def newton_call(self):
        """
        Function calls for Newton power flow

        Returns
        -------
        None

        """
        # system = self.system
        # exec(system.call.newton)

        system = self.system
        dae = self.system.dae

        system.dae.init_fg()
        system.dae.reset_small_g()
        # evaluate algebraic equation mismatches
        for model, pflow, gcall in zip(system.devman.devices,
                                       system.call.pflow, system.call.gcall):
            if pflow and gcall:
                system.__dict__[model].gcall(dae)

        # eval differential equations
        for model, pflow, fcall in zip(system.devman.devices,
                                       system.call.pflow, system.call.fcall):
            if pflow and fcall:
                system.__dict__[model].fcall(dae)

        # reset islanded buses mismatches
        system.Bus.gisland(dae)

        if system.dae.factorize:
            system.dae.init_jac0()
            # evaluate constant Jacobian elements
            for model, pflow, jac0 in zip(system.devman.devices,
                                          system.call.pflow, system.call.jac0):
                if pflow and jac0:
                    system.__dict__[model].jac0(dae)
            dae.temp_to_spmatrix('jac0')

        dae.setup_FxGy()

        # evaluate Gy
        for model, pflow, gycall in zip(system.devman.devices,
                                        system.call.pflow, system.call.gycall):
            if pflow and gycall:
                system.__dict__[model].gycall(dae)

        # evaluate Fx
        for model, pflow, fxcall in zip(system.devman.devices,
                                        system.call.pflow, system.call.fxcall):
            if pflow and fxcall:
                system.__dict__[model].fxcall(dae)

        # reset islanded buses Jacobians
        system.Bus.gyisland(dae)

        dae.temp_to_spmatrix('jac')
Function calls for Newton power flow

        Returns
        -------
        None