    def _init_arrays(self, size=0):
        if self.initialized:
            self._cluster_hits = np.zeros(shape=(size, ), dtype=np.dtype(self._cluster_hits_descr))
            self._clusters = np.zeros(shape=(size, ), dtype=np.dtype(self._cluster_descr))
            self._assigned_hit_array = np.zeros(shape=(size, ), dtype=np.bool)
            self._cluster_hit_indices = np.empty(shape=(size, ), dtype=np_int_type_chooser(size))
            self._cluster_hit_indices.fill(-1)