1 2 #include <petsc/private/matimpl.h> 3 #include <petsc/private/pcimpl.h> 4 #include <petsc/private/dmimpl.h> 5 #include <petscksp.h> /*I "petscksp.h" I*/ 6 #include <petscdm.h> 7 #include <petscdmda.h> 8 #include <petscdmshell.h> 9 10 #include "../src/ksp/pc/impls/telescope/telescope.h" 11 12 static PetscBool cited = PETSC_FALSE; 13 static const char citation[] = 14 "@inproceedings{MaySananRuppKnepleySmith2016,\n" 15 " title = {Extreme-Scale Multigrid Components within PETSc},\n" 16 " author = {Dave A. May and Patrick Sanan and Karl Rupp and Matthew G. Knepley and Barry F. Smith},\n" 17 " booktitle = {Proceedings of the Platform for Advanced Scientific Computing Conference},\n" 18 " series = {PASC '16},\n" 19 " isbn = {978-1-4503-4126-4},\n" 20 " location = {Lausanne, Switzerland},\n" 21 " pages = {5:1--5:12},\n" 22 " articleno = {5},\n" 23 " numpages = {12},\n" 24 " url = {https://doi.acm.org/10.1145/2929908.2929913},\n" 25 " doi = {10.1145/2929908.2929913},\n" 26 " acmid = {2929913},\n" 27 " publisher = {ACM},\n" 28 " address = {New York, NY, USA},\n" 29 " keywords = {GPU, HPC, agglomeration, coarse-level solver, multigrid, parallel computing, preconditioning},\n" 30 " year = {2016}\n" 31 "}\n"; 32 33 typedef struct { 34 DM dm_fine,dm_coarse; /* these DM's should be topologically identical but use different communicators */ 35 Mat permutation; 36 Vec xp; 37 PetscErrorCode (*fp_dm_field_scatter)(DM,Vec,ScatterMode,DM,Vec); 38 PetscErrorCode (*fp_dm_state_scatter)(DM,ScatterMode,DM); 39 void *dmksp_context_determined; 40 void *dmksp_context_user; 41 } PC_Telescope_CoarseDMCtx; 42 43 PetscErrorCode PCTelescopeSetUp_scatters_CoarseDM(PC pc,PC_Telescope sred,PC_Telescope_CoarseDMCtx *ctx) 44 { 45 PetscErrorCode ierr; 46 Vec xred,yred,xtmp,x,xp; 47 VecScatter scatter; 48 IS isin; 49 Mat B; 50 PetscInt m,bs,st,ed; 51 MPI_Comm comm; 52 53 PetscFunctionBegin; 54 ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr); 55 ierr = PCGetOperators(pc,NULL,&B);CHKERRQ(ierr); 56 ierr = MatCreateVecs(B,&x,NULL);CHKERRQ(ierr); 57 ierr = MatGetBlockSize(B,&bs);CHKERRQ(ierr); 58 ierr = VecDuplicate(x,&xp);CHKERRQ(ierr); 59 m = 0; 60 xred = NULL; 61 yred = NULL; 62 if (PCTelescope_isActiveRank(sred)) { 63 ierr = DMCreateGlobalVector(ctx->dm_coarse,&xred);CHKERRQ(ierr); 64 ierr = VecDuplicate(xred,&yred);CHKERRQ(ierr); 65 ierr = VecGetOwnershipRange(xred,&st,&ed);CHKERRQ(ierr); 66 ierr = ISCreateStride(comm,ed-st,st,1,&isin);CHKERRQ(ierr); 67 ierr = VecGetLocalSize(xred,&m);CHKERRQ(ierr); 68 } else { 69 ierr = VecGetOwnershipRange(x,&st,&ed);CHKERRQ(ierr); 70 ierr = ISCreateStride(comm,0,st,1,&isin);CHKERRQ(ierr); 71 } 72 ierr = ISSetBlockSize(isin,bs);CHKERRQ(ierr); 73 ierr = VecCreate(comm,&xtmp);CHKERRQ(ierr); 74 ierr = VecSetSizes(xtmp,m,PETSC_DECIDE);CHKERRQ(ierr); 75 ierr = VecSetBlockSize(xtmp,bs);CHKERRQ(ierr); 76 ierr = VecSetType(xtmp,((PetscObject)x)->type_name);CHKERRQ(ierr); 77 ierr = VecScatterCreate(x,isin,xtmp,NULL,&scatter);CHKERRQ(ierr); 78 sred->xred = xred; 79 sred->yred = yred; 80 sred->isin = isin; 81 sred->scatter = scatter; 82 sred->xtmp = xtmp; 83 ctx->xp = xp; 84 ierr = VecDestroy(&x);CHKERRQ(ierr); 85 PetscFunctionReturn(0); 86 } 87 88 PetscErrorCode PCTelescopeSetUp_CoarseDM(PC pc,PC_Telescope sred) 89 { 90 PC_Telescope_CoarseDMCtx *ctx; 91 DM dm,dm_coarse = NULL; 92 MPI_Comm comm; 93 PetscBool has_perm,has_kspcomputeoperators,using_kspcomputeoperators; 94 PetscErrorCode ierr; 95 96 PetscFunctionBegin; 97 ierr = PetscInfo(pc,"PCTelescope: setup (CoarseDM)\n");CHKERRQ(ierr); 98 ierr = PetscNew(&ctx);CHKERRQ(ierr); 99 sred->dm_ctx = (void*)ctx; 100 101 ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr); 102 ierr = PCGetDM(pc,&dm);CHKERRQ(ierr); 103 ierr = DMGetCoarseDM(dm,&dm_coarse);CHKERRQ(ierr); 104 ctx->dm_fine = dm; 105 ctx->dm_coarse = dm_coarse; 106 107 /* attach coarse dm to ksp on sub communicator */ 108 if (PCTelescope_isActiveRank(sred)) { 109 ierr = KSPSetDM(sred->ksp,ctx->dm_coarse);CHKERRQ(ierr); 110 if (sred->ignore_kspcomputeoperators) { 111 ierr = KSPSetDMActive(sred->ksp,PETSC_FALSE);CHKERRQ(ierr); 112 } 113 } 114 115 /* check if there is a method to provide a permutation */ 116 has_perm = PETSC_FALSE; 117 has_kspcomputeoperators = PETSC_FALSE; 118 using_kspcomputeoperators = PETSC_FALSE; 119 120 /* if no permutation is provided, we must rely on KSPSetComputeOperators */ 121 { 122 PetscErrorCode (*dmfine_kspfunc)(KSP,Mat,Mat,void*) = NULL; 123 void *dmfine_kspctx = NULL,*dmcoarse_kspctx = NULL; 124 void *dmfine_appctx = NULL,*dmcoarse_appctx = NULL; 125 void *dmfine_shellctx = NULL,*dmcoarse_shellctx = NULL; 126 127 ierr = DMKSPGetComputeOperators(dm,&dmfine_kspfunc,&dmfine_kspctx);CHKERRQ(ierr); 128 if (dmfine_kspfunc) { has_kspcomputeoperators = PETSC_TRUE; } 129 130 ierr = DMGetApplicationContext(ctx->dm_fine,&dmfine_appctx);CHKERRQ(ierr); 131 ierr = DMShellGetContext(ctx->dm_fine,&dmfine_shellctx);CHKERRQ(ierr); 132 133 /* need to define dmcoarse_kspctx */ 134 if (dmfine_kspfunc && !sred->ignore_kspcomputeoperators) { 135 136 ierr = PetscInfo(pc,"PCTelescope: KSPSetComputeOperators fetched from parent DM\n");CHKERRQ(ierr); 137 if (PCTelescope_isActiveRank(sred)) { 138 ierr = DMGetApplicationContext(ctx->dm_coarse,&dmcoarse_appctx);CHKERRQ(ierr); 139 ierr = DMShellGetContext(ctx->dm_coarse,&dmcoarse_shellctx);CHKERRQ(ierr); 140 } 141 142 /* Assume that if the fine operator didn't require any context, neither will the coarse */ 143 if (!dmfine_kspctx) { 144 dmcoarse_kspctx = NULL; 145 ierr = PetscInfo(pc,"PCTelescope: KSPSetComputeOperators using NULL context\n");CHKERRQ(ierr); 146 } else { 147 148 ierr = PetscInfo(pc,"PCTelescope: KSPSetComputeOperators detected non-NULL context from parent DM \n");CHKERRQ(ierr); 149 if (PCTelescope_isActiveRank(sred)) { 150 151 if (dmfine_kspctx == dmfine_appctx) { 152 dmcoarse_kspctx = dmcoarse_appctx; 153 ierr = PetscInfo(pc,"PCTelescope: KSPSetComputeOperators using context from DM->ApplicationContext\n");CHKERRQ(ierr); 154 if (!dmcoarse_kspctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Non NULL dmfine->kspctx == dmfine->appctx. NULL dmcoarse->appctx found. Likely this is an error"); 155 } else if (dmfine_kspctx == dmfine_shellctx) { 156 dmcoarse_kspctx = dmcoarse_shellctx; 157 ierr = PetscInfo(pc,"PCTelescope: KSPSetComputeOperators using context from DMShell->Context\n");CHKERRQ(ierr); 158 if (!dmcoarse_kspctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Non NULL dmfine->kspctx == dmfine.shell->ctx. NULL dmcoarse.shell->ctx found. Likely this is an error"); 159 } 160 ctx->dmksp_context_determined = dmcoarse_kspctx; 161 162 /* look for user provided method to fetch the context */ 163 { 164 PetscErrorCode (*fp_get_coarsedm_context)(DM,void**) = NULL; 165 void *dmcoarse_context_user = NULL; 166 char dmcoarse_method[PETSC_MAX_PATH_LEN]; 167 168 ierr = PetscSNPrintf(dmcoarse_method,sizeof(dmcoarse_method),"PCTelescopeGetCoarseDMKSPContext");CHKERRQ(ierr); 169 ierr = PetscObjectQueryFunction((PetscObject)ctx->dm_coarse,dmcoarse_method,&fp_get_coarsedm_context);CHKERRQ(ierr); 170 if (fp_get_coarsedm_context) { 171 ierr = PetscInfo(pc,"PCTelescope: Found composed method PCTelescopeGetCoarseDMKSPContext from coarse DM\n");CHKERRQ(ierr); 172 ierr = fp_get_coarsedm_context(ctx->dm_coarse,&dmcoarse_context_user);CHKERRQ(ierr); 173 ctx->dmksp_context_user = dmcoarse_context_user; 174 dmcoarse_kspctx = dmcoarse_context_user; 175 } else { 176 ierr = PetscInfo(pc,"PCTelescope: Failed to find composed method PCTelescopeGetCoarseDMKSPContext from coarse DM\n");CHKERRQ(ierr); 177 } 178 } 179 180 if (!dmcoarse_kspctx) { 181 ierr = PetscInfo(pc,"PCTelescope: KSPSetComputeOperators failed to determine the context to use on sub-communicator\n");CHKERRQ(ierr); 182 SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot determine which context with use for KSPSetComputeOperators() on sub-communicator"); 183 } 184 } 185 } 186 } 187 188 if (dmfine_kspfunc && !sred->ignore_kspcomputeoperators) { 189 using_kspcomputeoperators = PETSC_TRUE; 190 191 if (PCTelescope_isActiveRank(sred)) { 192 /* sub ksp inherits dmksp_func and context provided by user */ 193 ierr = KSPSetComputeOperators(sred->ksp,dmfine_kspfunc,dmcoarse_kspctx);CHKERRQ(ierr); 194 /*ierr = PetscObjectCopyFortranFunctionPointers((PetscObject)dm,(PetscObject)ctx->dmrepart);CHKERRQ(ierr);*/ 195 ierr = KSPSetDMActive(sred->ksp,PETSC_TRUE);CHKERRQ(ierr); 196 } 197 } 198 } 199 200 if (!has_perm && has_kspcomputeoperators && !using_kspcomputeoperators) SETERRQ(comm,PETSC_ERR_SUP,"No method to permute an operator was found on the parent DM. A method for KSPSetComputeOperators() was provided but it was requested to be ignored. Telescope setup cannot proceed"); 201 if (!has_perm && !has_kspcomputeoperators) SETERRQ(comm,PETSC_ERR_SUP,"No method to permute an operator was found on the parent DM. No method for KSPSetComputeOperators() was provided. Telescope setup cannot proceed"); 202 203 { 204 char dmfine_method[PETSC_MAX_PATH_LEN]; 205 206 ierr = PetscSNPrintf(dmfine_method,sizeof(dmfine_method),"PCTelescopeFieldScatter");CHKERRQ(ierr); 207 ierr = PetscObjectQueryFunction((PetscObject)ctx->dm_fine,dmfine_method,&ctx->fp_dm_field_scatter);CHKERRQ(ierr); 208 209 ierr = PetscSNPrintf(dmfine_method,sizeof(dmfine_method),"PCTelescopeStateScatter");CHKERRQ(ierr); 210 ierr = PetscObjectQueryFunction((PetscObject)ctx->dm_fine,dmfine_method,&ctx->fp_dm_state_scatter);CHKERRQ(ierr); 211 } 212 213 if (ctx->fp_dm_state_scatter) { 214 ierr = PetscInfo(pc,"PCTelescope: Found composed method PCTelescopeStateScatter from parent DM\n");CHKERRQ(ierr); 215 } else { 216 ierr = PetscInfo(pc,"PCTelescope: Failed to find composed method PCTelescopeStateScatter from parent DM\n");CHKERRQ(ierr); 217 } 218 219 if (ctx->fp_dm_field_scatter) { 220 ierr = PetscInfo(pc,"PCTelescope: Found composed method PCTelescopeFieldScatter from parent DM\n");CHKERRQ(ierr); 221 } else { 222 ierr = PetscInfo(pc,"PCTelescope: Failed to find composed method PCTelescopeFieldScatter from parent DM\n");CHKERRQ(ierr); 223 SETERRQ(comm,PETSC_ERR_SUP,"No method to scatter fields between the parent DM and coarse DM was found. Must call PetscObjectComposeFunction() with the parent DM. Telescope setup cannot proceed"); 224 } 225 226 /*ierr = PCTelescopeSetUp_permutation_CoarseDM(pc,sred,ctx);CHKERRQ(ierr);*/ 227 ierr = PCTelescopeSetUp_scatters_CoarseDM(pc,sred,ctx);CHKERRQ(ierr); 228 PetscFunctionReturn(0); 229 } 230 231 PetscErrorCode PCApply_Telescope_CoarseDM(PC pc,Vec x,Vec y) 232 { 233 PC_Telescope sred = (PC_Telescope)pc->data; 234 PetscErrorCode ierr; 235 Vec xred,yred; 236 PC_Telescope_CoarseDMCtx *ctx; 237 238 PetscFunctionBegin; 239 ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx; 240 xred = sred->xred; 241 yred = sred->yred; 242 243 ierr = PetscCitationsRegister(citation,&cited);CHKERRQ(ierr); 244 245 if (ctx->fp_dm_state_scatter) { 246 ierr = ctx->fp_dm_state_scatter(ctx->dm_fine,SCATTER_FORWARD,ctx->dm_coarse);CHKERRQ(ierr); 247 } 248 249 ierr = ctx->fp_dm_field_scatter(ctx->dm_fine,x,SCATTER_FORWARD,ctx->dm_coarse,xred);CHKERRQ(ierr); 250 251 /* solve */ 252 if (PCTelescope_isActiveRank(sred)) { 253 ierr = KSPSolve(sred->ksp,xred,yred);CHKERRQ(ierr); 254 } 255 256 ierr = ctx->fp_dm_field_scatter(ctx->dm_fine,y,SCATTER_REVERSE,ctx->dm_coarse,yred);CHKERRQ(ierr); 257 PetscFunctionReturn(0); 258 } 259 260 PetscErrorCode PCTelescopeSubNullSpaceCreate_CoarseDM(PC pc,PC_Telescope sred,MatNullSpace nullspace,MatNullSpace *sub_nullspace) 261 { 262 PetscErrorCode ierr; 263 PetscBool has_const; 264 PetscInt k,n = 0; 265 const Vec *vecs; 266 Vec *sub_vecs = NULL; 267 MPI_Comm subcomm; 268 PC_Telescope_CoarseDMCtx *ctx; 269 270 PetscFunctionBegin; 271 ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx; 272 subcomm = sred->subcomm; 273 ierr = MatNullSpaceGetVecs(nullspace,&has_const,&n,&vecs);CHKERRQ(ierr); 274 275 if (PCTelescope_isActiveRank(sred)) { 276 /* create new vectors */ 277 if (n) { 278 ierr = VecDuplicateVecs(sred->xred,n,&sub_vecs);CHKERRQ(ierr); 279 } 280 } 281 282 /* copy entries */ 283 for (k=0; k<n; k++) { 284 ierr = ctx->fp_dm_field_scatter(ctx->dm_fine,vecs[k],SCATTER_FORWARD,ctx->dm_coarse,sub_vecs[k]);CHKERRQ(ierr); 285 } 286 287 if (PCTelescope_isActiveRank(sred)) { 288 /* create new (near) nullspace for redundant object */ 289 ierr = MatNullSpaceCreate(subcomm,has_const,n,sub_vecs,sub_nullspace);CHKERRQ(ierr); 290 ierr = VecDestroyVecs(n,&sub_vecs);CHKERRQ(ierr); 291 } 292 PetscFunctionReturn(0); 293 } 294 295 PetscErrorCode PCTelescopeMatNullSpaceCreate_CoarseDM(PC pc,PC_Telescope sred,Mat sub_mat) 296 { 297 PetscErrorCode ierr; 298 Mat B; 299 PC_Telescope_CoarseDMCtx *ctx; 300 301 PetscFunctionBegin; 302 ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx; 303 ierr = PCGetOperators(pc,NULL,&B);CHKERRQ(ierr); 304 { 305 MatNullSpace nullspace,sub_nullspace; 306 ierr = MatGetNullSpace(B,&nullspace);CHKERRQ(ierr); 307 if (nullspace) { 308 ierr = PetscInfo(pc,"PCTelescope: generating nullspace (CoarseDM)\n");CHKERRQ(ierr); 309 ierr = PCTelescopeSubNullSpaceCreate_CoarseDM(pc,sred,nullspace,&sub_nullspace);CHKERRQ(ierr); 310 311 /* attach any user nullspace removal methods and contexts */ 312 if (PCTelescope_isActiveRank(sred)) { 313 void *context = NULL; 314 if (nullspace->remove && !nullspace->rmctx) { 315 ierr = MatNullSpaceSetFunction(sub_nullspace,nullspace->remove,context);CHKERRQ(ierr); 316 } else if (nullspace->remove && nullspace->rmctx) { 317 char dmcoarse_method[PETSC_MAX_PATH_LEN]; 318 PetscErrorCode (*fp_get_coarsedm_context)(DM,void**) = NULL; 319 320 ierr = PetscSNPrintf(dmcoarse_method,sizeof(dmcoarse_method),"PCTelescopeGetCoarseDMNullSpaceUserContext");CHKERRQ(ierr); 321 ierr = PetscObjectQueryFunction((PetscObject)ctx->dm_coarse,dmcoarse_method,&fp_get_coarsedm_context);CHKERRQ(ierr); 322 if (!context) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Propagation of user null-space removal method with non-NULL context requires the coarse DM be composed with a function named \"%s\"",dmcoarse_method); 323 ierr = MatNullSpaceSetFunction(sub_nullspace,nullspace->remove,context);CHKERRQ(ierr); 324 } 325 } 326 327 if (PCTelescope_isActiveRank(sred)) { 328 ierr = MatSetNullSpace(sub_mat,sub_nullspace);CHKERRQ(ierr); 329 ierr = MatNullSpaceDestroy(&sub_nullspace);CHKERRQ(ierr); 330 } 331 } 332 } 333 { 334 MatNullSpace nearnullspace,sub_nearnullspace; 335 ierr = MatGetNearNullSpace(B,&nearnullspace);CHKERRQ(ierr); 336 if (nearnullspace) { 337 ierr = PetscInfo(pc,"PCTelescope: generating near nullspace (CoarseDM)\n");CHKERRQ(ierr); 338 ierr = PCTelescopeSubNullSpaceCreate_CoarseDM(pc,sred,nearnullspace,&sub_nearnullspace);CHKERRQ(ierr); 339 340 /* attach any user nullspace removal methods and contexts */ 341 if (PCTelescope_isActiveRank(sred)) { 342 void *context = NULL; 343 if (nearnullspace->remove && !nearnullspace->rmctx) { 344 ierr = MatNullSpaceSetFunction(sub_nearnullspace,nearnullspace->remove,context);CHKERRQ(ierr); 345 } else if (nearnullspace->remove && nearnullspace->rmctx) { 346 char dmcoarse_method[PETSC_MAX_PATH_LEN]; 347 PetscErrorCode (*fp_get_coarsedm_context)(DM,void**) = NULL; 348 349 ierr = PetscSNPrintf(dmcoarse_method,sizeof(dmcoarse_method),"PCTelescopeGetCoarseDMNearNullSpaceUserContext");CHKERRQ(ierr); 350 ierr = PetscObjectQueryFunction((PetscObject)ctx->dm_coarse,dmcoarse_method,&fp_get_coarsedm_context);CHKERRQ(ierr); 351 if (!context) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Propagation of user near null-space removal method with non-NULL context requires the coarse DM be composed with a function named \"%s\"",dmcoarse_method); 352 ierr = MatNullSpaceSetFunction(sub_nearnullspace,nearnullspace->remove,context);CHKERRQ(ierr); 353 } 354 } 355 356 if (PCTelescope_isActiveRank(sred)) { 357 ierr = MatSetNearNullSpace(sub_mat,sub_nearnullspace);CHKERRQ(ierr); 358 ierr = MatNullSpaceDestroy(&sub_nearnullspace);CHKERRQ(ierr); 359 } 360 } 361 } 362 PetscFunctionReturn(0); 363 } 364 365 PetscErrorCode PCReset_Telescope_CoarseDM(PC pc) 366 { 367 PetscErrorCode ierr; 368 PC_Telescope sred = (PC_Telescope)pc->data; 369 PC_Telescope_CoarseDMCtx *ctx; 370 371 PetscFunctionBegin; 372 ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx; 373 ctx->dm_fine = NULL; /* since I did not increment the ref counter we set these to NULL */ 374 ctx->dm_coarse = NULL; /* since I did not increment the ref counter we set these to NULL */ 375 ctx->permutation = NULL; /* this will be fetched from the dm so no need to call destroy */ 376 ierr = VecDestroy(&ctx->xp);CHKERRQ(ierr); 377 ctx->fp_dm_field_scatter = NULL; 378 ctx->fp_dm_state_scatter = NULL; 379 ctx->dmksp_context_determined = NULL; 380 ctx->dmksp_context_user = NULL; 381 PetscFunctionReturn(0); 382 } 383 384 PetscErrorCode PCApplyRichardson_Telescope_CoarseDM(PC pc,Vec x,Vec y,Vec w,PetscReal rtol,PetscReal abstol,PetscReal dtol,PetscInt its,PetscBool zeroguess,PetscInt *outits,PCRichardsonConvergedReason *reason) 385 { 386 PC_Telescope sred = (PC_Telescope)pc->data; 387 PetscErrorCode ierr; 388 Vec yred = NULL; 389 PetscBool default_init_guess_value = PETSC_FALSE; 390 PC_Telescope_CoarseDMCtx *ctx; 391 392 PetscFunctionBegin; 393 ctx = (PC_Telescope_CoarseDMCtx*)sred->dm_ctx; 394 yred = sred->yred; 395 396 if (its > 1) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PCApplyRichardson_Telescope_CoarseDM only supports max_it = 1"); 397 *reason = (PCRichardsonConvergedReason)0; 398 399 if (!zeroguess) { 400 ierr = PetscInfo(pc,"PCTelescopeCoarseDM: Scattering y for non-zero-initial guess\n");CHKERRQ(ierr); 401 402 ierr = ctx->fp_dm_field_scatter(ctx->dm_fine,y,SCATTER_FORWARD,ctx->dm_coarse,yred);CHKERRQ(ierr); 403 } 404 405 if (PCTelescope_isActiveRank(sred)) { 406 ierr = KSPGetInitialGuessNonzero(sred->ksp,&default_init_guess_value);CHKERRQ(ierr); 407 if (!zeroguess) {ierr = KSPSetInitialGuessNonzero(sred->ksp,PETSC_TRUE);CHKERRQ(ierr);} 408 } 409 410 ierr = PCApply_Telescope_CoarseDM(pc,x,y);CHKERRQ(ierr); 411 412 if (PCTelescope_isActiveRank(sred)) { 413 ierr = KSPSetInitialGuessNonzero(sred->ksp,default_init_guess_value);CHKERRQ(ierr); 414 } 415 416 if (!*reason) *reason = PCRICHARDSON_CONVERGED_ITS; 417 *outits = 1; 418 PetscFunctionReturn(0); 419 } 420