Actual source code: ex73.c

  1: /*
  2: This example was derived from src/ksp/ksp/tutorials ex29.c

  4: Inhomogeneous Laplacian in 2D. Modeled by the partial differential equation

  6:    -div \rho grad u = f,  0 < x,y < 1,

  8: with forcing function

 10:    f = e^{-x^2/\nu} e^{-y^2/\nu}

 12: with Dirichlet boundary conditions

 14:    u = f(x,y) for x = 0, x = 1, y = 0, y = 1

 16: or pure Neumman boundary conditions.
 17: */

 19: static char help[] = "Solves 2D inhomogeneous Laplacian. Demonstrates using PCTelescopeSetCoarseDM functionality of PCTelescope via a DMShell\n\n";

 21: #include <petscdm.h>
 22: #include <petscdmda.h>
 23: #include <petscdmshell.h>
 24: #include <petscksp.h>

 26: PetscErrorCode ComputeMatrix_ShellDA(KSP, Mat, Mat, void *);
 27: PetscErrorCode ComputeMatrix_DMDA(DM, Mat, Mat, void *);
 28: PetscErrorCode ComputeRHS_DMDA(DM, Vec, void *);
 29: PetscErrorCode DMShellCreate_ShellDA(DM, DM *);
 30: PetscErrorCode DMFieldScatter_ShellDA(DM, Vec, ScatterMode, DM, Vec);
 31: PetscErrorCode DMStateScatter_ShellDA(DM, ScatterMode, DM);

 33: typedef enum {
 34:   DIRICHLET,
 35:   NEUMANN
 36: } BCType;

 38: typedef struct {
 39:   PetscReal rho;
 40:   PetscReal nu;
 41:   BCType    bcType;
 42:   MPI_Comm  comm;
 43: } UserContext;

 45: PetscErrorCode UserContextCreate(MPI_Comm comm, UserContext **ctx)
 46: {
 47:   UserContext *user;
 48:   const char  *bcTypes[2] = {"dirichlet", "neumann"};
 49:   PetscInt     bc;

 51:   PetscFunctionBeginUser;
 52:   PetscCall(PetscCalloc1(1, &user));
 53:   user->comm = comm;
 54:   PetscOptionsBegin(comm, "", "Options for the inhomogeneous Poisson equation", "DMqq");
 55:   user->rho = 1.0;
 56:   PetscCall(PetscOptionsReal("-rho", "The conductivity", "ex29.c", user->rho, &user->rho, NULL));
 57:   user->nu = 0.1;
 58:   PetscCall(PetscOptionsReal("-nu", "The width of the Gaussian source", "ex29.c", user->nu, &user->nu, NULL));
 59:   bc = (PetscInt)DIRICHLET;
 60:   PetscCall(PetscOptionsEList("-bc_type", "Type of boundary condition", "ex29.c", bcTypes, 2, bcTypes[0], &bc, NULL));
 61:   user->bcType = (BCType)bc;
 62:   PetscOptionsEnd();
 63:   *ctx = user;
 64:   PetscFunctionReturn(PETSC_SUCCESS);
 65: }

 67: PetscErrorCode CommCoarsen(MPI_Comm comm, PetscInt number, PetscSubcomm *p)
 68: {
 69:   PetscSubcomm psubcomm;

 71:   PetscFunctionBeginUser;
 72:   PetscCall(PetscSubcommCreate(comm, &psubcomm));
 73:   PetscCall(PetscSubcommSetNumber(psubcomm, number));
 74:   PetscCall(PetscSubcommSetType(psubcomm, PETSC_SUBCOMM_INTERLACED));
 75:   *p = psubcomm;
 76:   PetscFunctionReturn(PETSC_SUCCESS);
 77: }

 79: PetscErrorCode CommHierarchyCreate(MPI_Comm comm, PetscInt n, PetscInt number[], PetscSubcomm pscommlist[])
 80: {
 81:   PetscInt  k;
 82:   PetscBool view_hierarchy = PETSC_FALSE;

 84:   PetscFunctionBeginUser;
 85:   for (k = 0; k < n; k++) pscommlist[k] = NULL;

 87:   if (n < 1) PetscFunctionReturn(PETSC_SUCCESS);

 89:   PetscCall(CommCoarsen(comm, number[n - 1], &pscommlist[n - 1]));
 90:   for (k = n - 2; k >= 0; k--) {
 91:     MPI_Comm comm_k = PetscSubcommChild(pscommlist[k + 1]);
 92:     if (pscommlist[k + 1]->color == 0) PetscCall(CommCoarsen(comm_k, number[k], &pscommlist[k]));
 93:   }

 95:   PetscCall(PetscOptionsGetBool(NULL, NULL, "-view_hierarchy", &view_hierarchy, NULL));
 96:   if (view_hierarchy) {
 97:     PetscMPIInt size;

 99:     PetscCallMPI(MPI_Comm_size(comm, &size));
100:     PetscCall(PetscPrintf(comm, "level[%" PetscInt_FMT "] size %d\n", n, (int)size));
101:     for (k = n - 1; k >= 0; k--) {
102:       if (pscommlist[k]) {
103:         MPI_Comm comm_k = PetscSubcommChild(pscommlist[k]);

105:         if (pscommlist[k]->color == 0) {
106:           PetscCallMPI(MPI_Comm_size(comm_k, &size));
107:           PetscCall(PetscPrintf(comm_k, "level[%" PetscInt_FMT "] size %d\n", k, (int)size));
108:         }
109:       }
110:     }
111:   }
112:   PetscFunctionReturn(PETSC_SUCCESS);
113: }

115: /* taken from src/ksp/pc/impls/telescope/telescope_dmda.c */
116: static PetscErrorCode _DMDADetermineRankFromGlobalIJ_2d(PetscInt i, PetscInt j, PetscInt Mp, PetscInt Np, PetscInt start_i[], PetscInt start_j[], PetscInt span_i[], PetscInt span_j[], PetscMPIInt *_pi, PetscMPIInt *_pj, PetscMPIInt *rank_re)
117: {
118:   PetscInt pi, pj, n;

120:   PetscFunctionBeginUser;
121:   *rank_re = -1;
122:   pi = pj = -1;
123:   if (_pi) {
124:     for (n = 0; n < Mp; n++) {
125:       if ((i >= start_i[n]) && (i < start_i[n] + span_i[n])) {
126:         pi = n;
127:         break;
128:       }
129:     }
130:     PetscCheck(pi != -1, PETSC_COMM_SELF, PETSC_ERR_USER, "[dmda-ij] pi cannot be determined : range %" PetscInt_FMT ", val %" PetscInt_FMT, Mp, i);
131:     *_pi = (PetscMPIInt)pi;
132:   }

134:   if (_pj) {
135:     for (n = 0; n < Np; n++) {
136:       if ((j >= start_j[n]) && (j < start_j[n] + span_j[n])) {
137:         pj = n;
138:         break;
139:       }
140:     }
141:     PetscCheck(pj != -1, PETSC_COMM_SELF, PETSC_ERR_USER, "[dmda-ij] pj cannot be determined : range %" PetscInt_FMT ", val %" PetscInt_FMT, Np, j);
142:     *_pj = (PetscMPIInt)pj;
143:   }

145:   *rank_re = (PetscMPIInt)(pi + pj * Mp);
146:   PetscFunctionReturn(PETSC_SUCCESS);
147: }

149: /* taken from src/ksp/pc/impls/telescope/telescope_dmda.c */
150: static PetscErrorCode _DMDADetermineGlobalS0_2d(PetscMPIInt rank_re, PetscInt Mp_re, PetscInt Np_re, PetscInt range_i_re[], PetscInt range_j_re[], PetscInt *s0)
151: {
152:   PetscInt    i, j, start_IJ = 0;
153:   PetscMPIInt rank_ij;

155:   PetscFunctionBeginUser;
156:   *s0 = -1;
157:   for (j = 0; j < Np_re; j++) {
158:     for (i = 0; i < Mp_re; i++) {
159:       rank_ij = (PetscMPIInt)(i + j * Mp_re);
160:       if (rank_ij < rank_re) start_IJ += range_i_re[i] * range_j_re[j];
161:     }
162:   }
163:   *s0 = start_IJ;
164:   PetscFunctionReturn(PETSC_SUCCESS);
165: }

167: /* adapted from src/ksp/pc/impls/telescope/telescope_dmda.c */
168: static PetscErrorCode DMDACreatePermutation_2d(DM dmrepart, DM dmf, Mat *mat)
169: {
170:   PetscInt        k, sum, Mp_re = 0, Np_re = 0;
171:   PetscInt        nx, ny, sr, er, Mr, ndof;
172:   PetscInt        i, j, location, startI[2], endI[2], lenI[2];
173:   const PetscInt *_range_i_re = NULL, *_range_j_re = NULL;
174:   PetscInt       *range_i_re, *range_j_re;
175:   PetscInt       *start_i_re, *start_j_re;
176:   MPI_Comm        comm;
177:   Vec             V;
178:   Mat             Pscalar;

180:   PetscFunctionBeginUser;
181:   PetscCall(PetscInfo(dmf, "setting up the permutation matrix (DMDA-2D)\n"));
182:   PetscCall(PetscObjectGetComm((PetscObject)dmf, &comm));

184:   _range_i_re = _range_j_re = NULL;
185:   /* Create DMDA on the child communicator */
186:   if (dmrepart) {
187:     PetscCall(DMDAGetInfo(dmrepart, NULL, NULL, NULL, NULL, &Mp_re, &Np_re, NULL, NULL, NULL, NULL, NULL, NULL, NULL));
188:     PetscCall(DMDAGetOwnershipRanges(dmrepart, &_range_i_re, &_range_j_re, NULL));
189:   }

191:   /* note - assume rank 0 always participates */
192:   PetscCallMPI(MPI_Bcast(&Mp_re, 1, MPIU_INT, 0, comm));
193:   PetscCallMPI(MPI_Bcast(&Np_re, 1, MPIU_INT, 0, comm));

195:   PetscCall(PetscCalloc1(Mp_re, &range_i_re));
196:   PetscCall(PetscCalloc1(Np_re, &range_j_re));

198:   if (_range_i_re) PetscCall(PetscArraycpy(range_i_re, _range_i_re, Mp_re));
199:   if (_range_j_re) PetscCall(PetscArraycpy(range_j_re, _range_j_re, Np_re));

201:   PetscCallMPI(MPI_Bcast(range_i_re, Mp_re, MPIU_INT, 0, comm));
202:   PetscCallMPI(MPI_Bcast(range_j_re, Np_re, MPIU_INT, 0, comm));

204:   PetscCall(PetscMalloc1(Mp_re, &start_i_re));
205:   PetscCall(PetscMalloc1(Np_re, &start_j_re));

207:   sum = 0;
208:   for (k = 0; k < Mp_re; k++) {
209:     start_i_re[k] = sum;
210:     sum += range_i_re[k];
211:   }

213:   sum = 0;
214:   for (k = 0; k < Np_re; k++) {
215:     start_j_re[k] = sum;
216:     sum += range_j_re[k];
217:   }

219:   /* Create permutation */
220:   PetscCall(DMDAGetInfo(dmf, NULL, &nx, &ny, NULL, NULL, NULL, NULL, &ndof, NULL, NULL, NULL, NULL, NULL));
221:   PetscCall(DMGetGlobalVector(dmf, &V));
222:   PetscCall(VecGetSize(V, &Mr));
223:   PetscCall(VecGetOwnershipRange(V, &sr, &er));
224:   PetscCall(DMRestoreGlobalVector(dmf, &V));
225:   sr = sr / ndof;
226:   er = er / ndof;
227:   Mr = Mr / ndof;

229:   PetscCall(MatCreate(comm, &Pscalar));
230:   PetscCall(MatSetSizes(Pscalar, (er - sr), (er - sr), Mr, Mr));
231:   PetscCall(MatSetType(Pscalar, MATAIJ));
232:   PetscCall(MatSeqAIJSetPreallocation(Pscalar, 1, NULL));
233:   PetscCall(MatMPIAIJSetPreallocation(Pscalar, 1, NULL, 1, NULL));

235:   PetscCall(DMDAGetCorners(dmf, NULL, NULL, NULL, &lenI[0], &lenI[1], NULL));
236:   PetscCall(DMDAGetCorners(dmf, &startI[0], &startI[1], NULL, &endI[0], &endI[1], NULL));
237:   endI[0] += startI[0];
238:   endI[1] += startI[1];

240:   for (j = startI[1]; j < endI[1]; j++) {
241:     for (i = startI[0]; i < endI[0]; i++) {
242:       PetscMPIInt rank_ijk_re, rank_reI[] = {0, 0};
243:       PetscInt    s0_re;
244:       PetscInt    ii, jj, local_ijk_re, mapped_ijk;
245:       PetscInt    lenI_re[] = {0, 0};

247:       location = (i - startI[0]) + (j - startI[1]) * lenI[0];
248:       PetscCall(_DMDADetermineRankFromGlobalIJ_2d(i, j, Mp_re, Np_re, start_i_re, start_j_re, range_i_re, range_j_re, &rank_reI[0], &rank_reI[1], &rank_ijk_re));

250:       PetscCall(_DMDADetermineGlobalS0_2d(rank_ijk_re, Mp_re, Np_re, range_i_re, range_j_re, &s0_re));

252:       ii = i - start_i_re[rank_reI[0]];
253:       PetscCheck(ii >= 0, PETSC_COMM_SELF, PETSC_ERR_USER, "[dmdarepart-perm2d] index error ii");
254:       jj = j - start_j_re[rank_reI[1]];
255:       PetscCheck(jj >= 0, PETSC_COMM_SELF, PETSC_ERR_USER, "[dmdarepart-perm2d] index error jj");

257:       lenI_re[0]   = range_i_re[rank_reI[0]];
258:       lenI_re[1]   = range_j_re[rank_reI[1]];
259:       local_ijk_re = ii + jj * lenI_re[0];
260:       mapped_ijk   = s0_re + local_ijk_re;
261:       PetscCall(MatSetValue(Pscalar, sr + location, mapped_ijk, 1.0, INSERT_VALUES));
262:     }
263:   }
264:   PetscCall(MatAssemblyBegin(Pscalar, MAT_FINAL_ASSEMBLY));
265:   PetscCall(MatAssemblyEnd(Pscalar, MAT_FINAL_ASSEMBLY));

267:   *mat = Pscalar;

269:   PetscCall(PetscFree(range_i_re));
270:   PetscCall(PetscFree(range_j_re));
271:   PetscCall(PetscFree(start_i_re));
272:   PetscCall(PetscFree(start_j_re));
273:   PetscFunctionReturn(PETSC_SUCCESS);
274: }

276: /* adapted from src/ksp/pc/impls/telescope/telescope_dmda.c */
277: static PetscErrorCode PCTelescopeSetUp_dmda_scatters(DM dmf, DM dmc)
278: {
279:   Vec        xred, yred, xtmp, x, xp;
280:   VecScatter scatter;
281:   IS         isin;
282:   PetscInt   m, bs, st, ed;
283:   MPI_Comm   comm;
284:   VecType    vectype;

286:   PetscFunctionBeginUser;
287:   PetscCall(PetscObjectGetComm((PetscObject)dmf, &comm));
288:   PetscCall(DMCreateGlobalVector(dmf, &x));
289:   PetscCall(VecGetBlockSize(x, &bs));
290:   PetscCall(VecGetType(x, &vectype));

292:   /* cannot use VecDuplicate as xp is already composed with dmf */
293:   /*PetscCall(VecDuplicate(x,&xp));*/
294:   {
295:     PetscInt m, M;

297:     PetscCall(VecGetSize(x, &M));
298:     PetscCall(VecGetLocalSize(x, &m));
299:     PetscCall(VecCreate(comm, &xp));
300:     PetscCall(VecSetSizes(xp, m, M));
301:     PetscCall(VecSetBlockSize(xp, bs));
302:     PetscCall(VecSetType(xp, vectype));
303:   }

305:   m    = 0;
306:   xred = NULL;
307:   yred = NULL;
308:   if (dmc) {
309:     PetscCall(DMCreateGlobalVector(dmc, &xred));
310:     PetscCall(VecDuplicate(xred, &yred));
311:     PetscCall(VecGetOwnershipRange(xred, &st, &ed));
312:     PetscCall(ISCreateStride(comm, ed - st, st, 1, &isin));
313:     PetscCall(VecGetLocalSize(xred, &m));
314:   } else {
315:     PetscCall(VecGetOwnershipRange(x, &st, &ed));
316:     PetscCall(ISCreateStride(comm, 0, st, 1, &isin));
317:   }
318:   PetscCall(ISSetBlockSize(isin, bs));
319:   PetscCall(VecCreate(comm, &xtmp));
320:   PetscCall(VecSetSizes(xtmp, m, PETSC_DECIDE));
321:   PetscCall(VecSetBlockSize(xtmp, bs));
322:   PetscCall(VecSetType(xtmp, vectype));
323:   PetscCall(VecScatterCreate(x, isin, xtmp, NULL, &scatter));

325:   PetscCall(PetscObjectCompose((PetscObject)dmf, "isin", (PetscObject)isin));
326:   PetscCall(PetscObjectCompose((PetscObject)dmf, "scatter", (PetscObject)scatter));
327:   PetscCall(PetscObjectCompose((PetscObject)dmf, "xtmp", (PetscObject)xtmp));
328:   PetscCall(PetscObjectCompose((PetscObject)dmf, "xp", (PetscObject)xp));

330:   PetscCall(VecDestroy(&xred));
331:   PetscCall(VecDestroy(&yred));
332:   PetscCall(VecDestroy(&x));
333:   PetscFunctionReturn(PETSC_SUCCESS);
334: }

336: PetscErrorCode DMCreateMatrix_ShellDA(DM dm, Mat *A)
337: {
338:   DM           da;
339:   MPI_Comm     comm;
340:   PetscMPIInt  size;
341:   UserContext *ctx = NULL;
342:   PetscInt     M, N;

344:   PetscFunctionBeginUser;
345:   PetscCall(DMShellGetContext(dm, &da));
346:   PetscCall(PetscObjectGetComm((PetscObject)da, &comm));
347:   PetscCallMPI(MPI_Comm_size(comm, &size));
348:   PetscCall(DMCreateMatrix(da, A));
349:   PetscCall(MatGetSize(*A, &M, &N));
350:   PetscCall(PetscPrintf(comm, "[size %" PetscInt_FMT "] DMCreateMatrix_ShellDA (%" PetscInt_FMT " x %" PetscInt_FMT ")\n", (PetscInt)size, M, N));

352:   PetscCall(DMGetApplicationContext(dm, &ctx));
353:   if (ctx->bcType == NEUMANN) {
354:     MatNullSpace nullspace = NULL;
355:     PetscCall(PetscPrintf(comm, "[size %" PetscInt_FMT "] DMCreateMatrix_ShellDA: using neumann bcs\n", (PetscInt)size));

357:     PetscCall(MatGetNullSpace(*A, &nullspace));
358:     if (!nullspace) {
359:       PetscCall(PetscPrintf(comm, "[size %" PetscInt_FMT "] DMCreateMatrix_ShellDA: operator does not have nullspace - attaching\n", (PetscInt)size));
360:       PetscCall(MatNullSpaceCreate(comm, PETSC_TRUE, 0, 0, &nullspace));
361:       PetscCall(MatSetNullSpace(*A, nullspace));
362:       PetscCall(MatNullSpaceDestroy(&nullspace));
363:     } else {
364:       PetscCall(PetscPrintf(comm, "[size %" PetscInt_FMT "] DMCreateMatrix_ShellDA: operator already has a nullspace\n", (PetscInt)size));
365:     }
366:   }
367:   PetscFunctionReturn(PETSC_SUCCESS);
368: }

370: PetscErrorCode DMCreateGlobalVector_ShellDA(DM dm, Vec *x)
371: {
372:   DM da;

374:   PetscFunctionBeginUser;
375:   PetscCall(DMShellGetContext(dm, &da));
376:   PetscCall(DMCreateGlobalVector(da, x));
377:   PetscCall(VecSetDM(*x, dm));
378:   PetscFunctionReturn(PETSC_SUCCESS);
379: }

381: PetscErrorCode DMCreateLocalVector_ShellDA(DM dm, Vec *x)
382: {
383:   DM da;

385:   PetscFunctionBeginUser;
386:   PetscCall(DMShellGetContext(dm, &da));
387:   PetscCall(DMCreateLocalVector(da, x));
388:   PetscCall(VecSetDM(*x, dm));
389:   PetscFunctionReturn(PETSC_SUCCESS);
390: }

392: PetscErrorCode DMCoarsen_ShellDA(DM dm, MPI_Comm comm, DM *dmc)
393: {
394:   PetscFunctionBeginUser;
395:   *dmc = NULL;
396:   PetscCall(DMGetCoarseDM(dm, dmc));
397:   if (!*dmc) {
398:     SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "The coarse DM should never be NULL. The DM hierarchy should have already been defined");
399:   } else {
400:     PetscCall(PetscObjectReference((PetscObject)*dmc));
401:   }
402:   PetscFunctionReturn(PETSC_SUCCESS);
403: }

405: PetscErrorCode DMCreateInterpolation_ShellDA(DM dm1, DM dm2, Mat *mat, Vec *vec)
406: {
407:   DM da1, da2;

409:   PetscFunctionBeginUser;
410:   PetscCall(DMShellGetContext(dm1, &da1));
411:   PetscCall(DMShellGetContext(dm2, &da2));
412:   PetscCall(DMCreateInterpolation(da1, da2, mat, vec));
413:   PetscFunctionReturn(PETSC_SUCCESS);
414: }

416: PetscErrorCode DMShellDASetUp_TelescopeDMScatter(DM dmf_shell, DM dmc_shell)
417: {
418:   Mat P   = NULL;
419:   DM  dmf = NULL, dmc = NULL;

421:   PetscFunctionBeginUser;
422:   PetscCall(DMShellGetContext(dmf_shell, &dmf));
423:   if (dmc_shell) PetscCall(DMShellGetContext(dmc_shell, &dmc));
424:   PetscCall(DMDACreatePermutation_2d(dmc, dmf, &P));
425:   PetscCall(PetscObjectCompose((PetscObject)dmf, "P", (PetscObject)P));
426:   PetscCall(PCTelescopeSetUp_dmda_scatters(dmf, dmc));
427:   PetscCall(PetscObjectComposeFunction((PetscObject)dmf_shell, "PCTelescopeFieldScatter", DMFieldScatter_ShellDA));
428:   PetscCall(PetscObjectComposeFunction((PetscObject)dmf_shell, "PCTelescopeStateScatter", DMStateScatter_ShellDA));
429:   PetscFunctionReturn(PETSC_SUCCESS);
430: }

432: PetscErrorCode DMShellDAFieldScatter_Forward(DM dmf, Vec x, DM dmc, Vec xc)
433: {
434:   Mat                P  = NULL;
435:   Vec                xp = NULL, xtmp = NULL;
436:   VecScatter         scatter = NULL;
437:   const PetscScalar *x_array;
438:   PetscInt           i, st, ed;

440:   PetscFunctionBeginUser;
441:   PetscCall(PetscObjectQuery((PetscObject)dmf, "P", (PetscObject *)&P));
442:   PetscCall(PetscObjectQuery((PetscObject)dmf, "xp", (PetscObject *)&xp));
443:   PetscCall(PetscObjectQuery((PetscObject)dmf, "scatter", (PetscObject *)&scatter));
444:   PetscCall(PetscObjectQuery((PetscObject)dmf, "xtmp", (PetscObject *)&xtmp));
445:   PetscCheck(P, PETSC_COMM_SELF, PETSC_ERR_USER, "Require a permutation matrix (\"P\")to be composed with the parent (fine) DM");
446:   PetscCheck(xp, PETSC_COMM_SELF, PETSC_ERR_USER, "Require \"xp\" to be composed with the parent (fine) DM");
447:   PetscCheck(scatter, PETSC_COMM_SELF, PETSC_ERR_USER, "Require \"scatter\" to be composed with the parent (fine) DM");
448:   PetscCheck(xtmp, PETSC_COMM_SELF, PETSC_ERR_USER, "Require \"xtmp\" to be composed with the parent (fine) DM");

450:   PetscCall(MatMultTranspose(P, x, xp));

452:   /* pull in vector x->xtmp */
453:   PetscCall(VecScatterBegin(scatter, xp, xtmp, INSERT_VALUES, SCATTER_FORWARD));
454:   PetscCall(VecScatterEnd(scatter, xp, xtmp, INSERT_VALUES, SCATTER_FORWARD));

456:   /* copy vector entries into xred */
457:   PetscCall(VecGetArrayRead(xtmp, &x_array));
458:   if (xc) {
459:     PetscScalar *LA_xred;
460:     PetscCall(VecGetOwnershipRange(xc, &st, &ed));

462:     PetscCall(VecGetArray(xc, &LA_xred));
463:     for (i = 0; i < ed - st; i++) LA_xred[i] = x_array[i];
464:     PetscCall(VecRestoreArray(xc, &LA_xred));
465:   }
466:   PetscCall(VecRestoreArrayRead(xtmp, &x_array));
467:   PetscFunctionReturn(PETSC_SUCCESS);
468: }

470: PetscErrorCode DMShellDAFieldScatter_Reverse(DM dmf, Vec y, DM dmc, Vec yc)
471: {
472:   Mat          P  = NULL;
473:   Vec          xp = NULL, xtmp = NULL;
474:   VecScatter   scatter = NULL;
475:   PetscScalar *array;
476:   PetscInt     i, st, ed;

478:   PetscFunctionBeginUser;
479:   PetscCall(PetscObjectQuery((PetscObject)dmf, "P", (PetscObject *)&P));
480:   PetscCall(PetscObjectQuery((PetscObject)dmf, "xp", (PetscObject *)&xp));
481:   PetscCall(PetscObjectQuery((PetscObject)dmf, "scatter", (PetscObject *)&scatter));
482:   PetscCall(PetscObjectQuery((PetscObject)dmf, "xtmp", (PetscObject *)&xtmp));

484:   PetscCheck(P, PETSC_COMM_SELF, PETSC_ERR_USER, "Require a permutation matrix (\"P\")to be composed with the parent (fine) DM");
485:   PetscCheck(xp, PETSC_COMM_SELF, PETSC_ERR_USER, "Require \"xp\" to be composed with the parent (fine) DM");
486:   PetscCheck(scatter, PETSC_COMM_SELF, PETSC_ERR_USER, "Require \"scatter\" to be composed with the parent (fine) DM");
487:   PetscCheck(xtmp, PETSC_COMM_SELF, PETSC_ERR_USER, "Require \"xtmp\" to be composed with the parent (fine) DM");

489:   /* return vector */
490:   PetscCall(VecGetArray(xtmp, &array));
491:   if (yc) {
492:     const PetscScalar *LA_yred;
493:     PetscCall(VecGetOwnershipRange(yc, &st, &ed));
494:     PetscCall(VecGetArrayRead(yc, &LA_yred));
495:     for (i = 0; i < ed - st; i++) array[i] = LA_yred[i];
496:     PetscCall(VecRestoreArrayRead(yc, &LA_yred));
497:   }
498:   PetscCall(VecRestoreArray(xtmp, &array));
499:   PetscCall(VecScatterBegin(scatter, xtmp, xp, INSERT_VALUES, SCATTER_REVERSE));
500:   PetscCall(VecScatterEnd(scatter, xtmp, xp, INSERT_VALUES, SCATTER_REVERSE));
501:   PetscCall(MatMult(P, xp, y));
502:   PetscFunctionReturn(PETSC_SUCCESS);
503: }

505: PetscErrorCode DMFieldScatter_ShellDA(DM dmf_shell, Vec x, ScatterMode mode, DM dmc_shell, Vec xc)
506: {
507:   DM dmf = NULL, dmc = NULL;

509:   PetscFunctionBeginUser;
510:   PetscCall(DMShellGetContext(dmf_shell, &dmf));
511:   if (dmc_shell) PetscCall(DMShellGetContext(dmc_shell, &dmc));
512:   if (mode == SCATTER_FORWARD) {
513:     PetscCall(DMShellDAFieldScatter_Forward(dmf, x, dmc, xc));
514:   } else if (mode == SCATTER_REVERSE) {
515:     PetscCall(DMShellDAFieldScatter_Reverse(dmf, x, dmc, xc));
516:   } else SETERRQ(PetscObjectComm((PetscObject)dmf_shell), PETSC_ERR_SUP, "Only mode = SCATTER_FORWARD, SCATTER_REVERSE supported");
517:   PetscFunctionReturn(PETSC_SUCCESS);
518: }

520: PetscErrorCode DMStateScatter_ShellDA(DM dmf_shell, ScatterMode mode, DM dmc_shell)
521: {
522:   PetscMPIInt size_f = 0, size_c = 0;

524:   PetscFunctionBeginUser;
525:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dmf_shell), &size_f));
526:   if (dmc_shell) PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dmc_shell), &size_c));
527:   if (mode == SCATTER_FORWARD) {
528:     PetscCall(PetscPrintf(PetscObjectComm((PetscObject)dmf_shell), "User supplied state scatter (fine [size %d]-> coarse [size %d])\n", (int)size_f, (int)size_c));
529:   } else if (mode == SCATTER_REVERSE) {
530:   } else SETERRQ(PetscObjectComm((PetscObject)dmf_shell), PETSC_ERR_SUP, "Only mode = SCATTER_FORWARD, SCATTER_REVERSE supported");
531:   PetscFunctionReturn(PETSC_SUCCESS);
532: }

534: PetscErrorCode DMShellCreate_ShellDA(DM da, DM *dms)
535: {
536:   PetscFunctionBeginUser;
537:   if (da) {
538:     PetscCall(DMShellCreate(PetscObjectComm((PetscObject)da), dms));
539:     PetscCall(DMShellSetContext(*dms, da));
540:     PetscCall(DMShellSetCreateGlobalVector(*dms, DMCreateGlobalVector_ShellDA));
541:     PetscCall(DMShellSetCreateLocalVector(*dms, DMCreateLocalVector_ShellDA));
542:     PetscCall(DMShellSetCreateMatrix(*dms, DMCreateMatrix_ShellDA));
543:     PetscCall(DMShellSetCoarsen(*dms, DMCoarsen_ShellDA));
544:     PetscCall(DMShellSetCreateInterpolation(*dms, DMCreateInterpolation_ShellDA));
545:   } else {
546:     *dms = NULL;
547:   }
548:   PetscFunctionReturn(PETSC_SUCCESS);
549: }

551: PetscErrorCode DMDestroyShellDMDA(DM *_dm)
552: {
553:   DM dm, da = NULL;

555:   PetscFunctionBeginUser;
556:   if (!_dm) PetscFunctionReturn(PETSC_SUCCESS);
557:   dm = *_dm;
558:   if (!dm) PetscFunctionReturn(PETSC_SUCCESS);

560:   PetscCall(DMShellGetContext(dm, &da));
561:   if (da) {
562:     Vec        vec;
563:     VecScatter scatter = NULL;
564:     IS         is      = NULL;
565:     Mat        P       = NULL;

567:     PetscCall(PetscObjectQuery((PetscObject)da, "P", (PetscObject *)&P));
568:     PetscCall(MatDestroy(&P));

570:     vec = NULL;
571:     PetscCall(PetscObjectQuery((PetscObject)da, "xp", (PetscObject *)&vec));
572:     PetscCall(VecDestroy(&vec));

574:     PetscCall(PetscObjectQuery((PetscObject)da, "scatter", (PetscObject *)&scatter));
575:     PetscCall(VecScatterDestroy(&scatter));

577:     vec = NULL;
578:     PetscCall(PetscObjectQuery((PetscObject)da, "xtmp", (PetscObject *)&vec));
579:     PetscCall(VecDestroy(&vec));

581:     PetscCall(PetscObjectQuery((PetscObject)da, "isin", (PetscObject *)&is));
582:     PetscCall(ISDestroy(&is));

584:     PetscCall(DMDestroy(&da));
585:   }
586:   PetscCall(PetscObjectComposeFunction((PetscObject)dm, "PCTelescopeFieldScatter", NULL));
587:   PetscCall(PetscObjectComposeFunction((PetscObject)dm, "PCTelescopeStateScatter", NULL));
588:   PetscCall(DMDestroy(&dm));
589:   *_dm = NULL;
590:   PetscFunctionReturn(PETSC_SUCCESS);
591: }

593: PetscErrorCode HierarchyCreate_Basic(DM *dm_f, DM *dm_c, UserContext *ctx)
594: {
595:   DM          dm, dmc, dm_shell, dmc_shell;
596:   PetscMPIInt rank;

598:   PetscFunctionBeginUser;
599:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
600:   PetscCall(DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_STAR, 17, 17, PETSC_DECIDE, PETSC_DECIDE, 1, 1, 0, 0, &dm));
601:   PetscCall(DMSetFromOptions(dm));
602:   PetscCall(DMSetUp(dm));
603:   PetscCall(DMDASetUniformCoordinates(dm, 0, 1, 0, 1, 0, 0));
604:   PetscCall(DMDASetFieldName(dm, 0, "Pressure"));
605:   PetscCall(DMShellCreate_ShellDA(dm, &dm_shell));
606:   PetscCall(DMSetApplicationContext(dm_shell, ctx));

608:   dmc       = NULL;
609:   dmc_shell = NULL;
610:   if (rank == 0) {
611:     PetscCall(DMDACreate2d(PETSC_COMM_SELF, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_STAR, 17, 17, PETSC_DECIDE, PETSC_DECIDE, 1, 1, 0, 0, &dmc));
612:     PetscCall(DMSetFromOptions(dmc));
613:     PetscCall(DMSetUp(dmc));
614:     PetscCall(DMDASetUniformCoordinates(dmc, 0, 1, 0, 1, 0, 0));
615:     PetscCall(DMDASetFieldName(dmc, 0, "Pressure"));
616:     PetscCall(DMShellCreate_ShellDA(dmc, &dmc_shell));
617:     PetscCall(DMSetApplicationContext(dmc_shell, ctx));
618:   }

620:   PetscCall(DMSetCoarseDM(dm_shell, dmc_shell));
621:   PetscCall(DMShellDASetUp_TelescopeDMScatter(dm_shell, dmc_shell));

623:   *dm_f = dm_shell;
624:   *dm_c = dmc_shell;
625:   PetscFunctionReturn(PETSC_SUCCESS);
626: }

628: PetscErrorCode HierarchyCreate(PetscInt *_nd, PetscInt *_nref, MPI_Comm **_cl, DM **_dl)
629: {
630:   PetscInt      d, k, ndecomps, ncoarsen, found, nx;
631:   PetscInt      levelrefs, *number;
632:   PetscSubcomm *pscommlist;
633:   MPI_Comm     *commlist;
634:   DM           *dalist, *dmlist;
635:   PetscBool     set;

637:   PetscFunctionBeginUser;
638:   ndecomps = 1;
639:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-ndecomps", &ndecomps, NULL));
640:   ncoarsen = ndecomps - 1;
641:   PetscCheck(ncoarsen >= 0, PETSC_COMM_WORLD, PETSC_ERR_USER, "-ndecomps must be >= 1");

643:   levelrefs = 2;
644:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-level_nrefs", &levelrefs, NULL));
645:   PetscCall(PetscMalloc1(ncoarsen + 1, &number));
646:   for (k = 0; k < ncoarsen + 1; k++) number[k] = 2;
647:   found = ncoarsen;
648:   set   = PETSC_FALSE;
649:   PetscCall(PetscOptionsGetIntArray(NULL, NULL, "-level_comm_red_factor", number, &found, &set));
650:   if (set) PetscCheck(found == ncoarsen, PETSC_COMM_WORLD, PETSC_ERR_USER, "Expected %" PetscInt_FMT " values for -level_comm_red_factor. Found %" PetscInt_FMT, ncoarsen, found);

652:   PetscCall(PetscMalloc1(ncoarsen + 1, &pscommlist));
653:   for (k = 0; k < ncoarsen + 1; k++) pscommlist[k] = NULL;

655:   PetscCall(PetscMalloc1(ndecomps, &commlist));
656:   for (k = 0; k < ndecomps; k++) commlist[k] = MPI_COMM_NULL;
657:   PetscCall(PetscMalloc1(ndecomps * levelrefs, &dalist));
658:   PetscCall(PetscMalloc1(ndecomps * levelrefs, &dmlist));
659:   for (k = 0; k < ndecomps * levelrefs; k++) {
660:     dalist[k] = NULL;
661:     dmlist[k] = NULL;
662:   }

664:   PetscCall(CommHierarchyCreate(PETSC_COMM_WORLD, ncoarsen, number, pscommlist));
665:   for (k = 0; k < ncoarsen; k++) {
666:     if (pscommlist[k]) {
667:       MPI_Comm comm_k = PetscSubcommChild(pscommlist[k]);
668:       if (pscommlist[k]->color == 0) PetscCall(PetscCommDuplicate(comm_k, &commlist[k], NULL));
669:     }
670:   }
671:   PetscCall(PetscCommDuplicate(PETSC_COMM_WORLD, &commlist[ndecomps - 1], NULL));

673:   for (k = 0; k < ncoarsen; k++) {
674:     if (pscommlist[k]) PetscCall(PetscSubcommDestroy(&pscommlist[k]));
675:   }

677:   nx = 17;
678:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &nx, NULL));
679:   for (d = 0; d < ndecomps; d++) {
680:     DM   dmroot = NULL;
681:     char name[PETSC_MAX_PATH_LEN];

683:     if (commlist[d] != MPI_COMM_NULL) {
684:       PetscCall(DMDACreate2d(commlist[d], DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_STAR, nx, nx, PETSC_DECIDE, PETSC_DECIDE, 1, 1, 0, 0, &dmroot));
685:       PetscCall(DMSetUp(dmroot));
686:       PetscCall(DMDASetUniformCoordinates(dmroot, 0, 1, 0, 1, 0, 0));
687:       PetscCall(DMDASetFieldName(dmroot, 0, "Pressure"));
688:       PetscCall(PetscSNPrintf(name, PETSC_MAX_PATH_LEN - 1, "root-decomp-%" PetscInt_FMT, d));
689:       PetscCall(PetscObjectSetName((PetscObject)dmroot, name));
690:       /*PetscCall(DMView(dmroot,PETSC_VIEWER_STDOUT_(commlist[d])));*/
691:     }

693:     dalist[d * levelrefs + 0] = dmroot;
694:     for (k = 1; k < levelrefs; k++) {
695:       DM dmref = NULL;

697:       if (commlist[d] != MPI_COMM_NULL) {
698:         PetscCall(DMRefine(dalist[d * levelrefs + (k - 1)], MPI_COMM_NULL, &dmref));
699:         PetscCall(PetscSNPrintf(name, PETSC_MAX_PATH_LEN - 1, "ref%" PetscInt_FMT "-decomp-%" PetscInt_FMT, k, d));
700:         PetscCall(PetscObjectSetName((PetscObject)dmref, name));
701:         PetscCall(DMDAGetInfo(dmref, NULL, &nx, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL));
702:         /*PetscCall(DMView(dmref,PETSC_VIEWER_STDOUT_(commlist[d])));*/
703:       }
704:       dalist[d * levelrefs + k] = dmref;
705:     }
706:     PetscCall(MPIU_Allreduce(MPI_IN_PLACE, &nx, 1, MPIU_INT, MPI_MAX, PETSC_COMM_WORLD));
707:   }

709:   /* create the hierarchy of DMShell's */
710:   for (d = 0; d < ndecomps; d++) {
711:     char name[PETSC_MAX_PATH_LEN];

713:     UserContext *ctx = NULL;
714:     if (commlist[d] != MPI_COMM_NULL) {
715:       PetscCall(UserContextCreate(commlist[d], &ctx));
716:       for (k = 0; k < levelrefs; k++) {
717:         PetscCall(DMShellCreate_ShellDA(dalist[d * levelrefs + k], &dmlist[d * levelrefs + k]));
718:         PetscCall(DMSetApplicationContext(dmlist[d * levelrefs + k], ctx));
719:         PetscCall(PetscSNPrintf(name, PETSC_MAX_PATH_LEN - 1, "level%" PetscInt_FMT "-decomp-%" PetscInt_FMT, k, d));
720:         PetscCall(PetscObjectSetName((PetscObject)dmlist[d * levelrefs + k], name));
721:       }
722:     }
723:   }

725:   /* set all the coarse DMs */
726:   for (k = 1; k < ndecomps * levelrefs; k++) { /* skip first DM as it doesn't have a coarse representation */
727:     DM dmfine = NULL, dmcoarse = NULL;

729:     dmfine   = dmlist[k];
730:     dmcoarse = dmlist[k - 1];
731:     if (dmfine) PetscCall(DMSetCoarseDM(dmfine, dmcoarse));
732:   }

734:   /* do special setup on the fine DM coupling different decompositions */
735:   for (d = 1; d < ndecomps; d++) { /* skip first decomposition as it doesn't have a coarse representation */
736:     DM dmfine = NULL, dmcoarse = NULL;

738:     dmfine   = dmlist[d * levelrefs + 0];
739:     dmcoarse = dmlist[(d - 1) * levelrefs + (levelrefs - 1)];
740:     if (dmfine) PetscCall(DMShellDASetUp_TelescopeDMScatter(dmfine, dmcoarse));
741:   }

743:   PetscCall(PetscFree(number));
744:   for (k = 0; k < ncoarsen; k++) PetscCall(PetscSubcommDestroy(&pscommlist[k]));
745:   PetscCall(PetscFree(pscommlist));

747:   if (_nd) *_nd = ndecomps;
748:   if (_nref) *_nref = levelrefs;
749:   if (_cl) {
750:     *_cl = commlist;
751:   } else {
752:     for (k = 0; k < ndecomps; k++) {
753:       if (commlist[k] != MPI_COMM_NULL) PetscCall(PetscCommDestroy(&commlist[k]));
754:     }
755:     PetscCall(PetscFree(commlist));
756:   }
757:   if (_dl) {
758:     *_dl = dmlist;
759:     PetscCall(PetscFree(dalist));
760:   } else {
761:     for (k = 0; k < ndecomps * levelrefs; k++) {
762:       PetscCall(DMDestroy(&dmlist[k]));
763:       PetscCall(DMDestroy(&dalist[k]));
764:     }
765:     PetscCall(PetscFree(dmlist));
766:     PetscCall(PetscFree(dalist));
767:   }
768:   PetscFunctionReturn(PETSC_SUCCESS);
769: }

771: PetscErrorCode test_hierarchy(void)
772: {
773:   PetscInt  d, k, nd, nref;
774:   MPI_Comm *comms;
775:   DM       *dms;

777:   PetscFunctionBeginUser;
778:   PetscCall(HierarchyCreate(&nd, &nref, &comms, &dms));

780:   /* destroy user context */
781:   for (d = 0; d < nd; d++) {
782:     DM first = dms[d * nref + 0];

784:     if (first) {
785:       UserContext *ctx = NULL;

787:       PetscCall(DMGetApplicationContext(first, &ctx));
788:       if (ctx) PetscCall(PetscFree(ctx));
789:       PetscCall(DMSetApplicationContext(first, NULL));
790:     }
791:     for (k = 1; k < nref; k++) {
792:       DM dm = dms[d * nref + k];
793:       if (dm) PetscCall(DMSetApplicationContext(dm, NULL));
794:     }
795:   }

797:   /* destroy DMs */
798:   for (k = 0; k < nd * nref; k++) {
799:     if (dms[k]) PetscCall(DMDestroyShellDMDA(&dms[k]));
800:   }
801:   PetscCall(PetscFree(dms));

803:   /* destroy communicators */
804:   for (k = 0; k < nd; k++) {
805:     if (comms[k] != MPI_COMM_NULL) PetscCall(PetscCommDestroy(&comms[k]));
806:   }
807:   PetscCall(PetscFree(comms));
808:   PetscFunctionReturn(PETSC_SUCCESS);
809: }

811: PetscErrorCode test_basic(void)
812: {
813:   DM           dmF, dmdaF = NULL, dmC = NULL;
814:   Mat          A;
815:   Vec          x, b;
816:   KSP          ksp;
817:   PC           pc;
818:   UserContext *user = NULL;

820:   PetscFunctionBeginUser;
821:   PetscCall(UserContextCreate(PETSC_COMM_WORLD, &user));
822:   PetscCall(HierarchyCreate_Basic(&dmF, &dmC, user));
823:   PetscCall(DMShellGetContext(dmF, &dmdaF));

825:   PetscCall(DMCreateMatrix(dmF, &A));
826:   PetscCall(DMCreateGlobalVector(dmF, &x));
827:   PetscCall(DMCreateGlobalVector(dmF, &b));
828:   PetscCall(ComputeRHS_DMDA(dmdaF, b, user));

830:   PetscCall(KSPCreate(PETSC_COMM_WORLD, &ksp));
831:   PetscCall(KSPSetComputeOperators(ksp, ComputeMatrix_ShellDA, user));
832:   /*PetscCall(KSPSetOperators(ksp,A,A));*/
833:   PetscCall(KSPSetDM(ksp, dmF));
834:   PetscCall(KSPSetDMActive(ksp, PETSC_TRUE));
835:   PetscCall(KSPSetFromOptions(ksp));
836:   PetscCall(KSPGetPC(ksp, &pc));
837:   PetscCall(PCTelescopeSetUseCoarseDM(pc, PETSC_TRUE));

839:   PetscCall(KSPSolve(ksp, b, x));

841:   if (dmC) PetscCall(DMDestroyShellDMDA(&dmC));
842:   PetscCall(DMDestroyShellDMDA(&dmF));
843:   PetscCall(KSPDestroy(&ksp));
844:   PetscCall(MatDestroy(&A));
845:   PetscCall(VecDestroy(&b));
846:   PetscCall(VecDestroy(&x));
847:   PetscCall(PetscFree(user));
848:   PetscFunctionReturn(PETSC_SUCCESS);
849: }

851: PetscErrorCode test_mg(void)
852: {
853:   DM           dmF, dmdaF = NULL, *dms = NULL;
854:   Mat          A;
855:   Vec          x, b;
856:   KSP          ksp;
857:   PetscInt     k, d, nd, nref;
858:   MPI_Comm    *comms = NULL;
859:   UserContext *user  = NULL;

861:   PetscFunctionBeginUser;
862:   PetscCall(HierarchyCreate(&nd, &nref, &comms, &dms));
863:   dmF = dms[nd * nref - 1];

865:   PetscCall(DMShellGetContext(dmF, &dmdaF));
866:   PetscCall(DMGetApplicationContext(dmF, &user));

868:   PetscCall(DMCreateMatrix(dmF, &A));
869:   PetscCall(DMCreateGlobalVector(dmF, &x));
870:   PetscCall(DMCreateGlobalVector(dmF, &b));
871:   PetscCall(ComputeRHS_DMDA(dmdaF, b, user));

873:   PetscCall(KSPCreate(PETSC_COMM_WORLD, &ksp));
874:   PetscCall(KSPSetComputeOperators(ksp, ComputeMatrix_ShellDA, user));
875:   /*PetscCall(KSPSetOperators(ksp,A,A));*/
876:   PetscCall(KSPSetDM(ksp, dmF));
877:   PetscCall(KSPSetDMActive(ksp, PETSC_TRUE));
878:   PetscCall(KSPSetFromOptions(ksp));

880:   PetscCall(KSPSolve(ksp, b, x));

882:   for (d = 0; d < nd; d++) {
883:     DM first = dms[d * nref + 0];

885:     if (first) {
886:       UserContext *ctx = NULL;

888:       PetscCall(DMGetApplicationContext(first, &ctx));
889:       if (ctx) PetscCall(PetscFree(ctx));
890:       PetscCall(DMSetApplicationContext(first, NULL));
891:     }
892:     for (k = 1; k < nref; k++) {
893:       DM dm = dms[d * nref + k];
894:       if (dm) PetscCall(DMSetApplicationContext(dm, NULL));
895:     }
896:   }

898:   for (k = 0; k < nd * nref; k++) {
899:     if (dms[k]) PetscCall(DMDestroyShellDMDA(&dms[k]));
900:   }
901:   PetscCall(PetscFree(dms));

903:   PetscCall(KSPDestroy(&ksp));
904:   PetscCall(MatDestroy(&A));
905:   PetscCall(VecDestroy(&b));
906:   PetscCall(VecDestroy(&x));

908:   for (k = 0; k < nd; k++) {
909:     if (comms[k] != MPI_COMM_NULL) PetscCall(PetscCommDestroy(&comms[k]));
910:   }
911:   PetscCall(PetscFree(comms));
912:   PetscFunctionReturn(PETSC_SUCCESS);
913: }

915: int main(int argc, char **argv)
916: {
917:   PetscInt test_id = 0;

919:   PetscFunctionBeginUser;
920:   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
921:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-tid", &test_id, NULL));
922:   switch (test_id) {
923:   case 0:
924:     PetscCall(test_basic());
925:     break;
926:   case 1:
927:     PetscCall(test_hierarchy());
928:     break;
929:   case 2:
930:     PetscCall(test_mg());
931:     break;
932:   default:
933:     SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "-tid must be 0,1,2");
934:   }
935:   PetscCall(PetscFinalize());
936:   return 0;
937: }

939: PetscErrorCode ComputeRHS_DMDA(DM da, Vec b, void *ctx)
940: {
941:   UserContext  *user = (UserContext *)ctx;
942:   PetscInt      i, j, mx, my, xm, ym, xs, ys;
943:   PetscScalar   Hx, Hy;
944:   PetscScalar **array;
945:   PetscBool     isda = PETSC_FALSE;

947:   PetscFunctionBeginUser;
948:   PetscCall(PetscObjectTypeCompare((PetscObject)da, DMDA, &isda));
949:   PetscCheck(isda, PetscObjectComm((PetscObject)da), PETSC_ERR_USER, "DM provided must be a DMDA");
950:   PetscCall(DMDAGetInfo(da, NULL, &mx, &my, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL));
951:   Hx = 1.0 / (PetscReal)(mx - 1);
952:   Hy = 1.0 / (PetscReal)(my - 1);
953:   PetscCall(DMDAGetCorners(da, &xs, &ys, NULL, &xm, &ym, NULL));
954:   PetscCall(DMDAVecGetArray(da, b, &array));
955:   for (j = ys; j < ys + ym; j++) {
956:     for (i = xs; i < xs + xm; i++) array[j][i] = PetscExpScalar(-((PetscReal)i * Hx) * ((PetscReal)i * Hx) / user->nu) * PetscExpScalar(-((PetscReal)j * Hy) * ((PetscReal)j * Hy) / user->nu) * Hx * Hy;
957:   }
958:   PetscCall(DMDAVecRestoreArray(da, b, &array));
959:   PetscCall(VecAssemblyBegin(b));
960:   PetscCall(VecAssemblyEnd(b));

962:   /* force right hand side to be consistent for singular matrix */
963:   /* note this is really a hack, normally the model would provide you with a consistent right handside */
964:   if (user->bcType == NEUMANN) {
965:     MatNullSpace nullspace;

967:     PetscCall(MatNullSpaceCreate(PETSC_COMM_WORLD, PETSC_TRUE, 0, 0, &nullspace));
968:     PetscCall(MatNullSpaceRemove(nullspace, b));
969:     PetscCall(MatNullSpaceDestroy(&nullspace));
970:   }
971:   PetscFunctionReturn(PETSC_SUCCESS);
972: }

974: PetscErrorCode ComputeRho(PetscInt i, PetscInt j, PetscInt mx, PetscInt my, PetscReal centerRho, PetscReal *rho)
975: {
976:   PetscFunctionBeginUser;
977:   if ((i > mx / 3.0) && (i < 2.0 * mx / 3.0) && (j > my / 3.0) && (j < 2.0 * my / 3.0)) {
978:     *rho = centerRho;
979:   } else {
980:     *rho = 1.0;
981:   }
982:   PetscFunctionReturn(PETSC_SUCCESS);
983: }

985: PetscErrorCode ComputeMatrix_DMDA(DM da, Mat J, Mat jac, void *ctx)
986: {
987:   UserContext *user = (UserContext *)ctx;
988:   PetscReal    centerRho;
989:   PetscInt     i, j, mx, my, xm, ym, xs, ys;
990:   PetscScalar  v[5];
991:   PetscReal    Hx, Hy, HydHx, HxdHy, rho;
992:   MatStencil   row, col[5];
993:   PetscBool    isda = PETSC_FALSE;

995:   PetscFunctionBeginUser;
996:   PetscCall(PetscObjectTypeCompare((PetscObject)da, DMDA, &isda));
997:   PetscCheck(isda, PetscObjectComm((PetscObject)da), PETSC_ERR_USER, "DM provided must be a DMDA");
998:   PetscCall(MatZeroEntries(jac));
999:   centerRho = user->rho;
1000:   PetscCall(DMDAGetInfo(da, NULL, &mx, &my, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL));
1001:   Hx    = 1.0 / (PetscReal)(mx - 1);
1002:   Hy    = 1.0 / (PetscReal)(my - 1);
1003:   HxdHy = Hx / Hy;
1004:   HydHx = Hy / Hx;
1005:   PetscCall(DMDAGetCorners(da, &xs, &ys, NULL, &xm, &ym, NULL));
1006:   for (j = ys; j < ys + ym; j++) {
1007:     for (i = xs; i < xs + xm; i++) {
1008:       row.i = i;
1009:       row.j = j;
1010:       PetscCall(ComputeRho(i, j, mx, my, centerRho, &rho));
1011:       if (i == 0 || j == 0 || i == mx - 1 || j == my - 1) {
1012:         if (user->bcType == DIRICHLET) {
1013:           v[0] = 2.0 * rho * (HxdHy + HydHx);
1014:           PetscCall(MatSetValuesStencil(jac, 1, &row, 1, &row, v, INSERT_VALUES));
1015:         } else if (user->bcType == NEUMANN) {
1016:           PetscInt numx = 0, numy = 0, num = 0;
1017:           if (j != 0) {
1018:             v[num]     = -rho * HxdHy;
1019:             col[num].i = i;
1020:             col[num].j = j - 1;
1021:             numy++;
1022:             num++;
1023:           }
1024:           if (i != 0) {
1025:             v[num]     = -rho * HydHx;
1026:             col[num].i = i - 1;
1027:             col[num].j = j;
1028:             numx++;
1029:             num++;
1030:           }
1031:           if (i != mx - 1) {
1032:             v[num]     = -rho * HydHx;
1033:             col[num].i = i + 1;
1034:             col[num].j = j;
1035:             numx++;
1036:             num++;
1037:           }
1038:           if (j != my - 1) {
1039:             v[num]     = -rho * HxdHy;
1040:             col[num].i = i;
1041:             col[num].j = j + 1;
1042:             numy++;
1043:             num++;
1044:           }
1045:           v[num]     = numx * rho * HydHx + numy * rho * HxdHy;
1046:           col[num].i = i;
1047:           col[num].j = j;
1048:           num++;
1049:           PetscCall(MatSetValuesStencil(jac, 1, &row, num, col, v, INSERT_VALUES));
1050:         }
1051:       } else {
1052:         v[0]     = -rho * HxdHy;
1053:         col[0].i = i;
1054:         col[0].j = j - 1;
1055:         v[1]     = -rho * HydHx;
1056:         col[1].i = i - 1;
1057:         col[1].j = j;
1058:         v[2]     = 2.0 * rho * (HxdHy + HydHx);
1059:         col[2].i = i;
1060:         col[2].j = j;
1061:         v[3]     = -rho * HydHx;
1062:         col[3].i = i + 1;
1063:         col[3].j = j;
1064:         v[4]     = -rho * HxdHy;
1065:         col[4].i = i;
1066:         col[4].j = j + 1;
1067:         PetscCall(MatSetValuesStencil(jac, 1, &row, 5, col, v, INSERT_VALUES));
1068:       }
1069:     }
1070:   }
1071:   PetscCall(MatAssemblyBegin(jac, MAT_FINAL_ASSEMBLY));
1072:   PetscCall(MatAssemblyEnd(jac, MAT_FINAL_ASSEMBLY));
1073:   PetscFunctionReturn(PETSC_SUCCESS);
1074: }

1076: PetscErrorCode ComputeMatrix_ShellDA(KSP ksp, Mat J, Mat jac, void *ctx)
1077: {
1078:   DM dm, da;

1080:   PetscFunctionBeginUser;
1081:   PetscCall(KSPGetDM(ksp, &dm));
1082:   PetscCall(DMShellGetContext(dm, &da));
1083:   PetscCall(ComputeMatrix_DMDA(da, J, jac, ctx));
1084:   PetscFunctionReturn(PETSC_SUCCESS);
1085: }

1087: /*TEST

1089:   test:
1090:     suffix: basic_dirichlet
1091:     nsize: 4
1092:     args: -tid 0 -ksp_monitor_short -pc_type telescope -telescope_ksp_max_it 100000 -telescope_pc_type lu -telescope_ksp_type fgmres -telescope_ksp_monitor_short -ksp_type gcr

1094:   test:
1095:     suffix: basic_neumann
1096:     nsize: 4
1097:     requires: !single
1098:     args: -tid 0 -ksp_monitor_short -pc_type telescope -telescope_ksp_max_it 100000 -telescope_pc_type jacobi -telescope_ksp_type fgmres -telescope_ksp_monitor_short -ksp_type gcr -bc_type neumann

1100:   test:
1101:     suffix: mg_2lv_2mg
1102:     nsize: 6
1103:     args: -tid 2 -ksp_monitor_short -ksp_type gcr -pc_type mg -pc_mg_levels 3 -level_nrefs 3 -ndecomps 2 -mg_coarse_pc_type telescope -mg_coarse_pc_telescope_use_coarse_dm -mg_coarse_telescope_pc_type mg -mg_coarse_telescope_pc_mg_levels 3 -level_comm_red_factor 6 -mg_coarse_telescope_mg_coarse_pc_type lu

1105:   test:
1106:     suffix: mg_3lv_2mg
1107:     nsize: 4
1108:     args: -tid 2 -ksp_monitor_short -ksp_type gcr -pc_type mg -pc_mg_levels 3 -level_nrefs 3 -ndecomps 3 -mg_coarse_pc_type telescope -mg_coarse_pc_telescope_use_coarse_dm -mg_coarse_telescope_pc_type mg -mg_coarse_telescope_pc_mg_levels 3 -mg_coarse_telescope_mg_coarse_pc_type telescope -mg_coarse_telescope_mg_coarse_pc_telescope_use_coarse_dm -mg_coarse_telescope_mg_coarse_telescope_pc_type lu -m 5

1110:   test:
1111:     suffix: mg_3lv_2mg_customcommsize
1112:     nsize: 12
1113:     args: -tid 2 -ksp_monitor_short -ksp_type gcr -pc_type mg -pc_mg_levels 3 -level_nrefs 3 -ndecomps 3 -mg_coarse_pc_type telescope -mg_coarse_pc_telescope_use_coarse_dm -m 5 -level_comm_red_factor 2,6 -mg_coarse_telescope_pc_type mg -mg_coarse_telescope_pc_mg_levels 3 -mg_coarse_telescope_mg_coarse_pc_type telescope -mg_coarse_telescope_mg_coarse_pc_telescope_use_coarse_dm -mg_coarse_telescope_mg_coarse_telescope_pc_type lu

1115:  TEST*/