def __math_on_stack(self, used_lock=False):
<EOL>self.__get_sigmas()<EOL>self.__update_layer_density()<EOL>self.__calculate_atoms_per_cm3(used_lock=used_lock)<EOL>self.__calculate_transmission_attenuation()<EOL>
will perform all the various update of the stack, such as populating the stack_sigma, caluclate the density of the
        layers....etc.