def pop(self, dry_run=False, iteration=-1):
        """ """
        if self.is_finished_scf != True:
            self.calc_sp(dry_run)

        if iteration == -1:
            iteration = self.pdfparam.iterations

        self._calc_pop(iteration=iteration)
        pop_vtr = self.get_pop(iteration)

        self.save()
        self.restore_cwd()

        return pop_vtr