Actual source code: fieldsplit.c
1: #include <petsc/private/pcimpl.h>
2: #include <petsc/private/kspimpl.h>
3: #include <petscdm.h>
4: #include <petscdevice.h>
5: #if PetscDefined(HAVE_CUDA)
6: #include <petscdevice_cuda.h>
7: #endif
8: #if PetscDefined(HAVE_HIP)
9: #include <petscdevice_hip.h>
10: #endif
12: const char *const PCFieldSplitSchurPreTypes[] = {"SELF", "SELFP", "A11", "USER", "FULL", "PCFieldSplitSchurPreType", "PC_FIELDSPLIT_SCHUR_PRE_", NULL};
13: const char *const PCFieldSplitSchurFactTypes[] = {"DIAG", "LOWER", "UPPER", "FULL", "PCFieldSplitSchurFactType", "PC_FIELDSPLIT_SCHUR_FACT_", NULL};
15: 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;
17: typedef struct _PC_FieldSplitLink *PC_FieldSplitLink;
18: struct _PC_FieldSplitLink {
19: KSP ksp;
20: Vec x, y, z;
21: char *splitname;
22: PetscInt nfields;
23: PetscInt *fields, *fields_col;
24: VecScatter sctx;
25: IS is, is_col;
26: PC_FieldSplitLink next, previous;
27: PetscLogEvent event;
29: /* Used only when setting coordinates with PCSetCoordinates */
30: PetscInt dim;
31: PetscInt ndofs;
32: PetscReal *coords;
33: };
35: typedef struct {
36: PCCompositeType type;
37: PetscBool defaultsplit; /* Flag for a system with a set of 'k' scalar fields with the same layout (and bs = k) */
38: PetscBool splitdefined; /* Flag is set after the splits have been defined, to prevent more splits from being added */
39: PetscInt bs; /* Block size for IS and Mat structures */
40: PetscInt nsplits; /* Number of field divisions defined */
41: Vec *x, *y, w1, w2;
42: Mat *mat; /* The diagonal block for each split */
43: Mat *pmat; /* The preconditioning diagonal block for each split */
44: Mat *Afield; /* The rows of the matrix associated with each split */
45: PetscBool issetup;
47: /* Only used when Schur complement preconditioning is used */
48: Mat B; /* The (0,1) block */
49: Mat C; /* The (1,0) block */
50: Mat schur; /* The Schur complement S = A11 - A10 A00^{-1} A01, the KSP here, kspinner, is H_1 in [El08] */
51: Mat schurp; /* Assembled approximation to S built by MatSchurComplement to be used as a matrix for constructing the preconditioner when solving with S */
52: Mat schur_user; /* User-provided matrix for constructing the preconditioner for the Schur complement */
53: PCFieldSplitSchurPreType schurpre; /* Determines which matrix is used for the Schur complement */
54: PCFieldSplitSchurFactType schurfactorization;
55: KSP kspschur; /* The solver for S */
56: KSP kspupper; /* The solver for A in the upper diagonal part of the factorization (H_2 in [El08]) */
57: PetscScalar schurscale; /* Scaling factor for the Schur complement solution with DIAG factorization */
59: /* Only used when Golub-Kahan bidiagonalization preconditioning is used */
60: Mat H; /* The modified matrix H = A00 + nu*A01*A01' */
61: PetscReal gkbtol; /* Stopping tolerance for lower bound estimate */
62: PetscInt gkbdelay; /* The delay window for the stopping criterion */
63: PetscReal gkbnu; /* Parameter for augmented Lagrangian H = A + nu*A01*A01' */
64: PetscInt gkbmaxit; /* Maximum number of iterations for outer loop */
65: PetscBool gkbmonitor; /* Monitor for gkb iterations and the lower bound error */
66: PetscViewer gkbviewer; /* Viewer context for gkbmonitor */
67: Vec u, v, d, Hu; /* Work vectors for the GKB algorithm */
68: PetscScalar *vecz; /* Contains intermediate values, eg for lower bound */
70: PC_FieldSplitLink head;
71: PetscBool isrestrict; /* indicates PCFieldSplitRestrictIS() has been last called on this object, hack */
72: PetscBool suboptionsset; /* Indicates that the KSPSetFromOptions() has been called on the sub-KSPs */
73: PetscBool dm_splits; /* Whether to use DMCreateFieldDecomposition() whenever possible */
74: PetscBool diag_use_amat; /* Whether to extract diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */
75: PetscBool offdiag_use_amat; /* Whether to extract off-diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */
76: PetscBool detect; /* Whether to form 2-way split by finding zero diagonal entries */
77: PetscBool coordinates_set; /* Whether PCSetCoordinates has been called */
78: } PC_FieldSplit;
80: /*
81: Note:
82: there is no particular reason that pmat, x, and y are stored as arrays in PC_FieldSplit instead of
83: inside PC_FieldSplitLink, just historical. If you want to be able to add new fields after already using the
84: PC you could change this.
85: */
87: /* This helper is so that setting a user-provided matrix is orthogonal to choosing to use it. This way the
88: * application-provided FormJacobian can provide this matrix without interfering with the user's (command-line) choices. */
89: static Mat FieldSplitSchurPre(PC_FieldSplit *jac)
90: {
91: switch (jac->schurpre) {
92: case PC_FIELDSPLIT_SCHUR_PRE_SELF:
93: return jac->schur;
94: case PC_FIELDSPLIT_SCHUR_PRE_SELFP:
95: return jac->schurp;
96: case PC_FIELDSPLIT_SCHUR_PRE_A11:
97: return jac->pmat[1];
98: case PC_FIELDSPLIT_SCHUR_PRE_FULL: /* We calculate this and store it in schur_user */
99: case PC_FIELDSPLIT_SCHUR_PRE_USER: /* Use a user-provided matrix if it is given, otherwise diagonal block */
100: default:
101: return jac->schur_user ? jac->schur_user : jac->pmat[1];
102: }
103: }
105: #include <petscdraw.h>
106: static PetscErrorCode PCView_FieldSplit(PC pc, PetscViewer viewer)
107: {
108: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
109: PetscBool isascii, isdraw;
110: PetscInt i, j;
111: PC_FieldSplitLink ilink = jac->head;
113: PetscFunctionBegin;
114: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
115: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
116: if (isascii) {
117: if (jac->bs > 0) {
118: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT ", blocksize = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits, jac->bs));
119: } else {
120: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits));
121: }
122: if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n"));
123: if (jac->diag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for diagonal blocks\n"));
124: if (jac->offdiag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for off-diagonal blocks\n"));
125: PetscCall(PetscViewerASCIIPrintf(viewer, " Solver info for each split is in the following KSP objects:\n"));
126: for (i = 0; i < jac->nsplits; i++) {
127: if (ilink->fields) {
128: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Fields ", i));
129: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
130: for (j = 0; j < ilink->nfields; j++) {
131: if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ","));
132: PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j]));
133: }
134: PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
135: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
136: } else {
137: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Defined by IS\n", i));
138: }
139: PetscCall(KSPView(ilink->ksp, viewer));
140: ilink = ilink->next;
141: }
142: }
144: if (isdraw) {
145: PetscDraw draw;
146: PetscReal x, y, w, wd;
148: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
149: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
150: w = 2 * PetscMin(1.0 - x, x);
151: wd = w / (jac->nsplits + 1);
152: x = x - wd * (jac->nsplits - 1) / 2.0;
153: for (i = 0; i < jac->nsplits; i++) {
154: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
155: PetscCall(KSPView(ilink->ksp, viewer));
156: PetscCall(PetscDrawPopCurrentPoint(draw));
157: x += wd;
158: ilink = ilink->next;
159: }
160: }
161: PetscFunctionReturn(PETSC_SUCCESS);
162: }
164: static PetscErrorCode PCView_FieldSplit_Schur(PC pc, PetscViewer viewer)
165: {
166: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
167: PetscBool isascii, isdraw;
168: PetscInt i, j;
169: PC_FieldSplitLink ilink = jac->head;
170: MatSchurComplementAinvType atype;
172: PetscFunctionBegin;
173: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
174: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
175: if (isascii) {
176: if (jac->bs > 0) {
177: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with Schur preconditioner, blocksize = %" PetscInt_FMT ", factorization %s\n", jac->bs, PCFieldSplitSchurFactTypes[jac->schurfactorization]));
178: } else {
179: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with Schur preconditioner, factorization %s\n", PCFieldSplitSchurFactTypes[jac->schurfactorization]));
180: }
181: if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n"));
182: switch (jac->schurpre) {
183: case PC_FIELDSPLIT_SCHUR_PRE_SELF:
184: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from S itself\n"));
185: break;
186: case PC_FIELDSPLIT_SCHUR_PRE_SELFP:
187: if (jac->schur) {
188: PetscCall(MatSchurComplementGetAinvType(jac->schur, &atype));
189: 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 "))));
190: }
191: break;
192: case PC_FIELDSPLIT_SCHUR_PRE_A11:
193: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from A11\n"));
194: break;
195: case PC_FIELDSPLIT_SCHUR_PRE_FULL:
196: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from the exact Schur complement\n"));
197: break;
198: case PC_FIELDSPLIT_SCHUR_PRE_USER:
199: if (jac->schur_user) {
200: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from user provided matrix\n"));
201: } else {
202: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from A11\n"));
203: }
204: break;
205: default:
206: SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Invalid Schur preconditioning type: %d", jac->schurpre);
207: }
208: PetscCall(PetscViewerASCIIPrintf(viewer, " Split info:\n"));
209: PetscCall(PetscViewerASCIIPushTab(viewer));
210: for (i = 0; i < jac->nsplits; i++) {
211: if (ilink->fields) {
212: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Fields ", i));
213: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
214: for (j = 0; j < ilink->nfields; j++) {
215: if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ","));
216: PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j]));
217: }
218: PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
219: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
220: } else {
221: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Defined by IS\n", i));
222: }
223: ilink = ilink->next;
224: }
225: PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for A00 block\n"));
226: PetscCall(PetscViewerASCIIPushTab(viewer));
227: if (jac->head) PetscCall(KSPView(jac->head->ksp, viewer));
228: else PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n"));
229: PetscCall(PetscViewerASCIIPopTab(viewer));
230: if (jac->head && jac->kspupper != jac->head->ksp) {
231: PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for upper A00 in upper triangular factor\n"));
232: PetscCall(PetscViewerASCIIPushTab(viewer));
233: if (jac->kspupper) PetscCall(KSPView(jac->kspupper, viewer));
234: else PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n"));
235: PetscCall(PetscViewerASCIIPopTab(viewer));
236: }
237: PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for S = A11 - A10 inv(A00) A01\n"));
238: PetscCall(PetscViewerASCIIPushTab(viewer));
239: if (jac->kspschur) {
240: PetscCall(KSPView(jac->kspschur, viewer));
241: } else {
242: PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n"));
243: }
244: PetscCall(PetscViewerASCIIPopTab(viewer));
245: PetscCall(PetscViewerASCIIPopTab(viewer));
246: } else if (isdraw && jac->head) {
247: PetscDraw draw;
248: PetscReal x, y, w, wd, h;
249: PetscInt cnt = 2;
250: char str[32];
252: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
253: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
254: if (jac->kspupper != jac->head->ksp) cnt++;
255: w = 2 * PetscMin(1.0 - x, x);
256: wd = w / (cnt + 1);
258: PetscCall(PetscSNPrintf(str, 32, "Schur fact. %s", PCFieldSplitSchurFactTypes[jac->schurfactorization]));
259: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_RED, PETSC_DRAW_BLACK, str, NULL, &h));
260: y -= h;
261: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_USER && !jac->schur_user) {
262: PetscCall(PetscSNPrintf(str, 32, "Prec. for Schur from %s", PCFieldSplitSchurPreTypes[PC_FIELDSPLIT_SCHUR_PRE_A11]));
263: } else {
264: PetscCall(PetscSNPrintf(str, 32, "Prec. for Schur from %s", PCFieldSplitSchurPreTypes[jac->schurpre]));
265: }
266: PetscCall(PetscDrawStringBoxed(draw, x + wd * (cnt - 1) / 2.0, y, PETSC_DRAW_RED, PETSC_DRAW_BLACK, str, NULL, &h));
267: y -= h;
268: x = x - wd * (cnt - 1) / 2.0;
270: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
271: PetscCall(KSPView(jac->head->ksp, viewer));
272: PetscCall(PetscDrawPopCurrentPoint(draw));
273: if (jac->kspupper != jac->head->ksp) {
274: x += wd;
275: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
276: PetscCall(KSPView(jac->kspupper, viewer));
277: PetscCall(PetscDrawPopCurrentPoint(draw));
278: }
279: x += wd;
280: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
281: PetscCall(KSPView(jac->kspschur, viewer));
282: PetscCall(PetscDrawPopCurrentPoint(draw));
283: }
284: PetscFunctionReturn(PETSC_SUCCESS);
285: }
287: static PetscErrorCode PCView_FieldSplit_GKB(PC pc, PetscViewer viewer)
288: {
289: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
290: PetscBool isascii, isdraw;
291: PetscInt i, j;
292: PC_FieldSplitLink ilink = jac->head;
294: PetscFunctionBegin;
295: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
296: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
297: if (isascii) {
298: if (jac->bs > 0) {
299: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT ", blocksize = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits, jac->bs));
300: } else {
301: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits));
302: }
303: if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n"));
304: if (jac->diag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for diagonal blocks\n"));
305: if (jac->offdiag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for off-diagonal blocks\n"));
307: PetscCall(PetscViewerASCIIPrintf(viewer, " Stopping tolerance=%.1e, delay in error estimate=%" PetscInt_FMT ", maximum iterations=%" PetscInt_FMT "\n", (double)jac->gkbtol, jac->gkbdelay, jac->gkbmaxit));
308: PetscCall(PetscViewerASCIIPrintf(viewer, " Solver info for H = A00 + nu*A01*A01' matrix:\n"));
309: PetscCall(PetscViewerASCIIPushTab(viewer));
311: if (ilink->fields) {
312: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number 0 Fields "));
313: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
314: for (j = 0; j < ilink->nfields; j++) {
315: if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ","));
316: PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j]));
317: }
318: PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
319: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
320: } else {
321: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number 0 Defined by IS\n"));
322: }
323: PetscCall(KSPView(ilink->ksp, viewer));
325: PetscCall(PetscViewerASCIIPopTab(viewer));
326: }
328: if (isdraw) {
329: PetscDraw draw;
330: PetscReal x, y, w, wd;
332: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
333: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
334: w = 2 * PetscMin(1.0 - x, x);
335: wd = w / (jac->nsplits + 1);
336: x = x - wd * (jac->nsplits - 1) / 2.0;
337: for (i = 0; i < jac->nsplits; i++) {
338: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
339: PetscCall(KSPView(ilink->ksp, viewer));
340: PetscCall(PetscDrawPopCurrentPoint(draw));
341: x += wd;
342: ilink = ilink->next;
343: }
344: }
345: PetscFunctionReturn(PETSC_SUCCESS);
346: }
348: /* Precondition: jac->bs is set to a meaningful value or MATNEST */
349: static PetscErrorCode PCFieldSplitSetRuntimeSplits_Private(PC pc)
350: {
351: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
352: PetscInt bs, i, nfields, *ifields, nfields_col, *ifields_col;
353: PetscBool flg, flg_col, mnest;
354: char optionname[128], splitname[8], optionname_col[128];
356: PetscFunctionBegin;
357: PetscCall(PetscObjectTypeCompare((PetscObject)pc->mat, MATNEST, &mnest));
358: if (mnest) {
359: PetscCall(MatNestGetSize(pc->pmat, &bs, NULL));
360: } else {
361: bs = jac->bs;
362: }
363: PetscCall(PetscMalloc2(bs, &ifields, bs, &ifields_col));
364: for (i = 0, flg = PETSC_TRUE;; i++) {
365: PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i));
366: PetscCall(PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%" PetscInt_FMT "_fields", i));
367: PetscCall(PetscSNPrintf(optionname_col, sizeof(optionname_col), "-pc_fieldsplit_%" PetscInt_FMT "_fields_col", i));
368: nfields = bs;
369: nfields_col = bs;
370: PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname, ifields, &nfields, &flg));
371: PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname_col, ifields_col, &nfields_col, &flg_col));
372: if (!flg) break;
373: else if (flg && !flg_col) {
374: PetscCheck(nfields, PETSC_COMM_SELF, PETSC_ERR_USER, "Cannot list zero fields");
375: PetscCall(PCFieldSplitSetFields(pc, splitname, nfields, ifields, ifields));
376: } else {
377: PetscCheck(nfields && nfields_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Cannot list zero fields");
378: PetscCheck(nfields == nfields_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Number of row and column fields must match");
379: PetscCall(PCFieldSplitSetFields(pc, splitname, nfields, ifields, ifields_col));
380: }
381: }
382: if (i > 0) {
383: /* Makes command-line setting of splits take precedence over setting them in code.
384: Otherwise subsequent calls to PCFieldSplitSetIS() or PCFieldSplitSetFields() would
385: create new splits, which would probably not be what the user wanted. */
386: jac->splitdefined = PETSC_TRUE;
387: }
388: PetscCall(PetscFree2(ifields, ifields_col));
389: PetscFunctionReturn(PETSC_SUCCESS);
390: }
392: static PetscErrorCode PCFieldSplitSetDefaults(PC pc)
393: {
394: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
395: PC_FieldSplitLink ilink = jac->head;
396: PetscBool fieldsplit_default = PETSC_FALSE, coupling = PETSC_FALSE;
397: PetscInt i;
399: PetscFunctionBegin;
400: /*
401: Kinda messy, but at least this now uses DMCreateFieldDecomposition().
402: Should probably be rewritten.
403: */
404: if (!ilink) {
405: PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_detect_coupling", &coupling, NULL));
406: if (pc->dm && jac->dm_splits && !jac->detect && !coupling) {
407: PetscInt numFields, f, i, j;
408: char **fieldNames;
409: IS *fields;
410: DM *dms;
411: DM subdm[128];
412: PetscBool flg;
414: PetscCall(DMCreateFieldDecomposition(pc->dm, &numFields, &fieldNames, &fields, &dms));
415: /* Allow the user to prescribe the splits */
416: for (i = 0, flg = PETSC_TRUE;; i++) {
417: PetscInt ifields[128];
418: IS compField;
419: char optionname[128], splitname[8];
420: PetscInt nfields = numFields;
422: PetscCall(PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%" PetscInt_FMT "_fields", i));
423: PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname, ifields, &nfields, &flg));
424: if (!flg) break;
425: PetscCheck(numFields <= 128, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Cannot currently support %" PetscInt_FMT " > 128 fields", numFields);
426: PetscCall(DMCreateSubDM(pc->dm, nfields, ifields, &compField, &subdm[i]));
427: if (nfields == 1) {
428: PetscCall(PCFieldSplitSetIS(pc, fieldNames[ifields[0]], compField));
429: } else {
430: PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i));
431: PetscCall(PCFieldSplitSetIS(pc, splitname, compField));
432: }
433: PetscCall(ISDestroy(&compField));
434: for (j = 0; j < nfields; ++j) {
435: f = ifields[j];
436: PetscCall(PetscFree(fieldNames[f]));
437: PetscCall(ISDestroy(&fields[f]));
438: }
439: }
440: if (i == 0) {
441: for (f = 0; f < numFields; ++f) {
442: PetscCall(PCFieldSplitSetIS(pc, fieldNames[f], fields[f]));
443: PetscCall(PetscFree(fieldNames[f]));
444: PetscCall(ISDestroy(&fields[f]));
445: }
446: } else {
447: for (j = 0; j < numFields; j++) PetscCall(DMDestroy(dms + j));
448: PetscCall(PetscFree(dms));
449: PetscCall(PetscMalloc1(i, &dms));
450: for (j = 0; j < i; ++j) dms[j] = subdm[j];
451: }
452: PetscCall(PetscFree(fieldNames));
453: PetscCall(PetscFree(fields));
454: if (dms) {
455: PetscCall(PetscInfo(pc, "Setting up physics based fieldsplit preconditioner using the embedded DM\n"));
456: for (ilink = jac->head, i = 0; ilink; ilink = ilink->next, ++i) {
457: const char *prefix;
458: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)ilink->ksp, &prefix));
459: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)dms[i], prefix));
460: PetscCall(KSPSetDM(ilink->ksp, dms[i]));
461: PetscCall(KSPSetDMActive(ilink->ksp, PETSC_FALSE));
462: PetscCall(PetscObjectIncrementTabLevel((PetscObject)dms[i], (PetscObject)ilink->ksp, 0));
463: PetscCall(DMDestroy(&dms[i]));
464: }
465: PetscCall(PetscFree(dms));
466: }
467: } else {
468: if (jac->bs <= 0) {
469: if (pc->pmat) PetscCall(MatGetBlockSize(pc->pmat, &jac->bs));
470: else jac->bs = 1;
471: }
473: if (jac->detect) {
474: IS zerodiags, rest;
475: PetscInt nmin, nmax;
477: PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax));
478: if (jac->diag_use_amat) {
479: PetscCall(MatFindZeroDiagonals(pc->mat, &zerodiags));
480: } else {
481: PetscCall(MatFindZeroDiagonals(pc->pmat, &zerodiags));
482: }
483: PetscCall(ISComplement(zerodiags, nmin, nmax, &rest));
484: PetscCall(PCFieldSplitSetIS(pc, "0", rest));
485: PetscCall(PCFieldSplitSetIS(pc, "1", zerodiags));
486: PetscCall(ISDestroy(&zerodiags));
487: PetscCall(ISDestroy(&rest));
488: } else if (coupling) {
489: IS coupling, rest;
490: PetscInt nmin, nmax;
492: PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax));
493: if (jac->offdiag_use_amat) {
494: PetscCall(MatFindOffBlockDiagonalEntries(pc->mat, &coupling));
495: } else {
496: PetscCall(MatFindOffBlockDiagonalEntries(pc->pmat, &coupling));
497: }
498: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc->mat), nmax - nmin, nmin, 1, &rest));
499: PetscCall(ISSetIdentity(rest));
500: PetscCall(PCFieldSplitSetIS(pc, "0", rest));
501: PetscCall(PCFieldSplitSetIS(pc, "1", coupling));
502: PetscCall(ISDestroy(&coupling));
503: PetscCall(ISDestroy(&rest));
504: } else {
505: PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_default", &fieldsplit_default, NULL));
506: if (!fieldsplit_default) {
507: /* Allow user to set fields from command line, if bs was known at the time of PCSetFromOptions_FieldSplit()
508: then it is set there. This is not ideal because we should only have options set in XXSetFromOptions(). */
509: PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc));
510: if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n"));
511: }
512: if ((fieldsplit_default || !jac->splitdefined) && !jac->isrestrict) {
513: Mat M = pc->pmat;
514: PetscBool isnest;
515: PetscInt nf;
517: PetscCall(PetscInfo(pc, "Using default splitting of fields\n"));
518: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &isnest));
519: if (!isnest) {
520: M = pc->mat;
521: PetscCall(PetscObjectTypeCompare((PetscObject)pc->mat, MATNEST, &isnest));
522: }
523: if (!isnest) nf = jac->bs;
524: else PetscCall(MatNestGetSize(M, &nf, NULL));
525: for (i = 0; i < nf; i++) {
526: char splitname[8];
528: PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i));
529: PetscCall(PCFieldSplitSetFields(pc, splitname, 1, &i, &i));
530: }
531: jac->defaultsplit = PETSC_TRUE;
532: }
533: }
534: }
535: } else if (jac->nsplits == 1) {
536: IS is2;
537: PetscInt nmin, nmax;
539: PetscCheck(ilink->is, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Must provide at least two sets of fields to PCFieldSplit()");
540: PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax));
541: PetscCall(ISComplement(ilink->is, nmin, nmax, &is2));
542: PetscCall(PCFieldSplitSetIS(pc, "1", is2));
543: PetscCall(ISDestroy(&is2));
544: }
546: PetscCheck(jac->nsplits >= 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unhandled case, must have at least two fields, not %" PetscInt_FMT, jac->nsplits);
547: PetscFunctionReturn(PETSC_SUCCESS);
548: }
550: static PetscErrorCode MatGolubKahanComputeExplicitOperator(Mat A, Mat B, Mat C, Mat *H, PetscReal gkbnu)
551: {
552: Mat BT, T;
553: PetscReal nrmT, nrmB;
555: PetscFunctionBegin;
556: PetscCall(MatHermitianTranspose(C, MAT_INITIAL_MATRIX, &T)); /* Test if augmented matrix is symmetric */
557: PetscCall(MatAXPY(T, -1.0, B, DIFFERENT_NONZERO_PATTERN));
558: PetscCall(MatNorm(T, NORM_1, &nrmT));
559: PetscCall(MatNorm(B, NORM_1, &nrmB));
560: PetscCheck(nrmB <= 0 || nrmT / nrmB < PETSC_SMALL, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Matrix is not symmetric/hermitian, GKB is not applicable.");
562: /* Compute augmented Lagrangian matrix H = A00 + nu*A01*A01'. This corresponds to */
563: /* setting N := 1/nu*I in [Ar13]. */
564: PetscCall(MatHermitianTranspose(B, MAT_INITIAL_MATRIX, &BT));
565: PetscCall(MatMatMult(B, BT, MAT_INITIAL_MATRIX, PETSC_CURRENT, H)); /* H = A01*A01' */
566: PetscCall(MatAYPX(*H, gkbnu, A, DIFFERENT_NONZERO_PATTERN)); /* H = A00 + nu*A01*A01' */
568: PetscCall(MatDestroy(&BT));
569: PetscCall(MatDestroy(&T));
570: PetscFunctionReturn(PETSC_SUCCESS);
571: }
573: PETSC_EXTERN PetscErrorCode PetscOptionsFindPairPrefix_Private(PetscOptions, const char pre[], const char name[], const char *option[], const char *value[], PetscBool *flg);
575: static PetscErrorCode PCSetUp_FieldSplit(PC pc)
576: {
577: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
578: PC_FieldSplitLink ilink;
579: PetscInt i, nsplit;
580: PetscBool matnest = PETSC_FALSE;
582: PetscFunctionBegin;
583: pc->failedreason = PC_NOERROR;
584: PetscCall(PCFieldSplitSetDefaults(pc));
585: nsplit = jac->nsplits;
586: ilink = jac->head;
587: if (pc->pmat) PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
589: /* get the matrices for each split */
590: if (!jac->issetup) {
591: PetscInt rstart, rend, nslots, bs;
593: jac->issetup = PETSC_TRUE;
595: /* This is done here instead of in PCFieldSplitSetFields() because may not have matrix at that point */
596: if (jac->defaultsplit || !ilink->is) {
597: if (jac->bs <= 0) jac->bs = nsplit;
598: }
600: /* MatCreateSubMatrix() for [S]BAIJ matrices can only work if the indices include entire blocks of the matrix */
601: PetscCall(MatGetBlockSize(pc->pmat, &bs));
602: if (bs > 1 && (jac->bs <= bs || jac->bs % bs)) {
603: PetscBool blk;
605: PetscCall(PetscObjectTypeCompareAny((PetscObject)pc->pmat, &blk, MATBAIJ, MATSBAIJ, MATSEQBAIJ, MATSEQSBAIJ, MATMPIBAIJ, MATMPISBAIJ, NULL));
606: PetscCheck(!blk, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Cannot use MATBAIJ with PCFIELDSPLIT and currently set matrix and PC blocksizes");
607: }
609: if (!matnest) { /* use the matrix blocksize and stride IS to determine the index sets that define the submatrices */
610: bs = jac->bs;
611: PetscCall(MatGetOwnershipRange(pc->pmat, &rstart, &rend));
612: nslots = (rend - rstart) / bs;
613: for (i = 0; i < nsplit; i++) {
614: if (jac->defaultsplit) {
615: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + i, nsplit, &ilink->is));
616: PetscCall(PetscObjectReference((PetscObject)ilink->is));
617: ilink->is_col = ilink->is;
618: } else if (!ilink->is) {
619: PetscBool same_fields = PETSC_TRUE;
621: for (PetscInt k = 0; k < ilink->nfields; k++) {
622: if (ilink->fields[k] != ilink->fields_col[k]) same_fields = PETSC_FALSE;
623: }
625: if (ilink->nfields > 1) {
626: PetscInt *ii, *jj, j, k, nfields = ilink->nfields, *fields = ilink->fields, *fields_col = ilink->fields_col;
628: PetscCall(PetscMalloc1(ilink->nfields * nslots, &ii));
629: if (!same_fields) PetscCall(PetscMalloc1(ilink->nfields * nslots, &jj));
630: for (j = 0; j < nslots; j++) {
631: for (k = 0; k < nfields; k++) {
632: ii[nfields * j + k] = rstart + bs * j + fields[k];
633: if (!same_fields) jj[nfields * j + k] = rstart + bs * j + fields_col[k];
634: }
635: }
636: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, ii, PETSC_OWN_POINTER, &ilink->is));
637: if (!same_fields) PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, jj, PETSC_OWN_POINTER, &ilink->is_col));
638: else {
639: PetscCall(PetscObjectReference((PetscObject)ilink->is));
640: ilink->is_col = ilink->is;
641: }
642: PetscCall(ISSetBlockSize(ilink->is, nfields));
643: PetscCall(ISSetBlockSize(ilink->is_col, nfields));
644: } else {
645: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields[0], bs, &ilink->is));
646: if (!same_fields) PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields_col[0], bs, &ilink->is_col));
647: else {
648: PetscCall(PetscObjectReference((PetscObject)ilink->is));
649: ilink->is_col = ilink->is;
650: }
651: }
652: }
653: ilink = ilink->next;
654: }
655: } else { /* use the IS that define the MATNEST to determine the index sets that define the submatrices */
656: IS *rowis, *colis, *ises = NULL;
657: PetscInt mis, nis;
659: PetscCall(MatNestGetSize(pc->pmat, &mis, &nis));
660: PetscCall(PetscMalloc2(mis, &rowis, nis, &colis));
661: PetscCall(MatNestGetISs(pc->pmat, rowis, colis));
662: if (!jac->defaultsplit) PetscCall(PetscMalloc1(mis, &ises));
664: for (i = 0; i < nsplit; i++) {
665: if (jac->defaultsplit) {
666: PetscCall(ISDuplicate(rowis[i], &ilink->is));
667: PetscCall(PetscObjectReference((PetscObject)ilink->is));
668: ilink->is_col = ilink->is;
669: } else if (!ilink->is) {
670: if (ilink->nfields > 1) {
671: for (PetscInt j = 0; j < ilink->nfields; j++) ises[j] = rowis[ilink->fields[j]];
672: PetscCall(ISConcatenate(PetscObjectComm((PetscObject)pc), ilink->nfields, ises, &ilink->is));
673: } else {
674: PetscCall(ISDuplicate(rowis[ilink->fields[0]], &ilink->is));
675: }
676: PetscCall(PetscObjectReference((PetscObject)ilink->is));
677: ilink->is_col = ilink->is;
678: }
679: ilink = ilink->next;
680: }
681: PetscCall(PetscFree2(rowis, colis));
682: PetscCall(PetscFree(ises));
683: }
684: }
686: ilink = jac->head;
687: if (!jac->pmat) {
688: Vec xtmp;
690: PetscCall(MatCreateVecs(pc->pmat, &xtmp, NULL));
691: PetscCall(PetscMalloc1(nsplit, &jac->pmat));
692: PetscCall(PetscMalloc2(nsplit, &jac->x, nsplit, &jac->y));
693: for (i = 0; i < nsplit; i++) {
694: MatNullSpace sp;
696: /* Check for matrix attached to IS */
697: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&jac->pmat[i]));
698: if (jac->pmat[i]) {
699: PetscCall(PetscObjectReference((PetscObject)jac->pmat[i]));
700: if (jac->type == PC_COMPOSITE_SCHUR) {
701: jac->schur_user = jac->pmat[i];
703: PetscCall(PetscObjectReference((PetscObject)jac->schur_user));
704: }
705: } else {
706: const char *prefix;
707: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->pmat[i]));
708: PetscCall(MatGetOptionsPrefix(jac->pmat[i], &prefix));
709: if (!prefix) {
710: PetscCall(KSPGetOptionsPrefix(ilink->ksp, &prefix));
711: PetscCall(MatSetOptionsPrefix(jac->pmat[i], prefix));
712: }
713: PetscCall(MatSetFromOptions(jac->pmat[i]));
714: PetscCall(MatViewFromOptions(jac->pmat[i], NULL, "-mat_view"));
715: }
716: /* create work vectors for each split */
717: PetscCall(MatCreateVecs(jac->pmat[i], &jac->x[i], &jac->y[i]));
718: ilink->x = jac->x[i];
719: ilink->y = jac->y[i];
720: ilink->z = NULL;
721: /* compute scatter contexts needed by multiplicative versions and non-default splits */
722: PetscCall(VecScatterCreate(xtmp, ilink->is, jac->x[i], NULL, &ilink->sctx));
723: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nearnullspace", (PetscObject *)&sp));
724: if (sp) PetscCall(MatSetNearNullSpace(jac->pmat[i], sp));
725: ilink = ilink->next;
726: }
727: PetscCall(VecDestroy(&xtmp));
728: } else {
729: MatReuse scall;
730: MatNullSpace *nullsp = NULL;
732: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
733: PetscCall(MatGetNullSpaces(nsplit, jac->pmat, &nullsp));
734: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->pmat[i]));
735: scall = MAT_INITIAL_MATRIX;
736: } else scall = MAT_REUSE_MATRIX;
738: for (i = 0; i < nsplit; i++) {
739: Mat pmat;
741: /* Check for matrix attached to IS */
742: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&pmat));
743: if (!pmat) PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, scall, &jac->pmat[i]));
744: ilink = ilink->next;
745: }
746: if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->pmat, &nullsp));
747: }
748: if (jac->diag_use_amat) {
749: ilink = jac->head;
750: if (!jac->mat) {
751: PetscCall(PetscMalloc1(nsplit, &jac->mat));
752: for (i = 0; i < nsplit; i++) {
753: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->mat[i]));
754: ilink = ilink->next;
755: }
756: } else {
757: MatReuse scall;
758: MatNullSpace *nullsp = NULL;
760: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
761: PetscCall(MatGetNullSpaces(nsplit, jac->mat, &nullsp));
762: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->mat[i]));
763: scall = MAT_INITIAL_MATRIX;
764: } else scall = MAT_REUSE_MATRIX;
766: for (i = 0; i < nsplit; i++) {
767: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, scall, &jac->mat[i]));
768: ilink = ilink->next;
769: }
770: if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->mat, &nullsp));
771: }
772: } else {
773: jac->mat = jac->pmat;
774: }
776: /* Check for null space attached to IS */
777: ilink = jac->head;
778: for (i = 0; i < nsplit; i++) {
779: MatNullSpace sp;
781: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nullspace", (PetscObject *)&sp));
782: if (sp) PetscCall(MatSetNullSpace(jac->mat[i], sp));
783: ilink = ilink->next;
784: }
786: if (jac->type != PC_COMPOSITE_ADDITIVE && jac->type != PC_COMPOSITE_SCHUR && jac->type != PC_COMPOSITE_GKB) {
787: /* extract the rows of the matrix associated with each field: used for efficient computation of residual inside algorithm */
788: /* FIXME: Can/should we reuse jac->mat whenever (jac->diag_use_amat) is true? */
789: ilink = jac->head;
790: if (nsplit == 2 && jac->type == PC_COMPOSITE_MULTIPLICATIVE) {
791: /* 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 */
792: if (!jac->Afield) {
793: PetscCall(PetscCalloc1(nsplit, &jac->Afield));
794: if (jac->offdiag_use_amat) {
795: PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1]));
796: } else {
797: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1]));
798: }
799: } else {
800: MatReuse scall;
802: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
803: PetscCall(MatDestroy(&jac->Afield[1]));
804: scall = MAT_INITIAL_MATRIX;
805: } else scall = MAT_REUSE_MATRIX;
807: if (jac->offdiag_use_amat) {
808: PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, scall, &jac->Afield[1]));
809: } else {
810: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, scall, &jac->Afield[1]));
811: }
812: }
813: } else {
814: if (!jac->Afield) {
815: PetscCall(PetscMalloc1(nsplit, &jac->Afield));
816: for (i = 0; i < nsplit; i++) {
817: if (jac->offdiag_use_amat) {
818: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i]));
819: } else {
820: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i]));
821: }
822: ilink = ilink->next;
823: }
824: } else {
825: MatReuse scall;
826: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
827: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->Afield[i]));
828: scall = MAT_INITIAL_MATRIX;
829: } else scall = MAT_REUSE_MATRIX;
831: for (i = 0; i < nsplit; i++) {
832: if (jac->offdiag_use_amat) {
833: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, scall, &jac->Afield[i]));
834: } else {
835: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, scall, &jac->Afield[i]));
836: }
837: ilink = ilink->next;
838: }
839: }
840: }
841: }
843: if (jac->type == PC_COMPOSITE_SCHUR) {
844: IS ccis;
845: PetscBool isset, isspd = PETSC_FALSE, issym = PETSC_FALSE, flg;
846: PetscInt rstart, rend;
847: char lscname[256];
848: PetscObject LSC_L;
850: PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use Schur complement preconditioner you must have exactly 2 fields");
852: /* If pc->mat is SPD, don't scale by -1 the Schur complement */
853: PetscCall(MatIsSPDKnown(pc->pmat, &isset, &isspd));
854: if (jac->schurscale == (PetscScalar)-1.0) jac->schurscale = (isset && isspd) ? 1.0 : -1.0;
855: PetscCall(MatIsSymmetricKnown(pc->pmat, &isset, &issym));
857: /* When extracting off-diagonal submatrices, we take complements from this range */
858: PetscCall(MatGetOwnershipRangeColumn(pc->mat, &rstart, &rend));
859: PetscCall(PetscObjectTypeCompareAny(jac->offdiag_use_amat ? (PetscObject)pc->mat : (PetscObject)pc->pmat, &flg, MATSEQSBAIJ, MATMPISBAIJ, ""));
861: if (jac->schur) {
862: KSP kspA = jac->head->ksp, kspInner = NULL, kspUpper = jac->kspupper;
863: MatReuse scall;
865: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
866: scall = MAT_INITIAL_MATRIX;
867: PetscCall(MatDestroy(&jac->B));
868: PetscCall(MatDestroy(&jac->C));
869: } else scall = MAT_REUSE_MATRIX;
871: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
872: ilink = jac->head;
873: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
874: if (jac->offdiag_use_amat) {
875: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, scall, &jac->B));
876: } else {
877: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, scall, &jac->B));
878: }
879: PetscCall(ISDestroy(&ccis));
880: if (!flg) {
881: ilink = ilink->next;
882: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
883: if (jac->offdiag_use_amat) {
884: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, scall, &jac->C));
885: } else {
886: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, scall, &jac->C));
887: }
888: PetscCall(ISDestroy(&ccis));
889: } else {
890: PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &isset, &flg));
891: if (isset && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C));
892: else PetscCall(MatCreateTranspose(jac->B, &jac->C));
893: }
894: PetscCall(MatSchurComplementUpdateSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1]));
895: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) {
896: PetscCall(MatDestroy(&jac->schurp));
897: PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp));
898: } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL && jac->kspupper != jac->head->ksp) {
899: PetscCall(MatDestroy(&jac->schur_user));
900: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
901: }
902: if (kspA != kspInner) PetscCall(KSPSetOperators(kspA, jac->mat[0], jac->pmat[0]));
903: if (kspUpper != kspA) PetscCall(KSPSetOperators(kspUpper, jac->mat[0], jac->pmat[0]));
904: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac)));
905: } else {
906: const char *Dprefix;
907: char schurprefix[256], schurmatprefix[256];
908: char schurtestoption[256];
909: MatNullSpace sp;
910: KSP kspt;
912: /* extract the A01 and A10 matrices */
913: ilink = jac->head;
914: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
915: if (jac->offdiag_use_amat) {
916: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
917: } else {
918: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
919: }
920: PetscCall(ISDestroy(&ccis));
921: ilink = ilink->next;
922: if (!flg) {
923: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
924: if (jac->offdiag_use_amat) {
925: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
926: } else {
927: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
928: }
929: PetscCall(ISDestroy(&ccis));
930: } else {
931: PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &isset, &flg));
932: if (isset && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C));
933: else PetscCall(MatCreateTranspose(jac->B, &jac->C));
934: }
935: /* Use mat[0] (diagonal block of Amat) preconditioned by pmat[0] to define Schur complement */
936: PetscCall(MatCreate(((PetscObject)jac->mat[0])->comm, &jac->schur));
937: PetscCall(MatSetType(jac->schur, MATSCHURCOMPLEMENT));
938: PetscCall(MatSchurComplementSetSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1]));
939: PetscCall(PetscSNPrintf(schurmatprefix, sizeof(schurmatprefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
940: PetscCall(MatSetOptionsPrefix(jac->schur, schurmatprefix));
941: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspt));
942: PetscCall(KSPSetOptionsPrefix(kspt, schurmatprefix));
944: /* Note: this is not true in general */
945: PetscCall(MatGetNullSpace(jac->mat[1], &sp));
946: if (sp) PetscCall(MatSetNullSpace(jac->schur, sp));
948: PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_inner_", ilink->splitname));
949: PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg));
950: if (flg) {
951: DM dmInner;
952: KSP kspInner;
953: PC pcInner;
955: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
956: PetscCall(KSPReset(kspInner));
957: PetscCall(KSPSetOperators(kspInner, jac->mat[0], jac->pmat[0]));
958: PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_inner_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
959: /* Indent this deeper to emphasize the "inner" nature of this solver. */
960: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner, (PetscObject)pc, 2));
961: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner->pc, (PetscObject)pc, 2));
962: PetscCall(KSPSetOptionsPrefix(kspInner, schurprefix));
964: /* Set DM for new solver */
965: PetscCall(KSPGetDM(jac->head->ksp, &dmInner));
966: PetscCall(KSPSetDM(kspInner, dmInner));
967: PetscCall(KSPSetDMActive(kspInner, PETSC_FALSE));
969: /* Defaults to PCKSP as preconditioner */
970: PetscCall(KSPGetPC(kspInner, &pcInner));
971: PetscCall(PCSetType(pcInner, PCKSP));
972: PetscCall(PCKSPSetKSP(pcInner, jac->head->ksp));
973: } else {
974: /* Use the outer solver for the inner solve, but revert the KSPPREONLY from PCFieldSplitSetFields_FieldSplit or
975: * PCFieldSplitSetIS_FieldSplit. We don't want KSPPREONLY because it makes the Schur complement inexact,
976: * preventing Schur complement reduction to be an accurate solve. Usually when an iterative solver is used for
977: * S = D - C A_inner^{-1} B, we expect S to be defined using an accurate definition of A_inner^{-1}, so we make
978: * GMRES the default. Note that it is also common to use PREONLY for S, in which case S may not be used
979: * directly, and the user is responsible for setting an inexact method for fieldsplit's A^{-1}. */
980: PetscCall(KSPSetType(jac->head->ksp, KSPGMRES));
981: PetscCall(MatSchurComplementSetKSP(jac->schur, jac->head->ksp));
982: }
983: PetscCall(KSPSetOperators(jac->head->ksp, jac->mat[0], jac->pmat[0]));
984: PetscCall(KSPSetFromOptions(jac->head->ksp));
985: PetscCall(MatSetFromOptions(jac->schur));
987: PetscCall(PetscObjectTypeCompare((PetscObject)jac->schur, MATSCHURCOMPLEMENT, &flg));
988: if (flg) { /* Need to do this otherwise PCSetUp_KSP will overwrite the amat of jac->head->ksp */
989: KSP kspInner;
990: PC pcInner;
992: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
993: PetscCall(KSPGetPC(kspInner, &pcInner));
994: PetscCall(PetscObjectTypeCompare((PetscObject)pcInner, PCKSP, &flg));
995: if (flg) {
996: KSP ksp;
998: PetscCall(PCKSPGetKSP(pcInner, &ksp));
999: if (ksp == jac->head->ksp) PetscCall(PCSetUseAmat(pcInner, PETSC_TRUE));
1000: }
1001: }
1002: PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_upper_", ilink->splitname));
1003: PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg));
1004: if (flg) {
1005: DM dmInner;
1007: PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_upper_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
1008: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspupper));
1009: PetscCall(KSPSetNestLevel(jac->kspupper, pc->kspnestlevel));
1010: PetscCall(KSPSetErrorIfNotConverged(jac->kspupper, pc->erroriffailure));
1011: PetscCall(KSPSetOptionsPrefix(jac->kspupper, schurprefix));
1012: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper, (PetscObject)pc, 1));
1013: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper->pc, (PetscObject)pc, 1));
1014: PetscCall(KSPGetDM(jac->head->ksp, &dmInner));
1015: PetscCall(KSPSetDM(jac->kspupper, dmInner));
1016: PetscCall(KSPSetDMActive(jac->kspupper, PETSC_FALSE));
1017: PetscCall(KSPSetFromOptions(jac->kspupper));
1018: PetscCall(KSPSetOperators(jac->kspupper, jac->mat[0], jac->pmat[0]));
1019: PetscCall(VecDuplicate(jac->head->x, &jac->head->z));
1020: } else {
1021: jac->kspupper = jac->head->ksp;
1022: PetscCall(PetscObjectReference((PetscObject)jac->head->ksp));
1023: }
1025: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp));
1026: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspschur));
1027: PetscCall(KSPSetNestLevel(jac->kspschur, pc->kspnestlevel));
1028: PetscCall(KSPSetErrorIfNotConverged(jac->kspschur, pc->erroriffailure));
1029: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspschur, (PetscObject)pc, 1));
1030: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) {
1031: PC pcschur;
1032: PetscCall(KSPGetPC(jac->kspschur, &pcschur));
1033: PetscCall(PCSetType(pcschur, PCNONE));
1034: /* Note: This is bad if there exist preconditioners for MATSCHURCOMPLEMENT */
1035: } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL) {
1036: if (jac->schurfactorization != PC_FIELDSPLIT_SCHUR_FACT_FULL || jac->kspupper != jac->head->ksp) PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1037: }
1038: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac)));
1039: PetscCall(KSPGetOptionsPrefix(jac->head->next->ksp, &Dprefix));
1040: PetscCall(KSPSetOptionsPrefix(jac->kspschur, Dprefix));
1041: /* propagate DM */
1042: {
1043: DM sdm;
1044: PetscCall(KSPGetDM(jac->head->next->ksp, &sdm));
1045: if (sdm) {
1046: PetscCall(KSPSetDM(jac->kspschur, sdm));
1047: PetscCall(KSPSetDMActive(jac->kspschur, PETSC_FALSE));
1048: }
1049: }
1050: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
1051: /* need to call this every time, since the jac->kspschur is freshly created, otherwise its options never get set */
1052: PetscCall(KSPSetFromOptions(jac->kspschur));
1053: }
1054: PetscCall(MatAssemblyBegin(jac->schur, MAT_FINAL_ASSEMBLY));
1055: PetscCall(MatAssemblyEnd(jac->schur, MAT_FINAL_ASSEMBLY));
1056: if (issym) PetscCall(MatSetOption(jac->schur, MAT_SYMMETRIC, PETSC_TRUE));
1057: if (isspd) PetscCall(MatSetOption(jac->schur, MAT_SPD, PETSC_TRUE));
1059: /* HACK: special support to forward L and Lp matrices that might be used by PCLSC */
1060: PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_L", ilink->splitname));
1061: PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, &LSC_L));
1062: if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, &LSC_L));
1063: if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_L", LSC_L));
1064: PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_Lp", ilink->splitname));
1065: PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, &LSC_L));
1066: if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, &LSC_L));
1067: if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_Lp", LSC_L));
1068: } else if (jac->type == PC_COMPOSITE_GKB) {
1069: IS ccis;
1070: PetscInt rstart, rend;
1072: PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use GKB preconditioner you must have exactly 2 fields");
1074: ilink = jac->head;
1076: /* When extracting off-diagonal submatrices, we take complements from this range */
1077: PetscCall(MatGetOwnershipRangeColumn(pc->mat, &rstart, &rend));
1079: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
1080: if (jac->offdiag_use_amat) {
1081: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
1082: } else {
1083: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
1084: }
1085: PetscCall(ISDestroy(&ccis));
1086: /* Create work vectors for GKB algorithm */
1087: PetscCall(VecDuplicate(ilink->x, &jac->u));
1088: PetscCall(VecDuplicate(ilink->x, &jac->Hu));
1089: PetscCall(VecDuplicate(ilink->x, &jac->w2));
1090: ilink = ilink->next;
1091: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
1092: if (jac->offdiag_use_amat) {
1093: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
1094: } else {
1095: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
1096: }
1097: PetscCall(ISDestroy(&ccis));
1098: /* Create work vectors for GKB algorithm */
1099: PetscCall(VecDuplicate(ilink->x, &jac->v));
1100: PetscCall(VecDuplicate(ilink->x, &jac->d));
1101: PetscCall(VecDuplicate(ilink->x, &jac->w1));
1102: PetscCall(MatGolubKahanComputeExplicitOperator(jac->mat[0], jac->B, jac->C, &jac->H, jac->gkbnu));
1103: PetscCall(PetscCalloc1(jac->gkbdelay, &jac->vecz));
1105: ilink = jac->head;
1106: PetscCall(KSPSetOperators(ilink->ksp, jac->H, jac->H));
1107: if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp));
1108: /* Create gkb_monitor context */
1109: if (jac->gkbmonitor) {
1110: PetscInt tablevel;
1111: PetscCall(PetscViewerCreate(PETSC_COMM_WORLD, &jac->gkbviewer));
1112: PetscCall(PetscViewerSetType(jac->gkbviewer, PETSCVIEWERASCII));
1113: PetscCall(PetscObjectGetTabLevel((PetscObject)ilink->ksp, &tablevel));
1114: PetscCall(PetscViewerASCIISetTab(jac->gkbviewer, tablevel));
1115: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)ilink->ksp, 1));
1116: }
1117: } else {
1118: /* set up the individual splits' PCs */
1119: i = 0;
1120: ilink = jac->head;
1121: while (ilink) {
1122: PetscCall(KSPSetOperators(ilink->ksp, jac->mat[i], jac->pmat[i]));
1123: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
1124: if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp));
1125: i++;
1126: ilink = ilink->next;
1127: }
1128: }
1130: /* Set coordinates to the sub PC objects whenever these are set */
1131: if (jac->coordinates_set) {
1132: PC pc_coords;
1133: if (jac->type == PC_COMPOSITE_SCHUR) {
1134: // Head is first block.
1135: PetscCall(KSPGetPC(jac->head->ksp, &pc_coords));
1136: PetscCall(PCSetCoordinates(pc_coords, jac->head->dim, jac->head->ndofs, jac->head->coords));
1137: // Second one is Schur block, but its KSP object is in kspschur.
1138: PetscCall(KSPGetPC(jac->kspschur, &pc_coords));
1139: PetscCall(PCSetCoordinates(pc_coords, jac->head->next->dim, jac->head->next->ndofs, jac->head->next->coords));
1140: } else if (jac->type == PC_COMPOSITE_GKB) {
1141: PetscCall(PetscInfo(pc, "Warning: Setting coordinates does nothing for the GKB Fieldpslit preconditioner\n"));
1142: } else {
1143: ilink = jac->head;
1144: while (ilink) {
1145: PetscCall(KSPGetPC(ilink->ksp, &pc_coords));
1146: PetscCall(PCSetCoordinates(pc_coords, ilink->dim, ilink->ndofs, ilink->coords));
1147: ilink = ilink->next;
1148: }
1149: }
1150: }
1152: jac->suboptionsset = PETSC_TRUE;
1153: PetscFunctionReturn(PETSC_SUCCESS);
1154: }
1156: static PetscErrorCode PCSetUpOnBlocks_FieldSplit_Schur(PC pc)
1157: {
1158: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1159: PC_FieldSplitLink ilinkA = jac->head;
1160: KSP kspA = ilinkA->ksp, kspUpper = jac->kspupper;
1162: PetscFunctionBegin;
1163: if (jac->schurfactorization == PC_FIELDSPLIT_SCHUR_FACT_FULL && kspUpper != kspA) {
1164: PetscCall(KSPSetUp(kspUpper));
1165: PetscCall(KSPSetUpOnBlocks(kspUpper));
1166: }
1167: PetscCall(KSPSetUp(kspA));
1168: PetscCall(KSPSetUpOnBlocks(kspA));
1169: if (jac->schurpre != PC_FIELDSPLIT_SCHUR_PRE_FULL) {
1170: PetscCall(KSPSetUp(jac->kspschur));
1171: PetscCall(KSPSetUpOnBlocks(jac->kspschur));
1172: } else if (kspUpper == kspA) {
1173: Mat A;
1174: PetscInt m, M, N;
1175: VecType vtype;
1176: PetscMemType mtype;
1177: PetscScalar *array;
1179: PetscCall(MatGetSize(jac->B, &M, &N));
1180: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1181: PetscCall(MatGetVecType(jac->B, &vtype));
1182: PetscCall(VecGetArrayAndMemType(ilinkA->x, &array, &mtype));
1183: PetscCall(VecRestoreArrayAndMemType(ilinkA->x, &array));
1184: if (PetscMemTypeHost(mtype) || (!PetscDefined(HAVE_CUDA) && !PetscDefined(HAVE_HIP))) PetscCall(PetscMalloc1(m * (N + 1), &array));
1185: #if PetscDefined(HAVE_CUDA)
1186: else if (PetscMemTypeCUDA(mtype)) PetscCallCUDA(cudaMalloc((void **)&array, sizeof(PetscScalar) * m * (N + 1)));
1187: #endif
1188: #if PetscDefined(HAVE_HIP)
1189: else if (PetscMemTypeHIP(mtype)) PetscCallHIP(hipMalloc((void **)&array, sizeof(PetscScalar) * m * (N + 1)));
1190: #endif
1191: PetscCall(MatCreateDenseFromVecType(PetscObjectComm((PetscObject)jac->schur), vtype, m, PETSC_DECIDE, M, N + 1, -1, array, &A)); // number of columns of the Schur complement plus one
1192: PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", (PetscObject)A));
1193: PetscCall(MatDestroy(&A));
1194: }
1195: PetscFunctionReturn(PETSC_SUCCESS);
1196: }
1198: static PetscErrorCode PCSetUpOnBlocks_FieldSplit(PC pc)
1199: {
1200: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1201: PC_FieldSplitLink ilink = jac->head;
1203: PetscFunctionBegin;
1204: while (ilink) {
1205: PetscCall(KSPSetUp(ilink->ksp));
1206: PetscCall(KSPSetUpOnBlocks(ilink->ksp));
1207: ilink = ilink->next;
1208: }
1209: PetscFunctionReturn(PETSC_SUCCESS);
1210: }
1212: static PetscErrorCode PCSetUpOnBlocks_FieldSplit_GKB(PC pc)
1213: {
1214: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1215: PC_FieldSplitLink ilinkA = jac->head;
1216: KSP ksp = ilinkA->ksp;
1218: PetscFunctionBegin;
1219: PetscCall(KSPSetUp(ksp));
1220: PetscCall(KSPSetUpOnBlocks(ksp));
1221: PetscFunctionReturn(PETSC_SUCCESS);
1222: }
1224: static PetscErrorCode PCApply_FieldSplit_Schur(PC pc, Vec x, Vec y)
1225: {
1226: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1227: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1228: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1229: Mat AinvB = NULL;
1230: PetscInt N, P;
1232: PetscFunctionBegin;
1233: switch (jac->schurfactorization) {
1234: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1235: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1236: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1237: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1238: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1239: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1240: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1241: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1242: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1243: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1244: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1245: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1246: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1247: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1248: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1249: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1250: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1251: PetscCall(VecScale(ilinkD->y, jac->schurscale));
1252: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1253: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1254: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1255: break;
1256: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1257: /* [A00 0; A10 S], suitable for left preconditioning */
1258: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1259: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1260: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1261: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1262: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1263: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1264: PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x));
1265: PetscCall(VecScale(ilinkD->x, -1.));
1266: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1267: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1268: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1269: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1270: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1271: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1272: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1273: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1274: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1275: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1276: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1277: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1278: break;
1279: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1280: /* [A00 A01; 0 S], suitable for right preconditioning */
1281: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1282: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1283: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1284: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1285: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1286: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1287: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1288: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1289: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->x));
1290: PetscCall(VecScale(ilinkA->x, -1.));
1291: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1292: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1293: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1294: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1295: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1296: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1297: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1298: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1299: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1300: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1301: break;
1302: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1303: /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1] */
1304: PetscCall(MatGetSize(jac->B, NULL, &P));
1305: N = P;
1306: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1307: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1308: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL));
1309: if (kspUpper == kspA) {
1310: PetscCall(PetscObjectQuery((PetscObject)jac->schur, "AinvB", (PetscObject *)&AinvB));
1311: if (AinvB) {
1312: PetscCall(MatGetSize(AinvB, NULL, &N));
1313: if (N > P) { // first time PCApply_FieldSplit_Schur() is called
1314: PetscMemType mtype;
1315: Vec c = NULL;
1316: PetscScalar *array;
1317: PetscInt m, M;
1319: PetscCall(MatGetSize(jac->B, &M, NULL));
1320: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1321: PetscCall(MatDenseGetArrayAndMemType(AinvB, &array, &mtype));
1322: if (PetscMemTypeHost(mtype) || (!PetscDefined(HAVE_CUDA) && !PetscDefined(HAVE_HIP))) PetscCall(VecCreateMPIWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1323: #if PetscDefined(HAVE_CUDA)
1324: else if (PetscMemTypeCUDA(mtype)) PetscCall(VecCreateMPICUDAWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1325: #endif
1326: #if PetscDefined(HAVE_HIP)
1327: else if (PetscMemTypeHIP(mtype)) PetscCall(VecCreateMPIHIPWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1328: #endif
1329: PetscCall(MatDenseRestoreArrayAndMemType(AinvB, &array));
1330: PetscCall(VecCopy(ilinkA->x, c));
1331: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1332: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, jac->schur_user));
1333: PetscCall(VecCopy(c, ilinkA->y)); // retrieve the solution as the last column of the composed Mat
1334: PetscCall(VecDestroy(&c));
1335: }
1336: }
1337: }
1338: if (N == P) PetscCall(KSPSolve(kspLower, ilinkA->x, ilinkA->y));
1339: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->y));
1340: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL));
1341: PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x));
1342: PetscCall(VecScale(ilinkD->x, -1.0));
1343: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1344: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1346: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1347: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1348: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1349: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1350: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1351: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1352: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1354: if (kspUpper == kspA) {
1355: if (!AinvB) {
1356: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->y));
1357: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1358: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1359: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1360: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1361: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1362: } else PetscCall(MatMultAdd(AinvB, ilinkD->y, ilinkA->y, ilinkA->y));
1363: } else {
1364: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1365: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1366: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1367: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->x));
1368: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1369: PetscCall(KSPSolve(kspUpper, ilinkA->x, ilinkA->z));
1370: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->z));
1371: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1372: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1373: }
1374: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1375: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1376: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1377: }
1378: PetscFunctionReturn(PETSC_SUCCESS);
1379: }
1381: static PetscErrorCode PCApplyTranspose_FieldSplit_Schur(PC pc, Vec x, Vec y)
1382: {
1383: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1384: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1385: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1387: PetscFunctionBegin;
1388: switch (jac->schurfactorization) {
1389: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1390: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1391: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1392: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1393: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1394: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1395: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1396: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1397: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1398: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1399: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1400: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1401: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1402: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1403: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1404: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1405: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1406: PetscCall(VecScale(ilinkD->y, jac->schurscale));
1407: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1408: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1409: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1410: break;
1411: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1412: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1413: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1414: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1415: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1416: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1417: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1418: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1419: PetscCall(VecScale(ilinkD->x, -1.));
1420: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1421: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1422: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1423: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1424: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1425: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1426: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1427: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1428: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1429: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1430: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1431: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1432: break;
1433: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1434: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1435: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1436: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1437: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1438: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1439: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1440: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1441: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1442: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1443: PetscCall(VecScale(ilinkA->x, -1.));
1444: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1445: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1446: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1447: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1448: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1449: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1450: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1451: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1452: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1453: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1454: break;
1455: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1456: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1457: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1458: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1459: PetscCall(KSPSolveTranspose(kspUpper, ilinkA->x, ilinkA->y));
1460: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->y));
1461: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1462: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1463: PetscCall(VecScale(ilinkD->x, -1.0));
1464: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1465: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1467: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1468: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1469: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1470: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1471: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1472: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1473: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1475: if (kspLower == kspA) {
1476: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->y));
1477: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1478: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1479: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1480: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1481: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1482: } else {
1483: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1484: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1485: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1486: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1487: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1488: PetscCall(KSPSolveTranspose(kspLower, ilinkA->x, ilinkA->z));
1489: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->z));
1490: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1491: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1492: }
1493: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1494: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1495: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1496: }
1497: PetscFunctionReturn(PETSC_SUCCESS);
1498: }
1500: #define FieldSplitSplitSolveAdd(ilink, xx, yy) \
1501: ((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) || \
1502: 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) || \
1503: VecScatterEnd(ilink->sctx, ilink->y, yy, ADD_VALUES, SCATTER_REVERSE)))
1505: static PetscErrorCode PCApply_FieldSplit(PC pc, Vec x, Vec y)
1506: {
1507: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1508: PC_FieldSplitLink ilink = jac->head;
1509: PetscInt cnt, bs;
1511: PetscFunctionBegin;
1512: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1513: PetscBool matnest;
1515: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1516: if (jac->defaultsplit && !matnest) {
1517: PetscCall(VecGetBlockSize(x, &bs));
1518: 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);
1519: PetscCall(VecGetBlockSize(y, &bs));
1520: 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);
1521: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1522: while (ilink) {
1523: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1524: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1525: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1526: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1527: ilink = ilink->next;
1528: }
1529: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1530: } else {
1531: PetscCall(VecSet(y, 0.0));
1532: while (ilink) {
1533: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1534: ilink = ilink->next;
1535: }
1536: }
1537: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) {
1538: PetscCall(VecSet(y, 0.0));
1539: /* solve on first block for first block variables */
1540: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1541: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1542: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1543: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1544: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1545: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1546: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1547: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1549: /* compute the residual only onto second block variables using first block variables */
1550: PetscCall(MatMult(jac->Afield[1], ilink->y, ilink->next->x));
1551: ilink = ilink->next;
1552: PetscCall(VecScale(ilink->x, -1.0));
1553: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1554: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1556: /* solve on second block variables */
1557: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1558: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1559: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1560: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1561: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1562: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1563: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1564: if (!jac->w1) {
1565: PetscCall(VecDuplicate(x, &jac->w1));
1566: PetscCall(VecDuplicate(x, &jac->w2));
1567: }
1568: PetscCall(VecSet(y, 0.0));
1569: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1570: cnt = 1;
1571: while (ilink->next) {
1572: ilink = ilink->next;
1573: /* compute the residual only over the part of the vector needed */
1574: PetscCall(MatMult(jac->Afield[cnt++], y, ilink->x));
1575: PetscCall(VecScale(ilink->x, -1.0));
1576: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1577: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1578: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1579: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1580: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1581: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1582: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1583: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1584: }
1585: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1586: cnt -= 2;
1587: while (ilink->previous) {
1588: ilink = ilink->previous;
1589: /* compute the residual only over the part of the vector needed */
1590: PetscCall(MatMult(jac->Afield[cnt--], y, ilink->x));
1591: PetscCall(VecScale(ilink->x, -1.0));
1592: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1593: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1594: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1595: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1596: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1597: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1598: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1599: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1600: }
1601: }
1602: } else SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Unsupported or unknown composition %d", (int)jac->type);
1603: PetscFunctionReturn(PETSC_SUCCESS);
1604: }
1606: static PetscErrorCode PCApply_FieldSplit_GKB(PC pc, Vec x, Vec y)
1607: {
1608: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1609: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1610: KSP ksp = ilinkA->ksp;
1611: Vec u, v, Hu, d, work1, work2;
1612: PetscScalar alpha, z, nrmz2, *vecz;
1613: PetscReal lowbnd, nu, beta;
1614: PetscInt j, iterGKB;
1616: PetscFunctionBegin;
1617: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1618: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1619: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1620: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1622: u = jac->u;
1623: v = jac->v;
1624: Hu = jac->Hu;
1625: d = jac->d;
1626: work1 = jac->w1;
1627: work2 = jac->w2;
1628: vecz = jac->vecz;
1630: /* Change RHS to comply with matrix regularization H = A + nu*B*B' */
1631: /* Add q = q + nu*B*b */
1632: if (jac->gkbnu) {
1633: nu = jac->gkbnu;
1634: PetscCall(VecScale(ilinkD->x, jac->gkbnu));
1635: PetscCall(MatMultAdd(jac->B, ilinkD->x, ilinkA->x, ilinkA->x)); /* q = q + nu*B*b */
1636: } else {
1637: /* Situation when no augmented Lagrangian is used. Then we set inner */
1638: /* matrix N = I in [Ar13], and thus nu = 1. */
1639: nu = 1;
1640: }
1642: /* Transform rhs from [q,tilde{b}] to [0,b] */
1643: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1644: PetscCall(KSPSolve(ksp, ilinkA->x, ilinkA->y));
1645: PetscCall(KSPCheckSolve(ksp, pc, ilinkA->y));
1646: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1647: PetscCall(MatMultHermitianTranspose(jac->B, ilinkA->y, work1));
1648: PetscCall(VecAXPBY(work1, 1.0 / nu, -1.0, ilinkD->x)); /* c = b - B'*x */
1650: /* First step of algorithm */
1651: PetscCall(VecNorm(work1, NORM_2, &beta)); /* beta = sqrt(nu*c'*c)*/
1652: KSPCheckDot(ksp, beta);
1653: beta = PetscSqrtReal(nu) * beta;
1654: PetscCall(VecAXPBY(v, nu / beta, 0.0, work1)); /* v = nu/beta *c */
1655: PetscCall(MatMult(jac->B, v, work2)); /* u = H^{-1}*B*v */
1656: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1657: PetscCall(KSPSolve(ksp, work2, u));
1658: PetscCall(KSPCheckSolve(ksp, pc, u));
1659: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1660: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1661: PetscCall(VecDot(Hu, u, &alpha));
1662: KSPCheckDot(ksp, alpha);
1663: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1664: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1665: PetscCall(VecScale(u, 1.0 / alpha));
1666: PetscCall(VecAXPBY(d, 1.0 / alpha, 0.0, v)); /* v = nu/beta *c */
1668: z = beta / alpha;
1669: vecz[1] = z;
1671: /* Computation of first iterate x(1) and p(1) */
1672: PetscCall(VecAXPY(ilinkA->y, z, u));
1673: PetscCall(VecCopy(d, ilinkD->y));
1674: PetscCall(VecScale(ilinkD->y, -z));
1676: iterGKB = 1;
1677: lowbnd = 2 * jac->gkbtol;
1678: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1680: while (iterGKB < jac->gkbmaxit && lowbnd > jac->gkbtol) {
1681: iterGKB += 1;
1682: PetscCall(MatMultHermitianTranspose(jac->B, u, work1)); /* v <- nu*(B'*u-alpha/nu*v) */
1683: PetscCall(VecAXPBY(v, nu, -alpha, work1));
1684: PetscCall(VecNorm(v, NORM_2, &beta)); /* beta = sqrt(nu)*v'*v */
1685: beta = beta / PetscSqrtReal(nu);
1686: PetscCall(VecScale(v, 1.0 / beta));
1687: PetscCall(MatMult(jac->B, v, work2)); /* u <- H^{-1}*(B*v-beta*H*u) */
1688: PetscCall(MatMult(jac->H, u, Hu));
1689: PetscCall(VecAXPY(work2, -beta, Hu));
1690: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1691: PetscCall(KSPSolve(ksp, work2, u));
1692: PetscCall(KSPCheckSolve(ksp, pc, u));
1693: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1694: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1695: PetscCall(VecDot(Hu, u, &alpha));
1696: KSPCheckDot(ksp, alpha);
1697: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1698: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1699: PetscCall(VecScale(u, 1.0 / alpha));
1701: z = -beta / alpha * z; /* z <- beta/alpha*z */
1702: vecz[0] = z;
1704: /* Computation of new iterate x(i+1) and p(i+1) */
1705: PetscCall(VecAXPBY(d, 1.0 / alpha, -beta / alpha, v)); /* d = (v-beta*d)/alpha */
1706: PetscCall(VecAXPY(ilinkA->y, z, u)); /* r = r + z*u */
1707: PetscCall(VecAXPY(ilinkD->y, -z, d)); /* p = p - z*d */
1708: PetscCall(MatMult(jac->H, ilinkA->y, Hu)); /* ||u||_H = u'*H*u */
1709: PetscCall(VecDot(Hu, ilinkA->y, &nrmz2));
1711: /* Compute Lower Bound estimate */
1712: if (iterGKB > jac->gkbdelay) {
1713: lowbnd = 0.0;
1714: for (j = 0; j < jac->gkbdelay; j++) lowbnd += PetscAbsScalar(vecz[j] * vecz[j]);
1715: lowbnd = PetscSqrtReal(lowbnd / PetscAbsScalar(nrmz2));
1716: }
1718: for (j = 0; j < jac->gkbdelay - 1; j++) vecz[jac->gkbdelay - j - 1] = vecz[jac->gkbdelay - j - 2];
1719: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1720: }
1722: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1723: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1724: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1725: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1726: PetscFunctionReturn(PETSC_SUCCESS);
1727: }
1729: #define FieldSplitSplitSolveAddTranspose(ilink, xx, yy) \
1730: ((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) || \
1731: 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) || \
1732: VecScatterEnd(ilink->sctx, ilink->x, yy, ADD_VALUES, SCATTER_REVERSE)))
1734: static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc, Vec x, Vec y)
1735: {
1736: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1737: PC_FieldSplitLink ilink = jac->head;
1738: PetscInt bs;
1740: PetscFunctionBegin;
1741: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1742: PetscBool matnest;
1744: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1745: if (jac->defaultsplit && !matnest) {
1746: PetscCall(VecGetBlockSize(x, &bs));
1747: 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);
1748: PetscCall(VecGetBlockSize(y, &bs));
1749: 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);
1750: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1751: while (ilink) {
1752: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1753: PetscCall(KSPSolveTranspose(ilink->ksp, ilink->x, ilink->y));
1754: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1755: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1756: ilink = ilink->next;
1757: }
1758: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1759: } else {
1760: PetscCall(VecSet(y, 0.0));
1761: while (ilink) {
1762: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
1763: ilink = ilink->next;
1764: }
1765: }
1766: } else {
1767: if (!jac->w1) {
1768: PetscCall(VecDuplicate(x, &jac->w1));
1769: PetscCall(VecDuplicate(x, &jac->w2));
1770: }
1771: PetscCall(VecSet(y, 0.0));
1772: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1773: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
1774: while (ilink->next) {
1775: ilink = ilink->next;
1776: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
1777: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
1778: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
1779: }
1780: while (ilink->previous) {
1781: ilink = ilink->previous;
1782: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
1783: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
1784: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
1785: }
1786: } else {
1787: while (ilink->next) { /* get to last entry in linked list */
1788: ilink = ilink->next;
1789: }
1790: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
1791: while (ilink->previous) {
1792: ilink = ilink->previous;
1793: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
1794: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
1795: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
1796: }
1797: }
1798: }
1799: PetscFunctionReturn(PETSC_SUCCESS);
1800: }
1802: static PetscErrorCode PCReset_FieldSplit(PC pc)
1803: {
1804: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1805: PC_FieldSplitLink ilink = jac->head, next;
1807: PetscFunctionBegin;
1808: while (ilink) {
1809: PetscCall(KSPDestroy(&ilink->ksp));
1810: PetscCall(VecDestroy(&ilink->x));
1811: PetscCall(VecDestroy(&ilink->y));
1812: PetscCall(VecDestroy(&ilink->z));
1813: PetscCall(VecScatterDestroy(&ilink->sctx));
1814: PetscCall(ISDestroy(&ilink->is));
1815: PetscCall(ISDestroy(&ilink->is_col));
1816: PetscCall(PetscFree(ilink->splitname));
1817: PetscCall(PetscFree(ilink->fields));
1818: PetscCall(PetscFree(ilink->fields_col));
1819: next = ilink->next;
1820: PetscCall(PetscFree(ilink));
1821: ilink = next;
1822: }
1823: jac->head = NULL;
1824: PetscCall(PetscFree2(jac->x, jac->y));
1825: if (jac->mat && jac->mat != jac->pmat) {
1826: PetscCall(MatDestroyMatrices(jac->nsplits, &jac->mat));
1827: } else if (jac->mat) {
1828: jac->mat = NULL;
1829: }
1830: if (jac->pmat) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->pmat));
1831: if (jac->Afield) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->Afield));
1832: jac->nsplits = 0;
1833: PetscCall(VecDestroy(&jac->w1));
1834: PetscCall(VecDestroy(&jac->w2));
1835: if (jac->schur) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", NULL));
1836: PetscCall(MatDestroy(&jac->schur));
1837: PetscCall(MatDestroy(&jac->schurp));
1838: PetscCall(MatDestroy(&jac->schur_user));
1839: PetscCall(KSPDestroy(&jac->kspschur));
1840: PetscCall(KSPDestroy(&jac->kspupper));
1841: PetscCall(MatDestroy(&jac->B));
1842: PetscCall(MatDestroy(&jac->C));
1843: PetscCall(MatDestroy(&jac->H));
1844: PetscCall(VecDestroy(&jac->u));
1845: PetscCall(VecDestroy(&jac->v));
1846: PetscCall(VecDestroy(&jac->Hu));
1847: PetscCall(VecDestroy(&jac->d));
1848: PetscCall(PetscFree(jac->vecz));
1849: PetscCall(PetscViewerDestroy(&jac->gkbviewer));
1850: jac->isrestrict = PETSC_FALSE;
1851: PetscFunctionReturn(PETSC_SUCCESS);
1852: }
1854: static PetscErrorCode PCDestroy_FieldSplit(PC pc)
1855: {
1856: PetscFunctionBegin;
1857: PetscCall(PCReset_FieldSplit(pc));
1858: PetscCall(PetscFree(pc->data));
1859: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", NULL));
1860: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", NULL));
1861: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", NULL));
1862: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", NULL));
1863: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", NULL));
1864: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", NULL));
1865: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", NULL));
1866: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
1867: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
1868: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
1869: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
1870: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
1871: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
1872: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
1873: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
1874: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
1875: PetscFunctionReturn(PETSC_SUCCESS);
1876: }
1878: static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc, PetscOptionItems PetscOptionsObject)
1879: {
1880: PetscInt bs;
1881: PetscBool flg;
1882: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1883: PCCompositeType ctype;
1885: PetscFunctionBegin;
1886: PetscOptionsHeadBegin(PetscOptionsObject, "FieldSplit options");
1887: PetscCall(PetscOptionsBool("-pc_fieldsplit_dm_splits", "Whether to use DMCreateFieldDecomposition() for splits", "PCFieldSplitSetDMSplits", jac->dm_splits, &jac->dm_splits, NULL));
1888: PetscCall(PetscOptionsInt("-pc_fieldsplit_block_size", "Blocksize that defines number of fields", "PCFieldSplitSetBlockSize", jac->bs, &bs, &flg));
1889: if (flg) PetscCall(PCFieldSplitSetBlockSize(pc, bs));
1890: jac->diag_use_amat = pc->useAmat;
1891: 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));
1892: jac->offdiag_use_amat = pc->useAmat;
1893: 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));
1894: PetscCall(PetscOptionsBool("-pc_fieldsplit_detect_saddle_point", "Form 2-way split by detecting zero diagonal entries", "PCFieldSplitSetDetectSaddlePoint", jac->detect, &jac->detect, NULL));
1895: PetscCall(PCFieldSplitSetDetectSaddlePoint(pc, jac->detect)); /* Sets split type and Schur PC type */
1896: PetscCall(PetscOptionsEnum("-pc_fieldsplit_type", "Type of composition", "PCFieldSplitSetType", PCCompositeTypes, (PetscEnum)jac->type, (PetscEnum *)&ctype, &flg));
1897: if (flg) PetscCall(PCFieldSplitSetType(pc, ctype));
1898: /* Only setup fields once */
1899: if (jac->bs > 0 && jac->nsplits == 0) {
1900: /* only allow user to set fields from command line.
1901: otherwise user can set them in PCFieldSplitSetDefaults() */
1902: PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc));
1903: if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n"));
1904: }
1905: if (jac->type == PC_COMPOSITE_SCHUR) {
1906: PetscCall(PetscOptionsGetEnum(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_schur_factorization_type", PCFieldSplitSchurFactTypes, (PetscEnum *)&jac->schurfactorization, &flg));
1907: if (flg) PetscCall(PetscInfo(pc, "Deprecated use of -pc_fieldsplit_schur_factorization_type\n"));
1908: 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));
1909: PetscCall(PetscOptionsEnum("-pc_fieldsplit_schur_precondition", "How to build preconditioner for Schur complement", "PCFieldSplitSetSchurPre", PCFieldSplitSchurPreTypes, (PetscEnum)jac->schurpre, (PetscEnum *)&jac->schurpre, NULL));
1910: PetscCall(PetscOptionsScalar("-pc_fieldsplit_schur_scale", "Scale Schur complement", "PCFieldSplitSetSchurScale", jac->schurscale, &jac->schurscale, NULL));
1911: } else if (jac->type == PC_COMPOSITE_GKB) {
1912: PetscCall(PetscOptionsReal("-pc_fieldsplit_gkb_tol", "The tolerance for the lower bound stopping criterion", "PCFieldSplitSetGKBTol", jac->gkbtol, &jac->gkbtol, NULL));
1913: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_delay", "The delay value for lower bound criterion", "PCFieldSplitSetGKBDelay", jac->gkbdelay, &jac->gkbdelay, NULL));
1914: PetscCall(PetscOptionsBoundedReal("-pc_fieldsplit_gkb_nu", "Parameter in augmented Lagrangian approach", "PCFieldSplitSetGKBNu", jac->gkbnu, &jac->gkbnu, NULL, 0.0));
1915: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_maxit", "Maximum allowed number of iterations", "PCFieldSplitSetGKBMaxit", jac->gkbmaxit, &jac->gkbmaxit, NULL));
1916: PetscCall(PetscOptionsBool("-pc_fieldsplit_gkb_monitor", "Prints number of GKB iterations and error", "PCFieldSplitGKB", jac->gkbmonitor, &jac->gkbmonitor, NULL));
1917: }
1918: /*
1919: In the initial call to this routine the sub-solver data structures do not exist so we cannot call KSPSetFromOptions() on them yet.
1920: 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
1921: is called on the outer solver in case changes were made in the options database
1923: 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()
1924: 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.
1925: Without this extra check test p2p1fetidp_olof_full and others fail with incorrect matrix types.
1927: There could be a negative side effect of calling the KSPSetFromOptions() below.
1929: If one captured the PetscObjectState of the options database one could skip these calls if the database has not changed from the previous call
1930: */
1931: if (jac->issetup) {
1932: PC_FieldSplitLink ilink = jac->head;
1933: if (jac->type == PC_COMPOSITE_SCHUR) {
1934: if (jac->kspupper && jac->kspupper->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspupper));
1935: if (jac->kspschur && jac->kspschur->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspschur));
1936: }
1937: while (ilink) {
1938: if (ilink->ksp->totalits > 0) PetscCall(KSPSetFromOptions(ilink->ksp));
1939: ilink = ilink->next;
1940: }
1941: }
1942: PetscOptionsHeadEnd();
1943: PetscFunctionReturn(PETSC_SUCCESS);
1944: }
1946: static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc, const char splitname[], PetscInt n, const PetscInt *fields, const PetscInt *fields_col)
1947: {
1948: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1949: PC_FieldSplitLink ilink, next = jac->head;
1950: char prefix[128];
1951: PetscInt i;
1952: PetscLogEvent nse;
1954: PetscFunctionBegin;
1955: if (jac->splitdefined) {
1956: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
1957: PetscFunctionReturn(PETSC_SUCCESS);
1958: }
1959: for (i = 0; i < n; i++) PetscCheck(fields[i] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", fields[i]);
1960: PetscCall(PetscNew(&ilink));
1961: if (splitname) {
1962: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
1963: } else {
1964: PetscCall(PetscMalloc1(3, &ilink->splitname));
1965: PetscCall(PetscSNPrintf(ilink->splitname, 2, "%" PetscInt_FMT, jac->nsplits));
1966: }
1967: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
1968: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
1969: PetscCall(PetscMalloc1(n, &ilink->fields));
1970: PetscCall(PetscArraycpy(ilink->fields, fields, n));
1971: PetscCall(PetscMalloc1(n, &ilink->fields_col));
1972: PetscCall(PetscArraycpy(ilink->fields_col, fields_col, n));
1974: ilink->nfields = n;
1975: ilink->next = NULL;
1976: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
1977: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
1978: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
1979: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
1980: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
1982: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
1983: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
1985: if (!next) {
1986: jac->head = ilink;
1987: ilink->previous = NULL;
1988: } else {
1989: while (next->next) next = next->next;
1990: next->next = ilink;
1991: ilink->previous = next;
1992: }
1993: jac->nsplits++;
1994: PetscFunctionReturn(PETSC_SUCCESS);
1995: }
1997: static PetscErrorCode PCFieldSplitSchurGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
1998: {
1999: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2001: PetscFunctionBegin;
2002: *subksp = NULL;
2003: if (n) *n = 0;
2004: if (jac->type == PC_COMPOSITE_SCHUR) {
2005: PetscInt nn;
2007: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitSchurGetSubKSP()");
2008: PetscCheck(jac->nsplits == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unexpected number of splits %" PetscInt_FMT " != 2", jac->nsplits);
2009: nn = jac->nsplits + (jac->kspupper != jac->head->ksp ? 1 : 0);
2010: PetscCall(PetscMalloc1(nn, subksp));
2011: (*subksp)[0] = jac->head->ksp;
2012: (*subksp)[1] = jac->kspschur;
2013: if (jac->kspupper != jac->head->ksp) (*subksp)[2] = jac->kspupper;
2014: if (n) *n = nn;
2015: }
2016: PetscFunctionReturn(PETSC_SUCCESS);
2017: }
2019: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc, PetscInt *n, KSP **subksp)
2020: {
2021: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2023: PetscFunctionBegin;
2024: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitGetSubKSP()");
2025: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2026: PetscCall(MatSchurComplementGetKSP(jac->schur, *subksp));
2028: (*subksp)[1] = jac->kspschur;
2029: if (n) *n = jac->nsplits;
2030: PetscFunctionReturn(PETSC_SUCCESS);
2031: }
2033: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
2034: {
2035: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2036: PetscInt cnt = 0;
2037: PC_FieldSplitLink ilink = jac->head;
2039: PetscFunctionBegin;
2040: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2041: while (ilink) {
2042: (*subksp)[cnt++] = ilink->ksp;
2043: ilink = ilink->next;
2044: }
2045: 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);
2046: if (n) *n = jac->nsplits;
2047: PetscFunctionReturn(PETSC_SUCCESS);
2048: }
2050: /*@
2051: PCFieldSplitRestrictIS - Restricts the fieldsplit `IS`s to be within a given `IS`.
2053: Input Parameters:
2054: + pc - the preconditioner context
2055: - isy - the index set that defines the indices to which the fieldsplit is to be restricted
2057: Level: advanced
2059: Developer Notes:
2060: It seems the resulting `IS`s will not cover the entire space, so
2061: how can they define a convergent preconditioner? Needs explaining.
2063: .seealso: [](sec_block_matrices), `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2064: @*/
2065: PetscErrorCode PCFieldSplitRestrictIS(PC pc, IS isy)
2066: {
2067: PetscFunctionBegin;
2070: PetscTryMethod(pc, "PCFieldSplitRestrictIS_C", (PC, IS), (pc, isy));
2071: PetscFunctionReturn(PETSC_SUCCESS);
2072: }
2074: static PetscErrorCode PCFieldSplitRestrictIS_FieldSplit(PC pc, IS isy)
2075: {
2076: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2077: PC_FieldSplitLink ilink = jac->head, next;
2078: PetscInt localsize, size, sizez, i;
2079: const PetscInt *ind, *indz;
2080: PetscInt *indc, *indcz;
2081: PetscBool flg;
2083: PetscFunctionBegin;
2084: PetscCall(ISGetLocalSize(isy, &localsize));
2085: PetscCallMPI(MPI_Scan(&localsize, &size, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)isy)));
2086: size -= localsize;
2087: while (ilink) {
2088: IS isrl, isr;
2089: PC subpc;
2090: PetscCall(ISEmbed(ilink->is, isy, PETSC_TRUE, &isrl));
2091: PetscCall(ISGetLocalSize(isrl, &localsize));
2092: PetscCall(PetscMalloc1(localsize, &indc));
2093: PetscCall(ISGetIndices(isrl, &ind));
2094: PetscCall(PetscArraycpy(indc, ind, localsize));
2095: PetscCall(ISRestoreIndices(isrl, &ind));
2096: PetscCall(ISDestroy(&isrl));
2097: for (i = 0; i < localsize; i++) *(indc + i) += size;
2098: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)isy), localsize, indc, PETSC_OWN_POINTER, &isr));
2099: PetscCall(PetscObjectReference((PetscObject)isr));
2100: PetscCall(ISDestroy(&ilink->is));
2101: ilink->is = isr;
2102: PetscCall(PetscObjectReference((PetscObject)isr));
2103: PetscCall(ISDestroy(&ilink->is_col));
2104: ilink->is_col = isr;
2105: PetscCall(ISDestroy(&isr));
2106: PetscCall(KSPGetPC(ilink->ksp, &subpc));
2107: PetscCall(PetscObjectTypeCompare((PetscObject)subpc, PCFIELDSPLIT, &flg));
2108: if (flg) {
2109: IS iszl, isz;
2110: MPI_Comm comm;
2111: PetscCall(ISGetLocalSize(ilink->is, &localsize));
2112: comm = PetscObjectComm((PetscObject)ilink->is);
2113: PetscCall(ISEmbed(isy, ilink->is, PETSC_TRUE, &iszl));
2114: PetscCallMPI(MPI_Scan(&localsize, &sizez, 1, MPIU_INT, MPI_SUM, comm));
2115: sizez -= localsize;
2116: PetscCall(ISGetLocalSize(iszl, &localsize));
2117: PetscCall(PetscMalloc1(localsize, &indcz));
2118: PetscCall(ISGetIndices(iszl, &indz));
2119: PetscCall(PetscArraycpy(indcz, indz, localsize));
2120: PetscCall(ISRestoreIndices(iszl, &indz));
2121: PetscCall(ISDestroy(&iszl));
2122: for (i = 0; i < localsize; i++) *(indcz + i) += sizez;
2123: PetscCall(ISCreateGeneral(comm, localsize, indcz, PETSC_OWN_POINTER, &isz));
2124: PetscCall(PCFieldSplitRestrictIS(subpc, isz));
2125: PetscCall(ISDestroy(&isz));
2126: }
2127: next = ilink->next;
2128: ilink = next;
2129: }
2130: jac->isrestrict = PETSC_TRUE;
2131: PetscFunctionReturn(PETSC_SUCCESS);
2132: }
2134: static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc, const char splitname[], IS is)
2135: {
2136: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2137: PC_FieldSplitLink ilink, next = jac->head;
2138: char prefix[128];
2139: PetscLogEvent nse;
2141: PetscFunctionBegin;
2142: if (jac->splitdefined) {
2143: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
2144: PetscFunctionReturn(PETSC_SUCCESS);
2145: }
2146: PetscCall(PetscNew(&ilink));
2147: if (splitname) {
2148: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
2149: } else {
2150: PetscCall(PetscMalloc1(8, &ilink->splitname));
2151: PetscCall(PetscSNPrintf(ilink->splitname, 7, "%" PetscInt_FMT, jac->nsplits));
2152: }
2153: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
2154: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
2155: PetscCall(PetscObjectReference((PetscObject)is));
2156: PetscCall(ISDestroy(&ilink->is));
2157: ilink->is = is;
2158: PetscCall(PetscObjectReference((PetscObject)is));
2159: PetscCall(ISDestroy(&ilink->is_col));
2160: ilink->is_col = is;
2161: ilink->next = NULL;
2162: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
2163: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
2164: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
2165: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
2166: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
2168: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
2169: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
2171: if (!next) {
2172: jac->head = ilink;
2173: ilink->previous = NULL;
2174: } else {
2175: while (next->next) next = next->next;
2176: next->next = ilink;
2177: ilink->previous = next;
2178: }
2179: jac->nsplits++;
2180: PetscFunctionReturn(PETSC_SUCCESS);
2181: }
2183: /*@
2184: PCFieldSplitSetFields - Sets the fields that define one particular split in `PCFIELDSPLIT`
2186: Logically Collective
2188: Input Parameters:
2189: + pc - the preconditioner context
2190: . splitname - name of this split, if `NULL` the number of the split is used
2191: . n - the number of fields in this split
2192: . fields - the fields in this split
2193: - fields_col - generally the same as `fields`, if it does not match `fields` then the submatrix that is solved for this set of fields comes from an off-diagonal block
2194: of the matrix and `fields_col` provides the column indices for that block
2196: Options Database Key:
2197: . -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the `%d`'th split
2199: Level: intermediate
2201: Notes:
2202: Use `PCFieldSplitSetIS()` to set a general set of indices as a split.
2204: If the matrix used to construct the preconditioner is `MATNEST` then field i refers to the `is_row[i]` `IS` passed to `MatCreateNest()`.
2206: If the matrix used to construct the preconditioner is not `MATNEST` then
2207: `PCFieldSplitSetFields()` is for defining fields as strided blocks (based on the block size provided to the matrix with `MatSetBlockSize()` or
2208: to the `PC` with `PCFieldSplitSetBlockSize()`). For example, if the block
2209: 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
2210: 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x23x56x8.. x12x45x78x....
2211: where the numbered entries indicate what is in the split.
2213: This function is called once per split (it creates a new split each time). Solve options
2214: for this split will be available under the prefix `-fieldsplit_SPLITNAME_`.
2216: `PCFieldSplitSetIS()` does not support having a `fields_col` different from `fields`
2218: Developer Notes:
2219: This routine does not actually create the `IS` representing the split, that is delayed
2220: until `PCSetUp_FieldSplit()`, because information about the vector/matrix layouts may not be
2221: available when this routine is called.
2223: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetIS()`, `PCFieldSplitRestrictIS()`,
2224: `MatSetBlockSize()`, `MatCreateNest()`
2225: @*/
2226: PetscErrorCode PCFieldSplitSetFields(PC pc, const char splitname[], PetscInt n, const PetscInt fields[], const PetscInt fields_col[])
2227: {
2228: PetscFunctionBegin;
2230: PetscAssertPointer(splitname, 2);
2231: PetscCheck(n >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Provided number of fields %" PetscInt_FMT " in split \"%s\" not positive", n, splitname);
2232: PetscAssertPointer(fields, 4);
2233: PetscTryMethod(pc, "PCFieldSplitSetFields_C", (PC, const char[], PetscInt, const PetscInt *, const PetscInt *), (pc, splitname, n, fields, fields_col));
2234: PetscFunctionReturn(PETSC_SUCCESS);
2235: }
2237: /*@
2238: PCFieldSplitSetDiagUseAmat - set flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2239: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2241: Logically Collective
2243: Input Parameters:
2244: + pc - the preconditioner object
2245: - flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2247: Options Database Key:
2248: . -pc_fieldsplit_diag_use_amat - use the Amat to provide the diagonal blocks
2250: Level: intermediate
2252: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetDiagUseAmat()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFIELDSPLIT`
2253: @*/
2254: PetscErrorCode PCFieldSplitSetDiagUseAmat(PC pc, PetscBool flg)
2255: {
2256: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2257: PetscBool isfs;
2259: PetscFunctionBegin;
2261: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2262: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2263: jac->diag_use_amat = flg;
2264: PetscFunctionReturn(PETSC_SUCCESS);
2265: }
2267: /*@
2268: PCFieldSplitGetDiagUseAmat - get the flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2269: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2271: Logically Collective
2273: Input Parameter:
2274: . pc - the preconditioner object
2276: Output Parameter:
2277: . flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2279: Level: intermediate
2281: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetDiagUseAmat()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFIELDSPLIT`
2282: @*/
2283: PetscErrorCode PCFieldSplitGetDiagUseAmat(PC pc, PetscBool *flg)
2284: {
2285: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2286: PetscBool isfs;
2288: PetscFunctionBegin;
2290: PetscAssertPointer(flg, 2);
2291: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2292: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2293: *flg = jac->diag_use_amat;
2294: PetscFunctionReturn(PETSC_SUCCESS);
2295: }
2297: /*@
2298: PCFieldSplitSetOffDiagUseAmat - set flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2299: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2301: Logically Collective
2303: Input Parameters:
2304: + pc - the preconditioner object
2305: - flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2307: Options Database Key:
2308: . -pc_fieldsplit_off_diag_use_amat <bool> - use the Amat to extract the off-diagonal blocks
2310: Level: intermediate
2312: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFieldSplitSetDiagUseAmat()`, `PCFIELDSPLIT`
2313: @*/
2314: PetscErrorCode PCFieldSplitSetOffDiagUseAmat(PC pc, PetscBool flg)
2315: {
2316: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2317: PetscBool isfs;
2319: PetscFunctionBegin;
2321: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2322: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2323: jac->offdiag_use_amat = flg;
2324: PetscFunctionReturn(PETSC_SUCCESS);
2325: }
2327: /*@
2328: PCFieldSplitGetOffDiagUseAmat - get the flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2329: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2331: Logically Collective
2333: Input Parameter:
2334: . pc - the preconditioner object
2336: Output Parameter:
2337: . flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2339: Level: intermediate
2341: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFieldSplitGetDiagUseAmat()`, `PCFIELDSPLIT`
2342: @*/
2343: PetscErrorCode PCFieldSplitGetOffDiagUseAmat(PC pc, PetscBool *flg)
2344: {
2345: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2346: PetscBool isfs;
2348: PetscFunctionBegin;
2350: PetscAssertPointer(flg, 2);
2351: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2352: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2353: *flg = jac->offdiag_use_amat;
2354: PetscFunctionReturn(PETSC_SUCCESS);
2355: }
2357: /*@
2358: PCFieldSplitSetIS - Sets the exact elements for a split in a `PCFIELDSPLIT`
2360: Logically Collective
2362: Input Parameters:
2363: + pc - the preconditioner context
2364: . splitname - name of this split, if `NULL` the number of the split is used
2365: - is - the index set that defines the elements in this split
2367: Level: intermediate
2369: Notes:
2370: Use `PCFieldSplitSetFields()`, for splits defined by strided `IS` based on the matrix block size or the `is_rows[]` passed into `MATNEST`
2372: This function is called once per split (it creates a new split each time). Solve options
2373: for this split will be available under the prefix -fieldsplit_SPLITNAME_.
2375: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetFields()`
2376: @*/
2377: PetscErrorCode PCFieldSplitSetIS(PC pc, const char splitname[], IS is)
2378: {
2379: PetscFunctionBegin;
2381: if (splitname) PetscAssertPointer(splitname, 2);
2383: PetscTryMethod(pc, "PCFieldSplitSetIS_C", (PC, const char[], IS), (pc, splitname, is));
2384: PetscFunctionReturn(PETSC_SUCCESS);
2385: }
2387: /*@
2388: PCFieldSplitGetIS - Retrieves the elements for a split as an `IS`
2390: Logically Collective
2392: Input Parameters:
2393: + pc - the preconditioner context
2394: - splitname - name of this split
2396: Output Parameter:
2397: . is - the index set that defines the elements in this split, or `NULL` if the split is not found
2399: Level: intermediate
2401: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetIS()`, `PCFieldSplitGetISByIndex()`
2402: @*/
2403: PetscErrorCode PCFieldSplitGetIS(PC pc, const char splitname[], IS *is)
2404: {
2405: PetscFunctionBegin;
2407: PetscAssertPointer(splitname, 2);
2408: PetscAssertPointer(is, 3);
2409: {
2410: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2411: PC_FieldSplitLink ilink = jac->head;
2412: PetscBool found;
2414: *is = NULL;
2415: while (ilink) {
2416: PetscCall(PetscStrcmp(ilink->splitname, splitname, &found));
2417: if (found) {
2418: *is = ilink->is;
2419: break;
2420: }
2421: ilink = ilink->next;
2422: }
2423: }
2424: PetscFunctionReturn(PETSC_SUCCESS);
2425: }
2427: /*@
2428: PCFieldSplitGetISByIndex - Retrieves the elements for a given split as an `IS`
2430: Logically Collective
2432: Input Parameters:
2433: + pc - the preconditioner context
2434: - index - index of this split
2436: Output Parameter:
2437: . is - the index set that defines the elements in this split
2439: Level: intermediate
2441: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitGetIS()`, `PCFieldSplitSetIS()`,
2443: @*/
2444: PetscErrorCode PCFieldSplitGetISByIndex(PC pc, PetscInt index, IS *is)
2445: {
2446: PetscFunctionBegin;
2447: PetscCheck(index >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", index);
2449: PetscAssertPointer(is, 3);
2450: {
2451: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2452: PC_FieldSplitLink ilink = jac->head;
2453: PetscInt i = 0;
2454: PetscCheck(index < jac->nsplits, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " requested but only %" PetscInt_FMT " exist", index, jac->nsplits);
2456: while (i < index) {
2457: ilink = ilink->next;
2458: ++i;
2459: }
2460: PetscCall(PCFieldSplitGetIS(pc, ilink->splitname, is));
2461: }
2462: PetscFunctionReturn(PETSC_SUCCESS);
2463: }
2465: /*@
2466: PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the
2467: fieldsplit preconditioner when calling `PCFieldSplitSetFields()`. If not set the matrix block size is used.
2469: Logically Collective
2471: Input Parameters:
2472: + pc - the preconditioner context
2473: - bs - the block size
2475: Level: intermediate
2477: Note:
2478: If the matrix is a `MATNEST` then the `is_rows[]` passed to `MatCreateNest()` determines the fields.
2480: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2481: @*/
2482: PetscErrorCode PCFieldSplitSetBlockSize(PC pc, PetscInt bs)
2483: {
2484: PetscFunctionBegin;
2487: PetscTryMethod(pc, "PCFieldSplitSetBlockSize_C", (PC, PetscInt), (pc, bs));
2488: PetscFunctionReturn(PETSC_SUCCESS);
2489: }
2491: /*@C
2492: PCFieldSplitGetSubKSP - Gets the `KSP` contexts for all splits
2494: Collective
2496: Input Parameter:
2497: . pc - the preconditioner context
2499: Output Parameters:
2500: + n - the number of splits
2501: - subksp - the array of `KSP` contexts
2503: Level: advanced
2505: Notes:
2506: After `PCFieldSplitGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2507: (not the `KSP`, just the array that contains them).
2509: You must call `PCSetUp()` before calling `PCFieldSplitGetSubKSP()`.
2511: If the fieldsplit is of type `PC_COMPOSITE_SCHUR`, it returns the `KSP` object used inside the
2512: Schur complement and the `KSP` object used to iterate over the Schur complement.
2513: To access all the `KSP` objects used in `PC_COMPOSITE_SCHUR`, use `PCFieldSplitSchurGetSubKSP()`.
2515: If the fieldsplit is of type `PC_COMPOSITE_GKB`, it returns the `KSP` object used to solve the
2516: inner linear system defined by the matrix H in each loop.
2518: Fortran Note:
2519: Call `PCFieldSplitRestoreSubKSP()` when the array of `KSP` is no longer needed
2521: Developer Notes:
2522: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2524: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitSchurGetSubKSP()`
2525: @*/
2526: PetscErrorCode PCFieldSplitGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2527: {
2528: PetscFunctionBegin;
2530: if (n) PetscAssertPointer(n, 2);
2531: PetscUseMethod(pc, "PCFieldSplitGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2532: PetscFunctionReturn(PETSC_SUCCESS);
2533: }
2535: /*@C
2536: PCFieldSplitSchurGetSubKSP - Gets the `KSP` contexts used inside the Schur complement based `PCFIELDSPLIT`
2538: Collective
2540: Input Parameter:
2541: . pc - the preconditioner context
2543: Output Parameters:
2544: + n - the number of splits
2545: - subksp - the array of `KSP` contexts
2547: Level: advanced
2549: Notes:
2550: After `PCFieldSplitSchurGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2551: (not the `KSP` just the array that contains them).
2553: You must call `PCSetUp()` before calling `PCFieldSplitSchurGetSubKSP()`.
2555: If the fieldsplit type is of type `PC_COMPOSITE_SCHUR`, it returns (in order)
2556: + 1 - the `KSP` used for the (1,1) block
2557: . 2 - the `KSP` used for the Schur complement (not the one used for the interior Schur solver)
2558: - 3 - the `KSP` used for the (1,1) block in the upper triangular factor (if different from that of the (1,1) block).
2560: It returns a null array if the fieldsplit is not of type `PC_COMPOSITE_SCHUR`; in this case, you should use `PCFieldSplitGetSubKSP()`.
2562: Fortran Note:
2563: Call `PCFieldSplitSchurRestoreSubKSP()` when the array of `KSP` is no longer needed
2565: Developer Notes:
2566: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2568: Should the functionality of `PCFieldSplitSchurGetSubKSP()` and `PCFieldSplitGetSubKSP()` be merged?
2570: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitGetSubKSP()`
2571: @*/
2572: PetscErrorCode PCFieldSplitSchurGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2573: {
2574: PetscFunctionBegin;
2576: if (n) PetscAssertPointer(n, 2);
2577: PetscUseMethod(pc, "PCFieldSplitSchurGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2578: PetscFunctionReturn(PETSC_SUCCESS);
2579: }
2581: /*@
2582: PCFieldSplitSetSchurPre - Indicates from what operator the preconditioner is constructed for the Schur complement.
2583: The default is the A11 matrix.
2585: Collective
2587: Input Parameters:
2588: + pc - the preconditioner context
2589: . ptype - which matrix to use for preconditioning the Schur complement: `PC_FIELDSPLIT_SCHUR_PRE_A11` (default),
2590: `PC_FIELDSPLIT_SCHUR_PRE_SELF`, `PC_FIELDSPLIT_SCHUR_PRE_USER`,
2591: `PC_FIELDSPLIT_SCHUR_PRE_SELFP`, and `PC_FIELDSPLIT_SCHUR_PRE_FULL`
2592: - pre - matrix to use for preconditioning, or `NULL`
2594: Options Database Keys:
2595: + -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is `a11`. See notes for meaning of various arguments
2596: - -fieldsplit_1_pc_type <pctype> - the preconditioner algorithm that is used to construct the preconditioner from the operator
2598: Level: intermediate
2600: Notes:
2601: If ptype is
2602: + a11 - the preconditioner for the Schur complement is generated from the block diagonal part of the preconditioner
2603: matrix associated with the Schur complement (i.e. A11), not the Schur complement matrix
2604: . self - the preconditioner for the Schur complement is generated from the symbolic representation of the Schur complement matrix:
2605: The only preconditioners that currently work with this symbolic representation matrix object are `PCLSC` and `PCHPDDM`
2606: . user - the preconditioner for the Schur complement is generated from the user provided matrix (pre argument
2607: to this function).
2608: . selfp - the preconditioning for the Schur complement is generated from an explicitly-assembled approximation $ Sp = A11 - A10 inv(diag(A00)) A01 $
2609: This is only a good preconditioner when diag(A00) is a good preconditioner for A00. Optionally, A00 can be
2610: lumped before extracting the diagonal using the additional option `-fieldsplit_1_mat_schur_complement_ainv_type lump`
2611: - full - the preconditioner for the Schur complement is generated from the exact Schur complement matrix representation
2612: computed internally by `PCFIELDSPLIT` (this is expensive)
2613: useful mostly as a test that the Schur complement approach can work for your problem
2615: When solving a saddle point problem, where the A11 block is identically zero, using `a11` as the ptype only makes sense
2616: with the additional option `-fieldsplit_1_pc_type none`. Usually for saddle point problems one would use a `ptype` of `self` and
2617: `-fieldsplit_1_pc_type lsc` which uses the least squares commutator to compute a preconditioner for the Schur complement.
2619: Developer Note:
2620: The name of this function and the option `-pc_fieldsplit_schur_precondition` are inconsistent; precondition should be used everywhere.
2622: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`,
2623: `MatSchurComplementSetAinvType()`, `PCLSC`, `PCFieldSplitSetSchurFactType()`
2624: @*/
2625: PetscErrorCode PCFieldSplitSetSchurPre(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2626: {
2627: PetscFunctionBegin;
2629: PetscTryMethod(pc, "PCFieldSplitSetSchurPre_C", (PC, PCFieldSplitSchurPreType, Mat), (pc, ptype, pre));
2630: PetscFunctionReturn(PETSC_SUCCESS);
2631: }
2633: PetscErrorCode PCFieldSplitSchurPrecondition(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2634: {
2635: return PCFieldSplitSetSchurPre(pc, ptype, pre);
2636: } /* Deprecated name */
2638: /*@
2639: PCFieldSplitGetSchurPre - For Schur complement fieldsplit, determine how the Schur complement will be
2640: preconditioned. See `PCFieldSplitSetSchurPre()` for details.
2642: Logically Collective
2644: Input Parameter:
2645: . pc - the preconditioner context
2647: Output Parameters:
2648: + 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`
2649: - pre - matrix to use for preconditioning (with `PC_FIELDSPLIT_SCHUR_PRE_USER`), or `NULL`
2651: Level: intermediate
2653: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCLSC`
2654: @*/
2655: PetscErrorCode PCFieldSplitGetSchurPre(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2656: {
2657: PetscFunctionBegin;
2659: PetscUseMethod(pc, "PCFieldSplitGetSchurPre_C", (PC, PCFieldSplitSchurPreType *, Mat *), (pc, ptype, pre));
2660: PetscFunctionReturn(PETSC_SUCCESS);
2661: }
2663: /*@
2664: PCFieldSplitSchurGetS - extract the `MATSCHURCOMPLEMENT` object used by this `PCFIELDSPLIT` in case it needs to be configured separately
2666: Not Collective
2668: Input Parameter:
2669: . pc - the preconditioner context
2671: Output Parameter:
2672: . S - the Schur complement matrix
2674: Level: advanced
2676: Note:
2677: This matrix should not be destroyed using `MatDestroy()`; rather, use `PCFieldSplitSchurRestoreS()`.
2679: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MATSCHURCOMPLEMENT`, `PCFieldSplitSchurRestoreS()`,
2680: `MatCreateSchurComplement()`, `MatSchurComplementGetKSP()`, `MatSchurComplementComputeExplicitOperator()`, `MatGetSchurComplement()`
2681: @*/
2682: PetscErrorCode PCFieldSplitSchurGetS(PC pc, Mat *S)
2683: {
2684: const char *t;
2685: PetscBool isfs;
2686: PC_FieldSplit *jac;
2688: PetscFunctionBegin;
2690: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2691: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2692: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2693: jac = (PC_FieldSplit *)pc->data;
2694: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2695: if (S) *S = jac->schur;
2696: PetscFunctionReturn(PETSC_SUCCESS);
2697: }
2699: /*@
2700: PCFieldSplitSchurRestoreS - returns the `MATSCHURCOMPLEMENT` matrix used by this `PC`
2702: Not Collective
2704: Input Parameters:
2705: + pc - the preconditioner context
2706: - S - the Schur complement matrix
2708: Level: advanced
2710: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MatSchurComplement`, `PCFieldSplitSchurGetS()`
2711: @*/
2712: PetscErrorCode PCFieldSplitSchurRestoreS(PC pc, Mat *S)
2713: {
2714: const char *t;
2715: PetscBool isfs;
2716: PC_FieldSplit *jac;
2718: PetscFunctionBegin;
2720: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2721: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2722: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2723: jac = (PC_FieldSplit *)pc->data;
2724: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2725: PetscCheck(S && (*S == jac->schur), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MatSchurComplement restored is not the same as gotten");
2726: PetscFunctionReturn(PETSC_SUCCESS);
2727: }
2729: static PetscErrorCode PCFieldSplitSetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2730: {
2731: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2733: PetscFunctionBegin;
2734: jac->schurpre = ptype;
2735: if (ptype == PC_FIELDSPLIT_SCHUR_PRE_USER && pre) {
2736: PetscCall(MatDestroy(&jac->schur_user));
2737: jac->schur_user = pre;
2738: PetscCall(PetscObjectReference((PetscObject)jac->schur_user));
2739: }
2740: PetscFunctionReturn(PETSC_SUCCESS);
2741: }
2743: static PetscErrorCode PCFieldSplitGetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2744: {
2745: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2747: PetscFunctionBegin;
2748: if (ptype) *ptype = jac->schurpre;
2749: if (pre) *pre = jac->schur_user;
2750: PetscFunctionReturn(PETSC_SUCCESS);
2751: }
2753: /*@
2754: PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain in the preconditioner {cite}`murphy2000note` and {cite}`ipsen2001note`
2756: Collective
2758: Input Parameters:
2759: + pc - the preconditioner context
2760: - ftype - which blocks of factorization to retain, `PC_FIELDSPLIT_SCHUR_FACT_FULL` is default
2762: Options Database Key:
2763: . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> - default is `full`
2765: Level: intermediate
2767: Notes:
2768: The `full` factorization is
2770: ```{math}
2771: \left(\begin{array}{cc} A & B \\
2772: C & E \\
2773: \end{array}\right) =
2774: \left(\begin{array}{cc} I & 0 \\
2775: C A^{-1} & I \\
2776: \end{array}\right)
2777: \left(\begin{array}{cc} A & 0 \\
2778: 0 & S \\
2779: \end{array}\right)
2780: \left(\begin{array}{cc} I & A^{-1}B \\
2781: 0 & I \\
2782: \end{array}\right) = L D U,
2783: ```
2785: where $ S = E - C A^{-1} B $. In practice, the full factorization is applied via block triangular solves with the grouping $L(DU)$. `upper` uses $DU$, `lower` uses $LD$,
2786: and `diag` is the diagonal part with the sign of $S$ flipped (because this makes the preconditioner positive definite for many formulations,
2787: thus allowing the use of `KSPMINRES)`. Sign flipping of $S$ can be turned off with `PCFieldSplitSetSchurScale()`.
2789: If $A$ and $S$ are solved exactly
2790: + 1 - `full` factorization is a direct solver.
2791: . 2 - 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.
2792: - 3 - 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.
2794: If the iteration count is very low, consider using `KSPFGMRES` or `KSPGCR` which can use one less preconditioner
2795: application in this case. Note that the preconditioned operator may be highly non-normal, so such fast convergence may not be observed in practice.
2797: For symmetric problems in which $A$ is positive definite and $S$ is negative definite, `diag` can be used with `KSPMINRES`.
2799: 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 $S$).
2801: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurScale()`,
2802: [](sec_flexibleksp), `PCFieldSplitSetSchurPre()`
2803: @*/
2804: PetscErrorCode PCFieldSplitSetSchurFactType(PC pc, PCFieldSplitSchurFactType ftype)
2805: {
2806: PetscFunctionBegin;
2808: PetscTryMethod(pc, "PCFieldSplitSetSchurFactType_C", (PC, PCFieldSplitSchurFactType), (pc, ftype));
2809: PetscFunctionReturn(PETSC_SUCCESS);
2810: }
2812: static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc, PCFieldSplitSchurFactType ftype)
2813: {
2814: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2816: PetscFunctionBegin;
2817: jac->schurfactorization = ftype;
2818: PetscFunctionReturn(PETSC_SUCCESS);
2819: }
2821: /*@
2822: PCFieldSplitSetSchurScale - Controls the sign flip of S for `PC_FIELDSPLIT_SCHUR_FACT_DIAG`.
2824: Collective
2826: Input Parameters:
2827: + pc - the preconditioner context
2828: - scale - scaling factor for the Schur complement
2830: Options Database Key:
2831: . -pc_fieldsplit_schur_scale <scale> - default is -1.0
2833: Level: intermediate
2835: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurFactType`, `PCFieldSplitSetSchurFactType()`
2836: @*/
2837: PetscErrorCode PCFieldSplitSetSchurScale(PC pc, PetscScalar scale)
2838: {
2839: PetscFunctionBegin;
2842: PetscTryMethod(pc, "PCFieldSplitSetSchurScale_C", (PC, PetscScalar), (pc, scale));
2843: PetscFunctionReturn(PETSC_SUCCESS);
2844: }
2846: static PetscErrorCode PCFieldSplitSetSchurScale_FieldSplit(PC pc, PetscScalar scale)
2847: {
2848: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2850: PetscFunctionBegin;
2851: jac->schurscale = scale;
2852: PetscFunctionReturn(PETSC_SUCCESS);
2853: }
2855: /*@C
2856: PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement
2858: Collective
2860: Input Parameter:
2861: . pc - the preconditioner context
2863: Output Parameters:
2864: + A00 - the (0,0) block
2865: . A01 - the (0,1) block
2866: . A10 - the (1,0) block
2867: - A11 - the (1,1) block
2869: Level: advanced
2871: Note:
2872: Use `NULL` for any unneeded output arguments
2874: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `MatSchurComplementGetSubMatrices()`, `MatSchurComplementSetSubMatrices()`
2875: @*/
2876: PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc, Mat *A00, Mat *A01, Mat *A10, Mat *A11)
2877: {
2878: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2880: PetscFunctionBegin;
2882: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach.");
2883: if (A00) *A00 = jac->pmat[0];
2884: if (A01) *A01 = jac->B;
2885: if (A10) *A10 = jac->C;
2886: if (A11) *A11 = jac->pmat[1];
2887: PetscFunctionReturn(PETSC_SUCCESS);
2888: }
2890: /*@
2891: PCFieldSplitSetGKBTol - Sets the solver tolerance for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
2893: Collective
2895: Input Parameters:
2896: + pc - the preconditioner context
2897: - tolerance - the solver tolerance
2899: Options Database Key:
2900: . -pc_fieldsplit_gkb_tol <tolerance> - default is 1e-5
2902: Level: intermediate
2904: Note:
2905: The generalized GKB algorithm {cite}`arioli2013` uses a lower bound estimate of the error in energy norm as stopping criterion.
2906: It stops once the lower bound estimate undershoots the required solver tolerance. Although the actual error might be bigger than
2907: this estimate, the stopping criterion is satisfactory in practical cases.
2909: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBMaxit()`
2910: @*/
2911: PetscErrorCode PCFieldSplitSetGKBTol(PC pc, PetscReal tolerance)
2912: {
2913: PetscFunctionBegin;
2916: PetscTryMethod(pc, "PCFieldSplitSetGKBTol_C", (PC, PetscReal), (pc, tolerance));
2917: PetscFunctionReturn(PETSC_SUCCESS);
2918: }
2920: static PetscErrorCode PCFieldSplitSetGKBTol_FieldSplit(PC pc, PetscReal tolerance)
2921: {
2922: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2924: PetscFunctionBegin;
2925: jac->gkbtol = tolerance;
2926: PetscFunctionReturn(PETSC_SUCCESS);
2927: }
2929: /*@
2930: PCFieldSplitSetGKBMaxit - Sets the maximum number of iterations for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
2932: Collective
2934: Input Parameters:
2935: + pc - the preconditioner context
2936: - maxit - the maximum number of iterations
2938: Options Database Key:
2939: . -pc_fieldsplit_gkb_maxit <maxit> - default is 100
2941: Level: intermediate
2943: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBNu()`
2944: @*/
2945: PetscErrorCode PCFieldSplitSetGKBMaxit(PC pc, PetscInt maxit)
2946: {
2947: PetscFunctionBegin;
2950: PetscTryMethod(pc, "PCFieldSplitSetGKBMaxit_C", (PC, PetscInt), (pc, maxit));
2951: PetscFunctionReturn(PETSC_SUCCESS);
2952: }
2954: static PetscErrorCode PCFieldSplitSetGKBMaxit_FieldSplit(PC pc, PetscInt maxit)
2955: {
2956: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2958: PetscFunctionBegin;
2959: jac->gkbmaxit = maxit;
2960: PetscFunctionReturn(PETSC_SUCCESS);
2961: }
2963: /*@
2964: PCFieldSplitSetGKBDelay - Sets the delay in the lower bound error estimate in the generalized Golub-Kahan bidiagonalization {cite}`arioli2013` in `PCFIELDSPLIT`
2965: preconditioner.
2967: Collective
2969: Input Parameters:
2970: + pc - the preconditioner context
2971: - delay - the delay window in the lower bound estimate
2973: Options Database Key:
2974: . -pc_fieldsplit_gkb_delay <delay> - default is 5
2976: Level: intermediate
2978: Notes:
2979: 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 $
2980: is expressed as a truncated sum. The error at iteration k can only be measured at iteration (k + `delay`), and thus the algorithm needs
2981: at least (`delay` + 1) iterations to stop.
2983: For more details on the generalized Golub-Kahan bidiagonalization method and its lower bound stopping criterion, please refer to {cite}`arioli2013`
2985: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
2986: @*/
2987: PetscErrorCode PCFieldSplitSetGKBDelay(PC pc, PetscInt delay)
2988: {
2989: PetscFunctionBegin;
2992: PetscTryMethod(pc, "PCFieldSplitSetGKBDelay_C", (PC, PetscInt), (pc, delay));
2993: PetscFunctionReturn(PETSC_SUCCESS);
2994: }
2996: static PetscErrorCode PCFieldSplitSetGKBDelay_FieldSplit(PC pc, PetscInt delay)
2997: {
2998: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3000: PetscFunctionBegin;
3001: jac->gkbdelay = delay;
3002: PetscFunctionReturn(PETSC_SUCCESS);
3003: }
3005: /*@
3006: PCFieldSplitSetGKBNu - Sets the scalar value nu >= 0 in the transformation H = A00 + nu*A01*A01' of the (1,1) block in the
3007: Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
3009: Collective
3011: Input Parameters:
3012: + pc - the preconditioner context
3013: - nu - the shift parameter
3015: Options Database Key:
3016: . -pc_fieldsplit_gkb_nu <nu> - default is 1
3018: Level: intermediate
3020: Notes:
3021: 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,
3022: 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
3023: necessary to find a good balance in between the convergence of the inner and outer loop.
3025: 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.
3027: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
3028: @*/
3029: PetscErrorCode PCFieldSplitSetGKBNu(PC pc, PetscReal nu)
3030: {
3031: PetscFunctionBegin;
3034: PetscTryMethod(pc, "PCFieldSplitSetGKBNu_C", (PC, PetscReal), (pc, nu));
3035: PetscFunctionReturn(PETSC_SUCCESS);
3036: }
3038: static PetscErrorCode PCFieldSplitSetGKBNu_FieldSplit(PC pc, PetscReal nu)
3039: {
3040: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3042: PetscFunctionBegin;
3043: jac->gkbnu = nu;
3044: PetscFunctionReturn(PETSC_SUCCESS);
3045: }
3047: static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc, PCCompositeType type)
3048: {
3049: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3051: PetscFunctionBegin;
3052: jac->type = type;
3053: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
3054: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
3055: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
3056: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
3057: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
3058: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
3059: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
3060: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
3061: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
3063: if (type == PC_COMPOSITE_SCHUR) {
3064: pc->ops->apply = PCApply_FieldSplit_Schur;
3065: pc->ops->applytranspose = PCApplyTranspose_FieldSplit_Schur;
3066: pc->ops->view = PCView_FieldSplit_Schur;
3067: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_Schur;
3069: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit_Schur));
3070: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", PCFieldSplitSetSchurPre_FieldSplit));
3071: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", PCFieldSplitGetSchurPre_FieldSplit));
3072: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", PCFieldSplitSetSchurFactType_FieldSplit));
3073: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", PCFieldSplitSetSchurScale_FieldSplit));
3074: } else if (type == PC_COMPOSITE_GKB) {
3075: pc->ops->apply = PCApply_FieldSplit_GKB;
3076: pc->ops->applytranspose = NULL;
3077: pc->ops->view = PCView_FieldSplit_GKB;
3078: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_GKB;
3080: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3081: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", PCFieldSplitSetGKBTol_FieldSplit));
3082: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", PCFieldSplitSetGKBMaxit_FieldSplit));
3083: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", PCFieldSplitSetGKBNu_FieldSplit));
3084: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", PCFieldSplitSetGKBDelay_FieldSplit));
3085: } else {
3086: pc->ops->apply = PCApply_FieldSplit;
3087: pc->ops->applytranspose = PCApplyTranspose_FieldSplit;
3088: pc->ops->view = PCView_FieldSplit;
3089: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit;
3091: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3092: }
3093: PetscFunctionReturn(PETSC_SUCCESS);
3094: }
3096: static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc, PetscInt bs)
3097: {
3098: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3100: PetscFunctionBegin;
3101: PetscCheck(bs >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Blocksize must be positive, you gave %" PetscInt_FMT, bs);
3102: 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);
3103: jac->bs = bs;
3104: PetscFunctionReturn(PETSC_SUCCESS);
3105: }
3107: static PetscErrorCode PCSetCoordinates_FieldSplit(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[])
3108: {
3109: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3110: PC_FieldSplitLink ilink_current = jac->head;
3111: IS is_owned;
3113: PetscFunctionBegin;
3114: jac->coordinates_set = PETSC_TRUE; // Internal flag
3115: PetscCall(MatGetOwnershipIS(pc->mat, &is_owned, NULL));
3117: while (ilink_current) {
3118: // For each IS, embed it to get local coords indces
3119: IS is_coords;
3120: PetscInt ndofs_block;
3121: const PetscInt *block_dofs_enumeration; // Numbering of the dofs relevant to the current block
3123: // Setting drop to true for safety. It should make no difference.
3124: PetscCall(ISEmbed(ilink_current->is, is_owned, PETSC_TRUE, &is_coords));
3125: PetscCall(ISGetLocalSize(is_coords, &ndofs_block));
3126: PetscCall(ISGetIndices(is_coords, &block_dofs_enumeration));
3128: // Allocate coordinates vector and set it directly
3129: PetscCall(PetscMalloc1(ndofs_block * dim, &ilink_current->coords));
3130: for (PetscInt dof = 0; dof < ndofs_block; ++dof) {
3131: for (PetscInt d = 0; d < dim; ++d) (ilink_current->coords)[dim * dof + d] = coords[dim * block_dofs_enumeration[dof] + d];
3132: }
3133: ilink_current->dim = dim;
3134: ilink_current->ndofs = ndofs_block;
3135: PetscCall(ISRestoreIndices(is_coords, &block_dofs_enumeration));
3136: PetscCall(ISDestroy(&is_coords));
3137: ilink_current = ilink_current->next;
3138: }
3139: PetscCall(ISDestroy(&is_owned));
3140: PetscFunctionReturn(PETSC_SUCCESS);
3141: }
3143: /*@
3144: PCFieldSplitSetType - Sets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3146: Collective
3148: Input Parameters:
3149: + pc - the preconditioner context
3150: - type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`,
3151: `PC_COMPOSITE_GKB`
3153: Options Database Key:
3154: . -pc_fieldsplit_type <one of multiplicative, additive, symmetric_multiplicative, special, schur> - Sets fieldsplit preconditioner type
3156: Level: intermediate
3158: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCCompositeType`, `PCCompositeGetType()`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3159: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`, `PCFieldSplitSetSchurFactType()`
3160: @*/
3161: PetscErrorCode PCFieldSplitSetType(PC pc, PCCompositeType type)
3162: {
3163: PetscFunctionBegin;
3165: PetscTryMethod(pc, "PCFieldSplitSetType_C", (PC, PCCompositeType), (pc, type));
3166: PetscFunctionReturn(PETSC_SUCCESS);
3167: }
3169: /*@
3170: PCFieldSplitGetType - Gets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3172: Not collective
3174: Input Parameter:
3175: . pc - the preconditioner context
3177: Output Parameter:
3178: . type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3180: Level: intermediate
3182: .seealso: [](sec_block_matrices), `PC`, `PCCompositeSetType()`, `PCFIELDSPLIT`, `PCCompositeType`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3183: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3184: @*/
3185: PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type)
3186: {
3187: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3189: PetscFunctionBegin;
3191: PetscAssertPointer(type, 2);
3192: *type = jac->type;
3193: PetscFunctionReturn(PETSC_SUCCESS);
3194: }
3196: /*@
3197: PCFieldSplitSetDMSplits - Flags whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3199: Logically Collective
3201: Input Parameters:
3202: + pc - the preconditioner context
3203: - flg - boolean indicating whether to use field splits defined by the `DM`
3205: Options Database Key:
3206: . -pc_fieldsplit_dm_splits <bool> - use the field splits defined by the `DM`
3208: Level: intermediate
3210: Developer Note:
3211: The name should be `PCFieldSplitSetUseDMSplits()`, similar change to options database
3213: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3214: @*/
3215: PetscErrorCode PCFieldSplitSetDMSplits(PC pc, PetscBool flg)
3216: {
3217: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3218: PetscBool isfs;
3220: PetscFunctionBegin;
3223: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3224: if (isfs) jac->dm_splits = flg;
3225: PetscFunctionReturn(PETSC_SUCCESS);
3226: }
3228: /*@
3229: PCFieldSplitGetDMSplits - Returns flag indicating whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3231: Logically Collective
3233: Input Parameter:
3234: . pc - the preconditioner context
3236: Output Parameter:
3237: . flg - boolean indicating whether to use field splits defined by the `DM`
3239: Level: intermediate
3241: Developer Note:
3242: The name should be `PCFieldSplitGetUseDMSplits()`
3244: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3245: @*/
3246: PetscErrorCode PCFieldSplitGetDMSplits(PC pc, PetscBool *flg)
3247: {
3248: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3249: PetscBool isfs;
3251: PetscFunctionBegin;
3253: PetscAssertPointer(flg, 2);
3254: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3255: if (isfs) {
3256: if (flg) *flg = jac->dm_splits;
3257: }
3258: PetscFunctionReturn(PETSC_SUCCESS);
3259: }
3261: /*@
3262: PCFieldSplitGetDetectSaddlePoint - Returns flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3264: Logically Collective
3266: Input Parameter:
3267: . pc - the preconditioner context
3269: Output Parameter:
3270: . flg - boolean indicating whether to detect fields or not
3272: Level: intermediate
3274: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDetectSaddlePoint()`
3275: @*/
3276: PetscErrorCode PCFieldSplitGetDetectSaddlePoint(PC pc, PetscBool *flg)
3277: {
3278: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3280: PetscFunctionBegin;
3281: *flg = jac->detect;
3282: PetscFunctionReturn(PETSC_SUCCESS);
3283: }
3285: /*@
3286: PCFieldSplitSetDetectSaddlePoint - Sets flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3288: Logically Collective
3290: Input Parameter:
3291: . pc - the preconditioner context
3293: Output Parameter:
3294: . flg - boolean indicating whether to detect fields or not
3296: Options Database Key:
3297: . -pc_fieldsplit_detect_saddle_point <bool> - detect and use the saddle point
3299: Level: intermediate
3301: Note:
3302: Also sets the split type to `PC_COMPOSITE_SCHUR` (see `PCFieldSplitSetType()`) and the Schur preconditioner type to `PC_FIELDSPLIT_SCHUR_PRE_SELF` (see `PCFieldSplitSetSchurPre()`).
3304: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDetectSaddlePoint()`, `PCFieldSplitSetType()`, `PCFieldSplitSetSchurPre()`, `PC_FIELDSPLIT_SCHUR_PRE_SELF`
3305: @*/
3306: PetscErrorCode PCFieldSplitSetDetectSaddlePoint(PC pc, PetscBool flg)
3307: {
3308: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3310: PetscFunctionBegin;
3311: jac->detect = flg;
3312: if (jac->detect) {
3313: PetscCall(PCFieldSplitSetType(pc, PC_COMPOSITE_SCHUR));
3314: PetscCall(PCFieldSplitSetSchurPre(pc, PC_FIELDSPLIT_SCHUR_PRE_SELF, NULL));
3315: }
3316: PetscFunctionReturn(PETSC_SUCCESS);
3317: }
3319: /*MC
3320: PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual
3321: collections of variables (that may overlap) called fields or splits. Each field often represents a different continuum variable
3322: represented on a grid, such as velocity, pressure, or temperature.
3323: In the literature these are sometimes called block preconditioners; but should not be confused with `PCBJACOBI`.
3324: See [the users manual section on "Solving Block Matrices"](sec_block_matrices) for more details.
3326: Options Database Keys:
3327: + -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the `%d`'th split
3328: . -pc_fieldsplit_default - automatically add any fields to additional splits that have not
3329: been supplied explicitly by `-pc_fieldsplit_%d_fields`
3330: . -pc_fieldsplit_block_size <bs> - size of block that defines fields (i.e. there are bs fields)
3331: when the matrix is not of `MatType` `MATNEST`
3332: . -pc_fieldsplit_type <additive,multiplicative,symmetric_multiplicative,schur,gkb> - type of relaxation or factorization splitting
3333: . -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is `a11`; see `PCFieldSplitSetSchurPre()`
3334: . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> - set factorization type when using `-pc_fieldsplit_type schur`;
3335: see `PCFieldSplitSetSchurFactType()`
3336: . -pc_fieldsplit_dm_splits <true,false> (default is true) - Whether to use `DMCreateFieldDecomposition()` for splits
3337: - -pc_fieldsplit_detect_saddle_point - automatically finds rows with zero diagonal and uses Schur complement with no preconditioner as the solver
3339: Options prefixes for inner solvers when using the Schur complement preconditioner are `-fieldsplit_0_` and `-fieldsplit_1_` .
3340: The options prefix for the inner solver when using the Golub-Kahan biadiagonalization preconditioner is `-fieldsplit_0_`
3341: For all other solvers they are `-fieldsplit_%d_` for the `%d`'th field; use `-fieldsplit_` for all fields.
3343: To set options on the solvers for all blocks, prepend `-fieldsplit_` to all the `PC`
3344: options database keys. For example, `-fieldsplit_pc_type ilu` `-fieldsplit_pc_factor_levels 1`.
3346: To set the options on the solvers separate for each block call `PCFieldSplitGetSubKSP()`
3347: and set the options directly on the resulting `KSP` object
3349: Level: intermediate
3351: Notes:
3352: Use `PCFieldSplitSetFields()` to set splits defined by "strided" entries or with a `MATNEST` and `PCFieldSplitSetIS()`
3353: to define a split by an arbitrary collection of entries.
3355: If no splits are set, the default is used. If a `DM` is associated with the `PC` and it supports
3356: `DMCreateFieldDecomposition()`, then that is used for the default. Otherwise if the matrix is not `MATNEST`, the splits are defined by entries strided by bs,
3357: beginning at 0 then 1, etc to bs-1. The block size can be set with `PCFieldSplitSetBlockSize()`,
3358: if this is not called the block size defaults to the blocksize of the second matrix passed
3359: to `KSPSetOperators()`/`PCSetOperators()`.
3361: For the Schur complement preconditioner if
3362: ```{math}
3363: J = \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{10} & A_{11} \end{array}\right]
3364: ```
3366: the preconditioner using `full` factorization is logically
3367: ```{math}
3368: \left[\begin{array}{cc} I & -\text{ksp}(A_{00}) A_{01} \\ 0 & I \end{array}\right] \left[\begin{array}{cc} \text{ksp}(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]
3369: ```
3370: where the action of $\text{ksp}(A_{00})$ is applied using the `KSP` solver with prefix `-fieldsplit_0_`. $S$ is the Schur complement
3371: ```{math}
3372: S = A_{11} - A_{10} \text{ksp}(A_{00}) A_{01}
3373: ```
3374: 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`
3375: was given in providing the SECOND split or 1 if not given). Accordingly, if using `PCFieldSplitGetSubKSP()`, the array of sub-`KSP` contexts will hold two `KSP`s: at its
3376: 0th index, the `KSP` associated with `-fieldsplit_0_`, and at its 1st index, the `KSP` corresponding to `-fieldsplit_1_`.
3377: By default, $A_{11}$ is used to construct a preconditioner for $S$, use `PCFieldSplitSetSchurPre()` for all the possible ways to construct the preconditioner for $S$.
3379: The factorization type is set using `-pc_fieldsplit_schur_fact_type <diag, lower, upper, full>`. `full` is shown above,
3380: `diag` gives
3381: ```{math}
3382: \left[\begin{array}{cc} \text{ksp}(A_{00}) & 0 \\ 0 & -\text{ksp}(S) \end{array}\right]
3383: ```
3384: 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
3385: can be turned off with `PCFieldSplitSetSchurScale()` or by command line `-pc_fieldsplit_schur_scale 1.0`. The `lower` factorization is the inverse of
3386: ```{math}
3387: \left[\begin{array}{cc} A_{00} & 0 \\ A_{10} & S \end{array}\right]
3388: ```
3389: where the inverses of $A_{00}$ and $S$ are applied using `KSP`s. The upper factorization is the inverse of
3390: ```{math}
3391: \left[\begin{array}{cc} A_{00} & A_{01} \\ 0 & S \end{array}\right]
3392: ```
3393: where again the inverses of $A_{00}$ and $S$ are applied using `KSP`s.
3395: If only one set of indices (one `IS`) is provided with `PCFieldSplitSetIS()` then the complement of that `IS`
3396: is used automatically for a second submatrix.
3398: The fieldsplit preconditioner cannot currently be used with the `MATBAIJ` or `MATSBAIJ` data formats if the blocksize is larger than 1.
3399: Generally it should be used with the `MATAIJ` or `MATNEST` `MatType`
3401: The forms of these preconditioners are closely related, if not identical, to forms derived as "Distributive Iterations", see,
3402: for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling {cite}`wesseling2009`.
3403: One can also use `PCFIELDSPLIT` inside a smoother resulting in "Distributive Smoothers".
3405: See "A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations" {cite}`elman2008tcp`.
3407: The Constrained Pressure Preconditioner (CPR) can be implemented using `PCCOMPOSITE` with `PCGALERKIN`. CPR first solves an $R A P$ subsystem, updates the
3408: residual on all variables (`PCCompositeSetType(pc,PC_COMPOSITE_MULTIPLICATIVE)`), and then applies a simple ILU like preconditioner on all the variables.
3410: The generalized Golub-Kahan bidiagonalization preconditioner (GKB) can be applied to symmetric $2 \times 2$ block matrices of the shape
3411: ```{math}
3412: \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{01}' & 0 \end{array}\right]
3413: ```
3414: 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 $H = _{A00} + \nu*A_{01}*A_{01}'$.
3415: 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_`.
3417: Some `PCFIELDSPLIT` variants are called physics-based preconditioners, since the preconditioner takes into account the underlying physics of the
3418: problem. But this nomenclature is not well-defined.
3420: Developer Note:
3421: The Schur complement functionality of `PCFIELDSPLIT` should likely be factored into its own `PC` thus simplifying the implementation of the preconditioners and their
3422: user API.
3424: .seealso: [](sec_block_matrices), `PC`, `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCLSC`,
3425: `PCFieldSplitGetSubKSP()`, `PCFieldSplitSchurGetSubKSP()`, `PCFieldSplitSetFields()`,
3426: `PCFieldSplitSetType()`, `PCFieldSplitSetIS()`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitSetSchurFactType()`,
3427: `MatSchurComplementSetAinvType()`, `PCFieldSplitSetSchurScale()`, `PCFieldSplitSetDetectSaddlePoint()`
3428: M*/
3430: PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc)
3431: {
3432: PC_FieldSplit *jac;
3434: PetscFunctionBegin;
3435: PetscCall(PetscNew(&jac));
3437: jac->bs = -1;
3438: jac->type = PC_COMPOSITE_MULTIPLICATIVE;
3439: jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */
3440: jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL;
3441: jac->schurscale = -1.0;
3442: jac->dm_splits = PETSC_TRUE;
3443: jac->gkbtol = 1e-5;
3444: jac->gkbdelay = 5;
3445: jac->gkbnu = 1;
3446: jac->gkbmaxit = 100;
3448: pc->data = (void *)jac;
3450: pc->ops->setup = PCSetUp_FieldSplit;
3451: pc->ops->reset = PCReset_FieldSplit;
3452: pc->ops->destroy = PCDestroy_FieldSplit;
3453: pc->ops->setfromoptions = PCSetFromOptions_FieldSplit;
3454: pc->ops->applyrichardson = NULL;
3456: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", PCFieldSplitSchurGetSubKSP_FieldSplit));
3457: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", PCFieldSplitSetFields_FieldSplit));
3458: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", PCFieldSplitSetIS_FieldSplit));
3459: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", PCFieldSplitSetType_FieldSplit));
3460: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", PCFieldSplitSetBlockSize_FieldSplit));
3461: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", PCFieldSplitRestrictIS_FieldSplit));
3462: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", PCSetCoordinates_FieldSplit));
3464: /* Initialize function pointers */
3465: PetscCall(PCFieldSplitSetType(pc, jac->type));
3466: PetscFunctionReturn(PETSC_SUCCESS);
3467: }