def sampler(request):
if request.param == 'Metropolis':
return sample.MetropolisSampler()
elif request.param == 'AdaptiveMetropolis':
return sample.AdaptiveMetropolisSampler()
elif request.param == 'ParallelTempering':
return sample.ParallelTemperingSampler(
internal_sampler=sample.MetropolisSampler(), betas=[1, 1e-2, 1e-4])
elif request.param == 'AdaptiveParallelTempering':
return sample.AdaptiveParallelTemperingSampler(
internal_sampler=sample.AdaptiveMetropolisSampler(), n_chains=5)
elif request.param == 'Pymc3':
return sample.Pymc3Sampler(tune=5)
def test_empty_prior():
"""Check that priors are zero when none are defined."""
# define negative log posterior
posterior_fun = pypesto.Objective(fun=negative_log_posterior)
# define pypesto problem without prior object
test_problem = pypesto.Problem(objective=posterior_fun,
lb=-10,
ub=10,
x_names=['x'])
sampler = sample.AdaptiveMetropolisSampler()
result = sample.sample(
test_problem,
n_samples=50,
sampler=sampler,
x0=np.array([0.0]),
filename=None,
)
# get log prior values of first chain
logprior_trace = -result.sample_result.trace_neglogprior[0, :]
# check that all entries are zero
assert (logprior_trace == 0.0).all()
def test_ground_truth():
"""Test whether we actually retrieve correct distributions."""
# use best self-implemented sampler, which has a chance of correctly
# sample from the distribution
sampler = sample.AdaptiveParallelTemperingSampler(
internal_sampler=sample.AdaptiveMetropolisSampler(), n_chains=5)
problem = gaussian_problem()
result = optimize.minimize(problem, filename=None)
result = sample.sample(problem,
n_samples=5000,
result=result,
sampler=sampler,
filename=None)
# get samples of first chain
samples = result.sample_result.trace_x[0].flatten()
# test against different distributions
statistic, pval = kstest(samples, 'norm')
print(statistic, pval)
assert statistic < 0.1
statistic, pval = kstest(samples, 'uniform')
print(statistic, pval)
assert statistic > 0.1
def sample_petab_problem():
# create problem
problem = create_petab_problem()
sampler = sample.AdaptiveMetropolisSampler()
result = sample.sample(
problem,
n_samples=1000,
sampler=sampler,
x0=np.array([3, -4]),
filename=None,
)
return result
def test_prior():
"""Check that priors are defined for sampling."""
# define negative log posterior
posterior_fun = pypesto.Objective(fun=negative_log_posterior)
# define negative log prior
prior_fun = pypesto.Objective(fun=negative_log_prior)
# define pypesto prior object
prior_object = pypesto.NegLogPriors(objectives=[prior_fun])
# define pypesto problem using prior object
test_problem = pypesto.Problem(
objective=posterior_fun,
x_priors_defs=prior_object,
lb=-10,
ub=10,
x_names=['x'],
)
sampler = sample.AdaptiveMetropolisSampler()
result = sample.sample(
test_problem,
n_samples=1e4,
sampler=sampler,
x0=np.array([0.0]),
filename=None,
)
# get log prior values of first chain
logprior_trace = -result.sample_result.trace_neglogprior[0, :]
# check that not all entries are zero
assert (logprior_trace != 0.0).any()
# get samples of first chain
samples = result.sample_result.trace_x[0, :, 0]
# generate ground-truth samples
rvs = norm.rvs(size=5000, loc=-1.0, scale=np.sqrt(0.7))
# check sample distribution agreement with the ground-truth
statistic, pval = ks_2samp(rvs, samples)
print(statistic, pval)
assert statistic < 0.1
def test_storage_all():
"""Test `read_result` and `write_result`.
It currently does not test read/write of the problem as this
is know to not work completely. Also excludes testing the history
key of an optimization result.
"""
objective = pypesto.Objective(fun=so.rosen,
grad=so.rosen_der,
hess=so.rosen_hess)
dim_full = 10
lb = -5 * np.ones((dim_full, 1))
ub = 5 * np.ones((dim_full, 1))
n_starts = 5
problem = pypesto.Problem(objective=objective, lb=lb, ub=ub)
optimizer = optimize.ScipyOptimizer()
# Optimization
result = optimize.minimize(
problem=problem,
optimizer=optimizer,
n_starts=n_starts,
filename=None,
)
# Profiling
result = profile.parameter_profile(
problem=problem,
result=result,
profile_index=[0],
optimizer=optimizer,
filename=None,
)
# Sampling
sampler = sample.AdaptiveMetropolisSampler()
result = sample.sample(
problem=problem,
sampler=sampler,
n_samples=100,
result=result,
filename=None,
)
# Read and write
filename = 'test_file.hdf5'
try:
write_result(result=result, filename=filename)
result_read = read_result(filename=filename)
# test optimize
for i, opt_res in enumerate(result.optimize_result.list):
for key in opt_res:
if key == 'history':
continue
if isinstance(opt_res[key], np.ndarray):
np.testing.assert_array_equal(
opt_res[key], result_read.optimize_result.list[i][key])
else:
assert (opt_res[key] == result_read.optimize_result.list[i]
[key])
# test profile
for key in result.profile_result.list[0][0].keys():
if (result.profile_result.list[0][0].keys is None
or key == 'time_path'):
continue
elif isinstance(result.profile_result.list[0][0][key], np.ndarray):
np.testing.assert_array_equal(
result.profile_result.list[0][0][key],
result_read.profile_result.list[0][0][key],
)
elif isinstance(result.profile_result.list[0][0][key], int):
assert (result.profile_result.list[0][0][key] ==
result_read.profile_result.list[0][0][key])
# test sample
for key in result.sample_result.keys():
if result.sample_result[key] is None or key == 'time':
continue
elif isinstance(result.sample_result[key], np.ndarray):
np.testing.assert_array_equal(
result.sample_result[key],
result_read.sample_result[key],
)
elif isinstance(result.sample_result[key], (float, int)):
np.testing.assert_almost_equal(
result.sample_result[key],
result_read.sample_result[key],
)
finally:
if os.path.exists(filename):
os.remove(filename)
def test_storage_sampling():
"""
This test tests the saving and loading of samples
into HDF5 through pypesto.store.SamplingResultHDF5Writer
and pypesto.store.SamplingResultHDF5Reader. Tests all entries
aside from time and message.
"""
objective = pypesto.Objective(fun=so.rosen,
grad=so.rosen_der,
hess=so.rosen_hess)
dim_full = 10
lb = -5 * np.ones((dim_full, 1))
ub = 5 * np.ones((dim_full, 1))
n_starts = 5
startpoints = pypesto.startpoint.latin_hypercube(n_starts=n_starts,
lb=lb,
ub=ub)
problem = pypesto.Problem(objective=objective,
lb=lb,
ub=ub,
x_guesses=startpoints)
optimizer = optimize.ScipyOptimizer()
result_optimization = optimize.minimize(
problem=problem,
optimizer=optimizer,
n_starts=n_starts,
filename=None,
)
x_0 = result_optimization.optimize_result.list[0]['x']
sampler = sample.AdaptiveParallelTemperingSampler(
internal_sampler=sample.AdaptiveMetropolisSampler(), n_chains=1)
sample_original = sample.sample(
problem=problem,
sampler=sampler,
n_samples=100,
x0=[x_0],
filename=None,
)
fn = 'test_file.hdf5'
try:
pypesto_sample_writer = SamplingResultHDF5Writer(fn)
pypesto_sample_writer.write(sample_original)
pypesto_sample_reader = SamplingResultHDF5Reader(fn)
sample_read = pypesto_sample_reader.read()
for key in sample_original.sample_result.keys():
if sample_original.sample_result[key] is None or key == 'time':
continue
elif isinstance(sample_original.sample_result[key], np.ndarray):
np.testing.assert_array_equal(
sample_original.sample_result[key],
sample_read.sample_result[key],
)
elif isinstance(sample_original.sample_result[key], (float, int)):
np.testing.assert_almost_equal(
sample_original.sample_result[key],
sample_read.sample_result[key],
)
finally:
if os.path.exists(fn):
os.remove(fn)
def test_ground_truth_separated_modes():
"""Test whether we actually retrieve correct distributions."""
# use best self-implemented sampler, which has a chance to correctly
# sample from the distribution
# First use parallel tempering with 3 chains
sampler = sample.AdaptiveParallelTemperingSampler(
internal_sampler=sample.AdaptiveMetropolisSampler(), n_chains=3)
problem = gaussian_mixture_separated_modes_problem()
result = sample.sample(
problem,
n_samples=1e4,
sampler=sampler,
x0=np.array([0.0]),
filename=None,
)
# get samples of first chain
samples = result.sample_result.trace_x[0, :, 0]
# generate bimodal ground-truth samples
# "first" mode centered at -1
rvs1 = norm.rvs(size=5000, loc=-1.0, scale=np.sqrt(0.7))
# "second" mode centered at 100
rvs2 = norm.rvs(size=5001, loc=100.0, scale=np.sqrt(0.8))
# test for distribution similarity
statistic, pval = ks_2samp(np.concatenate([rvs1, rvs2]), samples)
# only parallel tempering finds both modes
print(statistic, pval)
assert statistic < 0.2
# sample using adaptive metropolis (single-chain)
# initiated around the "first" mode of the distribution
sampler = sample.AdaptiveMetropolisSampler()
result = sample.sample(
problem,
n_samples=1e4,
sampler=sampler,
x0=np.array([-2.0]),
filename=None,
)
# get samples of first chain
samples = result.sample_result.trace_x[0, :, 0]
# test for distribution similarity
statistic, pval = ks_2samp(np.concatenate([rvs1, rvs2]), samples)
# single-chain adaptive metropolis does not find both modes
print(statistic, pval)
assert statistic > 0.1
# actually centered at the "first" mode
statistic, pval = ks_2samp(rvs1, samples)
print(statistic, pval)
assert statistic < 0.1
# sample using adaptive metropolis (single-chain)
# initiated around the "second" mode of the distribution
sampler = sample.AdaptiveMetropolisSampler()
result = sample.sample(
problem,
n_samples=1e4,
sampler=sampler,
x0=np.array([120.0]),
filename=None,
)
# get samples of first chain
samples = result.sample_result.trace_x[0, :, 0]
# test for distribution similarity
statistic, pval = ks_2samp(np.concatenate([rvs1, rvs2]), samples)
# single-chain adaptive metropolis does not find both modes
print(statistic, pval)
assert statistic > 0.1
# actually centered at the "second" mode
statistic, pval = ks_2samp(rvs2, samples)
print(statistic, pval)
assert statistic < 0.1