1 2 #include <petsc-private/pcimpl.h> /*I "petscpc.h" I*/ 3 #include <petscdm.h> 4 5 /* 6 There is a nice discussion of block preconditioners in 7 8 [El08] A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier–Stokes equations 9 Howard Elman, V.E. Howle, John Shadid, Robert Shuttleworth, Ray Tuminaro, Journal of Computational Physics 227 (2008) 1790--1808 10 http://chess.cs.umd.edu/~elman/papers/tax.pdf 11 */ 12 13 const char *const PCFieldSplitSchurPreTypes[] = {"SELF","A11","USER","PCFieldSplitSchurPreType","PC_FIELDSPLIT_SCHUR_PRE_",0}; 14 const char *const PCFieldSplitSchurFactTypes[] = {"DIAG","LOWER","UPPER","FULL","PCFieldSplitSchurFactType","PC_FIELDSPLIT_SCHUR_FACT_",0}; 15 16 typedef struct _PC_FieldSplitLink *PC_FieldSplitLink; 17 struct _PC_FieldSplitLink { 18 KSP ksp; 19 Vec x,y,z; 20 char *splitname; 21 PetscInt nfields; 22 PetscInt *fields,*fields_col; 23 VecScatter sctx; 24 IS is,is_col; 25 PC_FieldSplitLink next,previous; 26 }; 27 28 typedef struct { 29 PCCompositeType type; 30 PetscBool defaultsplit; /* Flag for a system with a set of 'k' scalar fields with the same layout (and bs = k) */ 31 PetscBool splitdefined; /* Flag is set after the splits have been defined, to prevent more splits from being added */ 32 PetscInt bs; /* Block size for IS and Mat structures */ 33 PetscInt nsplits; /* Number of field divisions defined */ 34 Vec *x,*y,w1,w2; 35 Mat *mat; /* The diagonal block for each split */ 36 Mat *pmat; /* The preconditioning diagonal block for each split */ 37 Mat *Afield; /* The rows of the matrix associated with each split */ 38 PetscBool issetup; 39 40 /* Only used when Schur complement preconditioning is used */ 41 Mat B; /* The (0,1) block */ 42 Mat C; /* The (1,0) block */ 43 Mat schur; /* The Schur complement S = A11 - A10 A00^{-1} A01, the KSP here, kspinner, is H_1 in [El08] */ 44 Mat schur_user; /* User-provided preconditioning matrix for the Schur complement */ 45 PCFieldSplitSchurPreType schurpre; /* Determines which preconditioning matrix is used for the Schur complement */ 46 PCFieldSplitSchurFactType schurfactorization; 47 KSP kspschur; /* The solver for S */ 48 KSP kspupper; /* The solver for A in the upper diagonal part of the factorization (H_2 in [El08]) */ 49 PC_FieldSplitLink head; 50 PetscBool reset; /* indicates PCReset() has been last called on this object, hack */ 51 PetscBool suboptionsset; /* Indicates that the KSPSetFromOptions() has been called on the sub-KSPs */ 52 PetscBool dm_splits; /* Whether to use DMCreateFieldDecomposition() whenever possible */ 53 } PC_FieldSplit; 54 55 /* 56 Notes: there is no particular reason that pmat, x, and y are stored as arrays in PC_FieldSplit instead of 57 inside PC_FieldSplitLink, just historical. If you want to be able to add new fields after already using the 58 PC you could change this. 59 */ 60 61 /* This helper is so that setting a user-provided preconditioning matrix is orthogonal to choosing to use it. This way the 62 * application-provided FormJacobian can provide this matrix without interfering with the user's (command-line) choices. */ 63 static Mat FieldSplitSchurPre(PC_FieldSplit *jac) 64 { 65 switch (jac->schurpre) { 66 case PC_FIELDSPLIT_SCHUR_PRE_SELF: return jac->schur; 67 case PC_FIELDSPLIT_SCHUR_PRE_A11: return jac->pmat[1]; 68 case PC_FIELDSPLIT_SCHUR_PRE_USER: /* Use a user-provided matrix if it is given, otherwise diagonal block */ 69 default: 70 return jac->schur_user ? jac->schur_user : jac->pmat[1]; 71 } 72 } 73 74 75 #include <petscdraw.h> 76 #undef __FUNCT__ 77 #define __FUNCT__ "PCView_FieldSplit" 78 static PetscErrorCode PCView_FieldSplit(PC pc,PetscViewer viewer) 79 { 80 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 81 PetscErrorCode ierr; 82 PetscBool iascii,isdraw; 83 PetscInt i,j; 84 PC_FieldSplitLink ilink = jac->head; 85 86 PetscFunctionBegin; 87 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr); 88 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr); 89 if (iascii) { 90 if (jac->bs > 0) { 91 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with %s composition: total splits = %D, blocksize = %D\n",PCCompositeTypes[jac->type],jac->nsplits,jac->bs);CHKERRQ(ierr); 92 } else { 93 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with %s composition: total splits = %D\n",PCCompositeTypes[jac->type],jac->nsplits);CHKERRQ(ierr); 94 } 95 if (pc->useAmat) { 96 ierr = PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for blocks\n");CHKERRQ(ierr); 97 } 98 ierr = PetscViewerASCIIPrintf(viewer," Solver info for each split is in the following KSP objects:\n");CHKERRQ(ierr); 99 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 100 for (i=0; i<jac->nsplits; i++) { 101 if (ilink->fields) { 102 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Fields ",i);CHKERRQ(ierr); 103 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr); 104 for (j=0; j<ilink->nfields; j++) { 105 if (j > 0) { 106 ierr = PetscViewerASCIIPrintf(viewer,",");CHKERRQ(ierr); 107 } 108 ierr = PetscViewerASCIIPrintf(viewer," %D",ilink->fields[j]);CHKERRQ(ierr); 109 } 110 ierr = PetscViewerASCIIPrintf(viewer,"\n");CHKERRQ(ierr); 111 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr); 112 } else { 113 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Defined by IS\n",i);CHKERRQ(ierr); 114 } 115 ierr = KSPView(ilink->ksp,viewer);CHKERRQ(ierr); 116 ilink = ilink->next; 117 } 118 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 119 } 120 121 if (isdraw) { 122 PetscDraw draw; 123 PetscReal x,y,w,wd; 124 125 ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr); 126 ierr = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr); 127 w = 2*PetscMin(1.0 - x,x); 128 wd = w/(jac->nsplits + 1); 129 x = x - wd*(jac->nsplits-1)/2.0; 130 for (i=0; i<jac->nsplits; i++) { 131 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 132 ierr = KSPView(ilink->ksp,viewer);CHKERRQ(ierr); 133 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 134 x += wd; 135 ilink = ilink->next; 136 } 137 } 138 PetscFunctionReturn(0); 139 } 140 141 #undef __FUNCT__ 142 #define __FUNCT__ "PCView_FieldSplit_Schur" 143 static PetscErrorCode PCView_FieldSplit_Schur(PC pc,PetscViewer viewer) 144 { 145 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 146 PetscErrorCode ierr; 147 PetscBool iascii,isdraw; 148 PetscInt i,j; 149 PC_FieldSplitLink ilink = jac->head; 150 151 PetscFunctionBegin; 152 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr); 153 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr); 154 if (iascii) { 155 if (jac->bs > 0) { 156 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with Schur preconditioner, blocksize = %D, factorization %s\n",jac->bs,PCFieldSplitSchurFactTypes[jac->schurfactorization]);CHKERRQ(ierr); 157 } else { 158 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with Schur preconditioner, factorization %s\n",PCFieldSplitSchurFactTypes[jac->schurfactorization]);CHKERRQ(ierr); 159 } 160 if (pc->useAmat) { 161 ierr = PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for blocks\n");CHKERRQ(ierr); 162 } 163 switch (jac->schurpre) { 164 case PC_FIELDSPLIT_SCHUR_PRE_SELF: 165 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from S itself\n");CHKERRQ(ierr);break; 166 case PC_FIELDSPLIT_SCHUR_PRE_A11: 167 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from A11\n");CHKERRQ(ierr);break; 168 case PC_FIELDSPLIT_SCHUR_PRE_USER: 169 if (jac->schur_user) { 170 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from user provided matrix\n");CHKERRQ(ierr); 171 } else { 172 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from A11\n");CHKERRQ(ierr); 173 } 174 break; 175 default: 176 SETERRQ1(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Invalid Schur preconditioning type: %d", jac->schurpre); 177 } 178 ierr = PetscViewerASCIIPrintf(viewer," Split info:\n");CHKERRQ(ierr); 179 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 180 for (i=0; i<jac->nsplits; i++) { 181 if (ilink->fields) { 182 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Fields ",i);CHKERRQ(ierr); 183 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr); 184 for (j=0; j<ilink->nfields; j++) { 185 if (j > 0) { 186 ierr = PetscViewerASCIIPrintf(viewer,",");CHKERRQ(ierr); 187 } 188 ierr = PetscViewerASCIIPrintf(viewer," %D",ilink->fields[j]);CHKERRQ(ierr); 189 } 190 ierr = PetscViewerASCIIPrintf(viewer,"\n");CHKERRQ(ierr); 191 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr); 192 } else { 193 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Defined by IS\n",i);CHKERRQ(ierr); 194 } 195 ilink = ilink->next; 196 } 197 ierr = PetscViewerASCIIPrintf(viewer,"KSP solver for A00 block \n");CHKERRQ(ierr); 198 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 199 ierr = KSPView(jac->head->ksp,viewer);CHKERRQ(ierr); 200 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 201 if (jac->kspupper != jac->head->ksp) { 202 ierr = PetscViewerASCIIPrintf(viewer,"KSP solver for upper A00 in upper triangular factor \n");CHKERRQ(ierr); 203 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 204 ierr = KSPView(jac->kspupper,viewer);CHKERRQ(ierr); 205 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 206 } 207 ierr = PetscViewerASCIIPrintf(viewer,"KSP solver for S = A11 - A10 inv(A00) A01 \n");CHKERRQ(ierr); 208 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 209 if (jac->kspschur) { 210 ierr = KSPView(jac->kspschur,viewer);CHKERRQ(ierr); 211 } else { 212 ierr = PetscViewerASCIIPrintf(viewer," not yet available\n");CHKERRQ(ierr); 213 } 214 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 215 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 216 } else if (isdraw) { 217 PetscDraw draw; 218 PetscReal x,y,w,wd,h; 219 PetscInt cnt = 2; 220 char str[32]; 221 222 ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr); 223 ierr = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr); 224 if (jac->kspupper != jac->head->ksp) cnt++; 225 w = 2*PetscMin(1.0 - x,x); 226 wd = w/(cnt + 1); 227 228 ierr = PetscSNPrintf(str,32,"Schur fact. %s",PCFieldSplitSchurFactTypes[jac->schurfactorization]);CHKERRQ(ierr); 229 ierr = PetscDrawBoxedString(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);CHKERRQ(ierr); 230 y -= h; 231 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_USER && !jac->schur_user) { 232 ierr = PetscSNPrintf(str,32,"Prec. for Schur from %s",PCFieldSplitSchurPreTypes[PC_FIELDSPLIT_SCHUR_PRE_A11]);CHKERRQ(ierr); 233 } else { 234 ierr = PetscSNPrintf(str,32,"Prec. for Schur from %s",PCFieldSplitSchurPreTypes[jac->schurpre]);CHKERRQ(ierr); 235 } 236 ierr = PetscDrawBoxedString(draw,x+wd*(cnt-1)/2.0,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);CHKERRQ(ierr); 237 y -= h; 238 x = x - wd*(cnt-1)/2.0; 239 240 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 241 ierr = KSPView(jac->head->ksp,viewer);CHKERRQ(ierr); 242 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 243 if (jac->kspupper != jac->head->ksp) { 244 x += wd; 245 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 246 ierr = KSPView(jac->kspupper,viewer);CHKERRQ(ierr); 247 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 248 } 249 x += wd; 250 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 251 ierr = KSPView(jac->kspschur,viewer);CHKERRQ(ierr); 252 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 253 } 254 PetscFunctionReturn(0); 255 } 256 257 #undef __FUNCT__ 258 #define __FUNCT__ "PCFieldSplitSetRuntimeSplits_Private" 259 /* Precondition: jac->bs is set to a meaningful value */ 260 static PetscErrorCode PCFieldSplitSetRuntimeSplits_Private(PC pc) 261 { 262 PetscErrorCode ierr; 263 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 264 PetscInt i,nfields,*ifields,nfields_col,*ifields_col; 265 PetscBool flg,flg_col; 266 char optionname[128],splitname[8],optionname_col[128]; 267 268 PetscFunctionBegin; 269 ierr = PetscMalloc(jac->bs*sizeof(PetscInt),&ifields);CHKERRQ(ierr); 270 ierr = PetscMalloc(jac->bs*sizeof(PetscInt),&ifields_col);CHKERRQ(ierr); 271 for (i=0,flg=PETSC_TRUE;; i++) { 272 ierr = PetscSNPrintf(splitname,sizeof(splitname),"%D",i);CHKERRQ(ierr); 273 ierr = PetscSNPrintf(optionname,sizeof(optionname),"-pc_fieldsplit_%D_fields",i);CHKERRQ(ierr); 274 ierr = PetscSNPrintf(optionname_col,sizeof(optionname_col),"-pc_fieldsplit_%D_fields_col",i);CHKERRQ(ierr); 275 nfields = jac->bs; 276 nfields_col = jac->bs; 277 ierr = PetscOptionsGetIntArray(((PetscObject)pc)->prefix,optionname,ifields,&nfields,&flg);CHKERRQ(ierr); 278 ierr = PetscOptionsGetIntArray(((PetscObject)pc)->prefix,optionname_col,ifields_col,&nfields_col,&flg_col);CHKERRQ(ierr); 279 if (!flg) break; 280 else if (flg && !flg_col) { 281 if (!nfields) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot list zero fields"); 282 ierr = PCFieldSplitSetFields(pc,splitname,nfields,ifields,ifields);CHKERRQ(ierr); 283 } else { 284 if (!nfields || !nfields_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot list zero fields"); 285 if (nfields != nfields_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Number of row and column fields must match"); 286 ierr = PCFieldSplitSetFields(pc,splitname,nfields,ifields,ifields_col);CHKERRQ(ierr); 287 } 288 } 289 if (i > 0) { 290 /* Makes command-line setting of splits take precedence over setting them in code. 291 Otherwise subsequent calls to PCFieldSplitSetIS() or PCFieldSplitSetFields() would 292 create new splits, which would probably not be what the user wanted. */ 293 jac->splitdefined = PETSC_TRUE; 294 } 295 ierr = PetscFree(ifields);CHKERRQ(ierr); 296 ierr = PetscFree(ifields_col);CHKERRQ(ierr); 297 PetscFunctionReturn(0); 298 } 299 300 #undef __FUNCT__ 301 #define __FUNCT__ "PCFieldSplitSetDefaults" 302 static PetscErrorCode PCFieldSplitSetDefaults(PC pc) 303 { 304 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 305 PetscErrorCode ierr; 306 PC_FieldSplitLink ilink = jac->head; 307 PetscBool fieldsplit_default = PETSC_FALSE,stokes = PETSC_FALSE; 308 PetscInt i; 309 310 PetscFunctionBegin; 311 /* 312 Kinda messy, but at least this now uses DMCreateFieldDecomposition() even with jac->reset. 313 Should probably be rewritten. 314 */ 315 if (!ilink || jac->reset) { 316 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr); 317 if (pc->dm && jac->dm_splits && !stokes) { 318 PetscInt numFields, f, i, j; 319 char **fieldNames; 320 IS *fields; 321 DM *dms; 322 DM subdm[128]; 323 PetscBool flg; 324 325 ierr = DMCreateFieldDecomposition(pc->dm, &numFields, &fieldNames, &fields, &dms);CHKERRQ(ierr); 326 /* Allow the user to prescribe the splits */ 327 for (i = 0, flg = PETSC_TRUE;; i++) { 328 PetscInt ifields[128]; 329 IS compField; 330 char optionname[128], splitname[8]; 331 PetscInt nfields = numFields; 332 333 ierr = PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%D_fields", i);CHKERRQ(ierr); 334 ierr = PetscOptionsGetIntArray(((PetscObject) pc)->prefix, optionname, ifields, &nfields, &flg);CHKERRQ(ierr); 335 if (!flg) break; 336 if (numFields > 128) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot currently support %d > 128 fields", numFields); 337 ierr = DMCreateSubDM(pc->dm, nfields, ifields, &compField, &subdm[i]);CHKERRQ(ierr); 338 if (nfields == 1) { 339 ierr = PCFieldSplitSetIS(pc, fieldNames[ifields[0]], compField);CHKERRQ(ierr); 340 /* ierr = PetscPrintf(PetscObjectComm((PetscObject)pc), "%s Field Indices:", fieldNames[ifields[0]]);CHKERRQ(ierr); 341 ierr = ISView(compField, NULL);CHKERRQ(ierr); */ 342 } else { 343 ierr = PetscSNPrintf(splitname, sizeof(splitname), "%D", i);CHKERRQ(ierr); 344 ierr = PCFieldSplitSetIS(pc, splitname, compField);CHKERRQ(ierr); 345 /* ierr = PetscPrintf(PetscObjectComm((PetscObject)pc), "%s Field Indices:", splitname);CHKERRQ(ierr); 346 ierr = ISView(compField, NULL);CHKERRQ(ierr); */ 347 } 348 ierr = ISDestroy(&compField);CHKERRQ(ierr); 349 for (j = 0; j < nfields; ++j) { 350 f = ifields[j]; 351 ierr = PetscFree(fieldNames[f]);CHKERRQ(ierr); 352 ierr = ISDestroy(&fields[f]);CHKERRQ(ierr); 353 } 354 } 355 if (i == 0) { 356 for (f = 0; f < numFields; ++f) { 357 ierr = PCFieldSplitSetIS(pc, fieldNames[f], fields[f]);CHKERRQ(ierr); 358 ierr = PetscFree(fieldNames[f]);CHKERRQ(ierr); 359 ierr = ISDestroy(&fields[f]);CHKERRQ(ierr); 360 } 361 } else { 362 for (j=0; j<numFields; j++) { 363 ierr = DMDestroy(dms+j);CHKERRQ(ierr); 364 } 365 ierr = PetscFree(dms);CHKERRQ(ierr); 366 ierr = PetscMalloc(i * sizeof(DM), &dms);CHKERRQ(ierr); 367 for (j = 0; j < i; ++j) dms[j] = subdm[j]; 368 } 369 ierr = PetscFree(fieldNames);CHKERRQ(ierr); 370 ierr = PetscFree(fields);CHKERRQ(ierr); 371 if (dms) { 372 ierr = PetscInfo(pc, "Setting up physics based fieldsplit preconditioner using the embedded DM\n");CHKERRQ(ierr); 373 for (ilink = jac->head, i = 0; ilink; ilink = ilink->next, ++i) { 374 const char *prefix; 375 ierr = PetscObjectGetOptionsPrefix((PetscObject)(ilink->ksp),&prefix);CHKERRQ(ierr); 376 ierr = PetscObjectSetOptionsPrefix((PetscObject)(dms[i]), prefix);CHKERRQ(ierr); 377 ierr = KSPSetDM(ilink->ksp, dms[i]);CHKERRQ(ierr); 378 ierr = KSPSetDMActive(ilink->ksp, PETSC_FALSE);CHKERRQ(ierr); 379 ierr = PetscObjectIncrementTabLevel((PetscObject)dms[i],(PetscObject)ilink->ksp,0);CHKERRQ(ierr); 380 ierr = DMDestroy(&dms[i]);CHKERRQ(ierr); 381 } 382 ierr = PetscFree(dms);CHKERRQ(ierr); 383 } 384 } else { 385 if (jac->bs <= 0) { 386 if (pc->pmat) { 387 ierr = MatGetBlockSize(pc->pmat,&jac->bs);CHKERRQ(ierr); 388 } else jac->bs = 1; 389 } 390 391 if (stokes) { 392 IS zerodiags,rest; 393 PetscInt nmin,nmax; 394 395 ierr = MatGetOwnershipRange(pc->mat,&nmin,&nmax);CHKERRQ(ierr); 396 ierr = MatFindZeroDiagonals(pc->mat,&zerodiags);CHKERRQ(ierr); 397 ierr = ISComplement(zerodiags,nmin,nmax,&rest);CHKERRQ(ierr); 398 if (jac->reset) { 399 jac->head->is = rest; 400 jac->head->next->is = zerodiags; 401 } else { 402 ierr = PCFieldSplitSetIS(pc,"0",rest);CHKERRQ(ierr); 403 ierr = PCFieldSplitSetIS(pc,"1",zerodiags);CHKERRQ(ierr); 404 } 405 ierr = ISDestroy(&zerodiags);CHKERRQ(ierr); 406 ierr = ISDestroy(&rest);CHKERRQ(ierr); 407 } else { 408 if (jac->reset) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cases not yet handled when PCReset() was used"); 409 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_default",&fieldsplit_default,NULL);CHKERRQ(ierr); 410 if (!fieldsplit_default) { 411 /* Allow user to set fields from command line, if bs was known at the time of PCSetFromOptions_FieldSplit() 412 then it is set there. This is not ideal because we should only have options set in XXSetFromOptions(). */ 413 ierr = PCFieldSplitSetRuntimeSplits_Private(pc);CHKERRQ(ierr); 414 if (jac->splitdefined) {ierr = PetscInfo(pc,"Splits defined using the options database\n");CHKERRQ(ierr);} 415 } 416 if (fieldsplit_default || !jac->splitdefined) { 417 ierr = PetscInfo(pc,"Using default splitting of fields\n");CHKERRQ(ierr); 418 for (i=0; i<jac->bs; i++) { 419 char splitname[8]; 420 ierr = PetscSNPrintf(splitname,sizeof(splitname),"%D",i);CHKERRQ(ierr); 421 ierr = PCFieldSplitSetFields(pc,splitname,1,&i,&i);CHKERRQ(ierr); 422 } 423 jac->defaultsplit = PETSC_TRUE; 424 } 425 } 426 } 427 } else if (jac->nsplits == 1) { 428 if (ilink->is) { 429 IS is2; 430 PetscInt nmin,nmax; 431 432 ierr = MatGetOwnershipRange(pc->mat,&nmin,&nmax);CHKERRQ(ierr); 433 ierr = ISComplement(ilink->is,nmin,nmax,&is2);CHKERRQ(ierr); 434 ierr = PCFieldSplitSetIS(pc,"1",is2);CHKERRQ(ierr); 435 ierr = ISDestroy(&is2);CHKERRQ(ierr); 436 } else SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Must provide at least two sets of fields to PCFieldSplit()"); 437 } 438 439 440 if (jac->nsplits < 2) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_PLIB,"Unhandled case, must have at least two fields, not %d", jac->nsplits); 441 PetscFunctionReturn(0); 442 } 443 444 PETSC_EXTERN PetscErrorCode PetscOptionsFindPairPrefix_Private(const char pre[], const char name[], char *value[], PetscBool *flg); 445 446 #undef __FUNCT__ 447 #define __FUNCT__ "PCSetUp_FieldSplit" 448 static PetscErrorCode PCSetUp_FieldSplit(PC pc) 449 { 450 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 451 PetscErrorCode ierr; 452 PC_FieldSplitLink ilink; 453 PetscInt i,nsplit; 454 MatStructure flag = pc->flag; 455 PetscBool sorted, sorted_col; 456 457 PetscFunctionBegin; 458 ierr = PCFieldSplitSetDefaults(pc);CHKERRQ(ierr); 459 nsplit = jac->nsplits; 460 ilink = jac->head; 461 462 /* get the matrices for each split */ 463 if (!jac->issetup) { 464 PetscInt rstart,rend,nslots,bs; 465 466 jac->issetup = PETSC_TRUE; 467 468 /* This is done here instead of in PCFieldSplitSetFields() because may not have matrix at that point */ 469 if (jac->defaultsplit || !ilink->is) { 470 if (jac->bs <= 0) jac->bs = nsplit; 471 } 472 bs = jac->bs; 473 ierr = MatGetOwnershipRange(pc->pmat,&rstart,&rend);CHKERRQ(ierr); 474 nslots = (rend - rstart)/bs; 475 for (i=0; i<nsplit; i++) { 476 if (jac->defaultsplit) { 477 ierr = ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+i,nsplit,&ilink->is);CHKERRQ(ierr); 478 ierr = ISDuplicate(ilink->is,&ilink->is_col);CHKERRQ(ierr); 479 } else if (!ilink->is) { 480 if (ilink->nfields > 1) { 481 PetscInt *ii,*jj,j,k,nfields = ilink->nfields,*fields = ilink->fields,*fields_col = ilink->fields_col; 482 ierr = PetscMalloc(ilink->nfields*nslots*sizeof(PetscInt),&ii);CHKERRQ(ierr); 483 ierr = PetscMalloc(ilink->nfields*nslots*sizeof(PetscInt),&jj);CHKERRQ(ierr); 484 for (j=0; j<nslots; j++) { 485 for (k=0; k<nfields; k++) { 486 ii[nfields*j + k] = rstart + bs*j + fields[k]; 487 jj[nfields*j + k] = rstart + bs*j + fields_col[k]; 488 } 489 } 490 ierr = ISCreateGeneral(PetscObjectComm((PetscObject)pc),nslots*nfields,ii,PETSC_OWN_POINTER,&ilink->is);CHKERRQ(ierr); 491 ierr = ISCreateGeneral(PetscObjectComm((PetscObject)pc),nslots*nfields,jj,PETSC_OWN_POINTER,&ilink->is_col);CHKERRQ(ierr); 492 } else { 493 ierr = ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+ilink->fields[0],bs,&ilink->is);CHKERRQ(ierr); 494 ierr = ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+ilink->fields_col[0],bs,&ilink->is_col);CHKERRQ(ierr); 495 } 496 } 497 ierr = ISSorted(ilink->is,&sorted);CHKERRQ(ierr); 498 if (ilink->is_col) { ierr = ISSorted(ilink->is_col,&sorted_col);CHKERRQ(ierr); } 499 if (!sorted || !sorted_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Fields must be sorted when creating split"); 500 ilink = ilink->next; 501 } 502 } 503 504 ilink = jac->head; 505 if (!jac->pmat) { 506 Vec xtmp; 507 508 ierr = MatGetVecs(pc->pmat,&xtmp,NULL);CHKERRQ(ierr); 509 ierr = PetscMalloc(nsplit*sizeof(Mat),&jac->pmat);CHKERRQ(ierr); 510 ierr = PetscMalloc2(nsplit,Vec,&jac->x,nsplit,Vec,&jac->y);CHKERRQ(ierr); 511 for (i=0; i<nsplit; i++) { 512 MatNullSpace sp; 513 514 /* Check for preconditioning matrix attached to IS */ 515 ierr = PetscObjectQuery((PetscObject) ilink->is, "pmat", (PetscObject*) &jac->pmat[i]);CHKERRQ(ierr); 516 if (jac->pmat[i]) { 517 ierr = PetscObjectReference((PetscObject) jac->pmat[i]);CHKERRQ(ierr); 518 if (jac->type == PC_COMPOSITE_SCHUR) { 519 jac->schur_user = jac->pmat[i]; 520 521 ierr = PetscObjectReference((PetscObject) jac->schur_user);CHKERRQ(ierr); 522 } 523 } else { 524 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ilink->is_col,MAT_INITIAL_MATRIX,&jac->pmat[i]);CHKERRQ(ierr); 525 } 526 /* create work vectors for each split */ 527 ierr = MatGetVecs(jac->pmat[i],&jac->x[i],&jac->y[i]);CHKERRQ(ierr); 528 ilink->x = jac->x[i]; ilink->y = jac->y[i]; ilink->z = NULL; 529 /* compute scatter contexts needed by multiplicative versions and non-default splits */ 530 ierr = VecScatterCreate(xtmp,ilink->is,jac->x[i],NULL,&ilink->sctx);CHKERRQ(ierr); 531 /* Check for null space attached to IS */ 532 ierr = PetscObjectQuery((PetscObject) ilink->is, "nullspace", (PetscObject*) &sp);CHKERRQ(ierr); 533 if (sp) { 534 ierr = MatSetNullSpace(jac->pmat[i], sp);CHKERRQ(ierr); 535 } 536 ierr = PetscObjectQuery((PetscObject) ilink->is, "nearnullspace", (PetscObject*) &sp);CHKERRQ(ierr); 537 if (sp) { 538 ierr = MatSetNearNullSpace(jac->pmat[i], sp);CHKERRQ(ierr); 539 } 540 ilink = ilink->next; 541 } 542 ierr = VecDestroy(&xtmp);CHKERRQ(ierr); 543 } else { 544 for (i=0; i<nsplit; i++) { 545 Mat pmat; 546 547 /* Check for preconditioning matrix attached to IS */ 548 ierr = PetscObjectQuery((PetscObject) ilink->is, "pmat", (PetscObject*) &pmat);CHKERRQ(ierr); 549 if (!pmat) { 550 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ilink->is_col,MAT_REUSE_MATRIX,&jac->pmat[i]);CHKERRQ(ierr); 551 } 552 ilink = ilink->next; 553 } 554 } 555 if (pc->useAmat) { 556 ilink = jac->head; 557 if (!jac->mat) { 558 ierr = PetscMalloc(nsplit*sizeof(Mat),&jac->mat);CHKERRQ(ierr); 559 for (i=0; i<nsplit; i++) { 560 ierr = MatGetSubMatrix(pc->mat,ilink->is,ilink->is_col,MAT_INITIAL_MATRIX,&jac->mat[i]);CHKERRQ(ierr); 561 ilink = ilink->next; 562 } 563 } else { 564 for (i=0; i<nsplit; i++) { 565 if (jac->mat[i]) {ierr = MatGetSubMatrix(pc->mat,ilink->is,ilink->is_col,MAT_REUSE_MATRIX,&jac->mat[i]);CHKERRQ(ierr);} 566 ilink = ilink->next; 567 } 568 } 569 } else { 570 jac->mat = jac->pmat; 571 } 572 573 if (jac->type != PC_COMPOSITE_ADDITIVE && jac->type != PC_COMPOSITE_SCHUR) { 574 /* extract the rows of the matrix associated with each field: used for efficient computation of residual inside algorithm */ 575 ilink = jac->head; 576 if (!jac->Afield) { 577 ierr = PetscMalloc(nsplit*sizeof(Mat),&jac->Afield);CHKERRQ(ierr); 578 for (i=0; i<nsplit; i++) { 579 ierr = MatGetSubMatrix(pc->mat,ilink->is,NULL,MAT_INITIAL_MATRIX,&jac->Afield[i]);CHKERRQ(ierr); 580 ilink = ilink->next; 581 } 582 } else { 583 for (i=0; i<nsplit; i++) { 584 ierr = MatGetSubMatrix(pc->mat,ilink->is,NULL,MAT_REUSE_MATRIX,&jac->Afield[i]);CHKERRQ(ierr); 585 ilink = ilink->next; 586 } 587 } 588 } 589 590 if (jac->type == PC_COMPOSITE_SCHUR) { 591 IS ccis; 592 PetscInt rstart,rend; 593 char lscname[256]; 594 PetscObject LSC_L; 595 596 if (nsplit != 2) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_INCOMP,"To use Schur complement preconditioner you must have exactly 2 fields"); 597 598 /* When extracting off-diagonal submatrices, we take complements from this range */ 599 ierr = MatGetOwnershipRangeColumn(pc->mat,&rstart,&rend);CHKERRQ(ierr); 600 601 /* need to handle case when one is resetting up the preconditioner */ 602 if (jac->schur) { 603 KSP kspA = jac->head->ksp, kspInner = NULL, kspUpper = jac->kspupper; 604 605 ierr = MatSchurComplementGetKSP(jac->schur, &kspInner);CHKERRQ(ierr); 606 ilink = jac->head; 607 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 608 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->B);CHKERRQ(ierr); 609 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 610 ilink = ilink->next; 611 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 612 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->C);CHKERRQ(ierr); 613 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 614 ierr = MatSchurComplementUpdate(jac->schur,jac->mat[0],jac->pmat[0],jac->B,jac->C,jac->mat[1],pc->flag);CHKERRQ(ierr); 615 if (kspA != kspInner) { 616 ierr = KSPSetOperators(kspA,jac->mat[0],jac->pmat[0],pc->flag);CHKERRQ(ierr); 617 } 618 if (kspUpper != kspA) { 619 ierr = KSPSetOperators(kspUpper,jac->mat[0],jac->pmat[0],pc->flag);CHKERRQ(ierr); 620 } 621 ierr = KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac),pc->flag);CHKERRQ(ierr); 622 } else { 623 KSP ksp; 624 const char *Dprefix; 625 char schurprefix[256]; 626 char schurtestoption[256]; 627 MatNullSpace sp; 628 PetscBool flg; 629 630 /* extract the A01 and A10 matrices */ 631 ilink = jac->head; 632 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 633 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->B);CHKERRQ(ierr); 634 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 635 ilink = ilink->next; 636 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 637 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->C);CHKERRQ(ierr); 638 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 639 640 /* Use mat[0] (diagonal block of Amat) preconditioned by pmat[0] to define Schur complement */ 641 ierr = MatCreate(((PetscObject)jac->mat[0])->comm,&jac->schur);CHKERRQ(ierr); 642 ierr = MatSetType(jac->schur,MATSCHURCOMPLEMENT);CHKERRQ(ierr); 643 ierr = MatSchurComplementGetKSP(jac->schur, &ksp);CHKERRQ(ierr); 644 ierr = PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_inner_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);CHKERRQ(ierr); 645 /* Indent this deeper to emphasize the "inner" nature of this solver. */ 646 ierr = PetscObjectIncrementTabLevel((PetscObject)ksp, (PetscObject) pc, 2);CHKERRQ(ierr); 647 ierr = KSPSetOptionsPrefix(ksp, schurprefix);CHKERRQ(ierr); 648 ierr = MatSchurComplementSet(jac->schur,jac->mat[0],jac->pmat[0],jac->B,jac->C,jac->mat[1]);CHKERRQ(ierr); 649 650 ierr = MatGetNullSpace(jac->pmat[1], &sp);CHKERRQ(ierr); 651 if (sp) { 652 ierr = MatSetNullSpace(jac->schur, sp);CHKERRQ(ierr); 653 } 654 655 ierr = PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_inner_", ilink->splitname);CHKERRQ(ierr); 656 ierr = PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->prefix, schurtestoption, NULL, &flg);CHKERRQ(ierr); 657 if (flg) { 658 DM dmInner; 659 660 /* Set DM for new solver */ 661 ierr = KSPGetDM(jac->head->ksp, &dmInner);CHKERRQ(ierr); 662 ierr = KSPSetDM(ksp, dmInner);CHKERRQ(ierr); 663 ierr = KSPSetDMActive(ksp, PETSC_FALSE);CHKERRQ(ierr); 664 ierr = KSPSetOperators(jac->head->ksp,jac->mat[0],jac->pmat[0],flag);CHKERRQ(ierr); 665 ierr = KSPSetFromOptions(jac->head->ksp);CHKERRQ(ierr); 666 } else { 667 ierr = MatSchurComplementSetKSP(jac->schur, jac->head->ksp);CHKERRQ(ierr); 668 ierr = PetscObjectReference((PetscObject) jac->head->ksp);CHKERRQ(ierr); 669 } 670 ierr = MatSetFromOptions(jac->schur);CHKERRQ(ierr); 671 672 ierr = PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_upper_", ilink->splitname);CHKERRQ(ierr); 673 ierr = PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->prefix, schurtestoption, NULL, &flg);CHKERRQ(ierr); 674 if (flg) { 675 DM dmInner; 676 677 ierr = PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_upper_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);CHKERRQ(ierr); 678 ierr = KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspupper);CHKERRQ(ierr); 679 ierr = KSPSetOptionsPrefix(jac->kspupper, schurprefix);CHKERRQ(ierr); 680 ierr = KSPGetDM(jac->head->ksp, &dmInner);CHKERRQ(ierr); 681 ierr = KSPSetDM(jac->kspupper, dmInner);CHKERRQ(ierr); 682 ierr = KSPSetDMActive(jac->kspupper, PETSC_FALSE);CHKERRQ(ierr); 683 ierr = KSPSetFromOptions(jac->kspupper);CHKERRQ(ierr); 684 ierr = KSPSetOperators(jac->kspupper,jac->mat[0],jac->pmat[0],flag);CHKERRQ(ierr); 685 ierr = VecDuplicate(jac->head->x, &jac->head->z);CHKERRQ(ierr); 686 } else { 687 jac->kspupper = jac->head->ksp; 688 ierr = PetscObjectReference((PetscObject) jac->head->ksp);CHKERRQ(ierr); 689 } 690 691 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&jac->kspschur);CHKERRQ(ierr); 692 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)jac->kspschur);CHKERRQ(ierr); 693 ierr = PetscObjectIncrementTabLevel((PetscObject)jac->kspschur,(PetscObject)pc,1);CHKERRQ(ierr); 694 ierr = KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac),DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr); 695 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) { 696 PC pcschur; 697 ierr = KSPGetPC(jac->kspschur,&pcschur);CHKERRQ(ierr); 698 ierr = PCSetType(pcschur,PCNONE);CHKERRQ(ierr); 699 /* Note: This is bad if there exist preconditioners for MATSCHURCOMPLEMENT */ 700 } 701 ierr = KSPGetOptionsPrefix(jac->head->next->ksp, &Dprefix);CHKERRQ(ierr); 702 ierr = KSPSetOptionsPrefix(jac->kspschur, Dprefix);CHKERRQ(ierr); 703 /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */ 704 /* need to call this every time, since the jac->kspschur is freshly created, otherwise its options never get set */ 705 ierr = KSPSetFromOptions(jac->kspschur);CHKERRQ(ierr); 706 } 707 708 /* HACK: special support to forward L and Lp matrices that might be used by PCLSC */ 709 ierr = PetscSNPrintf(lscname,sizeof(lscname),"%s_LSC_L",ilink->splitname);CHKERRQ(ierr); 710 ierr = PetscObjectQuery((PetscObject)pc->mat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr); 711 if (!LSC_L) {ierr = PetscObjectQuery((PetscObject)pc->pmat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr);} 712 if (LSC_L) {ierr = PetscObjectCompose((PetscObject)jac->schur,"LSC_L",(PetscObject)LSC_L);CHKERRQ(ierr);} 713 ierr = PetscSNPrintf(lscname,sizeof(lscname),"%s_LSC_Lp",ilink->splitname);CHKERRQ(ierr); 714 ierr = PetscObjectQuery((PetscObject)pc->pmat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr); 715 if (!LSC_L) {ierr = PetscObjectQuery((PetscObject)pc->mat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr);} 716 if (LSC_L) {ierr = PetscObjectCompose((PetscObject)jac->schur,"LSC_Lp",(PetscObject)LSC_L);CHKERRQ(ierr);} 717 } else { 718 /* set up the individual splits' PCs */ 719 i = 0; 720 ilink = jac->head; 721 while (ilink) { 722 ierr = KSPSetOperators(ilink->ksp,jac->mat[i],jac->pmat[i],flag);CHKERRQ(ierr); 723 /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */ 724 if (!jac->suboptionsset) {ierr = KSPSetFromOptions(ilink->ksp);CHKERRQ(ierr);} 725 i++; 726 ilink = ilink->next; 727 } 728 } 729 730 jac->suboptionsset = PETSC_TRUE; 731 PetscFunctionReturn(0); 732 } 733 734 #define FieldSplitSplitSolveAdd(ilink,xx,yy) \ 735 (VecScatterBegin(ilink->sctx,xx,ilink->x,INSERT_VALUES,SCATTER_FORWARD) || \ 736 VecScatterEnd(ilink->sctx,xx,ilink->x,INSERT_VALUES,SCATTER_FORWARD) || \ 737 KSPSolve(ilink->ksp,ilink->x,ilink->y) || \ 738 VecScatterBegin(ilink->sctx,ilink->y,yy,ADD_VALUES,SCATTER_REVERSE) || \ 739 VecScatterEnd(ilink->sctx,ilink->y,yy,ADD_VALUES,SCATTER_REVERSE)) 740 741 #undef __FUNCT__ 742 #define __FUNCT__ "PCApply_FieldSplit_Schur" 743 static PetscErrorCode PCApply_FieldSplit_Schur(PC pc,Vec x,Vec y) 744 { 745 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 746 PetscErrorCode ierr; 747 PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next; 748 KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper; 749 750 PetscFunctionBegin; 751 switch (jac->schurfactorization) { 752 case PC_FIELDSPLIT_SCHUR_FACT_DIAG: 753 /* [A00 0; 0 -S], positive definite, suitable for MINRES */ 754 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 755 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 756 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 757 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 758 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 759 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 760 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 761 ierr = VecScale(ilinkD->y,-1.);CHKERRQ(ierr); 762 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 763 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 764 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 765 break; 766 case PC_FIELDSPLIT_SCHUR_FACT_LOWER: 767 /* [A00 0; A10 S], suitable for left preconditioning */ 768 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 769 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 770 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 771 ierr = MatMult(jac->C,ilinkA->y,ilinkD->x);CHKERRQ(ierr); 772 ierr = VecScale(ilinkD->x,-1.);CHKERRQ(ierr); 773 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 774 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 775 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 776 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 777 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 778 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 779 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 780 break; 781 case PC_FIELDSPLIT_SCHUR_FACT_UPPER: 782 /* [A00 A01; 0 S], suitable for right preconditioning */ 783 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 784 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 785 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 786 ierr = MatMult(jac->B,ilinkD->y,ilinkA->x);CHKERRQ(ierr); 787 ierr = VecScale(ilinkA->x,-1.);CHKERRQ(ierr); 788 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 789 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 790 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 791 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 792 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 793 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 794 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 795 break; 796 case PC_FIELDSPLIT_SCHUR_FACT_FULL: 797 /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1], an exact solve if applied exactly, needs one extra solve with A */ 798 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 799 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 800 ierr = KSPSolve(kspLower,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 801 ierr = MatMult(jac->C,ilinkA->y,ilinkD->x);CHKERRQ(ierr); 802 ierr = VecScale(ilinkD->x,-1.0);CHKERRQ(ierr); 803 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 804 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 805 806 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 807 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 808 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 809 810 if (kspUpper == kspA) { 811 ierr = MatMult(jac->B,ilinkD->y,ilinkA->y);CHKERRQ(ierr); 812 ierr = VecAXPY(ilinkA->x,-1.0,ilinkA->y);CHKERRQ(ierr); 813 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 814 } else { 815 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 816 ierr = MatMult(jac->B,ilinkD->y,ilinkA->x);CHKERRQ(ierr); 817 ierr = KSPSolve(kspUpper,ilinkA->x,ilinkA->z);CHKERRQ(ierr); 818 ierr = VecAXPY(ilinkA->y,-1.0,ilinkA->z);CHKERRQ(ierr); 819 } 820 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 821 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 822 } 823 PetscFunctionReturn(0); 824 } 825 826 #undef __FUNCT__ 827 #define __FUNCT__ "PCApply_FieldSplit" 828 static PetscErrorCode PCApply_FieldSplit(PC pc,Vec x,Vec y) 829 { 830 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 831 PetscErrorCode ierr; 832 PC_FieldSplitLink ilink = jac->head; 833 PetscInt cnt,bs; 834 835 PetscFunctionBegin; 836 CHKMEMQ; 837 if (jac->type == PC_COMPOSITE_ADDITIVE) { 838 if (jac->defaultsplit) { 839 ierr = VecGetBlockSize(x,&bs);CHKERRQ(ierr); 840 if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of x vector %D does not match fieldsplit blocksize %D",bs,jac->bs); 841 ierr = VecGetBlockSize(y,&bs);CHKERRQ(ierr); 842 if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of y vector %D does not match fieldsplit blocksize %D",bs,jac->bs); 843 ierr = VecStrideGatherAll(x,jac->x,INSERT_VALUES);CHKERRQ(ierr); 844 while (ilink) { 845 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 846 ilink = ilink->next; 847 } 848 ierr = VecStrideScatterAll(jac->y,y,INSERT_VALUES);CHKERRQ(ierr); 849 } else { 850 ierr = VecSet(y,0.0);CHKERRQ(ierr); 851 while (ilink) { 852 ierr = FieldSplitSplitSolveAdd(ilink,x,y);CHKERRQ(ierr); 853 ilink = ilink->next; 854 } 855 } 856 } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 857 if (!jac->w1) { 858 ierr = VecDuplicate(x,&jac->w1);CHKERRQ(ierr); 859 ierr = VecDuplicate(x,&jac->w2);CHKERRQ(ierr); 860 } 861 ierr = VecSet(y,0.0);CHKERRQ(ierr); 862 ierr = FieldSplitSplitSolveAdd(ilink,x,y);CHKERRQ(ierr); 863 cnt = 1; 864 while (ilink->next) { 865 ilink = ilink->next; 866 /* compute the residual only over the part of the vector needed */ 867 ierr = MatMult(jac->Afield[cnt++],y,ilink->x);CHKERRQ(ierr); 868 ierr = VecScale(ilink->x,-1.0);CHKERRQ(ierr); 869 ierr = VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 870 ierr = VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 871 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 872 ierr = VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 873 ierr = VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 874 } 875 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 876 cnt -= 2; 877 while (ilink->previous) { 878 ilink = ilink->previous; 879 /* compute the residual only over the part of the vector needed */ 880 ierr = MatMult(jac->Afield[cnt--],y,ilink->x);CHKERRQ(ierr); 881 ierr = VecScale(ilink->x,-1.0);CHKERRQ(ierr); 882 ierr = VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 883 ierr = VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 884 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 885 ierr = VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 886 ierr = VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 887 } 888 } 889 } else SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Unsupported or unknown composition",(int) jac->type); 890 CHKMEMQ; 891 PetscFunctionReturn(0); 892 } 893 894 #define FieldSplitSplitSolveAddTranspose(ilink,xx,yy) \ 895 (VecScatterBegin(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \ 896 VecScatterEnd(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \ 897 KSPSolveTranspose(ilink->ksp,ilink->y,ilink->x) || \ 898 VecScatterBegin(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE) || \ 899 VecScatterEnd(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE)) 900 901 #undef __FUNCT__ 902 #define __FUNCT__ "PCApplyTranspose_FieldSplit" 903 static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc,Vec x,Vec y) 904 { 905 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 906 PetscErrorCode ierr; 907 PC_FieldSplitLink ilink = jac->head; 908 PetscInt bs; 909 910 PetscFunctionBegin; 911 CHKMEMQ; 912 if (jac->type == PC_COMPOSITE_ADDITIVE) { 913 if (jac->defaultsplit) { 914 ierr = VecGetBlockSize(x,&bs);CHKERRQ(ierr); 915 if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of x vector %D does not match fieldsplit blocksize %D",bs,jac->bs); 916 ierr = VecGetBlockSize(y,&bs);CHKERRQ(ierr); 917 if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of y vector %D does not match fieldsplit blocksize %D",bs,jac->bs); 918 ierr = VecStrideGatherAll(x,jac->x,INSERT_VALUES);CHKERRQ(ierr); 919 while (ilink) { 920 ierr = KSPSolveTranspose(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 921 ilink = ilink->next; 922 } 923 ierr = VecStrideScatterAll(jac->y,y,INSERT_VALUES);CHKERRQ(ierr); 924 } else { 925 ierr = VecSet(y,0.0);CHKERRQ(ierr); 926 while (ilink) { 927 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 928 ilink = ilink->next; 929 } 930 } 931 } else { 932 if (!jac->w1) { 933 ierr = VecDuplicate(x,&jac->w1);CHKERRQ(ierr); 934 ierr = VecDuplicate(x,&jac->w2);CHKERRQ(ierr); 935 } 936 ierr = VecSet(y,0.0);CHKERRQ(ierr); 937 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 938 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 939 while (ilink->next) { 940 ilink = ilink->next; 941 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 942 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 943 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 944 } 945 while (ilink->previous) { 946 ilink = ilink->previous; 947 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 948 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 949 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 950 } 951 } else { 952 while (ilink->next) { /* get to last entry in linked list */ 953 ilink = ilink->next; 954 } 955 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 956 while (ilink->previous) { 957 ilink = ilink->previous; 958 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 959 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 960 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 961 } 962 } 963 } 964 CHKMEMQ; 965 PetscFunctionReturn(0); 966 } 967 968 #undef __FUNCT__ 969 #define __FUNCT__ "PCReset_FieldSplit" 970 static PetscErrorCode PCReset_FieldSplit(PC pc) 971 { 972 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 973 PetscErrorCode ierr; 974 PC_FieldSplitLink ilink = jac->head,next; 975 976 PetscFunctionBegin; 977 while (ilink) { 978 ierr = KSPReset(ilink->ksp);CHKERRQ(ierr); 979 ierr = VecDestroy(&ilink->x);CHKERRQ(ierr); 980 ierr = VecDestroy(&ilink->y);CHKERRQ(ierr); 981 ierr = VecDestroy(&ilink->z);CHKERRQ(ierr); 982 ierr = VecScatterDestroy(&ilink->sctx);CHKERRQ(ierr); 983 ierr = ISDestroy(&ilink->is);CHKERRQ(ierr); 984 ierr = ISDestroy(&ilink->is_col);CHKERRQ(ierr); 985 next = ilink->next; 986 ilink = next; 987 } 988 ierr = PetscFree2(jac->x,jac->y);CHKERRQ(ierr); 989 if (jac->mat && jac->mat != jac->pmat) { 990 ierr = MatDestroyMatrices(jac->nsplits,&jac->mat);CHKERRQ(ierr); 991 } else if (jac->mat) { 992 jac->mat = NULL; 993 } 994 if (jac->pmat) {ierr = MatDestroyMatrices(jac->nsplits,&jac->pmat);CHKERRQ(ierr);} 995 if (jac->Afield) {ierr = MatDestroyMatrices(jac->nsplits,&jac->Afield);CHKERRQ(ierr);} 996 ierr = VecDestroy(&jac->w1);CHKERRQ(ierr); 997 ierr = VecDestroy(&jac->w2);CHKERRQ(ierr); 998 ierr = MatDestroy(&jac->schur);CHKERRQ(ierr); 999 ierr = MatDestroy(&jac->schur_user);CHKERRQ(ierr); 1000 ierr = KSPDestroy(&jac->kspschur);CHKERRQ(ierr); 1001 ierr = KSPDestroy(&jac->kspupper);CHKERRQ(ierr); 1002 ierr = MatDestroy(&jac->B);CHKERRQ(ierr); 1003 ierr = MatDestroy(&jac->C);CHKERRQ(ierr); 1004 jac->reset = PETSC_TRUE; 1005 PetscFunctionReturn(0); 1006 } 1007 1008 #undef __FUNCT__ 1009 #define __FUNCT__ "PCDestroy_FieldSplit" 1010 static PetscErrorCode PCDestroy_FieldSplit(PC pc) 1011 { 1012 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1013 PetscErrorCode ierr; 1014 PC_FieldSplitLink ilink = jac->head,next; 1015 1016 PetscFunctionBegin; 1017 ierr = PCReset_FieldSplit(pc);CHKERRQ(ierr); 1018 while (ilink) { 1019 ierr = KSPDestroy(&ilink->ksp);CHKERRQ(ierr); 1020 next = ilink->next; 1021 ierr = PetscFree(ilink->splitname);CHKERRQ(ierr); 1022 ierr = PetscFree(ilink->fields);CHKERRQ(ierr); 1023 ierr = PetscFree(ilink->fields_col);CHKERRQ(ierr); 1024 ierr = PetscFree(ilink);CHKERRQ(ierr); 1025 ilink = next; 1026 } 1027 ierr = PetscFree2(jac->x,jac->y);CHKERRQ(ierr); 1028 ierr = PetscFree(pc->data);CHKERRQ(ierr); 1029 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C","",NULL);CHKERRQ(ierr); 1030 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C","",NULL);CHKERRQ(ierr); 1031 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C","",NULL);CHKERRQ(ierr); 1032 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C","",NULL);CHKERRQ(ierr); 1033 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C","",NULL);CHKERRQ(ierr); 1034 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurPrecondition_C","",NULL);CHKERRQ(ierr); 1035 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C","",NULL);CHKERRQ(ierr); 1036 PetscFunctionReturn(0); 1037 } 1038 1039 #undef __FUNCT__ 1040 #define __FUNCT__ "PCSetFromOptions_FieldSplit" 1041 static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc) 1042 { 1043 PetscErrorCode ierr; 1044 PetscInt bs; 1045 PetscBool flg,stokes = PETSC_FALSE; 1046 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1047 PCCompositeType ctype; 1048 1049 PetscFunctionBegin; 1050 ierr = PetscOptionsHead("FieldSplit options");CHKERRQ(ierr); 1051 ierr = PetscOptionsBool("-pc_fieldsplit_dm_splits","Whether to use DMCreateFieldDecomposition() for splits","PCFieldSplitSetDMSplits",jac->dm_splits,&jac->dm_splits,NULL);CHKERRQ(ierr); 1052 ierr = PetscOptionsInt("-pc_fieldsplit_block_size","Blocksize that defines number of fields","PCFieldSplitSetBlockSize",jac->bs,&bs,&flg);CHKERRQ(ierr); 1053 if (flg) { 1054 ierr = PCFieldSplitSetBlockSize(pc,bs);CHKERRQ(ierr); 1055 } 1056 1057 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr); 1058 if (stokes) { 1059 ierr = PCFieldSplitSetType(pc,PC_COMPOSITE_SCHUR);CHKERRQ(ierr); 1060 jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_SELF; 1061 } 1062 1063 ierr = PetscOptionsEnum("-pc_fieldsplit_type","Type of composition","PCFieldSplitSetType",PCCompositeTypes,(PetscEnum)jac->type,(PetscEnum*)&ctype,&flg);CHKERRQ(ierr); 1064 if (flg) { 1065 ierr = PCFieldSplitSetType(pc,ctype);CHKERRQ(ierr); 1066 } 1067 /* Only setup fields once */ 1068 if ((jac->bs > 0) && (jac->nsplits == 0)) { 1069 /* only allow user to set fields from command line if bs is already known. 1070 otherwise user can set them in PCFieldSplitSetDefaults() */ 1071 ierr = PCFieldSplitSetRuntimeSplits_Private(pc);CHKERRQ(ierr); 1072 if (jac->splitdefined) {ierr = PetscInfo(pc,"Splits defined using the options database\n");CHKERRQ(ierr);} 1073 } 1074 if (jac->type == PC_COMPOSITE_SCHUR) { 1075 ierr = PetscOptionsGetEnum(((PetscObject)pc)->prefix,"-pc_fieldsplit_schur_factorization_type",PCFieldSplitSchurFactTypes,(PetscEnum*)&jac->schurfactorization,&flg);CHKERRQ(ierr); 1076 if (flg) {ierr = PetscInfo(pc,"Deprecated use of -pc_fieldsplit_schur_factorization_type\n");CHKERRQ(ierr);} 1077 ierr = PetscOptionsEnum("-pc_fieldsplit_schur_fact_type","Which off-diagonal parts of the block factorization to use","PCFieldSplitSetSchurFactType",PCFieldSplitSchurFactTypes,(PetscEnum)jac->schurfactorization,(PetscEnum*)&jac->schurfactorization,NULL);CHKERRQ(ierr); 1078 ierr = PetscOptionsEnum("-pc_fieldsplit_schur_precondition","How to build preconditioner for Schur complement","PCFieldSplitSchurPrecondition",PCFieldSplitSchurPreTypes,(PetscEnum)jac->schurpre,(PetscEnum*)&jac->schurpre,NULL);CHKERRQ(ierr); 1079 } 1080 ierr = PetscOptionsTail();CHKERRQ(ierr); 1081 PetscFunctionReturn(0); 1082 } 1083 1084 /*------------------------------------------------------------------------------------*/ 1085 1086 #undef __FUNCT__ 1087 #define __FUNCT__ "PCFieldSplitSetFields_FieldSplit" 1088 static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col) 1089 { 1090 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1091 PetscErrorCode ierr; 1092 PC_FieldSplitLink ilink,next = jac->head; 1093 char prefix[128]; 1094 PetscInt i; 1095 1096 PetscFunctionBegin; 1097 if (jac->splitdefined) { 1098 ierr = PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);CHKERRQ(ierr); 1099 PetscFunctionReturn(0); 1100 } 1101 for (i=0; i<n; i++) { 1102 if (fields[i] >= jac->bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Field %D requested but only %D exist",fields[i],jac->bs); 1103 if (fields[i] < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative field %D requested",fields[i]); 1104 } 1105 ierr = PetscNew(struct _PC_FieldSplitLink,&ilink);CHKERRQ(ierr); 1106 if (splitname) { 1107 ierr = PetscStrallocpy(splitname,&ilink->splitname);CHKERRQ(ierr); 1108 } else { 1109 ierr = PetscMalloc(3*sizeof(char),&ilink->splitname);CHKERRQ(ierr); 1110 ierr = PetscSNPrintf(ilink->splitname,2,"%s",jac->nsplits);CHKERRQ(ierr); 1111 } 1112 ierr = PetscMalloc(n*sizeof(PetscInt),&ilink->fields);CHKERRQ(ierr); 1113 ierr = PetscMemcpy(ilink->fields,fields,n*sizeof(PetscInt));CHKERRQ(ierr); 1114 ierr = PetscMalloc(n*sizeof(PetscInt),&ilink->fields_col);CHKERRQ(ierr); 1115 ierr = PetscMemcpy(ilink->fields_col,fields_col,n*sizeof(PetscInt));CHKERRQ(ierr); 1116 1117 ilink->nfields = n; 1118 ilink->next = NULL; 1119 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);CHKERRQ(ierr); 1120 ierr = PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);CHKERRQ(ierr); 1121 ierr = KSPSetType(ilink->ksp,KSPPREONLY);CHKERRQ(ierr); 1122 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);CHKERRQ(ierr); 1123 1124 ierr = PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);CHKERRQ(ierr); 1125 ierr = KSPSetOptionsPrefix(ilink->ksp,prefix);CHKERRQ(ierr); 1126 1127 if (!next) { 1128 jac->head = ilink; 1129 ilink->previous = NULL; 1130 } else { 1131 while (next->next) { 1132 next = next->next; 1133 } 1134 next->next = ilink; 1135 ilink->previous = next; 1136 } 1137 jac->nsplits++; 1138 PetscFunctionReturn(0); 1139 } 1140 1141 #undef __FUNCT__ 1142 #define __FUNCT__ "PCFieldSplitGetSubKSP_FieldSplit_Schur" 1143 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc,PetscInt *n,KSP **subksp) 1144 { 1145 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1146 PetscErrorCode ierr; 1147 1148 PetscFunctionBegin; 1149 ierr = PetscMalloc(jac->nsplits*sizeof(KSP),subksp);CHKERRQ(ierr); 1150 ierr = MatSchurComplementGetKSP(jac->schur,*subksp);CHKERRQ(ierr); 1151 1152 (*subksp)[1] = jac->kspschur; 1153 if (n) *n = jac->nsplits; 1154 PetscFunctionReturn(0); 1155 } 1156 1157 #undef __FUNCT__ 1158 #define __FUNCT__ "PCFieldSplitGetSubKSP_FieldSplit" 1159 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc,PetscInt *n,KSP **subksp) 1160 { 1161 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1162 PetscErrorCode ierr; 1163 PetscInt cnt = 0; 1164 PC_FieldSplitLink ilink = jac->head; 1165 1166 PetscFunctionBegin; 1167 ierr = PetscMalloc(jac->nsplits*sizeof(KSP),subksp);CHKERRQ(ierr); 1168 while (ilink) { 1169 (*subksp)[cnt++] = ilink->ksp; 1170 ilink = ilink->next; 1171 } 1172 if (cnt != jac->nsplits) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Corrupt PCFIELDSPLIT object: number of splits in linked list %D does not match number in object %D",cnt,jac->nsplits); 1173 if (n) *n = jac->nsplits; 1174 PetscFunctionReturn(0); 1175 } 1176 1177 #undef __FUNCT__ 1178 #define __FUNCT__ "PCFieldSplitSetIS_FieldSplit" 1179 static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc,const char splitname[],IS is) 1180 { 1181 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1182 PetscErrorCode ierr; 1183 PC_FieldSplitLink ilink, next = jac->head; 1184 char prefix[128]; 1185 1186 PetscFunctionBegin; 1187 if (jac->splitdefined) { 1188 ierr = PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);CHKERRQ(ierr); 1189 PetscFunctionReturn(0); 1190 } 1191 ierr = PetscNew(struct _PC_FieldSplitLink,&ilink);CHKERRQ(ierr); 1192 if (splitname) { 1193 ierr = PetscStrallocpy(splitname,&ilink->splitname);CHKERRQ(ierr); 1194 } else { 1195 ierr = PetscMalloc(8*sizeof(char),&ilink->splitname);CHKERRQ(ierr); 1196 ierr = PetscSNPrintf(ilink->splitname,7,"%D",jac->nsplits);CHKERRQ(ierr); 1197 } 1198 ierr = PetscObjectReference((PetscObject)is);CHKERRQ(ierr); 1199 ierr = ISDestroy(&ilink->is);CHKERRQ(ierr); 1200 ilink->is = is; 1201 ierr = PetscObjectReference((PetscObject)is);CHKERRQ(ierr); 1202 ierr = ISDestroy(&ilink->is_col);CHKERRQ(ierr); 1203 ilink->is_col = is; 1204 ilink->next = NULL; 1205 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);CHKERRQ(ierr); 1206 ierr = PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);CHKERRQ(ierr); 1207 ierr = KSPSetType(ilink->ksp,KSPPREONLY);CHKERRQ(ierr); 1208 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);CHKERRQ(ierr); 1209 1210 ierr = PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);CHKERRQ(ierr); 1211 ierr = KSPSetOptionsPrefix(ilink->ksp,prefix);CHKERRQ(ierr); 1212 1213 if (!next) { 1214 jac->head = ilink; 1215 ilink->previous = NULL; 1216 } else { 1217 while (next->next) { 1218 next = next->next; 1219 } 1220 next->next = ilink; 1221 ilink->previous = next; 1222 } 1223 jac->nsplits++; 1224 PetscFunctionReturn(0); 1225 } 1226 1227 #undef __FUNCT__ 1228 #define __FUNCT__ "PCFieldSplitSetFields" 1229 /*@ 1230 PCFieldSplitSetFields - Sets the fields for one particular split in the field split preconditioner 1231 1232 Logically Collective on PC 1233 1234 Input Parameters: 1235 + pc - the preconditioner context 1236 . splitname - name of this split, if NULL the number of the split is used 1237 . n - the number of fields in this split 1238 - fields - the fields in this split 1239 1240 Level: intermediate 1241 1242 Notes: Use PCFieldSplitSetIS() to set a completely general set of indices as a field. 1243 1244 The PCFieldSplitSetFields() is for defining fields as strided blocks. For example, if the block 1245 size is three then one can define a field as 0, or 1 or 2 or 0,1 or 0,2 or 1,2 which mean 1246 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x1x3x5x7.. x12x45x78x.... 1247 where the numbered entries indicate what is in the field. 1248 1249 This function is called once per split (it creates a new split each time). Solve options 1250 for this split will be available under the prefix -fieldsplit_SPLITNAME_. 1251 1252 Developer Note: This routine does not actually create the IS representing the split, that is delayed 1253 until PCSetUp_FieldSplit(), because information about the vector/matrix layouts may not be 1254 available when this routine is called. 1255 1256 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize(), PCFieldSplitSetIS() 1257 1258 @*/ 1259 PetscErrorCode PCFieldSplitSetFields(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col) 1260 { 1261 PetscErrorCode ierr; 1262 1263 PetscFunctionBegin; 1264 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1265 PetscValidCharPointer(splitname,2); 1266 if (n < 1) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Provided number of fields %D in split \"%s\" not positive",n,splitname); 1267 PetscValidIntPointer(fields,3); 1268 ierr = PetscTryMethod(pc,"PCFieldSplitSetFields_C",(PC,const char[],PetscInt,const PetscInt*,const PetscInt*),(pc,splitname,n,fields,fields_col));CHKERRQ(ierr); 1269 PetscFunctionReturn(0); 1270 } 1271 1272 #undef __FUNCT__ 1273 #define __FUNCT__ "PCFieldSplitSetIS" 1274 /*@ 1275 PCFieldSplitSetIS - Sets the exact elements for field 1276 1277 Logically Collective on PC 1278 1279 Input Parameters: 1280 + pc - the preconditioner context 1281 . splitname - name of this split, if NULL the number of the split is used 1282 - is - the index set that defines the vector elements in this field 1283 1284 1285 Notes: 1286 Use PCFieldSplitSetFields(), for fields defined by strided types. 1287 1288 This function is called once per split (it creates a new split each time). Solve options 1289 for this split will be available under the prefix -fieldsplit_SPLITNAME_. 1290 1291 Level: intermediate 1292 1293 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize() 1294 1295 @*/ 1296 PetscErrorCode PCFieldSplitSetIS(PC pc,const char splitname[],IS is) 1297 { 1298 PetscErrorCode ierr; 1299 1300 PetscFunctionBegin; 1301 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1302 if (splitname) PetscValidCharPointer(splitname,2); 1303 PetscValidHeaderSpecific(is,IS_CLASSID,3); 1304 ierr = PetscTryMethod(pc,"PCFieldSplitSetIS_C",(PC,const char[],IS),(pc,splitname,is));CHKERRQ(ierr); 1305 PetscFunctionReturn(0); 1306 } 1307 1308 #undef __FUNCT__ 1309 #define __FUNCT__ "PCFieldSplitGetIS" 1310 /*@ 1311 PCFieldSplitGetIS - Retrieves the elements for a field as an IS 1312 1313 Logically Collective on PC 1314 1315 Input Parameters: 1316 + pc - the preconditioner context 1317 - splitname - name of this split 1318 1319 Output Parameter: 1320 - is - the index set that defines the vector elements in this field, or NULL if the field is not found 1321 1322 Level: intermediate 1323 1324 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetIS() 1325 1326 @*/ 1327 PetscErrorCode PCFieldSplitGetIS(PC pc,const char splitname[],IS *is) 1328 { 1329 PetscErrorCode ierr; 1330 1331 PetscFunctionBegin; 1332 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1333 PetscValidCharPointer(splitname,2); 1334 PetscValidPointer(is,3); 1335 { 1336 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1337 PC_FieldSplitLink ilink = jac->head; 1338 PetscBool found; 1339 1340 *is = NULL; 1341 while (ilink) { 1342 ierr = PetscStrcmp(ilink->splitname, splitname, &found);CHKERRQ(ierr); 1343 if (found) { 1344 *is = ilink->is; 1345 break; 1346 } 1347 ilink = ilink->next; 1348 } 1349 } 1350 PetscFunctionReturn(0); 1351 } 1352 1353 #undef __FUNCT__ 1354 #define __FUNCT__ "PCFieldSplitSetBlockSize" 1355 /*@ 1356 PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the 1357 fieldsplit preconditioner. If not set the matrix block size is used. 1358 1359 Logically Collective on PC 1360 1361 Input Parameters: 1362 + pc - the preconditioner context 1363 - bs - the block size 1364 1365 Level: intermediate 1366 1367 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields() 1368 1369 @*/ 1370 PetscErrorCode PCFieldSplitSetBlockSize(PC pc,PetscInt bs) 1371 { 1372 PetscErrorCode ierr; 1373 1374 PetscFunctionBegin; 1375 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1376 PetscValidLogicalCollectiveInt(pc,bs,2); 1377 ierr = PetscTryMethod(pc,"PCFieldSplitSetBlockSize_C",(PC,PetscInt),(pc,bs));CHKERRQ(ierr); 1378 PetscFunctionReturn(0); 1379 } 1380 1381 #undef __FUNCT__ 1382 #define __FUNCT__ "PCFieldSplitGetSubKSP" 1383 /*@C 1384 PCFieldSplitGetSubKSP - Gets the KSP contexts for all splits 1385 1386 Collective on KSP 1387 1388 Input Parameter: 1389 . pc - the preconditioner context 1390 1391 Output Parameters: 1392 + n - the number of splits 1393 - pc - the array of KSP contexts 1394 1395 Note: 1396 After PCFieldSplitGetSubKSP() the array of KSPs IS to be freed by the user 1397 (not the KSP just the array that contains them). 1398 1399 You must call KSPSetUp() before calling PCFieldSplitGetSubKSP(). 1400 1401 Fortran Usage: You must pass in a KSP array that is large enough to contain all the local KSPs. 1402 You can call PCFieldSplitGetSubKSP(pc,n,NULL_OBJECT,ierr) to determine how large the 1403 KSP array must be. 1404 1405 1406 Level: advanced 1407 1408 .seealso: PCFIELDSPLIT 1409 @*/ 1410 PetscErrorCode PCFieldSplitGetSubKSP(PC pc,PetscInt *n,KSP *subksp[]) 1411 { 1412 PetscErrorCode ierr; 1413 1414 PetscFunctionBegin; 1415 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1416 if (n) PetscValidIntPointer(n,2); 1417 ierr = PetscUseMethod(pc,"PCFieldSplitGetSubKSP_C",(PC,PetscInt*,KSP **),(pc,n,subksp));CHKERRQ(ierr); 1418 PetscFunctionReturn(0); 1419 } 1420 1421 #undef __FUNCT__ 1422 #define __FUNCT__ "PCFieldSplitSchurPrecondition" 1423 /*@ 1424 PCFieldSplitSchurPrecondition - Indicates if the Schur complement is preconditioned by a preconditioner constructed by the 1425 A11 matrix. Otherwise no preconditioner is used. 1426 1427 Collective on PC 1428 1429 Input Parameters: 1430 + pc - the preconditioner context 1431 . ptype - which matrix to use for preconditioning the Schur complement, PC_FIELDSPLIT_SCHUR_PRE_A11 (diag) is default 1432 - userpre - matrix to use for preconditioning, or NULL 1433 1434 Options Database: 1435 . -pc_fieldsplit_schur_precondition <self,user,a11> default is a11 1436 1437 Notes: 1438 $ If ptype is 1439 $ user then the preconditioner for the Schur complement is generated by the provided matrix (pre argument 1440 $ to this function). 1441 $ a11 then the preconditioner for the Schur complement is generated by the block diagonal part of the original 1442 $ matrix associated with the Schur complement (i.e. A11) 1443 $ self the preconditioner for the Schur complement is generated from the Schur complement matrix itself: 1444 $ The only preconditioner that currently works directly with the Schur complement matrix object is the PCLSC 1445 $ preconditioner 1446 1447 When solving a saddle point problem, where the A11 block is identically zero, using a11 as the ptype only makes sense 1448 with the additional option -fieldsplit_1_pc_type none. Usually for saddle point problems one would use a ptype of self and 1449 -fieldsplit_1_pc_type lsc which uses the least squares commutator compute a preconditioner for the Schur complement. 1450 1451 Developer Notes: This is a terrible name, gives no good indication of what the function does and should also have Set in 1452 the name since it sets a proceedure to use. 1453 1454 Level: intermediate 1455 1456 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType, PCLSC 1457 1458 @*/ 1459 PetscErrorCode PCFieldSplitSchurPrecondition(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) 1460 { 1461 PetscErrorCode ierr; 1462 1463 PetscFunctionBegin; 1464 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1465 ierr = PetscTryMethod(pc,"PCFieldSplitSchurPrecondition_C",(PC,PCFieldSplitSchurPreType,Mat),(pc,ptype,pre));CHKERRQ(ierr); 1466 PetscFunctionReturn(0); 1467 } 1468 1469 #undef __FUNCT__ 1470 #define __FUNCT__ "PCFieldSplitSchurPrecondition_FieldSplit" 1471 static PetscErrorCode PCFieldSplitSchurPrecondition_FieldSplit(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) 1472 { 1473 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1474 PetscErrorCode ierr; 1475 1476 PetscFunctionBegin; 1477 jac->schurpre = ptype; 1478 if (pre) { 1479 ierr = MatDestroy(&jac->schur_user);CHKERRQ(ierr); 1480 jac->schur_user = pre; 1481 ierr = PetscObjectReference((PetscObject)jac->schur_user);CHKERRQ(ierr); 1482 } 1483 PetscFunctionReturn(0); 1484 } 1485 1486 #undef __FUNCT__ 1487 #define __FUNCT__ "PCFieldSplitSetSchurFactType" 1488 /*@ 1489 PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain 1490 1491 Collective on PC 1492 1493 Input Parameters: 1494 + pc - the preconditioner context 1495 - ftype - which blocks of factorization to retain, PC_FIELDSPLIT_SCHUR_FACT_FULL is default 1496 1497 Options Database: 1498 . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> default is full 1499 1500 1501 Level: intermediate 1502 1503 Notes: 1504 The FULL factorization is 1505 1506 $ (A B) = (1 0) (A 0) (1 Ainv*B) 1507 $ (C D) (C*Ainv 1) (0 S) (0 1 ) 1508 1509 where S = D - C*Ainv*B. In practice, the full factorization is applied via block triangular solves with the grouping L*(D*U). UPPER uses D*U, LOWER uses L*D, 1510 and DIAG is the diagonal part with the sign of S flipped (because this makes the preconditioner positive definite for many formulations, thus allowing the use of KSPMINRES). 1511 1512 If applied exactly, FULL factorization is a direct solver. The preconditioned operator with LOWER or UPPER has all eigenvalues equal to 1 and minimal polynomial 1513 of degree 2, so KSPGMRES converges in 2 iterations. If the iteration count is very low, consider using KSPFGMRES or KSPGCR which can use one less preconditioner 1514 application in this case. Note that the preconditioned operator may be highly non-normal, so such fast convergence may not be observed in practice. With DIAG, 1515 the preconditioned operator has three distinct nonzero eigenvalues and minimal polynomial of degree at most 4, so KSPGMRES converges in at most 4 iterations. 1516 1517 For symmetric problems in which A is positive definite and S is negative definite, DIAG can be used with KSPMINRES. Note that a flexible method like KSPFGMRES 1518 or KSPGCR must be used if the fieldsplit preconditioner is nonlinear (e.g. a few iterations of a Krylov method is used inside a split). 1519 1520 References: 1521 Murphy, Golub, and Wathen, A note on preconditioning indefinite linear systems, SIAM J. Sci. Comput., 21 (2000) pp. 1969-1972. 1522 1523 Ipsen, A note on preconditioning nonsymmetric matrices, SIAM J. Sci. Comput., 23 (2001), pp. 1050-1051. 1524 1525 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType 1526 @*/ 1527 PetscErrorCode PCFieldSplitSetSchurFactType(PC pc,PCFieldSplitSchurFactType ftype) 1528 { 1529 PetscErrorCode ierr; 1530 1531 PetscFunctionBegin; 1532 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1533 ierr = PetscTryMethod(pc,"PCFieldSplitSetSchurFactType_C",(PC,PCFieldSplitSchurFactType),(pc,ftype));CHKERRQ(ierr); 1534 PetscFunctionReturn(0); 1535 } 1536 1537 #undef __FUNCT__ 1538 #define __FUNCT__ "PCFieldSplitSetSchurFactType_FieldSplit" 1539 static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc,PCFieldSplitSchurFactType ftype) 1540 { 1541 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1542 1543 PetscFunctionBegin; 1544 jac->schurfactorization = ftype; 1545 PetscFunctionReturn(0); 1546 } 1547 1548 #undef __FUNCT__ 1549 #define __FUNCT__ "PCFieldSplitGetSchurBlocks" 1550 /*@C 1551 PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement 1552 1553 Collective on KSP 1554 1555 Input Parameter: 1556 . pc - the preconditioner context 1557 1558 Output Parameters: 1559 + A00 - the (0,0) block 1560 . A01 - the (0,1) block 1561 . A10 - the (1,0) block 1562 - A11 - the (1,1) block 1563 1564 Level: advanced 1565 1566 .seealso: PCFIELDSPLIT 1567 @*/ 1568 PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc,Mat *A00,Mat *A01,Mat *A10, Mat *A11) 1569 { 1570 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1571 1572 PetscFunctionBegin; 1573 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1574 if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach."); 1575 if (A00) *A00 = jac->pmat[0]; 1576 if (A01) *A01 = jac->B; 1577 if (A10) *A10 = jac->C; 1578 if (A11) *A11 = jac->pmat[1]; 1579 PetscFunctionReturn(0); 1580 } 1581 1582 #undef __FUNCT__ 1583 #define __FUNCT__ "PCFieldSplitSetType_FieldSplit" 1584 static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc,PCCompositeType type) 1585 { 1586 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1587 PetscErrorCode ierr; 1588 1589 PetscFunctionBegin; 1590 jac->type = type; 1591 if (type == PC_COMPOSITE_SCHUR) { 1592 pc->ops->apply = PCApply_FieldSplit_Schur; 1593 pc->ops->view = PCView_FieldSplit_Schur; 1594 1595 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C","PCFieldSplitGetSubKSP_FieldSplit_Schur",PCFieldSplitGetSubKSP_FieldSplit_Schur);CHKERRQ(ierr); 1596 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurPrecondition_C","PCFieldSplitSchurPrecondition_FieldSplit",PCFieldSplitSchurPrecondition_FieldSplit);CHKERRQ(ierr); 1597 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C","PCFieldSplitSetSchurFactType_FieldSplit",PCFieldSplitSetSchurFactType_FieldSplit);CHKERRQ(ierr); 1598 1599 } else { 1600 pc->ops->apply = PCApply_FieldSplit; 1601 pc->ops->view = PCView_FieldSplit; 1602 1603 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C","PCFieldSplitGetSubKSP_FieldSplit",PCFieldSplitGetSubKSP_FieldSplit);CHKERRQ(ierr); 1604 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurPrecondition_C","",0);CHKERRQ(ierr); 1605 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C","",0);CHKERRQ(ierr); 1606 } 1607 PetscFunctionReturn(0); 1608 } 1609 1610 #undef __FUNCT__ 1611 #define __FUNCT__ "PCFieldSplitSetBlockSize_FieldSplit" 1612 static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc,PetscInt bs) 1613 { 1614 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1615 1616 PetscFunctionBegin; 1617 if (bs < 1) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Blocksize must be positive, you gave %D",bs); 1618 if (jac->bs > 0 && jac->bs != bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Cannot change fieldsplit blocksize from %D to %D after it has been set",jac->bs,bs); 1619 jac->bs = bs; 1620 PetscFunctionReturn(0); 1621 } 1622 1623 #undef __FUNCT__ 1624 #define __FUNCT__ "PCFieldSplitSetType" 1625 /*@ 1626 PCFieldSplitSetType - Sets the type of fieldsplit preconditioner. 1627 1628 Collective on PC 1629 1630 Input Parameter: 1631 . pc - the preconditioner context 1632 . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR 1633 1634 Options Database Key: 1635 . -pc_fieldsplit_type <type: one of multiplicative, additive, symmetric_multiplicative, special, schur> - Sets fieldsplit preconditioner type 1636 1637 Level: Intermediate 1638 1639 .keywords: PC, set, type, composite preconditioner, additive, multiplicative 1640 1641 .seealso: PCCompositeSetType() 1642 1643 @*/ 1644 PetscErrorCode PCFieldSplitSetType(PC pc,PCCompositeType type) 1645 { 1646 PetscErrorCode ierr; 1647 1648 PetscFunctionBegin; 1649 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1650 ierr = PetscTryMethod(pc,"PCFieldSplitSetType_C",(PC,PCCompositeType),(pc,type));CHKERRQ(ierr); 1651 PetscFunctionReturn(0); 1652 } 1653 1654 #undef __FUNCT__ 1655 #define __FUNCT__ "PCFieldSplitGetType" 1656 /*@ 1657 PCFieldSplitGetType - Gets the type of fieldsplit preconditioner. 1658 1659 Not collective 1660 1661 Input Parameter: 1662 . pc - the preconditioner context 1663 1664 Output Parameter: 1665 . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR 1666 1667 Level: Intermediate 1668 1669 .keywords: PC, set, type, composite preconditioner, additive, multiplicative 1670 .seealso: PCCompositeSetType() 1671 @*/ 1672 PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type) 1673 { 1674 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1675 1676 PetscFunctionBegin; 1677 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1678 PetscValidIntPointer(type,2); 1679 *type = jac->type; 1680 PetscFunctionReturn(0); 1681 } 1682 1683 #undef __FUNCT__ 1684 #define __FUNCT__ "PCFieldSplitSetDMSplits" 1685 /*@ 1686 PCFieldSplitSetDMSplits - Flags whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible. 1687 1688 Logically Collective 1689 1690 Input Parameters: 1691 + pc - the preconditioner context 1692 - flg - boolean indicating whether to use field splits defined by the DM 1693 1694 Options Database Key: 1695 . -pc_fieldsplit_dm_splits 1696 1697 Level: Intermediate 1698 1699 .keywords: PC, DM, composite preconditioner, additive, multiplicative 1700 1701 .seealso: PCFieldSplitGetDMSplits() 1702 1703 @*/ 1704 PetscErrorCode PCFieldSplitSetDMSplits(PC pc,PetscBool flg) 1705 { 1706 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1707 PetscBool isfs; 1708 PetscErrorCode ierr; 1709 1710 PetscFunctionBegin; 1711 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1712 PetscValidLogicalCollectiveBool(pc,flg,2); 1713 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1714 if (isfs) { 1715 jac->dm_splits = flg; 1716 } 1717 PetscFunctionReturn(0); 1718 } 1719 1720 1721 #undef __FUNCT__ 1722 #define __FUNCT__ "PCFieldSplitGetDMSplits" 1723 /*@ 1724 PCFieldSplitGetDMSplits - Returns flag indicating whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible. 1725 1726 Logically Collective 1727 1728 Input Parameter: 1729 . pc - the preconditioner context 1730 1731 Output Parameter: 1732 . flg - boolean indicating whether to use field splits defined by the DM 1733 1734 Level: Intermediate 1735 1736 .keywords: PC, DM, composite preconditioner, additive, multiplicative 1737 1738 .seealso: PCFieldSplitSetDMSplits() 1739 1740 @*/ 1741 PetscErrorCode PCFieldSplitGetDMSplits(PC pc,PetscBool* flg) 1742 { 1743 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1744 PetscBool isfs; 1745 PetscErrorCode ierr; 1746 1747 PetscFunctionBegin; 1748 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1749 PetscValidPointer(flg,2); 1750 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1751 if (isfs) { 1752 if(flg) *flg = jac->dm_splits; 1753 } 1754 PetscFunctionReturn(0); 1755 } 1756 1757 /* -------------------------------------------------------------------------------------*/ 1758 /*MC 1759 PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual 1760 fields or groups of fields. See the users manual section "Solving Block Matrices" for more details. 1761 1762 To set options on the solvers for each block append -fieldsplit_ to all the PC 1763 options database keys. For example, -fieldsplit_pc_type ilu -fieldsplit_pc_factor_levels 1 1764 1765 To set the options on the solvers separate for each block call PCFieldSplitGetSubKSP() 1766 and set the options directly on the resulting KSP object 1767 1768 Level: intermediate 1769 1770 Options Database Keys: 1771 + -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the %d'th split 1772 . -pc_fieldsplit_default - automatically add any fields to additional splits that have not 1773 been supplied explicitly by -pc_fieldsplit_%d_fields 1774 . -pc_fieldsplit_block_size <bs> - size of block that defines fields (i.e. there are bs fields) 1775 . -pc_fieldsplit_type <additive,multiplicative,symmetric_multiplicative,schur> - type of relaxation or factorization splitting 1776 . -pc_fieldsplit_schur_precondition <self,user,a11> - default is a11 1777 . -pc_fieldsplit_detect_saddle_point - automatically finds rows with zero or negative diagonal and uses Schur complement with no preconditioner as the solver 1778 1779 - Options prefix for inner solvers when using Schur complement preconditioner are -fieldsplit_0_ and -fieldsplit_1_ 1780 for all other solvers they are -fieldsplit_%d_ for the dth field, use -fieldsplit_ for all fields 1781 1782 Notes: 1783 Use PCFieldSplitSetFields() to set fields defined by "strided" entries and PCFieldSplitSetIS() 1784 to define a field by an arbitrary collection of entries. 1785 1786 If no fields are set the default is used. The fields are defined by entries strided by bs, 1787 beginning at 0 then 1, etc to bs-1. The block size can be set with PCFieldSplitSetBlockSize(), 1788 if this is not called the block size defaults to the blocksize of the second matrix passed 1789 to KSPSetOperators()/PCSetOperators(). 1790 1791 $ For the Schur complement preconditioner if J = ( A00 A01 ) 1792 $ ( A10 A11 ) 1793 $ the preconditioner using full factorization is 1794 $ ( I -A10 ksp(A00) ) ( inv(A00) 0 ) ( I 0 ) 1795 $ ( 0 I ) ( 0 ksp(S) ) ( -A10 ksp(A00) I ) 1796 where the action of inv(A00) is applied using the KSP solver with prefix -fieldsplit_0_. The action of 1797 ksp(S) is computed using the KSP solver with prefix -fieldsplit_splitname_ (where splitname was given 1798 in providing the SECOND split or 1 if not give). For PCFieldSplitGetKSP() when field number is 0, 1799 it returns the KSP associated with -fieldsplit_0_ while field number 1 gives -fieldsplit_1_ KSP. By default 1800 A11 is used to construct a preconditioner for S, use PCFieldSplitSchurPrecondition() to turn on or off this 1801 option. You can use the preconditioner PCLSC to precondition the Schur complement with -fieldsplit_1_pc_type lsc. The 1802 factorization type is set using -pc_fieldsplit_schur_fact_type <diag, lower, upper, full>. The full is shown above, 1803 diag gives 1804 $ ( inv(A00) 0 ) 1805 $ ( 0 -ksp(S) ) 1806 note that slightly counter intuitively there is a negative in front of the ksp(S) so that the preconditioner is positive definite. The lower factorization is the inverse of 1807 $ ( A00 0 ) 1808 $ ( A10 S ) 1809 where the inverses of A00 and S are applied using KSPs. The upper factorization is the inverse of 1810 $ ( A00 A01 ) 1811 $ ( 0 S ) 1812 where again the inverses of A00 and S are applied using KSPs. 1813 1814 If only one set of indices (one IS) is provided with PCFieldSplitSetIS() then the complement of that IS 1815 is used automatically for a second block. 1816 1817 The fieldsplit preconditioner cannot currently be used with the BAIJ or SBAIJ data formats if the blocksize is larger than 1. 1818 Generally it should be used with the AIJ format. 1819 1820 The forms of these preconditioners are closely related if not identical to forms derived as "Distributive Iterations", see, 1821 for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling. Note that one can also use PCFIELDSPLIT 1822 inside a smoother resulting in "Distributive Smoothers". 1823 1824 Concepts: physics based preconditioners, block preconditioners 1825 1826 .seealso: PCCreate(), PCSetType(), PCType (for list of available types), PC, Block_Preconditioners, PCLSC, 1827 PCFieldSplitGetSubKSP(), PCFieldSplitSetFields(), PCFieldSplitSetType(), PCFieldSplitSetIS(), PCFieldSplitSchurPrecondition() 1828 M*/ 1829 1830 #undef __FUNCT__ 1831 #define __FUNCT__ "PCCreate_FieldSplit" 1832 PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc) 1833 { 1834 PetscErrorCode ierr; 1835 PC_FieldSplit *jac; 1836 1837 PetscFunctionBegin; 1838 ierr = PetscNewLog(pc,PC_FieldSplit,&jac);CHKERRQ(ierr); 1839 1840 jac->bs = -1; 1841 jac->nsplits = 0; 1842 jac->type = PC_COMPOSITE_MULTIPLICATIVE; 1843 jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */ 1844 jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL; 1845 jac->dm_splits = PETSC_TRUE; 1846 1847 pc->data = (void*)jac; 1848 1849 pc->ops->apply = PCApply_FieldSplit; 1850 pc->ops->applytranspose = PCApplyTranspose_FieldSplit; 1851 pc->ops->setup = PCSetUp_FieldSplit; 1852 pc->ops->reset = PCReset_FieldSplit; 1853 pc->ops->destroy = PCDestroy_FieldSplit; 1854 pc->ops->setfromoptions = PCSetFromOptions_FieldSplit; 1855 pc->ops->view = PCView_FieldSplit; 1856 pc->ops->applyrichardson = 0; 1857 1858 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C","PCFieldSplitGetSubKSP_FieldSplit",PCFieldSplitGetSubKSP_FieldSplit);CHKERRQ(ierr); 1859 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C","PCFieldSplitSetFields_FieldSplit",PCFieldSplitSetFields_FieldSplit);CHKERRQ(ierr); 1860 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C","PCFieldSplitSetIS_FieldSplit",PCFieldSplitSetIS_FieldSplit);CHKERRQ(ierr); 1861 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C","PCFieldSplitSetType_FieldSplit",PCFieldSplitSetType_FieldSplit);CHKERRQ(ierr); 1862 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C","PCFieldSplitSetBlockSize_FieldSplit",PCFieldSplitSetBlockSize_FieldSplit);CHKERRQ(ierr); 1863 PetscFunctionReturn(0); 1864 } 1865 1866 1867 1868