1 #include <petsc/private/pcimpl.h> /*I "petscpc.h" I*/ 2 #include <petsc/private/kspimpl.h> /* This is needed to provide the appropriate PETSC_EXTERN for KSP_Solve_FS ....*/ 3 #include <petscdm.h> 4 5 const char *const PCFieldSplitSchurPreTypes[] = {"SELF", "SELFP", "A11", "USER", "FULL", "PCFieldSplitSchurPreType", "PC_FIELDSPLIT_SCHUR_PRE_", NULL}; 6 const char *const PCFieldSplitSchurFactTypes[] = {"DIAG", "LOWER", "UPPER", "FULL", "PCFieldSplitSchurFactType", "PC_FIELDSPLIT_SCHUR_FACT_", NULL}; 7 8 PetscLogEvent KSP_Solve_FS_0, KSP_Solve_FS_1, KSP_Solve_FS_S, KSP_Solve_FS_U, KSP_Solve_FS_L, KSP_Solve_FS_2, KSP_Solve_FS_3, KSP_Solve_FS_4; 9 10 typedef struct _PC_FieldSplitLink *PC_FieldSplitLink; 11 struct _PC_FieldSplitLink { 12 KSP ksp; 13 Vec x, y, z; 14 char *splitname; 15 PetscInt nfields; 16 PetscInt *fields, *fields_col; 17 VecScatter sctx; 18 IS is, is_col; 19 PC_FieldSplitLink next, previous; 20 PetscLogEvent event; 21 22 /* Used only when setting coordinates with PCSetCoordinates */ 23 PetscInt dim; 24 PetscInt ndofs; 25 PetscReal *coords; 26 }; 27 28 typedef struct { 29 PCCompositeType type; 30 PetscBool defaultsplit; /* Flag for a system with a set of 'k' scalar fields with the same layout (and bs = k) */ 31 PetscBool splitdefined; /* Flag is set after the splits have been defined, to prevent more splits from being added */ 32 PetscInt bs; /* Block size for IS and Mat structures */ 33 PetscInt nsplits; /* Number of field divisions defined */ 34 Vec *x, *y, w1, w2; 35 Mat *mat; /* The diagonal block for each split */ 36 Mat *pmat; /* The preconditioning diagonal block for each split */ 37 Mat *Afield; /* The rows of the matrix associated with each split */ 38 PetscBool issetup; 39 40 /* Only used when Schur complement preconditioning is used */ 41 Mat B; /* The (0,1) block */ 42 Mat C; /* The (1,0) block */ 43 Mat schur; /* The Schur complement S = A11 - A10 A00^{-1} A01, the KSP here, kspinner, is H_1 in [El08] */ 44 Mat schurp; /* Assembled approximation to S built by MatSchurComplement to be used as a preconditioning matrix when solving with S */ 45 Mat schur_user; /* User-provided preconditioning matrix for the Schur complement */ 46 PCFieldSplitSchurPreType schurpre; /* Determines which preconditioning matrix is used for the Schur complement */ 47 PCFieldSplitSchurFactType schurfactorization; 48 KSP kspschur; /* The solver for S */ 49 KSP kspupper; /* The solver for A in the upper diagonal part of the factorization (H_2 in [El08]) */ 50 PetscScalar schurscale; /* Scaling factor for the Schur complement solution with DIAG factorization */ 51 52 /* Only used when Golub-Kahan bidiagonalization preconditioning is used */ 53 Mat H; /* The modified matrix H = A00 + nu*A01*A01' */ 54 PetscReal gkbtol; /* Stopping tolerance for lower bound estimate */ 55 PetscInt gkbdelay; /* The delay window for the stopping criterion */ 56 PetscReal gkbnu; /* Parameter for augmented Lagrangian H = A + nu*A01*A01' */ 57 PetscInt gkbmaxit; /* Maximum number of iterations for outer loop */ 58 PetscBool gkbmonitor; /* Monitor for gkb iterations and the lower bound error */ 59 PetscViewer gkbviewer; /* Viewer context for gkbmonitor */ 60 Vec u, v, d, Hu; /* Work vectors for the GKB algorithm */ 61 PetscScalar *vecz; /* Contains intermediate values, eg for lower bound */ 62 63 PC_FieldSplitLink head; 64 PetscBool isrestrict; /* indicates PCFieldSplitRestrictIS() has been last called on this object, hack */ 65 PetscBool suboptionsset; /* Indicates that the KSPSetFromOptions() has been called on the sub-KSPs */ 66 PetscBool dm_splits; /* Whether to use DMCreateFieldDecomposition() whenever possible */ 67 PetscBool diag_use_amat; /* Whether to extract diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */ 68 PetscBool offdiag_use_amat; /* Whether to extract off-diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */ 69 PetscBool detect; /* Whether to form 2-way split by finding zero diagonal entries */ 70 PetscBool coordinates_set; /* Whether PCSetCoordinates has been called */ 71 } PC_FieldSplit; 72 73 /* 74 Note: 75 there is no particular reason that pmat, x, and y are stored as arrays in PC_FieldSplit instead of 76 inside PC_FieldSplitLink, just historical. If you want to be able to add new fields after already using the 77 PC you could change this. 78 */ 79 80 /* This helper is so that setting a user-provided preconditioning matrix is orthogonal to choosing to use it. This way the 81 * application-provided FormJacobian can provide this matrix without interfering with the user's (command-line) choices. */ 82 static Mat FieldSplitSchurPre(PC_FieldSplit *jac) 83 { 84 switch (jac->schurpre) { 85 case PC_FIELDSPLIT_SCHUR_PRE_SELF: 86 return jac->schur; 87 case PC_FIELDSPLIT_SCHUR_PRE_SELFP: 88 return jac->schurp; 89 case PC_FIELDSPLIT_SCHUR_PRE_A11: 90 return jac->pmat[1]; 91 case PC_FIELDSPLIT_SCHUR_PRE_FULL: /* We calculate this and store it in schur_user */ 92 case PC_FIELDSPLIT_SCHUR_PRE_USER: /* Use a user-provided matrix if it is given, otherwise diagonal block */ 93 default: 94 return jac->schur_user ? jac->schur_user : jac->pmat[1]; 95 } 96 } 97 98 #include <petscdraw.h> 99 static PetscErrorCode PCView_FieldSplit(PC pc, PetscViewer viewer) 100 { 101 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 102 PetscBool iascii, isdraw; 103 PetscInt i, j; 104 PC_FieldSplitLink ilink = jac->head; 105 106 PetscFunctionBegin; 107 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii)); 108 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw)); 109 if (iascii) { 110 if (jac->bs > 0) { 111 PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT ", blocksize = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits, jac->bs)); 112 } else { 113 PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits)); 114 } 115 if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n")); 116 if (jac->diag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for diagonal blocks\n")); 117 if (jac->offdiag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for off-diagonal blocks\n")); 118 PetscCall(PetscViewerASCIIPrintf(viewer, " Solver info for each split is in the following KSP objects:\n")); 119 for (i = 0; i < jac->nsplits; i++) { 120 if (ilink->fields) { 121 PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Fields ", i)); 122 PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE)); 123 for (j = 0; j < ilink->nfields; j++) { 124 if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ",")); 125 PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j])); 126 } 127 PetscCall(PetscViewerASCIIPrintf(viewer, "\n")); 128 PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE)); 129 } else { 130 PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Defined by IS\n", i)); 131 } 132 PetscCall(KSPView(ilink->ksp, viewer)); 133 ilink = ilink->next; 134 } 135 } 136 137 if (isdraw) { 138 PetscDraw draw; 139 PetscReal x, y, w, wd; 140 141 PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw)); 142 PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y)); 143 w = 2 * PetscMin(1.0 - x, x); 144 wd = w / (jac->nsplits + 1); 145 x = x - wd * (jac->nsplits - 1) / 2.0; 146 for (i = 0; i < jac->nsplits; i++) { 147 PetscCall(PetscDrawPushCurrentPoint(draw, x, y)); 148 PetscCall(KSPView(ilink->ksp, viewer)); 149 PetscCall(PetscDrawPopCurrentPoint(draw)); 150 x += wd; 151 ilink = ilink->next; 152 } 153 } 154 PetscFunctionReturn(PETSC_SUCCESS); 155 } 156 157 static PetscErrorCode PCView_FieldSplit_Schur(PC pc, PetscViewer viewer) 158 { 159 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 160 PetscBool iascii, isdraw; 161 PetscInt i, j; 162 PC_FieldSplitLink ilink = jac->head; 163 MatSchurComplementAinvType atype; 164 165 PetscFunctionBegin; 166 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii)); 167 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw)); 168 if (iascii) { 169 if (jac->bs > 0) { 170 PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with Schur preconditioner, blocksize = %" PetscInt_FMT ", factorization %s\n", jac->bs, PCFieldSplitSchurFactTypes[jac->schurfactorization])); 171 } else { 172 PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with Schur preconditioner, factorization %s\n", PCFieldSplitSchurFactTypes[jac->schurfactorization])); 173 } 174 if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n")); 175 switch (jac->schurpre) { 176 case PC_FIELDSPLIT_SCHUR_PRE_SELF: 177 PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from S itself\n")); 178 break; 179 case PC_FIELDSPLIT_SCHUR_PRE_SELFP: 180 if (jac->schur) { 181 PetscCall(MatSchurComplementGetAinvType(jac->schur, &atype)); 182 PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from Sp, an assembled approximation to S, which uses A00's %sinverse\n", atype == MAT_SCHUR_COMPLEMENT_AINV_DIAG ? "diagonal's " : (atype == MAT_SCHUR_COMPLEMENT_AINV_BLOCK_DIAG ? "block diagonal's " : (atype == MAT_SCHUR_COMPLEMENT_AINV_FULL ? "full " : "lumped diagonal's ")))); 183 } 184 break; 185 case PC_FIELDSPLIT_SCHUR_PRE_A11: 186 PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from A11\n")); 187 break; 188 case PC_FIELDSPLIT_SCHUR_PRE_FULL: 189 PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from the exact Schur complement\n")); 190 break; 191 case PC_FIELDSPLIT_SCHUR_PRE_USER: 192 if (jac->schur_user) { 193 PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from user provided matrix\n")); 194 } else { 195 PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from A11\n")); 196 } 197 break; 198 default: 199 SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Invalid Schur preconditioning type: %d", jac->schurpre); 200 } 201 PetscCall(PetscViewerASCIIPrintf(viewer, " Split info:\n")); 202 PetscCall(PetscViewerASCIIPushTab(viewer)); 203 for (i = 0; i < jac->nsplits; i++) { 204 if (ilink->fields) { 205 PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Fields ", i)); 206 PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE)); 207 for (j = 0; j < ilink->nfields; j++) { 208 if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ",")); 209 PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j])); 210 } 211 PetscCall(PetscViewerASCIIPrintf(viewer, "\n")); 212 PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE)); 213 } else { 214 PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Defined by IS\n", i)); 215 } 216 ilink = ilink->next; 217 } 218 PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for A00 block\n")); 219 PetscCall(PetscViewerASCIIPushTab(viewer)); 220 if (jac->head) { 221 PetscCall(KSPView(jac->head->ksp, viewer)); 222 } else PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n")); 223 PetscCall(PetscViewerASCIIPopTab(viewer)); 224 if (jac->head && jac->kspupper != jac->head->ksp) { 225 PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for upper A00 in upper triangular factor\n")); 226 PetscCall(PetscViewerASCIIPushTab(viewer)); 227 if (jac->kspupper) PetscCall(KSPView(jac->kspupper, viewer)); 228 else PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n")); 229 PetscCall(PetscViewerASCIIPopTab(viewer)); 230 } 231 PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for S = A11 - A10 inv(A00) A01\n")); 232 PetscCall(PetscViewerASCIIPushTab(viewer)); 233 if (jac->kspschur) { 234 PetscCall(KSPView(jac->kspschur, viewer)); 235 } else { 236 PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n")); 237 } 238 PetscCall(PetscViewerASCIIPopTab(viewer)); 239 PetscCall(PetscViewerASCIIPopTab(viewer)); 240 } else if (isdraw && jac->head) { 241 PetscDraw draw; 242 PetscReal x, y, w, wd, h; 243 PetscInt cnt = 2; 244 char str[32]; 245 246 PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw)); 247 PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y)); 248 if (jac->kspupper != jac->head->ksp) cnt++; 249 w = 2 * PetscMin(1.0 - x, x); 250 wd = w / (cnt + 1); 251 252 PetscCall(PetscSNPrintf(str, 32, "Schur fact. %s", PCFieldSplitSchurFactTypes[jac->schurfactorization])); 253 PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_RED, PETSC_DRAW_BLACK, str, NULL, &h)); 254 y -= h; 255 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_USER && !jac->schur_user) { 256 PetscCall(PetscSNPrintf(str, 32, "Prec. for Schur from %s", PCFieldSplitSchurPreTypes[PC_FIELDSPLIT_SCHUR_PRE_A11])); 257 } else { 258 PetscCall(PetscSNPrintf(str, 32, "Prec. for Schur from %s", PCFieldSplitSchurPreTypes[jac->schurpre])); 259 } 260 PetscCall(PetscDrawStringBoxed(draw, x + wd * (cnt - 1) / 2.0, y, PETSC_DRAW_RED, PETSC_DRAW_BLACK, str, NULL, &h)); 261 y -= h; 262 x = x - wd * (cnt - 1) / 2.0; 263 264 PetscCall(PetscDrawPushCurrentPoint(draw, x, y)); 265 PetscCall(KSPView(jac->head->ksp, viewer)); 266 PetscCall(PetscDrawPopCurrentPoint(draw)); 267 if (jac->kspupper != jac->head->ksp) { 268 x += wd; 269 PetscCall(PetscDrawPushCurrentPoint(draw, x, y)); 270 PetscCall(KSPView(jac->kspupper, viewer)); 271 PetscCall(PetscDrawPopCurrentPoint(draw)); 272 } 273 x += wd; 274 PetscCall(PetscDrawPushCurrentPoint(draw, x, y)); 275 PetscCall(KSPView(jac->kspschur, viewer)); 276 PetscCall(PetscDrawPopCurrentPoint(draw)); 277 } 278 PetscFunctionReturn(PETSC_SUCCESS); 279 } 280 281 static PetscErrorCode PCView_FieldSplit_GKB(PC pc, PetscViewer viewer) 282 { 283 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 284 PetscBool iascii, isdraw; 285 PetscInt i, j; 286 PC_FieldSplitLink ilink = jac->head; 287 288 PetscFunctionBegin; 289 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii)); 290 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw)); 291 if (iascii) { 292 if (jac->bs > 0) { 293 PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT ", blocksize = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits, jac->bs)); 294 } else { 295 PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits)); 296 } 297 if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n")); 298 if (jac->diag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for diagonal blocks\n")); 299 if (jac->offdiag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for off-diagonal blocks\n")); 300 301 PetscCall(PetscViewerASCIIPrintf(viewer, " Stopping tolerance=%.1e, delay in error estimate=%" PetscInt_FMT ", maximum iterations=%" PetscInt_FMT "\n", (double)jac->gkbtol, jac->gkbdelay, jac->gkbmaxit)); 302 PetscCall(PetscViewerASCIIPrintf(viewer, " Solver info for H = A00 + nu*A01*A01' matrix:\n")); 303 PetscCall(PetscViewerASCIIPushTab(viewer)); 304 305 if (ilink->fields) { 306 PetscCall(PetscViewerASCIIPrintf(viewer, "Split number 0 Fields ")); 307 PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE)); 308 for (j = 0; j < ilink->nfields; j++) { 309 if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ",")); 310 PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j])); 311 } 312 PetscCall(PetscViewerASCIIPrintf(viewer, "\n")); 313 PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE)); 314 } else { 315 PetscCall(PetscViewerASCIIPrintf(viewer, "Split number 0 Defined by IS\n")); 316 } 317 PetscCall(KSPView(ilink->ksp, viewer)); 318 319 PetscCall(PetscViewerASCIIPopTab(viewer)); 320 } 321 322 if (isdraw) { 323 PetscDraw draw; 324 PetscReal x, y, w, wd; 325 326 PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw)); 327 PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y)); 328 w = 2 * PetscMin(1.0 - x, x); 329 wd = w / (jac->nsplits + 1); 330 x = x - wd * (jac->nsplits - 1) / 2.0; 331 for (i = 0; i < jac->nsplits; i++) { 332 PetscCall(PetscDrawPushCurrentPoint(draw, x, y)); 333 PetscCall(KSPView(ilink->ksp, viewer)); 334 PetscCall(PetscDrawPopCurrentPoint(draw)); 335 x += wd; 336 ilink = ilink->next; 337 } 338 } 339 PetscFunctionReturn(PETSC_SUCCESS); 340 } 341 342 /* Precondition: jac->bs is set to a meaningful value */ 343 static PetscErrorCode PCFieldSplitSetRuntimeSplits_Private(PC pc) 344 { 345 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 346 PetscInt i, nfields, *ifields, nfields_col, *ifields_col; 347 PetscBool flg, flg_col; 348 char optionname[128], splitname[8], optionname_col[128]; 349 350 PetscFunctionBegin; 351 PetscCall(PetscMalloc1(jac->bs, &ifields)); 352 PetscCall(PetscMalloc1(jac->bs, &ifields_col)); 353 for (i = 0, flg = PETSC_TRUE;; i++) { 354 PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i)); 355 PetscCall(PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%" PetscInt_FMT "_fields", i)); 356 PetscCall(PetscSNPrintf(optionname_col, sizeof(optionname_col), "-pc_fieldsplit_%" PetscInt_FMT "_fields_col", i)); 357 nfields = jac->bs; 358 nfields_col = jac->bs; 359 PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname, ifields, &nfields, &flg)); 360 PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname_col, ifields_col, &nfields_col, &flg_col)); 361 if (!flg) break; 362 else if (flg && !flg_col) { 363 PetscCheck(nfields, PETSC_COMM_SELF, PETSC_ERR_USER, "Cannot list zero fields"); 364 PetscCall(PCFieldSplitSetFields(pc, splitname, nfields, ifields, ifields)); 365 } else { 366 PetscCheck(nfields && nfields_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Cannot list zero fields"); 367 PetscCheck(nfields == nfields_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Number of row and column fields must match"); 368 PetscCall(PCFieldSplitSetFields(pc, splitname, nfields, ifields, ifields_col)); 369 } 370 } 371 if (i > 0) { 372 /* Makes command-line setting of splits take precedence over setting them in code. 373 Otherwise subsequent calls to PCFieldSplitSetIS() or PCFieldSplitSetFields() would 374 create new splits, which would probably not be what the user wanted. */ 375 jac->splitdefined = PETSC_TRUE; 376 } 377 PetscCall(PetscFree(ifields)); 378 PetscCall(PetscFree(ifields_col)); 379 PetscFunctionReturn(PETSC_SUCCESS); 380 } 381 382 static PetscErrorCode PCFieldSplitSetDefaults(PC pc) 383 { 384 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 385 PC_FieldSplitLink ilink = jac->head; 386 PetscBool fieldsplit_default = PETSC_FALSE, coupling = PETSC_FALSE; 387 PetscInt i; 388 389 PetscFunctionBegin; 390 /* 391 Kinda messy, but at least this now uses DMCreateFieldDecomposition(). 392 Should probably be rewritten. 393 */ 394 if (!ilink) { 395 PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_detect_coupling", &coupling, NULL)); 396 if (pc->dm && jac->dm_splits && !jac->detect && !coupling) { 397 PetscInt numFields, f, i, j; 398 char **fieldNames; 399 IS *fields; 400 DM *dms; 401 DM subdm[128]; 402 PetscBool flg; 403 404 PetscCall(DMCreateFieldDecomposition(pc->dm, &numFields, &fieldNames, &fields, &dms)); 405 /* Allow the user to prescribe the splits */ 406 for (i = 0, flg = PETSC_TRUE;; i++) { 407 PetscInt ifields[128]; 408 IS compField; 409 char optionname[128], splitname[8]; 410 PetscInt nfields = numFields; 411 412 PetscCall(PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%" PetscInt_FMT "_fields", i)); 413 PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname, ifields, &nfields, &flg)); 414 if (!flg) break; 415 PetscCheck(numFields <= 128, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Cannot currently support %" PetscInt_FMT " > 128 fields", numFields); 416 PetscCall(DMCreateSubDM(pc->dm, nfields, ifields, &compField, &subdm[i])); 417 if (nfields == 1) { 418 PetscCall(PCFieldSplitSetIS(pc, fieldNames[ifields[0]], compField)); 419 } else { 420 PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i)); 421 PetscCall(PCFieldSplitSetIS(pc, splitname, compField)); 422 } 423 PetscCall(ISDestroy(&compField)); 424 for (j = 0; j < nfields; ++j) { 425 f = ifields[j]; 426 PetscCall(PetscFree(fieldNames[f])); 427 PetscCall(ISDestroy(&fields[f])); 428 } 429 } 430 if (i == 0) { 431 for (f = 0; f < numFields; ++f) { 432 PetscCall(PCFieldSplitSetIS(pc, fieldNames[f], fields[f])); 433 PetscCall(PetscFree(fieldNames[f])); 434 PetscCall(ISDestroy(&fields[f])); 435 } 436 } else { 437 for (j = 0; j < numFields; j++) PetscCall(DMDestroy(dms + j)); 438 PetscCall(PetscFree(dms)); 439 PetscCall(PetscMalloc1(i, &dms)); 440 for (j = 0; j < i; ++j) dms[j] = subdm[j]; 441 } 442 PetscCall(PetscFree(fieldNames)); 443 PetscCall(PetscFree(fields)); 444 if (dms) { 445 PetscCall(PetscInfo(pc, "Setting up physics based fieldsplit preconditioner using the embedded DM\n")); 446 for (ilink = jac->head, i = 0; ilink; ilink = ilink->next, ++i) { 447 const char *prefix; 448 PetscCall(PetscObjectGetOptionsPrefix((PetscObject)(ilink->ksp), &prefix)); 449 PetscCall(PetscObjectSetOptionsPrefix((PetscObject)(dms[i]), prefix)); 450 PetscCall(KSPSetDM(ilink->ksp, dms[i])); 451 PetscCall(KSPSetDMActive(ilink->ksp, PETSC_FALSE)); 452 { 453 PetscErrorCode (*func)(KSP, Mat, Mat, void *); 454 void *ctx; 455 456 PetscCall(DMKSPGetComputeOperators(pc->dm, &func, &ctx)); 457 PetscCall(DMKSPSetComputeOperators(dms[i], func, ctx)); 458 } 459 PetscCall(PetscObjectIncrementTabLevel((PetscObject)dms[i], (PetscObject)ilink->ksp, 0)); 460 PetscCall(DMDestroy(&dms[i])); 461 } 462 PetscCall(PetscFree(dms)); 463 } 464 } else { 465 if (jac->bs <= 0) { 466 if (pc->pmat) { 467 PetscCall(MatGetBlockSize(pc->pmat, &jac->bs)); 468 } else jac->bs = 1; 469 } 470 471 if (jac->detect) { 472 IS zerodiags, rest; 473 PetscInt nmin, nmax; 474 475 PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax)); 476 if (jac->diag_use_amat) { 477 PetscCall(MatFindZeroDiagonals(pc->mat, &zerodiags)); 478 } else { 479 PetscCall(MatFindZeroDiagonals(pc->pmat, &zerodiags)); 480 } 481 PetscCall(ISComplement(zerodiags, nmin, nmax, &rest)); 482 PetscCall(PCFieldSplitSetIS(pc, "0", rest)); 483 PetscCall(PCFieldSplitSetIS(pc, "1", zerodiags)); 484 PetscCall(ISDestroy(&zerodiags)); 485 PetscCall(ISDestroy(&rest)); 486 } else if (coupling) { 487 IS coupling, rest; 488 PetscInt nmin, nmax; 489 490 PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax)); 491 if (jac->offdiag_use_amat) { 492 PetscCall(MatFindOffBlockDiagonalEntries(pc->mat, &coupling)); 493 } else { 494 PetscCall(MatFindOffBlockDiagonalEntries(pc->pmat, &coupling)); 495 } 496 PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc->mat), nmax - nmin, nmin, 1, &rest)); 497 PetscCall(ISSetIdentity(rest)); 498 PetscCall(PCFieldSplitSetIS(pc, "0", rest)); 499 PetscCall(PCFieldSplitSetIS(pc, "1", coupling)); 500 PetscCall(ISDestroy(&coupling)); 501 PetscCall(ISDestroy(&rest)); 502 } else { 503 PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_default", &fieldsplit_default, NULL)); 504 if (!fieldsplit_default) { 505 /* Allow user to set fields from command line, if bs was known at the time of PCSetFromOptions_FieldSplit() 506 then it is set there. This is not ideal because we should only have options set in XXSetFromOptions(). */ 507 PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc)); 508 if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n")); 509 } 510 if ((fieldsplit_default || !jac->splitdefined) && !jac->isrestrict) { 511 Mat M = pc->pmat; 512 PetscBool isnest; 513 514 PetscCall(PetscInfo(pc, "Using default splitting of fields\n")); 515 PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &isnest)); 516 if (!isnest) { 517 M = pc->mat; 518 PetscCall(PetscObjectTypeCompare((PetscObject)pc->mat, MATNEST, &isnest)); 519 } 520 if (isnest) { 521 IS *fields; 522 PetscInt nf; 523 524 PetscCall(MatNestGetSize(M, &nf, NULL)); 525 PetscCall(PetscMalloc1(nf, &fields)); 526 PetscCall(MatNestGetISs(M, fields, NULL)); 527 for (i = 0; i < nf; i++) PetscCall(PCFieldSplitSetIS(pc, NULL, fields[i])); 528 PetscCall(PetscFree(fields)); 529 } else { 530 for (i = 0; i < jac->bs; i++) { 531 char splitname[8]; 532 PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i)); 533 PetscCall(PCFieldSplitSetFields(pc, splitname, 1, &i, &i)); 534 } 535 jac->defaultsplit = PETSC_TRUE; 536 } 537 } 538 } 539 } 540 } else if (jac->nsplits == 1) { 541 IS is2; 542 PetscInt nmin, nmax; 543 544 PetscCheck(ilink->is, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Must provide at least two sets of fields to PCFieldSplit()"); 545 PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax)); 546 PetscCall(ISComplement(ilink->is, nmin, nmax, &is2)); 547 PetscCall(PCFieldSplitSetIS(pc, "1", is2)); 548 PetscCall(ISDestroy(&is2)); 549 } 550 551 PetscCheck(jac->nsplits >= 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unhandled case, must have at least two fields, not %" PetscInt_FMT, jac->nsplits); 552 PetscFunctionReturn(PETSC_SUCCESS); 553 } 554 555 static PetscErrorCode MatGolubKahanComputeExplicitOperator(Mat A, Mat B, Mat C, Mat *H, PetscReal gkbnu) 556 { 557 Mat BT, T; 558 PetscReal nrmT, nrmB; 559 560 PetscFunctionBegin; 561 PetscCall(MatHermitianTranspose(C, MAT_INITIAL_MATRIX, &T)); /* Test if augmented matrix is symmetric */ 562 PetscCall(MatAXPY(T, -1.0, B, DIFFERENT_NONZERO_PATTERN)); 563 PetscCall(MatNorm(T, NORM_1, &nrmT)); 564 PetscCall(MatNorm(B, NORM_1, &nrmB)); 565 PetscCheck(nrmB <= 0 || nrmT / nrmB < PETSC_SMALL, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Matrix is not symmetric/hermitian, GKB is not applicable."); 566 567 /* Compute augmented Lagrangian matrix H = A00 + nu*A01*A01'. This corresponds to */ 568 /* setting N := 1/nu*I in [Ar13]. */ 569 PetscCall(MatHermitianTranspose(B, MAT_INITIAL_MATRIX, &BT)); 570 PetscCall(MatMatMult(B, BT, MAT_INITIAL_MATRIX, PETSC_DEFAULT, H)); /* H = A01*A01' */ 571 PetscCall(MatAYPX(*H, gkbnu, A, DIFFERENT_NONZERO_PATTERN)); /* H = A00 + nu*A01*A01' */ 572 573 PetscCall(MatDestroy(&BT)); 574 PetscCall(MatDestroy(&T)); 575 PetscFunctionReturn(PETSC_SUCCESS); 576 } 577 578 PETSC_EXTERN PetscErrorCode PetscOptionsFindPairPrefix_Private(PetscOptions, const char pre[], const char name[], const char *option[], const char *value[], PetscBool *flg); 579 580 static PetscErrorCode PCSetUp_FieldSplit(PC pc) 581 { 582 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 583 PC_FieldSplitLink ilink; 584 PetscInt i, nsplit; 585 PetscBool sorted, sorted_col; 586 587 PetscFunctionBegin; 588 pc->failedreason = PC_NOERROR; 589 PetscCall(PCFieldSplitSetDefaults(pc)); 590 nsplit = jac->nsplits; 591 ilink = jac->head; 592 593 /* get the matrices for each split */ 594 if (!jac->issetup) { 595 PetscInt rstart, rend, nslots, bs; 596 597 jac->issetup = PETSC_TRUE; 598 599 /* This is done here instead of in PCFieldSplitSetFields() because may not have matrix at that point */ 600 if (jac->defaultsplit || !ilink->is) { 601 if (jac->bs <= 0) jac->bs = nsplit; 602 } 603 604 /* MatCreateSubMatrix() for [S]BAIJ matrices can only work if the indices include entire blocks of the matrix */ 605 PetscCall(MatGetBlockSize(pc->pmat, &bs)); 606 if (bs > 1 && (jac->bs <= bs || jac->bs % bs)) { 607 PetscBool blk; 608 609 PetscCall(PetscObjectTypeCompareAny((PetscObject)pc->pmat, &blk, MATBAIJ, MATSBAIJ, MATSEQBAIJ, MATSEQSBAIJ, MATMPIBAIJ, MATMPISBAIJ, NULL)); 610 PetscCheck(!blk, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Cannot use MATBAIJ with PCFIELDSPLIT and currently set matrix and PC blocksizes"); 611 } 612 613 bs = jac->bs; 614 PetscCall(MatGetOwnershipRange(pc->pmat, &rstart, &rend)); 615 nslots = (rend - rstart) / bs; 616 for (i = 0; i < nsplit; i++) { 617 if (jac->defaultsplit) { 618 PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + i, nsplit, &ilink->is)); 619 PetscCall(ISDuplicate(ilink->is, &ilink->is_col)); 620 } else if (!ilink->is) { 621 if (ilink->nfields > 1) { 622 PetscInt *ii, *jj, j, k, nfields = ilink->nfields, *fields = ilink->fields, *fields_col = ilink->fields_col; 623 PetscCall(PetscMalloc1(ilink->nfields * nslots, &ii)); 624 PetscCall(PetscMalloc1(ilink->nfields * nslots, &jj)); 625 for (j = 0; j < nslots; j++) { 626 for (k = 0; k < nfields; k++) { 627 ii[nfields * j + k] = rstart + bs * j + fields[k]; 628 jj[nfields * j + k] = rstart + bs * j + fields_col[k]; 629 } 630 } 631 PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, ii, PETSC_OWN_POINTER, &ilink->is)); 632 PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, jj, PETSC_OWN_POINTER, &ilink->is_col)); 633 PetscCall(ISSetBlockSize(ilink->is, nfields)); 634 PetscCall(ISSetBlockSize(ilink->is_col, nfields)); 635 } else { 636 PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields[0], bs, &ilink->is)); 637 PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields_col[0], bs, &ilink->is_col)); 638 } 639 } 640 PetscCall(ISSorted(ilink->is, &sorted)); 641 if (ilink->is_col) PetscCall(ISSorted(ilink->is_col, &sorted_col)); 642 PetscCheck(sorted && sorted_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Fields must be sorted when creating split"); 643 ilink = ilink->next; 644 } 645 } 646 647 ilink = jac->head; 648 if (!jac->pmat) { 649 Vec xtmp; 650 651 PetscCall(MatCreateVecs(pc->pmat, &xtmp, NULL)); 652 PetscCall(PetscMalloc1(nsplit, &jac->pmat)); 653 PetscCall(PetscMalloc2(nsplit, &jac->x, nsplit, &jac->y)); 654 for (i = 0; i < nsplit; i++) { 655 MatNullSpace sp; 656 657 /* Check for preconditioning matrix attached to IS */ 658 PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&jac->pmat[i])); 659 if (jac->pmat[i]) { 660 PetscCall(PetscObjectReference((PetscObject)jac->pmat[i])); 661 if (jac->type == PC_COMPOSITE_SCHUR) { 662 jac->schur_user = jac->pmat[i]; 663 664 PetscCall(PetscObjectReference((PetscObject)jac->schur_user)); 665 } 666 } else { 667 const char *prefix; 668 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->pmat[i])); 669 PetscCall(MatGetOptionsPrefix(jac->pmat[i], &prefix)); 670 if (!prefix) { 671 PetscCall(KSPGetOptionsPrefix(ilink->ksp, &prefix)); 672 PetscCall(MatSetOptionsPrefix(jac->pmat[i], prefix)); 673 } 674 PetscCall(MatSetFromOptions(jac->pmat[i])); 675 PetscCall(MatViewFromOptions(jac->pmat[i], NULL, "-mat_view")); 676 } 677 /* create work vectors for each split */ 678 PetscCall(MatCreateVecs(jac->pmat[i], &jac->x[i], &jac->y[i])); 679 ilink->x = jac->x[i]; 680 ilink->y = jac->y[i]; 681 ilink->z = NULL; 682 /* compute scatter contexts needed by multiplicative versions and non-default splits */ 683 PetscCall(VecScatterCreate(xtmp, ilink->is, jac->x[i], NULL, &ilink->sctx)); 684 PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nearnullspace", (PetscObject *)&sp)); 685 if (sp) PetscCall(MatSetNearNullSpace(jac->pmat[i], sp)); 686 ilink = ilink->next; 687 } 688 PetscCall(VecDestroy(&xtmp)); 689 } else { 690 MatReuse scall; 691 MatNullSpace *nullsp = NULL; 692 693 if (pc->flag == DIFFERENT_NONZERO_PATTERN) { 694 PetscCall(MatGetNullSpaces(nsplit, jac->pmat, &nullsp)); 695 for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->pmat[i])); 696 scall = MAT_INITIAL_MATRIX; 697 } else scall = MAT_REUSE_MATRIX; 698 699 for (i = 0; i < nsplit; i++) { 700 Mat pmat; 701 702 /* Check for preconditioning matrix attached to IS */ 703 PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&pmat)); 704 if (!pmat) PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, scall, &jac->pmat[i])); 705 ilink = ilink->next; 706 } 707 if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->pmat, &nullsp)); 708 } 709 if (jac->diag_use_amat) { 710 ilink = jac->head; 711 if (!jac->mat) { 712 PetscCall(PetscMalloc1(nsplit, &jac->mat)); 713 for (i = 0; i < nsplit; i++) { 714 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->mat[i])); 715 ilink = ilink->next; 716 } 717 } else { 718 MatReuse scall; 719 MatNullSpace *nullsp = NULL; 720 721 if (pc->flag == DIFFERENT_NONZERO_PATTERN) { 722 PetscCall(MatGetNullSpaces(nsplit, jac->mat, &nullsp)); 723 for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->mat[i])); 724 scall = MAT_INITIAL_MATRIX; 725 } else scall = MAT_REUSE_MATRIX; 726 727 for (i = 0; i < nsplit; i++) { 728 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, scall, &jac->mat[i])); 729 ilink = ilink->next; 730 } 731 if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->mat, &nullsp)); 732 } 733 } else { 734 jac->mat = jac->pmat; 735 } 736 737 /* Check for null space attached to IS */ 738 ilink = jac->head; 739 for (i = 0; i < nsplit; i++) { 740 MatNullSpace sp; 741 742 PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nullspace", (PetscObject *)&sp)); 743 if (sp) PetscCall(MatSetNullSpace(jac->mat[i], sp)); 744 ilink = ilink->next; 745 } 746 747 if (jac->type != PC_COMPOSITE_ADDITIVE && jac->type != PC_COMPOSITE_SCHUR && jac->type != PC_COMPOSITE_GKB) { 748 /* extract the rows of the matrix associated with each field: used for efficient computation of residual inside algorithm */ 749 /* FIXME: Can/should we reuse jac->mat whenever (jac->diag_use_amat) is true? */ 750 ilink = jac->head; 751 if (nsplit == 2 && jac->type == PC_COMPOSITE_MULTIPLICATIVE) { 752 /* special case need where Afield[0] is not needed and only certain columns of Afield[1] are needed since update is only on those rows of the solution */ 753 if (!jac->Afield) { 754 PetscCall(PetscCalloc1(nsplit, &jac->Afield)); 755 if (jac->offdiag_use_amat) { 756 PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1])); 757 } else { 758 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1])); 759 } 760 } else { 761 MatReuse scall; 762 763 if (pc->flag == DIFFERENT_NONZERO_PATTERN) { 764 PetscCall(MatDestroy(&jac->Afield[1])); 765 scall = MAT_INITIAL_MATRIX; 766 } else scall = MAT_REUSE_MATRIX; 767 768 if (jac->offdiag_use_amat) { 769 PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, scall, &jac->Afield[1])); 770 } else { 771 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, scall, &jac->Afield[1])); 772 } 773 } 774 } else { 775 if (!jac->Afield) { 776 PetscCall(PetscMalloc1(nsplit, &jac->Afield)); 777 for (i = 0; i < nsplit; i++) { 778 if (jac->offdiag_use_amat) { 779 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i])); 780 } else { 781 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i])); 782 } 783 ilink = ilink->next; 784 } 785 } else { 786 MatReuse scall; 787 if (pc->flag == DIFFERENT_NONZERO_PATTERN) { 788 for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->Afield[i])); 789 scall = MAT_INITIAL_MATRIX; 790 } else scall = MAT_REUSE_MATRIX; 791 792 for (i = 0; i < nsplit; i++) { 793 if (jac->offdiag_use_amat) { 794 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, scall, &jac->Afield[i])); 795 } else { 796 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, scall, &jac->Afield[i])); 797 } 798 ilink = ilink->next; 799 } 800 } 801 } 802 } 803 804 if (jac->type == PC_COMPOSITE_SCHUR) { 805 IS ccis; 806 PetscBool isset, isspd; 807 PetscInt rstart, rend; 808 char lscname[256]; 809 PetscObject LSC_L; 810 PetscBool set, flg; 811 812 PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use Schur complement preconditioner you must have exactly 2 fields"); 813 814 /* If pc->mat is SPD, don't scale by -1 the Schur complement */ 815 if (jac->schurscale == (PetscScalar)-1.0) { 816 PetscCall(MatIsSPDKnown(pc->pmat, &isset, &isspd)); 817 jac->schurscale = (isset && isspd) ? 1.0 : -1.0; 818 } 819 820 /* When extracting off-diagonal submatrices, we take complements from this range */ 821 PetscCall(MatGetOwnershipRangeColumn(pc->mat, &rstart, &rend)); 822 PetscCall(PetscObjectTypeCompareAny(jac->offdiag_use_amat ? (PetscObject)pc->mat : (PetscObject)pc->pmat, &flg, MATSEQSBAIJ, MATMPISBAIJ, "")); 823 824 if (jac->schur) { 825 KSP kspA = jac->head->ksp, kspInner = NULL, kspUpper = jac->kspupper; 826 MatReuse scall; 827 828 if (pc->flag == DIFFERENT_NONZERO_PATTERN) { 829 scall = MAT_INITIAL_MATRIX; 830 PetscCall(MatDestroy(&jac->B)); 831 PetscCall(MatDestroy(&jac->C)); 832 } else scall = MAT_REUSE_MATRIX; 833 834 PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner)); 835 ilink = jac->head; 836 PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis)); 837 if (jac->offdiag_use_amat) { 838 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, scall, &jac->B)); 839 } else { 840 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, scall, &jac->B)); 841 } 842 PetscCall(ISDestroy(&ccis)); 843 if (!flg) { 844 ilink = ilink->next; 845 PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis)); 846 if (jac->offdiag_use_amat) { 847 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, scall, &jac->C)); 848 } else { 849 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, scall, &jac->C)); 850 } 851 PetscCall(ISDestroy(&ccis)); 852 } else { 853 PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &set, &flg)); 854 if (set && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C)); 855 else PetscCall(MatCreateTranspose(jac->B, &jac->C)); 856 } 857 PetscCall(MatSchurComplementUpdateSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1])); 858 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) { 859 PetscCall(MatDestroy(&jac->schurp)); 860 PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp)); 861 } 862 if (kspA != kspInner) PetscCall(KSPSetOperators(kspA, jac->mat[0], jac->pmat[0])); 863 if (kspUpper != kspA) PetscCall(KSPSetOperators(kspUpper, jac->mat[0], jac->pmat[0])); 864 PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac))); 865 } else { 866 const char *Dprefix; 867 char schurprefix[256], schurmatprefix[256]; 868 char schurtestoption[256]; 869 MatNullSpace sp; 870 KSP kspt; 871 872 /* extract the A01 and A10 matrices */ 873 ilink = jac->head; 874 PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis)); 875 if (jac->offdiag_use_amat) { 876 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B)); 877 } else { 878 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B)); 879 } 880 PetscCall(ISDestroy(&ccis)); 881 ilink = ilink->next; 882 if (!flg) { 883 PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis)); 884 if (jac->offdiag_use_amat) { 885 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C)); 886 } else { 887 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C)); 888 } 889 PetscCall(ISDestroy(&ccis)); 890 } else { 891 PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &set, &flg)); 892 if (set && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C)); 893 else PetscCall(MatCreateTranspose(jac->B, &jac->C)); 894 } 895 /* Use mat[0] (diagonal block of Amat) preconditioned by pmat[0] to define Schur complement */ 896 PetscCall(MatCreate(((PetscObject)jac->mat[0])->comm, &jac->schur)); 897 PetscCall(MatSetType(jac->schur, MATSCHURCOMPLEMENT)); 898 PetscCall(MatSchurComplementSetSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1])); 899 PetscCall(PetscSNPrintf(schurmatprefix, sizeof(schurmatprefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname)); 900 PetscCall(MatSetOptionsPrefix(jac->schur, schurmatprefix)); 901 PetscCall(MatSchurComplementGetKSP(jac->schur, &kspt)); 902 PetscCall(KSPSetOptionsPrefix(kspt, schurmatprefix)); 903 904 /* Note: this is not true in general */ 905 PetscCall(MatGetNullSpace(jac->mat[1], &sp)); 906 if (sp) PetscCall(MatSetNullSpace(jac->schur, sp)); 907 908 PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_inner_", ilink->splitname)); 909 PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg)); 910 if (flg) { 911 DM dmInner; 912 KSP kspInner; 913 PC pcInner; 914 915 PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner)); 916 PetscCall(KSPReset(kspInner)); 917 PetscCall(KSPSetOperators(kspInner, jac->mat[0], jac->pmat[0])); 918 PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_inner_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname)); 919 /* Indent this deeper to emphasize the "inner" nature of this solver. */ 920 PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner, (PetscObject)pc, 2)); 921 PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner->pc, (PetscObject)pc, 2)); 922 PetscCall(KSPSetOptionsPrefix(kspInner, schurprefix)); 923 924 /* Set DM for new solver */ 925 PetscCall(KSPGetDM(jac->head->ksp, &dmInner)); 926 PetscCall(KSPSetDM(kspInner, dmInner)); 927 PetscCall(KSPSetDMActive(kspInner, PETSC_FALSE)); 928 929 /* Defaults to PCKSP as preconditioner */ 930 PetscCall(KSPGetPC(kspInner, &pcInner)); 931 PetscCall(PCSetType(pcInner, PCKSP)); 932 PetscCall(PCKSPSetKSP(pcInner, jac->head->ksp)); 933 } else { 934 /* Use the outer solver for the inner solve, but revert the KSPPREONLY from PCFieldSplitSetFields_FieldSplit or 935 * PCFieldSplitSetIS_FieldSplit. We don't want KSPPREONLY because it makes the Schur complement inexact, 936 * preventing Schur complement reduction to be an accurate solve. Usually when an iterative solver is used for 937 * S = D - C A_inner^{-1} B, we expect S to be defined using an accurate definition of A_inner^{-1}, so we make 938 * GMRES the default. Note that it is also common to use PREONLY for S, in which case S may not be used 939 * directly, and the user is responsible for setting an inexact method for fieldsplit's A^{-1}. */ 940 PetscCall(KSPSetType(jac->head->ksp, KSPGMRES)); 941 PetscCall(MatSchurComplementSetKSP(jac->schur, jac->head->ksp)); 942 } 943 PetscCall(KSPSetOperators(jac->head->ksp, jac->mat[0], jac->pmat[0])); 944 PetscCall(KSPSetFromOptions(jac->head->ksp)); 945 PetscCall(MatSetFromOptions(jac->schur)); 946 947 PetscCall(PetscObjectTypeCompare((PetscObject)jac->schur, MATSCHURCOMPLEMENT, &flg)); 948 if (flg) { /* Need to do this otherwise PCSetUp_KSP will overwrite the amat of jac->head->ksp */ 949 KSP kspInner; 950 PC pcInner; 951 952 PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner)); 953 PetscCall(KSPGetPC(kspInner, &pcInner)); 954 PetscCall(PetscObjectTypeCompare((PetscObject)pcInner, PCKSP, &flg)); 955 if (flg) { 956 KSP ksp; 957 958 PetscCall(PCKSPGetKSP(pcInner, &ksp)); 959 if (ksp == jac->head->ksp) PetscCall(PCSetUseAmat(pcInner, PETSC_TRUE)); 960 } 961 } 962 PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_upper_", ilink->splitname)); 963 PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg)); 964 if (flg) { 965 DM dmInner; 966 967 PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_upper_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname)); 968 PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspupper)); 969 PetscCall(KSPSetNestLevel(jac->kspupper, pc->kspnestlevel)); 970 PetscCall(KSPSetErrorIfNotConverged(jac->kspupper, pc->erroriffailure)); 971 PetscCall(KSPSetOptionsPrefix(jac->kspupper, schurprefix)); 972 PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper, (PetscObject)pc, 1)); 973 PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper->pc, (PetscObject)pc, 1)); 974 PetscCall(KSPGetDM(jac->head->ksp, &dmInner)); 975 PetscCall(KSPSetDM(jac->kspupper, dmInner)); 976 PetscCall(KSPSetDMActive(jac->kspupper, PETSC_FALSE)); 977 PetscCall(KSPSetFromOptions(jac->kspupper)); 978 PetscCall(KSPSetOperators(jac->kspupper, jac->mat[0], jac->pmat[0])); 979 PetscCall(VecDuplicate(jac->head->x, &jac->head->z)); 980 } else { 981 jac->kspupper = jac->head->ksp; 982 PetscCall(PetscObjectReference((PetscObject)jac->head->ksp)); 983 } 984 985 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp)); 986 PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspschur)); 987 PetscCall(KSPSetNestLevel(jac->kspschur, pc->kspnestlevel)); 988 PetscCall(KSPSetErrorIfNotConverged(jac->kspschur, pc->erroriffailure)); 989 PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspschur, (PetscObject)pc, 1)); 990 if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) { 991 PC pcschur; 992 PetscCall(KSPGetPC(jac->kspschur, &pcschur)); 993 PetscCall(PCSetType(pcschur, PCNONE)); 994 /* Note: This is bad if there exist preconditioners for MATSCHURCOMPLEMENT */ 995 } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL) { 996 PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user)); 997 } 998 PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac))); 999 PetscCall(KSPGetOptionsPrefix(jac->head->next->ksp, &Dprefix)); 1000 PetscCall(KSPSetOptionsPrefix(jac->kspschur, Dprefix)); 1001 /* propagate DM */ 1002 { 1003 DM sdm; 1004 PetscCall(KSPGetDM(jac->head->next->ksp, &sdm)); 1005 if (sdm) { 1006 PetscCall(KSPSetDM(jac->kspschur, sdm)); 1007 PetscCall(KSPSetDMActive(jac->kspschur, PETSC_FALSE)); 1008 } 1009 } 1010 /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */ 1011 /* need to call this every time, since the jac->kspschur is freshly created, otherwise its options never get set */ 1012 PetscCall(KSPSetFromOptions(jac->kspschur)); 1013 } 1014 PetscCall(MatAssemblyBegin(jac->schur, MAT_FINAL_ASSEMBLY)); 1015 PetscCall(MatAssemblyEnd(jac->schur, MAT_FINAL_ASSEMBLY)); 1016 1017 /* HACK: special support to forward L and Lp matrices that might be used by PCLSC */ 1018 PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_L", ilink->splitname)); 1019 PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, (PetscObject *)&LSC_L)); 1020 if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, (PetscObject *)&LSC_L)); 1021 if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_L", (PetscObject)LSC_L)); 1022 PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_Lp", ilink->splitname)); 1023 PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, (PetscObject *)&LSC_L)); 1024 if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, (PetscObject *)&LSC_L)); 1025 if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_Lp", (PetscObject)LSC_L)); 1026 } else if (jac->type == PC_COMPOSITE_GKB) { 1027 IS ccis; 1028 PetscInt rstart, rend; 1029 1030 PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use GKB preconditioner you must have exactly 2 fields"); 1031 1032 ilink = jac->head; 1033 1034 /* When extracting off-diagonal submatrices, we take complements from this range */ 1035 PetscCall(MatGetOwnershipRangeColumn(pc->mat, &rstart, &rend)); 1036 1037 PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis)); 1038 if (jac->offdiag_use_amat) { 1039 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B)); 1040 } else { 1041 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B)); 1042 } 1043 PetscCall(ISDestroy(&ccis)); 1044 /* Create work vectors for GKB algorithm */ 1045 PetscCall(VecDuplicate(ilink->x, &jac->u)); 1046 PetscCall(VecDuplicate(ilink->x, &jac->Hu)); 1047 PetscCall(VecDuplicate(ilink->x, &jac->w2)); 1048 ilink = ilink->next; 1049 PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis)); 1050 if (jac->offdiag_use_amat) { 1051 PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C)); 1052 } else { 1053 PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C)); 1054 } 1055 PetscCall(ISDestroy(&ccis)); 1056 /* Create work vectors for GKB algorithm */ 1057 PetscCall(VecDuplicate(ilink->x, &jac->v)); 1058 PetscCall(VecDuplicate(ilink->x, &jac->d)); 1059 PetscCall(VecDuplicate(ilink->x, &jac->w1)); 1060 PetscCall(MatGolubKahanComputeExplicitOperator(jac->mat[0], jac->B, jac->C, &jac->H, jac->gkbnu)); 1061 PetscCall(PetscCalloc1(jac->gkbdelay, &jac->vecz)); 1062 1063 ilink = jac->head; 1064 PetscCall(KSPSetOperators(ilink->ksp, jac->H, jac->H)); 1065 if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp)); 1066 /* Create gkb_monitor context */ 1067 if (jac->gkbmonitor) { 1068 PetscInt tablevel; 1069 PetscCall(PetscViewerCreate(PETSC_COMM_WORLD, &jac->gkbviewer)); 1070 PetscCall(PetscViewerSetType(jac->gkbviewer, PETSCVIEWERASCII)); 1071 PetscCall(PetscObjectGetTabLevel((PetscObject)ilink->ksp, &tablevel)); 1072 PetscCall(PetscViewerASCIISetTab(jac->gkbviewer, tablevel)); 1073 PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)ilink->ksp, 1)); 1074 } 1075 } else { 1076 /* set up the individual splits' PCs */ 1077 i = 0; 1078 ilink = jac->head; 1079 while (ilink) { 1080 PetscCall(KSPSetOperators(ilink->ksp, jac->mat[i], jac->pmat[i])); 1081 /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */ 1082 if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp)); 1083 i++; 1084 ilink = ilink->next; 1085 } 1086 } 1087 1088 /* Set coordinates to the sub PC objects whenever these are set */ 1089 if (jac->coordinates_set) { 1090 PC pc_coords; 1091 if (jac->type == PC_COMPOSITE_SCHUR) { 1092 // Head is first block. 1093 PetscCall(KSPGetPC(jac->head->ksp, &pc_coords)); 1094 PetscCall(PCSetCoordinates(pc_coords, jac->head->dim, jac->head->ndofs, jac->head->coords)); 1095 // Second one is Schur block, but its KSP object is in kspschur. 1096 PetscCall(KSPGetPC(jac->kspschur, &pc_coords)); 1097 PetscCall(PCSetCoordinates(pc_coords, jac->head->next->dim, jac->head->next->ndofs, jac->head->next->coords)); 1098 } else if (jac->type == PC_COMPOSITE_GKB) { 1099 PetscCall(PetscInfo(pc, "Warning: Setting coordinates does nothing for the GKB Fieldpslit preconditioner\n")); 1100 } else { 1101 ilink = jac->head; 1102 while (ilink) { 1103 PetscCall(KSPGetPC(ilink->ksp, &pc_coords)); 1104 PetscCall(PCSetCoordinates(pc_coords, ilink->dim, ilink->ndofs, ilink->coords)); 1105 ilink = ilink->next; 1106 } 1107 } 1108 } 1109 1110 jac->suboptionsset = PETSC_TRUE; 1111 PetscFunctionReturn(PETSC_SUCCESS); 1112 } 1113 1114 #define FieldSplitSplitSolveAdd(ilink, xx, yy) \ 1115 ((PetscErrorCode)(VecScatterBegin(ilink->sctx, xx, ilink->x, INSERT_VALUES, SCATTER_FORWARD) || VecScatterEnd(ilink->sctx, xx, ilink->x, INSERT_VALUES, SCATTER_FORWARD) || PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL) || \ 1116 KSPSolve(ilink->ksp, ilink->x, ilink->y) || KSPCheckSolve(ilink->ksp, pc, ilink->y) || PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL) || VecScatterBegin(ilink->sctx, ilink->y, yy, ADD_VALUES, SCATTER_REVERSE) || \ 1117 VecScatterEnd(ilink->sctx, ilink->y, yy, ADD_VALUES, SCATTER_REVERSE))) 1118 1119 static PetscErrorCode PCApply_FieldSplit_Schur(PC pc, Vec x, Vec y) 1120 { 1121 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1122 PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next; 1123 KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper; 1124 1125 PetscFunctionBegin; 1126 switch (jac->schurfactorization) { 1127 case PC_FIELDSPLIT_SCHUR_FACT_DIAG: 1128 /* [A00 0; 0 -S], positive definite, suitable for MINRES */ 1129 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1130 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1131 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1132 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1133 PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y)); 1134 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1135 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1136 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1137 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1138 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1139 PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y)); 1140 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1141 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1142 PetscCall(VecScale(ilinkD->y, jac->schurscale)); 1143 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1144 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1145 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1146 break; 1147 case PC_FIELDSPLIT_SCHUR_FACT_LOWER: 1148 /* [A00 0; A10 S], suitable for left preconditioning */ 1149 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1150 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1151 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1152 PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y)); 1153 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1154 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1155 PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x)); 1156 PetscCall(VecScale(ilinkD->x, -1.)); 1157 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1158 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1159 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1160 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1161 PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y)); 1162 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1163 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1164 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1165 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1166 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1167 break; 1168 case PC_FIELDSPLIT_SCHUR_FACT_UPPER: 1169 /* [A00 A01; 0 S], suitable for right preconditioning */ 1170 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1171 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1172 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1173 PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y)); 1174 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1175 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1176 PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->x)); 1177 PetscCall(VecScale(ilinkA->x, -1.)); 1178 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD)); 1179 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1180 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD)); 1181 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1182 PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y)); 1183 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1184 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1185 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1186 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1187 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1188 break; 1189 case PC_FIELDSPLIT_SCHUR_FACT_FULL: 1190 /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1] */ 1191 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1192 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1193 PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL)); 1194 PetscCall(KSPSolve(kspLower, ilinkA->x, ilinkA->y)); 1195 PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->y)); 1196 PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL)); 1197 PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x)); 1198 PetscCall(VecScale(ilinkD->x, -1.0)); 1199 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1200 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1201 1202 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1203 PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y)); 1204 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1205 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1206 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1207 1208 if (kspUpper == kspA) { 1209 PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->y)); 1210 PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y)); 1211 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1212 PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y)); 1213 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1214 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1215 } else { 1216 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1217 PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y)); 1218 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1219 PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->x)); 1220 PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL)); 1221 PetscCall(KSPSolve(kspUpper, ilinkA->x, ilinkA->z)); 1222 PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->z)); 1223 PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL)); 1224 PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z)); 1225 } 1226 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1227 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1228 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1229 } 1230 PetscFunctionReturn(PETSC_SUCCESS); 1231 } 1232 1233 static PetscErrorCode PCApplyTranspose_FieldSplit_Schur(PC pc, Vec x, Vec y) 1234 { 1235 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1236 PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next; 1237 KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper; 1238 1239 PetscFunctionBegin; 1240 switch (jac->schurfactorization) { 1241 case PC_FIELDSPLIT_SCHUR_FACT_DIAG: 1242 /* [A00 0; 0 -S], positive definite, suitable for MINRES */ 1243 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1244 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1245 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1246 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1247 PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y)); 1248 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1249 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1250 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1251 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1252 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1253 PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y)); 1254 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1255 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1256 PetscCall(VecScale(ilinkD->y, jac->schurscale)); 1257 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1258 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1259 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1260 break; 1261 case PC_FIELDSPLIT_SCHUR_FACT_UPPER: 1262 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1263 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1264 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1265 PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y)); 1266 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1267 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1268 PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x)); 1269 PetscCall(VecScale(ilinkD->x, -1.)); 1270 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1271 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1272 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1273 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1274 PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y)); 1275 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1276 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1277 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1278 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1279 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1280 break; 1281 case PC_FIELDSPLIT_SCHUR_FACT_LOWER: 1282 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1283 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1284 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1285 PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y)); 1286 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1287 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1288 PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x)); 1289 PetscCall(VecScale(ilinkA->x, -1.)); 1290 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD)); 1291 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1292 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD)); 1293 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1294 PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y)); 1295 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1296 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1297 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1298 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1299 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1300 break; 1301 case PC_FIELDSPLIT_SCHUR_FACT_FULL: 1302 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1303 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1304 PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL)); 1305 PetscCall(KSPSolveTranspose(kspUpper, ilinkA->x, ilinkA->y)); 1306 PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->y)); 1307 PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL)); 1308 PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x)); 1309 PetscCall(VecScale(ilinkD->x, -1.0)); 1310 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1311 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD)); 1312 1313 PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1314 PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y)); 1315 PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y)); 1316 PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL)); 1317 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1318 1319 if (kspLower == kspA) { 1320 PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->y)); 1321 PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y)); 1322 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1323 PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y)); 1324 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1325 PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1326 } else { 1327 PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL)); 1328 PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y)); 1329 PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y)); 1330 PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x)); 1331 PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL)); 1332 PetscCall(KSPSolveTranspose(kspLower, ilinkA->x, ilinkA->z)); 1333 PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->z)); 1334 PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL)); 1335 PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z)); 1336 } 1337 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1338 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1339 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1340 } 1341 PetscFunctionReturn(PETSC_SUCCESS); 1342 } 1343 1344 static PetscErrorCode PCApply_FieldSplit(PC pc, Vec x, Vec y) 1345 { 1346 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1347 PC_FieldSplitLink ilink = jac->head; 1348 PetscInt cnt, bs; 1349 1350 PetscFunctionBegin; 1351 if (jac->type == PC_COMPOSITE_ADDITIVE) { 1352 if (jac->defaultsplit) { 1353 PetscCall(VecGetBlockSize(x, &bs)); 1354 PetscCheck(jac->bs <= 0 || bs == jac->bs, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Blocksize of x vector %" PetscInt_FMT " does not match fieldsplit blocksize %" PetscInt_FMT, bs, jac->bs); 1355 PetscCall(VecGetBlockSize(y, &bs)); 1356 PetscCheck(jac->bs <= 0 || bs == jac->bs, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Blocksize of y vector %" PetscInt_FMT " does not match fieldsplit blocksize %" PetscInt_FMT, bs, jac->bs); 1357 PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES)); 1358 while (ilink) { 1359 PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1360 PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y)); 1361 PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y)); 1362 PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1363 ilink = ilink->next; 1364 } 1365 PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES)); 1366 } else { 1367 PetscCall(VecSet(y, 0.0)); 1368 while (ilink) { 1369 PetscCall(FieldSplitSplitSolveAdd(ilink, x, y)); 1370 ilink = ilink->next; 1371 } 1372 } 1373 } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) { 1374 PetscCall(VecSet(y, 0.0)); 1375 /* solve on first block for first block variables */ 1376 PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD)); 1377 PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD)); 1378 PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1379 PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y)); 1380 PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y)); 1381 PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1382 PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1383 PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1384 1385 /* compute the residual only onto second block variables using first block variables */ 1386 PetscCall(MatMult(jac->Afield[1], ilink->y, ilink->next->x)); 1387 ilink = ilink->next; 1388 PetscCall(VecScale(ilink->x, -1.0)); 1389 PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD)); 1390 PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD)); 1391 1392 /* solve on second block variables */ 1393 PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1394 PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y)); 1395 PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y)); 1396 PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1397 PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1398 PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1399 } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 1400 if (!jac->w1) { 1401 PetscCall(VecDuplicate(x, &jac->w1)); 1402 PetscCall(VecDuplicate(x, &jac->w2)); 1403 } 1404 PetscCall(VecSet(y, 0.0)); 1405 PetscCall(FieldSplitSplitSolveAdd(ilink, x, y)); 1406 cnt = 1; 1407 while (ilink->next) { 1408 ilink = ilink->next; 1409 /* compute the residual only over the part of the vector needed */ 1410 PetscCall(MatMult(jac->Afield[cnt++], y, ilink->x)); 1411 PetscCall(VecScale(ilink->x, -1.0)); 1412 PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD)); 1413 PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD)); 1414 PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1415 PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y)); 1416 PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y)); 1417 PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1418 PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1419 PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1420 } 1421 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 1422 cnt -= 2; 1423 while (ilink->previous) { 1424 ilink = ilink->previous; 1425 /* compute the residual only over the part of the vector needed */ 1426 PetscCall(MatMult(jac->Afield[cnt--], y, ilink->x)); 1427 PetscCall(VecScale(ilink->x, -1.0)); 1428 PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD)); 1429 PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD)); 1430 PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1431 PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y)); 1432 PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y)); 1433 PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1434 PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1435 PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE)); 1436 } 1437 } 1438 } else SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Unsupported or unknown composition %d", (int)jac->type); 1439 PetscFunctionReturn(PETSC_SUCCESS); 1440 } 1441 1442 static PetscErrorCode PCApply_FieldSplit_GKB(PC pc, Vec x, Vec y) 1443 { 1444 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1445 PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next; 1446 KSP ksp = ilinkA->ksp; 1447 Vec u, v, Hu, d, work1, work2; 1448 PetscScalar alpha, z, nrmz2, *vecz; 1449 PetscReal lowbnd, nu, beta; 1450 PetscInt j, iterGKB; 1451 1452 PetscFunctionBegin; 1453 PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1454 PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1455 PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD)); 1456 PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD)); 1457 1458 u = jac->u; 1459 v = jac->v; 1460 Hu = jac->Hu; 1461 d = jac->d; 1462 work1 = jac->w1; 1463 work2 = jac->w2; 1464 vecz = jac->vecz; 1465 1466 /* Change RHS to comply with matrix regularization H = A + nu*B*B' */ 1467 /* Add q = q + nu*B*b */ 1468 if (jac->gkbnu) { 1469 nu = jac->gkbnu; 1470 PetscCall(VecScale(ilinkD->x, jac->gkbnu)); 1471 PetscCall(MatMultAdd(jac->B, ilinkD->x, ilinkA->x, ilinkA->x)); /* q = q + nu*B*b */ 1472 } else { 1473 /* Situation when no augmented Lagrangian is used. Then we set inner */ 1474 /* matrix N = I in [Ar13], and thus nu = 1. */ 1475 nu = 1; 1476 } 1477 1478 /* Transform rhs from [q,tilde{b}] to [0,b] */ 1479 PetscCall(PetscLogEventBegin(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL)); 1480 PetscCall(KSPSolve(ksp, ilinkA->x, ilinkA->y)); 1481 PetscCall(KSPCheckSolve(ksp, pc, ilinkA->y)); 1482 PetscCall(PetscLogEventEnd(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL)); 1483 PetscCall(MatMultHermitianTranspose(jac->B, ilinkA->y, work1)); 1484 PetscCall(VecAXPBY(work1, 1.0 / nu, -1.0, ilinkD->x)); /* c = b - B'*x */ 1485 1486 /* First step of algorithm */ 1487 PetscCall(VecNorm(work1, NORM_2, &beta)); /* beta = sqrt(nu*c'*c)*/ 1488 KSPCheckDot(ksp, beta); 1489 beta = PetscSqrtReal(nu) * beta; 1490 PetscCall(VecAXPBY(v, nu / beta, 0.0, work1)); /* v = nu/beta *c */ 1491 PetscCall(MatMult(jac->B, v, work2)); /* u = H^{-1}*B*v */ 1492 PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL)); 1493 PetscCall(KSPSolve(ksp, work2, u)); 1494 PetscCall(KSPCheckSolve(ksp, pc, u)); 1495 PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL)); 1496 PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */ 1497 PetscCall(VecDot(Hu, u, &alpha)); 1498 KSPCheckDot(ksp, alpha); 1499 PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite"); 1500 alpha = PetscSqrtReal(PetscAbsScalar(alpha)); 1501 PetscCall(VecScale(u, 1.0 / alpha)); 1502 PetscCall(VecAXPBY(d, 1.0 / alpha, 0.0, v)); /* v = nu/beta *c */ 1503 1504 z = beta / alpha; 1505 vecz[1] = z; 1506 1507 /* Computation of first iterate x(1) and p(1) */ 1508 PetscCall(VecAXPY(ilinkA->y, z, u)); 1509 PetscCall(VecCopy(d, ilinkD->y)); 1510 PetscCall(VecScale(ilinkD->y, -z)); 1511 1512 iterGKB = 1; 1513 lowbnd = 2 * jac->gkbtol; 1514 if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd)); 1515 1516 while (iterGKB < jac->gkbmaxit && lowbnd > jac->gkbtol) { 1517 iterGKB += 1; 1518 PetscCall(MatMultHermitianTranspose(jac->B, u, work1)); /* v <- nu*(B'*u-alpha/nu*v) */ 1519 PetscCall(VecAXPBY(v, nu, -alpha, work1)); 1520 PetscCall(VecNorm(v, NORM_2, &beta)); /* beta = sqrt(nu)*v'*v */ 1521 beta = beta / PetscSqrtReal(nu); 1522 PetscCall(VecScale(v, 1.0 / beta)); 1523 PetscCall(MatMult(jac->B, v, work2)); /* u <- H^{-1}*(B*v-beta*H*u) */ 1524 PetscCall(MatMult(jac->H, u, Hu)); 1525 PetscCall(VecAXPY(work2, -beta, Hu)); 1526 PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL)); 1527 PetscCall(KSPSolve(ksp, work2, u)); 1528 PetscCall(KSPCheckSolve(ksp, pc, u)); 1529 PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL)); 1530 PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */ 1531 PetscCall(VecDot(Hu, u, &alpha)); 1532 KSPCheckDot(ksp, alpha); 1533 PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite"); 1534 alpha = PetscSqrtReal(PetscAbsScalar(alpha)); 1535 PetscCall(VecScale(u, 1.0 / alpha)); 1536 1537 z = -beta / alpha * z; /* z <- beta/alpha*z */ 1538 vecz[0] = z; 1539 1540 /* Computation of new iterate x(i+1) and p(i+1) */ 1541 PetscCall(VecAXPBY(d, 1.0 / alpha, -beta / alpha, v)); /* d = (v-beta*d)/alpha */ 1542 PetscCall(VecAXPY(ilinkA->y, z, u)); /* r = r + z*u */ 1543 PetscCall(VecAXPY(ilinkD->y, -z, d)); /* p = p - z*d */ 1544 PetscCall(MatMult(jac->H, ilinkA->y, Hu)); /* ||u||_H = u'*H*u */ 1545 PetscCall(VecDot(Hu, ilinkA->y, &nrmz2)); 1546 1547 /* Compute Lower Bound estimate */ 1548 if (iterGKB > jac->gkbdelay) { 1549 lowbnd = 0.0; 1550 for (j = 0; j < jac->gkbdelay; j++) lowbnd += PetscAbsScalar(vecz[j] * vecz[j]); 1551 lowbnd = PetscSqrtReal(lowbnd / PetscAbsScalar(nrmz2)); 1552 } 1553 1554 for (j = 0; j < jac->gkbdelay - 1; j++) vecz[jac->gkbdelay - j - 1] = vecz[jac->gkbdelay - j - 2]; 1555 if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd)); 1556 } 1557 1558 PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1559 PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1560 PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1561 PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE)); 1562 1563 PetscFunctionReturn(PETSC_SUCCESS); 1564 } 1565 1566 #define FieldSplitSplitSolveAddTranspose(ilink, xx, yy) \ 1567 ((PetscErrorCode)(VecScatterBegin(ilink->sctx, xx, ilink->y, INSERT_VALUES, SCATTER_FORWARD) || VecScatterEnd(ilink->sctx, xx, ilink->y, INSERT_VALUES, SCATTER_FORWARD) || PetscLogEventBegin(ilink->event, ilink->ksp, ilink->y, ilink->x, NULL) || \ 1568 KSPSolveTranspose(ilink->ksp, ilink->y, ilink->x) || KSPCheckSolve(ilink->ksp, pc, ilink->x) || PetscLogEventEnd(ilink->event, ilink->ksp, ilink->y, ilink->x, NULL) || VecScatterBegin(ilink->sctx, ilink->x, yy, ADD_VALUES, SCATTER_REVERSE) || \ 1569 VecScatterEnd(ilink->sctx, ilink->x, yy, ADD_VALUES, SCATTER_REVERSE))) 1570 1571 static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc, Vec x, Vec y) 1572 { 1573 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1574 PC_FieldSplitLink ilink = jac->head; 1575 PetscInt bs; 1576 1577 PetscFunctionBegin; 1578 if (jac->type == PC_COMPOSITE_ADDITIVE) { 1579 if (jac->defaultsplit) { 1580 PetscCall(VecGetBlockSize(x, &bs)); 1581 PetscCheck(jac->bs <= 0 || bs == jac->bs, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Blocksize of x vector %" PetscInt_FMT " does not match fieldsplit blocksize %" PetscInt_FMT, bs, jac->bs); 1582 PetscCall(VecGetBlockSize(y, &bs)); 1583 PetscCheck(jac->bs <= 0 || bs == jac->bs, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Blocksize of y vector %" PetscInt_FMT " does not match fieldsplit blocksize %" PetscInt_FMT, bs, jac->bs); 1584 PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES)); 1585 while (ilink) { 1586 PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1587 PetscCall(KSPSolveTranspose(ilink->ksp, ilink->x, ilink->y)); 1588 PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y)); 1589 PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL)); 1590 ilink = ilink->next; 1591 } 1592 PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES)); 1593 } else { 1594 PetscCall(VecSet(y, 0.0)); 1595 while (ilink) { 1596 PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y)); 1597 ilink = ilink->next; 1598 } 1599 } 1600 } else { 1601 if (!jac->w1) { 1602 PetscCall(VecDuplicate(x, &jac->w1)); 1603 PetscCall(VecDuplicate(x, &jac->w2)); 1604 } 1605 PetscCall(VecSet(y, 0.0)); 1606 if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) { 1607 PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y)); 1608 while (ilink->next) { 1609 ilink = ilink->next; 1610 PetscCall(MatMultTranspose(pc->mat, y, jac->w1)); 1611 PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x)); 1612 PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y)); 1613 } 1614 while (ilink->previous) { 1615 ilink = ilink->previous; 1616 PetscCall(MatMultTranspose(pc->mat, y, jac->w1)); 1617 PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x)); 1618 PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y)); 1619 } 1620 } else { 1621 while (ilink->next) { /* get to last entry in linked list */ 1622 ilink = ilink->next; 1623 } 1624 PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y)); 1625 while (ilink->previous) { 1626 ilink = ilink->previous; 1627 PetscCall(MatMultTranspose(pc->mat, y, jac->w1)); 1628 PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x)); 1629 PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y)); 1630 } 1631 } 1632 } 1633 PetscFunctionReturn(PETSC_SUCCESS); 1634 } 1635 1636 static PetscErrorCode PCReset_FieldSplit(PC pc) 1637 { 1638 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1639 PC_FieldSplitLink ilink = jac->head, next; 1640 1641 PetscFunctionBegin; 1642 while (ilink) { 1643 PetscCall(KSPDestroy(&ilink->ksp)); 1644 PetscCall(VecDestroy(&ilink->x)); 1645 PetscCall(VecDestroy(&ilink->y)); 1646 PetscCall(VecDestroy(&ilink->z)); 1647 PetscCall(VecScatterDestroy(&ilink->sctx)); 1648 PetscCall(ISDestroy(&ilink->is)); 1649 PetscCall(ISDestroy(&ilink->is_col)); 1650 PetscCall(PetscFree(ilink->splitname)); 1651 PetscCall(PetscFree(ilink->fields)); 1652 PetscCall(PetscFree(ilink->fields_col)); 1653 next = ilink->next; 1654 PetscCall(PetscFree(ilink)); 1655 ilink = next; 1656 } 1657 jac->head = NULL; 1658 PetscCall(PetscFree2(jac->x, jac->y)); 1659 if (jac->mat && jac->mat != jac->pmat) { 1660 PetscCall(MatDestroyMatrices(jac->nsplits, &jac->mat)); 1661 } else if (jac->mat) { 1662 jac->mat = NULL; 1663 } 1664 if (jac->pmat) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->pmat)); 1665 if (jac->Afield) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->Afield)); 1666 jac->nsplits = 0; 1667 PetscCall(VecDestroy(&jac->w1)); 1668 PetscCall(VecDestroy(&jac->w2)); 1669 PetscCall(MatDestroy(&jac->schur)); 1670 PetscCall(MatDestroy(&jac->schurp)); 1671 PetscCall(MatDestroy(&jac->schur_user)); 1672 PetscCall(KSPDestroy(&jac->kspschur)); 1673 PetscCall(KSPDestroy(&jac->kspupper)); 1674 PetscCall(MatDestroy(&jac->B)); 1675 PetscCall(MatDestroy(&jac->C)); 1676 PetscCall(MatDestroy(&jac->H)); 1677 PetscCall(VecDestroy(&jac->u)); 1678 PetscCall(VecDestroy(&jac->v)); 1679 PetscCall(VecDestroy(&jac->Hu)); 1680 PetscCall(VecDestroy(&jac->d)); 1681 PetscCall(PetscFree(jac->vecz)); 1682 PetscCall(PetscViewerDestroy(&jac->gkbviewer)); 1683 jac->isrestrict = PETSC_FALSE; 1684 PetscFunctionReturn(PETSC_SUCCESS); 1685 } 1686 1687 static PetscErrorCode PCDestroy_FieldSplit(PC pc) 1688 { 1689 PetscFunctionBegin; 1690 PetscCall(PCReset_FieldSplit(pc)); 1691 PetscCall(PetscFree(pc->data)); 1692 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", NULL)); 1693 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", NULL)); 1694 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", NULL)); 1695 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", NULL)); 1696 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", NULL)); 1697 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", NULL)); 1698 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", NULL)); 1699 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL)); 1700 1701 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL)); 1702 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL)); 1703 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL)); 1704 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL)); 1705 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL)); 1706 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL)); 1707 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL)); 1708 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL)); 1709 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL)); 1710 PetscFunctionReturn(PETSC_SUCCESS); 1711 } 1712 1713 static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc, PetscOptionItems *PetscOptionsObject) 1714 { 1715 PetscInt bs; 1716 PetscBool flg; 1717 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1718 PCCompositeType ctype; 1719 1720 PetscFunctionBegin; 1721 PetscOptionsHeadBegin(PetscOptionsObject, "FieldSplit options"); 1722 PetscCall(PetscOptionsBool("-pc_fieldsplit_dm_splits", "Whether to use DMCreateFieldDecomposition() for splits", "PCFieldSplitSetDMSplits", jac->dm_splits, &jac->dm_splits, NULL)); 1723 PetscCall(PetscOptionsInt("-pc_fieldsplit_block_size", "Blocksize that defines number of fields", "PCFieldSplitSetBlockSize", jac->bs, &bs, &flg)); 1724 if (flg) PetscCall(PCFieldSplitSetBlockSize(pc, bs)); 1725 jac->diag_use_amat = pc->useAmat; 1726 PetscCall(PetscOptionsBool("-pc_fieldsplit_diag_use_amat", "Use Amat (not Pmat) to extract diagonal fieldsplit blocks", "PCFieldSplitSetDiagUseAmat", jac->diag_use_amat, &jac->diag_use_amat, NULL)); 1727 jac->offdiag_use_amat = pc->useAmat; 1728 PetscCall(PetscOptionsBool("-pc_fieldsplit_off_diag_use_amat", "Use Amat (not Pmat) to extract off-diagonal fieldsplit blocks", "PCFieldSplitSetOffDiagUseAmat", jac->offdiag_use_amat, &jac->offdiag_use_amat, NULL)); 1729 PetscCall(PetscOptionsBool("-pc_fieldsplit_detect_saddle_point", "Form 2-way split by detecting zero diagonal entries", "PCFieldSplitSetDetectSaddlePoint", jac->detect, &jac->detect, NULL)); 1730 PetscCall(PCFieldSplitSetDetectSaddlePoint(pc, jac->detect)); /* Sets split type and Schur PC type */ 1731 PetscCall(PetscOptionsEnum("-pc_fieldsplit_type", "Type of composition", "PCFieldSplitSetType", PCCompositeTypes, (PetscEnum)jac->type, (PetscEnum *)&ctype, &flg)); 1732 if (flg) PetscCall(PCFieldSplitSetType(pc, ctype)); 1733 /* Only setup fields once */ 1734 if ((jac->bs > 0) && (jac->nsplits == 0)) { 1735 /* only allow user to set fields from command line if bs is already known. 1736 otherwise user can set them in PCFieldSplitSetDefaults() */ 1737 PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc)); 1738 if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n")); 1739 } 1740 if (jac->type == PC_COMPOSITE_SCHUR) { 1741 PetscCall(PetscOptionsGetEnum(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_schur_factorization_type", PCFieldSplitSchurFactTypes, (PetscEnum *)&jac->schurfactorization, &flg)); 1742 if (flg) PetscCall(PetscInfo(pc, "Deprecated use of -pc_fieldsplit_schur_factorization_type\n")); 1743 PetscCall(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)); 1744 PetscCall(PetscOptionsEnum("-pc_fieldsplit_schur_precondition", "How to build preconditioner for Schur complement", "PCFieldSplitSetSchurPre", PCFieldSplitSchurPreTypes, (PetscEnum)jac->schurpre, (PetscEnum *)&jac->schurpre, NULL)); 1745 PetscCall(PetscOptionsScalar("-pc_fieldsplit_schur_scale", "Scale Schur complement", "PCFieldSplitSetSchurScale", jac->schurscale, &jac->schurscale, NULL)); 1746 } else if (jac->type == PC_COMPOSITE_GKB) { 1747 PetscCall(PetscOptionsReal("-pc_fieldsplit_gkb_tol", "The tolerance for the lower bound stopping criterion", "PCFieldSplitGKBTol", jac->gkbtol, &jac->gkbtol, NULL)); 1748 PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_delay", "The delay value for lower bound criterion", "PCFieldSplitGKBDelay", jac->gkbdelay, &jac->gkbdelay, NULL)); 1749 PetscCall(PetscOptionsBoundedReal("-pc_fieldsplit_gkb_nu", "Parameter in augmented Lagrangian approach", "PCFieldSplitGKBNu", jac->gkbnu, &jac->gkbnu, NULL, 0.0)); 1750 PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_maxit", "Maximum allowed number of iterations", "PCFieldSplitGKBMaxit", jac->gkbmaxit, &jac->gkbmaxit, NULL)); 1751 PetscCall(PetscOptionsBool("-pc_fieldsplit_gkb_monitor", "Prints number of GKB iterations and error", "PCFieldSplitGKB", jac->gkbmonitor, &jac->gkbmonitor, NULL)); 1752 } 1753 /* 1754 In the initial call to this routine the sub-solver data structures do not exist so we cannot call KSPSetFromOptions() on them yet. 1755 But after the initial setup of ALL the layers of sub-solvers is completed we do want to call KSPSetFromOptions() on the sub-solvers every time it 1756 is called on the outer solver in case changes were made in the options database 1757 1758 But even after PCSetUp_FieldSplit() is called all the options inside the inner levels of sub-solvers may still not have been set thus we only call the KSPSetFromOptions() 1759 if we know that the entire stack of sub-solvers below this have been complete instantiated, we check this by seeing if any solver iterations are complete. 1760 Without this extra check test p2p1fetidp_olof_full and others fail with incorrect matrix types. 1761 1762 There could be a negative side effect of calling the KSPSetFromOptions() below. 1763 1764 If one captured the PetscObjectState of the options database one could skip these calls if the database has not changed from the previous call 1765 */ 1766 if (jac->issetup) { 1767 PC_FieldSplitLink ilink = jac->head; 1768 if (jac->type == PC_COMPOSITE_SCHUR) { 1769 if (jac->kspupper && jac->kspupper->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspupper)); 1770 if (jac->kspschur && jac->kspschur->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspschur)); 1771 } 1772 while (ilink) { 1773 if (ilink->ksp->totalits > 0) PetscCall(KSPSetFromOptions(ilink->ksp)); 1774 ilink = ilink->next; 1775 } 1776 } 1777 PetscOptionsHeadEnd(); 1778 PetscFunctionReturn(PETSC_SUCCESS); 1779 } 1780 1781 static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc, const char splitname[], PetscInt n, const PetscInt *fields, const PetscInt *fields_col) 1782 { 1783 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1784 PC_FieldSplitLink ilink, next = jac->head; 1785 char prefix[128]; 1786 PetscInt i; 1787 1788 PetscFunctionBegin; 1789 if (jac->splitdefined) { 1790 PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname)); 1791 PetscFunctionReturn(PETSC_SUCCESS); 1792 } 1793 for (i = 0; i < n; i++) { 1794 PetscCheck(fields[i] < jac->bs, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " requested but only %" PetscInt_FMT " exist", fields[i], jac->bs); 1795 PetscCheck(fields[i] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", fields[i]); 1796 } 1797 PetscCall(PetscNew(&ilink)); 1798 if (splitname) { 1799 PetscCall(PetscStrallocpy(splitname, &ilink->splitname)); 1800 } else { 1801 PetscCall(PetscMalloc1(3, &ilink->splitname)); 1802 PetscCall(PetscSNPrintf(ilink->splitname, 2, "%" PetscInt_FMT, jac->nsplits)); 1803 } 1804 ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + jac->nsplits : KSP_Solve_FS_0 + 4; /* Any split great than 4 gets logged in the 4th split */ 1805 PetscCall(PetscMalloc1(n, &ilink->fields)); 1806 PetscCall(PetscArraycpy(ilink->fields, fields, n)); 1807 PetscCall(PetscMalloc1(n, &ilink->fields_col)); 1808 PetscCall(PetscArraycpy(ilink->fields_col, fields_col, n)); 1809 1810 ilink->nfields = n; 1811 ilink->next = NULL; 1812 PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp)); 1813 PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel)); 1814 PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure)); 1815 PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1)); 1816 PetscCall(KSPSetType(ilink->ksp, KSPPREONLY)); 1817 1818 PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname)); 1819 PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix)); 1820 1821 if (!next) { 1822 jac->head = ilink; 1823 ilink->previous = NULL; 1824 } else { 1825 while (next->next) next = next->next; 1826 next->next = ilink; 1827 ilink->previous = next; 1828 } 1829 jac->nsplits++; 1830 PetscFunctionReturn(PETSC_SUCCESS); 1831 } 1832 1833 static PetscErrorCode PCFieldSplitSchurGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp) 1834 { 1835 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1836 1837 PetscFunctionBegin; 1838 *subksp = NULL; 1839 if (n) *n = 0; 1840 if (jac->type == PC_COMPOSITE_SCHUR) { 1841 PetscInt nn; 1842 1843 PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitSchurGetSubKSP()"); 1844 PetscCheck(jac->nsplits == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unexpected number of splits %" PetscInt_FMT " != 2", jac->nsplits); 1845 nn = jac->nsplits + (jac->kspupper != jac->head->ksp ? 1 : 0); 1846 PetscCall(PetscMalloc1(nn, subksp)); 1847 (*subksp)[0] = jac->head->ksp; 1848 (*subksp)[1] = jac->kspschur; 1849 if (jac->kspupper != jac->head->ksp) (*subksp)[2] = jac->kspupper; 1850 if (n) *n = nn; 1851 } 1852 PetscFunctionReturn(PETSC_SUCCESS); 1853 } 1854 1855 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc, PetscInt *n, KSP **subksp) 1856 { 1857 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1858 1859 PetscFunctionBegin; 1860 PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitGetSubKSP()"); 1861 PetscCall(PetscMalloc1(jac->nsplits, subksp)); 1862 PetscCall(MatSchurComplementGetKSP(jac->schur, *subksp)); 1863 1864 (*subksp)[1] = jac->kspschur; 1865 if (n) *n = jac->nsplits; 1866 PetscFunctionReturn(PETSC_SUCCESS); 1867 } 1868 1869 static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp) 1870 { 1871 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1872 PetscInt cnt = 0; 1873 PC_FieldSplitLink ilink = jac->head; 1874 1875 PetscFunctionBegin; 1876 PetscCall(PetscMalloc1(jac->nsplits, subksp)); 1877 while (ilink) { 1878 (*subksp)[cnt++] = ilink->ksp; 1879 ilink = ilink->next; 1880 } 1881 PetscCheck(cnt == jac->nsplits, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Corrupt PCFIELDSPLIT object: number of splits in linked list %" PetscInt_FMT " does not match number in object %" PetscInt_FMT, cnt, jac->nsplits); 1882 if (n) *n = jac->nsplits; 1883 PetscFunctionReturn(PETSC_SUCCESS); 1884 } 1885 1886 /*@C 1887 PCFieldSplitRestrictIS - Restricts the fieldsplit `IS`s to be within a given `IS`. 1888 1889 Input Parameters: 1890 + pc - the preconditioner context 1891 - isy - the index set that defines the indices to which the fieldsplit is to be restricted 1892 1893 Level: advanced 1894 1895 Developer Notes: 1896 It seems the resulting `IS`s will not cover the entire space, so 1897 how can they define a convergent preconditioner? Needs explaining. 1898 1899 .seealso: [](sec_block_matrices), `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()` 1900 @*/ 1901 PetscErrorCode PCFieldSplitRestrictIS(PC pc, IS isy) 1902 { 1903 PetscFunctionBegin; 1904 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1905 PetscValidHeaderSpecific(isy, IS_CLASSID, 2); 1906 PetscTryMethod(pc, "PCFieldSplitRestrictIS_C", (PC, IS), (pc, isy)); 1907 PetscFunctionReturn(PETSC_SUCCESS); 1908 } 1909 1910 static PetscErrorCode PCFieldSplitRestrictIS_FieldSplit(PC pc, IS isy) 1911 { 1912 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1913 PC_FieldSplitLink ilink = jac->head, next; 1914 PetscInt localsize, size, sizez, i; 1915 const PetscInt *ind, *indz; 1916 PetscInt *indc, *indcz; 1917 PetscBool flg; 1918 1919 PetscFunctionBegin; 1920 PetscCall(ISGetLocalSize(isy, &localsize)); 1921 PetscCallMPI(MPI_Scan(&localsize, &size, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)isy))); 1922 size -= localsize; 1923 while (ilink) { 1924 IS isrl, isr; 1925 PC subpc; 1926 PetscCall(ISEmbed(ilink->is, isy, PETSC_TRUE, &isrl)); 1927 PetscCall(ISGetLocalSize(isrl, &localsize)); 1928 PetscCall(PetscMalloc1(localsize, &indc)); 1929 PetscCall(ISGetIndices(isrl, &ind)); 1930 PetscCall(PetscArraycpy(indc, ind, localsize)); 1931 PetscCall(ISRestoreIndices(isrl, &ind)); 1932 PetscCall(ISDestroy(&isrl)); 1933 for (i = 0; i < localsize; i++) *(indc + i) += size; 1934 PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)isy), localsize, indc, PETSC_OWN_POINTER, &isr)); 1935 PetscCall(PetscObjectReference((PetscObject)isr)); 1936 PetscCall(ISDestroy(&ilink->is)); 1937 ilink->is = isr; 1938 PetscCall(PetscObjectReference((PetscObject)isr)); 1939 PetscCall(ISDestroy(&ilink->is_col)); 1940 ilink->is_col = isr; 1941 PetscCall(ISDestroy(&isr)); 1942 PetscCall(KSPGetPC(ilink->ksp, &subpc)); 1943 PetscCall(PetscObjectTypeCompare((PetscObject)subpc, PCFIELDSPLIT, &flg)); 1944 if (flg) { 1945 IS iszl, isz; 1946 MPI_Comm comm; 1947 PetscCall(ISGetLocalSize(ilink->is, &localsize)); 1948 comm = PetscObjectComm((PetscObject)ilink->is); 1949 PetscCall(ISEmbed(isy, ilink->is, PETSC_TRUE, &iszl)); 1950 PetscCallMPI(MPI_Scan(&localsize, &sizez, 1, MPIU_INT, MPI_SUM, comm)); 1951 sizez -= localsize; 1952 PetscCall(ISGetLocalSize(iszl, &localsize)); 1953 PetscCall(PetscMalloc1(localsize, &indcz)); 1954 PetscCall(ISGetIndices(iszl, &indz)); 1955 PetscCall(PetscArraycpy(indcz, indz, localsize)); 1956 PetscCall(ISRestoreIndices(iszl, &indz)); 1957 PetscCall(ISDestroy(&iszl)); 1958 for (i = 0; i < localsize; i++) *(indcz + i) += sizez; 1959 PetscCall(ISCreateGeneral(comm, localsize, indcz, PETSC_OWN_POINTER, &isz)); 1960 PetscCall(PCFieldSplitRestrictIS(subpc, isz)); 1961 PetscCall(ISDestroy(&isz)); 1962 } 1963 next = ilink->next; 1964 ilink = next; 1965 } 1966 jac->isrestrict = PETSC_TRUE; 1967 PetscFunctionReturn(PETSC_SUCCESS); 1968 } 1969 1970 static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc, const char splitname[], IS is) 1971 { 1972 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 1973 PC_FieldSplitLink ilink, next = jac->head; 1974 char prefix[128]; 1975 1976 PetscFunctionBegin; 1977 if (jac->splitdefined) { 1978 PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname)); 1979 PetscFunctionReturn(PETSC_SUCCESS); 1980 } 1981 PetscCall(PetscNew(&ilink)); 1982 if (splitname) { 1983 PetscCall(PetscStrallocpy(splitname, &ilink->splitname)); 1984 } else { 1985 PetscCall(PetscMalloc1(8, &ilink->splitname)); 1986 PetscCall(PetscSNPrintf(ilink->splitname, 7, "%" PetscInt_FMT, jac->nsplits)); 1987 } 1988 ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + jac->nsplits : KSP_Solve_FS_0 + 4; /* Any split great than 4 gets logged in the 4th split */ 1989 PetscCall(PetscObjectReference((PetscObject)is)); 1990 PetscCall(ISDestroy(&ilink->is)); 1991 ilink->is = is; 1992 PetscCall(PetscObjectReference((PetscObject)is)); 1993 PetscCall(ISDestroy(&ilink->is_col)); 1994 ilink->is_col = is; 1995 ilink->next = NULL; 1996 PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp)); 1997 PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel)); 1998 PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure)); 1999 PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1)); 2000 PetscCall(KSPSetType(ilink->ksp, KSPPREONLY)); 2001 2002 PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname)); 2003 PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix)); 2004 2005 if (!next) { 2006 jac->head = ilink; 2007 ilink->previous = NULL; 2008 } else { 2009 while (next->next) next = next->next; 2010 next->next = ilink; 2011 ilink->previous = next; 2012 } 2013 jac->nsplits++; 2014 PetscFunctionReturn(PETSC_SUCCESS); 2015 } 2016 2017 /*@C 2018 PCFieldSplitSetFields - Sets the fields that define one particular split in `PCFIELDSPLIT` 2019 2020 Logically Collective 2021 2022 Input Parameters: 2023 + pc - the preconditioner context 2024 . splitname - name of this split, if `NULL` the number of the split is used 2025 . n - the number of fields in this split 2026 . fields - the fields in this split 2027 - fields_col - generally the same as fields, if it does not match fields then the matrix block that is solved for this set of fields comes from an off-diagonal block 2028 of the matrix and fields_col provides the column indices for that block 2029 2030 Level: intermediate 2031 2032 Notes: 2033 Use `PCFieldSplitSetIS()` to set a general set of indices as a split. 2034 2035 `PCFieldSplitSetFields()` is for defining fields as strided blocks. For example, if the block 2036 size is three then one can define a split as 0, or 1 or 2 or 0,1 or 0,2 or 1,2 which mean 2037 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x1x3x5x7.. x12x45x78x.... 2038 where the numbered entries indicate what is in the split. 2039 2040 This function is called once per split (it creates a new split each time). Solve options 2041 for this split will be available under the prefix `-fieldsplit_SPLITNAME_`. 2042 2043 `PCFieldSplitSetIS()` does not support having a fields_col different from fields 2044 2045 Developer Notes: 2046 This routine does not actually create the `IS` representing the split, that is delayed 2047 until `PCSetUp_FieldSplit()`, because information about the vector/matrix layouts may not be 2048 available when this routine is called. 2049 2050 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetIS()`, `PCFieldSplitRestrictIS()` 2051 @*/ 2052 PetscErrorCode PCFieldSplitSetFields(PC pc, const char splitname[], PetscInt n, const PetscInt *fields, const PetscInt *fields_col) 2053 { 2054 PetscFunctionBegin; 2055 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2056 PetscAssertPointer(splitname, 2); 2057 PetscCheck(n >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Provided number of fields %" PetscInt_FMT " in split \"%s\" not positive", n, splitname); 2058 PetscAssertPointer(fields, 4); 2059 PetscTryMethod(pc, "PCFieldSplitSetFields_C", (PC, const char[], PetscInt, const PetscInt *, const PetscInt *), (pc, splitname, n, fields, fields_col)); 2060 PetscFunctionReturn(PETSC_SUCCESS); 2061 } 2062 2063 /*@ 2064 PCFieldSplitSetDiagUseAmat - set flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build 2065 the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators. 2066 2067 Logically Collective 2068 2069 Input Parameters: 2070 + pc - the preconditioner object 2071 - flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from 2072 2073 Options Database Key: 2074 . -pc_fieldsplit_diag_use_amat - use the Amat to provide the diagonal blocks 2075 2076 Level: intermediate 2077 2078 .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetDiagUseAmat()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFIELDSPLIT` 2079 @*/ 2080 PetscErrorCode PCFieldSplitSetDiagUseAmat(PC pc, PetscBool flg) 2081 { 2082 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2083 PetscBool isfs; 2084 2085 PetscFunctionBegin; 2086 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2087 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs)); 2088 PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT); 2089 jac->diag_use_amat = flg; 2090 PetscFunctionReturn(PETSC_SUCCESS); 2091 } 2092 2093 /*@ 2094 PCFieldSplitGetDiagUseAmat - get the flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build 2095 the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators. 2096 2097 Logically Collective 2098 2099 Input Parameter: 2100 . pc - the preconditioner object 2101 2102 Output Parameter: 2103 . flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from 2104 2105 Level: intermediate 2106 2107 .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetDiagUseAmat()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFIELDSPLIT` 2108 @*/ 2109 PetscErrorCode PCFieldSplitGetDiagUseAmat(PC pc, PetscBool *flg) 2110 { 2111 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2112 PetscBool isfs; 2113 2114 PetscFunctionBegin; 2115 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2116 PetscAssertPointer(flg, 2); 2117 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs)); 2118 PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT); 2119 *flg = jac->diag_use_amat; 2120 PetscFunctionReturn(PETSC_SUCCESS); 2121 } 2122 2123 /*@ 2124 PCFieldSplitSetOffDiagUseAmat - set flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build 2125 the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators. 2126 2127 Logically Collective 2128 2129 Input Parameters: 2130 + pc - the preconditioner object 2131 - flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from 2132 2133 Options Database Key: 2134 . -pc_fieldsplit_off_diag_use_amat <bool> - use the Amat to extract the off-diagonal blocks 2135 2136 Level: intermediate 2137 2138 .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFieldSplitSetDiagUseAmat()`, `PCFIELDSPLIT` 2139 @*/ 2140 PetscErrorCode PCFieldSplitSetOffDiagUseAmat(PC pc, PetscBool flg) 2141 { 2142 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2143 PetscBool isfs; 2144 2145 PetscFunctionBegin; 2146 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2147 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs)); 2148 PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT); 2149 jac->offdiag_use_amat = flg; 2150 PetscFunctionReturn(PETSC_SUCCESS); 2151 } 2152 2153 /*@ 2154 PCFieldSplitGetOffDiagUseAmat - get the flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build 2155 the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators. 2156 2157 Logically Collective 2158 2159 Input Parameter: 2160 . pc - the preconditioner object 2161 2162 Output Parameter: 2163 . flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from 2164 2165 Level: intermediate 2166 2167 .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFieldSplitGetDiagUseAmat()`, `PCFIELDSPLIT` 2168 @*/ 2169 PetscErrorCode PCFieldSplitGetOffDiagUseAmat(PC pc, PetscBool *flg) 2170 { 2171 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2172 PetscBool isfs; 2173 2174 PetscFunctionBegin; 2175 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2176 PetscAssertPointer(flg, 2); 2177 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs)); 2178 PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT); 2179 *flg = jac->offdiag_use_amat; 2180 PetscFunctionReturn(PETSC_SUCCESS); 2181 } 2182 2183 /*@C 2184 PCFieldSplitSetIS - Sets the exact elements for a split in a `PCFIELDSPLIT` 2185 2186 Logically Collective 2187 2188 Input Parameters: 2189 + pc - the preconditioner context 2190 . splitname - name of this split, if `NULL` the number of the split is used 2191 - is - the index set that defines the elements in this split 2192 2193 Level: intermediate 2194 2195 Notes: 2196 Use `PCFieldSplitSetFields()`, for splits defined by strided types. 2197 2198 This function is called once per split (it creates a new split each time). Solve options 2199 for this split will be available under the prefix -fieldsplit_SPLITNAME_. 2200 2201 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()` 2202 @*/ 2203 PetscErrorCode PCFieldSplitSetIS(PC pc, const char splitname[], IS is) 2204 { 2205 PetscFunctionBegin; 2206 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2207 if (splitname) PetscAssertPointer(splitname, 2); 2208 PetscValidHeaderSpecific(is, IS_CLASSID, 3); 2209 PetscTryMethod(pc, "PCFieldSplitSetIS_C", (PC, const char[], IS), (pc, splitname, is)); 2210 PetscFunctionReturn(PETSC_SUCCESS); 2211 } 2212 2213 /*@C 2214 PCFieldSplitGetIS - Retrieves the elements for a split as an `IS` 2215 2216 Logically Collective 2217 2218 Input Parameters: 2219 + pc - the preconditioner context 2220 - splitname - name of this split 2221 2222 Output Parameter: 2223 . is - the index set that defines the elements in this split, or `NULL` if the split is not found 2224 2225 Level: intermediate 2226 2227 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetIS()` 2228 @*/ 2229 PetscErrorCode PCFieldSplitGetIS(PC pc, const char splitname[], IS *is) 2230 { 2231 PetscFunctionBegin; 2232 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2233 PetscAssertPointer(splitname, 2); 2234 PetscAssertPointer(is, 3); 2235 { 2236 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2237 PC_FieldSplitLink ilink = jac->head; 2238 PetscBool found; 2239 2240 *is = NULL; 2241 while (ilink) { 2242 PetscCall(PetscStrcmp(ilink->splitname, splitname, &found)); 2243 if (found) { 2244 *is = ilink->is; 2245 break; 2246 } 2247 ilink = ilink->next; 2248 } 2249 } 2250 PetscFunctionReturn(PETSC_SUCCESS); 2251 } 2252 2253 /*@C 2254 PCFieldSplitGetISByIndex - Retrieves the elements for a given split as an `IS` 2255 2256 Logically Collective 2257 2258 Input Parameters: 2259 + pc - the preconditioner context 2260 - index - index of this split 2261 2262 Output Parameter: 2263 . is - the index set that defines the elements in this split 2264 2265 Level: intermediate 2266 2267 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitGetIS()`, `PCFieldSplitSetIS()` 2268 @*/ 2269 PetscErrorCode PCFieldSplitGetISByIndex(PC pc, PetscInt index, IS *is) 2270 { 2271 PetscFunctionBegin; 2272 PetscCheck(index >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", index); 2273 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2274 PetscAssertPointer(is, 3); 2275 { 2276 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2277 PC_FieldSplitLink ilink = jac->head; 2278 PetscInt i = 0; 2279 PetscCheck(index < jac->nsplits, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " requested but only %" PetscInt_FMT " exist", index, jac->nsplits); 2280 2281 while (i < index) { 2282 ilink = ilink->next; 2283 ++i; 2284 } 2285 PetscCall(PCFieldSplitGetIS(pc, ilink->splitname, is)); 2286 } 2287 PetscFunctionReturn(PETSC_SUCCESS); 2288 } 2289 2290 /*@ 2291 PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the 2292 fieldsplit preconditioner when calling `PCFieldSplitSetIS()`. If not set the matrix block size is used. 2293 2294 Logically Collective 2295 2296 Input Parameters: 2297 + pc - the preconditioner context 2298 - bs - the block size 2299 2300 Level: intermediate 2301 2302 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()` 2303 @*/ 2304 PetscErrorCode PCFieldSplitSetBlockSize(PC pc, PetscInt bs) 2305 { 2306 PetscFunctionBegin; 2307 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2308 PetscValidLogicalCollectiveInt(pc, bs, 2); 2309 PetscTryMethod(pc, "PCFieldSplitSetBlockSize_C", (PC, PetscInt), (pc, bs)); 2310 PetscFunctionReturn(PETSC_SUCCESS); 2311 } 2312 2313 /*@C 2314 PCFieldSplitGetSubKSP - Gets the `KSP` contexts for all splits 2315 2316 Collective 2317 2318 Input Parameter: 2319 . pc - the preconditioner context 2320 2321 Output Parameters: 2322 + n - the number of splits 2323 - subksp - the array of `KSP` contexts 2324 2325 Level: advanced 2326 2327 Notes: 2328 After `PCFieldSplitGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()` 2329 (not the `KSP`, just the array that contains them). 2330 2331 You must call `PCSetUp()` before calling `PCFieldSplitGetSubKSP()`. 2332 2333 If the fieldsplit is of type `PC_COMPOSITE_SCHUR`, it returns the `KSP` object used inside the 2334 Schur complement and the `KSP` object used to iterate over the Schur complement. 2335 To access all the `KSP` objects used in `PC_COMPOSITE_SCHUR`, use `PCFieldSplitSchurGetSubKSP()`. 2336 2337 If the fieldsplit is of type `PC_COMPOSITE_GKB`, it returns the `KSP` object used to solve the 2338 inner linear system defined by the matrix H in each loop. 2339 2340 Fortran Notes: 2341 You must pass in a `KSP` array that is large enough to contain all the `KSP`s. 2342 You can call `PCFieldSplitGetSubKSP`(pc,n,`PETSC_NULL_KSP`,ierr) to determine how large the 2343 `KSP` array must be. 2344 2345 Developer Notes: 2346 There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()` 2347 2348 The Fortran interface should be modernized to return directly the array of values. 2349 2350 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitSchurGetSubKSP()` 2351 @*/ 2352 PetscErrorCode PCFieldSplitGetSubKSP(PC pc, PetscInt *n, KSP *subksp[]) 2353 { 2354 PetscFunctionBegin; 2355 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2356 if (n) PetscAssertPointer(n, 2); 2357 PetscUseMethod(pc, "PCFieldSplitGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp)); 2358 PetscFunctionReturn(PETSC_SUCCESS); 2359 } 2360 2361 /*@C 2362 PCFieldSplitSchurGetSubKSP - Gets the `KSP` contexts used inside the Schur complement based `PCFIELDSPLIT` 2363 2364 Collective 2365 2366 Input Parameter: 2367 . pc - the preconditioner context 2368 2369 Output Parameters: 2370 + n - the number of splits 2371 - subksp - the array of `KSP` contexts 2372 2373 Level: advanced 2374 2375 Notes: 2376 After `PCFieldSplitSchurGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()` 2377 (not the `KSP` just the array that contains them). 2378 2379 You must call `PCSetUp()` before calling `PCFieldSplitSchurGetSubKSP()`. 2380 2381 If the fieldsplit type is of type `PC_COMPOSITE_SCHUR`, it returns (in order) 2382 + 1 - the `KSP` used for the (1,1) block 2383 . 2 - the `KSP` used for the Schur complement (not the one used for the interior Schur solver) 2384 - 3 - the `KSP` used for the (1,1) block in the upper triangular factor (if different from that of the (1,1) block). 2385 2386 It returns a null array if the fieldsplit is not of type `PC_COMPOSITE_SCHUR`; in this case, you should use `PCFieldSplitGetSubKSP()`. 2387 2388 Fortran Notes: 2389 You must pass in a `KSP` array that is large enough to contain all the local `KSP`s. 2390 You can call `PCFieldSplitSchurGetSubKSP`(pc,n,`PETSC_NULL_KSP`,ierr) to determine how large the 2391 `KSP` array must be. 2392 2393 Developer Notes: 2394 There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()` 2395 2396 Should the functionality of `PCFieldSplitSchurGetSubKSP()` and `PCFieldSplitGetSubKSP()` be merged? 2397 2398 The Fortran interface should be modernized to return directly the array of values. 2399 2400 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitGetSubKSP()` 2401 @*/ 2402 PetscErrorCode PCFieldSplitSchurGetSubKSP(PC pc, PetscInt *n, KSP *subksp[]) 2403 { 2404 PetscFunctionBegin; 2405 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2406 if (n) PetscAssertPointer(n, 2); 2407 PetscUseMethod(pc, "PCFieldSplitSchurGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp)); 2408 PetscFunctionReturn(PETSC_SUCCESS); 2409 } 2410 2411 /*@ 2412 PCFieldSplitSetSchurPre - Indicates from what operator the preconditioner is constructed for the Schur complement. 2413 The default is the A11 matrix. 2414 2415 Collective 2416 2417 Input Parameters: 2418 + pc - the preconditioner context 2419 . ptype - which matrix to use for preconditioning the Schur complement: `PC_FIELDSPLIT_SCHUR_PRE_A11` (default), 2420 `PC_FIELDSPLIT_SCHUR_PRE_SELF`, `PC_FIELDSPLIT_SCHUR_PRE_USER`, 2421 `PC_FIELDSPLIT_SCHUR_PRE_SELFP`, and `PC_FIELDSPLIT_SCHUR_PRE_FULL` 2422 - pre - matrix to use for preconditioning, or `NULL` 2423 2424 Options Database Keys: 2425 + -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is `a11`. See notes for meaning of various arguments 2426 - -fieldsplit_1_pc_type <pctype> - the preconditioner algorithm that is used to construct the preconditioner from the operator 2427 2428 Level: intermediate 2429 2430 Notes: 2431 If ptype is 2432 + a11 - the preconditioner for the Schur complement is generated from the block diagonal part of the preconditioner 2433 matrix associated with the Schur complement (i.e. A11), not the Schur complement matrix 2434 . self - the preconditioner for the Schur complement is generated from the symbolic representation of the Schur complement matrix: 2435 The only preconditioner that currently works with this symbolic representation matrix object is the `PCLSC` 2436 preconditioner 2437 . user - the preconditioner for the Schur complement is generated from the user provided matrix (pre argument 2438 to this function). 2439 . selfp - the preconditioning for the Schur complement is generated from an explicitly-assembled approximation Sp = A11 - A10 inv(diag(A00)) A01 2440 This is only a good preconditioner when diag(A00) is a good preconditioner for A00. Optionally, A00 can be 2441 lumped before extracting the diagonal using the additional option `-fieldsplit_1_mat_schur_complement_ainv_type lump` 2442 - full - the preconditioner for the Schur complement is generated from the exact Schur complement matrix representation 2443 computed internally by `PCFIELDSPLIT` (this is expensive) 2444 useful mostly as a test that the Schur complement approach can work for your problem 2445 2446 When solving a saddle point problem, where the A11 block is identically zero, using `a11` as the ptype only makes sense 2447 with the additional option `-fieldsplit_1_pc_type none`. Usually for saddle point problems one would use a ptype of self and 2448 `-fieldsplit_1_pc_type lsc` which uses the least squares commutator to compute a preconditioner for the Schur complement. 2449 2450 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, 2451 `MatSchurComplementSetAinvType()`, `PCLSC`, 2452 2453 @*/ 2454 PetscErrorCode PCFieldSplitSetSchurPre(PC pc, PCFieldSplitSchurPreType ptype, Mat pre) 2455 { 2456 PetscFunctionBegin; 2457 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2458 PetscTryMethod(pc, "PCFieldSplitSetSchurPre_C", (PC, PCFieldSplitSchurPreType, Mat), (pc, ptype, pre)); 2459 PetscFunctionReturn(PETSC_SUCCESS); 2460 } 2461 2462 PetscErrorCode PCFieldSplitSchurPrecondition(PC pc, PCFieldSplitSchurPreType ptype, Mat pre) 2463 { 2464 return PCFieldSplitSetSchurPre(pc, ptype, pre); 2465 } /* Deprecated name */ 2466 2467 /*@ 2468 PCFieldSplitGetSchurPre - For Schur complement fieldsplit, determine how the Schur complement will be 2469 preconditioned. See `PCFieldSplitSetSchurPre()` for details. 2470 2471 Logically Collective 2472 2473 Input Parameter: 2474 . pc - the preconditioner context 2475 2476 Output Parameters: 2477 + ptype - which matrix to use for preconditioning the Schur complement: `PC_FIELDSPLIT_SCHUR_PRE_A11`, `PC_FIELDSPLIT_SCHUR_PRE_SELF`, `PC_FIELDSPLIT_SCHUR_PRE_USER` 2478 - pre - matrix to use for preconditioning (with `PC_FIELDSPLIT_SCHUR_PRE_USER`), or `NULL` 2479 2480 Level: intermediate 2481 2482 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCLSC` 2483 2484 @*/ 2485 PetscErrorCode PCFieldSplitGetSchurPre(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre) 2486 { 2487 PetscFunctionBegin; 2488 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2489 PetscUseMethod(pc, "PCFieldSplitGetSchurPre_C", (PC, PCFieldSplitSchurPreType *, Mat *), (pc, ptype, pre)); 2490 PetscFunctionReturn(PETSC_SUCCESS); 2491 } 2492 2493 /*@ 2494 PCFieldSplitSchurGetS - extract the `MATSCHURCOMPLEMENT` object used by this `PCFIELDSPLIT` in case it needs to be configured separately 2495 2496 Not Collective 2497 2498 Input Parameter: 2499 . pc - the preconditioner context 2500 2501 Output Parameter: 2502 . S - the Schur complement matrix 2503 2504 Level: advanced 2505 2506 Note: 2507 This matrix should not be destroyed using `MatDestroy()`; rather, use `PCFieldSplitSchurRestoreS()`. 2508 2509 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MATSCHURCOMPLEMENT`, `PCFieldSplitSchurRestoreS()`, 2510 `MatCreateSchurComplement()`, `MatSchurComplementGetKSP()`, `MatSchurComplementComputeExplicitOperator()`, `MatGetSchurComplement()` 2511 @*/ 2512 PetscErrorCode PCFieldSplitSchurGetS(PC pc, Mat *S) 2513 { 2514 const char *t; 2515 PetscBool isfs; 2516 PC_FieldSplit *jac; 2517 2518 PetscFunctionBegin; 2519 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2520 PetscCall(PetscObjectGetType((PetscObject)pc, &t)); 2521 PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs)); 2522 PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t); 2523 jac = (PC_FieldSplit *)pc->data; 2524 PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type); 2525 if (S) *S = jac->schur; 2526 PetscFunctionReturn(PETSC_SUCCESS); 2527 } 2528 2529 /*@ 2530 PCFieldSplitSchurRestoreS - returns the `MATSCHURCOMPLEMENT` matrix used by this `PC` 2531 2532 Not Collective 2533 2534 Input Parameters: 2535 + pc - the preconditioner context 2536 - S - the Schur complement matrix 2537 2538 Level: advanced 2539 2540 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MatSchurComplement`, `PCFieldSplitSchurGetS()` 2541 @*/ 2542 PetscErrorCode PCFieldSplitSchurRestoreS(PC pc, Mat *S) 2543 { 2544 const char *t; 2545 PetscBool isfs; 2546 PC_FieldSplit *jac; 2547 2548 PetscFunctionBegin; 2549 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2550 PetscCall(PetscObjectGetType((PetscObject)pc, &t)); 2551 PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs)); 2552 PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t); 2553 jac = (PC_FieldSplit *)pc->data; 2554 PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type); 2555 PetscCheck(S && (*S == jac->schur), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MatSchurComplement restored is not the same as gotten"); 2556 PetscFunctionReturn(PETSC_SUCCESS); 2557 } 2558 2559 static PetscErrorCode PCFieldSplitSetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType ptype, Mat pre) 2560 { 2561 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2562 2563 PetscFunctionBegin; 2564 jac->schurpre = ptype; 2565 if (ptype == PC_FIELDSPLIT_SCHUR_PRE_USER && pre) { 2566 PetscCall(MatDestroy(&jac->schur_user)); 2567 jac->schur_user = pre; 2568 PetscCall(PetscObjectReference((PetscObject)jac->schur_user)); 2569 } 2570 PetscFunctionReturn(PETSC_SUCCESS); 2571 } 2572 2573 static PetscErrorCode PCFieldSplitGetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre) 2574 { 2575 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2576 2577 PetscFunctionBegin; 2578 if (ptype) *ptype = jac->schurpre; 2579 if (pre) *pre = jac->schur_user; 2580 PetscFunctionReturn(PETSC_SUCCESS); 2581 } 2582 2583 /*@ 2584 PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain in the preconditioner {cite}`murphy2000note` and {cite}`ipsen2001note` 2585 2586 Collective 2587 2588 Input Parameters: 2589 + pc - the preconditioner context 2590 - ftype - which blocks of factorization to retain, `PC_FIELDSPLIT_SCHUR_FACT_FULL` is default 2591 2592 Options Database Key: 2593 . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> - default is `full` 2594 2595 Level: intermediate 2596 2597 Notes: 2598 The FULL factorization is 2599 .vb 2600 (A B) = (1 0) (A 0) (1 Ainv*B) = L D U 2601 (C E) (C*Ainv 1) (0 S) (0 1) 2602 .vb 2603 where S = E - 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 $L*D$, 2604 and DIAG is the diagonal part with the sign of S flipped (because this makes the preconditioner positive definite for many formulations, 2605 thus allowing the use of `KSPMINRES)`. Sign flipping of S can be turned off with `PCFieldSplitSetSchurScale()`. 2606 2607 If A and S are solved exactly 2608 .vb 2609 *) FULL factorization is a direct solver. 2610 *) The preconditioned operator with LOWER or UPPER has all eigenvalues equal to 1 and minimal polynomial of degree 2, so `KSPGMRES` converges in 2 iterations. 2611 *) With DIAG, the preconditioned operator has three distinct nonzero eigenvalues and minimal polynomial of degree at most 4, so `KSPGMRES` converges in at most 4 iterations. 2612 .ve 2613 2614 If the iteration count is very low, consider using `KSPFGMRES` or `KSPGCR` which can use one less preconditioner 2615 application in this case. Note that the preconditioned operator may be highly non-normal, so such fast convergence may not be observed in practice. 2616 2617 For symmetric problems in which A is positive definite and S is negative definite, DIAG can be used with `KSPMINRES`. 2618 2619 A flexible method like `KSPFGMRES` or `KSPGCR`, [](sec_flexibleksp), must be used if the fieldsplit preconditioner is nonlinear (e.g. a few iterations of a Krylov method is used to solve with A or S). 2620 2621 .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurScale()`, 2622 [](sec_flexibleksp) 2623 @*/ 2624 PetscErrorCode PCFieldSplitSetSchurFactType(PC pc, PCFieldSplitSchurFactType ftype) 2625 { 2626 PetscFunctionBegin; 2627 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2628 PetscTryMethod(pc, "PCFieldSplitSetSchurFactType_C", (PC, PCFieldSplitSchurFactType), (pc, ftype)); 2629 PetscFunctionReturn(PETSC_SUCCESS); 2630 } 2631 2632 static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc, PCFieldSplitSchurFactType ftype) 2633 { 2634 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2635 2636 PetscFunctionBegin; 2637 jac->schurfactorization = ftype; 2638 PetscFunctionReturn(PETSC_SUCCESS); 2639 } 2640 2641 /*@ 2642 PCFieldSplitSetSchurScale - Controls the sign flip of S for `PC_FIELDSPLIT_SCHUR_FACT_DIAG`. 2643 2644 Collective 2645 2646 Input Parameters: 2647 + pc - the preconditioner context 2648 - scale - scaling factor for the Schur complement 2649 2650 Options Database Key: 2651 . -pc_fieldsplit_schur_scale <scale> - default is -1.0 2652 2653 Level: intermediate 2654 2655 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurFactType`, `PCFieldSplitSetSchurFactType()` 2656 @*/ 2657 PetscErrorCode PCFieldSplitSetSchurScale(PC pc, PetscScalar scale) 2658 { 2659 PetscFunctionBegin; 2660 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2661 PetscValidLogicalCollectiveScalar(pc, scale, 2); 2662 PetscTryMethod(pc, "PCFieldSplitSetSchurScale_C", (PC, PetscScalar), (pc, scale)); 2663 PetscFunctionReturn(PETSC_SUCCESS); 2664 } 2665 2666 static PetscErrorCode PCFieldSplitSetSchurScale_FieldSplit(PC pc, PetscScalar scale) 2667 { 2668 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2669 2670 PetscFunctionBegin; 2671 jac->schurscale = scale; 2672 PetscFunctionReturn(PETSC_SUCCESS); 2673 } 2674 2675 /*@C 2676 PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement 2677 2678 Collective 2679 2680 Input Parameter: 2681 . pc - the preconditioner context 2682 2683 Output Parameters: 2684 + A00 - the (0,0) block 2685 . A01 - the (0,1) block 2686 . A10 - the (1,0) block 2687 - A11 - the (1,1) block 2688 2689 Level: advanced 2690 2691 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `MatSchurComplementGetSubMatrices()`, `MatSchurComplementSetSubMatrices()` 2692 @*/ 2693 PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc, Mat *A00, Mat *A01, Mat *A10, Mat *A11) 2694 { 2695 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2696 2697 PetscFunctionBegin; 2698 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2699 PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach."); 2700 if (A00) *A00 = jac->pmat[0]; 2701 if (A01) *A01 = jac->B; 2702 if (A10) *A10 = jac->C; 2703 if (A11) *A11 = jac->pmat[1]; 2704 PetscFunctionReturn(PETSC_SUCCESS); 2705 } 2706 2707 /*@ 2708 PCFieldSplitSetGKBTol - Sets the solver tolerance for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT` 2709 2710 Collective 2711 2712 Input Parameters: 2713 + pc - the preconditioner context 2714 - tolerance - the solver tolerance 2715 2716 Options Database Key: 2717 . -pc_fieldsplit_gkb_tol <tolerance> - default is 1e-5 2718 2719 Level: intermediate 2720 2721 Note: 2722 The generalized GKB algorithm {cite}`arioli2013` uses a lower bound estimate of the error in energy norm as stopping criterion. 2723 It stops once the lower bound estimate undershoots the required solver tolerance. Although the actual error might be bigger than 2724 this estimate, the stopping criterion is satisfactory in practical cases. 2725 2726 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBMaxit()` 2727 @*/ 2728 PetscErrorCode PCFieldSplitSetGKBTol(PC pc, PetscReal tolerance) 2729 { 2730 PetscFunctionBegin; 2731 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2732 PetscValidLogicalCollectiveReal(pc, tolerance, 2); 2733 PetscTryMethod(pc, "PCFieldSplitSetGKBTol_C", (PC, PetscReal), (pc, tolerance)); 2734 PetscFunctionReturn(PETSC_SUCCESS); 2735 } 2736 2737 static PetscErrorCode PCFieldSplitSetGKBTol_FieldSplit(PC pc, PetscReal tolerance) 2738 { 2739 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2740 2741 PetscFunctionBegin; 2742 jac->gkbtol = tolerance; 2743 PetscFunctionReturn(PETSC_SUCCESS); 2744 } 2745 2746 /*@ 2747 PCFieldSplitSetGKBMaxit - Sets the maximum number of iterations for the generalized Golub-Kahan bidiagonalization preconditioner in `PCFIELDSPLIT` 2748 2749 Collective 2750 2751 Input Parameters: 2752 + pc - the preconditioner context 2753 - maxit - the maximum number of iterations 2754 2755 Options Database Key: 2756 . -pc_fieldsplit_gkb_maxit <maxit> - default is 100 2757 2758 Level: intermediate 2759 2760 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBNu()` 2761 @*/ 2762 PetscErrorCode PCFieldSplitSetGKBMaxit(PC pc, PetscInt maxit) 2763 { 2764 PetscFunctionBegin; 2765 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2766 PetscValidLogicalCollectiveInt(pc, maxit, 2); 2767 PetscTryMethod(pc, "PCFieldSplitSetGKBMaxit_C", (PC, PetscInt), (pc, maxit)); 2768 PetscFunctionReturn(PETSC_SUCCESS); 2769 } 2770 2771 static PetscErrorCode PCFieldSplitSetGKBMaxit_FieldSplit(PC pc, PetscInt maxit) 2772 { 2773 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2774 2775 PetscFunctionBegin; 2776 jac->gkbmaxit = maxit; 2777 PetscFunctionReturn(PETSC_SUCCESS); 2778 } 2779 2780 /*@ 2781 PCFieldSplitSetGKBDelay - Sets the delay in the lower bound error estimate in the generalized Golub-Kahan bidiagonalization {cite}`arioli2013` in `PCFIELDSPLIT` 2782 preconditioner. 2783 2784 Collective 2785 2786 Input Parameters: 2787 + pc - the preconditioner context 2788 - delay - the delay window in the lower bound estimate 2789 2790 Options Database Key: 2791 . -pc_fieldsplit_gkb_delay <delay> - default is 5 2792 2793 Level: intermediate 2794 2795 Notes: 2796 The algorithm uses a lower bound estimate of the error in energy norm as stopping criterion. The lower bound of the error $ ||u-u^k||_H $ 2797 is expressed as a truncated sum. The error at iteration k can only be measured at iteration (k + `delay`), and thus the algorithm needs 2798 at least (`delay` + 1) iterations to stop. 2799 2800 For more details on the generalized Golub-Kahan bidiagonalization method and its lower bound stopping criterion, please refer to {cite}`arioli2013` 2801 2802 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()` 2803 @*/ 2804 PetscErrorCode PCFieldSplitSetGKBDelay(PC pc, PetscInt delay) 2805 { 2806 PetscFunctionBegin; 2807 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2808 PetscValidLogicalCollectiveInt(pc, delay, 2); 2809 PetscTryMethod(pc, "PCFieldSplitSetGKBDelay_C", (PC, PetscInt), (pc, delay)); 2810 PetscFunctionReturn(PETSC_SUCCESS); 2811 } 2812 2813 static PetscErrorCode PCFieldSplitSetGKBDelay_FieldSplit(PC pc, PetscInt delay) 2814 { 2815 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2816 2817 PetscFunctionBegin; 2818 jac->gkbdelay = delay; 2819 PetscFunctionReturn(PETSC_SUCCESS); 2820 } 2821 2822 /*@ 2823 PCFieldSplitSetGKBNu - Sets the scalar value nu >= 0 in the transformation H = A00 + nu*A01*A01' of the (1,1) block in the 2824 Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT` 2825 2826 Collective 2827 2828 Input Parameters: 2829 + pc - the preconditioner context 2830 - nu - the shift parameter 2831 2832 Options Database Key: 2833 . -pc_fieldsplit_gkb_nu <nu> - default is 1 2834 2835 Level: intermediate 2836 2837 Notes: 2838 This shift is in general done to obtain better convergence properties for the outer loop of the algorithm. This is often achieved by choosing `nu` sufficiently large. However, 2839 if `nu` is chosen too large, the matrix H might be badly conditioned and the solution of the linear system $Hx = b$ in the inner loop becomes difficult. It is therefore 2840 necessary to find a good balance in between the convergence of the inner and outer loop. 2841 2842 For `nu` = 0, no shift is done. In this case A00 has to be positive definite. The matrix N in {cite}`arioli2013` is then chosen as identity. 2843 2844 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()` 2845 @*/ 2846 PetscErrorCode PCFieldSplitSetGKBNu(PC pc, PetscReal nu) 2847 { 2848 PetscFunctionBegin; 2849 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2850 PetscValidLogicalCollectiveReal(pc, nu, 2); 2851 PetscTryMethod(pc, "PCFieldSplitSetGKBNu_C", (PC, PetscReal), (pc, nu)); 2852 PetscFunctionReturn(PETSC_SUCCESS); 2853 } 2854 2855 static PetscErrorCode PCFieldSplitSetGKBNu_FieldSplit(PC pc, PetscReal nu) 2856 { 2857 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2858 2859 PetscFunctionBegin; 2860 jac->gkbnu = nu; 2861 PetscFunctionReturn(PETSC_SUCCESS); 2862 } 2863 2864 static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc, PCCompositeType type) 2865 { 2866 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2867 2868 PetscFunctionBegin; 2869 jac->type = type; 2870 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL)); 2871 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL)); 2872 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL)); 2873 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL)); 2874 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL)); 2875 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL)); 2876 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL)); 2877 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL)); 2878 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL)); 2879 2880 if (type == PC_COMPOSITE_SCHUR) { 2881 pc->ops->apply = PCApply_FieldSplit_Schur; 2882 pc->ops->applytranspose = PCApplyTranspose_FieldSplit_Schur; 2883 pc->ops->view = PCView_FieldSplit_Schur; 2884 2885 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit_Schur)); 2886 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", PCFieldSplitSetSchurPre_FieldSplit)); 2887 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", PCFieldSplitGetSchurPre_FieldSplit)); 2888 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", PCFieldSplitSetSchurFactType_FieldSplit)); 2889 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", PCFieldSplitSetSchurScale_FieldSplit)); 2890 } else if (type == PC_COMPOSITE_GKB) { 2891 pc->ops->apply = PCApply_FieldSplit_GKB; 2892 pc->ops->view = PCView_FieldSplit_GKB; 2893 2894 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit)); 2895 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", PCFieldSplitSetGKBTol_FieldSplit)); 2896 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", PCFieldSplitSetGKBMaxit_FieldSplit)); 2897 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", PCFieldSplitSetGKBNu_FieldSplit)); 2898 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", PCFieldSplitSetGKBDelay_FieldSplit)); 2899 } else { 2900 pc->ops->apply = PCApply_FieldSplit; 2901 pc->ops->view = PCView_FieldSplit; 2902 2903 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit)); 2904 } 2905 PetscFunctionReturn(PETSC_SUCCESS); 2906 } 2907 2908 static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc, PetscInt bs) 2909 { 2910 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2911 2912 PetscFunctionBegin; 2913 PetscCheck(bs >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Blocksize must be positive, you gave %" PetscInt_FMT, bs); 2914 PetscCheck(jac->bs <= 0 || jac->bs == bs, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Cannot change fieldsplit blocksize from %" PetscInt_FMT " to %" PetscInt_FMT " after it has been set", jac->bs, bs); 2915 jac->bs = bs; 2916 PetscFunctionReturn(PETSC_SUCCESS); 2917 } 2918 2919 static PetscErrorCode PCSetCoordinates_FieldSplit(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[]) 2920 { 2921 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2922 PC_FieldSplitLink ilink_current = jac->head; 2923 IS is_owned; 2924 2925 PetscFunctionBegin; 2926 jac->coordinates_set = PETSC_TRUE; // Internal flag 2927 PetscCall(MatGetOwnershipIS(pc->mat, &is_owned, NULL)); 2928 2929 while (ilink_current) { 2930 // For each IS, embed it to get local coords indces 2931 IS is_coords; 2932 PetscInt ndofs_block; 2933 const PetscInt *block_dofs_enumeration; // Numbering of the dofs relevant to the current block 2934 2935 // Setting drop to true for safety. It should make no difference. 2936 PetscCall(ISEmbed(ilink_current->is, is_owned, PETSC_TRUE, &is_coords)); 2937 PetscCall(ISGetLocalSize(is_coords, &ndofs_block)); 2938 PetscCall(ISGetIndices(is_coords, &block_dofs_enumeration)); 2939 2940 // Allocate coordinates vector and set it directly 2941 PetscCall(PetscMalloc1(ndofs_block * dim, &(ilink_current->coords))); 2942 for (PetscInt dof = 0; dof < ndofs_block; ++dof) { 2943 for (PetscInt d = 0; d < dim; ++d) (ilink_current->coords)[dim * dof + d] = coords[dim * block_dofs_enumeration[dof] + d]; 2944 } 2945 ilink_current->dim = dim; 2946 ilink_current->ndofs = ndofs_block; 2947 PetscCall(ISRestoreIndices(is_coords, &block_dofs_enumeration)); 2948 PetscCall(ISDestroy(&is_coords)); 2949 ilink_current = ilink_current->next; 2950 } 2951 PetscCall(ISDestroy(&is_owned)); 2952 PetscFunctionReturn(PETSC_SUCCESS); 2953 } 2954 2955 /*@ 2956 PCFieldSplitSetType - Sets the type, `PCCompositeType`, of a `PCFIELDSPLIT` 2957 2958 Collective 2959 2960 Input Parameters: 2961 + pc - the preconditioner context 2962 - type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR` 2963 2964 Options Database Key: 2965 . -pc_fieldsplit_type <one of multiplicative, additive, symmetric_multiplicative, special, schur> - Sets fieldsplit preconditioner type 2966 2967 Level: intermediate 2968 2969 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCCompositeType`, `PCCompositeGetType()`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`, 2970 `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR` 2971 @*/ 2972 PetscErrorCode PCFieldSplitSetType(PC pc, PCCompositeType type) 2973 { 2974 PetscFunctionBegin; 2975 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 2976 PetscTryMethod(pc, "PCFieldSplitSetType_C", (PC, PCCompositeType), (pc, type)); 2977 PetscFunctionReturn(PETSC_SUCCESS); 2978 } 2979 2980 /*@ 2981 PCFieldSplitGetType - Gets the type, `PCCompositeType`, of a `PCFIELDSPLIT` 2982 2983 Not collective 2984 2985 Input Parameter: 2986 . pc - the preconditioner context 2987 2988 Output Parameter: 2989 . type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR` 2990 2991 Level: intermediate 2992 2993 .seealso: [](sec_block_matrices), `PC`, `PCCompositeSetType()`, `PCFIELDSPLIT`, `PCCompositeType`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`, 2994 `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR` 2995 @*/ 2996 PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type) 2997 { 2998 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 2999 3000 PetscFunctionBegin; 3001 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 3002 PetscAssertPointer(type, 2); 3003 *type = jac->type; 3004 PetscFunctionReturn(PETSC_SUCCESS); 3005 } 3006 3007 /*@ 3008 PCFieldSplitSetDMSplits - Flags whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible. 3009 3010 Logically Collective 3011 3012 Input Parameters: 3013 + pc - the preconditioner context 3014 - flg - boolean indicating whether to use field splits defined by the `DM` 3015 3016 Options Database Key: 3017 . -pc_fieldsplit_dm_splits <bool> - use the field splits defined by the `DM` 3018 3019 Level: intermediate 3020 3021 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDMSplits()`, `PCFieldSplitSetFields()`, `PCFieldsplitSetIS()` 3022 @*/ 3023 PetscErrorCode PCFieldSplitSetDMSplits(PC pc, PetscBool flg) 3024 { 3025 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 3026 PetscBool isfs; 3027 3028 PetscFunctionBegin; 3029 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 3030 PetscValidLogicalCollectiveBool(pc, flg, 2); 3031 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs)); 3032 if (isfs) jac->dm_splits = flg; 3033 PetscFunctionReturn(PETSC_SUCCESS); 3034 } 3035 3036 /*@ 3037 PCFieldSplitGetDMSplits - Returns flag indicating whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible. 3038 3039 Logically Collective 3040 3041 Input Parameter: 3042 . pc - the preconditioner context 3043 3044 Output Parameter: 3045 . flg - boolean indicating whether to use field splits defined by the `DM` 3046 3047 Level: intermediate 3048 3049 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDMSplits()`, `PCFieldSplitSetFields()`, `PCFieldsplitSetIS()` 3050 @*/ 3051 PetscErrorCode PCFieldSplitGetDMSplits(PC pc, PetscBool *flg) 3052 { 3053 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 3054 PetscBool isfs; 3055 3056 PetscFunctionBegin; 3057 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 3058 PetscAssertPointer(flg, 2); 3059 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs)); 3060 if (isfs) { 3061 if (flg) *flg = jac->dm_splits; 3062 } 3063 PetscFunctionReturn(PETSC_SUCCESS); 3064 } 3065 3066 /*@ 3067 PCFieldSplitGetDetectSaddlePoint - Returns flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries. 3068 3069 Logically Collective 3070 3071 Input Parameter: 3072 . pc - the preconditioner context 3073 3074 Output Parameter: 3075 . flg - boolean indicating whether to detect fields or not 3076 3077 Level: intermediate 3078 3079 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDetectSaddlePoint()` 3080 @*/ 3081 PetscErrorCode PCFieldSplitGetDetectSaddlePoint(PC pc, PetscBool *flg) 3082 { 3083 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 3084 3085 PetscFunctionBegin; 3086 *flg = jac->detect; 3087 PetscFunctionReturn(PETSC_SUCCESS); 3088 } 3089 3090 /*@ 3091 PCFieldSplitSetDetectSaddlePoint - Sets flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries. 3092 3093 Logically Collective 3094 3095 Input Parameter: 3096 . pc - the preconditioner context 3097 3098 Output Parameter: 3099 . flg - boolean indicating whether to detect fields or not 3100 3101 Options Database Key: 3102 . -pc_fieldsplit_detect_saddle_point <bool> - detect and use the saddle point 3103 3104 Level: intermediate 3105 3106 Note: 3107 Also sets the split type to `PC_COMPOSITE_SCHUR` (see `PCFieldSplitSetType()`) and the Schur preconditioner type to `PC_FIELDSPLIT_SCHUR_PRE_SELF` (see `PCFieldSplitSetSchurPre()`). 3108 3109 .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDetectSaddlePoint()`, `PCFieldSplitSetType()`, `PCFieldSplitSetSchurPre()`, `PC_FIELDSPLIT_SCHUR_PRE_SELF` 3110 @*/ 3111 PetscErrorCode PCFieldSplitSetDetectSaddlePoint(PC pc, PetscBool flg) 3112 { 3113 PC_FieldSplit *jac = (PC_FieldSplit *)pc->data; 3114 3115 PetscFunctionBegin; 3116 jac->detect = flg; 3117 if (jac->detect) { 3118 PetscCall(PCFieldSplitSetType(pc, PC_COMPOSITE_SCHUR)); 3119 PetscCall(PCFieldSplitSetSchurPre(pc, PC_FIELDSPLIT_SCHUR_PRE_SELF, NULL)); 3120 } 3121 PetscFunctionReturn(PETSC_SUCCESS); 3122 } 3123 3124 /*MC 3125 PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual 3126 collections of variables (that may overlap) called splits. See [the users manual section on "Solving Block Matrices"](sec_block_matrices) for more details. 3127 3128 Options Database Keys: 3129 + -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the `%d`'th split 3130 . -pc_fieldsplit_default - automatically add any fields to additional splits that have not 3131 been supplied explicitly by `-pc_fieldsplit_%d_fields` 3132 . -pc_fieldsplit_block_size <bs> - size of block that defines fields (i.e. there are bs fields) 3133 . -pc_fieldsplit_type <additive,multiplicative,symmetric_multiplicative,schur,gkb> - type of relaxation or factorization splitting 3134 . -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is `a11`; see `PCFieldSplitSetSchurPre()` 3135 . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> - set factorization type when using `-pc_fieldsplit_type schur`; 3136 see `PCFieldSplitSetSchurFactType()` 3137 - -pc_fieldsplit_detect_saddle_point - automatically finds rows with zero diagonal and uses Schur complement with no preconditioner as the solver 3138 3139 Options prefixes for inner solvers when using the Schur complement preconditioner are `-fieldsplit_0_` and `-fieldsplit_1_` . 3140 The options prefix for the inner solver when using the Golub-Kahan biadiagonalization preconditioner is `-fieldsplit_0_` 3141 For all other solvers they are `-fieldsplit_%d_` for the `%d`'th field; use `-fieldsplit_` for all fields. 3142 3143 To set options on the solvers for each block append `-fieldsplit_` to all the `PC` 3144 options database keys. For example, `-fieldsplit_pc_type ilu` `-fieldsplit_pc_factor_levels 1` 3145 3146 To set the options on the solvers separate for each block call `PCFieldSplitGetSubKSP()` 3147 and set the options directly on the resulting `KSP` object 3148 3149 Level: intermediate 3150 3151 Notes: 3152 Use `PCFieldSplitSetFields()` to set splits defined by "strided" entries and `PCFieldSplitSetIS()` 3153 to define a split by an arbitrary collection of entries. 3154 3155 If no splits are set the default is used. The splits are defined by entries strided by bs, 3156 beginning at 0 then 1, etc to bs-1. The block size can be set with `PCFieldSplitSetBlockSize()`, 3157 if this is not called the block size defaults to the blocksize of the second matrix passed 3158 to `KSPSetOperators()`/`PCSetOperators()`. 3159 3160 For the Schur complement preconditioner if 3161 3162 ```{math} 3163 J = \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{10} & A_{11} \end{array}\right] 3164 ``` 3165 3166 the preconditioner using `full` factorization is logically 3167 ```{math} 3168 \left[\begin{array}{cc} I & -\text{ksp}(A_{00}) A_{01} \\ 0 & I \end{array}\right] \left[\begin{array}{cc} \text{inv}(A_{00}) & 0 \\ 0 & \text{ksp}(S) \end{array}\right] \left[\begin{array}{cc} I & 0 \\ -A_{10} \text{ksp}(A_{00}) & I \end{array}\right] 3169 ``` 3170 where the action of $\text{inv}(A_{00})$ is applied using the KSP solver with prefix `-fieldsplit_0_`. $S$ is the Schur complement 3171 ```{math} 3172 S = A_{11} - A_{10} \text{ksp}(A_{00}) A_{01} 3173 ``` 3174 which is usually dense and not stored explicitly. The action of $\text{ksp}(S)$ is computed using the KSP solver with prefix `-fieldsplit_splitname_` (where `splitname` was given 3175 in providing the SECOND split or 1 if not given). For `PCFieldSplitGetSubKSP()` when field number is 0, 3176 it returns the KSP associated with `-fieldsplit_0_` while field number 1 gives `-fieldsplit_1_` KSP. By default 3177 $A_{11}$ is used to construct a preconditioner for $S$, use `PCFieldSplitSetSchurPre()` for all the possible ways to construct the preconditioner for $S$. 3178 3179 The factorization type is set using `-pc_fieldsplit_schur_fact_type <diag, lower, upper, full>`. `full` is shown above, 3180 `diag` gives 3181 ```{math} 3182 \left[\begin{array}{cc} \text{inv}(A_{00}) & 0 \\ 0 & -\text{ksp}(S) \end{array}\right] 3183 ``` 3184 Note that, slightly counter intuitively, there is a negative in front of the $\text{ksp}(S)$ so that the preconditioner is positive definite. For SPD matrices $J$, the sign flip 3185 can be turned off with `PCFieldSplitSetSchurScale()` or by command line `-pc_fieldsplit_schur_scale 1.0`. The `lower` factorization is the inverse of 3186 ```{math} 3187 \left[\begin{array}{cc} A_{00} & 0 \\ A_{10} & S \end{array}\right] 3188 ``` 3189 where the inverses of A_{00} and S are applied using KSPs. The upper factorization is the inverse of 3190 ```{math} 3191 \left[\begin{array}{cc} A_{00} & A_{01} \\ 0 & S \end{array}\right] 3192 ``` 3193 where again the inverses of $A_{00}$ and $S$ are applied using `KSP`s. 3194 3195 If only one set of indices (one `IS`) is provided with `PCFieldSplitSetIS()` then the complement of that `IS` 3196 is used automatically for a second block. 3197 3198 The fieldsplit preconditioner cannot currently be used with the `MATBAIJ` or `MATSBAIJ` data formats if the blocksize is larger than 1. 3199 Generally it should be used with the `MATAIJ` format. 3200 3201 The forms of these preconditioners are closely related if not identical to forms derived as "Distributive Iterations", see, 3202 for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling {cite}`wesseling2009`. 3203 One can also use `PCFIELDSPLIT` 3204 inside a smoother resulting in "Distributive Smoothers". 3205 3206 See "A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations" {cite}`elman2008tcp`. 3207 3208 The Constrained Pressure Preconditioner (CPR) can be implemented using `PCCOMPOSITE` with `PCGALERKIN`. CPR first solves an $R A P$ subsystem, updates the 3209 residual on all variables (`PCCompositeSetType(pc,PC_COMPOSITE_MULTIPLICATIVE)`), and then applies a simple ILU like preconditioner on all the variables. 3210 3211 The generalized Golub-Kahan bidiagonalization preconditioner (GKB) can be applied to symmetric $2 \times 2$ block matrices of the shape 3212 ```{math} 3213 \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{01}' & 0 \end{array}\right] 3214 ``` 3215 with $A_{00}$ positive semi-definite. The implementation follows {cite}`arioli2013`. Therein, we choose $N := 1/\nu * I$ and the $(1,1)$-block of the matrix is modified to $H = _{A00} + \nu*A_{01}*A_{01}'$. 3216 A linear system $Hx = b$ has to be solved in each iteration of the GKB algorithm. This solver is chosen with the option prefix `-fieldsplit_0_`. 3217 3218 Developer Note: 3219 The Schur complement functionality of `PCFIELDSPLIT` should likely be factored into its own `PC` thus simplifying the implementation of the preconditioners and their 3220 user API. 3221 3222 .seealso: [](sec_block_matrices), `PC`, `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCLSC`, 3223 `PCFieldSplitGetSubKSP()`, `PCFieldSplitSchurGetSubKSP()`, `PCFieldSplitSetFields()`, 3224 `PCFieldSplitSetType()`, `PCFieldSplitSetIS()`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitSetSchurFactType()`, 3225 `MatSchurComplementSetAinvType()`, `PCFieldSplitSetSchurScale()`, `PCFieldSplitSetDetectSaddlePoint()` 3226 M*/ 3227 3228 PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc) 3229 { 3230 PC_FieldSplit *jac; 3231 3232 PetscFunctionBegin; 3233 PetscCall(PetscNew(&jac)); 3234 3235 jac->bs = -1; 3236 jac->nsplits = 0; 3237 jac->type = PC_COMPOSITE_MULTIPLICATIVE; 3238 jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */ 3239 jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL; 3240 jac->schurscale = -1.0; 3241 jac->dm_splits = PETSC_TRUE; 3242 jac->detect = PETSC_FALSE; 3243 jac->gkbtol = 1e-5; 3244 jac->gkbdelay = 5; 3245 jac->gkbnu = 1; 3246 jac->gkbmaxit = 100; 3247 jac->gkbmonitor = PETSC_FALSE; 3248 jac->coordinates_set = PETSC_FALSE; 3249 3250 pc->data = (void *)jac; 3251 3252 pc->ops->apply = PCApply_FieldSplit; 3253 pc->ops->applytranspose = PCApplyTranspose_FieldSplit; 3254 pc->ops->setup = PCSetUp_FieldSplit; 3255 pc->ops->reset = PCReset_FieldSplit; 3256 pc->ops->destroy = PCDestroy_FieldSplit; 3257 pc->ops->setfromoptions = PCSetFromOptions_FieldSplit; 3258 pc->ops->view = PCView_FieldSplit; 3259 pc->ops->applyrichardson = NULL; 3260 3261 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", PCFieldSplitSchurGetSubKSP_FieldSplit)); 3262 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit)); 3263 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", PCFieldSplitSetFields_FieldSplit)); 3264 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", PCFieldSplitSetIS_FieldSplit)); 3265 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", PCFieldSplitSetType_FieldSplit)); 3266 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", PCFieldSplitSetBlockSize_FieldSplit)); 3267 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", PCFieldSplitRestrictIS_FieldSplit)); 3268 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", PCSetCoordinates_FieldSplit)); 3269 PetscFunctionReturn(PETSC_SUCCESS); 3270 } 3271