code: def _update_solution_data(self, s):
          
          x = s["x"]
  #        Va_var = self.om.get_var("Va")
  #        Vm_var = self.om.get_var("Vm")
  #        Pg_var = self.om.get_var("Pg")
  #        Qg_var = self.om.get_var("Qg")
  
          Va = x[self._Va.i1:self._Va.iN + 1]
          Vm = x[self._Vm.i1:self._Vm.iN + 1]
          Pg = x[self._Pg.i1:self._Pg.iN + 1]
          Qg = x[self._Qg.i1:self._Qg.iN + 1]
  
  #        f = 0.5 * dot(x.T * HH, x) + dot(CC.T, x)
  
  #        s["f"] = s["f"] + C0
  
          # Put the objective function value in the solution.
  #        solution["f"] = f
  
          return Va, Vm, Pg, Qg
docs: Returns the voltage angle and generator set-point vectors.