1 #include <petscconvest.h> /*I "petscconvest.h" I*/ 2 #include <petscdmplex.h> 3 #include <petscds.h> 4 5 #include <petsc/private/petscconvestimpl.h> 6 7 static PetscErrorCode zero_private(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar *u, void *ctx) 8 { 9 PetscInt c; 10 for (c = 0; c < Nc; ++c) u[c] = 0.0; 11 return 0; 12 } 13 14 15 /*@ 16 PetscConvEstCreate - Create a PetscConvEst object 17 18 Collective on MPI_Comm 19 20 Input Parameter: 21 . comm - The communicator for the PetscConvEst object 22 23 Output Parameter: 24 . ce - The PetscConvEst object 25 26 Level: beginner 27 28 .keywords: PetscConvEst, convergence, create 29 .seealso: PetscConvEstDestroy(), PetscConvEstGetConvRate() 30 @*/ 31 PetscErrorCode PetscConvEstCreate(MPI_Comm comm, PetscConvEst *ce) 32 { 33 PetscErrorCode ierr; 34 35 PetscFunctionBegin; 36 PetscValidPointer(ce, 2); 37 ierr = PetscSysInitializePackage();CHKERRQ(ierr); 38 ierr = PetscHeaderCreate(*ce, PETSC_OBJECT_CLASSID, "PetscConvEst", "ConvergenceEstimator", "SNES", comm, PetscConvEstDestroy, PetscConvEstView);CHKERRQ(ierr); 39 (*ce)->monitor = PETSC_FALSE; 40 (*ce)->Nr = 4; 41 PetscFunctionReturn(0); 42 } 43 44 /*@ 45 PetscConvEstDestroy - Destroys a PetscConvEst object 46 47 Collective on PetscConvEst 48 49 Input Parameter: 50 . ce - The PetscConvEst object 51 52 Level: beginner 53 54 .keywords: PetscConvEst, convergence, destroy 55 .seealso: PetscConvEstCreate(), PetscConvEstGetConvRate() 56 @*/ 57 PetscErrorCode PetscConvEstDestroy(PetscConvEst *ce) 58 { 59 PetscErrorCode ierr; 60 61 PetscFunctionBegin; 62 if (!*ce) PetscFunctionReturn(0); 63 PetscValidHeaderSpecific((*ce),PETSC_OBJECT_CLASSID,1); 64 if (--((PetscObject)(*ce))->refct > 0) { 65 *ce = NULL; 66 PetscFunctionReturn(0); 67 } 68 ierr = PetscFree3((*ce)->initGuess, (*ce)->exactSol, (*ce)->ctxs);CHKERRQ(ierr); 69 ierr = PetscFree((*ce)->errors);CHKERRQ(ierr); 70 ierr = PetscHeaderDestroy(ce);CHKERRQ(ierr); 71 PetscFunctionReturn(0); 72 } 73 74 /*@ 75 PetscConvEstSetFromOptions - Sets a PetscConvEst object from options 76 77 Collective on PetscConvEst 78 79 Input Parameters: 80 . ce - The PetscConvEst object 81 82 Level: beginner 83 84 .keywords: PetscConvEst, convergence, options 85 .seealso: PetscConvEstCreate(), PetscConvEstGetConvRate() 86 @*/ 87 PetscErrorCode PetscConvEstSetFromOptions(PetscConvEst ce) 88 { 89 PetscErrorCode ierr; 90 91 PetscFunctionBegin; 92 ierr = PetscOptionsBegin(PetscObjectComm((PetscObject) ce), "", "Convergence Estimator Options", "PetscConvEst");CHKERRQ(ierr); 93 ierr = PetscOptionsInt("-convest_num_refine", "The number of refinements for the convergence check", "PetscConvEst", ce->Nr, &ce->Nr, NULL);CHKERRQ(ierr); 94 ierr = PetscOptionsBool("-convest_monitor", "Monitor the error for each convergence check", "PetscConvEst", ce->monitor, &ce->monitor, NULL);CHKERRQ(ierr); 95 ierr = PetscOptionsEnd(); 96 PetscFunctionReturn(0); 97 } 98 99 /*@ 100 PetscConvEstView - Views a PetscConvEst object 101 102 Collective on PetscConvEst 103 104 Input Parameters: 105 + ce - The PetscConvEst object 106 - viewer - The PetscViewer object 107 108 Level: beginner 109 110 .keywords: PetscConvEst, convergence, view 111 .seealso: PetscConvEstCreate(), PetscConvEstGetConvRate() 112 @*/ 113 PetscErrorCode PetscConvEstView(PetscConvEst ce, PetscViewer viewer) 114 { 115 PetscErrorCode ierr; 116 117 PetscFunctionBegin; 118 ierr = PetscObjectPrintClassNamePrefixType((PetscObject) ce, viewer);CHKERRQ(ierr); 119 ierr = PetscViewerASCIIPrintf(viewer, "ConvEst with %D levels\n", ce->Nr+1);CHKERRQ(ierr); 120 PetscFunctionReturn(0); 121 } 122 123 /*@ 124 PetscConvEstGetSolver - Gets the solver used to produce discrete solutions 125 126 Not collective 127 128 Input Parameter: 129 . ce - The PetscConvEst object 130 131 Output Parameter: 132 . snes - The solver 133 134 Level: intermediate 135 136 .keywords: PetscConvEst, convergence 137 .seealso: PetscConvEstSetSolver(), PetscConvEstCreate(), PetscConvEstGetConvRate() 138 @*/ 139 PetscErrorCode PetscConvEstGetSolver(PetscConvEst ce, SNES *snes) 140 { 141 PetscFunctionBegin; 142 PetscValidHeaderSpecific(ce, PETSC_OBJECT_CLASSID, 1); 143 PetscValidPointer(snes, 2); 144 *snes = ce->snes; 145 PetscFunctionReturn(0); 146 } 147 148 /*@ 149 PetscConvEstSetSolver - Sets the solver used to produce discrete solutions 150 151 Not collective 152 153 Input Parameters: 154 + ce - The PetscConvEst object 155 - snes - The solver 156 157 Level: intermediate 158 159 Note: The solver MUST have an attached DM/DS, so that we know the exact solution 160 161 .keywords: PetscConvEst, convergence 162 .seealso: PetscConvEstGetSolver(), PetscConvEstCreate(), PetscConvEstGetConvRate() 163 @*/ 164 PetscErrorCode PetscConvEstSetSolver(PetscConvEst ce, SNES snes) 165 { 166 PetscErrorCode ierr; 167 168 PetscFunctionBegin; 169 PetscValidHeaderSpecific(ce, PETSC_OBJECT_CLASSID, 1); 170 PetscValidHeaderSpecific(snes, SNES_CLASSID, 2); 171 ce->snes = snes; 172 ierr = SNESGetDM(ce->snes, &ce->idm);CHKERRQ(ierr); 173 PetscFunctionReturn(0); 174 } 175 176 /*@ 177 PetscConvEstSetUp - After the solver is specified, we create structures for estimating convergence 178 179 Collective on PetscConvEst 180 181 Input Parameters: 182 . ce - The PetscConvEst object 183 184 Level: beginner 185 186 .keywords: PetscConvEst, convergence, setup 187 .seealso: PetscConvEstCreate(), PetscConvEstGetConvRate() 188 @*/ 189 PetscErrorCode PetscConvEstSetUp(PetscConvEst ce) 190 { 191 PetscDS prob; 192 PetscInt f; 193 PetscErrorCode ierr; 194 195 PetscFunctionBegin; 196 ierr = DMGetDS(ce->idm, &prob);CHKERRQ(ierr); 197 ierr = PetscDSGetNumFields(prob, &ce->Nf);CHKERRQ(ierr); 198 ierr = PetscMalloc1((ce->Nr+1)*ce->Nf, &ce->errors);CHKERRQ(ierr); 199 ierr = PetscMalloc3(ce->Nf, &ce->initGuess, ce->Nf, &ce->exactSol, ce->Nf, &ce->ctxs);CHKERRQ(ierr); 200 for (f = 0; f < ce->Nf; ++f) ce->initGuess[f] = zero_private; 201 for (f = 0; f < ce->Nf; ++f) { 202 ierr = PetscDSGetExactSolution(prob, f, &ce->exactSol[f], &ce->ctxs[f]);CHKERRQ(ierr); 203 if (!ce->exactSol[f]) SETERRQ1(PetscObjectComm((PetscObject) ce), PETSC_ERR_ARG_WRONG, "DS must contain exact solution functions in order to estimate convergence, missing for field %D", f); 204 } 205 PetscFunctionReturn(0); 206 } 207 208 /*@ 209 PetscConvEstGetConvRate - Returns an estimate of the convergence rate for the discretization 210 211 Not collective 212 213 Input Parameter: 214 . ce - The PetscConvEst object 215 216 Output Parameter: 217 . alpha - The convergence rate for each field 218 219 Note: The convergence rate alpha is defined by 220 $ || u_h - u_exact || < C h^alpha 221 where u_h is the discrete solution, and h is a measure of the discretization size. 222 223 We solve a series of problems on refined meshes, calculate an error based upon the exact solution in the DS, 224 and then fit the result to our model above using linear regression. 225 226 Options database keys: 227 . -snes_convergence_estimate : Execute convergence estimation and print out the rate 228 229 Level: intermediate 230 231 .keywords: PetscConvEst, convergence 232 .seealso: PetscConvEstSetSolver(), PetscConvEstCreate(), PetscConvEstGetConvRate() 233 @*/ 234 PetscErrorCode PetscConvEstGetConvRate(PetscConvEst ce, PetscReal alpha[]) 235 { 236 DM *dm; 237 PetscObject disc; 238 MPI_Comm comm; 239 const char *uname, *dmname; 240 void *ctx; 241 Vec u; 242 PetscReal t = 0.0, *x, *y, slope, intercept; 243 PetscInt *dof, dim, Nr = ce->Nr, r, f, oldlevel, oldnlev; 244 PetscLogEvent event; 245 PetscErrorCode ierr; 246 247 PetscFunctionBegin; 248 ierr = PetscObjectGetComm((PetscObject) ce, &comm);CHKERRQ(ierr); 249 ierr = DMGetDimension(ce->idm, &dim);CHKERRQ(ierr); 250 ierr = DMGetApplicationContext(ce->idm, &ctx);CHKERRQ(ierr); 251 ierr = DMPlexSetRefinementUniform(ce->idm, PETSC_TRUE);CHKERRQ(ierr); 252 ierr = DMGetRefineLevel(ce->idm, &oldlevel);CHKERRQ(ierr); 253 ierr = PetscMalloc2((Nr+1), &dm, (Nr+1)*ce->Nf, &dof);CHKERRQ(ierr); 254 dm[0] = ce->idm; 255 for (f = 0; f < ce->Nf; ++f) alpha[f] = 0.0; 256 /* Loop over meshes */ 257 ierr = PetscLogEventRegister("ConvEst Error", PETSC_OBJECT_CLASSID, &event);CHKERRQ(ierr); 258 for (r = 0; r <= Nr; ++r) { 259 PetscLogStage stage; 260 char stageName[PETSC_MAX_PATH_LEN]; 261 262 ierr = PetscSNPrintf(stageName, PETSC_MAX_PATH_LEN-1, "ConvEst Refinement Level %D", r);CHKERRQ(ierr); 263 ierr = PetscLogStageRegister(stageName, &stage);CHKERRQ(ierr); 264 ierr = PetscLogStagePush(stage);CHKERRQ(ierr); 265 if (r > 0) { 266 ierr = DMRefine(dm[r-1], MPI_COMM_NULL, &dm[r]);CHKERRQ(ierr); 267 ierr = DMSetCoarseDM(dm[r], dm[r-1]);CHKERRQ(ierr); 268 ierr = DMCopyDisc(ce->idm, dm[r]);CHKERRQ(ierr); 269 ierr = PetscObjectGetName((PetscObject) dm[r-1], &dmname);CHKERRQ(ierr); 270 ierr = PetscObjectSetName((PetscObject) dm[r], dmname);CHKERRQ(ierr); 271 for (f = 0; f <= ce->Nf; ++f) { 272 PetscErrorCode (*nspconstr)(DM, PetscInt, MatNullSpace *); 273 ierr = DMGetNullSpaceConstructor(dm[r-1], f, &nspconstr);CHKERRQ(ierr); 274 ierr = DMSetNullSpaceConstructor(dm[r], f, nspconstr);CHKERRQ(ierr); 275 } 276 } 277 ierr = DMViewFromOptions(dm[r], NULL, "-conv_dm_view");CHKERRQ(ierr); 278 /* Create solution */ 279 ierr = DMCreateGlobalVector(dm[r], &u);CHKERRQ(ierr); 280 ierr = DMGetField(dm[r], 0, NULL, &disc);CHKERRQ(ierr); 281 ierr = PetscObjectGetName(disc, &uname);CHKERRQ(ierr); 282 ierr = PetscObjectSetName((PetscObject) u, uname);CHKERRQ(ierr); 283 /* Setup solver */ 284 ierr = SNESReset(ce->snes);CHKERRQ(ierr); 285 ierr = SNESSetDM(ce->snes, dm[r]);CHKERRQ(ierr); 286 ierr = DMPlexSetSNESLocalFEM(dm[r], ctx, ctx, ctx);CHKERRQ(ierr); 287 ierr = SNESSetFromOptions(ce->snes);CHKERRQ(ierr); 288 /* Create initial guess */ 289 ierr = DMProjectFunction(dm[r], t, ce->initGuess, ce->ctxs, INSERT_VALUES, u);CHKERRQ(ierr); 290 ierr = SNESSolve(ce->snes, NULL, u);CHKERRQ(ierr); 291 ierr = PetscLogEventBegin(event, ce, 0, 0, 0);CHKERRQ(ierr); 292 ierr = DMComputeL2FieldDiff(dm[r], t, ce->exactSol, ce->ctxs, u, &ce->errors[r*ce->Nf]);CHKERRQ(ierr); 293 ierr = PetscLogEventEnd(event, ce, 0, 0, 0);CHKERRQ(ierr); 294 for (f = 0; f < ce->Nf; ++f) { 295 PetscSection s, fs; 296 PetscInt lsize; 297 298 /* Could use DMGetOutputDM() to add in Dirichlet dofs */ 299 ierr = DMGetSection(dm[r], &s);CHKERRQ(ierr); 300 ierr = PetscSectionGetField(s, f, &fs);CHKERRQ(ierr); 301 ierr = PetscSectionGetConstrainedStorageSize(fs, &lsize);CHKERRQ(ierr); 302 ierr = MPI_Allreduce(&lsize, &dof[r*ce->Nf+f], 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject) ce->snes));CHKERRQ(ierr); 303 ierr = PetscLogEventSetDof(event, f, dof[r*ce->Nf+f]);CHKERRQ(ierr); 304 ierr = PetscLogEventSetError(event, f, ce->errors[r*ce->Nf+f]);CHKERRQ(ierr); 305 } 306 /* Monitor */ 307 if (ce->monitor) { 308 PetscReal *errors = &ce->errors[r*ce->Nf]; 309 310 ierr = PetscPrintf(comm, "L_2 Error: ");CHKERRQ(ierr); 311 if (ce->Nf > 1) {ierr = PetscPrintf(comm, "[");CHKERRQ(ierr);} 312 for (f = 0; f < ce->Nf; ++f) { 313 if (f > 0) {ierr = PetscPrintf(comm, ", ");CHKERRQ(ierr);} 314 if (errors[f] < 1.0e-11) {ierr = PetscPrintf(comm, "< 1e-11");CHKERRQ(ierr);} 315 else {ierr = PetscPrintf(comm, "%g", (double)errors[f]);CHKERRQ(ierr);} 316 } 317 if (ce->Nf > 1) {ierr = PetscPrintf(comm, "]");CHKERRQ(ierr);} 318 ierr = PetscPrintf(comm, "\n");CHKERRQ(ierr); 319 } 320 if (!r) { 321 /* PCReset() does not wipe out the level structure */ 322 KSP ksp; 323 PC pc; 324 325 ierr = SNESGetKSP(ce->snes, &ksp);CHKERRQ(ierr); 326 ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr); 327 ierr = PCMGGetLevels(pc, &oldnlev);CHKERRQ(ierr); 328 } 329 /* Cleanup */ 330 ierr = VecDestroy(&u);CHKERRQ(ierr); 331 ierr = PetscLogStagePop();CHKERRQ(ierr); 332 } 333 for (r = 1; r <= Nr; ++r) { 334 ierr = DMDestroy(&dm[r]);CHKERRQ(ierr); 335 } 336 /* Fit convergence rate */ 337 ierr = PetscMalloc2(Nr+1, &x, Nr+1, &y);CHKERRQ(ierr); 338 for (f = 0; f < ce->Nf; ++f) { 339 for (r = 0; r <= Nr; ++r) { 340 x[r] = PetscLog10Real(dof[r*ce->Nf+f]); 341 y[r] = PetscLog10Real(ce->errors[r*ce->Nf+f]); 342 } 343 ierr = PetscLinearRegression(Nr+1, x, y, &slope, &intercept);CHKERRQ(ierr); 344 /* Since h^{-dim} = N, lg err = s lg N + b = -s dim lg h + b */ 345 alpha[f] = -slope * dim; 346 } 347 ierr = PetscFree2(x, y);CHKERRQ(ierr); 348 ierr = PetscFree2(dm, dof);CHKERRQ(ierr); 349 /* Restore solver */ 350 ierr = SNESReset(ce->snes);CHKERRQ(ierr); 351 { 352 /* PCReset() does not wipe out the level structure */ 353 KSP ksp; 354 PC pc; 355 356 ierr = SNESGetKSP(ce->snes, &ksp);CHKERRQ(ierr); 357 ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr); 358 ierr = PCMGSetLevels(pc, oldnlev, NULL);CHKERRQ(ierr); 359 ierr = DMSetRefineLevel(ce->idm, oldlevel);CHKERRQ(ierr); /* The damn DMCoarsen() calls in PCMG can reset this */ 360 } 361 ierr = SNESSetDM(ce->snes, ce->idm);CHKERRQ(ierr); 362 ierr = DMPlexSetSNESLocalFEM(ce->idm, ctx, ctx, ctx);CHKERRQ(ierr); 363 ierr = SNESSetFromOptions(ce->snes);CHKERRQ(ierr); 364 PetscFunctionReturn(0); 365 } 366 367 /*@ 368 PetscConvEstRateView - Displays the convergence rate to a viewer 369 370 Collective on SNES 371 372 Parameter: 373 + snes - iterative context obtained from SNESCreate() 374 . alpha - the convergence rate for each field 375 - viewer - the viewer to display the reason 376 377 Options Database Keys: 378 . -snes_convergence_estimate - print the convergence rate 379 380 Level: developer 381 382 .seealso: PetscConvEstGetRate() 383 @*/ 384 PetscErrorCode PetscConvEstRateView(PetscConvEst ce, const PetscReal alpha[], PetscViewer viewer) 385 { 386 PetscBool isAscii; 387 PetscErrorCode ierr; 388 389 PetscFunctionBegin; 390 ierr = PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERASCII, &isAscii);CHKERRQ(ierr); 391 if (isAscii) { 392 DM dm; 393 PetscInt Nf, f; 394 395 ierr = SNESGetDM(ce->snes, &dm);CHKERRQ(ierr); 396 ierr = DMGetNumFields(dm, &Nf);CHKERRQ(ierr); 397 ierr = PetscViewerASCIIAddTab(viewer, ((PetscObject) ce)->tablevel);CHKERRQ(ierr); 398 ierr = PetscViewerASCIIPrintf(viewer, "L_2 convergence rate: ");CHKERRQ(ierr); 399 if (Nf > 1) {ierr = PetscViewerASCIIPrintf(viewer, "[");CHKERRQ(ierr);} 400 for (f = 0; f < Nf; ++f) { 401 if (f > 0) {ierr = PetscViewerASCIIPrintf(viewer, ", ");CHKERRQ(ierr);} 402 ierr = PetscViewerASCIIPrintf(viewer, "%#.2g", (double) alpha[f]);CHKERRQ(ierr); 403 } 404 if (Nf > 1) {ierr = PetscViewerASCIIPrintf(viewer, "]");CHKERRQ(ierr);} 405 ierr = PetscViewerASCIIPrintf(viewer, "\n");CHKERRQ(ierr); 406 ierr = PetscViewerASCIISubtractTab(viewer, ((PetscObject) ce)->tablevel);CHKERRQ(ierr); 407 } 408 PetscFunctionReturn(0); 409 } 410