增加注释

rspower/lib/newtonpf.txt

@@ -45,6 +45,8 @@ fn newtonpf(Ybus, Sbus, V0, ref, pv, pq, mpopt) {
     V = V0;
     Va = angle(V);
     Vm = abs(V);
+
+    // set up indexing for updating V
     nb = length(V);
     npv = length(pv);
     npq = length(pq);
@@ -52,16 +54,19 @@ fn newtonpf(Ybus, Sbus, V0, ref, pv, pq, mpopt) {
     j3 = j2;    j4 = j2 + npq;      // j3:j4 - V angle of pq buses
     j5 = j4;    j6 = j4 + npq;      // j5:j6 - V mag of pq buses
     pv_pq_i = horzcat(pv, pq);
+
     // evaluate F(x0)
     mis = V .* conj(Ybus * V) - Sbus;
     F = vertcat(real(get_multi(mis, pv_pq_i))', imag(get_multi(mis, pq))');
+
     // check tolerance
     normF = norm_max(F);
+
     // do Newton iterations
     while ~~converged && i < max_it {
         // update iteration counter
         i = i + 1;
-        // evaluate Jacobian
+        // evaluate Jacobian 因迭代中V变化，因此jac需要从dSbus_dV重新计算
         jac = dSbus_dV(Ybus, V, 0);
         dSbus_dVa = slice(jac, [0], [0,nb]);
         dSbus_dVm = slice(jac, [0], [nb,2*nb]);