Source code for b2pandas_utils

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# basf2 (Belle II Analysis Software Framework)                           #
# Author: The Belle II Collaboration                                     #
#                                                                        #
# See git log for contributors and copyright holders.                    #
# This file is licensed under LGPL-3.0, see LICENSE.md.                  #
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import basf2
import variables
import tables
import numpy as np
import warnings


"""
Python utilities to help create or manage ntuples and work with them in pandas
"""


[docs] class VariablesToHDF5(basf2.Module): """ Dump variables directly to HDF5 This Module is the equivalent of VariablesToNtuple but creates an hdf5 file instead of a root file. It is slower as it is implemented in pure python and should currently be considered a proof of concept. """ def __init__(self, listname, variables, filename): """Constructor to initialize the internal state Arguments: listname(str): name of the particle list variables(list(str)): list of variables to save for each particle filename(str): name of the hdf5 file to be created """ super().__init__() #: Output filename self._filename = filename #: Particle list name self._listname = listname #: List of variables self._variables = variables
[docs] def initialize(self): """Create the hdf5 file and list of variable objects to be used during event processing.""" # Always avoid the top-level 'import ROOT'. import ROOT # noqa #: variable names self._varnames = [ str(varname) for varname in variables.variables.resolveCollections( variables.std_vector( *self._variables))] #: variable objects for each variable self._var_objects = [variables.variables.getVariable(n) for n in self._varnames] #: Event metadata self._evtmeta = ROOT.Belle2.PyStoreObj("EventMetaData") self._evtmeta.isRequired() #: Pointer to the particle list self._plist = ROOT.Belle2.PyStoreObj(self._listname) self._plist.isRequired() #: The hdf5 file self._hdf5file = tables.open_file(self._filename, mode="w", title="Belle2 Variables to HDF5") if not self._hdf5file: basf2.B2ERROR("Cannot create output file") return dtype = [("exp", np.int32), ("run", np.int32), ("evt", np.uint32), ("prod", np.uint32), ("icand", np.uint32), ("ncand", np.uint32)] for name in self._varnames: # only float variables for now dtype.append((name, np.float64)) #: The data type self._dtype = dtype filters = tables.Filters(complevel=1, complib='blosc:lz4', fletcher32=False) # some variable names are not just A-Za-z0-9 so pytables complains but # seems to work. Ignore warning with warnings.catch_warnings(): warnings.simplefilter("ignore") #: The pytable self._table = self._hdf5file.create_table("/", self._listname, obj=np.zeros(0, dtype), filters=filters)
[docs] def event(self): """Create a new row in the hdf5 file with for each particle in the list""" buf = np.empty(self._plist.getListSize(), dtype=self._dtype) # add some extra columns for bookkeeping buf["exp"] = self._evtmeta.getExperiment() buf["run"] = self._evtmeta.getRun() buf["evt"] = self._evtmeta.getEvent() buf["prod"] = self._evtmeta.getProduction() buf["ncand"] = len(buf) buf["icand"] = np.arange(len(buf)) for row, p in zip(buf, self._plist): for name, v in zip(self._varnames, self._var_objects): # pyroot proxy not working with callables, we should fix this. # For now we need to go back by name and call it. # should be `row[v.name] = v.func(p)` row[name] = variables.variables.evaluate(v.name, p) self._table.append(buf)
[docs] def terminate(self): """save and close the output""" self._table.flush() self._hdf5file.close() import ROOT ROOT.Belle2.MetadataService.Instance().addHDF5File(self._filename)
def make_mcerrors_readable(dataframe, column="mcErrors"): """ Take a dataframe containing an column with the output of the :b2:var:`mcErrors` variable from :b2:mod:`VariablesToNTuple` and convert it to a readable set of columns of the form ``{column}_{name}`` where column is the value of the ``column`` argument and ``name`` is one of one of the :ref:`mcmatching` error flags (without the leading 'c_'). Arguments: dataframe(pandas.DataFrame): the pandas dataframe containing an ntuple with column containing the output of the mcErrors variable column(str): the name containing the values from the mcErrors variable """ # Always avoid the top-level 'import ROOT'. import ROOT # noqa if column not in dataframe: raise KeyError(f"Cannot find column '{column}'") # convert mcErrors to int to be able to logical operate on it mcErrors = dataframe[column].astype(int) # and loop over all the c_ constants in the Belle2.MCMatching class for flag in (e for e in dir(ROOT.Belle2.MCMatching) if e.startswith("c_")): try: value = int(getattr(ROOT.Belle2.MCMatching, flag)) except ValueError: # probably the extraInfo column name, ignore continue # and set the column name = column + flag[1:] if value == 0: dataframe[name] = mcErrors == 0 else: dataframe[name] = (mcErrors & value) == value # This is just for testing, no need for doxygen to weirdly document it # @cond if __name__ == "__main__": import modularAnalysis p = basf2.create_path() p.add_module("EventInfoSetter", evtNumList=100) p.add_module("EvtGenInput") modularAnalysis.fillParticleListsFromMC([("pi-:gen", "")], path=p) a = VariablesToHDF5("pi-:gen", ["M", "E", "px", "py", "pz"], "test.hdf5") p.add_module(a) # Process the events basf2.process(p) print(basf2.statistics) # @endcond