Example #1
0
 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)
Example #2
0
    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)