Implement Wright STV

This commit is contained in:
RunasSudo 2020-10-18 21:47:59 +11:00
parent 631fa432c6
commit f8ee464421
Signed by: RunasSudo
GPG Key ID: 7234E476BF21C61A
6 changed files with 90 additions and 11 deletions

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@ -40,6 +40,7 @@
<option value="scottish" selected>Scottish STV</option> <option value="scottish" selected>Scottish STV</option>
<option value="stvc">pyRCV STV-C</option> <option value="stvc">pyRCV STV-C</option>
<option value="senate">Australian Senate STV</option> <option value="senate">Australian Senate STV</option>
<option value="wright">Wright STV</option>
</select> </select>
</label> </label>
<button id="btnAdvancedOptions" onclick="clickAdvancedOptions()">Show advanced options</button> <button id="btnAdvancedOptions" onclick="clickAdvancedOptions()">Show advanced options</button>
@ -92,10 +93,11 @@
</select> </select>
</label> </label>
<label> <label>
Transfer value: Method:
<select id="selTransfers"> <select id="selTransfers">
<option value="wig" selected>Weighted inclusive Gregory</option> <option value="wig" selected>Weighted inclusive Gregory</option>
<option value="uig">Unweighted inclusive Gregory</option> <option value="uig">Unweighted inclusive Gregory</option>
<option value="wright">Wright STV</option>
</select> </select>
</label> </label>
<br> <br>

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@ -50,11 +50,21 @@ function changePreset() {
document.getElementById('selQuotaCriterion').value = 'geq'; document.getElementById('selQuotaCriterion').value = 'geq';
document.getElementById('selQuota').value = 'droop'; document.getElementById('selQuota').value = 'droop';
document.getElementById('chkProgQuota').checked = false; document.getElementById('chkProgQuota').checked = false;
document.getElementById('chkBulkExclusion').checked = false; document.getElementById('chkBulkExclusion').checked = true;
document.getElementById('selNumbers').value = 'int'; document.getElementById('selNumbers').value = 'int';
document.getElementById('selSurplus').value = 'order'; document.getElementById('selSurplus').value = 'order';
document.getElementById('selTransfers').value = 'uig'; document.getElementById('selTransfers').value = 'uig';
document.getElementById('selTies').value = 'backwards_random'; document.getElementById('selTies').value = 'backwards_random';
} else if (document.getElementById('selPreset').value === 'wright') {
document.getElementById('selQuotaCriterion').value = 'geq';
document.getElementById('selQuota').value = 'droop';
document.getElementById('chkProgQuota').checked = false;
document.getElementById('chkBulkExclusion').checked = true;
document.getElementById('selNumbers').value = 'fixed';
document.getElementById('txtDP').value = '5';
document.getElementById('selSurplus').value = 'size';
document.getElementById('selTransfers').value = 'wright';
document.getElementById('selTies').value = 'backwards_random';
} }
} }

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@ -41,10 +41,12 @@ onmessage = function(evt) {
// Create counter // Create counter
let counter; let counter;
if (evt.data.transfers === 'wig') { if (evt.data.transfers === 'uig') {
counter = py.pyRCV2.method.base_stv.BaseWIGSTVCounter(election, evt.data.options);
} else {
counter = py.pyRCV2.method.base_stv.BaseUIGSTVCounter(election, evt.data.options); counter = py.pyRCV2.method.base_stv.BaseUIGSTVCounter(election, evt.data.options);
} else if (evt.data.transfers === 'wright') {
counter = py.pyRCV2.method.wright.WrightSTVCounter(election, evt.data.options);
} else {
counter = py.pyRCV2.method.base_stv.BaseWIGSTVCounter(election, evt.data.options);
} }
// Reset // Reset

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@ -192,11 +192,7 @@ class BaseSTVCounter:
Exclude the lowest ranked hopeful Exclude the lowest ranked hopeful
""" """
hopefuls = [(c, cc) for c, cc in self.candidates.items() if cc.state == CandidateState.HOPEFUL] candidate_excluded, count_card = self.candidate_to_exclude()
hopefuls.sort(lambda x: x[1].votes)
# TODO: Handle ties
candidate_excluded, count_card = hopefuls[0]
count_card.state = CandidateState.EXCLUDED count_card.state = CandidateState.EXCLUDED
# Exclude this candidate # Exclude this candidate
@ -221,6 +217,19 @@ class BaseSTVCounter:
) )
__pragma__('noopov') __pragma__('noopov')
def candidate_to_exclude(self):
"""
Determine the candidate to exclude
"""
hopefuls = [(c, cc) for c, cc in self.candidates.items() if cc.state == CandidateState.HOPEFUL]
hopefuls.sort(lambda x: x[1].votes)
# TODO: Handle ties
candidate_excluded, count_card = hopefuls[0]
return candidate_excluded, count_card
def do_exclusion(self, candidate_excluded, count_card): def do_exclusion(self, candidate_excluded, count_card):
""" """
Exclude the given candidate and transfer the votes Exclude the given candidate and transfer the votes

56
pyRCV2/method/wright.py Normal file
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@ -0,0 +1,56 @@
# 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/>.
from pyRCV2.method.base_stv import BaseWIGSTVCounter
from pyRCV2.model import CandidateState, CountCard
from pyRCV2.safedict import SafeDict
class WrightSTVCounter(BaseWIGSTVCounter):
"""
Wright STV implementation
"""
def exclude_candidate(self):
"""
Overrides BaseSTVCounter.exclude_candidate per Wright STV
"""
candidate_excluded, count_card = self.candidate_to_exclude()
count_card.state = CandidateState.EXCLUDED
# Reset the count
new_candidates = SafeDict()
for candidate, count_card in self.candidates.items():
new_count_card = CountCard()
if count_card.state == CandidateState.WITHDRAWN:
new_count_card.state = CandidateState.WITHDRAWN
elif count_card.state == CandidateState.EXCLUDED:
new_count_card.state = CandidateState.EXCLUDED
__pragma__('opov')
new_candidates[candidate] = new_count_card
__pragma__('noopov')
self.candidates = new_candidates
self.exhausted = CountCard()
self.loss_fraction = CountCard()
self.num_elected = 0
result = self.reset()
result.comment = 'Exclusion of ' + candidate_excluded.name
return result

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@ -16,7 +16,7 @@
import pyRCV2.blt import pyRCV2.blt
import pyRCV2.model import pyRCV2.model
import pyRCV2.method, pyRCV2.method.base_stv import pyRCV2.method, pyRCV2.method.base_stv, pyRCV2.method.wright
import pyRCV2.numbers import pyRCV2.numbers
__pragma__('js', '{}', 'export {pyRCV2, isinstance, repr, str};') __pragma__('js', '{}', 'export {pyRCV2, isinstance, repr, str};')