def children_solve_nonlinear(self, metadata):

        # transfer data to each subsystem and then solve_nonlinear it
        for sub in itervalues(self._subsystems):
            self._transfer_data(sub.name)
            if sub.is_active():
                with sub._dircontext:
                    if isinstance(sub, Component):
                        sub.solve_nonlinear(sub.params, sub.unknowns, sub.resids)
                    else:
                        sub.solve_nonlinear(sub.params, sub.unknowns, sub.resids, metadata)
Loops over our children systems and asks them to solve.
dataset/ETHPy150Open OpenMDAO/OpenMDAO/openmdao/core/group.py/Group.children_solve_nonlinear