1 /* Defines the basic SNES object */ 2 #include <../src/snes/impls/fas/fasimpls.h> /*I "petscsnesfas.h" I*/ 3 4 const char *SNESFASTypes[] = {"MULTIPLICATIVE","ADDITIVE","SNESFASType","SNES_FAS",0}; 5 6 extern PetscErrorCode SNESDestroy_FAS(SNES snes); 7 extern PetscErrorCode SNESSetUp_FAS(SNES snes); 8 extern PetscErrorCode SNESSetFromOptions_FAS(SNES snes); 9 extern PetscErrorCode SNESView_FAS(SNES snes, PetscViewer viewer); 10 extern PetscErrorCode SNESSolve_FAS(SNES snes); 11 extern PetscErrorCode SNESReset_FAS(SNES snes); 12 extern PetscErrorCode SNESFASGalerkinDefaultFunction(SNES, Vec, Vec, void *); 13 extern PetscErrorCode SNESFASCycleCreateSmoother_Private(SNES, SNES *); 14 15 /*MC 16 17 SNESFAS - Full Approximation Scheme nonlinear multigrid solver. 18 19 The nonlinear problem is solved by correction using coarse versions 20 of the nonlinear problem. This problem is perturbed so that a projected 21 solution of the fine problem elicits no correction from the coarse problem. 22 23 Options Database: 24 + -snes_fas_levels - The number of levels 25 . -snes_fas_cycles<1> - The number of cycles -- 1 for V, 2 for W 26 . -snes_fas_type<additive, multiplicative> - Additive or multiplicative cycle 27 . -snes_fas_galerkin<PETSC_FALSE> - Form coarse problems by projection back upon the fine problem 28 . -snes_fas_smoothup<1> - The number of iterations of the post-smoother 29 . -snes_fas_smoothdown<1> - The number of iterations of the pre-smoother 30 . -snes_fas_monitor - Monitor progress of all of the levels 31 . -fas_levels_snes_ - SNES options for all smoothers 32 . -fas_levels_cycle_snes_ - SNES options for all cycles 33 . -fas_levels_i_snes_ - SNES options for the smoothers on level i 34 . -fas_levels_i_cycle_snes_ - SNES options for the cycle on level i 35 - -fas_coarse_snes_ - SNES options for the coarsest smoother 36 37 Notes: 38 The organization of the FAS solver is slightly different from the organization of PCMG 39 As each level has smoother SNES instances(down and potentially up) and a cycle SNES instance. 40 The cycle SNES instance may be used for monitoring convergence on a particular level. 41 42 Level: beginner 43 44 .seealso: PCMG, SNESCreate(), SNES, SNESSetType(), SNESType (for list of available types) 45 M*/ 46 47 #undef __FUNCT__ 48 #define __FUNCT__ "SNESCreate_FAS" 49 PETSC_EXTERN_C PetscErrorCode SNESCreate_FAS(SNES snes) 50 { 51 SNES_FAS * fas; 52 PetscErrorCode ierr; 53 54 PetscFunctionBegin; 55 snes->ops->destroy = SNESDestroy_FAS; 56 snes->ops->setup = SNESSetUp_FAS; 57 snes->ops->setfromoptions = SNESSetFromOptions_FAS; 58 snes->ops->view = SNESView_FAS; 59 snes->ops->solve = SNESSolve_FAS; 60 snes->ops->reset = SNESReset_FAS; 61 62 snes->usesksp = PETSC_FALSE; 63 snes->usespc = PETSC_FALSE; 64 65 if (!snes->tolerancesset) { 66 snes->max_funcs = 30000; 67 snes->max_its = 10000; 68 } 69 70 ierr = PetscNewLog(snes, SNES_FAS, &fas);CHKERRQ(ierr); 71 snes->data = (void*) fas; 72 fas->level = 0; 73 fas->levels = 1; 74 fas->n_cycles = 1; 75 fas->max_up_it = 1; 76 fas->max_down_it = 1; 77 fas->smoothu = PETSC_NULL; 78 fas->smoothd = PETSC_NULL; 79 fas->next = PETSC_NULL; 80 fas->previous = PETSC_NULL; 81 fas->fine = snes; 82 fas->interpolate = PETSC_NULL; 83 fas->restrct = PETSC_NULL; 84 fas->inject = PETSC_NULL; 85 fas->monitor = PETSC_NULL; 86 fas->usedmfornumberoflevels = PETSC_FALSE; 87 fas->fastype = SNES_FAS_MULTIPLICATIVE; 88 PetscFunctionReturn(0); 89 } 90 91 #undef __FUNCT__ 92 #define __FUNCT__ "SNESReset_FAS" 93 PetscErrorCode SNESReset_FAS(SNES snes) 94 { 95 PetscErrorCode ierr = 0; 96 SNES_FAS * fas = (SNES_FAS *)snes->data; 97 98 PetscFunctionBegin; 99 ierr = SNESDestroy(&fas->smoothu);CHKERRQ(ierr); 100 ierr = SNESDestroy(&fas->smoothd);CHKERRQ(ierr); 101 ierr = MatDestroy(&fas->inject);CHKERRQ(ierr); 102 ierr = MatDestroy(&fas->interpolate);CHKERRQ(ierr); 103 ierr = MatDestroy(&fas->restrct);CHKERRQ(ierr); 104 ierr = VecDestroy(&fas->rscale);CHKERRQ(ierr); 105 if (fas->next) ierr = SNESReset(fas->next);CHKERRQ(ierr); 106 107 PetscFunctionReturn(0); 108 } 109 110 #undef __FUNCT__ 111 #define __FUNCT__ "SNESDestroy_FAS" 112 PetscErrorCode SNESDestroy_FAS(SNES snes) 113 { 114 SNES_FAS * fas = (SNES_FAS *)snes->data; 115 PetscErrorCode ierr = 0; 116 117 PetscFunctionBegin; 118 /* recursively resets and then destroys */ 119 ierr = SNESReset(snes);CHKERRQ(ierr); 120 if (fas->next) ierr = SNESDestroy(&fas->next);CHKERRQ(ierr); 121 ierr = PetscFree(fas);CHKERRQ(ierr); 122 123 PetscFunctionReturn(0); 124 } 125 126 #undef __FUNCT__ 127 #define __FUNCT__ "SNESSetUp_FAS" 128 PetscErrorCode SNESSetUp_FAS(SNES snes) 129 { 130 SNES_FAS *fas = (SNES_FAS *) snes->data; 131 PetscErrorCode ierr; 132 VecScatter injscatter; 133 PetscInt dm_levels; 134 Vec vec_sol, vec_func, vec_sol_update, vec_rhs; /* preserve these if they're set through the reset */ 135 SNES next; 136 PetscBool isFine; 137 SNESLineSearch linesearch; 138 SNESLineSearch slinesearch; 139 void *lsprectx,*lspostctx; 140 SNESLineSearchPreCheckFunc lsprefunc; 141 SNESLineSearchPostCheckFunc lspostfunc; 142 PetscFunctionBegin; 143 144 ierr = SNESFASCycleIsFine(snes, &isFine);CHKERRQ(ierr); 145 if (fas->usedmfornumberoflevels && isFine) { 146 ierr = DMGetRefineLevel(snes->dm,&dm_levels);CHKERRQ(ierr); 147 dm_levels++; 148 if (dm_levels > fas->levels) { 149 /* we don't want the solution and func vectors to be destroyed in the SNESReset when it's called in SNESFASSetLevels_FAS*/ 150 vec_sol = snes->vec_sol; 151 vec_func = snes->vec_func; 152 vec_sol_update = snes->vec_sol_update; 153 vec_rhs = snes->vec_rhs; 154 snes->vec_sol = PETSC_NULL; 155 snes->vec_func = PETSC_NULL; 156 snes->vec_sol_update = PETSC_NULL; 157 snes->vec_rhs = PETSC_NULL; 158 159 /* reset the number of levels */ 160 ierr = SNESFASSetLevels(snes,dm_levels,PETSC_NULL);CHKERRQ(ierr); 161 ierr = SNESSetFromOptions(snes);CHKERRQ(ierr); 162 163 snes->vec_sol = vec_sol; 164 snes->vec_func = vec_func; 165 snes->vec_rhs = vec_rhs; 166 snes->vec_sol_update = vec_sol_update; 167 } 168 } 169 ierr = SNESFASCycleGetCorrection(snes, &next);CHKERRQ(ierr); 170 if (!isFine) snes->gridsequence = 0; /* no grid sequencing inside the multigrid hierarchy! */ 171 172 if (fas->fastype == SNES_FAS_MULTIPLICATIVE) { 173 ierr = SNESDefaultGetWork(snes, 2);CHKERRQ(ierr); /* work vectors used for intergrid transfers */ 174 } else { 175 ierr = SNESDefaultGetWork(snes, 2);CHKERRQ(ierr); /* work vectors used for intergrid transfers */ 176 } 177 178 /* set up the smoothers if they haven't already been set up */ 179 if (!fas->smoothd) { 180 ierr = SNESFASCycleCreateSmoother_Private(snes, &fas->smoothd);CHKERRQ(ierr); 181 } 182 if (!fas->smoothu && fas->level != fas->levels - 1) { 183 ierr = SNESFASCycleCreateSmoother_Private(snes, &fas->smoothu);CHKERRQ(ierr); 184 } 185 186 if (snes->dm) { 187 /* set the smoother DMs properly */ 188 if (fas->smoothu) ierr = SNESSetDM(fas->smoothu, snes->dm);CHKERRQ(ierr); 189 ierr = SNESSetDM(fas->smoothd, snes->dm);CHKERRQ(ierr); 190 /* construct EVERYTHING from the DM -- including the progressive set of smoothers */ 191 if (next) { 192 /* for now -- assume the DM and the evaluation functions have been set externally */ 193 if (!next->dm) { 194 ierr = DMCoarsen(snes->dm, ((PetscObject)next)->comm, &next->dm);CHKERRQ(ierr); 195 ierr = SNESSetDM(next, next->dm);CHKERRQ(ierr); 196 } 197 /* set the interpolation and restriction from the DM */ 198 if (!fas->interpolate) { 199 ierr = DMCreateInterpolation(next->dm, snes->dm, &fas->interpolate, &fas->rscale);CHKERRQ(ierr); 200 if (!fas->restrct) { 201 ierr = PetscObjectReference((PetscObject)fas->interpolate);CHKERRQ(ierr); 202 fas->restrct = fas->interpolate; 203 } 204 } 205 /* set the injection from the DM */ 206 if (!fas->inject) { 207 ierr = DMCreateInjection(next->dm, snes->dm, &injscatter);CHKERRQ(ierr); 208 ierr = MatCreateScatter(((PetscObject)snes)->comm, injscatter, &fas->inject);CHKERRQ(ierr); 209 ierr = VecScatterDestroy(&injscatter);CHKERRQ(ierr); 210 } 211 } 212 } 213 /*pass the smoother, function, and jacobian up to the next level if it's not user set already */ 214 if (fas->galerkin) { 215 if (next) 216 ierr = SNESSetFunction(next, PETSC_NULL, SNESFASGalerkinDefaultFunction, next);CHKERRQ(ierr); 217 if (fas->smoothd && fas->level != fas->levels - 1) ierr = SNESSetFunction(fas->smoothd, PETSC_NULL, SNESFASGalerkinDefaultFunction, snes);CHKERRQ(ierr); 218 if (fas->smoothu && fas->level != fas->levels - 1) ierr = SNESSetFunction(fas->smoothu, PETSC_NULL, SNESFASGalerkinDefaultFunction, snes);CHKERRQ(ierr); 219 } 220 221 /* sets the down (pre) smoother's default norm and sets it from options */ 222 if(fas->smoothd){ 223 if (fas->level == 0) { 224 ierr = SNESSetNormType(fas->smoothd, SNES_NORM_NONE);CHKERRQ(ierr); 225 } else { 226 ierr = SNESSetNormType(fas->smoothd, SNES_NORM_FINAL_ONLY);CHKERRQ(ierr); 227 } 228 ierr = SNESSetFromOptions(fas->smoothd);CHKERRQ(ierr); 229 ierr = SNESGetSNESLineSearch(snes,&linesearch);CHKERRQ(ierr); 230 ierr = SNESGetSNESLineSearch(fas->smoothd,&slinesearch);CHKERRQ(ierr); 231 ierr = SNESLineSearchGetPreCheck(linesearch,&lsprefunc,&lsprectx);CHKERRQ(ierr); 232 ierr = SNESLineSearchGetPostCheck(linesearch,&lspostfunc,&lspostctx);CHKERRQ(ierr); 233 ierr = SNESLineSearchSetPreCheck(slinesearch,lsprefunc,lsprectx);CHKERRQ(ierr); 234 ierr = SNESLineSearchSetPostCheck(slinesearch,lspostfunc,lspostctx);CHKERRQ(ierr); 235 ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)slinesearch);CHKERRQ(ierr); 236 } 237 238 /* sets the up (post) smoother's default norm and sets it from options */ 239 if(fas->smoothu){ 240 if (fas->level != fas->levels - 1) { 241 ierr = SNESSetNormType(fas->smoothu, SNES_NORM_NONE);CHKERRQ(ierr); 242 } else { 243 ierr = SNESSetNormType(fas->smoothu, SNES_NORM_FINAL_ONLY);CHKERRQ(ierr); 244 } 245 ierr = SNESSetFromOptions(fas->smoothu);CHKERRQ(ierr); 246 ierr = SNESGetSNESLineSearch(snes,&linesearch);CHKERRQ(ierr); 247 ierr = SNESGetSNESLineSearch(fas->smoothu,&slinesearch);CHKERRQ(ierr); 248 ierr = SNESLineSearchGetPreCheck(linesearch,&lsprefunc,&lsprectx);CHKERRQ(ierr); 249 ierr = SNESLineSearchGetPostCheck(linesearch,&lspostfunc,&lspostctx);CHKERRQ(ierr); 250 ierr = SNESLineSearchSetPreCheck(slinesearch,lsprefunc,lsprectx);CHKERRQ(ierr); 251 ierr = SNESLineSearchSetPostCheck(slinesearch,lspostfunc,lspostctx);CHKERRQ(ierr); 252 ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)slinesearch);CHKERRQ(ierr); 253 } 254 255 if (next) { 256 /* gotta set up the solution vector for this to work */ 257 if (!next->vec_sol) {ierr = SNESFASCreateCoarseVec(snes,&next->vec_sol);CHKERRQ(ierr);} 258 if (!next->vec_rhs) {ierr = SNESFASCreateCoarseVec(snes,&next->vec_rhs);CHKERRQ(ierr);} 259 ierr = SNESGetSNESLineSearch(snes,&linesearch);CHKERRQ(ierr); 260 ierr = SNESGetSNESLineSearch(fas->next,&slinesearch);CHKERRQ(ierr); 261 ierr = SNESLineSearchGetPreCheck(linesearch,&lsprefunc,&lsprectx);CHKERRQ(ierr); 262 ierr = SNESLineSearchGetPostCheck(linesearch,&lspostfunc,&lspostctx);CHKERRQ(ierr); 263 ierr = SNESLineSearchSetPreCheck(slinesearch,lsprefunc,lsprectx);CHKERRQ(ierr); 264 ierr = SNESLineSearchSetPostCheck(slinesearch,lspostfunc,lspostctx);CHKERRQ(ierr); 265 ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)slinesearch);CHKERRQ(ierr); 266 ierr = SNESSetUp(next);CHKERRQ(ierr); 267 } 268 /* setup FAS work vectors */ 269 if (fas->galerkin) { 270 ierr = VecDuplicate(snes->vec_sol, &fas->Xg);CHKERRQ(ierr); 271 ierr = VecDuplicate(snes->vec_sol, &fas->Fg);CHKERRQ(ierr); 272 } 273 PetscFunctionReturn(0); 274 } 275 276 #undef __FUNCT__ 277 #define __FUNCT__ "SNESSetFromOptions_FAS" 278 PetscErrorCode SNESSetFromOptions_FAS(SNES snes) 279 { 280 SNES_FAS *fas = (SNES_FAS *) snes->data; 281 PetscInt levels = 1; 282 PetscBool flg = PETSC_FALSE, upflg = PETSC_FALSE, downflg = PETSC_FALSE, monflg = PETSC_FALSE, galerkinflg = PETSC_FALSE; 283 PetscErrorCode ierr; 284 char monfilename[PETSC_MAX_PATH_LEN]; 285 SNESFASType fastype; 286 const char *optionsprefix; 287 SNESLineSearch linesearch; 288 PetscInt m, n_up, n_down; 289 SNES next; 290 PetscBool isFine; 291 292 PetscFunctionBegin; 293 ierr = SNESFASCycleIsFine(snes, &isFine);CHKERRQ(ierr); 294 ierr = PetscOptionsHead("SNESFAS Options-----------------------------------");CHKERRQ(ierr); 295 296 /* number of levels -- only process most options on the finest level */ 297 if (isFine) { 298 ierr = PetscOptionsInt("-snes_fas_levels", "Number of Levels", "SNESFASSetLevels", levels, &levels, &flg);CHKERRQ(ierr); 299 if (!flg && snes->dm) { 300 ierr = DMGetRefineLevel(snes->dm,&levels);CHKERRQ(ierr); 301 levels++; 302 fas->usedmfornumberoflevels = PETSC_TRUE; 303 } 304 ierr = SNESFASSetLevels(snes, levels, PETSC_NULL);CHKERRQ(ierr); 305 fastype = fas->fastype; 306 ierr = PetscOptionsEnum("-snes_fas_type","FAS correction type","SNESFASSetType",SNESFASTypes,(PetscEnum)fastype,(PetscEnum*)&fastype,&flg);CHKERRQ(ierr); 307 if (flg) { 308 ierr = SNESFASSetType(snes, fastype);CHKERRQ(ierr); 309 } 310 311 ierr = SNESGetOptionsPrefix(snes, &optionsprefix);CHKERRQ(ierr); 312 ierr = PetscOptionsInt("-snes_fas_cycles","Number of cycles","SNESFASSetCycles",fas->n_cycles,&m,&flg);CHKERRQ(ierr); 313 if (flg) { 314 ierr = SNESFASSetCycles(snes, m);CHKERRQ(ierr); 315 } 316 317 ierr = PetscOptionsBool("-snes_fas_galerkin", "Form coarse problems with Galerkin","SNESFASSetGalerkin",fas->galerkin,&galerkinflg,&flg);CHKERRQ(ierr); 318 if (flg) { 319 ierr = SNESFASSetGalerkin(snes, galerkinflg);CHKERRQ(ierr); 320 } 321 322 ierr = PetscOptionsInt("-snes_fas_smoothup","Number of post-smoothing steps","SNESFASSetNumberSmoothUp",fas->max_up_it,&n_up,&upflg);CHKERRQ(ierr); 323 324 ierr = PetscOptionsInt("-snes_fas_smoothdown","Number of pre-smoothing steps","SNESFASSetNumberSmoothDown",fas->max_down_it,&n_down,&downflg);CHKERRQ(ierr); 325 326 ierr = PetscOptionsString("-snes_fas_monitor","Monitor FAS progress","SNESFASSetMonitor","stdout",monfilename,PETSC_MAX_PATH_LEN,&monflg);CHKERRQ(ierr); 327 if (monflg) ierr = SNESFASSetMonitor(snes, PETSC_TRUE);CHKERRQ(ierr); 328 } 329 330 ierr = PetscOptionsTail();CHKERRQ(ierr); 331 /* setup from the determined types if there is no pointwise procedure or smoother defined */ 332 if (upflg) { 333 ierr = SNESFASSetNumberSmoothUp(snes,n_up);CHKERRQ(ierr); 334 } 335 if (downflg) { 336 ierr = SNESFASSetNumberSmoothDown(snes,n_down);CHKERRQ(ierr); 337 } 338 339 /* set up the default line search for coarse grid corrections */ 340 if (fas->fastype == SNES_FAS_ADDITIVE) { 341 if (!snes->linesearch) { 342 ierr = SNESGetSNESLineSearch(snes, &linesearch);CHKERRQ(ierr); 343 ierr = SNESLineSearchSetType(linesearch, SNESLINESEARCHL2);CHKERRQ(ierr); 344 } 345 } 346 347 ierr = SNESFASCycleGetCorrection(snes, &next);CHKERRQ(ierr); 348 /* recursive option setting for the smoothers */ 349 if (next) {ierr = SNESSetFromOptions(next);CHKERRQ(ierr);} 350 PetscFunctionReturn(0); 351 } 352 353 #undef __FUNCT__ 354 #define __FUNCT__ "SNESView_FAS" 355 PetscErrorCode SNESView_FAS(SNES snes, PetscViewer viewer) 356 { 357 SNES_FAS *fas = (SNES_FAS *) snes->data; 358 PetscBool isFine, iascii; 359 PetscInt i; 360 PetscErrorCode ierr; 361 SNES smoothu, smoothd, levelsnes; 362 363 PetscFunctionBegin; 364 ierr = SNESFASCycleIsFine(snes, &isFine);CHKERRQ(ierr); 365 if (isFine) { 366 ierr = PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERASCII, &iascii);CHKERRQ(ierr); 367 if (iascii) { 368 ierr = PetscViewerASCIIPrintf(viewer, "FAS: type is %s, levels=%D, cycles=%D\n", SNESFASTypes[fas->fastype], fas->levels, fas->n_cycles);CHKERRQ(ierr); 369 if (fas->galerkin) { 370 ierr = PetscViewerASCIIPrintf(viewer," Using Galerkin computed coarse grid function evaluation\n");CHKERRQ(ierr); 371 } else { 372 ierr = PetscViewerASCIIPrintf(viewer," Not using Galerkin computed coarse grid function evaluation\n");CHKERRQ(ierr); 373 } 374 for (i=0; i<fas->levels; i++) { 375 ierr = SNESFASGetCycleSNES(snes, i, &levelsnes);CHKERRQ(ierr); 376 ierr = SNESFASCycleGetSmootherUp(levelsnes, &smoothu);CHKERRQ(ierr); 377 ierr = SNESFASCycleGetSmootherDown(levelsnes, &smoothd);CHKERRQ(ierr); 378 if (!i) { 379 ierr = PetscViewerASCIIPrintf(viewer,"Coarse grid solver -- level %D -------------------------------\n",i);CHKERRQ(ierr); 380 } else { 381 ierr = PetscViewerASCIIPrintf(viewer,"Down solver (pre-smoother) on level %D -------------------------------\n",i);CHKERRQ(ierr); 382 } 383 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 384 ierr = SNESView(smoothd,viewer);CHKERRQ(ierr); 385 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 386 if (i && (smoothd == smoothu)) { 387 ierr = PetscViewerASCIIPrintf(viewer,"Up solver (post-smoother) same as down solver (pre-smoother)\n");CHKERRQ(ierr); 388 } else if (i) { 389 ierr = PetscViewerASCIIPrintf(viewer,"Up solver (post-smoother) on level %D -------------------------------\n",i);CHKERRQ(ierr); 390 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 391 ierr = SNESView(smoothu,viewer);CHKERRQ(ierr); 392 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 393 } 394 } 395 } else { 396 SETERRQ1(((PetscObject)snes)->comm,PETSC_ERR_SUP,"Viewer type %s not supported for SNESFAS",((PetscObject)viewer)->type_name); 397 } 398 } 399 PetscFunctionReturn(0); 400 } 401 402 #undef __FUNCT__ 403 #define __FUNCT__ "SNESFASDownSmooth_Private" 404 /* 405 Defines the action of the downsmoother 406 */ 407 PetscErrorCode SNESFASDownSmooth_Private(SNES snes, Vec B, Vec X, Vec F, PetscReal *fnorm) 408 { 409 PetscErrorCode ierr = 0; 410 SNESConvergedReason reason; 411 Vec FPC; 412 SNES smoothd; 413 PetscFunctionBegin; 414 ierr = SNESFASCycleGetSmootherDown(snes, &smoothd);CHKERRQ(ierr); 415 ierr = SNESSetInitialFunction(smoothd, F);CHKERRQ(ierr); 416 ierr = SNESSetInitialFunctionNorm(smoothd, *fnorm);CHKERRQ(ierr); 417 ierr = SNESSolve(smoothd, B, X);CHKERRQ(ierr); 418 /* check convergence reason for the smoother */ 419 ierr = SNESGetConvergedReason(smoothd,&reason);CHKERRQ(ierr); 420 if (reason < 0 && !(reason == SNES_DIVERGED_MAX_IT || reason == SNES_DIVERGED_LOCAL_MIN)) { 421 snes->reason = SNES_DIVERGED_INNER; 422 PetscFunctionReturn(0); 423 } 424 ierr = SNESGetFunction(smoothd, &FPC, PETSC_NULL, PETSC_NULL);CHKERRQ(ierr); 425 ierr = VecCopy(FPC, F);CHKERRQ(ierr); 426 ierr = SNESGetFunctionNorm(smoothd, fnorm);CHKERRQ(ierr); 427 PetscFunctionReturn(0); 428 } 429 430 431 #undef __FUNCT__ 432 #define __FUNCT__ "SNESFASUpSmooth_Private" 433 /* 434 Defines the action of the upsmoother 435 */ 436 PetscErrorCode SNESFASUpSmooth_Private (SNES snes, Vec B, Vec X, Vec F, PetscReal *fnorm) { 437 PetscErrorCode ierr = 0; 438 SNESConvergedReason reason; 439 Vec FPC; 440 SNES smoothu; 441 PetscFunctionBegin; 442 443 ierr = SNESFASCycleGetSmootherUp(snes, &smoothu);CHKERRQ(ierr); 444 ierr = SNESSolve(smoothu, B, X);CHKERRQ(ierr); 445 /* check convergence reason for the smoother */ 446 ierr = SNESGetConvergedReason(smoothu,&reason);CHKERRQ(ierr); 447 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 448 snes->reason = SNES_DIVERGED_INNER; 449 PetscFunctionReturn(0); 450 } 451 ierr = SNESGetFunction(smoothu, &FPC, PETSC_NULL, PETSC_NULL);CHKERRQ(ierr); 452 ierr = VecCopy(FPC, F);CHKERRQ(ierr); 453 ierr = SNESGetFunctionNorm(smoothu, fnorm);CHKERRQ(ierr); 454 PetscFunctionReturn(0); 455 } 456 457 #undef __FUNCT__ 458 #define __FUNCT__ "SNESFASCreateCoarseVec" 459 /*@ 460 SNESFASCreateCoarseVec - create Vec corresponding to a state vector on one level coarser than current level 461 462 Collective 463 464 Input Arguments: 465 . snes - SNESFAS 466 467 Output Arguments: 468 . Xcoarse - vector on level one coarser than snes 469 470 Level: developer 471 472 .seealso: SNESFASSetRestriction(), SNESFASRestrict() 473 @*/ 474 PetscErrorCode SNESFASCreateCoarseVec(SNES snes,Vec *Xcoarse) 475 { 476 PetscErrorCode ierr; 477 SNES_FAS *fas = (SNES_FAS*)snes->data; 478 479 PetscFunctionBegin; 480 if (fas->rscale) {ierr = VecDuplicate(fas->rscale,Xcoarse);CHKERRQ(ierr);} 481 else if (fas->inject) {ierr = MatGetVecs(fas->inject,Xcoarse,PETSC_NULL);CHKERRQ(ierr);} 482 else SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Must set restriction or injection");CHKERRQ(ierr); 483 PetscFunctionReturn(0); 484 } 485 486 #undef __FUNCT__ 487 #define __FUNCT__ "SNESFASRestrict" 488 /*@ 489 SNESFASRestrict - restrict a Vec to the next coarser level 490 491 Collective 492 493 Input Arguments: 494 + fine - SNES from which to restrict 495 - Xfine - vector to restrict 496 497 Output Arguments: 498 . Xcoarse - result of restriction 499 500 Level: developer 501 502 .seealso: SNESFASSetRestriction(), SNESFASSetInjection() 503 @*/ 504 PetscErrorCode SNESFASRestrict(SNES fine,Vec Xfine,Vec Xcoarse) 505 { 506 PetscErrorCode ierr; 507 SNES_FAS *fas = (SNES_FAS*)fine->data; 508 509 PetscFunctionBegin; 510 PetscValidHeaderSpecific(fine,SNES_CLASSID,1); 511 PetscValidHeaderSpecific(Xfine,VEC_CLASSID,2); 512 PetscValidHeaderSpecific(Xcoarse,VEC_CLASSID,3); 513 if (fas->inject) { 514 ierr = MatRestrict(fas->inject,Xfine,Xcoarse);CHKERRQ(ierr); 515 } else { 516 ierr = MatRestrict(fas->restrct,Xfine,Xcoarse);CHKERRQ(ierr); 517 ierr = VecPointwiseMult(Xcoarse,fas->rscale,Xcoarse);CHKERRQ(ierr); 518 } 519 PetscFunctionReturn(0); 520 } 521 522 #undef __FUNCT__ 523 #define __FUNCT__ "SNESFASCoarseCorrection" 524 /* 525 526 Performs the FAS coarse correction as: 527 528 fine problem: F(x) = 0 529 coarse problem: F^c(x) = b^c 530 531 b^c = F^c(I^c_fx^f - I^c_fF(x)) 532 533 */ 534 PetscErrorCode SNESFASCoarseCorrection(SNES snes, Vec X, Vec F, Vec X_new) { 535 PetscErrorCode ierr; 536 Vec X_c, Xo_c, F_c, B_c; 537 SNESConvergedReason reason; 538 SNES next; 539 Mat restrct, interpolate; 540 PetscFunctionBegin; 541 ierr = SNESFASCycleGetCorrection(snes, &next);CHKERRQ(ierr); 542 if (next) { 543 ierr = SNESFASCycleGetRestriction(snes, &restrct);CHKERRQ(ierr); 544 ierr = SNESFASCycleGetInterpolation(snes, &interpolate);CHKERRQ(ierr); 545 546 X_c = next->vec_sol; 547 Xo_c = next->work[0]; 548 F_c = next->vec_func; 549 B_c = next->vec_rhs; 550 551 ierr = SNESFASRestrict(snes,X,Xo_c);CHKERRQ(ierr); 552 /* restrict the defect */ 553 ierr = MatRestrict(restrct, F, B_c);CHKERRQ(ierr); 554 /* solve the coarse problem corresponding to F^c(x^c) = b^c = F^c(Rx) - R(F(x) - b) */ 555 ierr = SNESComputeFunction(next, Xo_c, F_c);CHKERRQ(ierr); 556 ierr = VecCopy(B_c, X_c);CHKERRQ(ierr); 557 ierr = VecCopy(F_c, B_c);CHKERRQ(ierr); 558 ierr = VecCopy(X_c, F_c);CHKERRQ(ierr); 559 /* set initial guess of the coarse problem to the projected fine solution */ 560 ierr = VecCopy(Xo_c, X_c);CHKERRQ(ierr); 561 562 /* recurse to the next level */ 563 ierr = SNESSetInitialFunction(next, F_c);CHKERRQ(ierr); 564 ierr = SNESSolve(next, B_c, X_c);CHKERRQ(ierr); 565 ierr = SNESGetConvergedReason(next,&reason);CHKERRQ(ierr); 566 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 567 snes->reason = SNES_DIVERGED_INNER; 568 PetscFunctionReturn(0); 569 } 570 /* correct as x <- x + I(x^c - Rx)*/ 571 ierr = VecAXPY(X_c, -1.0, Xo_c);CHKERRQ(ierr); 572 ierr = MatInterpolateAdd(interpolate, X_c, X, X_new);CHKERRQ(ierr); 573 } 574 PetscFunctionReturn(0); 575 } 576 577 #undef __FUNCT__ 578 #define __FUNCT__ "SNESFASCycle_Additive" 579 /* 580 581 The additive cycle looks like: 582 583 xhat = x 584 xhat = dS(x, b) 585 x = coarsecorrection(xhat, b_d) 586 x = x + nu*(xhat - x); 587 (optional) x = uS(x, b) 588 589 With the coarse RHS (defect correction) as below. 590 591 */ 592 PetscErrorCode SNESFASCycle_Additive(SNES snes, Vec X) { 593 Vec F, B, Xhat; 594 Vec X_c, Xo_c, F_c, B_c; 595 PetscErrorCode ierr; 596 SNESConvergedReason reason; 597 PetscReal xnorm, fnorm, ynorm; 598 PetscBool lssuccess; 599 SNES next; 600 Mat restrct, interpolate; 601 PetscFunctionBegin; 602 ierr = SNESFASCycleGetCorrection(snes, &next);CHKERRQ(ierr); 603 F = snes->vec_func; 604 B = snes->vec_rhs; 605 Xhat = snes->work[1]; 606 ierr = VecCopy(X, Xhat);CHKERRQ(ierr); 607 /* recurse first */ 608 if (next) { 609 ierr = SNESFASCycleGetRestriction(snes, &restrct);CHKERRQ(ierr); 610 ierr = SNESFASCycleGetInterpolation(snes, &interpolate);CHKERRQ(ierr); 611 ierr = SNESComputeFunction(snes, Xhat, F);CHKERRQ(ierr); 612 ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); 613 X_c = next->vec_sol; 614 Xo_c = next->work[0]; 615 F_c = next->vec_func; 616 B_c = next->vec_rhs; 617 618 ierr = SNESFASRestrict(snes,Xhat,Xo_c);CHKERRQ(ierr); 619 /* restrict the defect */ 620 ierr = MatRestrict(restrct, F, B_c);CHKERRQ(ierr); 621 622 /* solve the coarse problem corresponding to F^c(x^c) = b^c = Rb + F^c(Rx) - RF(x) */ 623 ierr = SNESComputeFunction(next, Xo_c, F_c);CHKERRQ(ierr); 624 ierr = VecCopy(B_c, X_c);CHKERRQ(ierr); 625 ierr = VecCopy(F_c, B_c);CHKERRQ(ierr); 626 ierr = VecCopy(X_c, F_c);CHKERRQ(ierr); 627 /* set initial guess of the coarse problem to the projected fine solution */ 628 ierr = VecCopy(Xo_c, X_c);CHKERRQ(ierr); 629 630 /* recurse */ 631 ierr = SNESSetInitialFunction(next, F_c);CHKERRQ(ierr); 632 ierr = SNESSolve(next, B_c, X_c);CHKERRQ(ierr); 633 634 /* smooth on this level */ 635 ierr = SNESFASDownSmooth_Private(snes, B, X, F, &fnorm);CHKERRQ(ierr); 636 637 ierr = SNESGetConvergedReason(next,&reason);CHKERRQ(ierr); 638 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 639 snes->reason = SNES_DIVERGED_INNER; 640 PetscFunctionReturn(0); 641 } 642 643 /* correct as x <- x + I(x^c - Rx)*/ 644 ierr = VecAYPX(X_c, -1.0, Xo_c);CHKERRQ(ierr); 645 ierr = MatInterpolate(interpolate, X_c, Xhat);CHKERRQ(ierr); 646 647 /* additive correction of the coarse direction*/ 648 ierr = SNESLineSearchApply(snes->linesearch, X, F, &fnorm, Xhat);CHKERRQ(ierr); 649 ierr = SNESLineSearchGetSuccess(snes->linesearch, &lssuccess);CHKERRQ(ierr); 650 if (!lssuccess) { 651 if (++snes->numFailures >= snes->maxFailures) { 652 snes->reason = SNES_DIVERGED_LINE_SEARCH; 653 PetscFunctionReturn(0); 654 } 655 } 656 ierr = SNESLineSearchGetNorms(snes->linesearch, &xnorm, &snes->norm, &ynorm);CHKERRQ(ierr); 657 } else { 658 ierr = SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm);CHKERRQ(ierr); 659 } 660 PetscFunctionReturn(0); 661 } 662 663 #undef __FUNCT__ 664 #define __FUNCT__ "SNESFASCycle_Multiplicative" 665 /* 666 667 Defines the FAS cycle as: 668 669 fine problem: F(x) = 0 670 coarse problem: F^c(x) = b^c 671 672 b^c = F^c(I^c_fx^f - I^c_fF(x)) 673 674 correction: 675 676 x = x + I(x^c - Rx) 677 678 */ 679 PetscErrorCode SNESFASCycle_Multiplicative(SNES snes, Vec X) { 680 681 PetscErrorCode ierr; 682 Vec F,B; 683 SNES_FAS *fas = (SNES_FAS *)snes->data; 684 685 PetscFunctionBegin; 686 F = snes->vec_func; 687 B = snes->vec_rhs; 688 /* pre-smooth -- just update using the pre-smoother */ 689 ierr = SNESFASDownSmooth_Private(snes, B, X, F, &snes->norm);CHKERRQ(ierr); 690 if (fas->level != 0) { 691 ierr = SNESFASCoarseCorrection(snes, X, F, X);CHKERRQ(ierr); 692 ierr = SNESFASUpSmooth_Private(snes, B, X, F, &snes->norm);CHKERRQ(ierr); 693 } 694 PetscFunctionReturn(0); 695 } 696 697 #undef __FUNCT__ 698 #define __FUNCT__ "SNESSolve_FAS" 699 700 PetscErrorCode SNESSolve_FAS(SNES snes) 701 { 702 PetscErrorCode ierr; 703 PetscInt i, maxits; 704 Vec X, F; 705 PetscReal fnorm; 706 SNES_FAS *fas = (SNES_FAS *)snes->data,*ffas; 707 DM dm; 708 PetscBool isFine; 709 710 PetscFunctionBegin; 711 maxits = snes->max_its; /* maximum number of iterations */ 712 snes->reason = SNES_CONVERGED_ITERATING; 713 X = snes->vec_sol; 714 F = snes->vec_func; 715 716 ierr = SNESFASCycleIsFine(snes, &isFine);CHKERRQ(ierr); 717 /*norm setup */ 718 ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr); 719 snes->iter = 0; 720 snes->norm = 0.; 721 ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr); 722 if (!snes->vec_func_init_set) { 723 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 724 if (snes->domainerror) { 725 snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN; 726 PetscFunctionReturn(0); 727 } 728 } else { 729 snes->vec_func_init_set = PETSC_FALSE; 730 } 731 732 if (!snes->norm_init_set) { 733 ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); /* fnorm <- ||F|| */ 734 if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"Infinite or not-a-number generated in norm"); 735 ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr); 736 } else { 737 fnorm = snes->norm_init; 738 snes->norm_init_set = PETSC_FALSE; 739 } 740 741 snes->norm = fnorm; 742 ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr); 743 SNESLogConvHistory(snes,fnorm,0); 744 ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr); 745 746 /* set parameter for default relative tolerance convergence test */ 747 snes->ttol = fnorm*snes->rtol; 748 /* test convergence */ 749 ierr = (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr); 750 if (snes->reason) PetscFunctionReturn(0); 751 752 753 if (isFine) { 754 /* propagate scale-dependent data up the hierarchy */ 755 ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr); 756 for (ffas=fas; ffas->next; ffas=(SNES_FAS*)ffas->next->data) { 757 DM dmcoarse; 758 ierr = SNESGetDM(ffas->next,&dmcoarse);CHKERRQ(ierr); 759 ierr = DMRestrict(dm,ffas->restrct,ffas->rscale,ffas->inject,dmcoarse);CHKERRQ(ierr); 760 dm = dmcoarse; 761 } 762 } 763 764 for (i = 0; i < maxits; i++) { 765 /* Call general purpose update function */ 766 767 if (snes->ops->update) { 768 ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr); 769 } 770 if (fas->fastype == SNES_FAS_MULTIPLICATIVE) { 771 ierr = SNESFASCycle_Multiplicative(snes, X);CHKERRQ(ierr); 772 } else { 773 ierr = SNESFASCycle_Additive(snes, X);CHKERRQ(ierr); 774 } 775 776 /* check for FAS cycle divergence */ 777 if (snes->reason != SNES_CONVERGED_ITERATING) { 778 PetscFunctionReturn(0); 779 } 780 781 /* Monitor convergence */ 782 ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr); 783 snes->iter = i+1; 784 ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr); 785 SNESLogConvHistory(snes,snes->norm,0); 786 ierr = SNESMonitor(snes,snes->iter,snes->norm);CHKERRQ(ierr); 787 /* Test for convergence */ 788 if (isFine) { 789 ierr = (*snes->ops->converged)(snes,snes->iter,0.0,0.0,snes->norm,&snes->reason,snes->cnvP);CHKERRQ(ierr); 790 if (snes->reason) break; 791 } 792 } 793 if (i == maxits) { 794 ierr = PetscInfo1(snes, "Maximum number of iterations has been reached: %D\n", maxits);CHKERRQ(ierr); 795 if (!snes->reason) snes->reason = SNES_DIVERGED_MAX_IT; 796 } 797 PetscFunctionReturn(0); 798 } 799