def check_convergence_and_learn_proposal(self):
"""
Checks the convergence of the sampling process, and, if requested,
learns a new covariance matrix for the proposal distribution from the covariance
of the last samples.
"""
# Compute Rminus1 of means
self.been_waiting = 0
if more_than_one_process():
# Compute and gather means and covs
use_first = int(self.n() / 2)
mean = self.collection.mean(first=use_first)
cov = self.collection.cov(first=use_first)
acceptance_rate = self.get_acceptance_rate(use_first)
Ns, means, covs, acceptance_rates = mpi.array_gather(
[self.n(), mean, cov, acceptance_rate])
else:
# Compute and gather means, covs and CL intervals of last m-1 chain fractions
m = 1 + self.Rminus1_single_split
cut = int(len(self.collection) / m)
try:
acceptance_rate = self.get_acceptance_rate(cut)
Ns = np.ones(m - 1) * cut
means = np.array([
self.collection.mean(first=i * cut, last=(i + 1) * cut - 1)
for i in range(1, m)
])
covs = np.array([
self.collection.cov(first=i * cut, last=(i + 1) * cut - 1)
for i in range(1, m)
])
except:
self.log.info(
"Not enough points in chain to check convergence. "
"Waiting for next checkpoint.")
return
acceptance_rates = None
if is_main_process():
self.progress.at[self.i_learn, "N"] = sum(Ns)
self.progress.at[self.i_learn, "timestamp"] = \
datetime.datetime.now().isoformat()
acceptance_rate = (np.average(acceptance_rates, weights=Ns)
if acceptance_rates is not None else
acceptance_rate)
self.log.info(
" - Acceptance rate: %.3f" +
(" = avg(%r)" % list(acceptance_rates)
if acceptance_rates is not None else ""), acceptance_rate)
self.progress.at[self.i_learn, "acceptance_rate"] = acceptance_rate
# "Within" or "W" term -- our "units" for assessing convergence
# and our prospective new covariance matrix
mean_of_covs = np.average(covs, weights=Ns, axis=0)
# "Between" or "B" term
# We don't weight with the number of samples in the chains here:
# shorter chains will likely be outliers, and we want to notice them
cov_of_means = np.atleast_2d(np.cov(means.T)) # , fweights=Ns)
# For numerical stability, we turn mean_of_covs into correlation matrix:
# rho = (diag(Sigma))^(-1/2) * Sigma * (diag(Sigma))^(-1/2)
# and apply the same transformation to the mean of covs (same eigenvals!)
d = np.sqrt(np.diag(cov_of_means))
corr_of_means = (cov_of_means / d).T / d
norm_mean_of_covs = (mean_of_covs / d).T / d
success_means = False
converged_means = False
# Cholesky of (normalized) mean of covs and eigvals of Linv*cov_of_means*L
try:
L = np.linalg.cholesky(norm_mean_of_covs)
except np.linalg.LinAlgError:
self.log.warning(
"Negative covariance eigenvectors. "
"This may mean that the covariance of the samples does not "
"contain enough information at this point. "
"Skipping learning a new covmat for now.")
else:
Linv = np.linalg.inv(L)
try:
eigvals = np.linalg.eigvalsh(
Linv.dot(corr_of_means).dot(Linv.T))
success_means = True
except np.linalg.LinAlgError:
self.log.warning("Could not compute eigenvalues. "
"Skipping learning a new covmat for now.")
else:
Rminus1 = max(np.abs(eigvals))
self.progress.at[self.i_learn, "Rminus1"] = Rminus1
# For real square matrices, a possible def of the cond number is:
condition_number = Rminus1 / min(np.abs(eigvals))
self.log.debug(" - Condition number = %g",
condition_number)
self.log.debug(" - Eigenvalues = %r", eigvals)
self.log.info(
" - Convergence of means: R-1 = %f after %d accepted steps"
% (Rminus1, sum(Ns)) +
(" = sum(%r)" %
list(Ns) if more_than_one_process() else ""))
# Have we converged in means?
# (criterion must be fulfilled twice in a row)
converged_means = max(
Rminus1, self.Rminus1_last) < self.Rminus1_stop
else:
mean_of_covs = None
success_means = None
converged_means = False
Rminus1 = None
success_means, converged_means = mpi.share(
(success_means, converged_means))
# Check the convergence of the bounds of the confidence intervals
# Same as R-1, but with the rms deviation from the mean bound
# in units of the mean standard deviation of the chains
if converged_means:
if more_than_one_process():
mcsamples = self.collection.sampled_to_getdist_mcsamples(
first=use_first)
try:
bound = np.array([[
mcsamples.confidence(i,
limfrac=self.Rminus1_cl_level /
2.,
upper=which)
for i in range(self.model.prior.d())
] for which in [False, True]]).T
success_bounds = True
except:
bound = None
success_bounds = False
bounds = np.array(mpi.gather(bound))
else:
try:
mcsamples_list = [
self.collection.sampled_to_getdist_mcsamples(
first=i * cut, last=(i + 1) * cut - 1)
for i in range(1, m)
]
except:
self.log.info(
"Not enough points in chain to check c.l. convergence. "
"Waiting for next checkpoint.")
return
try:
bounds = [
np.array([[
mcs.confidence(i,
limfrac=self.Rminus1_cl_level / 2.,
upper=which)
for i in range(self.model.prior.d())
] for which in [False, True]]).T
for mcs in mcsamples_list
]
success_bounds = True
except:
bounds = None
success_bounds = False
if is_main_process():
if success_bounds:
Rminus1_cl = (np.std(bounds, axis=0).T /
np.sqrt(np.diag(mean_of_covs)))
self.log.debug(" - normalized std's of bounds = %r",
Rminus1_cl)
Rminus1_cl = np.max(Rminus1_cl)
self.progress.at[self.i_learn, "Rminus1_cl"] = Rminus1_cl
self.log.info(
" - Convergence of bounds: R-1 = %f after %d " %
(Rminus1_cl,
(sum(Ns) if more_than_one_process() else self.n())) +
"accepted steps" +
(" = sum(%r)" %
list(Ns) if more_than_one_process() else ""))
if Rminus1_cl < self.Rminus1_cl_stop:
self.converged = True
self.log.info("The run has converged!")
self._Ns = Ns
else:
self.log.info(
"Computation of the bounds was not possible. "
"Waiting until the next converge check.")
# Broadcast and save the convergence status and the last R-1 of means
if success_means:
self.Rminus1_last, self.converged = mpi.share((
Rminus1, self.converged) if is_main_process() else None)
# Do we want to learn a better proposal pdf?
if self.learn_proposal and not self.converged:
good_Rminus1 = (self.learn_proposal_Rminus1_max >
self.Rminus1_last >
self.learn_proposal_Rminus1_min)
if not good_Rminus1:
self.mpi_info(
"Convergence less than requested for updates: "
"waiting until the next convergence check.")
return
mean_of_covs = mpi.share(mean_of_covs)
try:
self.proposer.set_covariance(mean_of_covs)
self.mpi_info(
" - Updated covariance matrix of proposal pdf.")
self.mpi_debug("%r", mean_of_covs)
except:
self.mpi_debug(
"Updating covariance matrix failed unexpectedly. "
"waiting until next covmat learning attempt.")
# Save checkpoint info
self.write_checkpoint()
def __init__(self,
info_sampler,
model,
output=None,
packages_path=None,
name=None):
"""
Actual initialization of the class. Loads the default and input information and
call the custom ``initialize`` method.
[Do not modify this one.]
"""
self.model = model
self.output = output
self._updated_info = deepcopy_where_possible(info_sampler)
super().__init__(info_sampler,
packages_path=packages_path,
name=name,
initialize=False,
standalone=False)
# Seed, if requested
if getattr(self, "seed", None) is not None:
if not isinstance(self.seed,
int) or not (0 <= self.seed <= 2**32 - 1):
raise LoggedError(
self.log,
"Seeds must be a *positive integer* < 2**32 - 1, "
"but got %r with type %r", self.seed, type(self.seed))
# MPI-awareness: sum the rank to the seed
if more_than_one_process():
self.seed += get_mpi_rank()
self.mpi_warning("This run has been SEEDED with seed %d",
self.seed)
# Load checkpoint info, if resuming
if self.output.is_resuming() and not isinstance(self, Minimizer):
try:
checkpoint_info = yaml_load_file(self.checkpoint_filename())
try:
for k, v in checkpoint_info[kinds.sampler][
self.get_name()].items():
setattr(self, k, v)
self.mpi_info("Resuming from previous sample!")
except KeyError:
if is_main_process():
raise LoggedError(
self.log, "Checkpoint file found at '%s' "
"but it corresponds to a different sampler.",
self.checkpoint_filename())
except (IOError, TypeError):
pass
else:
try:
os.remove(self.checkpoint_filename())
os.remove(self.progress_filename())
except (OSError, TypeError):
pass
self._set_rng()
self.initialize()
self._release_rng()
self.model.set_cache_size(self._get_requested_cache_size())
# Add to the updated info some values which are
# only available after initialisation
self._updated_info[_version] = self.get_version()
def run(self):
"""
Runs the sampler.
"""
self.mpi_info("Sampling!" + (
" (NB: no accepted step will be saved until %d burn-in samples " %
self.burn_in.value +
"have been obtained)" if self.burn_in.value else ""))
self.n_steps_raw = 0
last_output: float = 0
last_n = self.n()
state_check_every = 1
with mpi.ProcessState(self) as state:
while last_n < self.max_samples and not self.converged:
self.get_new_sample()
self.n_steps_raw += 1
if self.output_every.unit:
# if output_every in sec, print some info
# and dump at fixed time intervals
now = datetime.datetime.now()
now_sec = now.timestamp()
if now_sec >= last_output + self.output_every.value:
self.do_output(now)
last_output = now_sec
state.check_error()
if self.current_point.weight == 1:
# have added new point
# Callback function
n = self.n()
if n != last_n:
# and actually added
last_n = n
if (self.callback_function
and not (max(n, 1) % self.callback_every.value)
and self.current_point.weight == 1):
self.callback_function_callable(self)
self.last_point_callback = len(self.collection)
if more_than_one_process():
# Checking convergence and (optionally) learning
# the covmat of the proposal
if self.check_ready() and state.set(
mpi.State.READY):
self.log.info(self._msg_ready +
" (waiting for the rest...)")
if state.all_ready():
self.mpi_info("All chains are r%s",
self._msg_ready[1:])
self.check_convergence_and_learn_proposal()
self.i_learn += 1
else:
if self.check_ready():
self.log.debug(self._msg_ready)
self.check_convergence_and_learn_proposal()
self.i_learn += 1
elif self.current_point.weight % state_check_every == 0:
state.check_error()
# more frequent checks near beginning
state_check_every = min(10, state_check_every + 1)
if last_n == self.max_samples:
self.log.info(
"Reached maximum number of accepted steps allowed (%s). "
"Stopping.", self.max_samples)
# Write the last batch of samples ( < output_every (not in sec))
self.collection.out_update()
ns = mpi.gather(self.n())
self.mpi_info("Sampling complete after %d accepted steps.", sum(ns))
def initialize(self):
self.mpi_info("Initializing")
self.max_evals = read_dnumber(self.max_evals, self.model.prior.d())
# Configure target
method = self.model.loglike if self.ignore_prior else self.model.logpost
kwargs = {"make_finite": True}
if self.ignore_prior:
kwargs["return_derived"] = False
self.logp = lambda x: method(x, **kwargs)
# Try to load info from previous samples.
# If none, sample from reference (make sure that it has finite like/post)
initial_point = None
if self.output:
files = self.output.find_collections()
collection_in = None
if files:
if more_than_one_process():
if 1 + get_mpi_rank() <= len(files):
collection_in = Collection(self.model,
self.output,
name=str(1 +
get_mpi_rank()),
resuming=True)
else:
collection_in = self.output.load_collections(
self.model, concatenate=True)
if collection_in:
initial_point = (collection_in.bestfit()
if self.ignore_prior else collection_in.MAP())
initial_point = initial_point[list(
self.model.parameterization.sampled_params())].values
self.log.info("Starting from %s of previous chain:",
"best fit" if self.ignore_prior else "MAP")
if initial_point is None:
this_logp = -np.inf
while not np.isfinite(this_logp):
initial_point = self.model.prior.reference()
this_logp = self.logp(initial_point)
self.log.info("Starting from random initial point:")
self.log.info(
dict(
zip(self.model.parameterization.sampled_params(),
initial_point)))
self._bounds = self.model.prior.bounds(
confidence_for_unbounded=self.confidence_for_unbounded)
# TODO: if ignore_prior, one should use *like* covariance (this is *post*)
covmat = self._load_covmat(self.output)[0]
# scale by conditional parameter widths (since not using correlation structure)
scales = np.minimum(1 / np.sqrt(np.diag(np.linalg.inv(covmat))),
(self._bounds[:, 1] - self._bounds[:, 0]) / 3)
# Cov and affine transformation
# Transform to space where initial point is at centre, and cov is normalised
# Cannot do rotation, as supported minimization routines assume bounds aligned
# with the parameter axes.
self._affine_transform_matrix = np.diag(1 / scales)
self._inv_affine_transform_matrix = np.diag(scales)
self._scales = scales
self._affine_transform_baseline = initial_point
initial_point = self.affine_transform(initial_point)
np.testing.assert_allclose(initial_point,
np.zeros(initial_point.shape))
bounds = np.array(
[self.affine_transform(self._bounds[:, i]) for i in range(2)]).T
# Configure method
if self.method.lower() == "bobyqa":
self.minimizer = pybobyqa.solve
self.kwargs = {
"objfun": (lambda x: -self.logp_transf(x)),
"x0":
initial_point,
"bounds":
np.array(list(zip(*bounds))),
"seek_global_minimum":
(True if get_mpi_size() in [0, 1] else False),
"maxfun":
int(self.max_evals)
}
self.kwargs = recursive_update(deepcopy(self.kwargs),
self.override_bobyqa or {})
self.log.debug(
"Arguments for pybobyqa.solve:\n%r",
{k: v
for k, v in self.kwargs.items() if k != "objfun"})
elif self.method.lower() == "scipy":
self.minimizer = scpminimize
self.kwargs = {
"fun": (lambda x: -self.logp_transf(x)),
"x0": initial_point,
"bounds": bounds,
"options": {
"maxiter": self.max_evals,
"disp": (self.log.getEffectiveLevel() == logging.DEBUG)
}
}
self.kwargs = recursive_update(deepcopy(self.kwargs),
self.override_scipy or {})
self.log.debug(
"Arguments for scipy.optimize.minimize:\n%r",
{k: v
for k, v in self.kwargs.items() if k != "fun"})
else:
methods = ["bobyqa", "scipy"]
raise LoggedError(self.log,
"Method '%s' not recognized. Try one of %r.",
self.method, methods)
def process_results(self):
"""
Determines success (or not), chooses best (if MPI)
and produces output (if requested).
"""
evals_attr_ = evals_attr[self.method.lower()]
# If something failed
if not hasattr(self, "result"):
return
if more_than_one_process():
results = get_mpi_comm().gather(self.result, root=0)
successes = get_mpi_comm().gather(self.success, root=0)
_affine_transform_baselines = get_mpi_comm().gather(
self._affine_transform_baseline, root=0)
if is_main_process():
mins = [(getattr(r, evals_attr_) if s else np.inf)
for r, s in zip(results, successes)]
i_min = np.argmin(mins)
self.result = results[i_min]
self._affine_transform_baseline = _affine_transform_baselines[
i_min]
else:
successes = [self.success]
if is_main_process():
if not any(successes):
raise LoggedError(
self.log,
"Minimization failed! Here is the raw result object:\n%s",
str(self.result))
elif not all(successes):
self.log.warning('Some minimizations failed!')
elif more_than_one_process():
if max(mins) - min(mins) > 1:
self.log.warning('Big spread in minima: %r', mins)
elif max(mins) - min(mins) > 0.2:
self.log.warning('Modest spread in minima: %r', mins)
logp_min = -np.array(getattr(self.result, evals_attr_))
x_min = self.inv_affine_transform(self.result.x)
self.log.info("-log(%s) minimized to %g",
"likelihood" if self.ignore_prior else "posterior",
-logp_min)
recomputed_post_min = self.model.logposterior(x_min, cached=False)
recomputed_logp_min = (sum(recomputed_post_min.loglikes)
if self.ignore_prior else
recomputed_post_min.logpost)
if not np.allclose(logp_min, recomputed_logp_min, atol=1e-2):
raise LoggedError(
self.log,
"Cannot reproduce log minimum to within 0.01. Maybe your "
"likelihood is stochastic or large numerical error? "
"Recomputed min: %g (was %g) at %r", recomputed_logp_min,
logp_min, x_min)
self.minimum = OnePoint(self.model,
self.output,
name="",
extension=get_collection_extension(
self.ignore_prior))
self.minimum.add(x_min,
derived=recomputed_post_min.derived,
logpost=recomputed_post_min.logpost,
logpriors=recomputed_post_min.logpriors,
loglikes=recomputed_post_min.loglikes)
self.log.info("Parameter values at minimum:\n%s",
self.minimum.data.to_string())
self.minimum.out_update()
self.dump_getdist()
def run(self):
"""
Runs the sampler.
"""
# Get first point, to be discarded -- not possible to determine its weight
# Still, we need to compute derived parameters, since, as the proposal "blocked",
# we may be saving the initial state of some block.
# NB: if resuming but nothing was written (burn-in not finished): re-start
self.log.info("Initial point:")
if self.resuming and self.collection.n():
initial_point = (self.collection[
self.collection.sampled_params].ix[self.collection.n() -
1]).values.copy()
logpost = -(self.collection[_minuslogpost].ix[self.collection.n() -
1].copy())
logpriors = -(self.collection[self.collection.prior_names].ix[
self.collection.n() - 1].copy())
loglikes = -0.5 * (self.collection[self.collection.chi2_names].ix[
self.collection.n() - 1].copy())
derived = (self.collection[self.collection.derived_params].ix[
self.collection.n() - 1].values.copy())
else:
initial_point = self.model.prior.reference(
max_tries=self.max_tries)
logpost, logpriors, loglikes, derived = self.model.logposterior(
initial_point)
self.current_point.add(initial_point,
derived=derived,
logpost=logpost,
logpriors=logpriors,
loglikes=loglikes)
self.log.info(
"\n%s",
self.current_point.data.to_string(index=False,
line_width=_line_width))
# Initial dummy checkpoint (needed when 1st checkpoint not reached in prev. run)
self.write_checkpoint()
# Main loop!
self.log.info("Sampling!" + (
" (NB: nothing will be printed until %d burn-in samples " %
self.burn_in + "have been obtained)" if self.burn_in else ""))
while self.n() < self.effective_max_samples and not self.converged:
self.get_new_sample()
# Callback function
if (hasattr(self, "callback_function_callable")
and not (max(self.n(), 1) % self.callback_every)
and self.current_point[_weight] == 1):
self.callback_function_callable(self)
self.last_point_callback = self.collection.n()
# Checking convergence and (optionally) learning the covmat of the proposal
if self.check_all_ready():
self.check_convergence_and_learn_proposal()
if self.n() == self.effective_max_samples:
self.log.info(
"Reached maximum number of accepted steps allowed. "
"Stopping.")
# Make sure the last batch of samples ( < output_every ) are written
self.collection._out_update()
if more_than_one_process():
Ns = (lambda x: np.array(get_mpi_comm().gather(x)))(self.n())
else:
Ns = [self.n()]
if am_single_or_primary_process():
self.log.info("Sampling complete after %d accepted steps.",
sum(Ns))
def check_convergence_and_learn_proposal(self):
"""
Checks the convergence of the sampling process (MPI only), and, if requested,
learns a new covariance matrix for the proposal distribution from the covariance
of the last samples.
"""
if more_than_one_process():
# Compute and gather means, covs and CL intervals of last half of chains
mean = self.collection.mean(first=int(self.n() / 2))
cov = self.collection.cov(first=int(self.n() / 2))
mcsamples = self.collection._sampled_to_getdist_mcsamples(
first=int(self.n() / 2))
try:
bound = np.array([[
mcsamples.confidence(i,
limfrac=self.Rminus1_cl_level / 2.,
upper=which)
for i in range(self.model.prior.d())
] for which in [False, True]]).T
success_bounds = True
except:
bound = None
success_bounds = False
Ns, means, covs, bounds = map(
lambda x: np.array(get_mpi_comm().gather(x)),
[self.n(), mean, cov, bound])
else:
# Compute and gather means, covs and CL intervals of last m-1 chain fractions
m = 1 + self.Rminus1_single_split
cut = int(self.collection.n() / m)
if cut <= 1:
self.log.error(
"Not enough points in chain to check convergence. "
"Increase `check_every` or reduce `Rminus1_single_split`.")
raise HandledException
Ns = (m - 1) * [cut]
means = np.array([
self.collection.mean(first=i * cut, last=(i + 1) * cut - 1)
for i in range(1, m)
])
covs = np.array([
self.collection.cov(first=i * cut, last=(i + 1) * cut - 1)
for i in range(1, m)
])
# No logging of warnings temporarily, so getdist won't complain unnecessarily
logging.disable(logging.WARNING)
mcsampleses = [
self.collection._sampled_to_getdist_mcsamples(
first=i * cut, last=(i + 1) * cut - 1)
for i in range(1, m)
]
logging.disable(logging.NOTSET)
try:
bounds = [
np.array([[
mcs.confidence(i,
limfrac=self.Rminus1_cl_level / 2.,
upper=which)
for i in range(self.model.prior.d())
] for which in [False, True]]).T for mcs in mcsampleses
]
success_bounds = True
except:
bounds = None
success_bounds = False
# Compute convergence diagnostics
if am_single_or_primary_process():
# "Within" or "W" term -- our "units" for assessing convergence
# and our prospective new covariance matrix
mean_of_covs = np.average(covs, weights=Ns, axis=0)
# "Between" or "B" term
# We don't weight with the number of samples in the chains here:
# shorter chains will likely be outliers, and we want to notice them
cov_of_means = np.atleast_2d(np.cov(means.T)) # , fweights=Ns)
# For numerical stability, we turn mean_of_covs into correlation matrix:
# rho = (diag(Sigma))^(-1/2) * Sigma * (diag(Sigma))^(-1/2)
# and apply the same transformation to the mean of covs (same eigenvals!)
diagSinvsqrt = np.diag(np.power(np.diag(cov_of_means), -0.5))
corr_of_means = diagSinvsqrt.dot(cov_of_means).dot(diagSinvsqrt)
norm_mean_of_covs = diagSinvsqrt.dot(mean_of_covs).dot(
diagSinvsqrt)
# Cholesky of (normalized) mean of covs and eigvals of Linv*cov_of_means*L
try:
L = np.linalg.cholesky(norm_mean_of_covs)
except np.linalg.LinAlgError:
self.log.warning(
"Negative covariance eigenvectors. "
"This may mean that the covariance of the samples does not "
"contain enough information at this point. "
"Skipping this checkpoint")
success = False
else:
Linv = np.linalg.inv(L)
try:
eigvals = np.linalg.eigvalsh(
Linv.dot(corr_of_means).dot(Linv.T))
success = True
except np.linalg.LinAlgError:
self.log.warning("Could not compute eigenvalues. "
"Skipping this checkpoint.")
success = False
if success:
Rminus1 = max(np.abs(eigvals))
# For real square matrices, a possible def of the cond number is:
condition_number = Rminus1 / min(np.abs(eigvals))
self.log.debug("Condition number = %g", condition_number)
self.log.debug("Eigenvalues = %r", eigvals)
self.log.info(
"Convergence of means: R-1 = %f after %d accepted steps"
%
(Rminus1,
(sum(Ns) if more_than_one_process() else self.n())) +
(" = sum(%r)" %
list(Ns) if more_than_one_process() else ""))
# Have we converged in means?
# (criterion must be fulfilled twice in a row)
if max(Rminus1, self.Rminus1_last) < self.Rminus1_stop:
# Check the convergence of the bounds of the confidence intervals
# Same as R-1, but with the rms deviation from the mean bound
# in units of the mean standard deviation of the chains
if success_bounds:
Rminus1_cl = (np.std(bounds, axis=0).T /
np.sqrt(np.diag(mean_of_covs)))
self.log.debug("normalized std's of bounds = %r",
Rminus1_cl)
self.log.info(
"Convergence of bounds: R-1 = %f after %d " %
(np.max(Rminus1_cl),
(sum(Ns) if more_than_one_process() else self.
n())) + "accepted steps" +
(" = sum(%r)" %
list(Ns) if more_than_one_process() else ""))
if np.max(Rminus1_cl) < self.Rminus1_cl_stop:
self.converged = True
self.log.info("The run has converged!")
self._Ns = Ns
else:
self.log.info(
"Computation of the bounds was not possible. "
"Waiting until the next checkpoint")
if more_than_one_process():
# Broadcast and save the convergence status and the last R-1 of means
success = get_mpi_comm().bcast(
(success if am_single_or_primary_process() else None), root=0)
if success:
self.Rminus1_last = get_mpi_comm().bcast(
(Rminus1 if am_single_or_primary_process() else None),
root=0)
self.converged = get_mpi_comm().bcast(
(self.converged
if am_single_or_primary_process() else None),
root=0)
else:
if success:
self.Rminus1_last = Rminus1
# Do we want to learn a better proposal pdf?
if self.learn_proposal and not self.converged and success:
good_Rminus1 = (self.learn_proposal_Rminus1_max > self.Rminus1_last
> self.learn_proposal_Rminus1_min)
if not good_Rminus1:
if am_single_or_primary_process():
self.log.info("Bad convergence statistics: "
"waiting until the next checkpoint.")
return
if more_than_one_process():
if not am_single_or_primary_process():
mean_of_covs = np.empty(
(self.model.prior.d(), self.model.prior.d()))
get_mpi_comm().Bcast(mean_of_covs, root=0)
else:
mean_of_covs = covs[0]
try:
self.proposer.set_covariance(mean_of_covs)
except:
self.log.debug(
"Updating covariance matrix failed unexpectedly. "
"waiting until next checkpoint.")
if am_single_or_primary_process():
self.log.info("Updated covariance matrix of proposal pdf.")
self.log.debug("%r", mean_of_covs)
# Save checkpoint info
self.write_checkpoint()
@pytest.fixture
def skip_not_installed(request):
return request.config.getoption("--skip-not-installed")
def install_test_wrapper(skip_not_installed, func, *args, **kwargs):
try:
return func(*args, **kwargs)
except NotInstalledError:
if skip_not_installed:
pytest.xfail("Missing dependencies.")
raise
if mpi.more_than_one_process():
@pytest.fixture(scope="session", autouse=True)
def mpi_handling(request):
mpi.capture_manager = request.config.pluginmanager.getplugin("capturemanager")
@pytest.hookimpl(hookwrapper=True)
def pytest_runtest_makereport(item, call):
outcome = yield
rep = outcome.get_result()
if rep.when == "call" and rep.failed:
rep.sections = [i for i in rep.sections if i[0] != "Captured log call"]
if call.excinfo and isinstance(call.excinfo.value, mpi.OtherProcessError):
# Only need very short message; stdout printed in raised-error process
rep.longrepr = str(call.excinfo.value)
rep.sections = []
def initialize(self):
"""Initializes the sampler:
creates the proposal distribution and draws the initial sample."""
if not self.model.prior.d():
raise LoggedError(self.log,
"No parameters being varied for sampler")
self.log.debug("Initializing")
# MARKED FOR DEPRECATION IN v3.0
if getattr(self, "oversample", None) is not None:
self.log.warning(
"*DEPRECATION*: `oversample` will be deprecated in the "
"next version. Oversampling is now requested by setting "
"`oversample_power` > 0.")
# END OF DEPRECATION BLOCK
# MARKED FOR DEPRECATION IN v3.0
if getattr(self, "check_every", None) is not None:
self.log.warning(
"*DEPRECATION*: `check_every` will be deprecated in the "
"next version. Please use `learn_every` instead.")
# BEHAVIOUR TO BE REPLACED BY ERROR:
self.learn_every = getattr(self, "check_every")
# END OF DEPRECATION BLOCK
if self.callback_every is None:
self.callback_every = self.learn_every
self._quants_d_units = []
for q in ["max_tries", "learn_every", "callback_every", "burn_in"]:
number = NumberWithUnits(getattr(self, q), "d", dtype=int)
self._quants_d_units.append(number)
setattr(self, q, number)
self.output_every = NumberWithUnits(self.output_every, "s", dtype=int)
if is_main_process():
if self.output.is_resuming() and (max(self.mpi_size or 0, 1) !=
max(get_mpi_size(), 1)):
raise LoggedError(
self.log,
"Cannot resume a run with a different number of chains: "
"was %d and now is %d.", max(self.mpi_size, 1),
max(get_mpi_size(), 1))
if more_than_one_process():
if get_mpi().Get_version()[0] < 3:
raise LoggedError(
self.log, "MPI use requires MPI version 3.0 or "
"higher to support IALLGATHER.")
sync_processes()
# One collection per MPI process: `name` is the MPI rank + 1
name = str(1 + (lambda r: r if r is not None else 0)(get_mpi_rank()))
self.collection = Collection(self.model,
self.output,
name=name,
resuming=self.output.is_resuming())
self.current_point = OneSamplePoint(self.model)
# Use standard MH steps by default
self.get_new_sample = self.get_new_sample_metropolis
# Prepare callback function
if self.callback_function is not None:
self.callback_function_callable = (get_external_function(
self.callback_function))
# Useful for getting last points added inside callback function
self.last_point_callback = 0
# Monitoring/restore progress
if is_main_process():
cols = [
"N", "timestamp", "acceptance_rate", "Rminus1", "Rminus1_cl"
]
self.progress = DataFrame(columns=cols)
self.i_learn = 1
if self.output and not self.output.is_resuming():
with open(self.progress_filename(), "w",
encoding="utf-8") as progress_file:
progress_file.write("# " +
" ".join(self.progress.columns) + "\n")
# Get first point, to be discarded -- not possible to determine its weight
# Still, we need to compute derived parameters, since, as the proposal "blocked",
# we may be saving the initial state of some block.
# NB: if resuming but nothing was written (burn-in not finished): re-start
if self.output.is_resuming() and len(self.collection):
initial_point = (self.collection[
self.collection.sampled_params].iloc[len(self.collection) -
1]).values.copy()
logpost = -(self.collection[_minuslogpost].iloc[
len(self.collection) - 1].copy())
logpriors = -(self.collection[self.collection.minuslogprior_names].
iloc[len(self.collection) - 1].copy())
loglikes = -0.5 * (self.collection[self.collection.chi2_names].
iloc[len(self.collection) - 1].copy())
derived = (self.collection[self.collection.derived_params].iloc[
len(self.collection) - 1].values.copy())
else:
# NB: max_tries adjusted to dim instead of #cycles (blocking not computed yet)
self.max_tries.set_scale(self.model.prior.d())
self.log.info(
"Getting initial point... (this may take a few seconds)")
initial_point, logpost, logpriors, loglikes, derived = \
self.model.get_valid_point(max_tries=self.max_tries.value)
# If resuming but no existing chain, assume failed run and ignore blocking
# if speeds measurement requested
if self.output.is_resuming() and not len(self.collection) \
and self.measure_speeds:
self.blocking = None
if self.measure_speeds and self.blocking:
self.log.warning(
"Parameter blocking manually fixed: speeds will not be measured."
)
elif self.measure_speeds:
n = None if self.measure_speeds is True else int(
self.measure_speeds)
self.model.measure_and_set_speeds(n=n, discard=0)
self.set_proposer_blocking()
self.set_proposer_covmat(load=True)
self.current_point.add(initial_point,
derived=derived,
logpost=logpost,
logpriors=logpriors,
loglikes=loglikes)
self.log.info("Initial point: %s", self.current_point)
# Max #(learn+convergence checks) to wait,
# in case one process dies without sending MPI_ABORT
self.been_waiting = 0
self.max_waiting = max(50, self.max_tries.unit_value)
# Burning-in countdown -- the +1 accounts for the initial point (always accepted)
self.burn_in_left = self.burn_in.value * self.current_point.output_thin + 1
# Initial dummy checkpoint
# (needed when 1st "learn point" not reached in prev. run)
self.write_checkpoint()
def initialize(self):
"""Imports the PolyChord sampler and prepares its arguments."""
if am_single_or_primary_process(
): # rank = 0 (MPI master) or None (no MPI)
self.log.info("Initializing")
# If path not given, try using general path to modules
if not self.path and self.path_install:
self.path = get_path(self.path_install)
if self.path:
if am_single_or_primary_process():
self.log.info("Importing *local* PolyChord from " + self.path)
if not os.path.exists(os.path.realpath(self.path)):
raise LoggedError(
self.log, "The given path does not exist. "
"Try installing PolyChord with "
"'cobaya-install polychord -m [modules_path]")
pc_build_path = get_build_path(self.path)
if not pc_build_path:
raise LoggedError(
self.log, "Either PolyChord is not in the given folder, "
"'%s', or you have not compiled it.", self.path)
# Inserting the previously found path into the list of import folders
sys.path.insert(0, pc_build_path)
else:
self.log.info("Importing *global* PolyChord.")
try:
import pypolychord
from pypolychord.settings import PolyChordSettings
self.pc = pypolychord
except ImportError:
raise LoggedError(
self.log, "Couldn't find the PolyChord python interface. "
"Make sure that you have compiled it, and that you either\n"
" (a) specify a path (you didn't) or\n"
" (b) install the Python interface globally with\n"
" '/path/to/PolyChord/python setup.py install --user'")
# Prepare arguments and settings
self.nDims = self.model.prior.d()
self.nDerived = (len(self.model.parameterization.derived_params()) +
len(self.model.prior) +
len(self.model.likelihood._likelihoods))
if self.logzero is None:
self.logzero = np.nan_to_num(-np.inf)
if self.max_ndead == np.inf:
self.max_ndead = -1
for p in ["nlive", "nprior", "max_ndead"]:
setattr(self, p,
read_dnumber(getattr(self, p), self.nDims, dtype=int))
# Fill the automatic ones
if getattr(self, "feedback", None) is None:
values = {
logging.CRITICAL: 0,
logging.ERROR: 0,
logging.WARNING: 0,
logging.INFO: 1,
logging.DEBUG: 2
}
self.feedback = values[self.log.getEffectiveLevel()]
try:
output_folder = getattr(self.output, "folder")
output_prefix = getattr(self.output, "prefix") or ""
self.read_resume = self.resuming
except AttributeError:
# dummy output -- no resume!
self.read_resume = False
from tempfile import gettempdir
output_folder = gettempdir()
if am_single_or_primary_process():
from random import random
output_prefix = hex(int(random() * 16**6))[2:]
else:
output_prefix = None
if more_than_one_process():
output_prefix = get_mpi_comm().bcast(output_prefix, root=0)
self.base_dir = os.path.join(output_folder, self.base_dir)
self.file_root = output_prefix
if am_single_or_primary_process():
# Creating output folder, if it does not exist (just one process)
if not os.path.exists(self.base_dir):
os.makedirs(self.base_dir)
# Idem, a clusters folder if needed -- notice that PolyChord's default
# is "True", here "None", hence the funny condition below
if self.do_clustering is not False: # None here means "default"
try:
os.makedirs(os.path.join(self.base_dir, clusters))
except OSError: # exists!
pass
self.log.info("Storing raw PolyChord output in '%s'.",
self.base_dir)
# Exploiting the speed hierarchy
if self.blocking:
speeds, blocks = self.model.likelihood._check_speeds_of_params(
self.blocking)
else:
speeds, blocks = self.model.likelihood._speeds_of_params(
int_speeds=True)
blocks_flat = list(chain(*blocks))
self.ordering = [
blocks_flat.index(p)
for p in self.model.parameterization.sampled_params()
]
self.grade_dims = np.array([len(block) for block in blocks])
# bugfix: pypolychord's C interface for Fortran does not like int numpy types
self.grade_dims = [int(x) for x in self.grade_dims]
# Steps per block
# NB: num_repeats is ignored by PolyChord when int "grade_frac" given,
# so needs to be applied by hand.
# Make sure that speeds are integer, and that the slowest is 1,
# for a straightforward application of num_repeats
speeds = relative_to_int(speeds, 1)
# In num_repeats, `d` is interpreted as dimension of each block
self.grade_frac = [
int(speed * read_dnumber(self.num_repeats, dim_block))
for speed, dim_block in zip(speeds, self.grade_dims)
]
# Assign settings
pc_args = [
"nlive", "num_repeats", "nprior", "do_clustering",
"precision_criterion", "max_ndead", "boost_posterior", "feedback",
"logzero", "posteriors", "equals", "compression_factor",
"cluster_posteriors", "write_resume", "read_resume", "write_stats",
"write_live", "write_dead", "base_dir", "grade_frac", "grade_dims",
"feedback", "read_resume", "base_dir", "file_root", "grade_frac",
"grade_dims"
]
# As stated above, num_repeats is ignored, so let's not pass it
pc_args.pop(pc_args.index("num_repeats"))
self.pc_settings = PolyChordSettings(
self.nDims,
self.nDerived,
seed=(self.seed if self.seed is not None else -1),
**{
p: getattr(self, p)
for p in pc_args if getattr(self, p) is not None
})
# prior conversion from the hypercube
bounds = self.model.prior.bounds(
confidence_for_unbounded=self.confidence_for_unbounded)
# Check if priors are bounded (nan's to inf)
inf = np.where(np.isinf(bounds))
if len(inf[0]):
params_names = self.model.parameterization.sampled_params()
params = [params_names[i] for i in sorted(list(set(inf[0])))]
raise LoggedError(
self.log,
"PolyChord needs bounded priors, but the parameter(s) '"
"', '".join(params) + "' is(are) unbounded.")
locs = bounds[:, 0]
scales = bounds[:, 1] - bounds[:, 0]
# This function re-scales the parameters AND puts them in the right order
self.pc_prior = lambda x: (locs + np.array(x)[self.ordering] * scales
).tolist()
# We will need the volume of the prior domain, since PolyChord divides by it
self.logvolume = np.log(np.prod(scales))
# Prepare callback function
if self.callback_function is not None:
self.callback_function_callable = (get_external_function(
self.callback_function))
self.last_point_callback = 0
# Prepare runtime live and dead points collections
self.live = Collection(self.model,
None,
name="live",
initial_size=self.pc_settings.nlive)
self.dead = Collection(self.model, self.output, name="dead")
self.n_sampled = len(self.model.parameterization.sampled_params())
self.n_derived = len(self.model.parameterization.derived_params())
self.n_priors = len(self.model.prior)
self.n_likes = len(self.model.likelihood._likelihoods)
# Done!
if am_single_or_primary_process():
self.log.info("Calling PolyChord with arguments:")
for p, v in inspect.getmembers(self.pc_settings,
lambda a: not (callable(a))):
if not p.startswith("_"):
self.log.info(" %s: %s", p, v)
def set_resuming(self, *args, **kwargs):
if is_main_process():
Output.set_resuming(self, *args, **kwargs)
if more_than_one_process():
self._resuming = share_mpi(
self._resuming if is_main_process() else None)
def initialize(self):
if self.method not in evals_attr:
raise LoggedError(self.log, "Method '%s' not recognized. Try one of %r.",
self.method, list(evals_attr))
self.mpi_info("Initializing")
self.max_iter = int(read_dnumber(self.max_evals, self.model.prior.d()))
# Configure target
method = self.model.loglike if self.ignore_prior else self.model.logpost
kwargs = {"make_finite": True}
if self.ignore_prior:
kwargs["return_derived"] = False
self.logp = lambda x: method(x, **kwargs)
# Try to load info from previous samples.
# If none, sample from reference (make sure that it has finite like/post)
self.initial_points = []
assert self.best_of > 0
num_starts = int(np.ceil(self.best_of / mpi.size()))
if self.output:
files = self.output.find_collections()
else:
files = None
for start in range(num_starts):
initial_point = None
if files:
collection_in: Optional[SampleCollection]
if mpi.more_than_one_process() or num_starts > 1:
index = 1 + mpi.rank() * num_starts + start
if index <= len(files):
collection_in = SampleCollection(
self.model, self.output, name=str(index), resuming=True)
else:
collection_in = None
else:
collection_in = self.output.load_collections(self.model,
concatenate=True)
if collection_in:
initial_point = (collection_in.bestfit() if self.ignore_prior
else collection_in.MAP())
initial_point = initial_point[
list(self.model.parameterization.sampled_params())].values
self.log.info("Starting %s/%s from %s of previous chain:", start + 1,
num_starts, "best fit" if self.ignore_prior else "MAP")
# Compute covmat if input but no .covmat file (e.g. with PolyChord)
# Prefer old over `covmat` definition in yaml (same as MCMC)
self.covmat = collection_in.cov(derived=False)
self.covmat_params = list(
self.model.parameterization.sampled_params())
if initial_point is None:
for _ in range(self.max_iter // 10 + 5):
initial_point = self.model.prior.reference(random_state=self._rng)
if np.isfinite(self.logp(initial_point)):
break
else:
raise LoggedError(self.log, "Could not find random starting point "
"giving finite posterior")
self.log.info("Starting %s/%s random initial point:",
start + 1, num_starts)
self.log.info(
dict(zip(self.model.parameterization.sampled_params(), initial_point)))
self.initial_points.append(initial_point)
self._bounds = self.model.prior.bounds(
confidence_for_unbounded=self.confidence_for_unbounded)
# TODO: if ignore_prior, one should use *like* covariance (this is *post*)
covmat = self._load_covmat(prefer_load_old=self.output)[0]
# scale by conditional parameter widths (since not using correlation structure)
scales = np.minimum(1 / np.sqrt(np.diag(np.linalg.inv(covmat))),
(self._bounds[:, 1] - self._bounds[:, 0]) / 3)
# Cov and affine transformation
# Transform to space where initial point is at centre, and cov is normalised
# Cannot do rotation, as supported minimization routines assume bounds aligned
# with the parameter axes.
self._affine_transform_matrix = np.diag(1 / scales)
self._inv_affine_transform_matrix = np.diag(scales)
self._scales = scales
self.result = None
