def test_uniform_prior_sampling(self):
lower = np.array([1, 2])
upper = np.array([10, 20])
p = pints.UniformLogPrior(lower, upper)
# Test output formats
d = 2
n = 1
x = p.sample(n)
self.assertEqual(x.shape, (n, d))
n = 10
x = p.sample(n)
self.assertEqual(x.shape, (n, d))
p = pints.UniformLogPrior([0], [1])
d = 1
n = 1
x = p.sample(n)
self.assertEqual(x.shape, (n, d))
n = 10
x = p.sample(n)
self.assertEqual(x.shape, (n, d))
# Roughly check distribution (main checks are in numpy!)
np.random.seed(1)
p = pints.UniformLogPrior(lower, upper)
x = p.sample(10000)
self.assertTrue(np.all(lower <= x))
self.assertTrue(np.all(upper > x))
self.assertTrue(
np.linalg.norm(x.mean(axis=0) - 0.5 * (upper + lower)) < 0.1)
def figure2():
"""Make a figure for MCMC inference
"""
num_mcmc_iters = 10000
def stimulus(t):
return (1 * (t < 50)) + (-100 * (t >= 50) & (t < 75)) + (1 * (t >= 75))
# Generate data
y0 = np.array([0.0, 0.0])
m = diffeqinf.DampedOscillator(stimulus, y0, 'RK45')
m.set_tolerance(1e-8)
true_params = [1.0, 0.2, 1.0]
times = np.linspace(0, 100, 500)
y = m.simulate(true_params, times)
y += np.random.normal(0, 0.01, len(times))
# Run inference with correct model
problem = pints.SingleOutputProblem(m, times, y)
likelihood = pints.GaussianLogLikelihood(problem)
prior = pints.UniformLogPrior([0] * 4, [1e6] * 4)
posterior = pints.LogPosterior(likelihood, prior)
x0 = [true_params + [0.01]] * 3
mcmc = pints.MCMCController(posterior, 3, x0)
mcmc.set_max_iterations(num_mcmc_iters)
chains_correct = mcmc.run()
# Run inference with incorrect model
m.set_tolerance(1e-2)
problem = pints.SingleOutputProblem(m, times, y)
likelihood = pints.GaussianLogLikelihood(problem)
prior = pints.UniformLogPrior([0] * 4, [1e6] * 4)
posterior = pints.LogPosterior(likelihood, prior)
mcmc = pints.MCMCController(posterior, 3, x0)
mcmc.set_max_iterations(num_mcmc_iters)
chains_incorrect = mcmc.run()
# Plot MCMC chains
pints.plot.trace(chains_incorrect)
plt.show()
# Plot posteriors
diffeqinf.plot.plot_grouped_parameter_posteriors(
[chains_correct[0, num_mcmc_iters // 2:, :]],
[chains_incorrect[0, num_mcmc_iters // 2:, :]],
[chains_incorrect[1, num_mcmc_iters // 2:, :]],
[chains_incorrect[2, num_mcmc_iters // 2:, :]],
true_model_parameters=true_params,
method_names=[
'Correct', 'PoorTol_Chain1', 'PoorTol_Chain2', 'PoorTol_Chain3'
],
parameter_names=['k', 'c', 'm'],
fname=None)
plt.show()
def set_prior(self, name_value_dict):
"""
Organise the priors for free parameters.
The priors are pre-tested separately.
Parameters
----------
name_value_dict
Dictionary of fixed parameters with their values.
"""
prior_list = [
pints.UniformLogPrior(0, 100),
pints.UniformLogPrior(0, 10),
pints.UniformLogPrior(0, 10),
pints.UniformLogPrior(0, 100),
pints.UniformLogPrior(0, 1),
pints.UniformLogPrior(0, 1),
pints.UniformLogPrior(0, 1)
]
prior_dict = {
name: value
for (name, value) in zip(self.model._parameter_names, prior_list)
}
priors = []
for key in name_value_dict:
if name_value_dict[key] is None:
priors.append(prior_dict[key])
priors.append(pints.UniformLogPrior(0, 1))
return priors
def setUpClass(cls):
""" Prepare a problem for testing. """
# Random seed
np.random.seed(1)
# Create toy model
cls.model = toy.LogisticModel()
cls.real_parameters = [0.015, 500]
cls.times = np.linspace(0, 1000, 1000)
cls.values = cls.model.simulate(cls.real_parameters, cls.times)
# Add noise
cls.noise = 10
cls.values += np.random.normal(0, cls.noise, cls.values.shape)
cls.real_parameters.append(cls.noise)
cls.real_parameters = np.array(cls.real_parameters)
# Create an object with links to the model and time series
cls.problem = pints.SingleOutputProblem(cls.model, cls.times,
cls.values)
# Create a uniform prior over both the parameters and the new noise
# variable
cls.log_prior = pints.UniformLogPrior([0.01, 400, cls.noise * 0.1],
[0.02, 600, cls.noise * 100])
# Create a log likelihood
cls.log_likelihood = pints.GaussianLogLikelihood(cls.problem)
# Create an un-normalised log-posterior (log-likelihood + log-prior)
cls.log_posterior = pints.LogPosterior(cls.log_likelihood,
cls.log_prior)
def test_construction_errors(self):
# Tests if invalid constructor calls are picked up.
# First arg must be a log likelihood
self.assertRaisesRegex(ValueError, 'must extend pints.LogLikelihood',
pints.NestedController, 'hello', self.log_prior)
# First arg must be a log prior
self.assertRaisesRegex(ValueError, 'must extend pints.LogPrior',
pints.NestedController, self.log_likelihood,
self.log_likelihood)
# Both must have same number of parameters
log_prior = pints.UniformLogPrior([0.01, 400, 1], [0.02, 600, 3])
self.assertRaisesRegex(ValueError, 'same number of parameters',
pints.NestedController, self.log_likelihood,
log_prior)
# test that ellipsoidal sampling used by default
sampler = pints.NestedController(self.log_likelihood, self.log_prior)
self.assertEqual(sampler._sampler.name(), 'Nested ellipsoidal sampler')
self.assertRaisesRegex(
ValueError, 'Given method must extend pints.NestedSampler.',
pints.NestedController, self.log_likelihood, self.log_prior,
pints.DifferentialEvolutionMCMC)
self.assertRaisesRegex(
ValueError, 'Given method must extend pints.NestedSampler.',
pints.NestedController, self.log_likelihood, self.log_prior, 0.0)
def test_nparameters_error(self):
# Test that error is thrown when parameters from log prior and error
# measure do not match.
log_prior = pints.UniformLogPrior([0.0, 0, 0], [0.2, 100, 1])
self.assertRaises(ValueError, pints.ABCController, self.error_measure,
log_prior)
def __call__(self, x):
"""
Evaluates the log-prior in a PINTS framework.
"""
# Prior contribution for initial R
log_prior = pints.UniformLogPrior([0], [5])(x[0])
# Prior contribution for ICs
# log_prior += pints.UniformLogPrior([0], [1000])(x[-1])
# Variance for betas
sigma_b = x[-1]
log_prior += gamma.logpdf(sigma_b, 1, scale=1 / 100)
# Prior contriubution for betas
LEN = len(np.arange(44, len(self._times), 7))
for r in range(len(self._model.regions)):
log_prior += norm.logpdf(np.log(x[r * LEN + 1]),
loc=0,
scale=sigma_b)
for d in range(1, LEN):
log_prior += norm.logpdf(np.log(x[r * LEN + d + 1]),
loc=np.log(x[r * LEN + d]),
scale=sigma_b)
return log_prior
def test_method_near_boundary(self):
# Create log pdf
log_pdf = pints.UniformLogPrior([0, 0], [1, 1])
# Create mcmc
x0 = np.array([0.999, 0.999])
sigma = [[1, 0], [0, 1]]
mcmc = pints.NoUTurnMCMC(x0, sigma)
# Perform short run
chain = []
for i in range(2 * mcmc.number_adaption_steps()):
x = mcmc.ask()
fx, gr = log_pdf.evaluateS1(x)
sample = mcmc.tell((fx, gr))
if sample is not None:
chain.append(sample)
if np.all(sample == x):
self.assertEqual(mcmc.current_log_pdf(), fx)
chain = np.array(chain)
self.assertGreater(chain.shape[0], 1)
self.assertEqual(chain.shape[1], len(x0))
self.assertGreater(mcmc.divergent_iterations().shape[0], 0)
def setUpClass(cls):
""" Prepare problem for tests. """
# Load a forward model
model = pints.toy.LogisticModel()
# Create some toy data
real_parameters = [0.015, 500]
times = np.linspace(0, 1000, 1000)
org_values = model.simulate(real_parameters, times)
# Add noise
noise = 10
values = org_values + np.random.normal(0, noise, org_values.shape)
real_parameters = np.array(real_parameters + [noise])
# Create an object with links to the model and time series
problem = pints.SingleOutputProblem(model, times, values)
# Create an error measure
cls.score = pints.SumOfSquaresError(problem)
cls.boundaries = pints.RectangularBoundaries([0, 400], [0.05, 600])
# Create a log-likelihood function (adds an extra parameter!)
log_likelihood = pints.GaussianLogLikelihood(problem)
# Create a uniform prior over both the parameters and the new noise
cls.log_prior = pints.UniformLogPrior([0.01, 400, noise * 0.1],
[0.02, 600, noise * 100])
# Create a posterior log-likelihood (log(likelihood * prior))
cls.log_posterior = pints.LogPosterior(log_likelihood, cls.log_prior)
def setUpClass(cls):
""" Prepare for the test. """
# Create toy model
model = pints.toy.LogisticModel()
cls.real_parameters = [0.015, 500]
times = np.linspace(0, 1000, 1000)
values = model.simulate(cls.real_parameters, times)
# Add noise
np.random.seed(1)
cls.noise = 10
values += np.random.normal(0, cls.noise, values.shape)
cls.real_parameters.append(cls.noise)
# Create an object with links to the model and time series
problem = pints.SingleOutputProblem(model, times, values)
# Create a uniform prior over both the parameters and the new noise
# variable
cls.log_prior = pints.UniformLogPrior(
[0.01, 400],
[0.02, 600]
)
# Create a log-likelihood
cls.log_likelihood = pints.GaussianKnownSigmaLogLikelihood(
problem, cls.noise)
def test_build_tree_nan(self):
# This method gives nan in the hamiltonian_dash
# in the build_tree function
# Needed for coverage
model = pints.toy.LogisticModel()
real_parameters = np.array([0.015, 20])
times = np.linspace(0, 1000, 50)
org_values = model.simulate(real_parameters, times)
np.random.seed(1)
noise = 0.1
values = org_values + np.random.normal(0, noise, org_values.shape)
problem = pints.SingleOutputProblem(model, times, values)
log_likelihood = pints.GaussianKnownSigmaLogLikelihood(problem, noise)
log_prior = pints.UniformLogPrior([0.0001, 1], [1, 500])
log_posterior = pints.LogPosterior(log_likelihood, log_prior)
xs = [[0.36083914, 1.99013825]]
nuts_mcmc = pints.MCMCController(log_posterior,
len(xs),
xs,
method=pints.NoUTurnMCMC)
nuts_mcmc.set_max_iterations(50)
nuts_mcmc.set_log_to_screen(False)
np.random.seed(5)
nuts_chains = nuts_mcmc.run()
self.assertFalse(np.isnan(np.sum(nuts_chains)))
def test_method_near_boundary(self):
# Create log pdf
log_pdf = pints.UniformLogPrior([0, 0], [1, 1])
# Create mcmc
x0 = np.array([0.999, 0.999])
sigma = [[1, 0], [0, 1]]
mcmc = pints.NoUTurnMCMC(x0, sigma)
# Perform short run
chain = []
for i in range(2 * mcmc.number_adaption_steps()):
x = mcmc.ask()
fx, gr = log_pdf.evaluateS1(x)
reply = mcmc.tell((fx, gr))
if reply is not None:
y, fy, ac = reply
chain.append(y)
recalc = log_pdf.evaluateS1(y)
self.assertEqual(fy[0], recalc[0])
self.assertTrue(np.all(fy[1] == recalc[1]))
chain = np.array(chain)
self.assertGreater(chain.shape[0], 1)
self.assertEqual(chain.shape[1], len(x0))
self.assertGreater(mcmc.divergent_iterations().shape[0], 0)
def test_model_that_gives_nan(self):
# This model will return a nan in the gradient evaluation, which
# originally tripped up the find_reasonable_epsilon function in nuts.
# Run it for a bit so that we get coverage on the if statement!
model = pints.toy.LogisticModel()
real_parameters = model.suggested_parameters()
times = model.suggested_parameters()
org_values = model.simulate(real_parameters, times)
np.random.seed(1)
noise = 0.2
values = org_values + np.random.normal(0, noise, org_values.shape)
problem = pints.SingleOutputProblem(model, times, values)
log_likelihood = pints.GaussianKnownSigmaLogLikelihood(problem, noise)
log_prior = pints.UniformLogPrior([0.01, 40], [0.2, 60])
log_posterior = pints.LogPosterior(log_likelihood, log_prior)
xs = [real_parameters * 1.1]
nuts_mcmc = pints.MCMCController(log_posterior,
len(xs),
xs,
method=pints.NoUTurnMCMC)
nuts_mcmc.set_max_iterations(10)
nuts_mcmc.set_log_to_screen(False)
nuts_chains = nuts_mcmc.run()
self.assertFalse(np.isnan(np.sum(nuts_chains)))
def _make_pints_posterior(self):
"""Rebuild the Pints posterior and save it.
"""
# Build a uniform model prior if it is not supplied
if self.model_prior is None:
num_model_params = self.problem.n_parameters()
model_prior = pints.UniformLogPrior([-1e6] * num_model_params,
[1e6] * num_model_params)
# Get the GP prior
kernel_prior = NonstatGPLogPrior(
self.gp_times,
self.kernel.num_parameters() // len(self.gp_times), self.mu,
self.alpha, self.beta)
# Combine the two priors
log_prior = pints.ComposedLogPrior(model_prior, kernel_prior)
# Build the likelihood
log_likelihood = flexnoise.KernelCovarianceLogLikelihood(
self.problem, self.kernel)
# Build the posterior
log_posterior = pints.LogPosterior(log_likelihood, log_prior)
self.posterior = log_posterior
def test_composed_prior(self):
import pints
import numpy as np
m1 = 10
c1 = 2
p1 = pints.GaussianLogPrior(m1, c1)
m2 = -50
c2 = 100
p2 = pints.GaussianLogPrior(m2, c2)
p = pints.ComposedLogPrior(p1, p2)
# Test at center
peak1 = p1([m1])
peak2 = p2([m2])
self.assertEqual(p([m1, m2]), peak1 + peak2)
# Test at random points
np.random.seed(1)
for i in range(100):
x = np.random.normal(m1, c1)
y = np.random.normal(m2, c2)
self.assertAlmostEqual(p([x, y]), p1([x]) + p2([y]))
# Test effect of increasing covariance
p = [
pints.ComposedLogPrior(p1, pints.GaussianLogPrior(m2, c))
for c in range(1, 10)
]
p = [f([m1, m2]) for f in p]
self.assertTrue(np.all(p[:-1] > p[1:]))
# Test errors
self.assertRaises(ValueError, pints.ComposedLogPrior)
self.assertRaises(ValueError, pints.ComposedLogPrior, 1)
# Test derivatives
p = pints.ComposedLogPrior(p1, p2)
x = [8, -40]
y, dy = p.evaluateS1(x)
self.assertEqual(y, p(x))
self.assertEqual(dy.shape, (2, ))
y1, dy1 = p1.evaluateS1(x[:1])
y2, dy2 = p2.evaluateS1(x[1:])
self.assertAlmostEqual(dy[0], dy1[0])
self.assertAlmostEqual(dy[1], dy2[0])
# Test means
m1 = 10
c1 = 2
p1 = pints.GaussianLogPrior(m1, c1)
m2 = -50
c2 = 50
p2 = pints.UniformLogPrior(m2, c2)
p = pints.ComposedLogPrior(p1, p2)
self.assertTrue(np.array_equal(p.mean(), [10, 0]))
def test_error_measure_instance(self):
# Test that error is thrown when we use an error measure which is not
# an instance of ``pints.ErrorMeasure``.
# Set a log prior as the error measure to trigger the warning
wrong_error_measure = pints.UniformLogPrior([0.0, 0, 0], [0.2, 100, 1])
self.assertRaises(ValueError, pints.ABCController, wrong_error_measure,
self.log_prior)
def sample(self, x, parallel=False):
"""
Runs the sampler, this method:
(1) generates simulated data and adds noise
(2) sets up the sampler with the method given,
using an KnownNoiseLogLikelihood, and a UniformLogPrior
(3) runs the sampler
(4) returns:
- the calculated rhat value
- the average of ess across all chains, returning the
minimum result across all parameters
- the total time taken by the sampler
"""
the_model = self.model()
values = the_model.simulate(self.real_parameters, self.times)
value_range = np.max(values) - np.min(values)
values += np.random.normal(0, self.noise * value_range, values.shape)
problem = pints.MultiOutputProblem(the_model, self.times, values)
log_likelihood = pints.KnownNoiseLogLikelihood(
problem, value_range * self.noise)
# lower = list(self.lower) + [value_range *
# self.noise / 10.0]*the_model.n_outputs()
#upper = list(self.upper) + [value_range * self.noise * 10]*the_model.n_outputs()
lower = list(self.lower)
upper = list(self.upper)
middle = [0.5 * (u + l) for l, u in zip(lower, upper)]
sigma = [u - l for l, u in zip(lower, upper)]
log_prior = pints.UniformLogPrior(lower, upper)
log_posterior = pints.LogPosterior(log_likelihood, log_prior)
n_chains = int(x[-1])
xs = [[
np.random.uniform() * (u - l) + l for l, u in zip(lower, upper)
] for c in range(n_chains)]
mcmc = pints.MCMCSampling(log_posterior,
n_chains,
xs,
method=self.method)
[sampler.set_hyper_parameters(x[:-1]) for sampler in mcmc.samplers()]
if parallel:
mcmc.set_parallel(int(os.environ['OMP_NUM_THREADS']))
mcmc.set_log_interval(1000)
start = timer()
chains = mcmc.run()
end = timer()
rhat = np.max(pints._diagnostics.rhat_all_params(chains))
ess = np.zeros(chains[0].shape[1])
for chain in chains:
ess += np.array(pints._diagnostics.effective_sample_size(chain))
ess /= n_chains
ess = np.min(ess)
print('rhat:', rhat)
print('ess:', ess)
print('time:', end - start)
return rhat, ess, end - start
def setUpClass(cls):
cls.kernel = flexnoise.kernels.LaplacianKernel
cls.model = pints.toy.ConstantModel(1)
cls.times = np.arange(1, 91)
cls.data = np.hstack(
(np.random.normal(2.0, 0.1, 30), np.random.normal(2.0, 2.0, 30),
np.random.normal(2.0, 0.1, 30)))
cls.problem = pints.SingleOutputProblem(cls.model, cls.times, cls.data)
cls.model_prior = pints.UniformLogPrior([0] * 1, [1e6] * 1)
def test_uniform_prior_icdf(self):
lower = np.array([1, 2])
upper = np.array([11, 22])
log_prior = pints.UniformLogPrior(lower, upper)
self.assertEqual(log_prior.icdf([0.4, 0.9])[0], 5.0)
self.assertEqual(log_prior.icdf([0.4, 0.9])[1], 20.0)
self.assertEqual(log_prior.icdf(np.array([0.4, 0.9]))[1], 20.0)
self.assertEqual(log_prior.icdf([[0.1, 0.3], [0.2, 0.4]]).shape[0], 2)
self.assertRaises(ValueError, log_prior.icdf, [[1]])
self.assertRaises(ValueError, log_prior.icdf, [[1, 2, 3, 4]])
log_prior = pints.UniformLogPrior(1, 3)
self.assertEqual(log_prior.icdf(1), 3.0)
self.assertEqual(log_prior.icdf(0), 1.0)
self.assertEqual(log_prior.icdf(0.75), 2.5)
self.assertEqual(len(log_prior.icdf([[0.1], [0.2]])), 2)
self.assertEqual(log_prior.icdf([[0.5], [0.75]])[1],
log_prior.icdf(0.75))
def create_pints_prior(self):
noise_parameters = self.get_noise_params()
if self.form == self.Form.UNIFORM:
lower = noise_parameters[0]
upper = noise_parameters[1]
pints_log_prior = pints.UniformLogPrior(lower, upper)
elif self.form == self.Form.NORMAL:
mean = noise_parameters[0]
sd = noise_parameters[1]
pints_log_prior = pints.GaussianLogPrior(mean, sd)
return pints_log_prior
def test_uniform_prior_cdf(self):
lower = np.array([1, 2])
upper = np.array([11, 22])
log_prior = pints.UniformLogPrior(lower, upper)
self.assertEqual(log_prior.cdf([2, 19.0])[0], 0.1)
self.assertEqual(log_prior.cdf([2, 19.0])[1], 0.85)
self.assertEqual(log_prior.cdf(np.array([2, 19.0]))[1], 0.85)
self.assertEqual(log_prior.cdf([[1, 2], [2, 3]]).shape[0], 2)
# test errors
self.assertRaises(ValueError, log_prior.cdf, [[1]])
self.assertRaises(ValueError, log_prior.cdf, [[1, 2, 3, 4]])
log_prior = pints.UniformLogPrior(1, 3)
self.assertEqual(log_prior.cdf(1), 0)
self.assertEqual(log_prior.cdf(2), 0.5)
self.assertEqual(log_prior.cdf(3), 1.0)
# test multiple samples
self.assertEqual(len(log_prior.cdf([[1], [2]])), 2)
self.assertEqual(log_prior.cdf([[1], [2]])[1], log_prior.cdf(2))
def run_figureS2(num_runs=3, output_dir='./'):
"""Run the Gaussian process on block noise data.
This function runs the simulations and saves the results to pickle.
"""
random.seed(12345)
np.random.seed(12345)
all_fits = []
iid_runs = []
sigmas = []
mult_runs = []
gp_runs = []
for run in range(num_runs):
# Make a synthetic time series
times, values, data = generate_time_series(model='logistic',
noise='blocks',
n_times=625)
# Make Pints model and problem
model = pints.toy.LogisticModel()
problem = pints.SingleOutputProblem(model, times, data)
# Initial conditions for model parameters
model_starting_point = [0.08, 50]
# Infer the nonstationary kernel fit
# Run an optimization assumming IID
log_prior = pints.UniformLogPrior([0] * 3, [1e6] * 3)
log_likelihood = pints.GaussianLogLikelihood(problem)
log_posterior = pints.LogPosterior(log_likelihood, log_prior)
opt = pints.OptimisationController(log_posterior,
model_starting_point + [2])
xbest, fbest = opt.run()
# Run the GP fit, using the best fit for initialization
gp_times = times[::25]
kernel = flexnoise.kernels.GPLaplacianKernel
gnp = flexnoise.GPNoiseProcess(problem, kernel, xbest[:2], gp_times)
gnp.set_gp_hyperparameters(mu=0.0, alpha=1.0, beta_num_points=200)
x = gnp.run_optimize(num_restarts=100, parallel=True, maxiter=150)
all_fits.append(x)
# Save all results to pickle
kernel = kernel(None, gp_times)
results = [all_fits, times, data, values, model, problem, kernel]
fname = os.path.join(output_dir, 'figS2_data.pkl')
with open(fname, 'wb') as f:
pickle.dump(results, f)
def setUpClass(cls):
""" Set up problem for tests. """
# Create toy model
cls.model = toy.LogisticModel()
cls.real_parameters = [0.015, 500]
cls.times = np.linspace(0, 1000, 1000)
cls.values = cls.model.simulate(cls.real_parameters, cls.times)
# Add noise
cls.noise = 10
cls.values += np.random.normal(0, cls.noise, cls.values.shape)
cls.real_parameters.append(cls.noise)
cls.real_parameters = np.array(cls.real_parameters)
# Create an object with links to the model and time series
cls.problem = pints.SingleOutputProblem(cls.model, cls.times,
cls.values)
# Create a uniform prior over both the parameters and the new noise
# variable
cls.log_prior = pints.UniformLogPrior([0.01, 400, cls.noise * 0.1],
[0.02, 600, cls.noise * 100])
# Create a log likelihood
cls.log_likelihood = pints.GaussianLogLikelihood(cls.problem)
# Create an un-normalised log-posterior (log-likelihood + log-prior)
cls.log_posterior = pints.LogPosterior(cls.log_likelihood,
cls.log_prior)
# Run MCMC sampler
xs = [
cls.real_parameters * 1.1,
cls.real_parameters * 0.9,
cls.real_parameters * 1.15,
]
mcmc = pints.MCMCController(cls.log_posterior,
3,
xs,
method=pints.HaarioBardenetACMC)
mcmc.set_max_iterations(200)
mcmc.set_initial_phase_iterations(50)
mcmc.set_log_to_screen(False)
start = time.time()
cls.chains = mcmc.run()
end = time.time()
cls.time = end - start
def test_log_posterior(self):
# Create a toy problem and log likelihood
model = pints.toy.LogisticModel()
real_parameters = [0.015, 500]
x = [0.014, 501]
sigma = 0.001
times = np.linspace(0, 1000, 100)
values = model.simulate(real_parameters, times)
problem = pints.SingleOutputProblem(model, times, values)
log_likelihood = pints.GaussianKnownSigmaLogLikelihood(problem, sigma)
# Create a prior
log_prior = pints.UniformLogPrior([0, 0], [1, 1000])
# Test
p = pints.LogPosterior(log_likelihood, log_prior)
self.assertEqual(p(x), log_likelihood(x) + log_prior(x))
y = [-1, 500]
self.assertEqual(log_prior(y), -float('inf'))
self.assertEqual(p(y), -float('inf'))
self.assertEqual(p(y), log_prior(y))
# Test derivatives
log_prior = pints.ComposedLogPrior(pints.GaussianLogPrior(0.015, 0.3),
pints.GaussianLogPrior(500, 100))
log_posterior = pints.LogPosterior(log_likelihood, log_prior)
x = [0.013, 540]
y, dy = log_posterior.evaluateS1(x)
self.assertEqual(y, log_posterior(x))
self.assertEqual(dy.shape, (2, ))
y1, dy1 = log_prior.evaluateS1(x)
y2, dy2 = log_likelihood.evaluateS1(x)
self.assertTrue(np.all(dy == dy1 + dy2))
# Test getting the prior and likelihood back again
self.assertIs(log_posterior.log_prior(), log_prior)
self.assertIs(log_posterior.log_likelihood(), log_likelihood)
# First arg must be a LogPDF
self.assertRaises(ValueError, pints.LogPosterior, 'hello', log_prior)
# Second arg must be a log_prior
self.assertRaises(ValueError, pints.LogPosterior, log_likelihood,
log_likelihood)
# Prior and likelihood must have same dimension
self.assertRaises(ValueError, pints.LogPosterior, log_likelihood,
pints.GaussianLogPrior(0.015, 0.3))
def test_transformed_log_prior(self):
# Test TransformedLogPrior class
d = 2
t = pints.LogTransformation(2)
r = pints.UniformLogPrior([0.1, 0.1], [0.9, 0.9])
tr = t.convert_log_prior(r)
# Test sample
n = 1
x = tr.sample(n)
self.assertEqual(x.shape, (n, d))
self.assertTrue(np.all(x < 0.))
n = 1000
x = tr.sample(n)
self.assertEqual(x.shape, (n, d))
self.assertTrue(np.all(x < 0.))
def setUpClass(cls):
""" Prepare problem for tests. """
# Create toy model
cls.model = pints.toy.stochastic.DegradationModel()
cls.real_parameters = [0.1]
cls.times = np.linspace(0, 10, 10)
cls.values = cls.model.simulate(cls.real_parameters, cls.times)
# Create an object (problem) with links to the model and time series
cls.problem = pints.SingleOutputProblem(cls.model, cls.times,
cls.values)
# Create a uniform prior over both the parameters
cls.log_prior = pints.UniformLogPrior([0.0], [0.3])
# Set error measure
cls.error_measure = pints.RootMeanSquaredError(cls.problem)
def test_construction_errors(self):
""" Tests if invalid constructor calls are picked up. """
# First arg must be a log likelihood
self.assertRaisesRegex(ValueError, 'must extend pints.LogLikelihood',
pints.NestedRejectionSampler, 'hello',
self.log_prior)
# First arg must be a log prior
self.assertRaisesRegex(ValueError, 'must extend pints.LogPrior',
pints.NestedRejectionSampler,
self.log_likelihood, self.log_likelihood)
# Both must have same number of parameters
log_prior = pints.UniformLogPrior([0.01, 400, 1], [0.02, 600, 3])
self.assertRaisesRegex(ValueError, 'same number of parameters',
pints.NestedRejectionSampler,
self.log_likelihood, log_prior)
def test_composed_prior_cdf_icdf(self):
p1 = pints.GaussianLogPrior(-3, 7)
p2 = pints.UniformLogPrior(-4, -1)
p = pints.ComposedLogPrior(p1, p2)
ps = [p1, p2]
xs = [-10, -3]
cdfs = p.cdf(xs)
for i, cdf in enumerate(cdfs):
self.assertEqual(cdf, ps[i].cdf(xs[i]))
cdfs1 = p.convert_to_unit_cube(xs)
self.assertEqual(cdfs[0], cdfs1[0])
self.assertEqual(cdfs[1], cdfs1[1])
qs = [0.3, 0.75]
icdfs = p.icdf(qs)
for i, icdf in enumerate(icdfs):
self.assertEqual(icdf, ps[i].icdf(qs[i]))
icdfs1 = p.convert_from_unit_cube(qs)
self.assertEqual(icdfs[0], icdfs1[0])
self.assertEqual(icdfs[1], icdfs1[1])
def setUpClass(cls):
""" Set up problem for tests. """
# Create toy model
cls.model = toy.stochastic.DegradationModel()
cls.real_parameters = [0.1]
cls.times = np.linspace(0, 10, 10)
cls.values = cls.model.simulate(cls.real_parameters, cls.times)
# Create an object (problem) with links to the model and time series
cls.problem = pints.SingleOutputProblem(cls.model, cls.times,
cls.values)
# Create a uniform prior over both the parameters
cls.log_prior = pints.UniformLogPrior([0.0], [0.3])
cls.transition_kernel = pints.MultivariateGaussianLogPrior(
np.zeros(1), 0.001 * np.identity(1))
# Set error measure
cls.error_measure = pints.RootMeanSquaredError(cls.problem)
def test_basic(self):
# Create a custom LogPDF for testing
class Gradient(pints.LogPDF):
def n_parameters(self):
return 1
def __call__(self, x):
return x
# Create boundaries based on gradient
b = pints.LogPDFBoundaries(Gradient(), 0.75)
# Test n_parameters
self.assertEqual(b.n_parameters(), 1)
# Test
self.assertFalse(b.check(0))
self.assertFalse(b.check(-1))
self.assertTrue(b.check(2))
self.assertTrue(b.check(1))
self.assertFalse(b.check(0.75))
# Test bad creation
self.assertRaisesRegexp(
ValueError, 'must be a pints.LogPDF', pints.LogPDFBoundaries, 5, 5)
# Can't sample from this log pdf!
self.assertRaises(NotImplementedError, b.sample, 1)
# Can sample if we have a prior that supports it
b = pints.RectangularBoundaries([1, 1], [2, 2])
p = pints.UniformLogPrior(b)
p.sample(2)
b = pints.LogPDFBoundaries(p)
b.sample(2)