def test_ranked_bury():
v = spatial.Voters(seed=0)
v.add(voter_pref)
c = spatial.Candidates(v)
c.add(candidate_pref)
strategy = {
'tactics': 'bury',
'subset': '',
'ratio': 1,
'underdog': None,
'frontrunnertype': 'eliminate'
}
s2 = spatial.Strategies(v).add(**strategy)
e2 = spatial.Election(voters=v, candidates=c, strategies=s2)
e2.run('ranked_pairs')
right = [[1, 2, 0], [1, 2, 0], [1, 2, 0], [1, 2, 0], [1, 2, 0], [1, 2, 0],
[1, 2, 0], [0, 1, 0], [0, 1, 0], [0, 1, 0], [0, 0, 1], [0, 0, 1],
[0, 0, 1], [0, 0, 1], [0, 0, 1]]
right = votesim.votemethods.tools.rcv_reorder(right)
ballots = e2.result.ballots
ballots = votesim.votemethods.tools.rcv_reorder(ballots)
assert np.all(right == ballots)
return
def test_ranked_deep_bury():
"""Test ranked burial tactic.
Burial strategies
--------------------------
* For #0 voters, their ballots are unchanged as their least favorite is
already buried.
* For #1 voters, they decide to bury #2.
* For #2 voters, they decide to bury #1.
Outcomes
--------
Burial strategies backfires with #1 and #2 voters, allowing #0 to win.
"""
v = spatial.Voters(seed=0)
v.add(voter_pref)
c = spatial.Candidates(v)
c.add(candidate_pref)
# run honest election
e1 = spatial.Election(voters=v, candidates=c)
result1 = e1.run('ranked_pairs')
# Make sure condorcet winner was found
assert 1 in e1.result.winners
#run strategic election
strategy = {
'tactics': 'deep_bury',
'ratio': 1,
'underdog': None,
'subset': '',
'frontrunnertype': 'eliminate'
}
s2 = spatial.Strategies(v).add(**strategy)
e2 = spatial.Election(voters=v, candidates=c, strategies=s2)
e2.run('ranked_pairs', result=result1)
# Make sure the correct front runners were
tballots = e2.ballotgen.tacticalballots
tgroup = list(tballots.root._tactical_groups.values())[0]
front_runners = tgroup.front_runners
assert 1 in front_runners
assert 2 in front_runners
# Check that #0 is the winner
assert 0 in e2.result.winners
ballots = e2.result.ballots
ballots = votesim.votemethods.tools.rcv_reorder(ballots)
# Check the new tactical rankings
right = [[1, 2, 0], [1, 2, 0], [1, 2, 0], [1, 2, 0], [1, 2, 0], [1, 2, 0],
[1, 2, 0], [3, 1, 0], [3, 1, 0], [3, 1, 0], [3, 0, 1], [3, 0, 1],
[3, 0, 1], [3, 0, 1], [3, 0, 1]]
right = votesim.votemethods.tools.rcv_reorder(right)
assert np.all(right == ballots)
return
def test_plurality_chain():
"""Test re-using honest election data to initialize
strategic runs."""
pref = [-1]*7 + [-0.5]*2 + [0.5]*3 + [1]*5
pref = np.array(pref)[:, None]
v = spatial.Voters(seed=0)
v.add(pref)
# Generate candidate preferences
cpref = [-1, -.5, .5, 1]
cpref = np.array(cpref)[:, None]
c = spatial.Candidates(v)
c.add(cpref)
# Run honest
e1 = spatial.Election(voters=v, candidates=c)
e1.run('plurality',)
tally1 = e1.result.runner.output['tally']
result1 = e1.result
assert np.all(tally1 == np.array([7, 2, 3, 5]))
# Run tactical
strategy = {'tactics' : 'bullet_preferred',
'ratio' : 1,
'underdog' : None,
'subset' : ''
}
s1 = spatial.Strategies(v).add(**strategy)
e1.set_models(strategies=s1)
e1.run('plurality', result=result1)
tally2 = e1.result.runner.output['tally']
assert np.all(tally2 == np.array([9, 0, 0, 8]))
# Run one sided
strategy = {'tactics' : 'bullet_preferred',
'ratio' : 1,
'underdog' : None,
'subset' : 'underdog'}
s1 = spatial.Strategies(v).add(**strategy)
e1.set_models(strategies=s1)
e1.run('plurality', result=result1)
tally3 = e1.result.runner.output['tally']
assert np.all(tally3 == np.array([7, 2, 0, 8]))
return locals()
def test_plurality_bullet_preferred():
"""Test plurality bullet voting strategy.
Scenario attributes:
- 3 candidate race with 3 concentrated, coincident voter groups
>>> Candidates #0 #1 #2
>>> Preference locations = [-1, 0.5, 1]
>>> Number of voters = [ 7, 3, 5]
- If voters are honest, plurality candidate #0 should win with 7 votes
- If voters are strategic and consider only the top two candidates,
Candidate #1 supporters also lean towards #2 - therefore
candidate #2 should win with 3 + 5 = 8 votes.
"""
pref = [-1]*7 + [0.5]*3 + [1]*5
pref = np.array(pref)[:, None]
v = spatial.Voters(seed=0)
v.add(pref)
cpref = [-1, .5, 1]
cpref = np.array(cpref)[:, None]
c = spatial.Candidates(v)
c.add(cpref)
#####################################################################
# Run honest election
e1 = spatial.Election(voters=v, candidates=c)
e1.run('plurality')
tally1 = e1.result.runner.output['tally']
result1 = e1.result
#####################################################################
# Run strategic election
strategy1 = {'tactics' : 'bullet_preferred',
'ratio' : 1,
'subset' : 'underdog',
'underdog' : None,}
s = spatial.Strategies(v)
s.add(**strategy1)
e1.set_models(strategies=s)
e1.run('plurality', result=result1)
tally2 = e1.result.runner.output['tally']
result2 = e1.result
# Check honest vote tally
assert np.all(tally1 == np.array([7, 3, 5]))
# Check strategic vote tally
assert np.all(tally2 == np.array([7, 0, 8]))
# Check honest winner
assert 0 in result1.winners
# Check strategic winner
assert 2 in result2.winners
return
def test_plurality_ratio():
"""Test adjusted the ratio of tactical to honest voters"""
v = spatial.Voters(seed=0)
v.add_random(100)
c = spatial.Candidates(voters=v, seed=1)
c.add_random(5)
e1 = spatial.Election(voters=v, candidates=c)
result1 = e1.run('plurality')
tally1 = e1.result.runner.output['tally']
print('---------------------------------------')
for tacti_num in [0, 10, 25, 50, 75, 100]:
ratio = tacti_num / 100.
strategy = {'tactics' : 'bullet_preferred',
'ratio' : ratio,
'underdog' : None,
'subset' : ''}
s1 = spatial.Strategies(v).add(**strategy)
e1.set_models(strategies=s1)
e1.run('plurality', result=result1)
tally2 = e1.result.runner.output['tally']
print('vote tally =', tally2)
bgen = e1.ballotgen
tactical_ballots = bgen.tacticalballots
num_tactical_voters = len(tactical_ballots.group_index['tactical-0'])
# check that tactical voters number is correct
assert num_tactical_voters == tacti_num
# check that total voters in group index is correct.
group_index = tactical_ballots.group_index
count1 = len(group_index['honest-0'])
count2 = len(group_index['tactical-0'])
assert count1 + count2 == 100
count3 = len(group_index['topdog-0'])
count4 = len(group_index['underdog-0'])
assert count3 + count4 == count2
return
def test_ranked_deep_bury_onesided():
"""Test one sided burial strategy.
For one-sided, only the under-dog voters vote tactically.
* Honest Condorcet winner is Candidate #1.
* Runner up is Candidate #2.
* Therefore only #2 voters vote strategically in this scenario.
Outcomes
-------
It seems like burial backfires again in this scenario.
"""
v = spatial.Voters(seed=0)
v.add(voter_pref)
c = spatial.Candidates(v)
c.add(candidate_pref)
strategy = {
'tactics': 'deep_bury',
'subset': 'underdog',
'ratio': 1,
'underdog': None,
'frontrunnertype': 'eliminate'
}
s2 = spatial.Strategies(v).add(**strategy)
e2 = spatial.Election(voters=v, candidates=c, strategies=s2)
e2.run('ranked_pairs')
right = [[1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3],
[1, 2, 3], [3, 1, 2], [3, 1, 2], [3, 1, 2], [3, 0, 1], [3, 0, 1],
[3, 0, 1], [3, 0, 1], [3, 0, 1]]
right = votesim.votemethods.tools.rcv_reorder(right)
ballots = e2.result.ballots
ballots = votesim.votemethods.tools.rcv_reorder(ballots)
assert np.all(right == ballots)
return
def test_plurality_onesided():
"""Test plurality one sided voting strategy.
- #0 would win if #1 voters are strategic.
- #3 will win if #1 are honest and #2 voters use one-sided strategy.
>>> Candidates #0 #1 #2 #3
>>> Preference locations = [-1, -0.5, 0.5, 1]
>>> Number of voters = [ 7, 2, 3, 5]
"""
# Generate voter preferences
pref = [-1]*7 + [-0.5]*2 + [0.5]*3 + [1]*5
pref = np.array(pref)[:, None]
v = spatial.Voters(seed=0)
v.add(pref)
# Generate candidate preferences
cpref = [-1, -.5, .5, 1]
cpref = np.array(cpref)[:, None]
c = spatial.Candidates(v)
c.add(cpref)
#####################################################################
# Run honest election
e1 = spatial.Election(voters=v, candidates=c)
e1.run('plurality')
tally1 = e1.result.runner.output['tally']
result1 = e1.result
assert np.all(tally1 == np.array([7, 2, 3, 5]))
assert 0 in e1.result.winners
#####################################################################
# Run one-sided tactical election
strategy1 = {'tactics' : 'bullet_preferred',
'ratio' : 1,
'subset' : 'underdog',
'underdog' : None,}
strat1 = spatial.Strategies(v).add(**strategy1)
e2 = spatial.Election(voters=v, candidates=c, strategies=strat1)
result2 = e2.run('plurality', result=result1)
tally2 = result2.runner.output['tally']
assert np.all(tally2 == np.array([7, 2, 0, 8]))
assert 3 in result2.winners
# Test metric comparison system.
tc = TacticCompare(e_strat=result2.stats,
e_honest=result1.stats,
)
# e2.electionStats.add_output(tc)
stats2 = result2.stats
stats1 = result1.stats
print('---------------------------------------')
print('one-sided regret change =', tc.regret)
print('')
print('one-sided VSE change = ', tc.regret_efficiency_candidate)
print('')
print('VSE tactical = ', stats2.winner.regret_efficiency_candidate)
print('VSE honest = ', stats1.winner.regret_efficiency_candidate)
#####################################################################
# Run full tactical election
strategy1 = {'tactics' : 'bullet_preferred',
'ratio' : 1,
'underdog' : None,
'subset' : ''}
strat1 = spatial.Strategies(v).add(**strategy1)
e3 = spatial.Election(voters=v, candidates=c, strategies=strat1)
result3 = e3.run('plurality', result=result1)
tally3 = result3.runner.output['tally']
assert np.all(tally3 == np.array([9, 0, 0, 8]))
assert 0 in result3.winners
# Test metric comparison system.
tc = TacticCompare(e_strat=result3.stats,
e_honest=result1.stats,
)
print('')
print('two-sided regret change =', tc.regret)
print('two-sided VSE change = ', tc.regret_efficiency_candidate)
docs = result3.output_docs
# Try to append new output to election results
e3.append_stat(tc)
df = e3.dataframe()
# pdb.set_trace()
return df
def tactical_model_v2(
name: str,
methods: list,
seed=0,
numvoters=51,
cnum=5,
cstd=1.5,
ndim=1,
tol=None,
ratio=1.0,
) -> spatial.Election:
"""Tactical Election model that test every single candidate as an underdog,
and tests topdog resistance using bullet voting.
"""
e = spatial.Election(None, None, seed=seed, name=name)
# Construct base strategy
strategy_base = {}
strategy_base['ratio'] = ratio
strategy_base['subset'] = 'underdog'
# Create underdog strategy
strategy2 = strategy_base.copy()
# Create topdog strategy
strategy3 = strategy_base.copy()
strategy3['tactics'] = ['bullet_preferred']
strategy3['subset'] = 'topdog'
# Generate voters
v = spatial.Voters(seed=seed, tol=tol, base='linear')
v.add_random(numvoters, ndim=ndim)
# Generate candidates
c = spatial.Candidates(v, seed=seed)
c.add_random(cnum, sdev=cstd)
e.set_models(voters=v, candidates=c)
# Construct election identification
eid = (
seed,
numvoters,
cnum,
ndim,
)
for method in methods:
# Set empty (honest) strategy
e.set_models(strategies=spatial.StrategiesEmpty())
e.user_data(eid=eid, strategy='honest')
result1 = e.run(etype=method)
winner = result1.winners[0]
stats_honest = result1.stats
underdog_list = list(range(cnum))
underdog_list.remove(winner)
# test each underdog
for underdog in underdog_list:
strategy2['underdog'] = underdog
strategy3['underdog'] = underdog
# test each tactic
tactics = get_tactics(method)
for tactic in tactics:
strategy2['tactics'] = tactic
# Run one-sided strategy
s = spatial.Strategies(v).add(**strategy2)
e.set_models(strategies=s)
e.user_data(eid=eid, strategy='one-sided')
result2 = e.run(etype=method, result=result1)
# Create tactical comparison output, add to output
tactic_compare = TacticCompare(e_strat=result2.stats,
e_honest=stats_honest)
e.append_stat(tactic_compare)
# Run two-sided strategy with top-dog bullet vote.
s.add(**strategy3)
e.set_models(strategies=s)
e.user_data(eid=eid, strategy='two-sided')
result3 = e.run(etype=method, result=result1)
# Create tactical comparison output, add to output
tactic_compare = TacticCompare(e_strat=result3.stats,
e_honest=stats_honest)
e.append_stat(tactic_compare)
return e
def tactical_model(
name: str,
methods: list,
seed=0,
numvoters=100,
cnum=3,
ndim=1,
tol=None,
ratio=1.0,
) -> spatial.Election:
"""Tactical Election model where voters use naive underdog prediction. """
e = spatial.Election(None, None, seed=seed, name=name)
# Construct base strategy
strategy_base = {}
strategy_base['ratio'] = ratio
strategy_base['underdog'] = None
# Generate voters
v = spatial.Voters(seed=seed, tol=tol, base='linear')
v.add_random(numvoters, ndim=ndim)
# Generate candidates
c = spatial.Candidates(v, seed=seed)
c.add_random(cnum, sdev=2.0)
e.set_models(voters=v, candidates=c)
# Construct election identification
eid = (
seed,
numvoters,
cnum,
ndim,
)
# Loop through election methods
for method in methods:
# Retrieve topdog strategy.
strategy_topdog = get_topdog_strategy1(method)
strategy_topdog['ratio'] = ratio
strategy_topdog['subset'] = 'topdog'
strategy_topdog['underdog'] = None
# First run the honest election
e.user_data(
eid=eid,
num_voters=numvoters,
num_candidates=cnum,
num_dimensions=ndim,
strat_id=-1,
onesided=False,
)
# Set empty (honest) strategy
e.set_models(strategies=spatial.StrategiesEmpty())
result1 = e.run(etype=method)
stats_honest = result1.stats
# honest_ballots = e.ballotgen.honest_ballots
# stats_honest = e.electionStats.copy()
# Initialize strategy elections
strategies = get_strategies1(method)
for s in strategies:
s.update(strategy_base)
# Iterate through available strategies
for ii, strategy in enumerate(strategies):
# Run one-sided strategy
strategy['subset'] = 'underdog'
s = spatial.Strategies(v).add(**strategy)
e.set_models(strategies=s)
e.user_data(eid=eid,
num_voters=numvoters,
num_candidates=cnum,
num_dimensions=ndim,
strat_id=ii,
onesided=True)
result2 = e.run(etype=method, result=result1)
# Create tactical comparison output, add to output
tactic_compare = TacticCompare(e_strat=result2.stats,
e_honest=stats_honest)
e.append_stat(tactic_compare)
# Run defensive topdog strategy
s = s.add(**strategy_topdog)
e.set_models(strategies=s)
e.user_data(
eid=eid,
num_voters=numvoters,
num_candidates=cnum,
num_dimensions=ndim,
strat_id=ii,
onesided=False,
)
result3 = e.run(etype=method, result=result1)
tactic_compare = TacticCompare(e_strat=result3.stats,
e_honest=stats_honest)
e.append_stat(tactic_compare)
return e
def __init__(self,
name: str,
method: str,
voters: spatial.Voters,
candidates: spatial.Candidates,
ratio=1.0,
frontrunnernum=2,
user_args: dict = None,
record: spatial.ResultRecord = None,
get_all_defense=False):
"""Tactical Election model """
if record is None:
record = spatial.ResultRecord()
# Construct base one-sided strategy
strategy1 = {}
strategy1['ratio'] = ratio
strategy1['frontrunnernum'] = frontrunnernum
strategy1['subset'] = 'underdog'
# Construct base two-sided strategy
strategy2 = {}
strategy2['ratio'] = ratio
strategy2['frontrunnernum'] = frontrunnernum
strategy2['subset'] = 'topdog'
#-------------------------------------------------------------------
# STEP1: HONEST LECTION SIMULATION
# Run honest election
e = spatial.Election(voters=voters,
candidates=candidates,
strategies=None,
save_records=False,
seed=0,
name=name)
e.user_data(user_args)
result1 = e.run(etype=method)
record.append(result1)
cnum = len(candidates.data.pref)
tactics = get_tactics(method)
self.vse_honest = result1.stats.winner.regret_efficiency_candidate
#-------------------------------------------------------------------
# STEP 2: ONE SIDED ELECTION SIMULATIONS
# Perform tactics on every candidate, see which one produces benefit
# to the candidate's supporters.
logger.info('Running one-sided simulations')
dvse_topdogs = []
dvse_underdogs = []
effective_list = []
vse_list1 = []
underdogs = []
for underdog in range(cnum):
strategy1['underdog'] = underdog
for tactic in tactics:
strategy1['tactics'] = tactic
strategies = spatial.Strategies(e.voters).add(strategy1, 0)
e.set_models(strategies=strategies)
result2 = e.run(etype=method, result=result1)
winner = result2.winners[0]
# Get underdog change in VSE (positive means the group benefited)
compare = TacticCompare(e_strat=result2.stats,
e_honest=result1.stats)
dvse_u = compare.regret_efficiency_candidate['underdog-0']
dvse_t = compare.regret_efficiency_candidate['topdog-0']
# record VSE
vse = result2.stats.winner.regret_efficiency_candidate
vse_list1.append(vse)
logger.debug('underdog #%s', underdog)
logger.debug('strategy = %s', tactic)
logger.debug(compare.voter_nums)
logger.debug('underdog VSE change = %.2f', dvse_u)
logger.debug('topdog VSE change = %.2f', dvse_t)
try:
dvse_u = float(dvse_u)
dvse_t = float(dvse_t)
except TypeError:
raise ValueError(
'Something went wrong with VSE calculation.')
# record tactic if it succeeds.
if dvse_u > 0 and winner == underdog:
dvse_underdogs.append(dvse_u)
dvse_topdogs.append(dvse_t)
effective_list.append(tactic)
underdogs.append(underdog)
record.append(result2)
record.append_stat(compare)
#-------------------------------------------------------------------
# STEP 3: TWO SIDED ELECTION SIMULATIONS
# If a one-sided tactic succeeds, see if a defensive counter exists.
logger.info('Running two-sided simulations')
vse_twosided_list = []
for ii in range(len(effective_list)):
dvse_topdog = dvse_topdogs[ii]
strategy1['tactics'] = effective_list[ii]
strategy1['underdog'] = underdogs[ii]
vse_list2 = []
for tactic2 in tactics:
strategy2['tactics'] = tactic2
strategy2['underdog'] = underdogs[ii]
strategies = spatial.Strategies(e.voters)
strategies.add(strategy1, 0)
strategies.add(strategy2, 0)
e.set_models(strategies=strategies)
result3 = e.run(etype=method, result=result1)
# Get change in VSE (positive means the group benefited)
compare = TacticCompare(e_strat=result3.stats,
e_honest=result1.stats)
dvse_u = compare.regret_efficiency_candidate['underdog-0']
dvse_t = compare.regret_efficiency_candidate['topdog-0']
vse = result3.stats.winner.regret_efficiency_candidate
vse_list2.append(vse)
logger.debug('tactic = %s', tactic2)
logger.debug('underdog VSE change = %.2f', dvse_u)
logger.debug('topdog VSE change = %.2f', dvse_t)
try:
dvse_u = float(dvse_u)
dvse_t = float(dvse_t)
except TypeError:
raise ValueError(
'Something went wrong with VSE calculation.')
if dvse_t > dvse_topdog:
record.append(result3)
record.append_stat(compare)
# If a defensive tactic is found to completely counter
# offense, break.
# if (dvse_u == 0) and (get_all_defense == False):
# break
vse_twosided = np.max(vse_list2)
vse_twosided_list.append(vse_twosided)
self.record = record
self.dvse_underdogs = dvse_underdogs
self.dvse_topdogs = dvse_topdogs
self.vse_onesided = np.min(vse_list1)
self.viable_underdogs = len(np.unique(underdogs))
try:
self.vse_twosided = np.min(vse_twosided_list)
except ValueError:
# If no values found that means underdog strategies were ineffective
# and therefore two-sided runs were not performed.
self.vse_twosided = self.vse_honest
self.df = record.dataframe()
return
def tactical_model(
name: str,
method: str,
seed=0,
numvoters=51,
cnum=5,
ndim=1,
tol=None,
ratio=1.0,
frontrunnernum=2,
) -> spatial.Election:
"""Tactical Election model """
e = spatial.Election(None, None, seed=seed, name=name)
# Construct base strategy
strategy_base = {}
strategy_base['ratio'] = ratio
strategy_base['frontrunnernum'] = frontrunnernum
strategy_base['frontrunnertype'] = 'eliminate'
# strategy_base['tactics'] = ('bury', 'compromise')
strategy_base['tactics'] = ('minmax_preferred')
strategy_base['subset'] = 'underdog'
strategy2 = strategy_base.copy()
# Generate voters
v = spatial.Voters(seed=seed, tol=tol, base='linear')
v.add_random(numvoters, ndim=ndim)
# Generate candidates
c = spatial.Candidates(v, seed=seed)
c.add_random(cnum, sdev=1.0)
e.set_models(voters=v, candidates=c)
# Set empty (honest) strategy
e.set_models(strategies=())
result1 = e.run(etype=method)
winner = result1.winners[0]
stats_honest = result1.stats
underdog_list = list(range(cnum))
underdog_list.remove(winner)
try:
print('honest tally')
print(result1.runner.output['tally'])
print('')
except KeyError:
pass
# test each underdog
for underdog in underdog_list:
# Run one-sided strategy
strategy2['underdog'] = underdog
s = spatial.Strategies(v).add(strategy2, 0)
e.set_models(strategies=s)
result2 = e.run(etype=method, result=result1)
# Create tactical comparison output, add to output
tactic_compare = TacticCompare(e_strat=result2.stats,
e_honest=stats_honest)
e.append_stat(tactic_compare)
series = e.dataseries()
out1 = series[statnames[0]]
out2 = series[statnames[1]]
print('Setting underdog = %s' % underdog)
print('Topdog VSE = %.2f' % out1)
print('Underdog VSE = %.2f' % out2)
print('winner=%s' % result2.winners[0])
try:
print('tally=', result2.runner.output['tally'])
except KeyError:
pass
# print(result2.ballots)
print('')
# Calculate underdog using tally
s0 = spatial.Strategies(v).add(strategy_base, 0)
e.set_models(voters=v, candidates=c, strategies=s0)
e.run(etype=method)
frunners = e.ballotgen.tacticalballots.root.get_group_frontrunners(s0.data)
print('calculated front runners (tally) = ', frunners)
#Calculate underdog using eliminate
strategy_base['frontrunnertype'] = 'eliminate'
s0 = spatial.Strategies(v).add(strategy_base, 0)
e.set_models(voters=v, candidates=c, strategies=s0)
e.run(etype=method)
frunners = e.ballotgen.tacticalballots.root.get_group_frontrunners(s0.data)
print('calculated front runners (eliminate) = ', frunners)
return e
def test_metrics_compare():
"""Test plurality bullet voting strategy.
Scenario attributes:
- 3 candidate race with 3 concentrated, coincident voter groups
>>> Candidates #0 #1 #2
>>> Preference locations = [-1, 0.5, 1]
>>> Number of voters = [ 7, 3, 5]
- If voters are honest, plurality candidate #0 should win with 7 votes
- If voters are strategic and consider only the top two candidates,
Candidate #1 supporters also lean towards #2 - therefore
candidate #2 should win with 3 + 5 = 8 votes.
"""
pref = [-1] * 7 + [0.5] * 3 + [1] * 5
pref = np.array(pref)[:, None]
v = spatial.Voters(seed=0)
v.add(pref)
cpref = [-1, .5, 1]
cpref = np.array(cpref)[:, None]
c = spatial.Candidates(v)
c.add(cpref)
#####################################################################
# Run honest election
e1 = spatial.Election(voters=v, candidates=c)
e1.run('plurality')
result1 = e1.result
estat1 = result1.stats
#####################################################################
# Run strategic election
strategy1 = {
'tactics': 'bullet_preferred',
'subset': '',
'ratio': 1,
'underdog': None
}
s = spatial.Strategies(v)
s.add(**strategy1)
e1.set_models(strategies=s)
e1.run('plurality', result=result1)
result2 = e1.result
estat2 = result2.stats
#####################################################################
# Run the assestions
tc = votesim.metrics.TacticCompare(estat2, estat1)
t = e1.ballotgen.tacticalballots
topdog_num = len(t.group_index['topdog-0'])
underdog_num = len(t.group_index['underdog-0'])
regret1 = estat1.winner.regret
regret2 = estat2.winner.regret
regret_change = tc.regret
# Make sure regret change adds up for tactical and honest voters
assert regret2 - regret1 == regret_change['tactical-0']
# Make sure group regrets add up for the total reget, honest.
regret_honest = tc._group_honest.regret
regret1a = ((regret_honest['topdog-0'] * topdog_num +
regret_honest['underdog-0'] * underdog_num) /
(topdog_num + underdog_num))
assert regret1a == regret1
# Make sure group regrets add up for the total reget, tactical.
regret_strate = tc._group_strate.regret
regret2a = ((regret_strate['topdog-0'] * topdog_num +
regret_strate['underdog-0'] * underdog_num) /
(topdog_num + underdog_num))
assert regret2a == regret2
return e1, estat2, estat1
tally = result1.runner.output['tally']
print('ballots = ')
print(result1.runner.ballots)
print('honest tally = ', tally)
print('candidate net regrets = ', result1.stats.candidates.regrets)
assert np.all(tally == [65, 59, 28])
print('---- ONE-SIDED ELECTION --------------------------------')
strat1 = {'tactics' : ('minmax_preferred'),
'frontrunnertype' : 'tally',
'subset' : 'underdog',
'ratio' : 1,
'underdog' : None,
'groupnum' : 0,
}
s1 = spatial.Strategies(v).add(**strat1)
e1.set_models(strategies=s1)
result2 = e1.run(etype)
tally = result2.runner.output['tally']
print('ballots = ')
print(result2.runner.ballots)
print('one-sided tactical tally = ', result2.runner.output['tally'])
assert np.all(tally == [45, 64, 25])
print('---- TWO-SIDED ELECTION --------------------------------')
strat2 = {'tactics' : ('minmax_preferred'),
'frontrunnertype' : 'tally',
'subset' : 'topdog',