].votes, 4823)
assert isclose(result.candidates[c_grey].votes, 13001)
assert isclose(result.candidates[c_thomson].votes, 8674)
assert isclose(result.candidates[c_ames].votes, 13001)
assert isclose(result.candidates[c_reid].votes, 3804)
assert isclose(result.candidates[c_spears].votes, 13001)
assert isclose(result.candidates[c_white].votes, 8662)
assert isclose(result.exhausted.votes, 0)
# Stage 5
result = counter.step()
assert result.comment == 'Exclusion of Reid'
assert isclose(result.candidates[c_reid].transfers, -1000)
assert isclose(result.candidates[c_white].transfers, 1000)
# Stage 6
result = counter.step()
assert result.comment == 'Exclusion of Reid'
assert isclose(result.candidates[c_reid].transfers, -617)
assert isclose(result.candidates[c_white].transfers, 617)
# Stage 7
result = counter.step()
assert result.comment == 'Exclusion of Reid'
assert isclose(result.candidates[c_reid].transfers, -402)
assert isclose(result.candidates[c_evans].transfers, 402)
# Stage 8
result = counter.step()
assert result.comment == 'Exclusion of Reid'
assert isclose(result.candidates[c_reid].transfers, -1785)
assert isclose(result.candidates[c_evans].transfers, 595)
assert isclose(result.candidates[c_thomson].transfers, 1190)
assert isclose(result.candidates[c_evans].votes, 5820)
assert isclose(result.candidates[c_grey].votes, 13001)
assert isclose(result.candidates[c_thomson].votes, 9864)
assert isclose(result.candidates[c_ames].votes, 13001)
assert isclose(result.candidates[c_reid].votes, 0)
assert isclose(result.candidates[c_spears].votes, 13001)
assert isclose(result.candidates[c_white].votes, 10279)
assert isclose(result.exhausted.votes, 0)
# Stage 9
result = counter.step()
assert result.comment == 'Exclusion of Evans'
assert isclose(result.candidates[c_evans].transfers, -1000)
assert isclose(result.candidates[c_thomson].transfers, 1000)
# Stage 10
result = counter.step()
assert result.comment == 'Exclusion of Evans'
assert isclose(result.candidates[c_evans].transfers, -1234)
assert isclose(result.exhausted.transfers, 1234)
# Stage 11
result = counter.step()
assert result.comment == 'Exclusion of Evans'
assert isclose(result.candidates[c_evans].transfers, -804)
assert isclose(result.candidates[c_thomson].transfers, 402)
assert isclose(result.candidates[c_white].transfers, 402)
# Stage 12
result = counter.step()
assert result.comment == 'Exclusion of Evans'
assert isclose(result.candidates[c_evans].transfers, -1785)
assert isclose(result.candidates[c_white].transfers, 1190)
assert isclose(result.exhausted.transfers, 595)
# Stage 13
result = counter.step()
assert result.comment == 'Exclusion of Evans'
assert isclose(result.candidates[c_evans].transfers, -402)
assert isclose(result.candidates[c_thomson].transfers, 402)
# Stage 14
result = counter.step()
assert result.comment == 'Exclusion of Evans'
assert isclose(result.candidates[c_evans].transfers, -595)
assert isclose(result.candidates[c_white].transfers, 595)
assert isclose(result.candidates[c_evans].votes, 0)
assert isclose(result.candidates[c_grey].votes, 13001)
assert isclose(result.candidates[c_thomson].votes, 11668)
assert isclose(result.candidates[c_ames].votes, 13001)
assert isclose(result.candidates[c_reid].votes, 0)
assert isclose(result.candidates[c_spears].votes, 13001)
assert isclose(result.candidates[c_white].votes, 12466)
assert isclose(result.exhausted.votes, 1829)
# Stage 15
result = counter.step()
assert result.comment == 'Exclusion of Thomson'
assert isclose(result.candidates[c_thomson].transfers, -5000)
assert isclose(result.exhausted.transfers, 5000)
# Stage 16
result = counter.step()
assert result.comment == 'Exclusion of Thomson'
assert isclose(result.candidates[c_thomson].transfers, -2468)
assert isclose(result.exhausted.transfers, 2468)
# Stage 17
result = counter.step()
assert result.comment == 'Exclusion of Thomson'
assert isclose(result.candidates[c_thomson].transfers, -1206)
assert isclose(result.candidates[c_white].transfers, 1206)
assert isclose(result.candidates[c_evans].votes, 0)
assert isclose(result.candidates[c_grey].votes, 13001)
assert isclose(result.candidates[c_thomson].votes, 2994)
assert isclose(result.candidates[c_ames].votes, 13001)
assert isclose(result.candidates[c_reid].votes, 0)
assert isclose(result.candidates[c_spears].votes, 13001)
assert isclose(result.candidates[c_white].votes, 13672)
assert isclose(result.exhausted.votes, 9297)
assert result.candidates[c_evans].state == CandidateState.EXCLUDED
assert result.candidates[c_grey].state == CandidateState.ELECTED
assert result.candidates[c_thomson].state == CandidateState.EXCLUDING
assert result.candidates[c_ames].state == CandidateState.ELECTED
assert result.candidates[c_reid].state == CandidateState.EXCLUDED
assert result.candidates[c_spears].state == CandidateState.ELECTED
assert result.candidates[c_white].state == CandidateState.PROVISIONALLY_ELECTED
# Count complete
result = counter.step()
assert isinstance(result, CountCompleted)