152 lines
4.3 KiB
Python
152 lines
4.3 KiB
Python
# 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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__pragma__ = lambda x: None
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is_py = False
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__pragma__('skip')
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is_py = True
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__pragma__('noskip')
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from pyRCV2.random import SHARandom
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class RequireInput(Exception): # pragma: no cover
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# For JS only
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# Exceptions for control flow? In my code? It's more likely thank you think!
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def __init__(self, message):
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self.message = message
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class TiesPrompt:
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"""Prompt the user to break ties"""
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def __init__(self):
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self.buffer = None
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def choose_lowest(self, l):
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if is_py:
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print('Multiple tied candidates:')
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for i, x in enumerate(l):
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print('{}. {}'.format(i + 1, x[0].name))
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while True:
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choice = input('Which candidate to select? ')
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try:
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choice = int(choice)
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if choice >= 1 and choice < len(l) + 1:
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break
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except ValueError:
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pass
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print()
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return l[i - 1]
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else: # pragma: no cover
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if self.buffer is not None:
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try:
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choice = int(self.buffer)
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if choice >= 1 and choice < len(l) + 1:
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self.buffer = None
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return l[choice - 1]
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except ValueError:
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self.buffer = None
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pass
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self.buffer = None
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# Require prompting
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message = 'Multiple tied candidates:\n'
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for i, x in enumerate(l):
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message += (i + 1) + '. ' + x[0].name + '\n'
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message += 'Which candidate to select?'
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raise RequireInput(message)
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def choose_highest(self, l):
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return self.choose_lowest(l)
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class TiesBackwards:
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"""
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Break ties based on the candidate who had the highest/lowest total at the end
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of the most recent stage where one candidate had a higher/lower total than
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all other tied candidates, if such a stage exists
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"""
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def __init__(self, counter):
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self.counter = counter
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def choose_lowest(self, l):
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for result in reversed(self.counter.step_results):
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__pragma__('opov')
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l2 = [(x, result.candidates[x[0]].votes) for x in l]
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l2.sort(key=lambda x: x[1])
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if l2[0][1] < l2[1][1]: # Did one candidate have fewer votes than the others?
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return l2[0][0]
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__pragma__('noopov')
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return None
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def choose_highest(self, l):
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for result in reversed(self.counter.step_results):
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__pragma__('opov')
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l2 = [(x, result.candidates[x[0]].votes) for x in l]
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l2.sort(key=lambda x: x[1], reverse=True)
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if l2[0][1] > l2[1][1]: # Did one candidate have more votes than the others?
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return l2[0][0]
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__pragma__('noopov')
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return None
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class TiesForwards:
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"""
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Break ties based on the candidate who had the highest/lowest total at the end
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of the earliest stage where one candidate had a higher/lower total than
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all other tied candidates, if such a stage exists
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"""
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def __init__(self, counter):
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self.counter = counter
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def choose_lowest(self, l):
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for result in self.counter.step_results:
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__pragma__('opov')
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l2 = [(x, result.candidates[x[0]].votes) for x in l]
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l2.sort(key=lambda x: x[1])
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if l2[0][1] < l2[1][1]: # Did one candidate have fewer votes than the others?
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return l2[0][0]
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__pragma__('noopov')
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return None
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def choose_highest(self, l):
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for result in self.counter.step_results:
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__pragma__('opov')
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l2 = [(x, result.candidates[x[0]].votes) for x in l]
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l2.sort(key=lambda x: x[1], reverse=True)
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if l2[0][1] > l2[1][1]: # Did one candidate have more votes than the others?
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return l2[0][0]
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__pragma__('noopov')
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return None
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class TiesRandom:
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"""Break ties randomly, using the SHARandom deterministic RNG"""
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def __init__(self, seed):
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self.random = SHARandom(seed)
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def choose_lowest(self, l):
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l.sort(key=lambda x: x[0].name)
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return l[self.random.next(len(l))]
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def choose_highest(self, l):
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l.sort(key=lambda x: x[0].name)
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return l[self.random.next(len(l))]
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