emptyrelations.py

#!/usr/bin/env python3
 

 
from basf2 import set_random_seed, create_path, Module
from ROOT import Belle2
from b2test_utils import safe_process, clean_working_directory
 
set_random_seed("something important")
 
 
class MakeRelations(Module):
    '''Simple module that creates some relations.'''
 
    def initialize(self):
        '''Initialize.'''
        
        self.tracks = Belle2.PyStoreArray('Tracks')
        
        self.clusters = Belle2.PyStoreArray('KLMClusters')
        self.tracks.registerInDataStore()
        self.clusters.registerInDataStore()
        self.tracks.registerRelationTo(self.clusters)
        
        self.first = True
 
    def event(self):
        '''Event.'''
        if not self.first:
            track = self.tracks.appendNew()
            cluster = self.clusters.appendNew()
            track.addRelationTo(cluster)
        self.first = False
 
 
def create_file():
    """Create file with empty first event"""
    path = create_path()
    path.add_module('EventInfoSetter')
    path.add_module(MakeRelations())
    path.add_module('RootOutput', outputFileName='test.root')
    safe_process(path, 2)
 
 
def read_file():
    """Read file with empty first event"""
    path = create_path()
    path.add_module('RootInput', inputFileName='test.root')
    path.add_module('PrintCollections', printForEvent=0)
    safe_process(path)
 
 
if __name__ == "__main__":
    with clean_working_directory():
        create_file()
        read_file()