def test_sample_gmpe(self):
(value, weight, branch_ids) = logictree.sample_one(
self.gmpe_lt, self.rnd)
self.assertEqual(value,
{'Subduction Interface': 'SadighEtAl1997',
'Active Shallow Crust': 'ChiouYoungs2008'})
self.assertEqual(weight, 0.5)
self.assertEqual(('b2', 'b3'), branch_ids)
def initialize_realizations(self):
"""
Create records for the `hzrdr.lt_realization`.
This function works either in random sampling mode (when lt_realization
models get the random seed value) or in enumeration mode (when weight
values are populated). In both cases we record the logic tree paths
for both trees in the `lt_realization` record, as well as ordinal
number of the realization (zero-based).
"""
logs.LOG.progress("initializing realizations")
num_samples = self.hc.number_of_logic_tree_samples
gsim_lt_dict = {} # gsim_lt per source model logic tree path
for idx, (sm, weight, sm_lt_path) in enumerate(self.source_model_lt):
try:
lt_model = models.LtSourceModel.objects.get(
hazard_calculation=self.job, sm_lt_path=sm_lt_path)
except ObjectDoesNotExist:
# this happens if there are no sources for the source
# model at the given path
logs.LOG.warn('No sources for sm_lt_path %s', sm_lt_path)
continue
if not sm_lt_path in gsim_lt_dict:
gsim_lt_dict[sm_lt_path] = lt_model.make_gsim_lt()
gsim_lt = gsim_lt_dict[sm_lt_path]
if num_samples: # sampling, pick just one gsim realization
rnd = random.Random(self.hc.random_seed + idx)
rlzs = [logictree.sample_one(gsim_lt, rnd)]
else:
rlzs = list(gsim_lt) # full enumeration
logs.LOG.info('Creating %d GMPE realization(s) for model %s, %s',
len(rlzs), lt_model.sm_name, lt_model.sm_lt_path)
self._initialize_realizations(idx, lt_model, rlzs, gsim_lt)
num_ind_rlzs = sum(gsim_lt.get_num_paths()
for gsim_lt in gsim_lt_dict.itervalues())
if num_samples > num_ind_rlzs:
logs.LOG.warn("""
The number of independent realizations is %d but you are using %d samplings.
That means that some GMPEs will be sampled more than once, resulting in
duplicated data and redundant computation. You should switch to full
enumeration mode, i.e. set number_of_logic_tree_samples=0 in your .ini file.
""", num_ind_rlzs, num_samples)