1 2 #include <petsc-private/pcimpl.h> /*I "petscpc.h" I*/ 3 #include <petscdm.h> 4 5 6 const char *const PCFieldSplitSchurPreTypes[] = {"SELF","SELFP","A11","USER","FULL","PCFieldSplitSchurPreType","PC_FIELDSPLIT_SCHUR_PRE_",0}; 7 const char *const PCFieldSplitSchurFactTypes[] = {"DIAG","LOWER","UPPER","FULL","PCFieldSplitSchurFactType","PC_FIELDSPLIT_SCHUR_FACT_",0}; 8 9 typedef struct _PC_FieldSplitLink *PC_FieldSplitLink; 10 struct _PC_FieldSplitLink { 11 KSP ksp; 12 Vec x,y,z; 13 char *splitname; 14 PetscInt nfields; 15 PetscInt *fields,*fields_col; 16 VecScatter sctx; 17 IS is,is_col; 18 PC_FieldSplitLink next,previous; 19 }; 20 21 typedef struct { 22 PCCompositeType type; 23 PetscBool defaultsplit; /* Flag for a system with a set of 'k' scalar fields with the same layout (and bs = k) */ 24 PetscBool splitdefined; /* Flag is set after the splits have been defined, to prevent more splits from being added */ 25 PetscInt bs; /* Block size for IS and Mat structures */ 26 PetscInt nsplits; /* Number of field divisions defined */ 27 Vec *x,*y,w1,w2; 28 Mat *mat; /* The diagonal block for each split */ 29 Mat *pmat; /* The preconditioning diagonal block for each split */ 30 Mat *Afield; /* The rows of the matrix associated with each split */ 31 PetscBool issetup; 32 33 /* Only used when Schur complement preconditioning is used */ 34 Mat B; /* The (0,1) block */ 35 Mat C; /* The (1,0) block */ 36 Mat schur; /* The Schur complement S = A11 - A10 A00^{-1} A01, the KSP here, kspinner, is H_1 in [El08] */ 37 Mat schurp; /* Assembled approximation to S built by MatSchurComplement to be used as a preconditioning matrix when solving with S */ 38 Mat schur_user; /* User-provided preconditioning matrix for the Schur complement */ 39 PCFieldSplitSchurPreType schurpre; /* Determines which preconditioning matrix is used for the Schur complement */ 40 PCFieldSplitSchurFactType schurfactorization; 41 KSP kspschur; /* The solver for S */ 42 KSP kspupper; /* The solver for A in the upper diagonal part of the factorization (H_2 in [El08]) */ 43 PC_FieldSplitLink head; 44 PetscBool reset; /* indicates PCReset() has been last called on this object, hack */ 45 PetscBool suboptionsset; /* Indicates that the KSPSetFromOptions() has been called on the sub-KSPs */ 46 PetscBool dm_splits; /* Whether to use DMCreateFieldDecomposition() whenever possible */ 47 PetscBool diag_use_amat; /* Whether to extract diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */ 48 PetscBool offdiag_use_amat; /* Whether to extract off-diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */ 49 } PC_FieldSplit; 50 51 /* 52 Notes: there is no particular reason that pmat, x, and y are stored as arrays in PC_FieldSplit instead of 53 inside PC_FieldSplitLink, just historical. If you want to be able to add new fields after already using the 54 PC you could change this. 55 */ 56 57 /* This helper is so that setting a user-provided preconditioning matrix is orthogonal to choosing to use it. This way the 58 * application-provided FormJacobian can provide this matrix without interfering with the user's (command-line) choices. */ 59 static Mat FieldSplitSchurPre(PC_FieldSplit *jac) 60 { 61 switch (jac->schurpre) { 62 case PC_FIELDSPLIT_SCHUR_PRE_SELF: return jac->schur; 63 case PC_FIELDSPLIT_SCHUR_PRE_SELFP: return jac->schurp; 64 case PC_FIELDSPLIT_SCHUR_PRE_A11: return jac->pmat[1]; 65 case PC_FIELDSPLIT_SCHUR_PRE_FULL: /* We calculate this and store it in schur_user */ 66 case PC_FIELDSPLIT_SCHUR_PRE_USER: /* Use a user-provided matrix if it is given, otherwise diagonal block */ 67 default: 68 return jac->schur_user ? jac->schur_user : jac->pmat[1]; 69 } 70 } 71 72 73 #include <petscdraw.h> 74 #undef __FUNCT__ 75 #define __FUNCT__ "PCView_FieldSplit" 76 static PetscErrorCode PCView_FieldSplit(PC pc,PetscViewer viewer) 77 { 78 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 79 PetscErrorCode ierr; 80 PetscBool iascii,isdraw; 81 PetscInt i,j; 82 PC_FieldSplitLink ilink = jac->head; 83 84 PetscFunctionBegin; 85 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr); 86 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr); 87 if (iascii) { 88 if (jac->bs > 0) { 89 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with %s composition: total splits = %D, blocksize = %D\n",PCCompositeTypes[jac->type],jac->nsplits,jac->bs);CHKERRQ(ierr); 90 } else { 91 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with %s composition: total splits = %D\n",PCCompositeTypes[jac->type],jac->nsplits);CHKERRQ(ierr); 92 } 93 if (pc->useAmat) { 94 ierr = PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for blocks\n");CHKERRQ(ierr); 95 } 96 if (jac->diag_use_amat) { 97 ierr = PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for diagonal blocks\n");CHKERRQ(ierr); 98 } 99 if (jac->offdiag_use_amat) { 100 ierr = PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for off-diagonal blocks\n");CHKERRQ(ierr); 101 } 102 ierr = PetscViewerASCIIPrintf(viewer," Solver info for each split is in the following KSP objects:\n");CHKERRQ(ierr); 103 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 104 for (i=0; i<jac->nsplits; i++) { 105 if (ilink->fields) { 106 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Fields ",i);CHKERRQ(ierr); 107 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr); 108 for (j=0; j<ilink->nfields; j++) { 109 if (j > 0) { 110 ierr = PetscViewerASCIIPrintf(viewer,",");CHKERRQ(ierr); 111 } 112 ierr = PetscViewerASCIIPrintf(viewer," %D",ilink->fields[j]);CHKERRQ(ierr); 113 } 114 ierr = PetscViewerASCIIPrintf(viewer,"\n");CHKERRQ(ierr); 115 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr); 116 } else { 117 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Defined by IS\n",i);CHKERRQ(ierr); 118 } 119 ierr = KSPView(ilink->ksp,viewer);CHKERRQ(ierr); 120 ilink = ilink->next; 121 } 122 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 123 } 124 125 if (isdraw) { 126 PetscDraw draw; 127 PetscReal x,y,w,wd; 128 129 ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr); 130 ierr = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr); 131 w = 2*PetscMin(1.0 - x,x); 132 wd = w/(jac->nsplits + 1); 133 x = x - wd*(jac->nsplits-1)/2.0; 134 for (i=0; i<jac->nsplits; i++) { 135 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 136 ierr = KSPView(ilink->ksp,viewer);CHKERRQ(ierr); 137 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 138 x += wd; 139 ilink = ilink->next; 140 } 141 } 142 PetscFunctionReturn(0); 143 } 144 145 #undef __FUNCT__ 146 #define __FUNCT__ "PCView_FieldSplit_Schur" 147 static PetscErrorCode PCView_FieldSplit_Schur(PC pc,PetscViewer viewer) 148 { 149 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 150 PetscErrorCode ierr; 151 PetscBool iascii,isdraw; 152 PetscInt i,j; 153 PC_FieldSplitLink ilink = jac->head; 154 155 PetscFunctionBegin; 156 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr); 157 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr); 158 if (iascii) { 159 if (jac->bs > 0) { 160 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with Schur preconditioner, blocksize = %D, factorization %s\n",jac->bs,PCFieldSplitSchurFactTypes[jac->schurfactorization]);CHKERRQ(ierr); 161 } else { 162 ierr = PetscViewerASCIIPrintf(viewer," FieldSplit with Schur preconditioner, factorization %s\n",PCFieldSplitSchurFactTypes[jac->schurfactorization]);CHKERRQ(ierr); 163 } 164 if (pc->useAmat) { 165 ierr = PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for blocks\n");CHKERRQ(ierr); 166 } 167 switch (jac->schurpre) { 168 case PC_FIELDSPLIT_SCHUR_PRE_SELF: 169 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from S itself\n");CHKERRQ(ierr);break; 170 case PC_FIELDSPLIT_SCHUR_PRE_SELFP: 171 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from Sp, an assembled approximation to S, which uses (the lumped) A00's diagonal's inverse\n");CHKERRQ(ierr);break; 172 case PC_FIELDSPLIT_SCHUR_PRE_A11: 173 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from A11\n");CHKERRQ(ierr);break; 174 case PC_FIELDSPLIT_SCHUR_PRE_FULL: 175 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from the exact Schur complement\n");CHKERRQ(ierr);break; 176 case PC_FIELDSPLIT_SCHUR_PRE_USER: 177 if (jac->schur_user) { 178 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from user provided matrix\n");CHKERRQ(ierr); 179 } else { 180 ierr = PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from A11\n");CHKERRQ(ierr); 181 } 182 break; 183 default: 184 SETERRQ1(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Invalid Schur preconditioning type: %d", jac->schurpre); 185 } 186 ierr = PetscViewerASCIIPrintf(viewer," Split info:\n");CHKERRQ(ierr); 187 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 188 for (i=0; i<jac->nsplits; i++) { 189 if (ilink->fields) { 190 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Fields ",i);CHKERRQ(ierr); 191 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr); 192 for (j=0; j<ilink->nfields; j++) { 193 if (j > 0) { 194 ierr = PetscViewerASCIIPrintf(viewer,",");CHKERRQ(ierr); 195 } 196 ierr = PetscViewerASCIIPrintf(viewer," %D",ilink->fields[j]);CHKERRQ(ierr); 197 } 198 ierr = PetscViewerASCIIPrintf(viewer,"\n");CHKERRQ(ierr); 199 ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr); 200 } else { 201 ierr = PetscViewerASCIIPrintf(viewer,"Split number %D Defined by IS\n",i);CHKERRQ(ierr); 202 } 203 ilink = ilink->next; 204 } 205 ierr = PetscViewerASCIIPrintf(viewer,"KSP solver for A00 block\n");CHKERRQ(ierr); 206 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 207 if (jac->head) { 208 ierr = KSPView(jac->head->ksp,viewer);CHKERRQ(ierr); 209 } else {ierr = PetscViewerASCIIPrintf(viewer," not yet available\n");CHKERRQ(ierr);} 210 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 211 if (jac->head && jac->kspupper != jac->head->ksp) { 212 ierr = PetscViewerASCIIPrintf(viewer,"KSP solver for upper A00 in upper triangular factor \n");CHKERRQ(ierr); 213 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 214 if (jac->kspupper) {ierr = KSPView(jac->kspupper,viewer);CHKERRQ(ierr);} 215 else {ierr = PetscViewerASCIIPrintf(viewer," not yet available\n");CHKERRQ(ierr);} 216 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 217 } 218 ierr = PetscViewerASCIIPrintf(viewer,"KSP solver for S = A11 - A10 inv(A00) A01 \n");CHKERRQ(ierr); 219 ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr); 220 if (jac->kspschur) { 221 ierr = KSPView(jac->kspschur,viewer);CHKERRQ(ierr); 222 } else { 223 ierr = PetscViewerASCIIPrintf(viewer," not yet available\n");CHKERRQ(ierr); 224 } 225 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 226 ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr); 227 } else if (isdraw && jac->head) { 228 PetscDraw draw; 229 PetscReal x,y,w,wd,h; 230 PetscInt cnt = 2; 231 char str[32]; 232 233 ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr); 234 ierr = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr); 235 if (jac->kspupper != jac->head->ksp) cnt++; 236 w = 2*PetscMin(1.0 - x,x); 237 wd = w/(cnt + 1); 238 239 ierr = PetscSNPrintf(str,32,"Schur fact. %s",PCFieldSplitSchurFactTypes[jac->schurfactorization]);CHKERRQ(ierr); 240 ierr = PetscDrawBoxedString(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);CHKERRQ(ierr); 241 y -= h; 242 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_USER && !jac->schur_user) { 243 ierr = PetscSNPrintf(str,32,"Prec. for Schur from %s",PCFieldSplitSchurPreTypes[PC_FIELDSPLIT_SCHUR_PRE_A11]);CHKERRQ(ierr); 244 } else { 245 ierr = PetscSNPrintf(str,32,"Prec. for Schur from %s",PCFieldSplitSchurPreTypes[jac->schurpre]);CHKERRQ(ierr); 246 } 247 ierr = PetscDrawBoxedString(draw,x+wd*(cnt-1)/2.0,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);CHKERRQ(ierr); 248 y -= h; 249 x = x - wd*(cnt-1)/2.0; 250 251 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 252 ierr = KSPView(jac->head->ksp,viewer);CHKERRQ(ierr); 253 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 254 if (jac->kspupper != jac->head->ksp) { 255 x += wd; 256 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 257 ierr = KSPView(jac->kspupper,viewer);CHKERRQ(ierr); 258 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 259 } 260 x += wd; 261 ierr = PetscDrawPushCurrentPoint(draw,x,y);CHKERRQ(ierr); 262 ierr = KSPView(jac->kspschur,viewer);CHKERRQ(ierr); 263 ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr); 264 } 265 PetscFunctionReturn(0); 266 } 267 268 #undef __FUNCT__ 269 #define __FUNCT__ "PCFieldSplitSetRuntimeSplits_Private" 270 /* Precondition: jac->bs is set to a meaningful value */ 271 static PetscErrorCode PCFieldSplitSetRuntimeSplits_Private(PC pc) 272 { 273 PetscErrorCode ierr; 274 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 275 PetscInt i,nfields,*ifields,nfields_col,*ifields_col; 276 PetscBool flg,flg_col; 277 char optionname[128],splitname[8],optionname_col[128]; 278 279 PetscFunctionBegin; 280 ierr = PetscMalloc1(jac->bs,&ifields);CHKERRQ(ierr); 281 ierr = PetscMalloc1(jac->bs,&ifields_col);CHKERRQ(ierr); 282 for (i=0,flg=PETSC_TRUE;; i++) { 283 ierr = PetscSNPrintf(splitname,sizeof(splitname),"%D",i);CHKERRQ(ierr); 284 ierr = PetscSNPrintf(optionname,sizeof(optionname),"-pc_fieldsplit_%D_fields",i);CHKERRQ(ierr); 285 ierr = PetscSNPrintf(optionname_col,sizeof(optionname_col),"-pc_fieldsplit_%D_fields_col",i);CHKERRQ(ierr); 286 nfields = jac->bs; 287 nfields_col = jac->bs; 288 ierr = PetscOptionsGetIntArray(((PetscObject)pc)->prefix,optionname,ifields,&nfields,&flg);CHKERRQ(ierr); 289 ierr = PetscOptionsGetIntArray(((PetscObject)pc)->prefix,optionname_col,ifields_col,&nfields_col,&flg_col);CHKERRQ(ierr); 290 if (!flg) break; 291 else if (flg && !flg_col) { 292 if (!nfields) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot list zero fields"); 293 ierr = PCFieldSplitSetFields(pc,splitname,nfields,ifields,ifields);CHKERRQ(ierr); 294 } else { 295 if (!nfields || !nfields_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot list zero fields"); 296 if (nfields != nfields_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Number of row and column fields must match"); 297 ierr = PCFieldSplitSetFields(pc,splitname,nfields,ifields,ifields_col);CHKERRQ(ierr); 298 } 299 } 300 if (i > 0) { 301 /* Makes command-line setting of splits take precedence over setting them in code. 302 Otherwise subsequent calls to PCFieldSplitSetIS() or PCFieldSplitSetFields() would 303 create new splits, which would probably not be what the user wanted. */ 304 jac->splitdefined = PETSC_TRUE; 305 } 306 ierr = PetscFree(ifields);CHKERRQ(ierr); 307 ierr = PetscFree(ifields_col);CHKERRQ(ierr); 308 PetscFunctionReturn(0); 309 } 310 311 #undef __FUNCT__ 312 #define __FUNCT__ "PCFieldSplitSetDefaults" 313 static PetscErrorCode PCFieldSplitSetDefaults(PC pc) 314 { 315 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 316 PetscErrorCode ierr; 317 PC_FieldSplitLink ilink = jac->head; 318 PetscBool fieldsplit_default = PETSC_FALSE,stokes = PETSC_FALSE,coupling = PETSC_FALSE; 319 PetscInt i; 320 321 PetscFunctionBegin; 322 /* 323 Kinda messy, but at least this now uses DMCreateFieldDecomposition() even with jac->reset. 324 Should probably be rewritten. 325 */ 326 if (!ilink || jac->reset) { 327 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr); 328 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_coupling",&coupling,NULL);CHKERRQ(ierr); 329 if (pc->dm && jac->dm_splits && !stokes && !coupling) { 330 PetscInt numFields, f, i, j; 331 char **fieldNames; 332 IS *fields; 333 DM *dms; 334 DM subdm[128]; 335 PetscBool flg; 336 337 ierr = DMCreateFieldDecomposition(pc->dm, &numFields, &fieldNames, &fields, &dms);CHKERRQ(ierr); 338 /* Allow the user to prescribe the splits */ 339 for (i = 0, flg = PETSC_TRUE;; i++) { 340 PetscInt ifields[128]; 341 IS compField; 342 char optionname[128], splitname[8]; 343 PetscInt nfields = numFields; 344 345 ierr = PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%D_fields", i);CHKERRQ(ierr); 346 ierr = PetscOptionsGetIntArray(((PetscObject) pc)->prefix, optionname, ifields, &nfields, &flg);CHKERRQ(ierr); 347 if (!flg) break; 348 if (numFields > 128) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot currently support %d > 128 fields", numFields); 349 ierr = DMCreateSubDM(pc->dm, nfields, ifields, &compField, &subdm[i]);CHKERRQ(ierr); 350 if (nfields == 1) { 351 ierr = PCFieldSplitSetIS(pc, fieldNames[ifields[0]], compField);CHKERRQ(ierr); 352 /* ierr = PetscPrintf(PetscObjectComm((PetscObject)pc), "%s Field Indices:", fieldNames[ifields[0]]);CHKERRQ(ierr); 353 ierr = ISView(compField, NULL);CHKERRQ(ierr); */ 354 } else { 355 ierr = PetscSNPrintf(splitname, sizeof(splitname), "%D", i);CHKERRQ(ierr); 356 ierr = PCFieldSplitSetIS(pc, splitname, compField);CHKERRQ(ierr); 357 /* ierr = PetscPrintf(PetscObjectComm((PetscObject)pc), "%s Field Indices:", splitname);CHKERRQ(ierr); 358 ierr = ISView(compField, NULL);CHKERRQ(ierr); */ 359 } 360 ierr = ISDestroy(&compField);CHKERRQ(ierr); 361 for (j = 0; j < nfields; ++j) { 362 f = ifields[j]; 363 ierr = PetscFree(fieldNames[f]);CHKERRQ(ierr); 364 ierr = ISDestroy(&fields[f]);CHKERRQ(ierr); 365 } 366 } 367 if (i == 0) { 368 for (f = 0; f < numFields; ++f) { 369 ierr = PCFieldSplitSetIS(pc, fieldNames[f], fields[f]);CHKERRQ(ierr); 370 ierr = PetscFree(fieldNames[f]);CHKERRQ(ierr); 371 ierr = ISDestroy(&fields[f]);CHKERRQ(ierr); 372 } 373 } else { 374 for (j=0; j<numFields; j++) { 375 ierr = DMDestroy(dms+j);CHKERRQ(ierr); 376 } 377 ierr = PetscFree(dms);CHKERRQ(ierr); 378 ierr = PetscMalloc1(i, &dms);CHKERRQ(ierr); 379 for (j = 0; j < i; ++j) dms[j] = subdm[j]; 380 } 381 ierr = PetscFree(fieldNames);CHKERRQ(ierr); 382 ierr = PetscFree(fields);CHKERRQ(ierr); 383 if (dms) { 384 ierr = PetscInfo(pc, "Setting up physics based fieldsplit preconditioner using the embedded DM\n");CHKERRQ(ierr); 385 for (ilink = jac->head, i = 0; ilink; ilink = ilink->next, ++i) { 386 const char *prefix; 387 ierr = PetscObjectGetOptionsPrefix((PetscObject)(ilink->ksp),&prefix);CHKERRQ(ierr); 388 ierr = PetscObjectSetOptionsPrefix((PetscObject)(dms[i]), prefix);CHKERRQ(ierr); 389 ierr = KSPSetDM(ilink->ksp, dms[i]);CHKERRQ(ierr); 390 ierr = KSPSetDMActive(ilink->ksp, PETSC_FALSE);CHKERRQ(ierr); 391 ierr = PetscObjectIncrementTabLevel((PetscObject)dms[i],(PetscObject)ilink->ksp,0);CHKERRQ(ierr); 392 ierr = DMDestroy(&dms[i]);CHKERRQ(ierr); 393 } 394 ierr = PetscFree(dms);CHKERRQ(ierr); 395 } 396 } else { 397 if (jac->bs <= 0) { 398 if (pc->pmat) { 399 ierr = MatGetBlockSize(pc->pmat,&jac->bs);CHKERRQ(ierr); 400 } else jac->bs = 1; 401 } 402 403 if (stokes) { 404 IS zerodiags,rest; 405 PetscInt nmin,nmax; 406 407 ierr = MatGetOwnershipRange(pc->mat,&nmin,&nmax);CHKERRQ(ierr); 408 ierr = MatFindZeroDiagonals(pc->mat,&zerodiags);CHKERRQ(ierr); 409 ierr = ISComplement(zerodiags,nmin,nmax,&rest);CHKERRQ(ierr); 410 if (jac->reset) { 411 jac->head->is = rest; 412 jac->head->next->is = zerodiags; 413 } else { 414 ierr = PCFieldSplitSetIS(pc,"0",rest);CHKERRQ(ierr); 415 ierr = PCFieldSplitSetIS(pc,"1",zerodiags);CHKERRQ(ierr); 416 } 417 ierr = ISDestroy(&zerodiags);CHKERRQ(ierr); 418 ierr = ISDestroy(&rest);CHKERRQ(ierr); 419 } else if (coupling) { 420 IS coupling,rest; 421 PetscInt nmin,nmax; 422 423 ierr = MatGetOwnershipRange(pc->mat,&nmin,&nmax);CHKERRQ(ierr); 424 ierr = MatFindOffBlockDiagonalEntries(pc->mat,&coupling);CHKERRQ(ierr); 425 ierr = ISCreateStride(PetscObjectComm((PetscObject)pc->mat),nmax-nmin,nmin,1,&rest);CHKERRQ(ierr); 426 if (jac->reset) { 427 jac->head->is = coupling; 428 jac->head->next->is = rest; 429 } else { 430 ierr = PCFieldSplitSetIS(pc,"0",coupling);CHKERRQ(ierr); 431 ierr = PCFieldSplitSetIS(pc,"1",rest);CHKERRQ(ierr); 432 } 433 ierr = ISDestroy(&coupling);CHKERRQ(ierr); 434 ierr = ISDestroy(&rest);CHKERRQ(ierr); 435 } else { 436 if (jac->reset) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cases not yet handled when PCReset() was used"); 437 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_default",&fieldsplit_default,NULL);CHKERRQ(ierr); 438 if (!fieldsplit_default) { 439 /* Allow user to set fields from command line, if bs was known at the time of PCSetFromOptions_FieldSplit() 440 then it is set there. This is not ideal because we should only have options set in XXSetFromOptions(). */ 441 ierr = PCFieldSplitSetRuntimeSplits_Private(pc);CHKERRQ(ierr); 442 if (jac->splitdefined) {ierr = PetscInfo(pc,"Splits defined using the options database\n");CHKERRQ(ierr);} 443 } 444 if (fieldsplit_default || !jac->splitdefined) { 445 ierr = PetscInfo(pc,"Using default splitting of fields\n");CHKERRQ(ierr); 446 for (i=0; i<jac->bs; i++) { 447 char splitname[8]; 448 ierr = PetscSNPrintf(splitname,sizeof(splitname),"%D",i);CHKERRQ(ierr); 449 ierr = PCFieldSplitSetFields(pc,splitname,1,&i,&i);CHKERRQ(ierr); 450 } 451 jac->defaultsplit = PETSC_TRUE; 452 } 453 } 454 } 455 } else if (jac->nsplits == 1) { 456 if (ilink->is) { 457 IS is2; 458 PetscInt nmin,nmax; 459 460 ierr = MatGetOwnershipRange(pc->mat,&nmin,&nmax);CHKERRQ(ierr); 461 ierr = ISComplement(ilink->is,nmin,nmax,&is2);CHKERRQ(ierr); 462 ierr = PCFieldSplitSetIS(pc,"1",is2);CHKERRQ(ierr); 463 ierr = ISDestroy(&is2);CHKERRQ(ierr); 464 } else SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Must provide at least two sets of fields to PCFieldSplit()"); 465 } 466 467 468 if (jac->nsplits < 2) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_PLIB,"Unhandled case, must have at least two fields, not %d", jac->nsplits); 469 PetscFunctionReturn(0); 470 } 471 472 PETSC_EXTERN PetscErrorCode PetscOptionsFindPairPrefix_Private(const char pre[], const char name[], char *value[], PetscBool *flg); 473 474 #undef __FUNCT__ 475 #define __FUNCT__ "PCSetUp_FieldSplit" 476 static PetscErrorCode PCSetUp_FieldSplit(PC pc) 477 { 478 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 479 PetscErrorCode ierr; 480 PC_FieldSplitLink ilink; 481 PetscInt i,nsplit; 482 PetscBool sorted, sorted_col; 483 484 PetscFunctionBegin; 485 ierr = PCFieldSplitSetDefaults(pc);CHKERRQ(ierr); 486 nsplit = jac->nsplits; 487 ilink = jac->head; 488 489 /* get the matrices for each split */ 490 if (!jac->issetup) { 491 PetscInt rstart,rend,nslots,bs; 492 493 jac->issetup = PETSC_TRUE; 494 495 /* This is done here instead of in PCFieldSplitSetFields() because may not have matrix at that point */ 496 if (jac->defaultsplit || !ilink->is) { 497 if (jac->bs <= 0) jac->bs = nsplit; 498 } 499 bs = jac->bs; 500 ierr = MatGetOwnershipRange(pc->pmat,&rstart,&rend);CHKERRQ(ierr); 501 nslots = (rend - rstart)/bs; 502 for (i=0; i<nsplit; i++) { 503 if (jac->defaultsplit) { 504 ierr = ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+i,nsplit,&ilink->is);CHKERRQ(ierr); 505 ierr = ISDuplicate(ilink->is,&ilink->is_col);CHKERRQ(ierr); 506 } else if (!ilink->is) { 507 if (ilink->nfields > 1) { 508 PetscInt *ii,*jj,j,k,nfields = ilink->nfields,*fields = ilink->fields,*fields_col = ilink->fields_col; 509 ierr = PetscMalloc1(ilink->nfields*nslots,&ii);CHKERRQ(ierr); 510 ierr = PetscMalloc1(ilink->nfields*nslots,&jj);CHKERRQ(ierr); 511 for (j=0; j<nslots; j++) { 512 for (k=0; k<nfields; k++) { 513 ii[nfields*j + k] = rstart + bs*j + fields[k]; 514 jj[nfields*j + k] = rstart + bs*j + fields_col[k]; 515 } 516 } 517 ierr = ISCreateGeneral(PetscObjectComm((PetscObject)pc),nslots*nfields,ii,PETSC_OWN_POINTER,&ilink->is);CHKERRQ(ierr); 518 ierr = ISCreateGeneral(PetscObjectComm((PetscObject)pc),nslots*nfields,jj,PETSC_OWN_POINTER,&ilink->is_col);CHKERRQ(ierr); 519 } else { 520 ierr = ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+ilink->fields[0],bs,&ilink->is);CHKERRQ(ierr); 521 ierr = ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+ilink->fields_col[0],bs,&ilink->is_col);CHKERRQ(ierr); 522 } 523 } 524 ierr = ISSorted(ilink->is,&sorted);CHKERRQ(ierr); 525 if (ilink->is_col) { ierr = ISSorted(ilink->is_col,&sorted_col);CHKERRQ(ierr); } 526 if (!sorted || !sorted_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Fields must be sorted when creating split"); 527 ilink = ilink->next; 528 } 529 } 530 531 ilink = jac->head; 532 if (!jac->pmat) { 533 Vec xtmp; 534 535 ierr = MatCreateVecs(pc->pmat,&xtmp,NULL);CHKERRQ(ierr); 536 ierr = PetscMalloc1(nsplit,&jac->pmat);CHKERRQ(ierr); 537 ierr = PetscMalloc2(nsplit,&jac->x,nsplit,&jac->y);CHKERRQ(ierr); 538 for (i=0; i<nsplit; i++) { 539 MatNullSpace sp; 540 541 /* Check for preconditioning matrix attached to IS */ 542 ierr = PetscObjectQuery((PetscObject) ilink->is, "pmat", (PetscObject*) &jac->pmat[i]);CHKERRQ(ierr); 543 if (jac->pmat[i]) { 544 ierr = PetscObjectReference((PetscObject) jac->pmat[i]);CHKERRQ(ierr); 545 if (jac->type == PC_COMPOSITE_SCHUR) { 546 jac->schur_user = jac->pmat[i]; 547 548 ierr = PetscObjectReference((PetscObject) jac->schur_user);CHKERRQ(ierr); 549 } 550 } else { 551 const char *prefix; 552 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ilink->is_col,MAT_INITIAL_MATRIX,&jac->pmat[i]);CHKERRQ(ierr); 553 ierr = KSPGetOptionsPrefix(ilink->ksp,&prefix);CHKERRQ(ierr); 554 ierr = MatSetOptionsPrefix(jac->pmat[i],prefix);CHKERRQ(ierr); 555 ierr = MatViewFromOptions(jac->pmat[i],NULL,"-mat_view");CHKERRQ(ierr); 556 } 557 /* create work vectors for each split */ 558 ierr = MatCreateVecs(jac->pmat[i],&jac->x[i],&jac->y[i]);CHKERRQ(ierr); 559 ilink->x = jac->x[i]; ilink->y = jac->y[i]; ilink->z = NULL; 560 /* compute scatter contexts needed by multiplicative versions and non-default splits */ 561 ierr = VecScatterCreate(xtmp,ilink->is,jac->x[i],NULL,&ilink->sctx);CHKERRQ(ierr); 562 /* Check for null space attached to IS */ 563 ierr = PetscObjectQuery((PetscObject) ilink->is, "nullspace", (PetscObject*) &sp);CHKERRQ(ierr); 564 if (sp) { 565 ierr = MatSetNullSpace(jac->pmat[i], sp);CHKERRQ(ierr); 566 } 567 ierr = PetscObjectQuery((PetscObject) ilink->is, "nearnullspace", (PetscObject*) &sp);CHKERRQ(ierr); 568 if (sp) { 569 ierr = MatSetNearNullSpace(jac->pmat[i], sp);CHKERRQ(ierr); 570 } 571 ilink = ilink->next; 572 } 573 ierr = VecDestroy(&xtmp);CHKERRQ(ierr); 574 } else { 575 for (i=0; i<nsplit; i++) { 576 Mat pmat; 577 578 /* Check for preconditioning matrix attached to IS */ 579 ierr = PetscObjectQuery((PetscObject) ilink->is, "pmat", (PetscObject*) &pmat);CHKERRQ(ierr); 580 if (!pmat) { 581 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ilink->is_col,MAT_REUSE_MATRIX,&jac->pmat[i]);CHKERRQ(ierr); 582 } 583 ilink = ilink->next; 584 } 585 } 586 if (jac->diag_use_amat) { 587 ilink = jac->head; 588 if (!jac->mat) { 589 ierr = PetscMalloc1(nsplit,&jac->mat);CHKERRQ(ierr); 590 for (i=0; i<nsplit; i++) { 591 ierr = MatGetSubMatrix(pc->mat,ilink->is,ilink->is_col,MAT_INITIAL_MATRIX,&jac->mat[i]);CHKERRQ(ierr); 592 ilink = ilink->next; 593 } 594 } else { 595 for (i=0; i<nsplit; i++) { 596 if (jac->mat[i]) {ierr = MatGetSubMatrix(pc->mat,ilink->is,ilink->is_col,MAT_REUSE_MATRIX,&jac->mat[i]);CHKERRQ(ierr);} 597 ilink = ilink->next; 598 } 599 } 600 } else { 601 jac->mat = jac->pmat; 602 } 603 604 if (jac->type != PC_COMPOSITE_ADDITIVE && jac->type != PC_COMPOSITE_SCHUR) { 605 /* extract the rows of the matrix associated with each field: used for efficient computation of residual inside algorithm */ 606 /* FIXME: Can/should we reuse jac->mat whenever (jac->diag_use_amat) is true? */ 607 ilink = jac->head; 608 if (!jac->Afield) { 609 ierr = PetscMalloc1(nsplit,&jac->Afield);CHKERRQ(ierr); 610 for (i=0; i<nsplit; i++) { 611 ierr = MatGetSubMatrix(pc->mat,ilink->is,NULL,MAT_INITIAL_MATRIX,&jac->Afield[i]);CHKERRQ(ierr); 612 ilink = ilink->next; 613 } 614 } else { 615 for (i=0; i<nsplit; i++) { 616 ierr = MatGetSubMatrix(pc->mat,ilink->is,NULL,MAT_REUSE_MATRIX,&jac->Afield[i]);CHKERRQ(ierr); 617 ilink = ilink->next; 618 } 619 } 620 } 621 622 if (jac->type == PC_COMPOSITE_SCHUR) { 623 IS ccis; 624 PetscInt rstart,rend; 625 char lscname[256]; 626 PetscObject LSC_L; 627 628 if (nsplit != 2) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_INCOMP,"To use Schur complement preconditioner you must have exactly 2 fields"); 629 630 /* When extracting off-diagonal submatrices, we take complements from this range */ 631 ierr = MatGetOwnershipRangeColumn(pc->mat,&rstart,&rend);CHKERRQ(ierr); 632 633 /* need to handle case when one is resetting up the preconditioner */ 634 if (jac->schur) { 635 KSP kspA = jac->head->ksp, kspInner = NULL, kspUpper = jac->kspupper; 636 637 ierr = MatSchurComplementGetKSP(jac->schur, &kspInner);CHKERRQ(ierr); 638 ilink = jac->head; 639 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 640 if (jac->offdiag_use_amat) { 641 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->B);CHKERRQ(ierr); 642 } else { 643 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->B);CHKERRQ(ierr); 644 } 645 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 646 ilink = ilink->next; 647 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 648 if (jac->offdiag_use_amat) { 649 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->C);CHKERRQ(ierr); 650 } else { 651 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->C);CHKERRQ(ierr); 652 } 653 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 654 ierr = MatSchurComplementUpdateSubMatrices(jac->schur,jac->mat[0],jac->pmat[0],jac->B,jac->C,jac->mat[1]);CHKERRQ(ierr); 655 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) { 656 ierr = MatDestroy(&jac->schurp);CHKERRQ(ierr); 657 ierr = MatSchurComplementGetPmat(jac->schur,MAT_INITIAL_MATRIX,&jac->schurp);CHKERRQ(ierr); 658 } 659 if (kspA != kspInner) { 660 ierr = KSPSetOperators(kspA,jac->mat[0],jac->pmat[0]);CHKERRQ(ierr); 661 } 662 if (kspUpper != kspA) { 663 ierr = KSPSetOperators(kspUpper,jac->mat[0],jac->pmat[0]);CHKERRQ(ierr); 664 } 665 ierr = KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac));CHKERRQ(ierr); 666 } else { 667 const char *Dprefix; 668 char schurprefix[256], schurmatprefix[256]; 669 char schurtestoption[256]; 670 MatNullSpace sp; 671 PetscBool flg; 672 673 /* extract the A01 and A10 matrices */ 674 ilink = jac->head; 675 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 676 if (jac->offdiag_use_amat) { 677 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->B);CHKERRQ(ierr); 678 } else { 679 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->B);CHKERRQ(ierr); 680 } 681 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 682 ilink = ilink->next; 683 ierr = ISComplement(ilink->is_col,rstart,rend,&ccis);CHKERRQ(ierr); 684 if (jac->offdiag_use_amat) { 685 ierr = MatGetSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->C);CHKERRQ(ierr); 686 } else { 687 ierr = MatGetSubMatrix(pc->pmat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->C);CHKERRQ(ierr); 688 } 689 ierr = ISDestroy(&ccis);CHKERRQ(ierr); 690 691 /* Use mat[0] (diagonal block of Amat) preconditioned by pmat[0] to define Schur complement */ 692 ierr = MatCreate(((PetscObject)jac->mat[0])->comm,&jac->schur);CHKERRQ(ierr); 693 ierr = MatSetType(jac->schur,MATSCHURCOMPLEMENT);CHKERRQ(ierr); 694 ierr = MatSchurComplementSetSubMatrices(jac->schur,jac->mat[0],jac->pmat[0],jac->B,jac->C,jac->mat[1]);CHKERRQ(ierr); 695 ierr = PetscSNPrintf(schurmatprefix, sizeof(schurmatprefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);CHKERRQ(ierr); 696 /* Note that the inner KSP is NOT going to inherit this prefix, and if it did, it would be reset just below. Is that what we want? */ 697 ierr = MatSetOptionsPrefix(jac->schur,schurmatprefix);CHKERRQ(ierr); 698 ierr = MatSetFromOptions(jac->schur);CHKERRQ(ierr); 699 ierr = MatGetNullSpace(jac->pmat[1], &sp);CHKERRQ(ierr); 700 if (sp) { 701 ierr = MatSetNullSpace(jac->schur, sp);CHKERRQ(ierr); 702 } 703 704 ierr = PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_inner_", ilink->splitname);CHKERRQ(ierr); 705 ierr = PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->prefix, schurtestoption, NULL, &flg);CHKERRQ(ierr); 706 if (flg) { 707 DM dmInner; 708 KSP kspInner; 709 710 ierr = MatSchurComplementGetKSP(jac->schur, &kspInner);CHKERRQ(ierr); 711 ierr = PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_inner_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);CHKERRQ(ierr); 712 /* Indent this deeper to emphasize the "inner" nature of this solver. */ 713 ierr = PetscObjectIncrementTabLevel((PetscObject)kspInner, (PetscObject) pc, 2);CHKERRQ(ierr); 714 ierr = KSPSetOptionsPrefix(kspInner, schurprefix);CHKERRQ(ierr); 715 716 /* Set DM for new solver */ 717 ierr = KSPGetDM(jac->head->ksp, &dmInner);CHKERRQ(ierr); 718 ierr = KSPSetDM(kspInner, dmInner);CHKERRQ(ierr); 719 ierr = KSPSetDMActive(kspInner, PETSC_FALSE);CHKERRQ(ierr); 720 } else { 721 /* Use the outer solver for the inner solve, but revert the KSPPREONLY from PCFieldSplitSetFields_FieldSplit or 722 * PCFieldSplitSetIS_FieldSplit. We don't want KSPPREONLY because it makes the Schur complement inexact, 723 * preventing Schur complement reduction to be an accurate solve. Usually when an iterative solver is used for 724 * S = D - C A_inner^{-1} B, we expect S to be defined using an accurate definition of A_inner^{-1}, so we make 725 * GMRES the default. Note that it is also common to use PREONLY for S, in which case S may not be used 726 * directly, and the user is responsible for setting an inexact method for fieldsplit's A^{-1}. */ 727 ierr = KSPSetType(jac->head->ksp,KSPGMRES);CHKERRQ(ierr); 728 ierr = MatSchurComplementSetKSP(jac->schur,jac->head->ksp);CHKERRQ(ierr); 729 } 730 ierr = KSPSetOperators(jac->head->ksp,jac->mat[0],jac->pmat[0]);CHKERRQ(ierr); 731 ierr = KSPSetFromOptions(jac->head->ksp);CHKERRQ(ierr); 732 ierr = MatSetFromOptions(jac->schur);CHKERRQ(ierr); 733 734 ierr = PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_upper_", ilink->splitname);CHKERRQ(ierr); 735 ierr = PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->prefix, schurtestoption, NULL, &flg);CHKERRQ(ierr); 736 if (flg) { 737 DM dmInner; 738 739 ierr = PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_upper_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);CHKERRQ(ierr); 740 ierr = KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspupper);CHKERRQ(ierr); 741 ierr = KSPSetOptionsPrefix(jac->kspupper, schurprefix);CHKERRQ(ierr); 742 ierr = KSPGetDM(jac->head->ksp, &dmInner);CHKERRQ(ierr); 743 ierr = KSPSetDM(jac->kspupper, dmInner);CHKERRQ(ierr); 744 ierr = KSPSetDMActive(jac->kspupper, PETSC_FALSE);CHKERRQ(ierr); 745 ierr = KSPSetFromOptions(jac->kspupper);CHKERRQ(ierr); 746 ierr = KSPSetOperators(jac->kspupper,jac->mat[0],jac->pmat[0]);CHKERRQ(ierr); 747 ierr = VecDuplicate(jac->head->x, &jac->head->z);CHKERRQ(ierr); 748 } else { 749 jac->kspupper = jac->head->ksp; 750 ierr = PetscObjectReference((PetscObject) jac->head->ksp);CHKERRQ(ierr); 751 } 752 753 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) { 754 ierr = MatSchurComplementGetPmat(jac->schur,MAT_INITIAL_MATRIX,&jac->schurp);CHKERRQ(ierr); 755 } 756 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&jac->kspschur);CHKERRQ(ierr); 757 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)jac->kspschur);CHKERRQ(ierr); 758 ierr = PetscObjectIncrementTabLevel((PetscObject)jac->kspschur,(PetscObject)pc,1);CHKERRQ(ierr); 759 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) { 760 PC pcschur; 761 ierr = KSPGetPC(jac->kspschur,&pcschur);CHKERRQ(ierr); 762 ierr = PCSetType(pcschur,PCNONE);CHKERRQ(ierr); 763 /* Note: This is bad if there exist preconditioners for MATSCHURCOMPLEMENT */ 764 } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL) { 765 ierr = MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user);CHKERRQ(ierr); 766 } 767 ierr = KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac));CHKERRQ(ierr); 768 ierr = KSPGetOptionsPrefix(jac->head->next->ksp, &Dprefix);CHKERRQ(ierr); 769 ierr = KSPSetOptionsPrefix(jac->kspschur, Dprefix);CHKERRQ(ierr); 770 /* propogate DM */ 771 { 772 DM sdm; 773 ierr = KSPGetDM(jac->head->next->ksp, &sdm);CHKERRQ(ierr); 774 if (sdm) { 775 ierr = KSPSetDM(jac->kspschur, sdm);CHKERRQ(ierr); 776 ierr = KSPSetDMActive(jac->kspschur, PETSC_FALSE);CHKERRQ(ierr); 777 } 778 } 779 /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */ 780 /* need to call this every time, since the jac->kspschur is freshly created, otherwise its options never get set */ 781 ierr = KSPSetFromOptions(jac->kspschur);CHKERRQ(ierr); 782 } 783 784 /* HACK: special support to forward L and Lp matrices that might be used by PCLSC */ 785 ierr = PetscSNPrintf(lscname,sizeof(lscname),"%s_LSC_L",ilink->splitname);CHKERRQ(ierr); 786 ierr = PetscObjectQuery((PetscObject)pc->mat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr); 787 if (!LSC_L) {ierr = PetscObjectQuery((PetscObject)pc->pmat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr);} 788 if (LSC_L) {ierr = PetscObjectCompose((PetscObject)jac->schur,"LSC_L",(PetscObject)LSC_L);CHKERRQ(ierr);} 789 ierr = PetscSNPrintf(lscname,sizeof(lscname),"%s_LSC_Lp",ilink->splitname);CHKERRQ(ierr); 790 ierr = PetscObjectQuery((PetscObject)pc->pmat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr); 791 if (!LSC_L) {ierr = PetscObjectQuery((PetscObject)pc->mat,lscname,(PetscObject*)&LSC_L);CHKERRQ(ierr);} 792 if (LSC_L) {ierr = PetscObjectCompose((PetscObject)jac->schur,"LSC_Lp",(PetscObject)LSC_L);CHKERRQ(ierr);} 793 } else { 794 /* set up the individual splits' PCs */ 795 i = 0; 796 ilink = jac->head; 797 while (ilink) { 798 ierr = KSPSetOperators(ilink->ksp,jac->mat[i],jac->pmat[i]);CHKERRQ(ierr); 799 /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */ 800 if (!jac->suboptionsset) {ierr = KSPSetFromOptions(ilink->ksp);CHKERRQ(ierr);} 801 i++; 802 ilink = ilink->next; 803 } 804 } 805 806 jac->suboptionsset = PETSC_TRUE; 807 PetscFunctionReturn(0); 808 } 809 810 #define FieldSplitSplitSolveAdd(ilink,xx,yy) \ 811 (VecScatterBegin(ilink->sctx,xx,ilink->x,INSERT_VALUES,SCATTER_FORWARD) || \ 812 VecScatterEnd(ilink->sctx,xx,ilink->x,INSERT_VALUES,SCATTER_FORWARD) || \ 813 KSPSolve(ilink->ksp,ilink->x,ilink->y) || \ 814 VecScatterBegin(ilink->sctx,ilink->y,yy,ADD_VALUES,SCATTER_REVERSE) || \ 815 VecScatterEnd(ilink->sctx,ilink->y,yy,ADD_VALUES,SCATTER_REVERSE)) 816 817 #undef __FUNCT__ 818 #define __FUNCT__ "PCApply_FieldSplit_Schur" 819 static PetscErrorCode PCApply_FieldSplit_Schur(PC pc,Vec x,Vec y) 820 { 821 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 822 PetscErrorCode ierr; 823 PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next; 824 KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper; 825 826 PetscFunctionBegin; 827 switch (jac->schurfactorization) { 828 case PC_FIELDSPLIT_SCHUR_FACT_DIAG: 829 /* [A00 0; 0 -S], positive definite, suitable for MINRES */ 830 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 831 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 832 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 833 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 834 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 835 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 836 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 837 ierr = VecScale(ilinkD->y,-1.);CHKERRQ(ierr); 838 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 839 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 840 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 841 break; 842 case PC_FIELDSPLIT_SCHUR_FACT_LOWER: 843 /* [A00 0; A10 S], suitable for left preconditioning */ 844 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 845 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 846 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 847 ierr = MatMult(jac->C,ilinkA->y,ilinkD->x);CHKERRQ(ierr); 848 ierr = VecScale(ilinkD->x,-1.);CHKERRQ(ierr); 849 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 850 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 851 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 852 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 853 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 854 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 855 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 856 break; 857 case PC_FIELDSPLIT_SCHUR_FACT_UPPER: 858 /* [A00 A01; 0 S], suitable for right preconditioning */ 859 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 860 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 861 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 862 ierr = MatMult(jac->B,ilinkD->y,ilinkA->x);CHKERRQ(ierr); 863 ierr = VecScale(ilinkA->x,-1.);CHKERRQ(ierr); 864 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 865 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 866 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 867 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 868 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 869 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 870 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 871 break; 872 case PC_FIELDSPLIT_SCHUR_FACT_FULL: 873 /* [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 */ 874 ierr = VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 875 ierr = VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 876 ierr = KSPSolve(kspLower,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 877 ierr = MatMult(jac->C,ilinkA->y,ilinkD->x);CHKERRQ(ierr); 878 ierr = VecScale(ilinkD->x,-1.0);CHKERRQ(ierr); 879 ierr = VecScatterBegin(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 880 ierr = VecScatterEnd(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 881 882 ierr = KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);CHKERRQ(ierr); 883 ierr = VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 884 ierr = VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 885 886 if (kspUpper == kspA) { 887 ierr = MatMult(jac->B,ilinkD->y,ilinkA->y);CHKERRQ(ierr); 888 ierr = VecAXPY(ilinkA->x,-1.0,ilinkA->y);CHKERRQ(ierr); 889 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 890 } else { 891 ierr = KSPSolve(kspA,ilinkA->x,ilinkA->y);CHKERRQ(ierr); 892 ierr = MatMult(jac->B,ilinkD->y,ilinkA->x);CHKERRQ(ierr); 893 ierr = KSPSolve(kspUpper,ilinkA->x,ilinkA->z);CHKERRQ(ierr); 894 ierr = VecAXPY(ilinkA->y,-1.0,ilinkA->z);CHKERRQ(ierr); 895 } 896 ierr = VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 897 ierr = VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 898 } 899 PetscFunctionReturn(0); 900 } 901 902 #undef __FUNCT__ 903 #define __FUNCT__ "PCApply_FieldSplit" 904 static PetscErrorCode PCApply_FieldSplit(PC pc,Vec x,Vec y) 905 { 906 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 907 PetscErrorCode ierr; 908 PC_FieldSplitLink ilink = jac->head; 909 PetscInt cnt,bs; 910 911 PetscFunctionBegin; 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 = KSPSolve(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 = FieldSplitSplitSolveAdd(ilink,x,y);CHKERRQ(ierr); 928 ilink = ilink->next; 929 } 930 } 931 } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 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 ierr = FieldSplitSplitSolveAdd(ilink,x,y);CHKERRQ(ierr); 938 cnt = 1; 939 while (ilink->next) { 940 ilink = ilink->next; 941 /* compute the residual only over the part of the vector needed */ 942 ierr = MatMult(jac->Afield[cnt++],y,ilink->x);CHKERRQ(ierr); 943 ierr = VecScale(ilink->x,-1.0);CHKERRQ(ierr); 944 ierr = VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 945 ierr = VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 946 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 947 ierr = VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 948 ierr = VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 949 } 950 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 951 cnt -= 2; 952 while (ilink->previous) { 953 ilink = ilink->previous; 954 /* compute the residual only over the part of the vector needed */ 955 ierr = MatMult(jac->Afield[cnt--],y,ilink->x);CHKERRQ(ierr); 956 ierr = VecScale(ilink->x,-1.0);CHKERRQ(ierr); 957 ierr = VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 958 ierr = VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 959 ierr = KSPSolve(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 960 ierr = VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 961 ierr = VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 962 } 963 } 964 } else SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Unsupported or unknown composition",(int) jac->type); 965 PetscFunctionReturn(0); 966 } 967 968 #define FieldSplitSplitSolveAddTranspose(ilink,xx,yy) \ 969 (VecScatterBegin(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \ 970 VecScatterEnd(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \ 971 KSPSolveTranspose(ilink->ksp,ilink->y,ilink->x) || \ 972 VecScatterBegin(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE) || \ 973 VecScatterEnd(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE)) 974 975 #undef __FUNCT__ 976 #define __FUNCT__ "PCApplyTranspose_FieldSplit" 977 static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc,Vec x,Vec y) 978 { 979 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 980 PetscErrorCode ierr; 981 PC_FieldSplitLink ilink = jac->head; 982 PetscInt bs; 983 984 PetscFunctionBegin; 985 if (jac->type == PC_COMPOSITE_ADDITIVE) { 986 if (jac->defaultsplit) { 987 ierr = VecGetBlockSize(x,&bs);CHKERRQ(ierr); 988 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); 989 ierr = VecGetBlockSize(y,&bs);CHKERRQ(ierr); 990 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); 991 ierr = VecStrideGatherAll(x,jac->x,INSERT_VALUES);CHKERRQ(ierr); 992 while (ilink) { 993 ierr = KSPSolveTranspose(ilink->ksp,ilink->x,ilink->y);CHKERRQ(ierr); 994 ilink = ilink->next; 995 } 996 ierr = VecStrideScatterAll(jac->y,y,INSERT_VALUES);CHKERRQ(ierr); 997 } else { 998 ierr = VecSet(y,0.0);CHKERRQ(ierr); 999 while (ilink) { 1000 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 1001 ilink = ilink->next; 1002 } 1003 } 1004 } else { 1005 if (!jac->w1) { 1006 ierr = VecDuplicate(x,&jac->w1);CHKERRQ(ierr); 1007 ierr = VecDuplicate(x,&jac->w2);CHKERRQ(ierr); 1008 } 1009 ierr = VecSet(y,0.0);CHKERRQ(ierr); 1010 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 1011 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 1012 while (ilink->next) { 1013 ilink = ilink->next; 1014 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 1015 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 1016 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 1017 } 1018 while (ilink->previous) { 1019 ilink = ilink->previous; 1020 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 1021 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 1022 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 1023 } 1024 } else { 1025 while (ilink->next) { /* get to last entry in linked list */ 1026 ilink = ilink->next; 1027 } 1028 ierr = FieldSplitSplitSolveAddTranspose(ilink,x,y);CHKERRQ(ierr); 1029 while (ilink->previous) { 1030 ilink = ilink->previous; 1031 ierr = MatMultTranspose(pc->mat,y,jac->w1);CHKERRQ(ierr); 1032 ierr = VecWAXPY(jac->w2,-1.0,jac->w1,x);CHKERRQ(ierr); 1033 ierr = FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);CHKERRQ(ierr); 1034 } 1035 } 1036 } 1037 PetscFunctionReturn(0); 1038 } 1039 1040 #undef __FUNCT__ 1041 #define __FUNCT__ "PCReset_FieldSplit" 1042 static PetscErrorCode PCReset_FieldSplit(PC pc) 1043 { 1044 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1045 PetscErrorCode ierr; 1046 PC_FieldSplitLink ilink = jac->head,next; 1047 1048 PetscFunctionBegin; 1049 while (ilink) { 1050 ierr = KSPReset(ilink->ksp);CHKERRQ(ierr); 1051 ierr = VecDestroy(&ilink->x);CHKERRQ(ierr); 1052 ierr = VecDestroy(&ilink->y);CHKERRQ(ierr); 1053 ierr = VecDestroy(&ilink->z);CHKERRQ(ierr); 1054 ierr = VecScatterDestroy(&ilink->sctx);CHKERRQ(ierr); 1055 ierr = ISDestroy(&ilink->is);CHKERRQ(ierr); 1056 ierr = ISDestroy(&ilink->is_col);CHKERRQ(ierr); 1057 next = ilink->next; 1058 ilink = next; 1059 } 1060 ierr = PetscFree2(jac->x,jac->y);CHKERRQ(ierr); 1061 if (jac->mat && jac->mat != jac->pmat) { 1062 ierr = MatDestroyMatrices(jac->nsplits,&jac->mat);CHKERRQ(ierr); 1063 } else if (jac->mat) { 1064 jac->mat = NULL; 1065 } 1066 if (jac->pmat) {ierr = MatDestroyMatrices(jac->nsplits,&jac->pmat);CHKERRQ(ierr);} 1067 if (jac->Afield) {ierr = MatDestroyMatrices(jac->nsplits,&jac->Afield);CHKERRQ(ierr);} 1068 ierr = VecDestroy(&jac->w1);CHKERRQ(ierr); 1069 ierr = VecDestroy(&jac->w2);CHKERRQ(ierr); 1070 ierr = MatDestroy(&jac->schur);CHKERRQ(ierr); 1071 ierr = MatDestroy(&jac->schurp);CHKERRQ(ierr); 1072 ierr = MatDestroy(&jac->schur_user);CHKERRQ(ierr); 1073 ierr = KSPDestroy(&jac->kspschur);CHKERRQ(ierr); 1074 ierr = KSPDestroy(&jac->kspupper);CHKERRQ(ierr); 1075 ierr = MatDestroy(&jac->B);CHKERRQ(ierr); 1076 ierr = MatDestroy(&jac->C);CHKERRQ(ierr); 1077 jac->reset = PETSC_TRUE; 1078 PetscFunctionReturn(0); 1079 } 1080 1081 #undef __FUNCT__ 1082 #define __FUNCT__ "PCDestroy_FieldSplit" 1083 static PetscErrorCode PCDestroy_FieldSplit(PC pc) 1084 { 1085 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1086 PetscErrorCode ierr; 1087 PC_FieldSplitLink ilink = jac->head,next; 1088 1089 PetscFunctionBegin; 1090 ierr = PCReset_FieldSplit(pc);CHKERRQ(ierr); 1091 while (ilink) { 1092 ierr = KSPDestroy(&ilink->ksp);CHKERRQ(ierr); 1093 next = ilink->next; 1094 ierr = PetscFree(ilink->splitname);CHKERRQ(ierr); 1095 ierr = PetscFree(ilink->fields);CHKERRQ(ierr); 1096 ierr = PetscFree(ilink->fields_col);CHKERRQ(ierr); 1097 ierr = PetscFree(ilink);CHKERRQ(ierr); 1098 ilink = next; 1099 } 1100 ierr = PetscFree2(jac->x,jac->y);CHKERRQ(ierr); 1101 ierr = PetscFree(pc->data);CHKERRQ(ierr); 1102 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",NULL);CHKERRQ(ierr); 1103 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C",NULL);CHKERRQ(ierr); 1104 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C",NULL);CHKERRQ(ierr); 1105 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C",NULL);CHKERRQ(ierr); 1106 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C",NULL);CHKERRQ(ierr); 1107 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurPre_C",NULL);CHKERRQ(ierr); 1108 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSchurPre_C",NULL);CHKERRQ(ierr); 1109 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",NULL);CHKERRQ(ierr); 1110 PetscFunctionReturn(0); 1111 } 1112 1113 #undef __FUNCT__ 1114 #define __FUNCT__ "PCSetFromOptions_FieldSplit" 1115 static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc) 1116 { 1117 PetscErrorCode ierr; 1118 PetscInt bs; 1119 PetscBool flg,stokes = PETSC_FALSE; 1120 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1121 PCCompositeType ctype; 1122 1123 PetscFunctionBegin; 1124 ierr = PetscOptionsHead("FieldSplit options");CHKERRQ(ierr); 1125 ierr = PetscOptionsBool("-pc_fieldsplit_dm_splits","Whether to use DMCreateFieldDecomposition() for splits","PCFieldSplitSetDMSplits",jac->dm_splits,&jac->dm_splits,NULL);CHKERRQ(ierr); 1126 ierr = PetscOptionsInt("-pc_fieldsplit_block_size","Blocksize that defines number of fields","PCFieldSplitSetBlockSize",jac->bs,&bs,&flg);CHKERRQ(ierr); 1127 if (flg) { 1128 ierr = PCFieldSplitSetBlockSize(pc,bs);CHKERRQ(ierr); 1129 } 1130 1131 ierr = PetscOptionsBool("-pc_fieldsplit_diag_use_amat","Use Amat (not Pmat) to extract diagonal fieldsplit blocks", "PCFieldSplitSetDiagUseAmat",pc->useAmat,&jac->diag_use_amat,NULL);CHKERRQ(ierr); 1132 ierr = PetscOptionsBool("-pc_fieldsplit_off_diag_use_amat","Use Amat (not Pmat) to extract off-diagonal fieldsplit blocks", "PCFieldSplitSetOffDiagUseAmat",pc->useAmat,&jac->offdiag_use_amat,NULL);CHKERRQ(ierr); 1133 /* FIXME: No programmatic equivalent to the following. */ 1134 ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr); 1135 if (stokes) { 1136 ierr = PCFieldSplitSetType(pc,PC_COMPOSITE_SCHUR);CHKERRQ(ierr); 1137 jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_SELF; 1138 } 1139 1140 ierr = PetscOptionsEnum("-pc_fieldsplit_type","Type of composition","PCFieldSplitSetType",PCCompositeTypes,(PetscEnum)jac->type,(PetscEnum*)&ctype,&flg);CHKERRQ(ierr); 1141 if (flg) { 1142 ierr = PCFieldSplitSetType(pc,ctype);CHKERRQ(ierr); 1143 } 1144 /* Only setup fields once */ 1145 if ((jac->bs > 0) && (jac->nsplits == 0)) { 1146 /* only allow user to set fields from command line if bs is already known. 1147 otherwise user can set them in PCFieldSplitSetDefaults() */ 1148 ierr = PCFieldSplitSetRuntimeSplits_Private(pc);CHKERRQ(ierr); 1149 if (jac->splitdefined) {ierr = PetscInfo(pc,"Splits defined using the options database\n");CHKERRQ(ierr);} 1150 } 1151 if (jac->type == PC_COMPOSITE_SCHUR) { 1152 ierr = PetscOptionsGetEnum(((PetscObject)pc)->prefix,"-pc_fieldsplit_schur_factorization_type",PCFieldSplitSchurFactTypes,(PetscEnum*)&jac->schurfactorization,&flg);CHKERRQ(ierr); 1153 if (flg) {ierr = PetscInfo(pc,"Deprecated use of -pc_fieldsplit_schur_factorization_type\n");CHKERRQ(ierr);} 1154 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); 1155 ierr = PetscOptionsEnum("-pc_fieldsplit_schur_precondition","How to build preconditioner for Schur complement","PCFieldSplitSetSchurPre",PCFieldSplitSchurPreTypes,(PetscEnum)jac->schurpre,(PetscEnum*)&jac->schurpre,NULL);CHKERRQ(ierr); 1156 } 1157 ierr = PetscOptionsTail();CHKERRQ(ierr); 1158 PetscFunctionReturn(0); 1159 } 1160 1161 /*------------------------------------------------------------------------------------*/ 1162 1163 #undef __FUNCT__ 1164 #define __FUNCT__ "PCFieldSplitSetFields_FieldSplit" 1165 static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col) 1166 { 1167 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1168 PetscErrorCode ierr; 1169 PC_FieldSplitLink ilink,next = jac->head; 1170 char prefix[128]; 1171 PetscInt i; 1172 1173 PetscFunctionBegin; 1174 if (jac->splitdefined) { 1175 ierr = PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);CHKERRQ(ierr); 1176 PetscFunctionReturn(0); 1177 } 1178 for (i=0; i<n; i++) { 1179 if (fields[i] >= jac->bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Field %D requested but only %D exist",fields[i],jac->bs); 1180 if (fields[i] < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative field %D requested",fields[i]); 1181 } 1182 ierr = PetscNew(&ilink);CHKERRQ(ierr); 1183 if (splitname) { 1184 ierr = PetscStrallocpy(splitname,&ilink->splitname);CHKERRQ(ierr); 1185 } else { 1186 ierr = PetscMalloc1(3,&ilink->splitname);CHKERRQ(ierr); 1187 ierr = PetscSNPrintf(ilink->splitname,2,"%s",jac->nsplits);CHKERRQ(ierr); 1188 } 1189 ierr = PetscMalloc1(n,&ilink->fields);CHKERRQ(ierr); 1190 ierr = PetscMemcpy(ilink->fields,fields,n*sizeof(PetscInt));CHKERRQ(ierr); 1191 ierr = PetscMalloc1(n,&ilink->fields_col);CHKERRQ(ierr); 1192 ierr = PetscMemcpy(ilink->fields_col,fields_col,n*sizeof(PetscInt));CHKERRQ(ierr); 1193 1194 ilink->nfields = n; 1195 ilink->next = NULL; 1196 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);CHKERRQ(ierr); 1197 ierr = PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);CHKERRQ(ierr); 1198 ierr = KSPSetType(ilink->ksp,KSPPREONLY);CHKERRQ(ierr); 1199 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);CHKERRQ(ierr); 1200 1201 ierr = PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);CHKERRQ(ierr); 1202 ierr = KSPSetOptionsPrefix(ilink->ksp,prefix);CHKERRQ(ierr); 1203 1204 if (!next) { 1205 jac->head = ilink; 1206 ilink->previous = NULL; 1207 } else { 1208 while (next->next) { 1209 next = next->next; 1210 } 1211 next->next = ilink; 1212 ilink->previous = next; 1213 } 1214 jac->nsplits++; 1215 PetscFunctionReturn(0); 1216 } 1217 1218 #undef __FUNCT__ 1219 #define __FUNCT__ "PCFieldSplitGetSubKSP_FieldSplit_Schur" 1220 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc,PetscInt *n,KSP **subksp) 1221 { 1222 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1223 PetscErrorCode ierr; 1224 1225 PetscFunctionBegin; 1226 ierr = PetscMalloc1(jac->nsplits,subksp);CHKERRQ(ierr); 1227 ierr = MatSchurComplementGetKSP(jac->schur,*subksp);CHKERRQ(ierr); 1228 1229 (*subksp)[1] = jac->kspschur; 1230 if (n) *n = jac->nsplits; 1231 PetscFunctionReturn(0); 1232 } 1233 1234 #undef __FUNCT__ 1235 #define __FUNCT__ "PCFieldSplitGetSubKSP_FieldSplit" 1236 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc,PetscInt *n,KSP **subksp) 1237 { 1238 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1239 PetscErrorCode ierr; 1240 PetscInt cnt = 0; 1241 PC_FieldSplitLink ilink = jac->head; 1242 1243 PetscFunctionBegin; 1244 ierr = PetscMalloc1(jac->nsplits,subksp);CHKERRQ(ierr); 1245 while (ilink) { 1246 (*subksp)[cnt++] = ilink->ksp; 1247 ilink = ilink->next; 1248 } 1249 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); 1250 if (n) *n = jac->nsplits; 1251 PetscFunctionReturn(0); 1252 } 1253 1254 #undef __FUNCT__ 1255 #define __FUNCT__ "PCFieldSplitSetIS_FieldSplit" 1256 static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc,const char splitname[],IS is) 1257 { 1258 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1259 PetscErrorCode ierr; 1260 PC_FieldSplitLink ilink, next = jac->head; 1261 char prefix[128]; 1262 1263 PetscFunctionBegin; 1264 if (jac->splitdefined) { 1265 ierr = PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);CHKERRQ(ierr); 1266 PetscFunctionReturn(0); 1267 } 1268 ierr = PetscNew(&ilink);CHKERRQ(ierr); 1269 if (splitname) { 1270 ierr = PetscStrallocpy(splitname,&ilink->splitname);CHKERRQ(ierr); 1271 } else { 1272 ierr = PetscMalloc1(8,&ilink->splitname);CHKERRQ(ierr); 1273 ierr = PetscSNPrintf(ilink->splitname,7,"%D",jac->nsplits);CHKERRQ(ierr); 1274 } 1275 ierr = PetscObjectReference((PetscObject)is);CHKERRQ(ierr); 1276 ierr = ISDestroy(&ilink->is);CHKERRQ(ierr); 1277 ilink->is = is; 1278 ierr = PetscObjectReference((PetscObject)is);CHKERRQ(ierr); 1279 ierr = ISDestroy(&ilink->is_col);CHKERRQ(ierr); 1280 ilink->is_col = is; 1281 ilink->next = NULL; 1282 ierr = KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);CHKERRQ(ierr); 1283 ierr = PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);CHKERRQ(ierr); 1284 ierr = KSPSetType(ilink->ksp,KSPPREONLY);CHKERRQ(ierr); 1285 ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);CHKERRQ(ierr); 1286 1287 ierr = PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);CHKERRQ(ierr); 1288 ierr = KSPSetOptionsPrefix(ilink->ksp,prefix);CHKERRQ(ierr); 1289 1290 if (!next) { 1291 jac->head = ilink; 1292 ilink->previous = NULL; 1293 } else { 1294 while (next->next) { 1295 next = next->next; 1296 } 1297 next->next = ilink; 1298 ilink->previous = next; 1299 } 1300 jac->nsplits++; 1301 PetscFunctionReturn(0); 1302 } 1303 1304 #undef __FUNCT__ 1305 #define __FUNCT__ "PCFieldSplitSetFields" 1306 /*@ 1307 PCFieldSplitSetFields - Sets the fields for one particular split in the field split preconditioner 1308 1309 Logically Collective on PC 1310 1311 Input Parameters: 1312 + pc - the preconditioner context 1313 . splitname - name of this split, if NULL the number of the split is used 1314 . n - the number of fields in this split 1315 - fields - the fields in this split 1316 1317 Level: intermediate 1318 1319 Notes: Use PCFieldSplitSetIS() to set a completely general set of indices as a field. 1320 1321 The PCFieldSplitSetFields() is for defining fields as strided blocks. For example, if the block 1322 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 1323 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x1x3x5x7.. x12x45x78x.... 1324 where the numbered entries indicate what is in the field. 1325 1326 This function is called once per split (it creates a new split each time). Solve options 1327 for this split will be available under the prefix -fieldsplit_SPLITNAME_. 1328 1329 Developer Note: This routine does not actually create the IS representing the split, that is delayed 1330 until PCSetUp_FieldSplit(), because information about the vector/matrix layouts may not be 1331 available when this routine is called. 1332 1333 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize(), PCFieldSplitSetIS() 1334 1335 @*/ 1336 PetscErrorCode PCFieldSplitSetFields(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col) 1337 { 1338 PetscErrorCode ierr; 1339 1340 PetscFunctionBegin; 1341 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1342 PetscValidCharPointer(splitname,2); 1343 if (n < 1) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Provided number of fields %D in split \"%s\" not positive",n,splitname); 1344 PetscValidIntPointer(fields,3); 1345 ierr = PetscTryMethod(pc,"PCFieldSplitSetFields_C",(PC,const char[],PetscInt,const PetscInt*,const PetscInt*),(pc,splitname,n,fields,fields_col));CHKERRQ(ierr); 1346 PetscFunctionReturn(0); 1347 } 1348 1349 #undef __FUNCT__ 1350 #define __FUNCT__ "PCFieldSplitSetDiagUseAmat" 1351 /*@ 1352 PCFieldSplitSetDiagUseAmat - set flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) 1353 1354 Logically Collective on PC 1355 1356 Input Parameters: 1357 + pc - the preconditioner object 1358 - flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from 1359 1360 Options Database: 1361 . -pc_fieldsplit_diag_use_amat 1362 1363 Level: intermediate 1364 1365 .seealso: PCFieldSplitGetDiagUseAmat(), PCFieldSplitSetOffDiagUseAmat(), PCFIELDSPLIT 1366 1367 @*/ 1368 PetscErrorCode PCFieldSplitSetDiagUseAmat(PC pc,PetscBool flg) 1369 { 1370 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1371 PetscBool isfs; 1372 PetscErrorCode ierr; 1373 1374 PetscFunctionBegin; 1375 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1376 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1377 if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT); 1378 jac->diag_use_amat = flg; 1379 PetscFunctionReturn(0); 1380 } 1381 1382 #undef __FUNCT__ 1383 #define __FUNCT__ "PCFieldSplitGetDiagUseAmat" 1384 /*@ 1385 PCFieldSplitGetDiagUseAmat - get the flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) 1386 1387 Logically Collective on PC 1388 1389 Input Parameters: 1390 . pc - the preconditioner object 1391 1392 Output Parameters: 1393 . flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from 1394 1395 1396 Level: intermediate 1397 1398 .seealso: PCFieldSplitSetDiagUseAmat(), PCFieldSplitGetOffDiagUseAmat(), PCFIELDSPLIT 1399 1400 @*/ 1401 PetscErrorCode PCFieldSplitGetDiagUseAmat(PC pc,PetscBool *flg) 1402 { 1403 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1404 PetscBool isfs; 1405 PetscErrorCode ierr; 1406 1407 PetscFunctionBegin; 1408 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1409 PetscValidPointer(flg,2); 1410 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1411 if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT); 1412 *flg = jac->diag_use_amat; 1413 PetscFunctionReturn(0); 1414 } 1415 1416 #undef __FUNCT__ 1417 #define __FUNCT__ "PCFieldSplitSetOffDiagUseAmat" 1418 /*@ 1419 PCFieldSplitSetOffDiagUseAmat - set flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) 1420 1421 Logically Collective on PC 1422 1423 Input Parameters: 1424 + pc - the preconditioner object 1425 - flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from 1426 1427 Options Database: 1428 . -pc_fieldsplit_off_diag_use_amat 1429 1430 Level: intermediate 1431 1432 .seealso: PCFieldSplitGetOffDiagUseAmat(), PCFieldSplitSetDiagUseAmat(), PCFIELDSPLIT 1433 1434 @*/ 1435 PetscErrorCode PCFieldSplitSetOffDiagUseAmat(PC pc,PetscBool flg) 1436 { 1437 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1438 PetscBool isfs; 1439 PetscErrorCode ierr; 1440 1441 PetscFunctionBegin; 1442 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1443 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1444 if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT); 1445 jac->offdiag_use_amat = flg; 1446 PetscFunctionReturn(0); 1447 } 1448 1449 #undef __FUNCT__ 1450 #define __FUNCT__ "PCFieldSplitGetOffDiagUseAmat" 1451 /*@ 1452 PCFieldSplitGetOffDiagUseAmat - get the flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) 1453 1454 Logically Collective on PC 1455 1456 Input Parameters: 1457 . pc - the preconditioner object 1458 1459 Output Parameters: 1460 . flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from 1461 1462 1463 Level: intermediate 1464 1465 .seealso: PCFieldSplitSetOffDiagUseAmat(), PCFieldSplitGetDiagUseAmat(), PCFIELDSPLIT 1466 1467 @*/ 1468 PetscErrorCode PCFieldSplitGetOffDiagUseAmat(PC pc,PetscBool *flg) 1469 { 1470 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1471 PetscBool isfs; 1472 PetscErrorCode ierr; 1473 1474 PetscFunctionBegin; 1475 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1476 PetscValidPointer(flg,2); 1477 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1478 if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT); 1479 *flg = jac->offdiag_use_amat; 1480 PetscFunctionReturn(0); 1481 } 1482 1483 1484 1485 #undef __FUNCT__ 1486 #define __FUNCT__ "PCFieldSplitSetIS" 1487 /*@ 1488 PCFieldSplitSetIS - Sets the exact elements for field 1489 1490 Logically Collective on PC 1491 1492 Input Parameters: 1493 + pc - the preconditioner context 1494 . splitname - name of this split, if NULL the number of the split is used 1495 - is - the index set that defines the vector elements in this field 1496 1497 1498 Notes: 1499 Use PCFieldSplitSetFields(), for fields defined by strided types. 1500 1501 This function is called once per split (it creates a new split each time). Solve options 1502 for this split will be available under the prefix -fieldsplit_SPLITNAME_. 1503 1504 Level: intermediate 1505 1506 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize() 1507 1508 @*/ 1509 PetscErrorCode PCFieldSplitSetIS(PC pc,const char splitname[],IS is) 1510 { 1511 PetscErrorCode ierr; 1512 1513 PetscFunctionBegin; 1514 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1515 if (splitname) PetscValidCharPointer(splitname,2); 1516 PetscValidHeaderSpecific(is,IS_CLASSID,3); 1517 ierr = PetscTryMethod(pc,"PCFieldSplitSetIS_C",(PC,const char[],IS),(pc,splitname,is));CHKERRQ(ierr); 1518 PetscFunctionReturn(0); 1519 } 1520 1521 #undef __FUNCT__ 1522 #define __FUNCT__ "PCFieldSplitGetIS" 1523 /*@ 1524 PCFieldSplitGetIS - Retrieves the elements for a field as an IS 1525 1526 Logically Collective on PC 1527 1528 Input Parameters: 1529 + pc - the preconditioner context 1530 - splitname - name of this split 1531 1532 Output Parameter: 1533 - is - the index set that defines the vector elements in this field, or NULL if the field is not found 1534 1535 Level: intermediate 1536 1537 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetIS() 1538 1539 @*/ 1540 PetscErrorCode PCFieldSplitGetIS(PC pc,const char splitname[],IS *is) 1541 { 1542 PetscErrorCode ierr; 1543 1544 PetscFunctionBegin; 1545 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1546 PetscValidCharPointer(splitname,2); 1547 PetscValidPointer(is,3); 1548 { 1549 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1550 PC_FieldSplitLink ilink = jac->head; 1551 PetscBool found; 1552 1553 *is = NULL; 1554 while (ilink) { 1555 ierr = PetscStrcmp(ilink->splitname, splitname, &found);CHKERRQ(ierr); 1556 if (found) { 1557 *is = ilink->is; 1558 break; 1559 } 1560 ilink = ilink->next; 1561 } 1562 } 1563 PetscFunctionReturn(0); 1564 } 1565 1566 #undef __FUNCT__ 1567 #define __FUNCT__ "PCFieldSplitSetBlockSize" 1568 /*@ 1569 PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the 1570 fieldsplit preconditioner. If not set the matrix block size is used. 1571 1572 Logically Collective on PC 1573 1574 Input Parameters: 1575 + pc - the preconditioner context 1576 - bs - the block size 1577 1578 Level: intermediate 1579 1580 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields() 1581 1582 @*/ 1583 PetscErrorCode PCFieldSplitSetBlockSize(PC pc,PetscInt bs) 1584 { 1585 PetscErrorCode ierr; 1586 1587 PetscFunctionBegin; 1588 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1589 PetscValidLogicalCollectiveInt(pc,bs,2); 1590 ierr = PetscTryMethod(pc,"PCFieldSplitSetBlockSize_C",(PC,PetscInt),(pc,bs));CHKERRQ(ierr); 1591 PetscFunctionReturn(0); 1592 } 1593 1594 #undef __FUNCT__ 1595 #define __FUNCT__ "PCFieldSplitGetSubKSP" 1596 /*@C 1597 PCFieldSplitGetSubKSP - Gets the KSP contexts for all splits 1598 1599 Collective on KSP 1600 1601 Input Parameter: 1602 . pc - the preconditioner context 1603 1604 Output Parameters: 1605 + n - the number of splits 1606 - pc - the array of KSP contexts 1607 1608 Note: 1609 After PCFieldSplitGetSubKSP() the array of KSPs IS to be freed by the user 1610 (not the KSP just the array that contains them). 1611 1612 You must call KSPSetUp() before calling PCFieldSplitGetSubKSP(). 1613 1614 Fortran Usage: You must pass in a KSP array that is large enough to contain all the local KSPs. 1615 You can call PCFieldSplitGetSubKSP(pc,n,NULL_OBJECT,ierr) to determine how large the 1616 KSP array must be. 1617 1618 1619 Level: advanced 1620 1621 .seealso: PCFIELDSPLIT 1622 @*/ 1623 PetscErrorCode PCFieldSplitGetSubKSP(PC pc,PetscInt *n,KSP *subksp[]) 1624 { 1625 PetscErrorCode ierr; 1626 1627 PetscFunctionBegin; 1628 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1629 if (n) PetscValidIntPointer(n,2); 1630 ierr = PetscUseMethod(pc,"PCFieldSplitGetSubKSP_C",(PC,PetscInt*,KSP **),(pc,n,subksp));CHKERRQ(ierr); 1631 PetscFunctionReturn(0); 1632 } 1633 1634 #undef __FUNCT__ 1635 #define __FUNCT__ "PCFieldSplitSetSchurPre" 1636 /*@ 1637 PCFieldSplitSetSchurPre - Indicates if the Schur complement is preconditioned by a preconditioner constructed by the 1638 A11 matrix. Otherwise no preconditioner is used. 1639 1640 Collective on PC 1641 1642 Input Parameters: 1643 + pc - the preconditioner context 1644 . ptype - which matrix to use for preconditioning the Schur complement: PC_FIELDSPLIT_SCHUR_PRE_A11 (default), PC_FIELDSPLIT_SCHUR_PRE_SELF, PC_FIELDSPLIT_PRE_USER 1645 - userpre - matrix to use for preconditioning, or NULL 1646 1647 Options Database: 1648 . -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> default is a11 1649 1650 Notes: 1651 $ If ptype is 1652 $ user then the preconditioner for the Schur complement is generated by the provided matrix (pre argument 1653 $ to this function). 1654 $ a11 then the preconditioner for the Schur complement is generated by the block diagonal part of the preconditioner 1655 $ matrix associated with the Schur complement (i.e. A11), not he Schur complement matrix 1656 $ full then the preconditioner uses the exact Schur complement (this is expensive) 1657 $ self the preconditioner for the Schur complement is generated from the Schur complement matrix itself: 1658 $ The only preconditioner that currently works directly with the Schur complement matrix object is the PCLSC 1659 $ preconditioner 1660 $ selfp then the preconditioning matrix is an explicitly-assembled approximation Sp = A11 - A10 inv(diag(A00)) A01 1661 $ This is only a good preconditioner when diag(A00) is a good preconditioner for A00. 1662 1663 When solving a saddle point problem, where the A11 block is identically zero, using a11 as the ptype only makes sense 1664 with the additional option -fieldsplit_1_pc_type none. Usually for saddle point problems one would use a ptype of self and 1665 -fieldsplit_1_pc_type lsc which uses the least squares commutator to compute a preconditioner for the Schur complement. 1666 1667 Level: intermediate 1668 1669 .seealso: PCFieldSplitGetSchurPre(), PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType, PCLSC 1670 1671 @*/ 1672 PetscErrorCode PCFieldSplitSetSchurPre(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) 1673 { 1674 PetscErrorCode ierr; 1675 1676 PetscFunctionBegin; 1677 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1678 ierr = PetscTryMethod(pc,"PCFieldSplitSetSchurPre_C",(PC,PCFieldSplitSchurPreType,Mat),(pc,ptype,pre));CHKERRQ(ierr); 1679 PetscFunctionReturn(0); 1680 } 1681 PetscErrorCode PCFieldSplitSchurPrecondition(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) {return PCFieldSplitSetSchurPre(pc,ptype,pre);} /* Deprecated name */ 1682 1683 #undef __FUNCT__ 1684 #define __FUNCT__ "PCFieldSplitGetSchurPre" 1685 /*@ 1686 PCFieldSplitGetSchurPre - For Schur complement fieldsplit, determine how the Schur complement will be 1687 preconditioned. See PCFieldSplitSetSchurPre() for details. 1688 1689 Logically Collective on PC 1690 1691 Input Parameters: 1692 . pc - the preconditioner context 1693 1694 Output Parameters: 1695 + ptype - which matrix to use for preconditioning the Schur complement: PC_FIELDSPLIT_SCHUR_PRE_A11, PC_FIELDSPLIT_SCHUR_PRE_SELF, PC_FIELDSPLIT_PRE_USER 1696 - userpre - matrix to use for preconditioning (with PC_FIELDSPLIT_PRE_USER), or NULL 1697 1698 Level: intermediate 1699 1700 .seealso: PCFieldSplitSetSchurPre(), PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType, PCLSC 1701 1702 @*/ 1703 PetscErrorCode PCFieldSplitGetSchurPre(PC pc,PCFieldSplitSchurPreType *ptype,Mat *pre) 1704 { 1705 PetscErrorCode ierr; 1706 1707 PetscFunctionBegin; 1708 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1709 ierr = PetscUseMethod(pc,"PCFieldSplitGetSchurPre_C",(PC,PCFieldSplitSchurPreType*,Mat*),(pc,ptype,pre));CHKERRQ(ierr); 1710 PetscFunctionReturn(0); 1711 } 1712 1713 #undef __FUNCT__ 1714 #define __FUNCT__ "PCFieldSplitSchurGetS" 1715 /*@ 1716 PCFieldSplitSchurGetS - extract the MatSchurComplement object used by this PC in case it needs to be configured separately 1717 1718 Not collective 1719 1720 Input Parameter: 1721 . pc - the preconditioner context 1722 1723 Output Parameter: 1724 . S - the Schur complement matrix 1725 1726 Notes: 1727 This matrix should not be destroyed using MatDestroy(); rather, use PCFieldSplitSchurRestoreS(). 1728 1729 Level: advanced 1730 1731 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSchurPreType, PCFieldSplitSetSchurPre(), MatSchurComplement, PCFieldSplitSchurRestoreS() 1732 1733 @*/ 1734 PetscErrorCode PCFieldSplitSchurGetS(PC pc,Mat *S) 1735 { 1736 PetscErrorCode ierr; 1737 const char* t; 1738 PetscBool isfs; 1739 PC_FieldSplit *jac; 1740 1741 PetscFunctionBegin; 1742 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1743 ierr = PetscObjectGetType((PetscObject)pc,&t);CHKERRQ(ierr); 1744 ierr = PetscStrcmp(t,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1745 if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PC of type PCFIELDSPLIT, got %s instead",t); 1746 jac = (PC_FieldSplit*)pc->data; 1747 if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PCFIELDSPLIT of type SCHUR, got %D instead",jac->type); 1748 if (S) *S = jac->schur; 1749 PetscFunctionReturn(0); 1750 } 1751 1752 #undef __FUNCT__ 1753 #define __FUNCT__ "PCFieldSplitSchurRestoreS" 1754 /*@ 1755 PCFieldSplitSchurRestoreS - restores the MatSchurComplement object used by this PC 1756 1757 Not collective 1758 1759 Input Parameters: 1760 + pc - the preconditioner context 1761 . S - the Schur complement matrix 1762 1763 Level: advanced 1764 1765 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSchurPreType, PCFieldSplitSetSchurPre(), MatSchurComplement, PCFieldSplitSchurGetS() 1766 1767 @*/ 1768 PetscErrorCode PCFieldSplitSchurRestoreS(PC pc,Mat *S) 1769 { 1770 PetscErrorCode ierr; 1771 const char* t; 1772 PetscBool isfs; 1773 PC_FieldSplit *jac; 1774 1775 PetscFunctionBegin; 1776 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1777 ierr = PetscObjectGetType((PetscObject)pc,&t);CHKERRQ(ierr); 1778 ierr = PetscStrcmp(t,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 1779 if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PC of type PCFIELDSPLIT, got %s instead",t); 1780 jac = (PC_FieldSplit*)pc->data; 1781 if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PCFIELDSPLIT of type SCHUR, got %D instead",jac->type); 1782 if (!S || *S != jac->schur) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"MatSchurComplement restored is not the same as gotten"); 1783 PetscFunctionReturn(0); 1784 } 1785 1786 1787 #undef __FUNCT__ 1788 #define __FUNCT__ "PCFieldSplitSetSchurPre_FieldSplit" 1789 static PetscErrorCode PCFieldSplitSetSchurPre_FieldSplit(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) 1790 { 1791 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1792 PetscErrorCode ierr; 1793 1794 PetscFunctionBegin; 1795 jac->schurpre = ptype; 1796 if (ptype == PC_FIELDSPLIT_SCHUR_PRE_USER && pre) { 1797 ierr = MatDestroy(&jac->schur_user);CHKERRQ(ierr); 1798 jac->schur_user = pre; 1799 ierr = PetscObjectReference((PetscObject)jac->schur_user);CHKERRQ(ierr); 1800 } 1801 PetscFunctionReturn(0); 1802 } 1803 1804 #undef __FUNCT__ 1805 #define __FUNCT__ "PCFieldSplitGetSchurPre_FieldSplit" 1806 static PetscErrorCode PCFieldSplitGetSchurPre_FieldSplit(PC pc,PCFieldSplitSchurPreType *ptype,Mat *pre) 1807 { 1808 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1809 1810 PetscFunctionBegin; 1811 *ptype = jac->schurpre; 1812 *pre = jac->schur_user; 1813 PetscFunctionReturn(0); 1814 } 1815 1816 #undef __FUNCT__ 1817 #define __FUNCT__ "PCFieldSplitSetSchurFactType" 1818 /*@ 1819 PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain 1820 1821 Collective on PC 1822 1823 Input Parameters: 1824 + pc - the preconditioner context 1825 - ftype - which blocks of factorization to retain, PC_FIELDSPLIT_SCHUR_FACT_FULL is default 1826 1827 Options Database: 1828 . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> default is full 1829 1830 1831 Level: intermediate 1832 1833 Notes: 1834 The FULL factorization is 1835 1836 $ (A B) = (1 0) (A 0) (1 Ainv*B) 1837 $ (C D) (C*Ainv 1) (0 S) (0 1 ) 1838 1839 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, 1840 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). 1841 1842 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 1843 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 1844 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, 1845 the preconditioned operator has three distinct nonzero eigenvalues and minimal polynomial of degree at most 4, so KSPGMRES converges in at most 4 iterations. 1846 1847 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 1848 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). 1849 1850 References: 1851 Murphy, Golub, and Wathen, A note on preconditioning indefinite linear systems, SIAM J. Sci. Comput., 21 (2000) pp. 1969-1972. 1852 1853 Ipsen, A note on preconditioning nonsymmetric matrices, SIAM J. Sci. Comput., 23 (2001), pp. 1050-1051. 1854 1855 .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType 1856 @*/ 1857 PetscErrorCode PCFieldSplitSetSchurFactType(PC pc,PCFieldSplitSchurFactType ftype) 1858 { 1859 PetscErrorCode ierr; 1860 1861 PetscFunctionBegin; 1862 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1863 ierr = PetscTryMethod(pc,"PCFieldSplitSetSchurFactType_C",(PC,PCFieldSplitSchurFactType),(pc,ftype));CHKERRQ(ierr); 1864 PetscFunctionReturn(0); 1865 } 1866 1867 #undef __FUNCT__ 1868 #define __FUNCT__ "PCFieldSplitSetSchurFactType_FieldSplit" 1869 static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc,PCFieldSplitSchurFactType ftype) 1870 { 1871 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1872 1873 PetscFunctionBegin; 1874 jac->schurfactorization = ftype; 1875 PetscFunctionReturn(0); 1876 } 1877 1878 #undef __FUNCT__ 1879 #define __FUNCT__ "PCFieldSplitGetSchurBlocks" 1880 /*@C 1881 PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement 1882 1883 Collective on KSP 1884 1885 Input Parameter: 1886 . pc - the preconditioner context 1887 1888 Output Parameters: 1889 + A00 - the (0,0) block 1890 . A01 - the (0,1) block 1891 . A10 - the (1,0) block 1892 - A11 - the (1,1) block 1893 1894 Level: advanced 1895 1896 .seealso: PCFIELDSPLIT 1897 @*/ 1898 PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc,Mat *A00,Mat *A01,Mat *A10, Mat *A11) 1899 { 1900 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 1901 1902 PetscFunctionBegin; 1903 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1904 if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach."); 1905 if (A00) *A00 = jac->pmat[0]; 1906 if (A01) *A01 = jac->B; 1907 if (A10) *A10 = jac->C; 1908 if (A11) *A11 = jac->pmat[1]; 1909 PetscFunctionReturn(0); 1910 } 1911 1912 #undef __FUNCT__ 1913 #define __FUNCT__ "PCFieldSplitSetType_FieldSplit" 1914 static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc,PCCompositeType type) 1915 { 1916 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1917 PetscErrorCode ierr; 1918 1919 PetscFunctionBegin; 1920 jac->type = type; 1921 if (type == PC_COMPOSITE_SCHUR) { 1922 pc->ops->apply = PCApply_FieldSplit_Schur; 1923 pc->ops->view = PCView_FieldSplit_Schur; 1924 1925 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit_Schur);CHKERRQ(ierr); 1926 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurPre_C",PCFieldSplitSetSchurPre_FieldSplit);CHKERRQ(ierr); 1927 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSchurPre_C",PCFieldSplitGetSchurPre_FieldSplit);CHKERRQ(ierr); 1928 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",PCFieldSplitSetSchurFactType_FieldSplit);CHKERRQ(ierr); 1929 1930 } else { 1931 pc->ops->apply = PCApply_FieldSplit; 1932 pc->ops->view = PCView_FieldSplit; 1933 1934 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit);CHKERRQ(ierr); 1935 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurPre_C",0);CHKERRQ(ierr); 1936 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSchurPre_C",0);CHKERRQ(ierr); 1937 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",0);CHKERRQ(ierr); 1938 } 1939 PetscFunctionReturn(0); 1940 } 1941 1942 #undef __FUNCT__ 1943 #define __FUNCT__ "PCFieldSplitSetBlockSize_FieldSplit" 1944 static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc,PetscInt bs) 1945 { 1946 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 1947 1948 PetscFunctionBegin; 1949 if (bs < 1) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Blocksize must be positive, you gave %D",bs); 1950 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); 1951 jac->bs = bs; 1952 PetscFunctionReturn(0); 1953 } 1954 1955 #undef __FUNCT__ 1956 #define __FUNCT__ "PCFieldSplitSetType" 1957 /*@ 1958 PCFieldSplitSetType - Sets the type of fieldsplit preconditioner. 1959 1960 Collective on PC 1961 1962 Input Parameter: 1963 . pc - the preconditioner context 1964 . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR 1965 1966 Options Database Key: 1967 . -pc_fieldsplit_type <type: one of multiplicative, additive, symmetric_multiplicative, special, schur> - Sets fieldsplit preconditioner type 1968 1969 Level: Intermediate 1970 1971 .keywords: PC, set, type, composite preconditioner, additive, multiplicative 1972 1973 .seealso: PCCompositeSetType() 1974 1975 @*/ 1976 PetscErrorCode PCFieldSplitSetType(PC pc,PCCompositeType type) 1977 { 1978 PetscErrorCode ierr; 1979 1980 PetscFunctionBegin; 1981 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 1982 ierr = PetscTryMethod(pc,"PCFieldSplitSetType_C",(PC,PCCompositeType),(pc,type));CHKERRQ(ierr); 1983 PetscFunctionReturn(0); 1984 } 1985 1986 #undef __FUNCT__ 1987 #define __FUNCT__ "PCFieldSplitGetType" 1988 /*@ 1989 PCFieldSplitGetType - Gets the type of fieldsplit preconditioner. 1990 1991 Not collective 1992 1993 Input Parameter: 1994 . pc - the preconditioner context 1995 1996 Output Parameter: 1997 . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR 1998 1999 Level: Intermediate 2000 2001 .keywords: PC, set, type, composite preconditioner, additive, multiplicative 2002 .seealso: PCCompositeSetType() 2003 @*/ 2004 PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type) 2005 { 2006 PC_FieldSplit *jac = (PC_FieldSplit*) pc->data; 2007 2008 PetscFunctionBegin; 2009 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 2010 PetscValidIntPointer(type,2); 2011 *type = jac->type; 2012 PetscFunctionReturn(0); 2013 } 2014 2015 #undef __FUNCT__ 2016 #define __FUNCT__ "PCFieldSplitSetDMSplits" 2017 /*@ 2018 PCFieldSplitSetDMSplits - Flags whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible. 2019 2020 Logically Collective 2021 2022 Input Parameters: 2023 + pc - the preconditioner context 2024 - flg - boolean indicating whether to use field splits defined by the DM 2025 2026 Options Database Key: 2027 . -pc_fieldsplit_dm_splits 2028 2029 Level: Intermediate 2030 2031 .keywords: PC, DM, composite preconditioner, additive, multiplicative 2032 2033 .seealso: PCFieldSplitGetDMSplits() 2034 2035 @*/ 2036 PetscErrorCode PCFieldSplitSetDMSplits(PC pc,PetscBool flg) 2037 { 2038 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 2039 PetscBool isfs; 2040 PetscErrorCode ierr; 2041 2042 PetscFunctionBegin; 2043 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 2044 PetscValidLogicalCollectiveBool(pc,flg,2); 2045 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 2046 if (isfs) { 2047 jac->dm_splits = flg; 2048 } 2049 PetscFunctionReturn(0); 2050 } 2051 2052 2053 #undef __FUNCT__ 2054 #define __FUNCT__ "PCFieldSplitGetDMSplits" 2055 /*@ 2056 PCFieldSplitGetDMSplits - Returns flag indicating whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible. 2057 2058 Logically Collective 2059 2060 Input Parameter: 2061 . pc - the preconditioner context 2062 2063 Output Parameter: 2064 . flg - boolean indicating whether to use field splits defined by the DM 2065 2066 Level: Intermediate 2067 2068 .keywords: PC, DM, composite preconditioner, additive, multiplicative 2069 2070 .seealso: PCFieldSplitSetDMSplits() 2071 2072 @*/ 2073 PetscErrorCode PCFieldSplitGetDMSplits(PC pc,PetscBool* flg) 2074 { 2075 PC_FieldSplit *jac = (PC_FieldSplit*)pc->data; 2076 PetscBool isfs; 2077 PetscErrorCode ierr; 2078 2079 PetscFunctionBegin; 2080 PetscValidHeaderSpecific(pc,PC_CLASSID,1); 2081 PetscValidPointer(flg,2); 2082 ierr = PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);CHKERRQ(ierr); 2083 if (isfs) { 2084 if(flg) *flg = jac->dm_splits; 2085 } 2086 PetscFunctionReturn(0); 2087 } 2088 2089 /* -------------------------------------------------------------------------------------*/ 2090 /*MC 2091 PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual 2092 fields or groups of fields. See the users manual section "Solving Block Matrices" for more details. 2093 2094 To set options on the solvers for each block append -fieldsplit_ to all the PC 2095 options database keys. For example, -fieldsplit_pc_type ilu -fieldsplit_pc_factor_levels 1 2096 2097 To set the options on the solvers separate for each block call PCFieldSplitGetSubKSP() 2098 and set the options directly on the resulting KSP object 2099 2100 Level: intermediate 2101 2102 Options Database Keys: 2103 + -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the %d'th split 2104 . -pc_fieldsplit_default - automatically add any fields to additional splits that have not 2105 been supplied explicitly by -pc_fieldsplit_%d_fields 2106 . -pc_fieldsplit_block_size <bs> - size of block that defines fields (i.e. there are bs fields) 2107 . -pc_fieldsplit_type <additive,multiplicative,symmetric_multiplicative,schur> - type of relaxation or factorization splitting 2108 . -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is a11 2109 . -pc_fieldsplit_detect_saddle_point - automatically finds rows with zero or negative diagonal and uses Schur complement with no preconditioner as the solver 2110 2111 - Options prefix for inner solvers when using Schur complement preconditioner are -fieldsplit_0_ and -fieldsplit_1_ 2112 for all other solvers they are -fieldsplit_%d_ for the dth field, use -fieldsplit_ for all fields 2113 2114 Notes: 2115 Use PCFieldSplitSetFields() to set fields defined by "strided" entries and PCFieldSplitSetIS() 2116 to define a field by an arbitrary collection of entries. 2117 2118 If no fields are set the default is used. The fields are defined by entries strided by bs, 2119 beginning at 0 then 1, etc to bs-1. The block size can be set with PCFieldSplitSetBlockSize(), 2120 if this is not called the block size defaults to the blocksize of the second matrix passed 2121 to KSPSetOperators()/PCSetOperators(). 2122 2123 $ For the Schur complement preconditioner if J = ( A00 A01 ) 2124 $ ( A10 A11 ) 2125 $ the preconditioner using full factorization is 2126 $ ( I -ksp(A00) A01 ) ( inv(A00) 0 ) ( I 0 ) 2127 $ ( 0 I ) ( 0 ksp(S) ) ( -A10 ksp(A00) I ) 2128 where the action of inv(A00) is applied using the KSP solver with prefix -fieldsplit_0_. S is the Schur complement 2129 $ S = A11 - A10 ksp(A00) A01 2130 which is usually dense and not stored explicitly. The action of ksp(S) is computed using the KSP solver with prefix -fieldsplit_splitname_ (where splitname was given 2131 in providing the SECOND split or 1 if not give). For PCFieldSplitGetKSP() when field number is 0, 2132 it returns the KSP associated with -fieldsplit_0_ while field number 1 gives -fieldsplit_1_ KSP. By default 2133 A11 is used to construct a preconditioner for S, use PCFieldSplitSetSchurPre() to turn on or off this 2134 option. You can use the preconditioner PCLSC to precondition the Schur complement with -fieldsplit_1_pc_type lsc. 2135 When option -fieldsplit_schur_precondition selfp is given, an approximation to S is assembled -- 2136 Sp = A11 - A10 inv(diag(A00)) A01, which has type AIJ and can be used with a variety of preconditioners 2137 (e.g., -fieldsplit_1_pc_type asm). 2138 The factorization type is set using -pc_fieldsplit_schur_fact_type <diag, lower, upper, full>. The full is shown above, 2139 diag gives 2140 $ ( inv(A00) 0 ) 2141 $ ( 0 -ksp(S) ) 2142 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 2143 $ ( A00 0 ) 2144 $ ( A10 S ) 2145 where the inverses of A00 and S are applied using KSPs. The upper factorization is the inverse of 2146 $ ( A00 A01 ) 2147 $ ( 0 S ) 2148 where again the inverses of A00 and S are applied using KSPs. 2149 2150 If only one set of indices (one IS) is provided with PCFieldSplitSetIS() then the complement of that IS 2151 is used automatically for a second block. 2152 2153 The fieldsplit preconditioner cannot currently be used with the BAIJ or SBAIJ data formats if the blocksize is larger than 1. 2154 Generally it should be used with the AIJ format. 2155 2156 The forms of these preconditioners are closely related if not identical to forms derived as "Distributive Iterations", see, 2157 for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling. Note that one can also use PCFIELDSPLIT 2158 inside a smoother resulting in "Distributive Smoothers". 2159 2160 Concepts: physics based preconditioners, block preconditioners 2161 2162 There is a nice discussion of block preconditioners in 2163 2164 [El08] A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations 2165 Howard Elman, V.E. Howle, John Shadid, Robert Shuttleworth, Ray Tuminaro, Journal of Computational Physics 227 (2008) 1790--1808 2166 http://chess.cs.umd.edu/~elman/papers/tax.pdf 2167 2168 .seealso: PCCreate(), PCSetType(), PCType (for list of available types), PC, Block_Preconditioners, PCLSC, 2169 PCFieldSplitGetSubKSP(), PCFieldSplitSetFields(), PCFieldSplitSetType(), PCFieldSplitSetIS(), PCFieldSplitSetSchurPre() 2170 M*/ 2171 2172 #undef __FUNCT__ 2173 #define __FUNCT__ "PCCreate_FieldSplit" 2174 PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc) 2175 { 2176 PetscErrorCode ierr; 2177 PC_FieldSplit *jac; 2178 2179 PetscFunctionBegin; 2180 ierr = PetscNewLog(pc,&jac);CHKERRQ(ierr); 2181 2182 jac->bs = -1; 2183 jac->nsplits = 0; 2184 jac->type = PC_COMPOSITE_MULTIPLICATIVE; 2185 jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */ 2186 jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL; 2187 jac->dm_splits = PETSC_TRUE; 2188 2189 pc->data = (void*)jac; 2190 2191 pc->ops->apply = PCApply_FieldSplit; 2192 pc->ops->applytranspose = PCApplyTranspose_FieldSplit; 2193 pc->ops->setup = PCSetUp_FieldSplit; 2194 pc->ops->reset = PCReset_FieldSplit; 2195 pc->ops->destroy = PCDestroy_FieldSplit; 2196 pc->ops->setfromoptions = PCSetFromOptions_FieldSplit; 2197 pc->ops->view = PCView_FieldSplit; 2198 pc->ops->applyrichardson = 0; 2199 2200 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit);CHKERRQ(ierr); 2201 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C",PCFieldSplitSetFields_FieldSplit);CHKERRQ(ierr); 2202 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C",PCFieldSplitSetIS_FieldSplit);CHKERRQ(ierr); 2203 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C",PCFieldSplitSetType_FieldSplit);CHKERRQ(ierr); 2204 ierr = PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C",PCFieldSplitSetBlockSize_FieldSplit);CHKERRQ(ierr); 2205 PetscFunctionReturn(0); 2206 } 2207 2208 2209 2210