Source code for pyhf.modifiers.shapesys

import logging

from . import modifier
from .. import get_backend, default_backend, events
from ..parameters import constrained_by_poisson, ParamViewer

log = logging.getLogger(__name__)


[docs]@modifier( name='shapesys', constrained=True, pdf_type='poisson', op_code='multiplication' ) class shapesys(object):
[docs] @classmethod def required_parset(cls, sample_data, modifier_data): # count the number of bins with nonzero, positive yields valid_bins = [ (sample_bin > 0 and modifier_bin > 0) for sample_bin, modifier_bin in zip(modifier_data, sample_data) ] n_parameters = sum(valid_bins) return { 'paramset_type': constrained_by_poisson, 'n_parameters': n_parameters, 'modifier': cls.__name__, 'is_constrained': cls.is_constrained, 'is_shared': False, 'inits': (1.0,) * n_parameters, 'bounds': ((1e-10, 10.0),) * n_parameters, 'fixed': False, # nb: auxdata/factors set by finalize. Set to non-numeric to crash # if we fail to set auxdata/factors correctly 'auxdata': (None,) * n_parameters, 'factors': (None,) * n_parameters, }
class shapesys_combined(object): def __init__(self, shapesys_mods, pdfconfig, mega_mods, batch_size=None): self.batch_size = batch_size keys = ['{}/{}'.format(mtype, m) for m, mtype in shapesys_mods] self._shapesys_mods = [m for m, _ in shapesys_mods] parfield_shape = (self.batch_size or 1, pdfconfig.npars) self.param_viewer = ParamViewer( parfield_shape, pdfconfig.par_map, self._shapesys_mods ) self._shapesys_mask = [ [[mega_mods[m][s]['data']['mask']] for s in pdfconfig.samples] for m in keys ] self.__shapesys_info = default_backend.astensor( [ [ [ mega_mods[m][s]['data']['mask'], mega_mods[m][s]['data']['nom_data'], mega_mods[m][s]['data']['uncrt'], ] for s in pdfconfig.samples ] for m in keys ] ) self.finalize(pdfconfig) global_concatenated_bin_indices = [ [[j for c in pdfconfig.channels for j in range(pdfconfig.channel_nbins[c])]] ] self._access_field = default_backend.tile( global_concatenated_bin_indices, (len(shapesys_mods), self.batch_size or 1, 1), ) # access field is shape (sys, batch, globalbin) # reindex it based on current masking self._reindex_access_field(pdfconfig) self._precompute() events.subscribe('tensorlib_changed')(self._precompute) def _reindex_access_field(self, pdfconfig): for syst_index, syst_access in enumerate(self._access_field): if not pdfconfig.param_set(self._shapesys_mods[syst_index]).n_parameters: self._access_field[syst_index] = 0 continue singular_sample_index = [ idx for idx, syst in enumerate( default_backend.astensor(self._shapesys_mask)[syst_index, :, 0] ) if any(syst) ][-1] for batch_index, batch_access in enumerate(syst_access): selection = self.param_viewer.index_selection[syst_index][batch_index] access_field_for_syst_and_batch = default_backend.zeros( len(batch_access) ) sample_mask = self._shapesys_mask[syst_index][singular_sample_index][0] access_field_for_syst_and_batch[sample_mask] = selection self._access_field[ syst_index, batch_index ] = access_field_for_syst_and_batch def _precompute(self): tensorlib, _ = get_backend() if not self.param_viewer.index_selection: return self.shapesys_mask = tensorlib.astensor(self._shapesys_mask, dtype="bool") self.shapesys_mask = tensorlib.tile( self.shapesys_mask, (1, 1, self.batch_size or 1, 1) ) self.access_field = tensorlib.astensor(self._access_field, dtype='int') self.sample_ones = tensorlib.ones(tensorlib.shape(self.shapesys_mask)[1]) self.shapesys_default = tensorlib.ones(tensorlib.shape(self.shapesys_mask)) def finalize(self, pdfconfig): # self.__shapesys_info: (parameter, sample, [mask, nominal rate, uncertainty], bin) for mod_uncert_info, pname in zip(self.__shapesys_info, self._shapesys_mods): # skip cases where given shapesys modifier affects zero samples if not pdfconfig.param_set(pname).n_parameters: continue # identify the information for the sample that the given parameter # affects. shapesys is not shared, so there should only ever be at # most one sample # sample_uncert_info: ([mask, nominal rate, uncertainty], bin) sample_uncert_info = mod_uncert_info[ default_backend.astensor( default_backend.sum(mod_uncert_info[:, 0] > 0, axis=1), dtype='bool' ) ][0] # bin_mask: ([mask], bin) bin_mask = default_backend.astensor(sample_uncert_info[0], dtype='bool') # nom_unc: ([nominal, uncertainty], bin) nom_unc = sample_uncert_info[1:] # compute gamma**2 and sigma**2 nom_unc_sq = default_backend.power(nom_unc, 2) # when the nominal rate = 0 OR uncertainty = 0, set = 1 nom_unc_sq[nom_unc_sq == 0] = 1 # divide (gamma**2 / sigma**2) and mask to set factors for only the # parameters we have allocated factors = (nom_unc_sq[0] / nom_unc_sq[1])[bin_mask] assert len(factors) == pdfconfig.param_set(pname).n_parameters pdfconfig.param_set(pname).factors = default_backend.tolist(factors) pdfconfig.param_set(pname).auxdata = default_backend.tolist(factors) def apply(self, pars): """ Returns: modification tensor: Shape (n_modifiers, n_global_samples, n_alphas, n_global_bin) """ tensorlib, _ = get_backend() if not self.param_viewer.index_selection: return tensorlib, _ = get_backend() if self.batch_size is None: flat_pars = pars else: flat_pars = tensorlib.reshape(pars, (-1,)) shapefactors = tensorlib.gather(flat_pars, self.access_field) results_shapesys = tensorlib.einsum( 'mab,s->msab', shapefactors, self.sample_ones ) results_shapesys = tensorlib.where( self.shapesys_mask, results_shapesys, self.shapesys_default ) return results_shapesys