Actual source code: ex9busoptfd.c

  1: static char help[] = "Using finite difference for the problem in ex9busopt.c \n\n";

  3: /*
  4:   Use finite difference approximations to solve the same optimization problem as in ex9busopt.c.
  5:  */

  7: #include <petsctao.h>
  8: #include <petscts.h>
  9: #include <petscdm.h>
 10: #include <petscdmda.h>
 11: #include <petscdmcomposite.h>

 13: PetscErrorCode FormFunction(Tao, Vec, PetscReal *, void *);

 15: #define freq 60
 16: #define w_s  (2 * PETSC_PI * freq)

 18: /* Sizes and indices */
 19: const PetscInt nbus    = 9;         /* Number of network buses */
 20: const PetscInt ngen    = 3;         /* Number of generators */
 21: const PetscInt nload   = 3;         /* Number of loads */
 22: const PetscInt gbus[3] = {0, 1, 2}; /* Buses at which generators are incident */
 23: const PetscInt lbus[3] = {4, 5, 7}; /* Buses at which loads are incident */

 25: /* Generator real and reactive powers (found via loadflow) */
 26: PetscScalar PG[3] = {0.69, 1.59, 0.69};
 27: /* PetscScalar PG[3] = {0.716786142395021,1.630000000000000,0.850000000000000};*/
 28: const PetscScalar QG[3] = {0.270702180178785, 0.066120127797275, -0.108402221791588};
 29: /* Generator constants */
 30: const PetscScalar H[3]    = {23.64, 6.4, 3.01};       /* Inertia constant */
 31: const PetscScalar Rs[3]   = {0.0, 0.0, 0.0};          /* Stator Resistance */
 32: const PetscScalar Xd[3]   = {0.146, 0.8958, 1.3125};  /* d-axis reactance */
 33: const PetscScalar Xdp[3]  = {0.0608, 0.1198, 0.1813}; /* d-axis transient reactance */
 34: const PetscScalar Xq[3]   = {0.4360, 0.8645, 1.2578}; /* q-axis reactance Xq(1) set to 0.4360, value given in text 0.0969 */
 35: const PetscScalar Xqp[3]  = {0.0969, 0.1969, 0.25};   /* q-axis transient reactance */
 36: const PetscScalar Td0p[3] = {8.96, 6.0, 5.89};        /* d-axis open circuit time constant */
 37: const PetscScalar Tq0p[3] = {0.31, 0.535, 0.6};       /* q-axis open circuit time constant */
 38: PetscScalar       M[3];                               /* M = 2*H/w_s */
 39: PetscScalar       D[3];                               /* D = 0.1*M */

 41: PetscScalar TM[3]; /* Mechanical Torque */
 42: /* Exciter system constants */
 43: const PetscScalar KA[3] = {20.0, 20.0, 20.0};    /* Voltage regulartor gain constant */
 44: const PetscScalar TA[3] = {0.2, 0.2, 0.2};       /* Voltage regulator time constant */
 45: const PetscScalar KE[3] = {1.0, 1.0, 1.0};       /* Exciter gain constant */
 46: const PetscScalar TE[3] = {0.314, 0.314, 0.314}; /* Exciter time constant */
 47: const PetscScalar KF[3] = {0.063, 0.063, 0.063}; /* Feedback stabilizer gain constant */
 48: const PetscScalar TF[3] = {0.35, 0.35, 0.35};    /* Feedback stabilizer time constant */
 49: const PetscScalar k1[3] = {0.0039, 0.0039, 0.0039};
 50: const PetscScalar k2[3] = {1.555, 1.555, 1.555}; /* k1 and k2 for calculating the saturation function SE = k1*exp(k2*Efd) */

 52: PetscScalar Vref[3];
 53: /* Load constants
 54:   We use a composite load model that describes the load and reactive powers at each time instant as follows
 55:   P(t) = \sum\limits_{i=0}^ld_nsegsp \ld_alphap_i*P_D0(\frac{V_m(t)}{V_m0})^\ld_betap_i
 56:   Q(t) = \sum\limits_{i=0}^ld_nsegsq \ld_alphaq_i*Q_D0(\frac{V_m(t)}{V_m0})^\ld_betaq_i
 57:   where
 58:     ld_nsegsp,ld_nsegsq - Number of individual load models for real and reactive power loads
 59:     ld_alphap,ld_alphap - Percentage contribution (weights) or loads
 60:     P_D0                - Real power load
 61:     Q_D0                - Reactive power load
 62:     V_m(t)              - Voltage magnitude at time t
 63:     V_m0                - Voltage magnitude at t = 0
 64:     ld_betap, ld_betaq  - exponents describing the load model for real and reactive part

 66:     Note: All loads have the same characteristic currently.
 67: */
 68: const PetscScalar PD0[3]       = {1.25, 0.9, 1.0};
 69: const PetscScalar QD0[3]       = {0.5, 0.3, 0.35};
 70: const PetscInt    ld_nsegsp[3] = {3, 3, 3};
 71: const PetscScalar ld_alphap[3] = {1.0, 0.0, 0.0};
 72: const PetscScalar ld_betap[3]  = {2.0, 1.0, 0.0};
 73: const PetscInt    ld_nsegsq[3] = {3, 3, 3};
 74: const PetscScalar ld_alphaq[3] = {1.0, 0.0, 0.0};
 75: const PetscScalar ld_betaq[3]  = {2.0, 1.0, 0.0};

 77: typedef struct {
 78:   DM          dmgen, dmnet;        /* DMs to manage generator and network subsystem */
 79:   DM          dmpgrid;             /* Composite DM to manage the entire power grid */
 80:   Mat         Ybus;                /* Network admittance matrix */
 81:   Vec         V0;                  /* Initial voltage vector (Power flow solution) */
 82:   PetscReal   tfaulton, tfaultoff; /* Fault on and off times */
 83:   PetscInt    faultbus;            /* Fault bus */
 84:   PetscScalar Rfault;
 85:   PetscReal   t0, tmax;
 86:   PetscInt    neqs_gen, neqs_net, neqs_pgrid;
 87:   Mat         Sol; /* Matrix to save solution at each time step */
 88:   PetscInt    stepnum;
 89:   PetscBool   alg_flg;
 90:   PetscReal   t;
 91:   IS          is_diff;        /* indices for differential equations */
 92:   IS          is_alg;         /* indices for algebraic equations */
 93:   PetscReal   freq_u, freq_l; /* upper and lower frequency limit */
 94:   PetscInt    pow;            /* power coefficient used in the cost function */
 95:   Vec         vec_q;
 96: } Userctx;

 98: /* Converts from machine frame (dq) to network (phase a real,imag) reference frame */
 99: PetscErrorCode dq2ri(PetscScalar Fd, PetscScalar Fq, PetscScalar delta, PetscScalar *Fr, PetscScalar *Fi)
100: {
101:   PetscFunctionBegin;
102:   *Fr = Fd * PetscSinScalar(delta) + Fq * PetscCosScalar(delta);
103:   *Fi = -Fd * PetscCosScalar(delta) + Fq * PetscSinScalar(delta);
104:   PetscFunctionReturn(PETSC_SUCCESS);
105: }

107: /* Converts from network frame ([phase a real,imag) to machine (dq) reference frame */
108: PetscErrorCode ri2dq(PetscScalar Fr, PetscScalar Fi, PetscScalar delta, PetscScalar *Fd, PetscScalar *Fq)
109: {
110:   PetscFunctionBegin;
111:   *Fd = Fr * PetscSinScalar(delta) - Fi * PetscCosScalar(delta);
112:   *Fq = Fr * PetscCosScalar(delta) + Fi * PetscSinScalar(delta);
113:   PetscFunctionReturn(PETSC_SUCCESS);
114: }

116: PetscErrorCode SetInitialGuess(Vec X, Userctx *user)
117: {
118:   Vec          Xgen, Xnet;
119:   PetscScalar *xgen, *xnet;
120:   PetscInt     i, idx = 0;
121:   PetscScalar  Vr, Vi, IGr, IGi, Vm, Vm2;
122:   PetscScalar  Eqp, Edp, delta;
123:   PetscScalar  Efd, RF, VR; /* Exciter variables */
124:   PetscScalar  Id, Iq;      /* Generator dq axis currents */
125:   PetscScalar  theta, Vd, Vq, SE;

127:   PetscFunctionBegin;
128:   M[0] = 2 * H[0] / w_s;
129:   M[1] = 2 * H[1] / w_s;
130:   M[2] = 2 * H[2] / w_s;
131:   D[0] = 0.1 * M[0];
132:   D[1] = 0.1 * M[1];
133:   D[2] = 0.1 * M[2];

135:   PetscCall(DMCompositeGetLocalVectors(user->dmpgrid, &Xgen, &Xnet));

137:   /* Network subsystem initialization */
138:   PetscCall(VecCopy(user->V0, Xnet));

140:   /* Generator subsystem initialization */
141:   PetscCall(VecGetArray(Xgen, &xgen));
142:   PetscCall(VecGetArray(Xnet, &xnet));

144:   for (i = 0; i < ngen; i++) {
145:     Vr  = xnet[2 * gbus[i]];     /* Real part of generator terminal voltage */
146:     Vi  = xnet[2 * gbus[i] + 1]; /* Imaginary part of the generator terminal voltage */
147:     Vm  = PetscSqrtScalar(Vr * Vr + Vi * Vi);
148:     Vm2 = Vm * Vm;
149:     IGr = (Vr * PG[i] + Vi * QG[i]) / Vm2;
150:     IGi = (Vi * PG[i] - Vr * QG[i]) / Vm2;

152:     delta = PetscAtan2Real(Vi + Xq[i] * IGr, Vr - Xq[i] * IGi); /* Machine angle */

154:     theta = PETSC_PI / 2.0 - delta;

156:     Id = IGr * PetscCosScalar(theta) - IGi * PetscSinScalar(theta); /* d-axis stator current */
157:     Iq = IGr * PetscSinScalar(theta) + IGi * PetscCosScalar(theta); /* q-axis stator current */

159:     Vd = Vr * PetscCosScalar(theta) - Vi * PetscSinScalar(theta);
160:     Vq = Vr * PetscSinScalar(theta) + Vi * PetscCosScalar(theta);

162:     Edp = Vd + Rs[i] * Id - Xqp[i] * Iq; /* d-axis transient EMF */
163:     Eqp = Vq + Rs[i] * Iq + Xdp[i] * Id; /* q-axis transient EMF */

165:     TM[i] = PG[i];

167:     /* The generator variables are ordered as [Eqp,Edp,delta,w,Id,Iq] */
168:     xgen[idx]     = Eqp;
169:     xgen[idx + 1] = Edp;
170:     xgen[idx + 2] = delta;
171:     xgen[idx + 3] = w_s;

173:     idx = idx + 4;

175:     xgen[idx]     = Id;
176:     xgen[idx + 1] = Iq;

178:     idx = idx + 2;

180:     /* Exciter */
181:     Efd = Eqp + (Xd[i] - Xdp[i]) * Id;
182:     SE  = k1[i] * PetscExpScalar(k2[i] * Efd);
183:     VR  = KE[i] * Efd + SE;
184:     RF  = KF[i] * Efd / TF[i];

186:     xgen[idx]     = Efd;
187:     xgen[idx + 1] = RF;
188:     xgen[idx + 2] = VR;

190:     Vref[i] = Vm + (VR / KA[i]);

192:     idx = idx + 3;
193:   }

195:   PetscCall(VecRestoreArray(Xgen, &xgen));
196:   PetscCall(VecRestoreArray(Xnet, &xnet));

198:   /* PetscCall(VecView(Xgen,0)); */
199:   PetscCall(DMCompositeGather(user->dmpgrid, INSERT_VALUES, X, Xgen, Xnet));
200:   PetscCall(DMCompositeRestoreLocalVectors(user->dmpgrid, &Xgen, &Xnet));
201:   PetscFunctionReturn(PETSC_SUCCESS);
202: }

204: /* Computes F = [-f(x,y);g(x,y)] */
205: PetscErrorCode ResidualFunction(SNES snes, Vec X, Vec F, Userctx *user)
206: {
207:   Vec          Xgen, Xnet, Fgen, Fnet;
208:   PetscScalar *xgen, *xnet, *fgen, *fnet;
209:   PetscInt     i, idx = 0;
210:   PetscScalar  Vr, Vi, Vm, Vm2;
211:   PetscScalar  Eqp, Edp, delta, w; /* Generator variables */
212:   PetscScalar  Efd, RF, VR;        /* Exciter variables */
213:   PetscScalar  Id, Iq;             /* Generator dq axis currents */
214:   PetscScalar  Vd, Vq, SE;
215:   PetscScalar  IGr, IGi, IDr, IDi;
216:   PetscScalar  Zdq_inv[4], det;
217:   PetscScalar  PD, QD, Vm0, *v0;
218:   PetscInt     k;

220:   PetscFunctionBegin;
221:   PetscCall(VecZeroEntries(F));
222:   PetscCall(DMCompositeGetLocalVectors(user->dmpgrid, &Xgen, &Xnet));
223:   PetscCall(DMCompositeGetLocalVectors(user->dmpgrid, &Fgen, &Fnet));
224:   PetscCall(DMCompositeScatter(user->dmpgrid, X, Xgen, Xnet));
225:   PetscCall(DMCompositeScatter(user->dmpgrid, F, Fgen, Fnet));

227:   /* Network current balance residual IG + Y*V + IL = 0. Only YV is added here.
228:      The generator current injection, IG, and load current injection, ID are added later
229:   */
230:   /* Note that the values in Ybus are stored assuming the imaginary current balance
231:      equation is ordered first followed by real current balance equation for each bus.
232:      Thus imaginary current contribution goes in location 2*i, and
233:      real current contribution in 2*i+1
234:   */
235:   PetscCall(MatMult(user->Ybus, Xnet, Fnet));

237:   PetscCall(VecGetArray(Xgen, &xgen));
238:   PetscCall(VecGetArray(Xnet, &xnet));
239:   PetscCall(VecGetArray(Fgen, &fgen));
240:   PetscCall(VecGetArray(Fnet, &fnet));

242:   /* Generator subsystem */
243:   for (i = 0; i < ngen; i++) {
244:     Eqp   = xgen[idx];
245:     Edp   = xgen[idx + 1];
246:     delta = xgen[idx + 2];
247:     w     = xgen[idx + 3];
248:     Id    = xgen[idx + 4];
249:     Iq    = xgen[idx + 5];
250:     Efd   = xgen[idx + 6];
251:     RF    = xgen[idx + 7];
252:     VR    = xgen[idx + 8];

254:     /* Generator differential equations */
255:     fgen[idx]     = (Eqp + (Xd[i] - Xdp[i]) * Id - Efd) / Td0p[i];
256:     fgen[idx + 1] = (Edp - (Xq[i] - Xqp[i]) * Iq) / Tq0p[i];
257:     fgen[idx + 2] = -w + w_s;
258:     fgen[idx + 3] = (-TM[i] + Edp * Id + Eqp * Iq + (Xqp[i] - Xdp[i]) * Id * Iq + D[i] * (w - w_s)) / M[i];

260:     Vr = xnet[2 * gbus[i]];     /* Real part of generator terminal voltage */
261:     Vi = xnet[2 * gbus[i] + 1]; /* Imaginary part of the generator terminal voltage */

263:     PetscCall(ri2dq(Vr, Vi, delta, &Vd, &Vq));
264:     /* Algebraic equations for stator currents */
265:     det = Rs[i] * Rs[i] + Xdp[i] * Xqp[i];

267:     Zdq_inv[0] = Rs[i] / det;
268:     Zdq_inv[1] = Xqp[i] / det;
269:     Zdq_inv[2] = -Xdp[i] / det;
270:     Zdq_inv[3] = Rs[i] / det;

272:     fgen[idx + 4] = Zdq_inv[0] * (-Edp + Vd) + Zdq_inv[1] * (-Eqp + Vq) + Id;
273:     fgen[idx + 5] = Zdq_inv[2] * (-Edp + Vd) + Zdq_inv[3] * (-Eqp + Vq) + Iq;

275:     /* Add generator current injection to network */
276:     PetscCall(dq2ri(Id, Iq, delta, &IGr, &IGi));

278:     fnet[2 * gbus[i]] -= IGi;
279:     fnet[2 * gbus[i] + 1] -= IGr;

281:     Vm = PetscSqrtScalar(Vd * Vd + Vq * Vq);

283:     SE = k1[i] * PetscExpScalar(k2[i] * Efd);

285:     /* Exciter differential equations */
286:     fgen[idx + 6] = (KE[i] * Efd + SE - VR) / TE[i];
287:     fgen[idx + 7] = (RF - KF[i] * Efd / TF[i]) / TF[i];
288:     fgen[idx + 8] = (VR - KA[i] * RF + KA[i] * KF[i] * Efd / TF[i] - KA[i] * (Vref[i] - Vm)) / TA[i];

290:     idx = idx + 9;
291:   }

293:   PetscCall(VecGetArray(user->V0, &v0));
294:   for (i = 0; i < nload; i++) {
295:     Vr  = xnet[2 * lbus[i]];     /* Real part of load bus voltage */
296:     Vi  = xnet[2 * lbus[i] + 1]; /* Imaginary part of the load bus voltage */
297:     Vm  = PetscSqrtScalar(Vr * Vr + Vi * Vi);
298:     Vm2 = Vm * Vm;
299:     Vm0 = PetscSqrtScalar(v0[2 * lbus[i]] * v0[2 * lbus[i]] + v0[2 * lbus[i] + 1] * v0[2 * lbus[i] + 1]);
300:     PD = QD = 0.0;
301:     for (k = 0; k < ld_nsegsp[i]; k++) PD += ld_alphap[k] * PD0[i] * PetscPowScalar((Vm / Vm0), ld_betap[k]);
302:     for (k = 0; k < ld_nsegsq[i]; k++) QD += ld_alphaq[k] * QD0[i] * PetscPowScalar((Vm / Vm0), ld_betaq[k]);

304:     /* Load currents */
305:     IDr = (PD * Vr + QD * Vi) / Vm2;
306:     IDi = (-QD * Vr + PD * Vi) / Vm2;

308:     fnet[2 * lbus[i]] += IDi;
309:     fnet[2 * lbus[i] + 1] += IDr;
310:   }
311:   PetscCall(VecRestoreArray(user->V0, &v0));

313:   PetscCall(VecRestoreArray(Xgen, &xgen));
314:   PetscCall(VecRestoreArray(Xnet, &xnet));
315:   PetscCall(VecRestoreArray(Fgen, &fgen));
316:   PetscCall(VecRestoreArray(Fnet, &fnet));

318:   PetscCall(DMCompositeGather(user->dmpgrid, INSERT_VALUES, F, Fgen, Fnet));
319:   PetscCall(DMCompositeRestoreLocalVectors(user->dmpgrid, &Xgen, &Xnet));
320:   PetscCall(DMCompositeRestoreLocalVectors(user->dmpgrid, &Fgen, &Fnet));
321:   PetscFunctionReturn(PETSC_SUCCESS);
322: }

324: /* \dot{x} - f(x,y)
325:      g(x,y) = 0
326:  */
327: PetscErrorCode IFunction(TS ts, PetscReal t, Vec X, Vec Xdot, Vec F, Userctx *user)
328: {
329:   SNES               snes;
330:   PetscScalar       *f;
331:   const PetscScalar *xdot;
332:   PetscInt           i;

334:   PetscFunctionBegin;
335:   user->t = t;

337:   PetscCall(TSGetSNES(ts, &snes));
338:   PetscCall(ResidualFunction(snes, X, F, user));
339:   PetscCall(VecGetArray(F, &f));
340:   PetscCall(VecGetArrayRead(Xdot, &xdot));
341:   for (i = 0; i < ngen; i++) {
342:     f[9 * i] += xdot[9 * i];
343:     f[9 * i + 1] += xdot[9 * i + 1];
344:     f[9 * i + 2] += xdot[9 * i + 2];
345:     f[9 * i + 3] += xdot[9 * i + 3];
346:     f[9 * i + 6] += xdot[9 * i + 6];
347:     f[9 * i + 7] += xdot[9 * i + 7];
348:     f[9 * i + 8] += xdot[9 * i + 8];
349:   }
350:   PetscCall(VecRestoreArray(F, &f));
351:   PetscCall(VecRestoreArrayRead(Xdot, &xdot));
352:   PetscFunctionReturn(PETSC_SUCCESS);
353: }

355: /* This function is used for solving the algebraic system only during fault on and
356:    off times. It computes the entire F and then zeros out the part corresponding to
357:    differential equations
358:  F = [0;g(y)];
359: */
360: PetscErrorCode AlgFunction(SNES snes, Vec X, Vec F, void *ctx)
361: {
362:   Userctx     *user = (Userctx *)ctx;
363:   PetscScalar *f;
364:   PetscInt     i;

366:   PetscFunctionBegin;
367:   PetscCall(ResidualFunction(snes, X, F, user));
368:   PetscCall(VecGetArray(F, &f));
369:   for (i = 0; i < ngen; i++) {
370:     f[9 * i]     = 0;
371:     f[9 * i + 1] = 0;
372:     f[9 * i + 2] = 0;
373:     f[9 * i + 3] = 0;
374:     f[9 * i + 6] = 0;
375:     f[9 * i + 7] = 0;
376:     f[9 * i + 8] = 0;
377:   }
378:   PetscCall(VecRestoreArray(F, &f));
379:   PetscFunctionReturn(PETSC_SUCCESS);
380: }

382: PetscErrorCode PreallocateJacobian(Mat J, Userctx *user)
383: {
384:   PetscInt *d_nnz;
385:   PetscInt  i, idx = 0, start = 0;
386:   PetscInt  ncols;

388:   PetscFunctionBegin;
389:   PetscCall(PetscMalloc1(user->neqs_pgrid, &d_nnz));
390:   for (i = 0; i < user->neqs_pgrid; i++) d_nnz[i] = 0;
391:   /* Generator subsystem */
392:   for (i = 0; i < ngen; i++) {
393:     d_nnz[idx] += 3;
394:     d_nnz[idx + 1] += 2;
395:     d_nnz[idx + 2] += 2;
396:     d_nnz[idx + 3] += 5;
397:     d_nnz[idx + 4] += 6;
398:     d_nnz[idx + 5] += 6;

400:     d_nnz[user->neqs_gen + 2 * gbus[i]] += 3;
401:     d_nnz[user->neqs_gen + 2 * gbus[i] + 1] += 3;

403:     d_nnz[idx + 6] += 2;
404:     d_nnz[idx + 7] += 2;
405:     d_nnz[idx + 8] += 5;

407:     idx = idx + 9;
408:   }

410:   start = user->neqs_gen;

412:   for (i = 0; i < nbus; i++) {
413:     PetscCall(MatGetRow(user->Ybus, 2 * i, &ncols, NULL, NULL));
414:     d_nnz[start + 2 * i] += ncols;
415:     d_nnz[start + 2 * i + 1] += ncols;
416:     PetscCall(MatRestoreRow(user->Ybus, 2 * i, &ncols, NULL, NULL));
417:   }

419:   PetscCall(MatSeqAIJSetPreallocation(J, 0, d_nnz));

421:   PetscCall(PetscFree(d_nnz));
422:   PetscFunctionReturn(PETSC_SUCCESS);
423: }

425: /*
426:    J = [-df_dx, -df_dy
427:         dg_dx, dg_dy]
428: */
429: PetscErrorCode ResidualJacobian(SNES snes, Vec X, Mat J, Mat B, void *ctx)
430: {
431:   Userctx           *user = (Userctx *)ctx;
432:   Vec                Xgen, Xnet;
433:   PetscScalar       *xgen, *xnet;
434:   PetscInt           i, idx = 0;
435:   PetscScalar        Vr, Vi, Vm, Vm2;
436:   PetscScalar        Eqp, Edp, delta; /* Generator variables */
437:   PetscScalar        Efd;             /* Exciter variables */
438:   PetscScalar        Id, Iq;          /* Generator dq axis currents */
439:   PetscScalar        Vd, Vq;
440:   PetscScalar        val[10];
441:   PetscInt           row[2], col[10];
442:   PetscInt           net_start = user->neqs_gen;
443:   PetscScalar        Zdq_inv[4], det;
444:   PetscScalar        dVd_dVr, dVd_dVi, dVq_dVr, dVq_dVi, dVd_ddelta, dVq_ddelta;
445:   PetscScalar        dIGr_ddelta, dIGi_ddelta, dIGr_dId, dIGr_dIq, dIGi_dId, dIGi_dIq;
446:   PetscScalar        dSE_dEfd;
447:   PetscScalar        dVm_dVd, dVm_dVq, dVm_dVr, dVm_dVi;
448:   PetscInt           ncols;
449:   const PetscInt    *cols;
450:   const PetscScalar *yvals;
451:   PetscInt           k;
452:   PetscScalar        PD, QD, Vm0, *v0, Vm4;
453:   PetscScalar        dPD_dVr, dPD_dVi, dQD_dVr, dQD_dVi;
454:   PetscScalar        dIDr_dVr, dIDr_dVi, dIDi_dVr, dIDi_dVi;

456:   PetscFunctionBegin;
457:   PetscCall(MatZeroEntries(B));
458:   PetscCall(DMCompositeGetLocalVectors(user->dmpgrid, &Xgen, &Xnet));
459:   PetscCall(DMCompositeScatter(user->dmpgrid, X, Xgen, Xnet));

461:   PetscCall(VecGetArray(Xgen, &xgen));
462:   PetscCall(VecGetArray(Xnet, &xnet));

464:   /* Generator subsystem */
465:   for (i = 0; i < ngen; i++) {
466:     Eqp   = xgen[idx];
467:     Edp   = xgen[idx + 1];
468:     delta = xgen[idx + 2];
469:     Id    = xgen[idx + 4];
470:     Iq    = xgen[idx + 5];
471:     Efd   = xgen[idx + 6];

473:     /*    fgen[idx]   = (Eqp + (Xd[i] - Xdp[i])*Id - Efd)/Td0p[i]; */
474:     row[0] = idx;
475:     col[0] = idx;
476:     col[1] = idx + 4;
477:     col[2] = idx + 6;
478:     val[0] = 1 / Td0p[i];
479:     val[1] = (Xd[i] - Xdp[i]) / Td0p[i];
480:     val[2] = -1 / Td0p[i];

482:     PetscCall(MatSetValues(J, 1, row, 3, col, val, INSERT_VALUES));

484:     /*    fgen[idx+1] = (Edp - (Xq[i] - Xqp[i])*Iq)/Tq0p[i]; */
485:     row[0] = idx + 1;
486:     col[0] = idx + 1;
487:     col[1] = idx + 5;
488:     val[0] = 1 / Tq0p[i];
489:     val[1] = -(Xq[i] - Xqp[i]) / Tq0p[i];
490:     PetscCall(MatSetValues(J, 1, row, 2, col, val, INSERT_VALUES));

492:     /*    fgen[idx+2] = - w + w_s; */
493:     row[0] = idx + 2;
494:     col[0] = idx + 2;
495:     col[1] = idx + 3;
496:     val[0] = 0;
497:     val[1] = -1;
498:     PetscCall(MatSetValues(J, 1, row, 2, col, val, INSERT_VALUES));

500:     /*    fgen[idx+3] = (-TM[i] + Edp*Id + Eqp*Iq + (Xqp[i] - Xdp[i])*Id*Iq + D[i]*(w - w_s))/M[i]; */
501:     row[0] = idx + 3;
502:     col[0] = idx;
503:     col[1] = idx + 1;
504:     col[2] = idx + 3;
505:     col[3] = idx + 4;
506:     col[4] = idx + 5;
507:     val[0] = Iq / M[i];
508:     val[1] = Id / M[i];
509:     val[2] = D[i] / M[i];
510:     val[3] = (Edp + (Xqp[i] - Xdp[i]) * Iq) / M[i];
511:     val[4] = (Eqp + (Xqp[i] - Xdp[i]) * Id) / M[i];
512:     PetscCall(MatSetValues(J, 1, row, 5, col, val, INSERT_VALUES));

514:     Vr = xnet[2 * gbus[i]];     /* Real part of generator terminal voltage */
515:     Vi = xnet[2 * gbus[i] + 1]; /* Imaginary part of the generator terminal voltage */
516:     PetscCall(ri2dq(Vr, Vi, delta, &Vd, &Vq));

518:     det = Rs[i] * Rs[i] + Xdp[i] * Xqp[i];

520:     Zdq_inv[0] = Rs[i] / det;
521:     Zdq_inv[1] = Xqp[i] / det;
522:     Zdq_inv[2] = -Xdp[i] / det;
523:     Zdq_inv[3] = Rs[i] / det;

525:     dVd_dVr    = PetscSinScalar(delta);
526:     dVd_dVi    = -PetscCosScalar(delta);
527:     dVq_dVr    = PetscCosScalar(delta);
528:     dVq_dVi    = PetscSinScalar(delta);
529:     dVd_ddelta = Vr * PetscCosScalar(delta) + Vi * PetscSinScalar(delta);
530:     dVq_ddelta = -Vr * PetscSinScalar(delta) + Vi * PetscCosScalar(delta);

532:     /*    fgen[idx+4] = Zdq_inv[0]*(-Edp + Vd) + Zdq_inv[1]*(-Eqp + Vq) + Id; */
533:     row[0] = idx + 4;
534:     col[0] = idx;
535:     col[1] = idx + 1;
536:     col[2] = idx + 2;
537:     val[0] = -Zdq_inv[1];
538:     val[1] = -Zdq_inv[0];
539:     val[2] = Zdq_inv[0] * dVd_ddelta + Zdq_inv[1] * dVq_ddelta;
540:     col[3] = idx + 4;
541:     col[4] = net_start + 2 * gbus[i];
542:     col[5] = net_start + 2 * gbus[i] + 1;
543:     val[3] = 1;
544:     val[4] = Zdq_inv[0] * dVd_dVr + Zdq_inv[1] * dVq_dVr;
545:     val[5] = Zdq_inv[0] * dVd_dVi + Zdq_inv[1] * dVq_dVi;
546:     PetscCall(MatSetValues(J, 1, row, 6, col, val, INSERT_VALUES));

548:     /*  fgen[idx+5] = Zdq_inv[2]*(-Edp + Vd) + Zdq_inv[3]*(-Eqp + Vq) + Iq; */
549:     row[0] = idx + 5;
550:     col[0] = idx;
551:     col[1] = idx + 1;
552:     col[2] = idx + 2;
553:     val[0] = -Zdq_inv[3];
554:     val[1] = -Zdq_inv[2];
555:     val[2] = Zdq_inv[2] * dVd_ddelta + Zdq_inv[3] * dVq_ddelta;
556:     col[3] = idx + 5;
557:     col[4] = net_start + 2 * gbus[i];
558:     col[5] = net_start + 2 * gbus[i] + 1;
559:     val[3] = 1;
560:     val[4] = Zdq_inv[2] * dVd_dVr + Zdq_inv[3] * dVq_dVr;
561:     val[5] = Zdq_inv[2] * dVd_dVi + Zdq_inv[3] * dVq_dVi;
562:     PetscCall(MatSetValues(J, 1, row, 6, col, val, INSERT_VALUES));

564:     dIGr_ddelta = Id * PetscCosScalar(delta) - Iq * PetscSinScalar(delta);
565:     dIGi_ddelta = Id * PetscSinScalar(delta) + Iq * PetscCosScalar(delta);
566:     dIGr_dId    = PetscSinScalar(delta);
567:     dIGr_dIq    = PetscCosScalar(delta);
568:     dIGi_dId    = -PetscCosScalar(delta);
569:     dIGi_dIq    = PetscSinScalar(delta);

571:     /* fnet[2*gbus[i]]   -= IGi; */
572:     row[0] = net_start + 2 * gbus[i];
573:     col[0] = idx + 2;
574:     col[1] = idx + 4;
575:     col[2] = idx + 5;
576:     val[0] = -dIGi_ddelta;
577:     val[1] = -dIGi_dId;
578:     val[2] = -dIGi_dIq;
579:     PetscCall(MatSetValues(J, 1, row, 3, col, val, INSERT_VALUES));

581:     /* fnet[2*gbus[i]+1]   -= IGr; */
582:     row[0] = net_start + 2 * gbus[i] + 1;
583:     col[0] = idx + 2;
584:     col[1] = idx + 4;
585:     col[2] = idx + 5;
586:     val[0] = -dIGr_ddelta;
587:     val[1] = -dIGr_dId;
588:     val[2] = -dIGr_dIq;
589:     PetscCall(MatSetValues(J, 1, row, 3, col, val, INSERT_VALUES));

591:     Vm = PetscSqrtScalar(Vd * Vd + Vq * Vq);

593:     /*    fgen[idx+6] = (KE[i]*Efd + SE - VR)/TE[i]; */
594:     /*    SE  = k1[i]*PetscExpScalar(k2[i]*Efd); */

596:     dSE_dEfd = k1[i] * k2[i] * PetscExpScalar(k2[i] * Efd);

598:     row[0] = idx + 6;
599:     col[0] = idx + 6;
600:     col[1] = idx + 8;
601:     val[0] = (KE[i] + dSE_dEfd) / TE[i];
602:     val[1] = -1 / TE[i];
603:     PetscCall(MatSetValues(J, 1, row, 2, col, val, INSERT_VALUES));

605:     /* Exciter differential equations */

607:     /*    fgen[idx+7] = (RF - KF[i]*Efd/TF[i])/TF[i]; */
608:     row[0] = idx + 7;
609:     col[0] = idx + 6;
610:     col[1] = idx + 7;
611:     val[0] = (-KF[i] / TF[i]) / TF[i];
612:     val[1] = 1 / TF[i];
613:     PetscCall(MatSetValues(J, 1, row, 2, col, val, INSERT_VALUES));

615:     /*    fgen[idx+8] = (VR - KA[i]*RF + KA[i]*KF[i]*Efd/TF[i] - KA[i]*(Vref[i] - Vm))/TA[i]; */
616:     /* Vm = (Vd^2 + Vq^2)^0.5; */
617:     dVm_dVd = Vd / Vm;
618:     dVm_dVq = Vq / Vm;
619:     dVm_dVr = dVm_dVd * dVd_dVr + dVm_dVq * dVq_dVr;
620:     dVm_dVi = dVm_dVd * dVd_dVi + dVm_dVq * dVq_dVi;
621:     row[0]  = idx + 8;
622:     col[0]  = idx + 6;
623:     col[1]  = idx + 7;
624:     col[2]  = idx + 8;
625:     val[0]  = (KA[i] * KF[i] / TF[i]) / TA[i];
626:     val[1]  = -KA[i] / TA[i];
627:     val[2]  = 1 / TA[i];
628:     col[3]  = net_start + 2 * gbus[i];
629:     col[4]  = net_start + 2 * gbus[i] + 1;
630:     val[3]  = KA[i] * dVm_dVr / TA[i];
631:     val[4]  = KA[i] * dVm_dVi / TA[i];
632:     PetscCall(MatSetValues(J, 1, row, 5, col, val, INSERT_VALUES));
633:     idx = idx + 9;
634:   }

636:   for (i = 0; i < nbus; i++) {
637:     PetscCall(MatGetRow(user->Ybus, 2 * i, &ncols, &cols, &yvals));
638:     row[0] = net_start + 2 * i;
639:     for (k = 0; k < ncols; k++) {
640:       col[k] = net_start + cols[k];
641:       val[k] = yvals[k];
642:     }
643:     PetscCall(MatSetValues(J, 1, row, ncols, col, val, INSERT_VALUES));
644:     PetscCall(MatRestoreRow(user->Ybus, 2 * i, &ncols, &cols, &yvals));

646:     PetscCall(MatGetRow(user->Ybus, 2 * i + 1, &ncols, &cols, &yvals));
647:     row[0] = net_start + 2 * i + 1;
648:     for (k = 0; k < ncols; k++) {
649:       col[k] = net_start + cols[k];
650:       val[k] = yvals[k];
651:     }
652:     PetscCall(MatSetValues(J, 1, row, ncols, col, val, INSERT_VALUES));
653:     PetscCall(MatRestoreRow(user->Ybus, 2 * i + 1, &ncols, &cols, &yvals));
654:   }

656:   PetscCall(MatAssemblyBegin(J, MAT_FLUSH_ASSEMBLY));
657:   PetscCall(MatAssemblyEnd(J, MAT_FLUSH_ASSEMBLY));

659:   PetscCall(VecGetArray(user->V0, &v0));
660:   for (i = 0; i < nload; i++) {
661:     Vr  = xnet[2 * lbus[i]];     /* Real part of load bus voltage */
662:     Vi  = xnet[2 * lbus[i] + 1]; /* Imaginary part of the load bus voltage */
663:     Vm  = PetscSqrtScalar(Vr * Vr + Vi * Vi);
664:     Vm2 = Vm * Vm;
665:     Vm4 = Vm2 * Vm2;
666:     Vm0 = PetscSqrtScalar(v0[2 * lbus[i]] * v0[2 * lbus[i]] + v0[2 * lbus[i] + 1] * v0[2 * lbus[i] + 1]);
667:     PD = QD = 0.0;
668:     dPD_dVr = dPD_dVi = dQD_dVr = dQD_dVi = 0.0;
669:     for (k = 0; k < ld_nsegsp[i]; k++) {
670:       PD += ld_alphap[k] * PD0[i] * PetscPowScalar((Vm / Vm0), ld_betap[k]);
671:       dPD_dVr += ld_alphap[k] * ld_betap[k] * PD0[i] * PetscPowScalar((1 / Vm0), ld_betap[k]) * Vr * PetscPowScalar(Vm, (ld_betap[k] - 2));
672:       dPD_dVi += ld_alphap[k] * ld_betap[k] * PD0[i] * PetscPowScalar((1 / Vm0), ld_betap[k]) * Vi * PetscPowScalar(Vm, (ld_betap[k] - 2));
673:     }
674:     for (k = 0; k < ld_nsegsq[i]; k++) {
675:       QD += ld_alphaq[k] * QD0[i] * PetscPowScalar((Vm / Vm0), ld_betaq[k]);
676:       dQD_dVr += ld_alphaq[k] * ld_betaq[k] * QD0[i] * PetscPowScalar((1 / Vm0), ld_betaq[k]) * Vr * PetscPowScalar(Vm, (ld_betaq[k] - 2));
677:       dQD_dVi += ld_alphaq[k] * ld_betaq[k] * QD0[i] * PetscPowScalar((1 / Vm0), ld_betaq[k]) * Vi * PetscPowScalar(Vm, (ld_betaq[k] - 2));
678:     }

680:     /*    IDr = (PD*Vr + QD*Vi)/Vm2; */
681:     /*    IDi = (-QD*Vr + PD*Vi)/Vm2; */

683:     dIDr_dVr = (dPD_dVr * Vr + dQD_dVr * Vi + PD) / Vm2 - ((PD * Vr + QD * Vi) * 2 * Vr) / Vm4;
684:     dIDr_dVi = (dPD_dVi * Vr + dQD_dVi * Vi + QD) / Vm2 - ((PD * Vr + QD * Vi) * 2 * Vi) / Vm4;

686:     dIDi_dVr = (-dQD_dVr * Vr + dPD_dVr * Vi - QD) / Vm2 - ((-QD * Vr + PD * Vi) * 2 * Vr) / Vm4;
687:     dIDi_dVi = (-dQD_dVi * Vr + dPD_dVi * Vi + PD) / Vm2 - ((-QD * Vr + PD * Vi) * 2 * Vi) / Vm4;

689:     /*    fnet[2*lbus[i]]   += IDi; */
690:     row[0] = net_start + 2 * lbus[i];
691:     col[0] = net_start + 2 * lbus[i];
692:     col[1] = net_start + 2 * lbus[i] + 1;
693:     val[0] = dIDi_dVr;
694:     val[1] = dIDi_dVi;
695:     PetscCall(MatSetValues(J, 1, row, 2, col, val, ADD_VALUES));
696:     /*    fnet[2*lbus[i]+1] += IDr; */
697:     row[0] = net_start + 2 * lbus[i] + 1;
698:     col[0] = net_start + 2 * lbus[i];
699:     col[1] = net_start + 2 * lbus[i] + 1;
700:     val[0] = dIDr_dVr;
701:     val[1] = dIDr_dVi;
702:     PetscCall(MatSetValues(J, 1, row, 2, col, val, ADD_VALUES));
703:   }
704:   PetscCall(VecRestoreArray(user->V0, &v0));

706:   PetscCall(VecRestoreArray(Xgen, &xgen));
707:   PetscCall(VecRestoreArray(Xnet, &xnet));

709:   PetscCall(DMCompositeRestoreLocalVectors(user->dmpgrid, &Xgen, &Xnet));

711:   PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
712:   PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
713:   PetscFunctionReturn(PETSC_SUCCESS);
714: }

716: /*
717:    J = [I, 0
718:         dg_dx, dg_dy]
719: */
720: PetscErrorCode AlgJacobian(SNES snes, Vec X, Mat A, Mat B, void *ctx)
721: {
722:   Userctx *user = (Userctx *)ctx;

724:   PetscFunctionBegin;
725:   PetscCall(ResidualJacobian(snes, X, A, B, ctx));
726:   PetscCall(MatSetOption(A, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE));
727:   PetscCall(MatZeroRowsIS(A, user->is_diff, 1.0, NULL, NULL));
728:   PetscFunctionReturn(PETSC_SUCCESS);
729: }

731: /*
732:    J = [a*I-df_dx, -df_dy
733:         dg_dx, dg_dy]
734: */

736: PetscErrorCode IJacobian(TS ts, PetscReal t, Vec X, Vec Xdot, PetscReal a, Mat A, Mat B, Userctx *user)
737: {
738:   SNES        snes;
739:   PetscScalar atmp = (PetscScalar)a;
740:   PetscInt    i, row;

742:   PetscFunctionBegin;
743:   user->t = t;

745:   PetscCall(TSGetSNES(ts, &snes));
746:   PetscCall(ResidualJacobian(snes, X, A, B, user));
747:   for (i = 0; i < ngen; i++) {
748:     row = 9 * i;
749:     PetscCall(MatSetValues(A, 1, &row, 1, &row, &atmp, ADD_VALUES));
750:     row = 9 * i + 1;
751:     PetscCall(MatSetValues(A, 1, &row, 1, &row, &atmp, ADD_VALUES));
752:     row = 9 * i + 2;
753:     PetscCall(MatSetValues(A, 1, &row, 1, &row, &atmp, ADD_VALUES));
754:     row = 9 * i + 3;
755:     PetscCall(MatSetValues(A, 1, &row, 1, &row, &atmp, ADD_VALUES));
756:     row = 9 * i + 6;
757:     PetscCall(MatSetValues(A, 1, &row, 1, &row, &atmp, ADD_VALUES));
758:     row = 9 * i + 7;
759:     PetscCall(MatSetValues(A, 1, &row, 1, &row, &atmp, ADD_VALUES));
760:     row = 9 * i + 8;
761:     PetscCall(MatSetValues(A, 1, &row, 1, &row, &atmp, ADD_VALUES));
762:   }
763:   PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
764:   PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
765:   PetscFunctionReturn(PETSC_SUCCESS);
766: }

768: static PetscErrorCode CostIntegrand(TS ts, PetscReal t, Vec U, Vec R, Userctx *user)
769: {
770:   PetscScalar       *r;
771:   const PetscScalar *u;
772:   PetscInt           idx;
773:   Vec                Xgen, Xnet;
774:   PetscScalar       *xgen;
775:   PetscInt           i;

777:   PetscFunctionBegin;
778:   PetscCall(DMCompositeGetLocalVectors(user->dmpgrid, &Xgen, &Xnet));
779:   PetscCall(DMCompositeScatter(user->dmpgrid, U, Xgen, Xnet));

781:   PetscCall(VecGetArray(Xgen, &xgen));

783:   PetscCall(VecGetArrayRead(U, &u));
784:   PetscCall(VecGetArray(R, &r));
785:   r[0] = 0.;

787:   idx = 0;
788:   for (i = 0; i < ngen; i++) {
789:     r[0] += PetscPowScalarInt(PetscMax(0., PetscMax(xgen[idx + 3] / (2. * PETSC_PI) - user->freq_u, user->freq_l - xgen[idx + 3] / (2. * PETSC_PI))), user->pow);
790:     idx += 9;
791:   }
792:   PetscCall(VecRestoreArray(R, &r));
793:   PetscCall(VecRestoreArrayRead(U, &u));
794:   PetscCall(DMCompositeRestoreLocalVectors(user->dmpgrid, &Xgen, &Xnet));
795:   PetscFunctionReturn(PETSC_SUCCESS);
796: }

798: static PetscErrorCode MonitorUpdateQ(TS ts, PetscInt stepnum, PetscReal time, Vec X, void *ctx0)
799: {
800:   Vec       C, *Y;
801:   PetscInt  Nr;
802:   PetscReal h, theta;
803:   Userctx  *ctx = (Userctx *)ctx0;

805:   PetscFunctionBegin;
806:   theta = 0.5;
807:   PetscCall(TSGetStages(ts, &Nr, &Y));
808:   PetscCall(TSGetTimeStep(ts, &h));
809:   PetscCall(VecDuplicate(ctx->vec_q, &C));
810:   /* compute integrals */
811:   if (stepnum > 0) {
812:     PetscCall(CostIntegrand(ts, time, X, C, ctx));
813:     PetscCall(VecAXPY(ctx->vec_q, h * theta, C));
814:     PetscCall(CostIntegrand(ts, time + h * theta, Y[0], C, ctx));
815:     PetscCall(VecAXPY(ctx->vec_q, h * (1 - theta), C));
816:   }
817:   PetscCall(VecDestroy(&C));
818:   PetscFunctionReturn(PETSC_SUCCESS);
819: }

821: int main(int argc, char **argv)
822: {
823:   Userctx      user;
824:   Vec          p;
825:   PetscScalar *x_ptr;
826:   PetscMPIInt  size;
827:   PetscInt     i;
828:   KSP          ksp;
829:   PC           pc;
830:   PetscInt    *idx2;
831:   Tao          tao;
832:   Vec          lowerb, upperb;

834:   PetscFunctionBeginUser;
835:   PetscFunctionBeginUser;
836:   PetscCall(PetscInitialize(&argc, &argv, "petscoptions", help));
837:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
838:   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Only for sequential runs");

840:   PetscCall(VecCreateSeq(PETSC_COMM_WORLD, 1, &user.vec_q));

842:   user.neqs_gen   = 9 * ngen; /* # eqs. for generator subsystem */
843:   user.neqs_net   = 2 * nbus; /* # eqs. for network subsystem   */
844:   user.neqs_pgrid = user.neqs_gen + user.neqs_net;

846:   /* Create indices for differential and algebraic equations */
847:   PetscCall(PetscMalloc1(7 * ngen, &idx2));
848:   for (i = 0; i < ngen; i++) {
849:     idx2[7 * i]     = 9 * i;
850:     idx2[7 * i + 1] = 9 * i + 1;
851:     idx2[7 * i + 2] = 9 * i + 2;
852:     idx2[7 * i + 3] = 9 * i + 3;
853:     idx2[7 * i + 4] = 9 * i + 6;
854:     idx2[7 * i + 5] = 9 * i + 7;
855:     idx2[7 * i + 6] = 9 * i + 8;
856:   }
857:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, 7 * ngen, idx2, PETSC_COPY_VALUES, &user.is_diff));
858:   PetscCall(ISComplement(user.is_diff, 0, user.neqs_pgrid, &user.is_alg));
859:   PetscCall(PetscFree(idx2));

861:   /* Set run time options */
862:   PetscOptionsBegin(PETSC_COMM_WORLD, NULL, "Transient stability fault options", "");
863:   {
864:     user.tfaulton  = 1.0;
865:     user.tfaultoff = 1.2;
866:     user.Rfault    = 0.0001;
867:     user.faultbus  = 8;
868:     PetscCall(PetscOptionsReal("-tfaulton", "", "", user.tfaulton, &user.tfaulton, NULL));
869:     PetscCall(PetscOptionsReal("-tfaultoff", "", "", user.tfaultoff, &user.tfaultoff, NULL));
870:     PetscCall(PetscOptionsInt("-faultbus", "", "", user.faultbus, &user.faultbus, NULL));
871:     user.t0   = 0.0;
872:     user.tmax = 1.5;
873:     PetscCall(PetscOptionsReal("-t0", "", "", user.t0, &user.t0, NULL));
874:     PetscCall(PetscOptionsReal("-tmax", "", "", user.tmax, &user.tmax, NULL));
875:     user.freq_u = 61.0;
876:     user.freq_l = 59.0;
877:     user.pow    = 2;
878:     PetscCall(PetscOptionsReal("-frequ", "", "", user.freq_u, &user.freq_u, NULL));
879:     PetscCall(PetscOptionsReal("-freql", "", "", user.freq_l, &user.freq_l, NULL));
880:     PetscCall(PetscOptionsInt("-pow", "", "", user.pow, &user.pow, NULL));
881:   }
882:   PetscOptionsEnd();

884:   /* Create DMs for generator and network subsystems */
885:   PetscCall(DMDACreate1d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, user.neqs_gen, 1, 1, NULL, &user.dmgen));
886:   PetscCall(DMSetOptionsPrefix(user.dmgen, "dmgen_"));
887:   PetscCall(DMSetFromOptions(user.dmgen));
888:   PetscCall(DMSetUp(user.dmgen));
889:   PetscCall(DMDACreate1d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, user.neqs_net, 1, 1, NULL, &user.dmnet));
890:   PetscCall(DMSetOptionsPrefix(user.dmnet, "dmnet_"));
891:   PetscCall(DMSetFromOptions(user.dmnet));
892:   PetscCall(DMSetUp(user.dmnet));
893:   /* Create a composite DM packer and add the two DMs */
894:   PetscCall(DMCompositeCreate(PETSC_COMM_WORLD, &user.dmpgrid));
895:   PetscCall(DMSetOptionsPrefix(user.dmpgrid, "pgrid_"));
896:   PetscCall(DMCompositeAddDM(user.dmpgrid, user.dmgen));
897:   PetscCall(DMCompositeAddDM(user.dmpgrid, user.dmnet));

899:   /* Create TAO solver and set desired solution method */
900:   PetscCall(TaoCreate(PETSC_COMM_WORLD, &tao));
901:   PetscCall(TaoSetType(tao, TAOBLMVM));
902:   /*
903:      Optimization starts
904:   */
905:   /* Set initial solution guess */
906:   PetscCall(VecCreateSeq(PETSC_COMM_WORLD, 3, &p));
907:   PetscCall(VecGetArray(p, &x_ptr));
908:   x_ptr[0] = PG[0];
909:   x_ptr[1] = PG[1];
910:   x_ptr[2] = PG[2];
911:   PetscCall(VecRestoreArray(p, &x_ptr));

913:   PetscCall(TaoSetSolution(tao, p));
914:   /* Set routine for function and gradient evaluation */
915:   PetscCall(TaoSetObjective(tao, FormFunction, (void *)&user));
916:   PetscCall(TaoSetGradient(tao, NULL, TaoDefaultComputeGradient, (void *)&user));

918:   /* Set bounds for the optimization */
919:   PetscCall(VecDuplicate(p, &lowerb));
920:   PetscCall(VecDuplicate(p, &upperb));
921:   PetscCall(VecGetArray(lowerb, &x_ptr));
922:   x_ptr[0] = 0.5;
923:   x_ptr[1] = 0.5;
924:   x_ptr[2] = 0.5;
925:   PetscCall(VecRestoreArray(lowerb, &x_ptr));
926:   PetscCall(VecGetArray(upperb, &x_ptr));
927:   x_ptr[0] = 2.0;
928:   x_ptr[1] = 2.0;
929:   x_ptr[2] = 2.0;
930:   PetscCall(VecRestoreArray(upperb, &x_ptr));
931:   PetscCall(TaoSetVariableBounds(tao, lowerb, upperb));

933:   /* Check for any TAO command line options */
934:   PetscCall(TaoSetFromOptions(tao));
935:   PetscCall(TaoGetKSP(tao, &ksp));
936:   if (ksp) {
937:     PetscCall(KSPGetPC(ksp, &pc));
938:     PetscCall(PCSetType(pc, PCNONE));
939:   }

941:   /* SOLVE THE APPLICATION */
942:   PetscCall(TaoSolve(tao));

944:   PetscCall(VecView(p, PETSC_VIEWER_STDOUT_WORLD));
945:   /* Free TAO data structures */
946:   PetscCall(TaoDestroy(&tao));
947:   PetscCall(VecDestroy(&user.vec_q));
948:   PetscCall(VecDestroy(&lowerb));
949:   PetscCall(VecDestroy(&upperb));
950:   PetscCall(VecDestroy(&p));
951:   PetscCall(DMDestroy(&user.dmgen));
952:   PetscCall(DMDestroy(&user.dmnet));
953:   PetscCall(DMDestroy(&user.dmpgrid));
954:   PetscCall(ISDestroy(&user.is_diff));
955:   PetscCall(ISDestroy(&user.is_alg));
956:   PetscCall(PetscFinalize());
957:   return 0;
958: }

960: /* ------------------------------------------------------------------ */
961: /*
962:    FormFunction - Evaluates the function and corresponding gradient.

964:    Input Parameters:
965:    tao - the Tao context
966:    X   - the input vector
967:    ptr - optional user-defined context, as set by TaoSetObjectiveAndGradient()

969:    Output Parameters:
970:    f   - the newly evaluated function
971: */
972: PetscErrorCode FormFunction(Tao tao, Vec P, PetscReal *f, void *ctx0)
973: {
974:   TS       ts;
975:   SNES     snes_alg;
976:   Userctx *ctx = (Userctx *)ctx0;
977:   Vec      X;
978:   Mat      J;
979:   /* sensitivity context */
980:   PetscScalar *x_ptr;
981:   PetscViewer  Xview, Ybusview;
982:   Vec          F_alg;
983:   Vec          Xdot;
984:   PetscInt     row_loc, col_loc;
985:   PetscScalar  val;

987:   PetscCall(VecGetArrayRead(P, (const PetscScalar **)&x_ptr));
988:   PG[0] = x_ptr[0];
989:   PG[1] = x_ptr[1];
990:   PG[2] = x_ptr[2];
991:   PetscCall(VecRestoreArrayRead(P, (const PetscScalar **)&x_ptr));

993:   ctx->stepnum = 0;

995:   PetscCall(VecZeroEntries(ctx->vec_q));

997:   /* Read initial voltage vector and Ybus */
998:   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, "X.bin", FILE_MODE_READ, &Xview));
999:   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, "Ybus.bin", FILE_MODE_READ, &Ybusview));

1001:   PetscCall(VecCreate(PETSC_COMM_WORLD, &ctx->V0));
1002:   PetscCall(VecSetSizes(ctx->V0, PETSC_DECIDE, ctx->neqs_net));
1003:   PetscCall(VecLoad(ctx->V0, Xview));

1005:   PetscCall(MatCreate(PETSC_COMM_WORLD, &ctx->Ybus));
1006:   PetscCall(MatSetSizes(ctx->Ybus, PETSC_DECIDE, PETSC_DECIDE, ctx->neqs_net, ctx->neqs_net));
1007:   PetscCall(MatSetType(ctx->Ybus, MATBAIJ));
1008:   /*  PetscCall(MatSetBlockSize(ctx->Ybus,2)); */
1009:   PetscCall(MatLoad(ctx->Ybus, Ybusview));

1011:   PetscCall(PetscViewerDestroy(&Xview));
1012:   PetscCall(PetscViewerDestroy(&Ybusview));

1014:   PetscCall(DMCreateGlobalVector(ctx->dmpgrid, &X));

1016:   PetscCall(MatCreate(PETSC_COMM_WORLD, &J));
1017:   PetscCall(MatSetSizes(J, PETSC_DECIDE, PETSC_DECIDE, ctx->neqs_pgrid, ctx->neqs_pgrid));
1018:   PetscCall(MatSetFromOptions(J));
1019:   PetscCall(PreallocateJacobian(J, ctx));

1021:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
1022:      Create timestepping solver context
1023:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
1024:   PetscCall(TSCreate(PETSC_COMM_WORLD, &ts));
1025:   PetscCall(TSSetProblemType(ts, TS_NONLINEAR));
1026:   PetscCall(TSSetType(ts, TSCN));
1027:   PetscCall(TSSetIFunction(ts, NULL, (TSIFunction)IFunction, ctx));
1028:   PetscCall(TSSetIJacobian(ts, J, J, (TSIJacobian)IJacobian, ctx));
1029:   PetscCall(TSSetApplicationContext(ts, ctx));

1031:   PetscCall(TSMonitorSet(ts, MonitorUpdateQ, ctx, NULL));
1032:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
1033:      Set initial conditions
1034:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
1035:   PetscCall(SetInitialGuess(X, ctx));

1037:   PetscCall(VecDuplicate(X, &F_alg));
1038:   PetscCall(SNESCreate(PETSC_COMM_WORLD, &snes_alg));
1039:   PetscCall(SNESSetFunction(snes_alg, F_alg, AlgFunction, ctx));
1040:   PetscCall(MatZeroEntries(J));
1041:   PetscCall(SNESSetJacobian(snes_alg, J, J, AlgJacobian, ctx));
1042:   PetscCall(SNESSetOptionsPrefix(snes_alg, "alg_"));
1043:   PetscCall(SNESSetFromOptions(snes_alg));
1044:   ctx->alg_flg = PETSC_TRUE;
1045:   /* Solve the algebraic equations */
1046:   PetscCall(SNESSolve(snes_alg, NULL, X));

1048:   /* Just to set up the Jacobian structure */
1049:   PetscCall(VecDuplicate(X, &Xdot));
1050:   PetscCall(IJacobian(ts, 0.0, X, Xdot, 0.0, J, J, ctx));
1051:   PetscCall(VecDestroy(&Xdot));

1053:   ctx->stepnum++;

1055:   PetscCall(TSSetTimeStep(ts, 0.01));
1056:   PetscCall(TSSetMaxTime(ts, ctx->tmax));
1057:   PetscCall(TSSetExactFinalTime(ts, TS_EXACTFINALTIME_MATCHSTEP));
1058:   PetscCall(TSSetFromOptions(ts));

1060:   /* Prefault period */
1061:   ctx->alg_flg = PETSC_FALSE;
1062:   PetscCall(TSSetTime(ts, 0.0));
1063:   PetscCall(TSSetMaxTime(ts, ctx->tfaulton));
1064:   PetscCall(TSSolve(ts, X));

1066:   /* Create the nonlinear solver for solving the algebraic system */
1067:   /* Note that although the algebraic system needs to be solved only for
1068:      Idq and V, we reuse the entire system including xgen. The xgen
1069:      variables are held constant by setting their residuals to 0 and
1070:      putting a 1 on the Jacobian diagonal for xgen rows
1071:   */
1072:   PetscCall(MatZeroEntries(J));

1074:   /* Apply disturbance - resistive fault at ctx->faultbus */
1075:   /* This is done by adding shunt conductance to the diagonal location
1076:      in the Ybus matrix */
1077:   row_loc = 2 * ctx->faultbus;
1078:   col_loc = 2 * ctx->faultbus + 1; /* Location for G */
1079:   val     = 1 / ctx->Rfault;
1080:   PetscCall(MatSetValues(ctx->Ybus, 1, &row_loc, 1, &col_loc, &val, ADD_VALUES));
1081:   row_loc = 2 * ctx->faultbus + 1;
1082:   col_loc = 2 * ctx->faultbus; /* Location for G */
1083:   val     = 1 / ctx->Rfault;
1084:   PetscCall(MatSetValues(ctx->Ybus, 1, &row_loc, 1, &col_loc, &val, ADD_VALUES));

1086:   PetscCall(MatAssemblyBegin(ctx->Ybus, MAT_FINAL_ASSEMBLY));
1087:   PetscCall(MatAssemblyEnd(ctx->Ybus, MAT_FINAL_ASSEMBLY));

1089:   ctx->alg_flg = PETSC_TRUE;
1090:   /* Solve the algebraic equations */
1091:   PetscCall(SNESSolve(snes_alg, NULL, X));

1093:   ctx->stepnum++;

1095:   /* Disturbance period */
1096:   ctx->alg_flg = PETSC_FALSE;
1097:   PetscCall(TSSetTime(ts, ctx->tfaulton));
1098:   PetscCall(TSSetMaxTime(ts, ctx->tfaultoff));
1099:   PetscCall(TSSolve(ts, X));

1101:   /* Remove the fault */
1102:   row_loc = 2 * ctx->faultbus;
1103:   col_loc = 2 * ctx->faultbus + 1;
1104:   val     = -1 / ctx->Rfault;
1105:   PetscCall(MatSetValues(ctx->Ybus, 1, &row_loc, 1, &col_loc, &val, ADD_VALUES));
1106:   row_loc = 2 * ctx->faultbus + 1;
1107:   col_loc = 2 * ctx->faultbus;
1108:   val     = -1 / ctx->Rfault;
1109:   PetscCall(MatSetValues(ctx->Ybus, 1, &row_loc, 1, &col_loc, &val, ADD_VALUES));

1111:   PetscCall(MatAssemblyBegin(ctx->Ybus, MAT_FINAL_ASSEMBLY));
1112:   PetscCall(MatAssemblyEnd(ctx->Ybus, MAT_FINAL_ASSEMBLY));

1114:   PetscCall(MatZeroEntries(J));

1116:   ctx->alg_flg = PETSC_TRUE;

1118:   /* Solve the algebraic equations */
1119:   PetscCall(SNESSolve(snes_alg, NULL, X));

1121:   ctx->stepnum++;

1123:   /* Post-disturbance period */
1124:   ctx->alg_flg = PETSC_TRUE;
1125:   PetscCall(TSSetTime(ts, ctx->tfaultoff));
1126:   PetscCall(TSSetMaxTime(ts, ctx->tmax));
1127:   PetscCall(TSSolve(ts, X));

1129:   PetscCall(VecGetArray(ctx->vec_q, &x_ptr));
1130:   *f = x_ptr[0];
1131:   PetscCall(VecRestoreArray(ctx->vec_q, &x_ptr));

1133:   PetscCall(MatDestroy(&ctx->Ybus));
1134:   PetscCall(VecDestroy(&ctx->V0));
1135:   PetscCall(SNESDestroy(&snes_alg));
1136:   PetscCall(VecDestroy(&F_alg));
1137:   PetscCall(MatDestroy(&J));
1138:   PetscCall(VecDestroy(&X));
1139:   PetscCall(TSDestroy(&ts));

1141:   return 0;
1142: }

1144: /*TEST

1146:   build:
1147:       requires: double !complex !defined(USE_64BIT_INDICES)

1149:    test:
1150:       args: -viewer_binary_skip_info -tao_monitor -tao_gttol .2
1151:       localrunfiles: petscoptions X.bin Ybus.bin

1153: TEST*/