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 if (jac->type == PC_COMPOSITE_ADDITIVE) { 837 if (jac->defaultsplit) { 838 ierr = VecGetBlockSize(x,&bs);CHKERRQ(ierr); 839 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); 840 ierr = VecGetBlockSize(y,&bs);CHKERRQ(ierr); 841 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); 842 ierr = VecStrideGatherAll(x,jac->x,INSERT_VALUES);CHKERRQ(ierr); 843 while (ilink) { 844 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 845 ilink = ilink->next; 846 } 847 ierr = VecStrideScatterAll(jac->y,y,INSERT_VALUES);CHKERRQ(ierr); 848 } else { 849 ierr = VecSet(y,0.0);CHKERRQ(ierr); 850 while (ilink) { 851 ierr = FieldSplitSplitSolveAdd(ilink,x,y);CHKERRQ(ierr); 852 ilink = ilink->next; 853 } 854 } 855 } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 856 if (!jac->w1) { 857 ierr = VecDuplicate(x,&jac->w1);CHKERRQ(ierr); 858 ierr = VecDuplicate(x,&jac->w2);CHKERRQ(ierr); 859 } 860 ierr = VecSet(y,0.0);CHKERRQ(ierr); 861 ierr = FieldSplitSplitSolveAdd(ilink,x,y);CHKERRQ(ierr); 862 cnt = 1; 863 while (ilink->next) { 864 ilink = ilink->next; 865 /* compute the residual only over the part of the vector needed */ 866 ierr = MatMult(jac->Afield[cnt++],y,ilink->x);CHKERRQ(ierr); 867 ierr = VecScale(ilink->x,-1.0);CHKERRQ(ierr); 868 ierr = VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 869 ierr = VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 870 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 871 ierr = VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 872 ierr = VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 873 } 874 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 875 cnt -= 2; 876 while (ilink->previous) { 877 ilink = ilink->previous; 878 /* compute the residual only over the part of the vector needed */ 879 ierr = MatMult(jac->Afield[cnt--],y,ilink->x);CHKERRQ(ierr); 880 ierr = VecScale(ilink->x,-1.0);CHKERRQ(ierr); 881 ierr = VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 882 ierr = VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 883 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 884 ierr = VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 885 ierr = VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 886 } 887 } 888 } else SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Unsupported or unknown composition",(int) jac->type); 889 PetscFunctionReturn(0); 890 } 891 892 #define FieldSplitSplitSolveAddTranspose(ilink,xx,yy) \ 893 (VecScatterBegin(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \ 894 VecScatterEnd(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \ 895 KSPSolveTranspose(ilink->ksp,ilink->y,ilink->x) || \ 896 VecScatterBegin(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE) || \ 897 VecScatterEnd(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE)) 898 899 #undef __FUNCT__ 900 #define __FUNCT__ "PCApplyTranspose_FieldSplit" 901 static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc,Vec x,Vec y) 902 { 903 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 904 PetscErrorCode ierr; 905 PC_FieldSplitLink ilink = jac->head; 906 PetscInt bs; 907 908 PetscFunctionBegin; 909 if (jac->type == PC_COMPOSITE_ADDITIVE) { 910 if (jac->defaultsplit) { 911 ierr = VecGetBlockSize(x,&bs);CHKERRQ(ierr); 912 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); 913 ierr = VecGetBlockSize(y,&bs);CHKERRQ(ierr); 914 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); 915 ierr = VecStrideGatherAll(x,jac->x,INSERT_VALUES);CHKERRQ(ierr); 916 while (ilink) { 917 ierr = KSPSolveTranspose(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 918 ilink = ilink->next; 919 } 920 ierr = VecStrideScatterAll(jac->y,y,INSERT_VALUES);CHKERRQ(ierr); 921 } else { 922 ierr = VecSet(y,0.0);CHKERRQ(ierr); 923 while (ilink) { 924 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 925 ilink = ilink->next; 926 } 927 } 928 } else { 929 if (!jac->w1) { 930 ierr = VecDuplicate(x,&jac->w1);CHKERRQ(ierr); 931 ierr = VecDuplicate(x,&jac->w2);CHKERRQ(ierr); 932 } 933 ierr = VecSet(y,0.0);CHKERRQ(ierr); 934 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 935 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 936 while (ilink->next) { 937 ilink = ilink->next; 938 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 939 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 940 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 941 } 942 while (ilink->previous) { 943 ilink = ilink->previous; 944 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 945 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 946 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 947 } 948 } else { 949 while (ilink->next) { /* get to last entry in linked list */ 950 ilink = ilink->next; 951 } 952 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 953 while (ilink->previous) { 954 ilink = ilink->previous; 955 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 956 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 957 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 958 } 959 } 960 } 961 PetscFunctionReturn(0); 962 } 963 964 #undef __FUNCT__ 965 #define __FUNCT__ "PCReset_FieldSplit" 966 static PetscErrorCode PCReset_FieldSplit(PC pc) 967 { 968 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 969 PetscErrorCode ierr; 970 PC_FieldSplitLink ilink = jac->head,next; 971 972 PetscFunctionBegin; 973 while (ilink) { 974 ierr = KSPReset(ilink->ksp);CHKERRQ(ierr); 975 ierr = VecDestroy(&ilink->x);CHKERRQ(ierr); 976 ierr = VecDestroy(&ilink->y);CHKERRQ(ierr); 977 ierr = VecDestroy(&ilink->z);CHKERRQ(ierr); 978 ierr = VecScatterDestroy(&ilink->sctx);CHKERRQ(ierr); 979 ierr = ISDestroy(&ilink->is);CHKERRQ(ierr); 980 ierr = ISDestroy(&ilink->is_col);CHKERRQ(ierr); 981 next = ilink->next; 982 ilink = next; 983 } 984 ierr = PetscFree2(jac->x,jac->y);CHKERRQ(ierr); 985 if (jac->mat && jac->mat != jac->pmat) { 986 ierr = MatDestroyMatrices(jac->nsplits,&jac->mat);CHKERRQ(ierr); 987 } else if (jac->mat) { 988 jac->mat = NULL; 989 } 990 if (jac->pmat) {ierr = MatDestroyMatrices(jac->nsplits,&jac->pmat);CHKERRQ(ierr);} 991 if (jac->Afield) {ierr = MatDestroyMatrices(jac->nsplits,&jac->Afield);CHKERRQ(ierr);} 992 ierr = VecDestroy(&jac->w1);CHKERRQ(ierr); 993 ierr = VecDestroy(&jac->w2);CHKERRQ(ierr); 994 ierr = MatDestroy(&jac->schur);CHKERRQ(ierr); 995 ierr = MatDestroy(&jac->schur_user);CHKERRQ(ierr); 996 ierr = KSPDestroy(&jac->kspschur);CHKERRQ(ierr); 997 ierr = KSPDestroy(&jac->kspupper);CHKERRQ(ierr); 998 ierr = MatDestroy(&jac->B);CHKERRQ(ierr); 999 ierr = MatDestroy(&jac->C);CHKERRQ(ierr); 1000 jac->reset = PETSC_TRUE; 1001 PetscFunctionReturn(0); 1002 } 1003 1004 #undef __FUNCT__ 1005 #define __FUNCT__ "PCDestroy_FieldSplit" 1006 static PetscErrorCode PCDestroy_FieldSplit(PC pc) 1007 { 1008 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1009 PetscErrorCode ierr; 1010 PC_FieldSplitLink ilink = jac->head,next; 1011 1012 PetscFunctionBegin; 1013 ierr = PCReset_FieldSplit(pc);CHKERRQ(ierr); 1014 while (ilink) { 1015 ierr = KSPDestroy(&ilink->ksp);CHKERRQ(ierr); 1016 next = ilink->next; 1017 ierr = PetscFree(ilink->splitname);CHKERRQ(ierr); 1018 ierr = PetscFree(ilink->fields);CHKERRQ(ierr); 1019 ierr = PetscFree(ilink->fields_col);CHKERRQ(ierr); 1020 ierr = PetscFree(ilink);CHKERRQ(ierr); 1021 ilink = next; 1022 } 1023 ierr = PetscFree2(jac->x,jac->y);CHKERRQ(ierr); 1024 ierr = PetscFree(pc->data);CHKERRQ(ierr); 1025 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",NULL);CHKERRQ(ierr); 1026 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C",NULL);CHKERRQ(ierr); 1027 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C",NULL);CHKERRQ(ierr); 1028 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C",NULL);CHKERRQ(ierr); 1029 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C",NULL);CHKERRQ(ierr); 1030 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurPrecondition_C",NULL);CHKERRQ(ierr); 1031 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",NULL);CHKERRQ(ierr); 1032 PetscFunctionReturn(0); 1033 } 1034 1035 #undef __FUNCT__ 1036 #define __FUNCT__ "PCSetFromOptions_FieldSplit" 1037 static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc) 1038 { 1039 PetscErrorCode ierr; 1040 PetscInt bs; 1041 PetscBool flg,stokes = PETSC_FALSE; 1042 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1043 PCCompositeType ctype; 1044 1045 PetscFunctionBegin; 1046 ierr = PetscOptionsHead("FieldSplit options");CHKERRQ(ierr); 1047 ierr = PetscOptionsBool("-pc_fieldsplit_dm_splits","Whether to use DMCreateFieldDecomposition() for splits","PCFieldSplitSetDMSplits",jac->dm_splits,&jac->dm_splits,NULL);CHKERRQ(ierr); 1048 ierr = PetscOptionsInt("-pc_fieldsplit_block_size","Blocksize that defines number of fields","PCFieldSplitSetBlockSize",jac->bs,&bs,&flg);CHKERRQ(ierr); 1049 if (flg) { 1050 ierr = PCFieldSplitSetBlockSize(pc,bs);CHKERRQ(ierr); 1051 } 1052 1053 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr); 1054 if (stokes) { 1055 ierr = PCFieldSplitSetType(pc,PC_COMPOSITE_SCHUR);CHKERRQ(ierr); 1056 jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_SELF; 1057 } 1058 1059 ierr = PetscOptionsEnum("-pc_fieldsplit_type","Type of composition","PCFieldSplitSetType",PCCompositeTypes,(PetscEnum)jac->type,(PetscEnum*)&ctype,&flg);CHKERRQ(ierr); 1060 if (flg) { 1061 ierr = PCFieldSplitSetType(pc,ctype);CHKERRQ(ierr); 1062 } 1063 /* Only setup fields once */ 1064 if ((jac->bs > 0) && (jac->nsplits == 0)) { 1065 /* only allow user to set fields from command line if bs is already known. 1066 otherwise user can set them in PCFieldSplitSetDefaults() */ 1067 ierr = PCFieldSplitSetRuntimeSplits_Private(pc);CHKERRQ(ierr); 1068 if (jac->splitdefined) {ierr = PetscInfo(pc,"Splits defined using the options database\n");CHKERRQ(ierr);} 1069 } 1070 if (jac->type == PC_COMPOSITE_SCHUR) { 1071 ierr = PetscOptionsGetEnum(((PetscObject)pc)->prefix,"-pc_fieldsplit_schur_factorization_type",PCFieldSplitSchurFactTypes,(PetscEnum*)&jac->schurfactorization,&flg);CHKERRQ(ierr); 1072 if (flg) {ierr = PetscInfo(pc,"Deprecated use of -pc_fieldsplit_schur_factorization_type\n");CHKERRQ(ierr);} 1073 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); 1074 ierr = PetscOptionsEnum("-pc_fieldsplit_schur_precondition","How to build preconditioner for Schur complement","PCFieldSplitSchurPrecondition",PCFieldSplitSchurPreTypes,(PetscEnum)jac->schurpre,(PetscEnum*)&jac->schurpre,NULL);CHKERRQ(ierr); 1075 } 1076 ierr = PetscOptionsTail();CHKERRQ(ierr); 1077 PetscFunctionReturn(0); 1078 } 1079 1080 /*------------------------------------------------------------------------------------*/ 1081 1082 #undef __FUNCT__ 1083 #define __FUNCT__ "PCFieldSplitSetFields_FieldSplit" 1084 static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col) 1085 { 1086 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1087 PetscErrorCode ierr; 1088 PC_FieldSplitLink ilink,next = jac->head; 1089 char prefix[128]; 1090 PetscInt i; 1091 1092 PetscFunctionBegin; 1093 if (jac->splitdefined) { 1094 ierr = PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);CHKERRQ(ierr); 1095 PetscFunctionReturn(0); 1096 } 1097 for (i=0; i<n; i++) { 1098 if (fields[i] >= jac->bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Field %D requested but only %D exist",fields[i],jac->bs); 1099 if (fields[i] < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative field %D requested",fields[i]); 1100 } 1101 ierr = PetscNew(struct _PC_FieldSplitLink,&ilink);CHKERRQ(ierr); 1102 if (splitname) { 1103 ierr = PetscStrallocpy(splitname,&ilink->splitname);CHKERRQ(ierr); 1104 } else { 1105 ierr = PetscMalloc(3*sizeof(char),&ilink->splitname);CHKERRQ(ierr); 1106 ierr = PetscSNPrintf(ilink->splitname,2,"%s",jac->nsplits);CHKERRQ(ierr); 1107 } 1108 ierr = PetscMalloc(n*sizeof(PetscInt),&ilink->fields);CHKERRQ(ierr); 1109 ierr = PetscMemcpy(ilink->fields,fields,n*sizeof(PetscInt));CHKERRQ(ierr); 1110 ierr = PetscMalloc(n*sizeof(PetscInt),&ilink->fields_col);CHKERRQ(ierr); 1111 ierr = PetscMemcpy(ilink->fields_col,fields_col,n*sizeof(PetscInt));CHKERRQ(ierr); 1112 1113 ilink->nfields = n; 1114 ilink->next = NULL; 1115 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);CHKERRQ(ierr); 1116 ierr = PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);CHKERRQ(ierr); 1117 ierr = KSPSetType(ilink->ksp,KSPPREONLY);CHKERRQ(ierr); 1118 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);CHKERRQ(ierr); 1119 1120 ierr = PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);CHKERRQ(ierr); 1121 ierr = KSPSetOptionsPrefix(ilink->ksp,prefix);CHKERRQ(ierr); 1122 1123 if (!next) { 1124 jac->head = ilink; 1125 ilink->previous = NULL; 1126 } else { 1127 while (next->next) { 1128 next = next->next; 1129 } 1130 next->next = ilink; 1131 ilink->previous = next; 1132 } 1133 jac->nsplits++; 1134 PetscFunctionReturn(0); 1135 } 1136 1137 #undef __FUNCT__ 1138 #define __FUNCT__ "PCFieldSplitGetSubKSP_FieldSplit_Schur" 1139 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc,PetscInt *n,KSP **subksp) 1140 { 1141 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1142 PetscErrorCode ierr; 1143 1144 PetscFunctionBegin; 1145 ierr = PetscMalloc(jac->nsplits*sizeof(KSP),subksp);CHKERRQ(ierr); 1146 ierr = MatSchurComplementGetKSP(jac->schur,*subksp);CHKERRQ(ierr); 1147 1148 (*subksp)[1] = jac->kspschur; 1149 if (n) *n = jac->nsplits; 1150 PetscFunctionReturn(0); 1151 } 1152 1153 #undef __FUNCT__ 1154 #define __FUNCT__ "PCFieldSplitGetSubKSP_FieldSplit" 1155 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc,PetscInt *n,KSP **subksp) 1156 { 1157 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1158 PetscErrorCode ierr; 1159 PetscInt cnt = 0; 1160 PC_FieldSplitLink ilink = jac->head; 1161 1162 PetscFunctionBegin; 1163 ierr = PetscMalloc(jac->nsplits*sizeof(KSP),subksp);CHKERRQ(ierr); 1164 while (ilink) { 1165 (*subksp)[cnt++] = ilink->ksp; 1166 ilink = ilink->next; 1167 } 1168 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); 1169 if (n) *n = jac->nsplits; 1170 PetscFunctionReturn(0); 1171 } 1172 1173 #undef __FUNCT__ 1174 #define __FUNCT__ "PCFieldSplitSetIS_FieldSplit" 1175 static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc,const char splitname[],IS is) 1176 { 1177 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1178 PetscErrorCode ierr; 1179 PC_FieldSplitLink ilink, next = jac->head; 1180 char prefix[128]; 1181 1182 PetscFunctionBegin; 1183 if (jac->splitdefined) { 1184 ierr = PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);CHKERRQ(ierr); 1185 PetscFunctionReturn(0); 1186 } 1187 ierr = PetscNew(struct _PC_FieldSplitLink,&ilink);CHKERRQ(ierr); 1188 if (splitname) { 1189 ierr = PetscStrallocpy(splitname,&ilink->splitname);CHKERRQ(ierr); 1190 } else { 1191 ierr = PetscMalloc(8*sizeof(char),&ilink->splitname);CHKERRQ(ierr); 1192 ierr = PetscSNPrintf(ilink->splitname,7,"%D",jac->nsplits);CHKERRQ(ierr); 1193 } 1194 ierr = PetscObjectReference((PetscObject)is);CHKERRQ(ierr); 1195 ierr = ISDestroy(&ilink->is);CHKERRQ(ierr); 1196 ilink->is = is; 1197 ierr = PetscObjectReference((PetscObject)is);CHKERRQ(ierr); 1198 ierr = ISDestroy(&ilink->is_col);CHKERRQ(ierr); 1199 ilink->is_col = is; 1200 ilink->next = NULL; 1201 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);CHKERRQ(ierr); 1202 ierr = PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);CHKERRQ(ierr); 1203 ierr = KSPSetType(ilink->ksp,KSPPREONLY);CHKERRQ(ierr); 1204 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);CHKERRQ(ierr); 1205 1206 ierr = PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);CHKERRQ(ierr); 1207 ierr = KSPSetOptionsPrefix(ilink->ksp,prefix);CHKERRQ(ierr); 1208 1209 if (!next) { 1210 jac->head = ilink; 1211 ilink->previous = NULL; 1212 } else { 1213 while (next->next) { 1214 next = next->next; 1215 } 1216 next->next = ilink; 1217 ilink->previous = next; 1218 } 1219 jac->nsplits++; 1220 PetscFunctionReturn(0); 1221 } 1222 1223 #undef __FUNCT__ 1224 #define __FUNCT__ "PCFieldSplitSetFields" 1225 /*@ 1226 PCFieldSplitSetFields - Sets the fields for one particular split in the field split preconditioner 1227 1228 Logically Collective on PC 1229 1230 Input Parameters: 1231 + pc - the preconditioner context 1232 . splitname - name of this split, if NULL the number of the split is used 1233 . n - the number of fields in this split 1234 - fields - the fields in this split 1235 1236 Level: intermediate 1237 1238 Notes: Use PCFieldSplitSetIS() to set a completely general set of indices as a field. 1239 1240 The PCFieldSplitSetFields() is for defining fields as strided blocks. For example, if the block 1241 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 1242 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x1x3x5x7.. x12x45x78x.... 1243 where the numbered entries indicate what is in the field. 1244 1245 This function is called once per split (it creates a new split each time). Solve options 1246 for this split will be available under the prefix -fieldsplit_SPLITNAME_. 1247 1248 Developer Note: This routine does not actually create the IS representing the split, that is delayed 1249 until PCSetUp_FieldSplit(), because information about the vector/matrix layouts may not be 1250 available when this routine is called. 1251 1252 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize(), PCFieldSplitSetIS() 1253 1254 @*/ 1255 PetscErrorCode PCFieldSplitSetFields(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col) 1256 { 1257 PetscErrorCode ierr; 1258 1259 PetscFunctionBegin; 1260 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1261 PetscValidCharPointer(splitname,2); 1262 if (n < 1) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Provided number of fields %D in split \"%s\" not positive",n,splitname); 1263 PetscValidIntPointer(fields,3); 1264 ierr = PetscTryMethod(pc,"PCFieldSplitSetFields_C",(PC,const char[],PetscInt,const PetscInt*,const PetscInt*),(pc,splitname,n,fields,fields_col));CHKERRQ(ierr); 1265 PetscFunctionReturn(0); 1266 } 1267 1268 #undef __FUNCT__ 1269 #define __FUNCT__ "PCFieldSplitSetIS" 1270 /*@ 1271 PCFieldSplitSetIS - Sets the exact elements for field 1272 1273 Logically Collective on PC 1274 1275 Input Parameters: 1276 + pc - the preconditioner context 1277 . splitname - name of this split, if NULL the number of the split is used 1278 - is - the index set that defines the vector elements in this field 1279 1280 1281 Notes: 1282 Use PCFieldSplitSetFields(), for fields defined by strided types. 1283 1284 This function is called once per split (it creates a new split each time). Solve options 1285 for this split will be available under the prefix -fieldsplit_SPLITNAME_. 1286 1287 Level: intermediate 1288 1289 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize() 1290 1291 @*/ 1292 PetscErrorCode PCFieldSplitSetIS(PC pc,const char splitname[],IS is) 1293 { 1294 PetscErrorCode ierr; 1295 1296 PetscFunctionBegin; 1297 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1298 if (splitname) PetscValidCharPointer(splitname,2); 1299 PetscValidHeaderSpecific(is,IS_CLASSID,3); 1300 ierr = PetscTryMethod(pc,"PCFieldSplitSetIS_C",(PC,const char[],IS),(pc,splitname,is));CHKERRQ(ierr); 1301 PetscFunctionReturn(0); 1302 } 1303 1304 #undef __FUNCT__ 1305 #define __FUNCT__ "PCFieldSplitGetIS" 1306 /*@ 1307 PCFieldSplitGetIS - Retrieves the elements for a field as an IS 1308 1309 Logically Collective on PC 1310 1311 Input Parameters: 1312 + pc - the preconditioner context 1313 - splitname - name of this split 1314 1315 Output Parameter: 1316 - is - the index set that defines the vector elements in this field, or NULL if the field is not found 1317 1318 Level: intermediate 1319 1320 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetIS() 1321 1322 @*/ 1323 PetscErrorCode PCFieldSplitGetIS(PC pc,const char splitname[],IS *is) 1324 { 1325 PetscErrorCode ierr; 1326 1327 PetscFunctionBegin; 1328 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1329 PetscValidCharPointer(splitname,2); 1330 PetscValidPointer(is,3); 1331 { 1332 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1333 PC_FieldSplitLink ilink = jac->head; 1334 PetscBool found; 1335 1336 *is = NULL; 1337 while (ilink) { 1338 ierr = PetscStrcmp(ilink->splitname, splitname, &found);CHKERRQ(ierr); 1339 if (found) { 1340 *is = ilink->is; 1341 break; 1342 } 1343 ilink = ilink->next; 1344 } 1345 } 1346 PetscFunctionReturn(0); 1347 } 1348 1349 #undef __FUNCT__ 1350 #define __FUNCT__ "PCFieldSplitSetBlockSize" 1351 /*@ 1352 PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the 1353 fieldsplit preconditioner. If not set the matrix block size is used. 1354 1355 Logically Collective on PC 1356 1357 Input Parameters: 1358 + pc - the preconditioner context 1359 - bs - the block size 1360 1361 Level: intermediate 1362 1363 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields() 1364 1365 @*/ 1366 PetscErrorCode PCFieldSplitSetBlockSize(PC pc,PetscInt bs) 1367 { 1368 PetscErrorCode ierr; 1369 1370 PetscFunctionBegin; 1371 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1372 PetscValidLogicalCollectiveInt(pc,bs,2); 1373 ierr = PetscTryMethod(pc,"PCFieldSplitSetBlockSize_C",(PC,PetscInt),(pc,bs));CHKERRQ(ierr); 1374 PetscFunctionReturn(0); 1375 } 1376 1377 #undef __FUNCT__ 1378 #define __FUNCT__ "PCFieldSplitGetSubKSP" 1379 /*@C 1380 PCFieldSplitGetSubKSP - Gets the KSP contexts for all splits 1381 1382 Collective on KSP 1383 1384 Input Parameter: 1385 . pc - the preconditioner context 1386 1387 Output Parameters: 1388 + n - the number of splits 1389 - pc - the array of KSP contexts 1390 1391 Note: 1392 After PCFieldSplitGetSubKSP() the array of KSPs IS to be freed by the user 1393 (not the KSP just the array that contains them). 1394 1395 You must call KSPSetUp() before calling PCFieldSplitGetSubKSP(). 1396 1397 Fortran Usage: You must pass in a KSP array that is large enough to contain all the local KSPs. 1398 You can call PCFieldSplitGetSubKSP(pc,n,NULL_OBJECT,ierr) to determine how large the 1399 KSP array must be. 1400 1401 1402 Level: advanced 1403 1404 .seealso: PCFIELDSPLIT 1405 @*/ 1406 PetscErrorCode PCFieldSplitGetSubKSP(PC pc,PetscInt *n,KSP *subksp[]) 1407 { 1408 PetscErrorCode ierr; 1409 1410 PetscFunctionBegin; 1411 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1412 if (n) PetscValidIntPointer(n,2); 1413 ierr = PetscUseMethod(pc,"PCFieldSplitGetSubKSP_C",(PC,PetscInt*,KSP **),(pc,n,subksp));CHKERRQ(ierr); 1414 PetscFunctionReturn(0); 1415 } 1416 1417 #undef __FUNCT__ 1418 #define __FUNCT__ "PCFieldSplitSchurPrecondition" 1419 /*@ 1420 PCFieldSplitSchurPrecondition - Indicates if the Schur complement is preconditioned by a preconditioner constructed by the 1421 A11 matrix. Otherwise no preconditioner is used. 1422 1423 Collective on PC 1424 1425 Input Parameters: 1426 + pc - the preconditioner context 1427 . ptype - which matrix to use for preconditioning the Schur complement, PC_FIELDSPLIT_SCHUR_PRE_A11 (diag) is default 1428 - userpre - matrix to use for preconditioning, or NULL 1429 1430 Options Database: 1431 . -pc_fieldsplit_schur_precondition <self,user,a11> default is a11 1432 1433 Notes: 1434 $ If ptype is 1435 $ user then the preconditioner for the Schur complement is generated by the provided matrix (pre argument 1436 $ to this function). 1437 $ a11 then the preconditioner for the Schur complement is generated by the block diagonal part of the original 1438 $ matrix associated with the Schur complement (i.e. A11) 1439 $ self the preconditioner for the Schur complement is generated from the Schur complement matrix itself: 1440 $ The only preconditioner that currently works directly with the Schur complement matrix object is the PCLSC 1441 $ preconditioner 1442 1443 When solving a saddle point problem, where the A11 block is identically zero, using a11 as the ptype only makes sense 1444 with the additional option -fieldsplit_1_pc_type none. Usually for saddle point problems one would use a ptype of self and 1445 -fieldsplit_1_pc_type lsc which uses the least squares commutator compute a preconditioner for the Schur complement. 1446 1447 Developer Notes: This is a terrible name, gives no good indication of what the function does and should also have Set in 1448 the name since it sets a proceedure to use. 1449 1450 Level: intermediate 1451 1452 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType, PCLSC 1453 1454 @*/ 1455 PetscErrorCode PCFieldSplitSchurPrecondition(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) 1456 { 1457 PetscErrorCode ierr; 1458 1459 PetscFunctionBegin; 1460 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1461 ierr = PetscTryMethod(pc,"PCFieldSplitSchurPrecondition_C",(PC,PCFieldSplitSchurPreType,Mat),(pc,ptype,pre));CHKERRQ(ierr); 1462 PetscFunctionReturn(0); 1463 } 1464 1465 #undef __FUNCT__ 1466 #define __FUNCT__ "PCFieldSplitSchurPrecondition_FieldSplit" 1467 static PetscErrorCode PCFieldSplitSchurPrecondition_FieldSplit(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) 1468 { 1469 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1470 PetscErrorCode ierr; 1471 1472 PetscFunctionBegin; 1473 jac->schurpre = ptype; 1474 if (pre) { 1475 ierr = MatDestroy(&jac->schur_user);CHKERRQ(ierr); 1476 jac->schur_user = pre; 1477 ierr = PetscObjectReference((PetscObject)jac->schur_user);CHKERRQ(ierr); 1478 } 1479 PetscFunctionReturn(0); 1480 } 1481 1482 #undef __FUNCT__ 1483 #define __FUNCT__ "PCFieldSplitSetSchurFactType" 1484 /*@ 1485 PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain 1486 1487 Collective on PC 1488 1489 Input Parameters: 1490 + pc - the preconditioner context 1491 - ftype - which blocks of factorization to retain, PC_FIELDSPLIT_SCHUR_FACT_FULL is default 1492 1493 Options Database: 1494 . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> default is full 1495 1496 1497 Level: intermediate 1498 1499 Notes: 1500 The FULL factorization is 1501 1502 $ (A B) = (1 0) (A 0) (1 Ainv*B) 1503 $ (C D) (C*Ainv 1) (0 S) (0 1 ) 1504 1505 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, 1506 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). 1507 1508 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 1509 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 1510 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, 1511 the preconditioned operator has three distinct nonzero eigenvalues and minimal polynomial of degree at most 4, so KSPGMRES converges in at most 4 iterations. 1512 1513 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 1514 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). 1515 1516 References: 1517 Murphy, Golub, and Wathen, A note on preconditioning indefinite linear systems, SIAM J. Sci. Comput., 21 (2000) pp. 1969-1972. 1518 1519 Ipsen, A note on preconditioning nonsymmetric matrices, SIAM J. Sci. Comput., 23 (2001), pp. 1050-1051. 1520 1521 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType 1522 @*/ 1523 PetscErrorCode PCFieldSplitSetSchurFactType(PC pc,PCFieldSplitSchurFactType ftype) 1524 { 1525 PetscErrorCode ierr; 1526 1527 PetscFunctionBegin; 1528 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1529 ierr = PetscTryMethod(pc,"PCFieldSplitSetSchurFactType_C",(PC,PCFieldSplitSchurFactType),(pc,ftype));CHKERRQ(ierr); 1530 PetscFunctionReturn(0); 1531 } 1532 1533 #undef __FUNCT__ 1534 #define __FUNCT__ "PCFieldSplitSetSchurFactType_FieldSplit" 1535 static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc,PCFieldSplitSchurFactType ftype) 1536 { 1537 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1538 1539 PetscFunctionBegin; 1540 jac->schurfactorization = ftype; 1541 PetscFunctionReturn(0); 1542 } 1543 1544 #undef __FUNCT__ 1545 #define __FUNCT__ "PCFieldSplitGetSchurBlocks" 1546 /*@C 1547 PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement 1548 1549 Collective on KSP 1550 1551 Input Parameter: 1552 . pc - the preconditioner context 1553 1554 Output Parameters: 1555 + A00 - the (0,0) block 1556 . A01 - the (0,1) block 1557 . A10 - the (1,0) block 1558 - A11 - the (1,1) block 1559 1560 Level: advanced 1561 1562 .seealso: PCFIELDSPLIT 1563 @*/ 1564 PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc,Mat *A00,Mat *A01,Mat *A10, Mat *A11) 1565 { 1566 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1567 1568 PetscFunctionBegin; 1569 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1570 if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach."); 1571 if (A00) *A00 = jac->pmat[0]; 1572 if (A01) *A01 = jac->B; 1573 if (A10) *A10 = jac->C; 1574 if (A11) *A11 = jac->pmat[1]; 1575 PetscFunctionReturn(0); 1576 } 1577 1578 #undef __FUNCT__ 1579 #define __FUNCT__ "PCFieldSplitSetType_FieldSplit" 1580 static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc,PCCompositeType type) 1581 { 1582 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1583 PetscErrorCode ierr; 1584 1585 PetscFunctionBegin; 1586 jac->type = type; 1587 if (type == PC_COMPOSITE_SCHUR) { 1588 pc->ops->apply = PCApply_FieldSplit_Schur; 1589 pc->ops->view = PCView_FieldSplit_Schur; 1590 1591 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit_Schur);CHKERRQ(ierr); 1592 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurPrecondition_C",PCFieldSplitSchurPrecondition_FieldSplit);CHKERRQ(ierr); 1593 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",PCFieldSplitSetSchurFactType_FieldSplit);CHKERRQ(ierr); 1594 1595 } else { 1596 pc->ops->apply = PCApply_FieldSplit; 1597 pc->ops->view = PCView_FieldSplit; 1598 1599 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit);CHKERRQ(ierr); 1600 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurPrecondition_C",0);CHKERRQ(ierr); 1601 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",0);CHKERRQ(ierr); 1602 } 1603 PetscFunctionReturn(0); 1604 } 1605 1606 #undef __FUNCT__ 1607 #define __FUNCT__ "PCFieldSplitSetBlockSize_FieldSplit" 1608 static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc,PetscInt bs) 1609 { 1610 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1611 1612 PetscFunctionBegin; 1613 if (bs < 1) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Blocksize must be positive, you gave %D",bs); 1614 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); 1615 jac->bs = bs; 1616 PetscFunctionReturn(0); 1617 } 1618 1619 #undef __FUNCT__ 1620 #define __FUNCT__ "PCFieldSplitSetType" 1621 /*@ 1622 PCFieldSplitSetType - Sets the type of fieldsplit preconditioner. 1623 1624 Collective on PC 1625 1626 Input Parameter: 1627 . pc - the preconditioner context 1628 . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR 1629 1630 Options Database Key: 1631 . -pc_fieldsplit_type <type: one of multiplicative, additive, symmetric_multiplicative, special, schur> - Sets fieldsplit preconditioner type 1632 1633 Level: Intermediate 1634 1635 .keywords: PC, set, type, composite preconditioner, additive, multiplicative 1636 1637 .seealso: PCCompositeSetType() 1638 1639 @*/ 1640 PetscErrorCode PCFieldSplitSetType(PC pc,PCCompositeType type) 1641 { 1642 PetscErrorCode ierr; 1643 1644 PetscFunctionBegin; 1645 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1646 ierr = PetscTryMethod(pc,"PCFieldSplitSetType_C",(PC,PCCompositeType),(pc,type));CHKERRQ(ierr); 1647 PetscFunctionReturn(0); 1648 } 1649 1650 #undef __FUNCT__ 1651 #define __FUNCT__ "PCFieldSplitGetType" 1652 /*@ 1653 PCFieldSplitGetType - Gets the type of fieldsplit preconditioner. 1654 1655 Not collective 1656 1657 Input Parameter: 1658 . pc - the preconditioner context 1659 1660 Output Parameter: 1661 . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR 1662 1663 Level: Intermediate 1664 1665 .keywords: PC, set, type, composite preconditioner, additive, multiplicative 1666 .seealso: PCCompositeSetType() 1667 @*/ 1668 PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type) 1669 { 1670 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1671 1672 PetscFunctionBegin; 1673 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1674 PetscValidIntPointer(type,2); 1675 *type = jac->type; 1676 PetscFunctionReturn(0); 1677 } 1678 1679 #undef __FUNCT__ 1680 #define __FUNCT__ "PCFieldSplitSetDMSplits" 1681 /*@ 1682 PCFieldSplitSetDMSplits - Flags whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible. 1683 1684 Logically Collective 1685 1686 Input Parameters: 1687 + pc - the preconditioner context 1688 - flg - boolean indicating whether to use field splits defined by the DM 1689 1690 Options Database Key: 1691 . -pc_fieldsplit_dm_splits 1692 1693 Level: Intermediate 1694 1695 .keywords: PC, DM, composite preconditioner, additive, multiplicative 1696 1697 .seealso: PCFieldSplitGetDMSplits() 1698 1699 @*/ 1700 PetscErrorCode PCFieldSplitSetDMSplits(PC pc,PetscBool flg) 1701 { 1702 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1703 PetscBool isfs; 1704 PetscErrorCode ierr; 1705 1706 PetscFunctionBegin; 1707 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1708 PetscValidLogicalCollectiveBool(pc,flg,2); 1709 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1710 if (isfs) { 1711 jac->dm_splits = flg; 1712 } 1713 PetscFunctionReturn(0); 1714 } 1715 1716 1717 #undef __FUNCT__ 1718 #define __FUNCT__ "PCFieldSplitGetDMSplits" 1719 /*@ 1720 PCFieldSplitGetDMSplits - Returns flag indicating whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible. 1721 1722 Logically Collective 1723 1724 Input Parameter: 1725 . pc - the preconditioner context 1726 1727 Output Parameter: 1728 . flg - boolean indicating whether to use field splits defined by the DM 1729 1730 Level: Intermediate 1731 1732 .keywords: PC, DM, composite preconditioner, additive, multiplicative 1733 1734 .seealso: PCFieldSplitSetDMSplits() 1735 1736 @*/ 1737 PetscErrorCode PCFieldSplitGetDMSplits(PC pc,PetscBool* flg) 1738 { 1739 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1740 PetscBool isfs; 1741 PetscErrorCode ierr; 1742 1743 PetscFunctionBegin; 1744 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1745 PetscValidPointer(flg,2); 1746 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1747 if (isfs) { 1748 if(flg) *flg = jac->dm_splits; 1749 } 1750 PetscFunctionReturn(0); 1751 } 1752 1753 /* -------------------------------------------------------------------------------------*/ 1754 /*MC 1755 PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual 1756 fields or groups of fields. See the users manual section "Solving Block Matrices" for more details. 1757 1758 To set options on the solvers for each block append -fieldsplit_ to all the PC 1759 options database keys. For example, -fieldsplit_pc_type ilu -fieldsplit_pc_factor_levels 1 1760 1761 To set the options on the solvers separate for each block call PCFieldSplitGetSubKSP() 1762 and set the options directly on the resulting KSP object 1763 1764 Level: intermediate 1765 1766 Options Database Keys: 1767 + -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the %d'th split 1768 . -pc_fieldsplit_default - automatically add any fields to additional splits that have not 1769 been supplied explicitly by -pc_fieldsplit_%d_fields 1770 . -pc_fieldsplit_block_size <bs> - size of block that defines fields (i.e. there are bs fields) 1771 . -pc_fieldsplit_type <additive,multiplicative,symmetric_multiplicative,schur> - type of relaxation or factorization splitting 1772 . -pc_fieldsplit_schur_precondition <self,user,a11> - default is a11 1773 . -pc_fieldsplit_detect_saddle_point - automatically finds rows with zero or negative diagonal and uses Schur complement with no preconditioner as the solver 1774 1775 - Options prefix for inner solvers when using Schur complement preconditioner are -fieldsplit_0_ and -fieldsplit_1_ 1776 for all other solvers they are -fieldsplit_%d_ for the dth field, use -fieldsplit_ for all fields 1777 1778 Notes: 1779 Use PCFieldSplitSetFields() to set fields defined by "strided" entries and PCFieldSplitSetIS() 1780 to define a field by an arbitrary collection of entries. 1781 1782 If no fields are set the default is used. The fields are defined by entries strided by bs, 1783 beginning at 0 then 1, etc to bs-1. The block size can be set with PCFieldSplitSetBlockSize(), 1784 if this is not called the block size defaults to the blocksize of the second matrix passed 1785 to KSPSetOperators()/PCSetOperators(). 1786 1787 $ For the Schur complement preconditioner if J = ( A00 A01 ) 1788 $ ( A10 A11 ) 1789 $ the preconditioner using full factorization is 1790 $ ( I -A10 ksp(A00) ) ( inv(A00) 0 ) ( I 0 ) 1791 $ ( 0 I ) ( 0 ksp(S) ) ( -A10 ksp(A00) I ) 1792 where the action of inv(A00) is applied using the KSP solver with prefix -fieldsplit_0_. The action of 1793 ksp(S) is computed using the KSP solver with prefix -fieldsplit_splitname_ (where splitname was given 1794 in providing the SECOND split or 1 if not give). For PCFieldSplitGetKSP() when field number is 0, 1795 it returns the KSP associated with -fieldsplit_0_ while field number 1 gives -fieldsplit_1_ KSP. By default 1796 A11 is used to construct a preconditioner for S, use PCFieldSplitSchurPrecondition() to turn on or off this 1797 option. You can use the preconditioner PCLSC to precondition the Schur complement with -fieldsplit_1_pc_type lsc. The 1798 factorization type is set using -pc_fieldsplit_schur_fact_type <diag, lower, upper, full>. The full is shown above, 1799 diag gives 1800 $ ( inv(A00) 0 ) 1801 $ ( 0 -ksp(S) ) 1802 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 1803 $ ( A00 0 ) 1804 $ ( A10 S ) 1805 where the inverses of A00 and S are applied using KSPs. The upper factorization is the inverse of 1806 $ ( A00 A01 ) 1807 $ ( 0 S ) 1808 where again the inverses of A00 and S are applied using KSPs. 1809 1810 If only one set of indices (one IS) is provided with PCFieldSplitSetIS() then the complement of that IS 1811 is used automatically for a second block. 1812 1813 The fieldsplit preconditioner cannot currently be used with the BAIJ or SBAIJ data formats if the blocksize is larger than 1. 1814 Generally it should be used with the AIJ format. 1815 1816 The forms of these preconditioners are closely related if not identical to forms derived as "Distributive Iterations", see, 1817 for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling. Note that one can also use PCFIELDSPLIT 1818 inside a smoother resulting in "Distributive Smoothers". 1819 1820 Concepts: physics based preconditioners, block preconditioners 1821 1822 .seealso: PCCreate(), PCSetType(), PCType (for list of available types), PC, Block_Preconditioners, PCLSC, 1823 PCFieldSplitGetSubKSP(), PCFieldSplitSetFields(), PCFieldSplitSetType(), PCFieldSplitSetIS(), PCFieldSplitSchurPrecondition() 1824 M*/ 1825 1826 #undef __FUNCT__ 1827 #define __FUNCT__ "PCCreate_FieldSplit" 1828 PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc) 1829 { 1830 PetscErrorCode ierr; 1831 PC_FieldSplit *jac; 1832 1833 PetscFunctionBegin; 1834 ierr = PetscNewLog(pc,PC_FieldSplit,&jac);CHKERRQ(ierr); 1835 1836 jac->bs = -1; 1837 jac->nsplits = 0; 1838 jac->type = PC_COMPOSITE_MULTIPLICATIVE; 1839 jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */ 1840 jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL; 1841 jac->dm_splits = PETSC_TRUE; 1842 1843 pc->data = (void*)jac; 1844 1845 pc->ops->apply = PCApply_FieldSplit; 1846 pc->ops->applytranspose = PCApplyTranspose_FieldSplit; 1847 pc->ops->setup = PCSetUp_FieldSplit; 1848 pc->ops->reset = PCReset_FieldSplit; 1849 pc->ops->destroy = PCDestroy_FieldSplit; 1850 pc->ops->setfromoptions = PCSetFromOptions_FieldSplit; 1851 pc->ops->view = PCView_FieldSplit; 1852 pc->ops->applyrichardson = 0; 1853 1854 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit);CHKERRQ(ierr); 1855 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C",PCFieldSplitSetFields_FieldSplit);CHKERRQ(ierr); 1856 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C",PCFieldSplitSetIS_FieldSplit);CHKERRQ(ierr); 1857 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C",PCFieldSplitSetType_FieldSplit);CHKERRQ(ierr); 1858 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C",PCFieldSplitSetBlockSize_FieldSplit);CHKERRQ(ierr); 1859 PetscFunctionReturn(0); 1860 } 1861 1862 1863 1864