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 sorted, sorted_col, 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(ISDuplicate(ilink->is, &ilink->is_col));
617: } else if (!ilink->is) {
618: if (ilink->nfields > 1) {
619: PetscInt *ii, *jj, j, k, nfields = ilink->nfields, *fields = ilink->fields, *fields_col = ilink->fields_col;
621: PetscCall(PetscMalloc1(ilink->nfields * nslots, &ii));
622: PetscCall(PetscMalloc1(ilink->nfields * nslots, &jj));
623: for (j = 0; j < nslots; j++) {
624: for (k = 0; k < nfields; k++) {
625: ii[nfields * j + k] = rstart + bs * j + fields[k];
626: jj[nfields * j + k] = rstart + bs * j + fields_col[k];
627: }
628: }
629: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, ii, PETSC_OWN_POINTER, &ilink->is));
630: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, jj, PETSC_OWN_POINTER, &ilink->is_col));
631: PetscCall(ISSetBlockSize(ilink->is, nfields));
632: PetscCall(ISSetBlockSize(ilink->is_col, nfields));
633: } else {
634: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields[0], bs, &ilink->is));
635: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields_col[0], bs, &ilink->is_col));
636: }
637: }
638: PetscCall(ISSorted(ilink->is, &sorted));
639: if (ilink->is_col) PetscCall(ISSorted(ilink->is_col, &sorted_col));
640: PetscCheck(sorted && sorted_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Fields must be sorted when creating split");
641: ilink = ilink->next;
642: }
643: } else { /* use the IS that define the MATNEST to determine the index sets that define the submatrices */
644: IS *rowis, *colis, *ises = NULL;
645: PetscInt mis, nis;
647: PetscCall(MatNestGetSize(pc->pmat, &mis, &nis));
648: PetscCall(PetscMalloc2(mis, &rowis, nis, &colis));
649: PetscCall(MatNestGetISs(pc->pmat, rowis, colis));
650: if (!jac->defaultsplit) PetscCall(PetscMalloc1(mis, &ises));
652: for (i = 0; i < nsplit; i++) {
653: if (jac->defaultsplit) {
654: PetscCall(ISDuplicate(rowis[i], &ilink->is));
655: PetscCall(ISDuplicate(ilink->is, &ilink->is_col));
656: } else if (!ilink->is) {
657: if (ilink->nfields > 1) {
658: for (PetscInt j = 0; j < ilink->nfields; j++) ises[j] = rowis[ilink->fields[j]];
659: PetscCall(ISConcatenate(PetscObjectComm((PetscObject)pc), ilink->nfields, ises, &ilink->is));
660: } else {
661: PetscCall(ISDuplicate(rowis[ilink->fields[0]], &ilink->is));
662: }
663: PetscCall(ISDuplicate(ilink->is, &ilink->is_col));
664: }
665: ilink = ilink->next;
666: }
667: PetscCall(PetscFree2(rowis, colis));
668: PetscCall(PetscFree(ises));
669: }
670: }
672: ilink = jac->head;
673: if (!jac->pmat) {
674: Vec xtmp;
676: PetscCall(MatCreateVecs(pc->pmat, &xtmp, NULL));
677: PetscCall(PetscMalloc1(nsplit, &jac->pmat));
678: PetscCall(PetscMalloc2(nsplit, &jac->x, nsplit, &jac->y));
679: for (i = 0; i < nsplit; i++) {
680: MatNullSpace sp;
682: /* Check for matrix attached to IS */
683: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&jac->pmat[i]));
684: if (jac->pmat[i]) {
685: PetscCall(PetscObjectReference((PetscObject)jac->pmat[i]));
686: if (jac->type == PC_COMPOSITE_SCHUR) {
687: jac->schur_user = jac->pmat[i];
689: PetscCall(PetscObjectReference((PetscObject)jac->schur_user));
690: }
691: } else {
692: const char *prefix;
693: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->pmat[i]));
694: PetscCall(MatGetOptionsPrefix(jac->pmat[i], &prefix));
695: if (!prefix) {
696: PetscCall(KSPGetOptionsPrefix(ilink->ksp, &prefix));
697: PetscCall(MatSetOptionsPrefix(jac->pmat[i], prefix));
698: }
699: PetscCall(MatSetFromOptions(jac->pmat[i]));
700: PetscCall(MatViewFromOptions(jac->pmat[i], NULL, "-mat_view"));
701: }
702: /* create work vectors for each split */
703: PetscCall(MatCreateVecs(jac->pmat[i], &jac->x[i], &jac->y[i]));
704: ilink->x = jac->x[i];
705: ilink->y = jac->y[i];
706: ilink->z = NULL;
707: /* compute scatter contexts needed by multiplicative versions and non-default splits */
708: PetscCall(VecScatterCreate(xtmp, ilink->is, jac->x[i], NULL, &ilink->sctx));
709: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nearnullspace", (PetscObject *)&sp));
710: if (sp) PetscCall(MatSetNearNullSpace(jac->pmat[i], sp));
711: ilink = ilink->next;
712: }
713: PetscCall(VecDestroy(&xtmp));
714: } else {
715: MatReuse scall;
716: MatNullSpace *nullsp = NULL;
718: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
719: PetscCall(MatGetNullSpaces(nsplit, jac->pmat, &nullsp));
720: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->pmat[i]));
721: scall = MAT_INITIAL_MATRIX;
722: } else scall = MAT_REUSE_MATRIX;
724: for (i = 0; i < nsplit; i++) {
725: Mat pmat;
727: /* Check for matrix attached to IS */
728: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&pmat));
729: if (!pmat) PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, scall, &jac->pmat[i]));
730: ilink = ilink->next;
731: }
732: if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->pmat, &nullsp));
733: }
734: if (jac->diag_use_amat) {
735: ilink = jac->head;
736: if (!jac->mat) {
737: PetscCall(PetscMalloc1(nsplit, &jac->mat));
738: for (i = 0; i < nsplit; i++) {
739: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->mat[i]));
740: ilink = ilink->next;
741: }
742: } else {
743: MatReuse scall;
744: MatNullSpace *nullsp = NULL;
746: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
747: PetscCall(MatGetNullSpaces(nsplit, jac->mat, &nullsp));
748: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->mat[i]));
749: scall = MAT_INITIAL_MATRIX;
750: } else scall = MAT_REUSE_MATRIX;
752: for (i = 0; i < nsplit; i++) {
753: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, scall, &jac->mat[i]));
754: ilink = ilink->next;
755: }
756: if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->mat, &nullsp));
757: }
758: } else {
759: jac->mat = jac->pmat;
760: }
762: /* Check for null space attached to IS */
763: ilink = jac->head;
764: for (i = 0; i < nsplit; i++) {
765: MatNullSpace sp;
767: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nullspace", (PetscObject *)&sp));
768: if (sp) PetscCall(MatSetNullSpace(jac->mat[i], sp));
769: ilink = ilink->next;
770: }
772: if (jac->type != PC_COMPOSITE_ADDITIVE && jac->type != PC_COMPOSITE_SCHUR && jac->type != PC_COMPOSITE_GKB) {
773: /* extract the rows of the matrix associated with each field: used for efficient computation of residual inside algorithm */
774: /* FIXME: Can/should we reuse jac->mat whenever (jac->diag_use_amat) is true? */
775: ilink = jac->head;
776: if (nsplit == 2 && jac->type == PC_COMPOSITE_MULTIPLICATIVE) {
777: /* 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 */
778: if (!jac->Afield) {
779: PetscCall(PetscCalloc1(nsplit, &jac->Afield));
780: if (jac->offdiag_use_amat) {
781: PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1]));
782: } else {
783: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1]));
784: }
785: } else {
786: MatReuse scall;
788: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
789: PetscCall(MatDestroy(&jac->Afield[1]));
790: scall = MAT_INITIAL_MATRIX;
791: } else scall = MAT_REUSE_MATRIX;
793: if (jac->offdiag_use_amat) {
794: PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, scall, &jac->Afield[1]));
795: } else {
796: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, scall, &jac->Afield[1]));
797: }
798: }
799: } else {
800: if (!jac->Afield) {
801: PetscCall(PetscMalloc1(nsplit, &jac->Afield));
802: for (i = 0; i < nsplit; i++) {
803: if (jac->offdiag_use_amat) {
804: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i]));
805: } else {
806: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i]));
807: }
808: ilink = ilink->next;
809: }
810: } else {
811: MatReuse scall;
812: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
813: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->Afield[i]));
814: scall = MAT_INITIAL_MATRIX;
815: } else scall = MAT_REUSE_MATRIX;
817: for (i = 0; i < nsplit; i++) {
818: if (jac->offdiag_use_amat) {
819: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, scall, &jac->Afield[i]));
820: } else {
821: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, scall, &jac->Afield[i]));
822: }
823: ilink = ilink->next;
824: }
825: }
826: }
827: }
829: if (jac->type == PC_COMPOSITE_SCHUR) {
830: IS ccis;
831: PetscBool isset, isspd = PETSC_FALSE, issym = PETSC_FALSE, flg;
832: PetscInt rstart, rend;
833: char lscname[256];
834: PetscObject LSC_L;
836: PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use Schur complement preconditioner you must have exactly 2 fields");
838: /* If pc->mat is SPD, don't scale by -1 the Schur complement */
839: PetscCall(MatIsSPDKnown(pc->pmat, &isset, &isspd));
840: if (jac->schurscale == (PetscScalar)-1.0) jac->schurscale = (isset && isspd) ? 1.0 : -1.0;
841: PetscCall(MatIsSymmetricKnown(pc->pmat, &isset, &issym));
843: /* When extracting off-diagonal submatrices, we take complements from this range */
844: PetscCall(MatGetOwnershipRangeColumn(pc->mat, &rstart, &rend));
845: PetscCall(PetscObjectTypeCompareAny(jac->offdiag_use_amat ? (PetscObject)pc->mat : (PetscObject)pc->pmat, &flg, MATSEQSBAIJ, MATMPISBAIJ, ""));
847: if (jac->schur) {
848: KSP kspA = jac->head->ksp, kspInner = NULL, kspUpper = jac->kspupper;
849: MatReuse scall;
851: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
852: scall = MAT_INITIAL_MATRIX;
853: PetscCall(MatDestroy(&jac->B));
854: PetscCall(MatDestroy(&jac->C));
855: } else scall = MAT_REUSE_MATRIX;
857: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
858: ilink = jac->head;
859: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
860: if (jac->offdiag_use_amat) {
861: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, scall, &jac->B));
862: } else {
863: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, scall, &jac->B));
864: }
865: PetscCall(ISDestroy(&ccis));
866: if (!flg) {
867: ilink = ilink->next;
868: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
869: if (jac->offdiag_use_amat) {
870: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, scall, &jac->C));
871: } else {
872: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, scall, &jac->C));
873: }
874: PetscCall(ISDestroy(&ccis));
875: } else {
876: PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &isset, &flg));
877: if (isset && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C));
878: else PetscCall(MatCreateTranspose(jac->B, &jac->C));
879: }
880: PetscCall(MatSchurComplementUpdateSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1]));
881: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) {
882: PetscCall(MatDestroy(&jac->schurp));
883: PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp));
884: } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL && jac->kspupper != jac->head->ksp) {
885: PetscCall(MatDestroy(&jac->schur_user));
886: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
887: }
888: if (kspA != kspInner) PetscCall(KSPSetOperators(kspA, jac->mat[0], jac->pmat[0]));
889: if (kspUpper != kspA) PetscCall(KSPSetOperators(kspUpper, jac->mat[0], jac->pmat[0]));
890: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac)));
891: } else {
892: const char *Dprefix;
893: char schurprefix[256], schurmatprefix[256];
894: char schurtestoption[256];
895: MatNullSpace sp;
896: KSP kspt;
898: /* extract the A01 and A10 matrices */
899: ilink = jac->head;
900: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
901: if (jac->offdiag_use_amat) {
902: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
903: } else {
904: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
905: }
906: PetscCall(ISDestroy(&ccis));
907: ilink = ilink->next;
908: if (!flg) {
909: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
910: if (jac->offdiag_use_amat) {
911: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
912: } else {
913: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
914: }
915: PetscCall(ISDestroy(&ccis));
916: } else {
917: PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &isset, &flg));
918: if (isset && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C));
919: else PetscCall(MatCreateTranspose(jac->B, &jac->C));
920: }
921: /* Use mat[0] (diagonal block of Amat) preconditioned by pmat[0] to define Schur complement */
922: PetscCall(MatCreate(((PetscObject)jac->mat[0])->comm, &jac->schur));
923: PetscCall(MatSetType(jac->schur, MATSCHURCOMPLEMENT));
924: PetscCall(MatSchurComplementSetSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1]));
925: PetscCall(PetscSNPrintf(schurmatprefix, sizeof(schurmatprefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
926: PetscCall(MatSetOptionsPrefix(jac->schur, schurmatprefix));
927: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspt));
928: PetscCall(KSPSetOptionsPrefix(kspt, schurmatprefix));
930: /* Note: this is not true in general */
931: PetscCall(MatGetNullSpace(jac->mat[1], &sp));
932: if (sp) PetscCall(MatSetNullSpace(jac->schur, sp));
934: PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_inner_", ilink->splitname));
935: PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg));
936: if (flg) {
937: DM dmInner;
938: KSP kspInner;
939: PC pcInner;
941: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
942: PetscCall(KSPReset(kspInner));
943: PetscCall(KSPSetOperators(kspInner, jac->mat[0], jac->pmat[0]));
944: PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_inner_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
945: /* Indent this deeper to emphasize the "inner" nature of this solver. */
946: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner, (PetscObject)pc, 2));
947: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner->pc, (PetscObject)pc, 2));
948: PetscCall(KSPSetOptionsPrefix(kspInner, schurprefix));
950: /* Set DM for new solver */
951: PetscCall(KSPGetDM(jac->head->ksp, &dmInner));
952: PetscCall(KSPSetDM(kspInner, dmInner));
953: PetscCall(KSPSetDMActive(kspInner, PETSC_FALSE));
955: /* Defaults to PCKSP as preconditioner */
956: PetscCall(KSPGetPC(kspInner, &pcInner));
957: PetscCall(PCSetType(pcInner, PCKSP));
958: PetscCall(PCKSPSetKSP(pcInner, jac->head->ksp));
959: } else {
960: /* Use the outer solver for the inner solve, but revert the KSPPREONLY from PCFieldSplitSetFields_FieldSplit or
961: * PCFieldSplitSetIS_FieldSplit. We don't want KSPPREONLY because it makes the Schur complement inexact,
962: * preventing Schur complement reduction to be an accurate solve. Usually when an iterative solver is used for
963: * S = D - C A_inner^{-1} B, we expect S to be defined using an accurate definition of A_inner^{-1}, so we make
964: * GMRES the default. Note that it is also common to use PREONLY for S, in which case S may not be used
965: * directly, and the user is responsible for setting an inexact method for fieldsplit's A^{-1}. */
966: PetscCall(KSPSetType(jac->head->ksp, KSPGMRES));
967: PetscCall(MatSchurComplementSetKSP(jac->schur, jac->head->ksp));
968: }
969: PetscCall(KSPSetOperators(jac->head->ksp, jac->mat[0], jac->pmat[0]));
970: PetscCall(KSPSetFromOptions(jac->head->ksp));
971: PetscCall(MatSetFromOptions(jac->schur));
973: PetscCall(PetscObjectTypeCompare((PetscObject)jac->schur, MATSCHURCOMPLEMENT, &flg));
974: if (flg) { /* Need to do this otherwise PCSetUp_KSP will overwrite the amat of jac->head->ksp */
975: KSP kspInner;
976: PC pcInner;
978: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
979: PetscCall(KSPGetPC(kspInner, &pcInner));
980: PetscCall(PetscObjectTypeCompare((PetscObject)pcInner, PCKSP, &flg));
981: if (flg) {
982: KSP ksp;
984: PetscCall(PCKSPGetKSP(pcInner, &ksp));
985: if (ksp == jac->head->ksp) PetscCall(PCSetUseAmat(pcInner, PETSC_TRUE));
986: }
987: }
988: PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_upper_", ilink->splitname));
989: PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg));
990: if (flg) {
991: DM dmInner;
993: PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_upper_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
994: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspupper));
995: PetscCall(KSPSetNestLevel(jac->kspupper, pc->kspnestlevel));
996: PetscCall(KSPSetErrorIfNotConverged(jac->kspupper, pc->erroriffailure));
997: PetscCall(KSPSetOptionsPrefix(jac->kspupper, schurprefix));
998: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper, (PetscObject)pc, 1));
999: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper->pc, (PetscObject)pc, 1));
1000: PetscCall(KSPGetDM(jac->head->ksp, &dmInner));
1001: PetscCall(KSPSetDM(jac->kspupper, dmInner));
1002: PetscCall(KSPSetDMActive(jac->kspupper, PETSC_FALSE));
1003: PetscCall(KSPSetFromOptions(jac->kspupper));
1004: PetscCall(KSPSetOperators(jac->kspupper, jac->mat[0], jac->pmat[0]));
1005: PetscCall(VecDuplicate(jac->head->x, &jac->head->z));
1006: } else {
1007: jac->kspupper = jac->head->ksp;
1008: PetscCall(PetscObjectReference((PetscObject)jac->head->ksp));
1009: }
1011: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp));
1012: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspschur));
1013: PetscCall(KSPSetNestLevel(jac->kspschur, pc->kspnestlevel));
1014: PetscCall(KSPSetErrorIfNotConverged(jac->kspschur, pc->erroriffailure));
1015: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspschur, (PetscObject)pc, 1));
1016: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) {
1017: PC pcschur;
1018: PetscCall(KSPGetPC(jac->kspschur, &pcschur));
1019: PetscCall(PCSetType(pcschur, PCNONE));
1020: /* Note: This is bad if there exist preconditioners for MATSCHURCOMPLEMENT */
1021: } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL) {
1022: if (jac->schurfactorization != PC_FIELDSPLIT_SCHUR_FACT_FULL || jac->kspupper != jac->head->ksp) PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1023: }
1024: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac)));
1025: PetscCall(KSPGetOptionsPrefix(jac->head->next->ksp, &Dprefix));
1026: PetscCall(KSPSetOptionsPrefix(jac->kspschur, Dprefix));
1027: /* propagate DM */
1028: {
1029: DM sdm;
1030: PetscCall(KSPGetDM(jac->head->next->ksp, &sdm));
1031: if (sdm) {
1032: PetscCall(KSPSetDM(jac->kspschur, sdm));
1033: PetscCall(KSPSetDMActive(jac->kspschur, PETSC_FALSE));
1034: }
1035: }
1036: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
1037: /* need to call this every time, since the jac->kspschur is freshly created, otherwise its options never get set */
1038: PetscCall(KSPSetFromOptions(jac->kspschur));
1039: }
1040: PetscCall(MatAssemblyBegin(jac->schur, MAT_FINAL_ASSEMBLY));
1041: PetscCall(MatAssemblyEnd(jac->schur, MAT_FINAL_ASSEMBLY));
1042: if (issym) PetscCall(MatSetOption(jac->schur, MAT_SYMMETRIC, PETSC_TRUE));
1043: if (isspd) PetscCall(MatSetOption(jac->schur, MAT_SPD, PETSC_TRUE));
1045: /* HACK: special support to forward L and Lp matrices that might be used by PCLSC */
1046: PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_L", ilink->splitname));
1047: PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, &LSC_L));
1048: if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, &LSC_L));
1049: if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_L", LSC_L));
1050: PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_Lp", ilink->splitname));
1051: PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, &LSC_L));
1052: if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, &LSC_L));
1053: if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_Lp", LSC_L));
1054: } else if (jac->type == PC_COMPOSITE_GKB) {
1055: IS ccis;
1056: PetscInt rstart, rend;
1058: PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use GKB preconditioner you must have exactly 2 fields");
1060: ilink = jac->head;
1062: /* When extracting off-diagonal submatrices, we take complements from this range */
1063: PetscCall(MatGetOwnershipRangeColumn(pc->mat, &rstart, &rend));
1065: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
1066: if (jac->offdiag_use_amat) {
1067: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
1068: } else {
1069: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->B));
1070: }
1071: PetscCall(ISDestroy(&ccis));
1072: /* Create work vectors for GKB algorithm */
1073: PetscCall(VecDuplicate(ilink->x, &jac->u));
1074: PetscCall(VecDuplicate(ilink->x, &jac->Hu));
1075: PetscCall(VecDuplicate(ilink->x, &jac->w2));
1076: ilink = ilink->next;
1077: PetscCall(ISComplement(ilink->is_col, rstart, rend, &ccis));
1078: if (jac->offdiag_use_amat) {
1079: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
1080: } else {
1081: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ccis, MAT_INITIAL_MATRIX, &jac->C));
1082: }
1083: PetscCall(ISDestroy(&ccis));
1084: /* Create work vectors for GKB algorithm */
1085: PetscCall(VecDuplicate(ilink->x, &jac->v));
1086: PetscCall(VecDuplicate(ilink->x, &jac->d));
1087: PetscCall(VecDuplicate(ilink->x, &jac->w1));
1088: PetscCall(MatGolubKahanComputeExplicitOperator(jac->mat[0], jac->B, jac->C, &jac->H, jac->gkbnu));
1089: PetscCall(PetscCalloc1(jac->gkbdelay, &jac->vecz));
1091: ilink = jac->head;
1092: PetscCall(KSPSetOperators(ilink->ksp, jac->H, jac->H));
1093: if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp));
1094: /* Create gkb_monitor context */
1095: if (jac->gkbmonitor) {
1096: PetscInt tablevel;
1097: PetscCall(PetscViewerCreate(PETSC_COMM_WORLD, &jac->gkbviewer));
1098: PetscCall(PetscViewerSetType(jac->gkbviewer, PETSCVIEWERASCII));
1099: PetscCall(PetscObjectGetTabLevel((PetscObject)ilink->ksp, &tablevel));
1100: PetscCall(PetscViewerASCIISetTab(jac->gkbviewer, tablevel));
1101: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)ilink->ksp, 1));
1102: }
1103: } else {
1104: /* set up the individual splits' PCs */
1105: i = 0;
1106: ilink = jac->head;
1107: while (ilink) {
1108: PetscCall(KSPSetOperators(ilink->ksp, jac->mat[i], jac->pmat[i]));
1109: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
1110: if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp));
1111: i++;
1112: ilink = ilink->next;
1113: }
1114: }
1116: /* Set coordinates to the sub PC objects whenever these are set */
1117: if (jac->coordinates_set) {
1118: PC pc_coords;
1119: if (jac->type == PC_COMPOSITE_SCHUR) {
1120: // Head is first block.
1121: PetscCall(KSPGetPC(jac->head->ksp, &pc_coords));
1122: PetscCall(PCSetCoordinates(pc_coords, jac->head->dim, jac->head->ndofs, jac->head->coords));
1123: // Second one is Schur block, but its KSP object is in kspschur.
1124: PetscCall(KSPGetPC(jac->kspschur, &pc_coords));
1125: PetscCall(PCSetCoordinates(pc_coords, jac->head->next->dim, jac->head->next->ndofs, jac->head->next->coords));
1126: } else if (jac->type == PC_COMPOSITE_GKB) {
1127: PetscCall(PetscInfo(pc, "Warning: Setting coordinates does nothing for the GKB Fieldpslit preconditioner\n"));
1128: } else {
1129: ilink = jac->head;
1130: while (ilink) {
1131: PetscCall(KSPGetPC(ilink->ksp, &pc_coords));
1132: PetscCall(PCSetCoordinates(pc_coords, ilink->dim, ilink->ndofs, ilink->coords));
1133: ilink = ilink->next;
1134: }
1135: }
1136: }
1138: jac->suboptionsset = PETSC_TRUE;
1139: PetscFunctionReturn(PETSC_SUCCESS);
1140: }
1142: static PetscErrorCode PCSetUpOnBlocks_FieldSplit_Schur(PC pc)
1143: {
1144: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1145: PC_FieldSplitLink ilinkA = jac->head;
1146: KSP kspA = ilinkA->ksp, kspUpper = jac->kspupper;
1148: PetscFunctionBegin;
1149: if (jac->schurfactorization == PC_FIELDSPLIT_SCHUR_FACT_FULL && kspUpper != kspA) {
1150: PetscCall(KSPSetUp(kspUpper));
1151: PetscCall(KSPSetUpOnBlocks(kspUpper));
1152: }
1153: PetscCall(KSPSetUp(kspA));
1154: PetscCall(KSPSetUpOnBlocks(kspA));
1155: if (jac->schurpre != PC_FIELDSPLIT_SCHUR_PRE_FULL) {
1156: PetscCall(KSPSetUp(jac->kspschur));
1157: PetscCall(KSPSetUpOnBlocks(jac->kspschur));
1158: } else if (kspUpper == kspA) {
1159: Mat A;
1160: PetscInt m, M, N;
1161: VecType vtype;
1162: PetscMemType mtype;
1163: PetscScalar *array;
1165: PetscCall(MatGetSize(jac->B, &M, &N));
1166: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1167: PetscCall(MatGetVecType(jac->B, &vtype));
1168: PetscCall(VecGetArrayAndMemType(ilinkA->x, &array, &mtype));
1169: PetscCall(VecRestoreArrayAndMemType(ilinkA->x, &array));
1170: if (PetscMemTypeHost(mtype) || (!PetscDefined(HAVE_CUDA) && !PetscDefined(HAVE_HIP))) PetscCall(PetscMalloc1(m * (N + 1), &array));
1171: #if PetscDefined(HAVE_CUDA)
1172: else if (PetscMemTypeCUDA(mtype)) PetscCallCUDA(cudaMalloc((void **)&array, sizeof(PetscScalar) * m * (N + 1)));
1173: #endif
1174: #if PetscDefined(HAVE_HIP)
1175: else if (PetscMemTypeHIP(mtype)) PetscCallHIP(hipMalloc((void **)&array, sizeof(PetscScalar) * m * (N + 1)));
1176: #endif
1177: 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
1178: PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", (PetscObject)A));
1179: PetscCall(MatDestroy(&A));
1180: }
1181: PetscFunctionReturn(PETSC_SUCCESS);
1182: }
1184: static PetscErrorCode PCSetUpOnBlocks_FieldSplit(PC pc)
1185: {
1186: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1187: PC_FieldSplitLink ilink = jac->head;
1189: PetscFunctionBegin;
1190: while (ilink) {
1191: PetscCall(KSPSetUp(ilink->ksp));
1192: PetscCall(KSPSetUpOnBlocks(ilink->ksp));
1193: ilink = ilink->next;
1194: }
1195: PetscFunctionReturn(PETSC_SUCCESS);
1196: }
1198: static PetscErrorCode PCSetUpOnBlocks_FieldSplit_GKB(PC pc)
1199: {
1200: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1201: PC_FieldSplitLink ilinkA = jac->head;
1202: KSP ksp = ilinkA->ksp;
1204: PetscFunctionBegin;
1205: PetscCall(KSPSetUp(ksp));
1206: PetscCall(KSPSetUpOnBlocks(ksp));
1207: PetscFunctionReturn(PETSC_SUCCESS);
1208: }
1210: static PetscErrorCode PCApply_FieldSplit_Schur(PC pc, Vec x, Vec y)
1211: {
1212: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1213: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1214: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1215: Mat AinvB = NULL;
1216: PetscInt N, P;
1218: PetscFunctionBegin;
1219: switch (jac->schurfactorization) {
1220: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1221: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1222: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1223: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1224: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1225: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1226: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1227: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1228: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1229: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1230: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1231: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1232: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1233: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1234: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1235: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1236: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1237: PetscCall(VecScale(ilinkD->y, jac->schurscale));
1238: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1239: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1240: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1241: break;
1242: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1243: /* [A00 0; A10 S], suitable for left preconditioning */
1244: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1245: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1246: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1247: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1248: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1249: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1250: PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x));
1251: PetscCall(VecScale(ilinkD->x, -1.));
1252: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1253: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1254: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1255: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1256: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1257: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1258: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1259: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1260: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1261: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1262: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1263: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1264: break;
1265: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1266: /* [A00 A01; 0 S], suitable for right preconditioning */
1267: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1268: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_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(MatMult(jac->B, ilinkD->y, ilinkA->x));
1276: PetscCall(VecScale(ilinkA->x, -1.));
1277: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1278: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1279: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1280: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1281: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1282: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1283: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1284: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1285: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1286: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1287: break;
1288: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1289: /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1] */
1290: PetscCall(MatGetSize(jac->B, NULL, &P));
1291: N = P;
1292: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1293: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1294: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL));
1295: if (kspUpper == kspA) {
1296: PetscCall(PetscObjectQuery((PetscObject)jac->schur, "AinvB", (PetscObject *)&AinvB));
1297: if (AinvB) {
1298: PetscCall(MatGetSize(AinvB, NULL, &N));
1299: if (N > P) { // first time PCApply_FieldSplit_Schur() is called
1300: PetscMemType mtype;
1301: Vec c = NULL;
1302: PetscScalar *array;
1303: PetscInt m, M;
1305: PetscCall(MatGetSize(jac->B, &M, NULL));
1306: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1307: PetscCall(MatDenseGetArrayAndMemType(AinvB, &array, &mtype));
1308: if (PetscMemTypeHost(mtype) || (!PetscDefined(HAVE_CUDA) && !PetscDefined(HAVE_HIP))) PetscCall(VecCreateMPIWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1309: #if PetscDefined(HAVE_CUDA)
1310: else if (PetscMemTypeCUDA(mtype)) PetscCall(VecCreateMPICUDAWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1311: #endif
1312: #if PetscDefined(HAVE_HIP)
1313: else if (PetscMemTypeHIP(mtype)) PetscCall(VecCreateMPIHIPWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1314: #endif
1315: PetscCall(MatDenseRestoreArrayAndMemType(AinvB, &array));
1316: PetscCall(VecCopy(ilinkA->x, c));
1317: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1318: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, jac->schur_user));
1319: PetscCall(VecCopy(c, ilinkA->y)); // retrieve the solution as the last column of the composed Mat
1320: PetscCall(VecDestroy(&c));
1321: }
1322: }
1323: }
1324: if (N == P) PetscCall(KSPSolve(kspLower, ilinkA->x, ilinkA->y));
1325: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->y));
1326: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL));
1327: PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x));
1328: PetscCall(VecScale(ilinkD->x, -1.0));
1329: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1330: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1332: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1333: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1334: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1335: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1336: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1337: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1338: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1340: if (kspUpper == kspA) {
1341: if (!AinvB) {
1342: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->y));
1343: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1344: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1345: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1346: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1347: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1348: } else PetscCall(MatMultAdd(AinvB, ilinkD->y, ilinkA->y, ilinkA->y));
1349: } else {
1350: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1351: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1352: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1353: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->x));
1354: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1355: PetscCall(KSPSolve(kspUpper, ilinkA->x, ilinkA->z));
1356: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->z));
1357: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1358: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1359: }
1360: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1361: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1362: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1363: }
1364: PetscFunctionReturn(PETSC_SUCCESS);
1365: }
1367: static PetscErrorCode PCApplyTranspose_FieldSplit_Schur(PC pc, Vec x, Vec y)
1368: {
1369: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1370: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1371: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1373: PetscFunctionBegin;
1374: switch (jac->schurfactorization) {
1375: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1376: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1377: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1378: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1379: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1380: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1381: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1382: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1383: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1384: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1385: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1386: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1387: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1388: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1389: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1390: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1391: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1392: PetscCall(VecScale(ilinkD->y, jac->schurscale));
1393: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1394: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1395: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1396: break;
1397: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1398: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1399: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1400: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1401: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1402: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1403: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1404: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1405: PetscCall(VecScale(ilinkD->x, -1.));
1406: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1407: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1408: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1409: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1410: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1411: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1412: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1413: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1414: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1415: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1416: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1417: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1418: break;
1419: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1420: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1421: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1422: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1423: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1424: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1425: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1426: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1427: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1428: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1429: PetscCall(VecScale(ilinkA->x, -1.));
1430: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1431: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1432: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1433: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1434: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1435: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1436: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1437: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1438: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1439: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1440: break;
1441: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1442: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1443: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1444: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1445: PetscCall(KSPSolveTranspose(kspUpper, ilinkA->x, ilinkA->y));
1446: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->y));
1447: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1448: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1449: PetscCall(VecScale(ilinkD->x, -1.0));
1450: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1451: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1453: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1454: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1455: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1456: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1457: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1458: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1459: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1461: if (kspLower == kspA) {
1462: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->y));
1463: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1464: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1465: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1466: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1467: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1468: } else {
1469: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1470: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1471: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1472: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1473: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1474: PetscCall(KSPSolveTranspose(kspLower, ilinkA->x, ilinkA->z));
1475: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->z));
1476: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1477: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1478: }
1479: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1480: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1481: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1482: }
1483: PetscFunctionReturn(PETSC_SUCCESS);
1484: }
1486: #define FieldSplitSplitSolveAdd(ilink, xx, yy) \
1487: ((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) || \
1488: 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) || \
1489: VecScatterEnd(ilink->sctx, ilink->y, yy, ADD_VALUES, SCATTER_REVERSE)))
1491: static PetscErrorCode PCApply_FieldSplit(PC pc, Vec x, Vec y)
1492: {
1493: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1494: PC_FieldSplitLink ilink = jac->head;
1495: PetscInt cnt, bs;
1497: PetscFunctionBegin;
1498: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1499: PetscBool matnest;
1501: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1502: if (jac->defaultsplit && !matnest) {
1503: PetscCall(VecGetBlockSize(x, &bs));
1504: 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);
1505: PetscCall(VecGetBlockSize(y, &bs));
1506: 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);
1507: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1508: while (ilink) {
1509: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1510: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1511: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1512: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1513: ilink = ilink->next;
1514: }
1515: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1516: } else {
1517: PetscCall(VecSet(y, 0.0));
1518: while (ilink) {
1519: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1520: ilink = ilink->next;
1521: }
1522: }
1523: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) {
1524: PetscCall(VecSet(y, 0.0));
1525: /* solve on first block for first block variables */
1526: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1527: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1528: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1529: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1530: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1531: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1532: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1533: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1535: /* compute the residual only onto second block variables using first block variables */
1536: PetscCall(MatMult(jac->Afield[1], ilink->y, ilink->next->x));
1537: ilink = ilink->next;
1538: PetscCall(VecScale(ilink->x, -1.0));
1539: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1540: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1542: /* solve on second block variables */
1543: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1544: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1545: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1546: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1547: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1548: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1549: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1550: if (!jac->w1) {
1551: PetscCall(VecDuplicate(x, &jac->w1));
1552: PetscCall(VecDuplicate(x, &jac->w2));
1553: }
1554: PetscCall(VecSet(y, 0.0));
1555: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1556: cnt = 1;
1557: while (ilink->next) {
1558: ilink = ilink->next;
1559: /* compute the residual only over the part of the vector needed */
1560: PetscCall(MatMult(jac->Afield[cnt++], y, ilink->x));
1561: PetscCall(VecScale(ilink->x, -1.0));
1562: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1563: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1564: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1565: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1566: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1567: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1568: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1569: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1570: }
1571: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1572: cnt -= 2;
1573: while (ilink->previous) {
1574: ilink = ilink->previous;
1575: /* compute the residual only over the part of the vector needed */
1576: PetscCall(MatMult(jac->Afield[cnt--], y, ilink->x));
1577: PetscCall(VecScale(ilink->x, -1.0));
1578: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1579: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1580: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1581: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1582: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1583: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1584: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1585: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1586: }
1587: }
1588: } else SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Unsupported or unknown composition %d", (int)jac->type);
1589: PetscFunctionReturn(PETSC_SUCCESS);
1590: }
1592: static PetscErrorCode PCApply_FieldSplit_GKB(PC pc, Vec x, Vec y)
1593: {
1594: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1595: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1596: KSP ksp = ilinkA->ksp;
1597: Vec u, v, Hu, d, work1, work2;
1598: PetscScalar alpha, z, nrmz2, *vecz;
1599: PetscReal lowbnd, nu, beta;
1600: PetscInt j, iterGKB;
1602: PetscFunctionBegin;
1603: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1604: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1605: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1606: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1608: u = jac->u;
1609: v = jac->v;
1610: Hu = jac->Hu;
1611: d = jac->d;
1612: work1 = jac->w1;
1613: work2 = jac->w2;
1614: vecz = jac->vecz;
1616: /* Change RHS to comply with matrix regularization H = A + nu*B*B' */
1617: /* Add q = q + nu*B*b */
1618: if (jac->gkbnu) {
1619: nu = jac->gkbnu;
1620: PetscCall(VecScale(ilinkD->x, jac->gkbnu));
1621: PetscCall(MatMultAdd(jac->B, ilinkD->x, ilinkA->x, ilinkA->x)); /* q = q + nu*B*b */
1622: } else {
1623: /* Situation when no augmented Lagrangian is used. Then we set inner */
1624: /* matrix N = I in [Ar13], and thus nu = 1. */
1625: nu = 1;
1626: }
1628: /* Transform rhs from [q,tilde{b}] to [0,b] */
1629: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1630: PetscCall(KSPSolve(ksp, ilinkA->x, ilinkA->y));
1631: PetscCall(KSPCheckSolve(ksp, pc, ilinkA->y));
1632: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1633: PetscCall(MatMultHermitianTranspose(jac->B, ilinkA->y, work1));
1634: PetscCall(VecAXPBY(work1, 1.0 / nu, -1.0, ilinkD->x)); /* c = b - B'*x */
1636: /* First step of algorithm */
1637: PetscCall(VecNorm(work1, NORM_2, &beta)); /* beta = sqrt(nu*c'*c)*/
1638: KSPCheckDot(ksp, beta);
1639: beta = PetscSqrtReal(nu) * beta;
1640: PetscCall(VecAXPBY(v, nu / beta, 0.0, work1)); /* v = nu/beta *c */
1641: PetscCall(MatMult(jac->B, v, work2)); /* u = H^{-1}*B*v */
1642: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1643: PetscCall(KSPSolve(ksp, work2, u));
1644: PetscCall(KSPCheckSolve(ksp, pc, u));
1645: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1646: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1647: PetscCall(VecDot(Hu, u, &alpha));
1648: KSPCheckDot(ksp, alpha);
1649: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1650: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1651: PetscCall(VecScale(u, 1.0 / alpha));
1652: PetscCall(VecAXPBY(d, 1.0 / alpha, 0.0, v)); /* v = nu/beta *c */
1654: z = beta / alpha;
1655: vecz[1] = z;
1657: /* Computation of first iterate x(1) and p(1) */
1658: PetscCall(VecAXPY(ilinkA->y, z, u));
1659: PetscCall(VecCopy(d, ilinkD->y));
1660: PetscCall(VecScale(ilinkD->y, -z));
1662: iterGKB = 1;
1663: lowbnd = 2 * jac->gkbtol;
1664: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1666: while (iterGKB < jac->gkbmaxit && lowbnd > jac->gkbtol) {
1667: iterGKB += 1;
1668: PetscCall(MatMultHermitianTranspose(jac->B, u, work1)); /* v <- nu*(B'*u-alpha/nu*v) */
1669: PetscCall(VecAXPBY(v, nu, -alpha, work1));
1670: PetscCall(VecNorm(v, NORM_2, &beta)); /* beta = sqrt(nu)*v'*v */
1671: beta = beta / PetscSqrtReal(nu);
1672: PetscCall(VecScale(v, 1.0 / beta));
1673: PetscCall(MatMult(jac->B, v, work2)); /* u <- H^{-1}*(B*v-beta*H*u) */
1674: PetscCall(MatMult(jac->H, u, Hu));
1675: PetscCall(VecAXPY(work2, -beta, Hu));
1676: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1677: PetscCall(KSPSolve(ksp, work2, u));
1678: PetscCall(KSPCheckSolve(ksp, pc, u));
1679: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1680: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1681: PetscCall(VecDot(Hu, u, &alpha));
1682: KSPCheckDot(ksp, alpha);
1683: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1684: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1685: PetscCall(VecScale(u, 1.0 / alpha));
1687: z = -beta / alpha * z; /* z <- beta/alpha*z */
1688: vecz[0] = z;
1690: /* Computation of new iterate x(i+1) and p(i+1) */
1691: PetscCall(VecAXPBY(d, 1.0 / alpha, -beta / alpha, v)); /* d = (v-beta*d)/alpha */
1692: PetscCall(VecAXPY(ilinkA->y, z, u)); /* r = r + z*u */
1693: PetscCall(VecAXPY(ilinkD->y, -z, d)); /* p = p - z*d */
1694: PetscCall(MatMult(jac->H, ilinkA->y, Hu)); /* ||u||_H = u'*H*u */
1695: PetscCall(VecDot(Hu, ilinkA->y, &nrmz2));
1697: /* Compute Lower Bound estimate */
1698: if (iterGKB > jac->gkbdelay) {
1699: lowbnd = 0.0;
1700: for (j = 0; j < jac->gkbdelay; j++) lowbnd += PetscAbsScalar(vecz[j] * vecz[j]);
1701: lowbnd = PetscSqrtReal(lowbnd / PetscAbsScalar(nrmz2));
1702: }
1704: for (j = 0; j < jac->gkbdelay - 1; j++) vecz[jac->gkbdelay - j - 1] = vecz[jac->gkbdelay - j - 2];
1705: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1706: }
1708: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1709: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1710: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1711: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1712: PetscFunctionReturn(PETSC_SUCCESS);
1713: }
1715: #define FieldSplitSplitSolveAddTranspose(ilink, xx, yy) \
1716: ((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) || \
1717: 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) || \
1718: VecScatterEnd(ilink->sctx, ilink->x, yy, ADD_VALUES, SCATTER_REVERSE)))
1720: static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc, Vec x, Vec y)
1721: {
1722: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1723: PC_FieldSplitLink ilink = jac->head;
1724: PetscInt bs;
1726: PetscFunctionBegin;
1727: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1728: PetscBool matnest;
1730: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1731: if (jac->defaultsplit && !matnest) {
1732: PetscCall(VecGetBlockSize(x, &bs));
1733: 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);
1734: PetscCall(VecGetBlockSize(y, &bs));
1735: 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);
1736: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1737: while (ilink) {
1738: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1739: PetscCall(KSPSolveTranspose(ilink->ksp, ilink->x, ilink->y));
1740: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1741: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1742: ilink = ilink->next;
1743: }
1744: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1745: } else {
1746: PetscCall(VecSet(y, 0.0));
1747: while (ilink) {
1748: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
1749: ilink = ilink->next;
1750: }
1751: }
1752: } else {
1753: if (!jac->w1) {
1754: PetscCall(VecDuplicate(x, &jac->w1));
1755: PetscCall(VecDuplicate(x, &jac->w2));
1756: }
1757: PetscCall(VecSet(y, 0.0));
1758: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1759: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
1760: while (ilink->next) {
1761: ilink = ilink->next;
1762: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
1763: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
1764: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
1765: }
1766: while (ilink->previous) {
1767: ilink = ilink->previous;
1768: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
1769: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
1770: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
1771: }
1772: } else {
1773: while (ilink->next) { /* get to last entry in linked list */
1774: ilink = ilink->next;
1775: }
1776: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
1777: while (ilink->previous) {
1778: ilink = ilink->previous;
1779: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
1780: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
1781: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
1782: }
1783: }
1784: }
1785: PetscFunctionReturn(PETSC_SUCCESS);
1786: }
1788: static PetscErrorCode PCReset_FieldSplit(PC pc)
1789: {
1790: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1791: PC_FieldSplitLink ilink = jac->head, next;
1793: PetscFunctionBegin;
1794: while (ilink) {
1795: PetscCall(KSPDestroy(&ilink->ksp));
1796: PetscCall(VecDestroy(&ilink->x));
1797: PetscCall(VecDestroy(&ilink->y));
1798: PetscCall(VecDestroy(&ilink->z));
1799: PetscCall(VecScatterDestroy(&ilink->sctx));
1800: PetscCall(ISDestroy(&ilink->is));
1801: PetscCall(ISDestroy(&ilink->is_col));
1802: PetscCall(PetscFree(ilink->splitname));
1803: PetscCall(PetscFree(ilink->fields));
1804: PetscCall(PetscFree(ilink->fields_col));
1805: next = ilink->next;
1806: PetscCall(PetscFree(ilink));
1807: ilink = next;
1808: }
1809: jac->head = NULL;
1810: PetscCall(PetscFree2(jac->x, jac->y));
1811: if (jac->mat && jac->mat != jac->pmat) {
1812: PetscCall(MatDestroyMatrices(jac->nsplits, &jac->mat));
1813: } else if (jac->mat) {
1814: jac->mat = NULL;
1815: }
1816: if (jac->pmat) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->pmat));
1817: if (jac->Afield) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->Afield));
1818: jac->nsplits = 0;
1819: PetscCall(VecDestroy(&jac->w1));
1820: PetscCall(VecDestroy(&jac->w2));
1821: if (jac->schur) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", NULL));
1822: PetscCall(MatDestroy(&jac->schur));
1823: PetscCall(MatDestroy(&jac->schurp));
1824: PetscCall(MatDestroy(&jac->schur_user));
1825: PetscCall(KSPDestroy(&jac->kspschur));
1826: PetscCall(KSPDestroy(&jac->kspupper));
1827: PetscCall(MatDestroy(&jac->B));
1828: PetscCall(MatDestroy(&jac->C));
1829: PetscCall(MatDestroy(&jac->H));
1830: PetscCall(VecDestroy(&jac->u));
1831: PetscCall(VecDestroy(&jac->v));
1832: PetscCall(VecDestroy(&jac->Hu));
1833: PetscCall(VecDestroy(&jac->d));
1834: PetscCall(PetscFree(jac->vecz));
1835: PetscCall(PetscViewerDestroy(&jac->gkbviewer));
1836: jac->isrestrict = PETSC_FALSE;
1837: PetscFunctionReturn(PETSC_SUCCESS);
1838: }
1840: static PetscErrorCode PCDestroy_FieldSplit(PC pc)
1841: {
1842: PetscFunctionBegin;
1843: PetscCall(PCReset_FieldSplit(pc));
1844: PetscCall(PetscFree(pc->data));
1845: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", NULL));
1846: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", NULL));
1847: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", NULL));
1848: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", NULL));
1849: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", NULL));
1850: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", NULL));
1851: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", NULL));
1852: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
1853: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
1854: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
1855: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
1856: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
1857: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
1858: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
1859: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
1860: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
1861: PetscFunctionReturn(PETSC_SUCCESS);
1862: }
1864: static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc, PetscOptionItems PetscOptionsObject)
1865: {
1866: PetscInt bs;
1867: PetscBool flg;
1868: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1869: PCCompositeType ctype;
1871: PetscFunctionBegin;
1872: PetscOptionsHeadBegin(PetscOptionsObject, "FieldSplit options");
1873: PetscCall(PetscOptionsBool("-pc_fieldsplit_dm_splits", "Whether to use DMCreateFieldDecomposition() for splits", "PCFieldSplitSetDMSplits", jac->dm_splits, &jac->dm_splits, NULL));
1874: PetscCall(PetscOptionsInt("-pc_fieldsplit_block_size", "Blocksize that defines number of fields", "PCFieldSplitSetBlockSize", jac->bs, &bs, &flg));
1875: if (flg) PetscCall(PCFieldSplitSetBlockSize(pc, bs));
1876: jac->diag_use_amat = pc->useAmat;
1877: 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));
1878: jac->offdiag_use_amat = pc->useAmat;
1879: 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));
1880: PetscCall(PetscOptionsBool("-pc_fieldsplit_detect_saddle_point", "Form 2-way split by detecting zero diagonal entries", "PCFieldSplitSetDetectSaddlePoint", jac->detect, &jac->detect, NULL));
1881: PetscCall(PCFieldSplitSetDetectSaddlePoint(pc, jac->detect)); /* Sets split type and Schur PC type */
1882: PetscCall(PetscOptionsEnum("-pc_fieldsplit_type", "Type of composition", "PCFieldSplitSetType", PCCompositeTypes, (PetscEnum)jac->type, (PetscEnum *)&ctype, &flg));
1883: if (flg) PetscCall(PCFieldSplitSetType(pc, ctype));
1884: /* Only setup fields once */
1885: if (jac->bs > 0 && jac->nsplits == 0) {
1886: /* only allow user to set fields from command line.
1887: otherwise user can set them in PCFieldSplitSetDefaults() */
1888: PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc));
1889: if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n"));
1890: }
1891: if (jac->type == PC_COMPOSITE_SCHUR) {
1892: PetscCall(PetscOptionsGetEnum(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_schur_factorization_type", PCFieldSplitSchurFactTypes, (PetscEnum *)&jac->schurfactorization, &flg));
1893: if (flg) PetscCall(PetscInfo(pc, "Deprecated use of -pc_fieldsplit_schur_factorization_type\n"));
1894: 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));
1895: PetscCall(PetscOptionsEnum("-pc_fieldsplit_schur_precondition", "How to build preconditioner for Schur complement", "PCFieldSplitSetSchurPre", PCFieldSplitSchurPreTypes, (PetscEnum)jac->schurpre, (PetscEnum *)&jac->schurpre, NULL));
1896: PetscCall(PetscOptionsScalar("-pc_fieldsplit_schur_scale", "Scale Schur complement", "PCFieldSplitSetSchurScale", jac->schurscale, &jac->schurscale, NULL));
1897: } else if (jac->type == PC_COMPOSITE_GKB) {
1898: PetscCall(PetscOptionsReal("-pc_fieldsplit_gkb_tol", "The tolerance for the lower bound stopping criterion", "PCFieldSplitSetGKBTol", jac->gkbtol, &jac->gkbtol, NULL));
1899: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_delay", "The delay value for lower bound criterion", "PCFieldSplitSetGKBDelay", jac->gkbdelay, &jac->gkbdelay, NULL));
1900: PetscCall(PetscOptionsBoundedReal("-pc_fieldsplit_gkb_nu", "Parameter in augmented Lagrangian approach", "PCFieldSplitSetGKBNu", jac->gkbnu, &jac->gkbnu, NULL, 0.0));
1901: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_maxit", "Maximum allowed number of iterations", "PCFieldSplitSetGKBMaxit", jac->gkbmaxit, &jac->gkbmaxit, NULL));
1902: PetscCall(PetscOptionsBool("-pc_fieldsplit_gkb_monitor", "Prints number of GKB iterations and error", "PCFieldSplitGKB", jac->gkbmonitor, &jac->gkbmonitor, NULL));
1903: }
1904: /*
1905: In the initial call to this routine the sub-solver data structures do not exist so we cannot call KSPSetFromOptions() on them yet.
1906: 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
1907: is called on the outer solver in case changes were made in the options database
1909: 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()
1910: 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.
1911: Without this extra check test p2p1fetidp_olof_full and others fail with incorrect matrix types.
1913: There could be a negative side effect of calling the KSPSetFromOptions() below.
1915: If one captured the PetscObjectState of the options database one could skip these calls if the database has not changed from the previous call
1916: */
1917: if (jac->issetup) {
1918: PC_FieldSplitLink ilink = jac->head;
1919: if (jac->type == PC_COMPOSITE_SCHUR) {
1920: if (jac->kspupper && jac->kspupper->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspupper));
1921: if (jac->kspschur && jac->kspschur->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspschur));
1922: }
1923: while (ilink) {
1924: if (ilink->ksp->totalits > 0) PetscCall(KSPSetFromOptions(ilink->ksp));
1925: ilink = ilink->next;
1926: }
1927: }
1928: PetscOptionsHeadEnd();
1929: PetscFunctionReturn(PETSC_SUCCESS);
1930: }
1932: static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc, const char splitname[], PetscInt n, const PetscInt *fields, const PetscInt *fields_col)
1933: {
1934: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1935: PC_FieldSplitLink ilink, next = jac->head;
1936: char prefix[128];
1937: PetscInt i;
1938: PetscLogEvent nse;
1940: PetscFunctionBegin;
1941: if (jac->splitdefined) {
1942: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
1943: PetscFunctionReturn(PETSC_SUCCESS);
1944: }
1945: for (i = 0; i < n; i++) PetscCheck(fields[i] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", fields[i]);
1946: PetscCall(PetscNew(&ilink));
1947: if (splitname) {
1948: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
1949: } else {
1950: PetscCall(PetscMalloc1(3, &ilink->splitname));
1951: PetscCall(PetscSNPrintf(ilink->splitname, 2, "%" PetscInt_FMT, jac->nsplits));
1952: }
1953: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
1954: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
1955: PetscCall(PetscMalloc1(n, &ilink->fields));
1956: PetscCall(PetscArraycpy(ilink->fields, fields, n));
1957: PetscCall(PetscMalloc1(n, &ilink->fields_col));
1958: PetscCall(PetscArraycpy(ilink->fields_col, fields_col, n));
1960: ilink->nfields = n;
1961: ilink->next = NULL;
1962: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
1963: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
1964: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
1965: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
1966: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
1968: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
1969: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
1971: if (!next) {
1972: jac->head = ilink;
1973: ilink->previous = NULL;
1974: } else {
1975: while (next->next) next = next->next;
1976: next->next = ilink;
1977: ilink->previous = next;
1978: }
1979: jac->nsplits++;
1980: PetscFunctionReturn(PETSC_SUCCESS);
1981: }
1983: static PetscErrorCode PCFieldSplitSchurGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
1984: {
1985: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1987: PetscFunctionBegin;
1988: *subksp = NULL;
1989: if (n) *n = 0;
1990: if (jac->type == PC_COMPOSITE_SCHUR) {
1991: PetscInt nn;
1993: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitSchurGetSubKSP()");
1994: PetscCheck(jac->nsplits == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unexpected number of splits %" PetscInt_FMT " != 2", jac->nsplits);
1995: nn = jac->nsplits + (jac->kspupper != jac->head->ksp ? 1 : 0);
1996: PetscCall(PetscMalloc1(nn, subksp));
1997: (*subksp)[0] = jac->head->ksp;
1998: (*subksp)[1] = jac->kspschur;
1999: if (jac->kspupper != jac->head->ksp) (*subksp)[2] = jac->kspupper;
2000: if (n) *n = nn;
2001: }
2002: PetscFunctionReturn(PETSC_SUCCESS);
2003: }
2005: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc, PetscInt *n, KSP **subksp)
2006: {
2007: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2009: PetscFunctionBegin;
2010: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitGetSubKSP()");
2011: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2012: PetscCall(MatSchurComplementGetKSP(jac->schur, *subksp));
2014: (*subksp)[1] = jac->kspschur;
2015: if (n) *n = jac->nsplits;
2016: PetscFunctionReturn(PETSC_SUCCESS);
2017: }
2019: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
2020: {
2021: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2022: PetscInt cnt = 0;
2023: PC_FieldSplitLink ilink = jac->head;
2025: PetscFunctionBegin;
2026: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2027: while (ilink) {
2028: (*subksp)[cnt++] = ilink->ksp;
2029: ilink = ilink->next;
2030: }
2031: 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);
2032: if (n) *n = jac->nsplits;
2033: PetscFunctionReturn(PETSC_SUCCESS);
2034: }
2036: /*@
2037: PCFieldSplitRestrictIS - Restricts the fieldsplit `IS`s to be within a given `IS`.
2039: Input Parameters:
2040: + pc - the preconditioner context
2041: - isy - the index set that defines the indices to which the fieldsplit is to be restricted
2043: Level: advanced
2045: Developer Notes:
2046: It seems the resulting `IS`s will not cover the entire space, so
2047: how can they define a convergent preconditioner? Needs explaining.
2049: .seealso: [](sec_block_matrices), `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2050: @*/
2051: PetscErrorCode PCFieldSplitRestrictIS(PC pc, IS isy)
2052: {
2053: PetscFunctionBegin;
2056: PetscTryMethod(pc, "PCFieldSplitRestrictIS_C", (PC, IS), (pc, isy));
2057: PetscFunctionReturn(PETSC_SUCCESS);
2058: }
2060: static PetscErrorCode PCFieldSplitRestrictIS_FieldSplit(PC pc, IS isy)
2061: {
2062: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2063: PC_FieldSplitLink ilink = jac->head, next;
2064: PetscInt localsize, size, sizez, i;
2065: const PetscInt *ind, *indz;
2066: PetscInt *indc, *indcz;
2067: PetscBool flg;
2069: PetscFunctionBegin;
2070: PetscCall(ISGetLocalSize(isy, &localsize));
2071: PetscCallMPI(MPI_Scan(&localsize, &size, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)isy)));
2072: size -= localsize;
2073: while (ilink) {
2074: IS isrl, isr;
2075: PC subpc;
2076: PetscCall(ISEmbed(ilink->is, isy, PETSC_TRUE, &isrl));
2077: PetscCall(ISGetLocalSize(isrl, &localsize));
2078: PetscCall(PetscMalloc1(localsize, &indc));
2079: PetscCall(ISGetIndices(isrl, &ind));
2080: PetscCall(PetscArraycpy(indc, ind, localsize));
2081: PetscCall(ISRestoreIndices(isrl, &ind));
2082: PetscCall(ISDestroy(&isrl));
2083: for (i = 0; i < localsize; i++) *(indc + i) += size;
2084: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)isy), localsize, indc, PETSC_OWN_POINTER, &isr));
2085: PetscCall(PetscObjectReference((PetscObject)isr));
2086: PetscCall(ISDestroy(&ilink->is));
2087: ilink->is = isr;
2088: PetscCall(PetscObjectReference((PetscObject)isr));
2089: PetscCall(ISDestroy(&ilink->is_col));
2090: ilink->is_col = isr;
2091: PetscCall(ISDestroy(&isr));
2092: PetscCall(KSPGetPC(ilink->ksp, &subpc));
2093: PetscCall(PetscObjectTypeCompare((PetscObject)subpc, PCFIELDSPLIT, &flg));
2094: if (flg) {
2095: IS iszl, isz;
2096: MPI_Comm comm;
2097: PetscCall(ISGetLocalSize(ilink->is, &localsize));
2098: comm = PetscObjectComm((PetscObject)ilink->is);
2099: PetscCall(ISEmbed(isy, ilink->is, PETSC_TRUE, &iszl));
2100: PetscCallMPI(MPI_Scan(&localsize, &sizez, 1, MPIU_INT, MPI_SUM, comm));
2101: sizez -= localsize;
2102: PetscCall(ISGetLocalSize(iszl, &localsize));
2103: PetscCall(PetscMalloc1(localsize, &indcz));
2104: PetscCall(ISGetIndices(iszl, &indz));
2105: PetscCall(PetscArraycpy(indcz, indz, localsize));
2106: PetscCall(ISRestoreIndices(iszl, &indz));
2107: PetscCall(ISDestroy(&iszl));
2108: for (i = 0; i < localsize; i++) *(indcz + i) += sizez;
2109: PetscCall(ISCreateGeneral(comm, localsize, indcz, PETSC_OWN_POINTER, &isz));
2110: PetscCall(PCFieldSplitRestrictIS(subpc, isz));
2111: PetscCall(ISDestroy(&isz));
2112: }
2113: next = ilink->next;
2114: ilink = next;
2115: }
2116: jac->isrestrict = PETSC_TRUE;
2117: PetscFunctionReturn(PETSC_SUCCESS);
2118: }
2120: static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc, const char splitname[], IS is)
2121: {
2122: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2123: PC_FieldSplitLink ilink, next = jac->head;
2124: char prefix[128];
2125: PetscLogEvent nse;
2127: PetscFunctionBegin;
2128: if (jac->splitdefined) {
2129: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
2130: PetscFunctionReturn(PETSC_SUCCESS);
2131: }
2132: PetscCall(PetscNew(&ilink));
2133: if (splitname) {
2134: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
2135: } else {
2136: PetscCall(PetscMalloc1(8, &ilink->splitname));
2137: PetscCall(PetscSNPrintf(ilink->splitname, 7, "%" PetscInt_FMT, jac->nsplits));
2138: }
2139: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
2140: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
2141: PetscCall(PetscObjectReference((PetscObject)is));
2142: PetscCall(ISDestroy(&ilink->is));
2143: ilink->is = is;
2144: PetscCall(PetscObjectReference((PetscObject)is));
2145: PetscCall(ISDestroy(&ilink->is_col));
2146: ilink->is_col = is;
2147: ilink->next = NULL;
2148: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
2149: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
2150: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
2151: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
2152: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
2154: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
2155: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
2157: if (!next) {
2158: jac->head = ilink;
2159: ilink->previous = NULL;
2160: } else {
2161: while (next->next) next = next->next;
2162: next->next = ilink;
2163: ilink->previous = next;
2164: }
2165: jac->nsplits++;
2166: PetscFunctionReturn(PETSC_SUCCESS);
2167: }
2169: /*@
2170: PCFieldSplitSetFields - Sets the fields that define one particular split in `PCFIELDSPLIT`
2172: Logically Collective
2174: Input Parameters:
2175: + pc - the preconditioner context
2176: . splitname - name of this split, if `NULL` the number of the split is used
2177: . n - the number of fields in this split
2178: . fields - the fields in this split
2179: - 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
2180: of the matrix and `fields_col` provides the column indices for that block
2182: Options Database Key:
2183: . -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the `%d`'th split
2185: Level: intermediate
2187: Notes:
2188: Use `PCFieldSplitSetIS()` to set a general set of indices as a split.
2190: If the matrix used to construct the preconditioner is `MATNEST` then field i refers to the `is_row[i]` `IS` passed to `MatCreateNest()`.
2192: If the matrix used to construct the preconditioner is not `MATNEST` then
2193: `PCFieldSplitSetFields()` is for defining fields as strided blocks (based on the block size provided to the matrix with `MatSetBlockSize()` or
2194: to the `PC` with `PCFieldSplitSetBlockSize()`). For example, if the block
2195: 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
2196: 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x23x56x8.. x12x45x78x....
2197: where the numbered entries indicate what is in the split.
2199: This function is called once per split (it creates a new split each time). Solve options
2200: for this split will be available under the prefix `-fieldsplit_SPLITNAME_`.
2202: `PCFieldSplitSetIS()` does not support having a `fields_col` different from `fields`
2204: Developer Notes:
2205: This routine does not actually create the `IS` representing the split, that is delayed
2206: until `PCSetUp_FieldSplit()`, because information about the vector/matrix layouts may not be
2207: available when this routine is called.
2209: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetIS()`, `PCFieldSplitRestrictIS()`,
2210: `MatSetBlockSize()`, `MatCreateNest()`
2211: @*/
2212: PetscErrorCode PCFieldSplitSetFields(PC pc, const char splitname[], PetscInt n, const PetscInt fields[], const PetscInt fields_col[])
2213: {
2214: PetscFunctionBegin;
2216: PetscAssertPointer(splitname, 2);
2217: PetscCheck(n >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Provided number of fields %" PetscInt_FMT " in split \"%s\" not positive", n, splitname);
2218: PetscAssertPointer(fields, 4);
2219: PetscTryMethod(pc, "PCFieldSplitSetFields_C", (PC, const char[], PetscInt, const PetscInt *, const PetscInt *), (pc, splitname, n, fields, fields_col));
2220: PetscFunctionReturn(PETSC_SUCCESS);
2221: }
2223: /*@
2224: PCFieldSplitSetDiagUseAmat - set flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2225: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2227: Logically Collective
2229: Input Parameters:
2230: + pc - the preconditioner object
2231: - flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2233: Options Database Key:
2234: . -pc_fieldsplit_diag_use_amat - use the Amat to provide the diagonal blocks
2236: Level: intermediate
2238: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetDiagUseAmat()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFIELDSPLIT`
2239: @*/
2240: PetscErrorCode PCFieldSplitSetDiagUseAmat(PC pc, PetscBool flg)
2241: {
2242: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2243: PetscBool isfs;
2245: PetscFunctionBegin;
2247: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2248: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2249: jac->diag_use_amat = flg;
2250: PetscFunctionReturn(PETSC_SUCCESS);
2251: }
2253: /*@
2254: PCFieldSplitGetDiagUseAmat - get the flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2255: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2257: Logically Collective
2259: Input Parameter:
2260: . pc - the preconditioner object
2262: Output Parameter:
2263: . flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2265: Level: intermediate
2267: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetDiagUseAmat()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFIELDSPLIT`
2268: @*/
2269: PetscErrorCode PCFieldSplitGetDiagUseAmat(PC pc, PetscBool *flg)
2270: {
2271: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2272: PetscBool isfs;
2274: PetscFunctionBegin;
2276: PetscAssertPointer(flg, 2);
2277: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2278: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2279: *flg = jac->diag_use_amat;
2280: PetscFunctionReturn(PETSC_SUCCESS);
2281: }
2283: /*@
2284: PCFieldSplitSetOffDiagUseAmat - set flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2285: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2287: Logically Collective
2289: Input Parameters:
2290: + pc - the preconditioner object
2291: - flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2293: Options Database Key:
2294: . -pc_fieldsplit_off_diag_use_amat <bool> - use the Amat to extract the off-diagonal blocks
2296: Level: intermediate
2298: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFieldSplitSetDiagUseAmat()`, `PCFIELDSPLIT`
2299: @*/
2300: PetscErrorCode PCFieldSplitSetOffDiagUseAmat(PC pc, PetscBool flg)
2301: {
2302: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2303: PetscBool isfs;
2305: PetscFunctionBegin;
2307: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2308: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2309: jac->offdiag_use_amat = flg;
2310: PetscFunctionReturn(PETSC_SUCCESS);
2311: }
2313: /*@
2314: PCFieldSplitGetOffDiagUseAmat - get the flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2315: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2317: Logically Collective
2319: Input Parameter:
2320: . pc - the preconditioner object
2322: Output Parameter:
2323: . flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2325: Level: intermediate
2327: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFieldSplitGetDiagUseAmat()`, `PCFIELDSPLIT`
2328: @*/
2329: PetscErrorCode PCFieldSplitGetOffDiagUseAmat(PC pc, PetscBool *flg)
2330: {
2331: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2332: PetscBool isfs;
2334: PetscFunctionBegin;
2336: PetscAssertPointer(flg, 2);
2337: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2338: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2339: *flg = jac->offdiag_use_amat;
2340: PetscFunctionReturn(PETSC_SUCCESS);
2341: }
2343: /*@
2344: PCFieldSplitSetIS - Sets the exact elements for a split in a `PCFIELDSPLIT`
2346: Logically Collective
2348: Input Parameters:
2349: + pc - the preconditioner context
2350: . splitname - name of this split, if `NULL` the number of the split is used
2351: - is - the index set that defines the elements in this split
2353: Level: intermediate
2355: Notes:
2356: Use `PCFieldSplitSetFields()`, for splits defined by strided `IS` based on the matrix block size or the `is_rows[]` passed into `MATNEST`
2358: This function is called once per split (it creates a new split each time). Solve options
2359: for this split will be available under the prefix -fieldsplit_SPLITNAME_.
2361: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetFields()`
2362: @*/
2363: PetscErrorCode PCFieldSplitSetIS(PC pc, const char splitname[], IS is)
2364: {
2365: PetscFunctionBegin;
2367: if (splitname) PetscAssertPointer(splitname, 2);
2369: PetscTryMethod(pc, "PCFieldSplitSetIS_C", (PC, const char[], IS), (pc, splitname, is));
2370: PetscFunctionReturn(PETSC_SUCCESS);
2371: }
2373: /*@
2374: PCFieldSplitGetIS - Retrieves the elements for a split as an `IS`
2376: Logically Collective
2378: Input Parameters:
2379: + pc - the preconditioner context
2380: - splitname - name of this split
2382: Output Parameter:
2383: . is - the index set that defines the elements in this split, or `NULL` if the split is not found
2385: Level: intermediate
2387: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetIS()`, `PCFieldSplitGetISByIndex()`
2388: @*/
2389: PetscErrorCode PCFieldSplitGetIS(PC pc, const char splitname[], IS *is)
2390: {
2391: PetscFunctionBegin;
2393: PetscAssertPointer(splitname, 2);
2394: PetscAssertPointer(is, 3);
2395: {
2396: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2397: PC_FieldSplitLink ilink = jac->head;
2398: PetscBool found;
2400: *is = NULL;
2401: while (ilink) {
2402: PetscCall(PetscStrcmp(ilink->splitname, splitname, &found));
2403: if (found) {
2404: *is = ilink->is;
2405: break;
2406: }
2407: ilink = ilink->next;
2408: }
2409: }
2410: PetscFunctionReturn(PETSC_SUCCESS);
2411: }
2413: /*@
2414: PCFieldSplitGetISByIndex - Retrieves the elements for a given split as an `IS`
2416: Logically Collective
2418: Input Parameters:
2419: + pc - the preconditioner context
2420: - index - index of this split
2422: Output Parameter:
2423: . is - the index set that defines the elements in this split
2425: Level: intermediate
2427: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitGetIS()`, `PCFieldSplitSetIS()`,
2429: @*/
2430: PetscErrorCode PCFieldSplitGetISByIndex(PC pc, PetscInt index, IS *is)
2431: {
2432: PetscFunctionBegin;
2433: PetscCheck(index >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", index);
2435: PetscAssertPointer(is, 3);
2436: {
2437: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2438: PC_FieldSplitLink ilink = jac->head;
2439: PetscInt i = 0;
2440: PetscCheck(index < jac->nsplits, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " requested but only %" PetscInt_FMT " exist", index, jac->nsplits);
2442: while (i < index) {
2443: ilink = ilink->next;
2444: ++i;
2445: }
2446: PetscCall(PCFieldSplitGetIS(pc, ilink->splitname, is));
2447: }
2448: PetscFunctionReturn(PETSC_SUCCESS);
2449: }
2451: /*@
2452: PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the
2453: fieldsplit preconditioner when calling `PCFieldSplitSetFields()`. If not set the matrix block size is used.
2455: Logically Collective
2457: Input Parameters:
2458: + pc - the preconditioner context
2459: - bs - the block size
2461: Level: intermediate
2463: Note:
2464: If the matrix is a `MATNEST` then the `is_rows[]` passed to `MatCreateNest()` determines the fields.
2466: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2467: @*/
2468: PetscErrorCode PCFieldSplitSetBlockSize(PC pc, PetscInt bs)
2469: {
2470: PetscFunctionBegin;
2473: PetscTryMethod(pc, "PCFieldSplitSetBlockSize_C", (PC, PetscInt), (pc, bs));
2474: PetscFunctionReturn(PETSC_SUCCESS);
2475: }
2477: /*@C
2478: PCFieldSplitGetSubKSP - Gets the `KSP` contexts for all splits
2480: Collective
2482: Input Parameter:
2483: . pc - the preconditioner context
2485: Output Parameters:
2486: + n - the number of splits
2487: - subksp - the array of `KSP` contexts
2489: Level: advanced
2491: Notes:
2492: After `PCFieldSplitGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2493: (not the `KSP`, just the array that contains them).
2495: You must call `PCSetUp()` before calling `PCFieldSplitGetSubKSP()`.
2497: If the fieldsplit is of type `PC_COMPOSITE_SCHUR`, it returns the `KSP` object used inside the
2498: Schur complement and the `KSP` object used to iterate over the Schur complement.
2499: To access all the `KSP` objects used in `PC_COMPOSITE_SCHUR`, use `PCFieldSplitSchurGetSubKSP()`.
2501: If the fieldsplit is of type `PC_COMPOSITE_GKB`, it returns the `KSP` object used to solve the
2502: inner linear system defined by the matrix H in each loop.
2504: Fortran Note:
2505: Call `PCFieldSplitRestoreSubKSP()` when the array of `KSP` is no longer needed
2507: Developer Notes:
2508: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2510: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitSchurGetSubKSP()`
2511: @*/
2512: PetscErrorCode PCFieldSplitGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2513: {
2514: PetscFunctionBegin;
2516: if (n) PetscAssertPointer(n, 2);
2517: PetscUseMethod(pc, "PCFieldSplitGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2518: PetscFunctionReturn(PETSC_SUCCESS);
2519: }
2521: /*@C
2522: PCFieldSplitSchurGetSubKSP - Gets the `KSP` contexts used inside the Schur complement based `PCFIELDSPLIT`
2524: Collective
2526: Input Parameter:
2527: . pc - the preconditioner context
2529: Output Parameters:
2530: + n - the number of splits
2531: - subksp - the array of `KSP` contexts
2533: Level: advanced
2535: Notes:
2536: After `PCFieldSplitSchurGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2537: (not the `KSP` just the array that contains them).
2539: You must call `PCSetUp()` before calling `PCFieldSplitSchurGetSubKSP()`.
2541: If the fieldsplit type is of type `PC_COMPOSITE_SCHUR`, it returns (in order)
2542: + 1 - the `KSP` used for the (1,1) block
2543: . 2 - the `KSP` used for the Schur complement (not the one used for the interior Schur solver)
2544: - 3 - the `KSP` used for the (1,1) block in the upper triangular factor (if different from that of the (1,1) block).
2546: It returns a null array if the fieldsplit is not of type `PC_COMPOSITE_SCHUR`; in this case, you should use `PCFieldSplitGetSubKSP()`.
2548: Fortran Note:
2549: Call `PCFieldSplitSchurRestoreSubKSP()` when the array of `KSP` is no longer needed
2551: Developer Notes:
2552: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2554: Should the functionality of `PCFieldSplitSchurGetSubKSP()` and `PCFieldSplitGetSubKSP()` be merged?
2556: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitGetSubKSP()`
2557: @*/
2558: PetscErrorCode PCFieldSplitSchurGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2559: {
2560: PetscFunctionBegin;
2562: if (n) PetscAssertPointer(n, 2);
2563: PetscUseMethod(pc, "PCFieldSplitSchurGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2564: PetscFunctionReturn(PETSC_SUCCESS);
2565: }
2567: /*@
2568: PCFieldSplitSetSchurPre - Indicates from what operator the preconditioner is constructed for the Schur complement.
2569: The default is the A11 matrix.
2571: Collective
2573: Input Parameters:
2574: + pc - the preconditioner context
2575: . ptype - which matrix to use for preconditioning the Schur complement: `PC_FIELDSPLIT_SCHUR_PRE_A11` (default),
2576: `PC_FIELDSPLIT_SCHUR_PRE_SELF`, `PC_FIELDSPLIT_SCHUR_PRE_USER`,
2577: `PC_FIELDSPLIT_SCHUR_PRE_SELFP`, and `PC_FIELDSPLIT_SCHUR_PRE_FULL`
2578: - pre - matrix to use for preconditioning, or `NULL`
2580: Options Database Keys:
2581: + -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is `a11`. See notes for meaning of various arguments
2582: - -fieldsplit_1_pc_type <pctype> - the preconditioner algorithm that is used to construct the preconditioner from the operator
2584: Level: intermediate
2586: Notes:
2587: If ptype is
2588: + a11 - the preconditioner for the Schur complement is generated from the block diagonal part of the preconditioner
2589: matrix associated with the Schur complement (i.e. A11), not the Schur complement matrix
2590: . self - the preconditioner for the Schur complement is generated from the symbolic representation of the Schur complement matrix:
2591: The only preconditioners that currently work with this symbolic representation matrix object are `PCLSC` and `PCHPDDM`
2592: . user - the preconditioner for the Schur complement is generated from the user provided matrix (pre argument
2593: to this function).
2594: . selfp - the preconditioning for the Schur complement is generated from an explicitly-assembled approximation $ Sp = A11 - A10 inv(diag(A00)) A01 $
2595: This is only a good preconditioner when diag(A00) is a good preconditioner for A00. Optionally, A00 can be
2596: lumped before extracting the diagonal using the additional option `-fieldsplit_1_mat_schur_complement_ainv_type lump`
2597: - full - the preconditioner for the Schur complement is generated from the exact Schur complement matrix representation
2598: computed internally by `PCFIELDSPLIT` (this is expensive)
2599: useful mostly as a test that the Schur complement approach can work for your problem
2601: When solving a saddle point problem, where the A11 block is identically zero, using `a11` as the ptype only makes sense
2602: with the additional option `-fieldsplit_1_pc_type none`. Usually for saddle point problems one would use a `ptype` of `self` and
2603: `-fieldsplit_1_pc_type lsc` which uses the least squares commutator to compute a preconditioner for the Schur complement.
2605: Developer Note:
2606: The name of this function and the option `-pc_fieldsplit_schur_precondition` are inconsistent; precondition should be used everywhere.
2608: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`,
2609: `MatSchurComplementSetAinvType()`, `PCLSC`, `PCFieldSplitSetSchurFactType()`
2610: @*/
2611: PetscErrorCode PCFieldSplitSetSchurPre(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2612: {
2613: PetscFunctionBegin;
2615: PetscTryMethod(pc, "PCFieldSplitSetSchurPre_C", (PC, PCFieldSplitSchurPreType, Mat), (pc, ptype, pre));
2616: PetscFunctionReturn(PETSC_SUCCESS);
2617: }
2619: PetscErrorCode PCFieldSplitSchurPrecondition(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2620: {
2621: return PCFieldSplitSetSchurPre(pc, ptype, pre);
2622: } /* Deprecated name */
2624: /*@
2625: PCFieldSplitGetSchurPre - For Schur complement fieldsplit, determine how the Schur complement will be
2626: preconditioned. See `PCFieldSplitSetSchurPre()` for details.
2628: Logically Collective
2630: Input Parameter:
2631: . pc - the preconditioner context
2633: Output Parameters:
2634: + 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`
2635: - pre - matrix to use for preconditioning (with `PC_FIELDSPLIT_SCHUR_PRE_USER`), or `NULL`
2637: Level: intermediate
2639: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCLSC`
2640: @*/
2641: PetscErrorCode PCFieldSplitGetSchurPre(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2642: {
2643: PetscFunctionBegin;
2645: PetscUseMethod(pc, "PCFieldSplitGetSchurPre_C", (PC, PCFieldSplitSchurPreType *, Mat *), (pc, ptype, pre));
2646: PetscFunctionReturn(PETSC_SUCCESS);
2647: }
2649: /*@
2650: PCFieldSplitSchurGetS - extract the `MATSCHURCOMPLEMENT` object used by this `PCFIELDSPLIT` in case it needs to be configured separately
2652: Not Collective
2654: Input Parameter:
2655: . pc - the preconditioner context
2657: Output Parameter:
2658: . S - the Schur complement matrix
2660: Level: advanced
2662: Note:
2663: This matrix should not be destroyed using `MatDestroy()`; rather, use `PCFieldSplitSchurRestoreS()`.
2665: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MATSCHURCOMPLEMENT`, `PCFieldSplitSchurRestoreS()`,
2666: `MatCreateSchurComplement()`, `MatSchurComplementGetKSP()`, `MatSchurComplementComputeExplicitOperator()`, `MatGetSchurComplement()`
2667: @*/
2668: PetscErrorCode PCFieldSplitSchurGetS(PC pc, Mat *S)
2669: {
2670: const char *t;
2671: PetscBool isfs;
2672: PC_FieldSplit *jac;
2674: PetscFunctionBegin;
2676: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2677: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2678: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2679: jac = (PC_FieldSplit *)pc->data;
2680: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2681: if (S) *S = jac->schur;
2682: PetscFunctionReturn(PETSC_SUCCESS);
2683: }
2685: /*@
2686: PCFieldSplitSchurRestoreS - returns the `MATSCHURCOMPLEMENT` matrix used by this `PC`
2688: Not Collective
2690: Input Parameters:
2691: + pc - the preconditioner context
2692: - S - the Schur complement matrix
2694: Level: advanced
2696: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MatSchurComplement`, `PCFieldSplitSchurGetS()`
2697: @*/
2698: PetscErrorCode PCFieldSplitSchurRestoreS(PC pc, Mat *S)
2699: {
2700: const char *t;
2701: PetscBool isfs;
2702: PC_FieldSplit *jac;
2704: PetscFunctionBegin;
2706: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2707: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2708: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2709: jac = (PC_FieldSplit *)pc->data;
2710: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2711: PetscCheck(S && (*S == jac->schur), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MatSchurComplement restored is not the same as gotten");
2712: PetscFunctionReturn(PETSC_SUCCESS);
2713: }
2715: static PetscErrorCode PCFieldSplitSetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2716: {
2717: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2719: PetscFunctionBegin;
2720: jac->schurpre = ptype;
2721: if (ptype == PC_FIELDSPLIT_SCHUR_PRE_USER && pre) {
2722: PetscCall(MatDestroy(&jac->schur_user));
2723: jac->schur_user = pre;
2724: PetscCall(PetscObjectReference((PetscObject)jac->schur_user));
2725: }
2726: PetscFunctionReturn(PETSC_SUCCESS);
2727: }
2729: static PetscErrorCode PCFieldSplitGetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2730: {
2731: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2733: PetscFunctionBegin;
2734: if (ptype) *ptype = jac->schurpre;
2735: if (pre) *pre = jac->schur_user;
2736: PetscFunctionReturn(PETSC_SUCCESS);
2737: }
2739: /*@
2740: PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain in the preconditioner {cite}`murphy2000note` and {cite}`ipsen2001note`
2742: Collective
2744: Input Parameters:
2745: + pc - the preconditioner context
2746: - ftype - which blocks of factorization to retain, `PC_FIELDSPLIT_SCHUR_FACT_FULL` is default
2748: Options Database Key:
2749: . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> - default is `full`
2751: Level: intermediate
2753: Notes:
2754: The `full` factorization is
2756: ```{math}
2757: \left(\begin{array}{cc} A & B \\
2758: C & E \\
2759: \end{array}\right) =
2760: \left(\begin{array}{cc} I & 0 \\
2761: C A^{-1} & I \\
2762: \end{array}\right)
2763: \left(\begin{array}{cc} A & 0 \\
2764: 0 & S \\
2765: \end{array}\right)
2766: \left(\begin{array}{cc} I & A^{-1}B \\
2767: 0 & I \\
2768: \end{array}\right) = L D U,
2769: ```
2771: 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 $LD$,
2772: and `diag` is the diagonal part with the sign of $S$ flipped (because this makes the preconditioner positive definite for many formulations,
2773: thus allowing the use of `KSPMINRES)`. Sign flipping of $S$ can be turned off with `PCFieldSplitSetSchurScale()`.
2775: If $A$ and $S$ are solved exactly
2776: + 1 - `full` factorization is a direct solver.
2777: . 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.
2778: - 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.
2780: If the iteration count is very low, consider using `KSPFGMRES` or `KSPGCR` which can use one less preconditioner
2781: application in this case. Note that the preconditioned operator may be highly non-normal, so such fast convergence may not be observed in practice.
2783: For symmetric problems in which $A$ is positive definite and $S$ is negative definite, `diag` can be used with `KSPMINRES`.
2785: 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 $S$).
2787: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurScale()`,
2788: [](sec_flexibleksp), `PCFieldSplitSetSchurPre()`
2789: @*/
2790: PetscErrorCode PCFieldSplitSetSchurFactType(PC pc, PCFieldSplitSchurFactType ftype)
2791: {
2792: PetscFunctionBegin;
2794: PetscTryMethod(pc, "PCFieldSplitSetSchurFactType_C", (PC, PCFieldSplitSchurFactType), (pc, ftype));
2795: PetscFunctionReturn(PETSC_SUCCESS);
2796: }
2798: static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc, PCFieldSplitSchurFactType ftype)
2799: {
2800: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2802: PetscFunctionBegin;
2803: jac->schurfactorization = ftype;
2804: PetscFunctionReturn(PETSC_SUCCESS);
2805: }
2807: /*@
2808: PCFieldSplitSetSchurScale - Controls the sign flip of S for `PC_FIELDSPLIT_SCHUR_FACT_DIAG`.
2810: Collective
2812: Input Parameters:
2813: + pc - the preconditioner context
2814: - scale - scaling factor for the Schur complement
2816: Options Database Key:
2817: . -pc_fieldsplit_schur_scale <scale> - default is -1.0
2819: Level: intermediate
2821: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurFactType`, `PCFieldSplitSetSchurFactType()`
2822: @*/
2823: PetscErrorCode PCFieldSplitSetSchurScale(PC pc, PetscScalar scale)
2824: {
2825: PetscFunctionBegin;
2828: PetscTryMethod(pc, "PCFieldSplitSetSchurScale_C", (PC, PetscScalar), (pc, scale));
2829: PetscFunctionReturn(PETSC_SUCCESS);
2830: }
2832: static PetscErrorCode PCFieldSplitSetSchurScale_FieldSplit(PC pc, PetscScalar scale)
2833: {
2834: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2836: PetscFunctionBegin;
2837: jac->schurscale = scale;
2838: PetscFunctionReturn(PETSC_SUCCESS);
2839: }
2841: /*@C
2842: PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement
2844: Collective
2846: Input Parameter:
2847: . pc - the preconditioner context
2849: Output Parameters:
2850: + A00 - the (0,0) block
2851: . A01 - the (0,1) block
2852: . A10 - the (1,0) block
2853: - A11 - the (1,1) block
2855: Level: advanced
2857: Note:
2858: Use `NULL` for any unneeded output arguments
2860: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `MatSchurComplementGetSubMatrices()`, `MatSchurComplementSetSubMatrices()`
2861: @*/
2862: PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc, Mat *A00, Mat *A01, Mat *A10, Mat *A11)
2863: {
2864: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2866: PetscFunctionBegin;
2868: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach.");
2869: if (A00) *A00 = jac->pmat[0];
2870: if (A01) *A01 = jac->B;
2871: if (A10) *A10 = jac->C;
2872: if (A11) *A11 = jac->pmat[1];
2873: PetscFunctionReturn(PETSC_SUCCESS);
2874: }
2876: /*@
2877: PCFieldSplitSetGKBTol - Sets the solver tolerance for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
2879: Collective
2881: Input Parameters:
2882: + pc - the preconditioner context
2883: - tolerance - the solver tolerance
2885: Options Database Key:
2886: . -pc_fieldsplit_gkb_tol <tolerance> - default is 1e-5
2888: Level: intermediate
2890: Note:
2891: The generalized GKB algorithm {cite}`arioli2013` uses a lower bound estimate of the error in energy norm as stopping criterion.
2892: It stops once the lower bound estimate undershoots the required solver tolerance. Although the actual error might be bigger than
2893: this estimate, the stopping criterion is satisfactory in practical cases.
2895: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBMaxit()`
2896: @*/
2897: PetscErrorCode PCFieldSplitSetGKBTol(PC pc, PetscReal tolerance)
2898: {
2899: PetscFunctionBegin;
2902: PetscTryMethod(pc, "PCFieldSplitSetGKBTol_C", (PC, PetscReal), (pc, tolerance));
2903: PetscFunctionReturn(PETSC_SUCCESS);
2904: }
2906: static PetscErrorCode PCFieldSplitSetGKBTol_FieldSplit(PC pc, PetscReal tolerance)
2907: {
2908: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2910: PetscFunctionBegin;
2911: jac->gkbtol = tolerance;
2912: PetscFunctionReturn(PETSC_SUCCESS);
2913: }
2915: /*@
2916: PCFieldSplitSetGKBMaxit - Sets the maximum number of iterations for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
2918: Collective
2920: Input Parameters:
2921: + pc - the preconditioner context
2922: - maxit - the maximum number of iterations
2924: Options Database Key:
2925: . -pc_fieldsplit_gkb_maxit <maxit> - default is 100
2927: Level: intermediate
2929: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBNu()`
2930: @*/
2931: PetscErrorCode PCFieldSplitSetGKBMaxit(PC pc, PetscInt maxit)
2932: {
2933: PetscFunctionBegin;
2936: PetscTryMethod(pc, "PCFieldSplitSetGKBMaxit_C", (PC, PetscInt), (pc, maxit));
2937: PetscFunctionReturn(PETSC_SUCCESS);
2938: }
2940: static PetscErrorCode PCFieldSplitSetGKBMaxit_FieldSplit(PC pc, PetscInt maxit)
2941: {
2942: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2944: PetscFunctionBegin;
2945: jac->gkbmaxit = maxit;
2946: PetscFunctionReturn(PETSC_SUCCESS);
2947: }
2949: /*@
2950: PCFieldSplitSetGKBDelay - Sets the delay in the lower bound error estimate in the generalized Golub-Kahan bidiagonalization {cite}`arioli2013` in `PCFIELDSPLIT`
2951: preconditioner.
2953: Collective
2955: Input Parameters:
2956: + pc - the preconditioner context
2957: - delay - the delay window in the lower bound estimate
2959: Options Database Key:
2960: . -pc_fieldsplit_gkb_delay <delay> - default is 5
2962: Level: intermediate
2964: Notes:
2965: 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 $
2966: is expressed as a truncated sum. The error at iteration k can only be measured at iteration (k + `delay`), and thus the algorithm needs
2967: at least (`delay` + 1) iterations to stop.
2969: For more details on the generalized Golub-Kahan bidiagonalization method and its lower bound stopping criterion, please refer to {cite}`arioli2013`
2971: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
2972: @*/
2973: PetscErrorCode PCFieldSplitSetGKBDelay(PC pc, PetscInt delay)
2974: {
2975: PetscFunctionBegin;
2978: PetscTryMethod(pc, "PCFieldSplitSetGKBDelay_C", (PC, PetscInt), (pc, delay));
2979: PetscFunctionReturn(PETSC_SUCCESS);
2980: }
2982: static PetscErrorCode PCFieldSplitSetGKBDelay_FieldSplit(PC pc, PetscInt delay)
2983: {
2984: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2986: PetscFunctionBegin;
2987: jac->gkbdelay = delay;
2988: PetscFunctionReturn(PETSC_SUCCESS);
2989: }
2991: /*@
2992: PCFieldSplitSetGKBNu - Sets the scalar value nu >= 0 in the transformation H = A00 + nu*A01*A01' of the (1,1) block in the
2993: Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
2995: Collective
2997: Input Parameters:
2998: + pc - the preconditioner context
2999: - nu - the shift parameter
3001: Options Database Key:
3002: . -pc_fieldsplit_gkb_nu <nu> - default is 1
3004: Level: intermediate
3006: Notes:
3007: 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,
3008: 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
3009: necessary to find a good balance in between the convergence of the inner and outer loop.
3011: 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.
3013: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
3014: @*/
3015: PetscErrorCode PCFieldSplitSetGKBNu(PC pc, PetscReal nu)
3016: {
3017: PetscFunctionBegin;
3020: PetscTryMethod(pc, "PCFieldSplitSetGKBNu_C", (PC, PetscReal), (pc, nu));
3021: PetscFunctionReturn(PETSC_SUCCESS);
3022: }
3024: static PetscErrorCode PCFieldSplitSetGKBNu_FieldSplit(PC pc, PetscReal nu)
3025: {
3026: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3028: PetscFunctionBegin;
3029: jac->gkbnu = nu;
3030: PetscFunctionReturn(PETSC_SUCCESS);
3031: }
3033: static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc, PCCompositeType type)
3034: {
3035: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3037: PetscFunctionBegin;
3038: jac->type = type;
3039: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
3040: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
3041: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
3042: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
3043: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
3044: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
3045: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
3046: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
3047: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
3049: if (type == PC_COMPOSITE_SCHUR) {
3050: pc->ops->apply = PCApply_FieldSplit_Schur;
3051: pc->ops->applytranspose = PCApplyTranspose_FieldSplit_Schur;
3052: pc->ops->view = PCView_FieldSplit_Schur;
3053: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_Schur;
3055: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit_Schur));
3056: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", PCFieldSplitSetSchurPre_FieldSplit));
3057: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", PCFieldSplitGetSchurPre_FieldSplit));
3058: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", PCFieldSplitSetSchurFactType_FieldSplit));
3059: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", PCFieldSplitSetSchurScale_FieldSplit));
3060: } else if (type == PC_COMPOSITE_GKB) {
3061: pc->ops->apply = PCApply_FieldSplit_GKB;
3062: pc->ops->applytranspose = NULL;
3063: pc->ops->view = PCView_FieldSplit_GKB;
3064: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_GKB;
3066: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3067: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", PCFieldSplitSetGKBTol_FieldSplit));
3068: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", PCFieldSplitSetGKBMaxit_FieldSplit));
3069: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", PCFieldSplitSetGKBNu_FieldSplit));
3070: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", PCFieldSplitSetGKBDelay_FieldSplit));
3071: } else {
3072: pc->ops->apply = PCApply_FieldSplit;
3073: pc->ops->applytranspose = PCApplyTranspose_FieldSplit;
3074: pc->ops->view = PCView_FieldSplit;
3075: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit;
3077: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3078: }
3079: PetscFunctionReturn(PETSC_SUCCESS);
3080: }
3082: static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc, PetscInt bs)
3083: {
3084: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3086: PetscFunctionBegin;
3087: PetscCheck(bs >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Blocksize must be positive, you gave %" PetscInt_FMT, bs);
3088: 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);
3089: jac->bs = bs;
3090: PetscFunctionReturn(PETSC_SUCCESS);
3091: }
3093: static PetscErrorCode PCSetCoordinates_FieldSplit(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[])
3094: {
3095: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3096: PC_FieldSplitLink ilink_current = jac->head;
3097: IS is_owned;
3099: PetscFunctionBegin;
3100: jac->coordinates_set = PETSC_TRUE; // Internal flag
3101: PetscCall(MatGetOwnershipIS(pc->mat, &is_owned, NULL));
3103: while (ilink_current) {
3104: // For each IS, embed it to get local coords indces
3105: IS is_coords;
3106: PetscInt ndofs_block;
3107: const PetscInt *block_dofs_enumeration; // Numbering of the dofs relevant to the current block
3109: // Setting drop to true for safety. It should make no difference.
3110: PetscCall(ISEmbed(ilink_current->is, is_owned, PETSC_TRUE, &is_coords));
3111: PetscCall(ISGetLocalSize(is_coords, &ndofs_block));
3112: PetscCall(ISGetIndices(is_coords, &block_dofs_enumeration));
3114: // Allocate coordinates vector and set it directly
3115: PetscCall(PetscMalloc1(ndofs_block * dim, &ilink_current->coords));
3116: for (PetscInt dof = 0; dof < ndofs_block; ++dof) {
3117: for (PetscInt d = 0; d < dim; ++d) (ilink_current->coords)[dim * dof + d] = coords[dim * block_dofs_enumeration[dof] + d];
3118: }
3119: ilink_current->dim = dim;
3120: ilink_current->ndofs = ndofs_block;
3121: PetscCall(ISRestoreIndices(is_coords, &block_dofs_enumeration));
3122: PetscCall(ISDestroy(&is_coords));
3123: ilink_current = ilink_current->next;
3124: }
3125: PetscCall(ISDestroy(&is_owned));
3126: PetscFunctionReturn(PETSC_SUCCESS);
3127: }
3129: /*@
3130: PCFieldSplitSetType - Sets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3132: Collective
3134: Input Parameters:
3135: + pc - the preconditioner context
3136: - type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`,
3137: `PC_COMPOSITE_GKB`
3139: Options Database Key:
3140: . -pc_fieldsplit_type <one of multiplicative, additive, symmetric_multiplicative, special, schur> - Sets fieldsplit preconditioner type
3142: Level: intermediate
3144: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCCompositeType`, `PCCompositeGetType()`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3145: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`, `PCFieldSplitSetSchurFactType()`
3146: @*/
3147: PetscErrorCode PCFieldSplitSetType(PC pc, PCCompositeType type)
3148: {
3149: PetscFunctionBegin;
3151: PetscTryMethod(pc, "PCFieldSplitSetType_C", (PC, PCCompositeType), (pc, type));
3152: PetscFunctionReturn(PETSC_SUCCESS);
3153: }
3155: /*@
3156: PCFieldSplitGetType - Gets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3158: Not collective
3160: Input Parameter:
3161: . pc - the preconditioner context
3163: Output Parameter:
3164: . type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3166: Level: intermediate
3168: .seealso: [](sec_block_matrices), `PC`, `PCCompositeSetType()`, `PCFIELDSPLIT`, `PCCompositeType`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3169: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3170: @*/
3171: PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type)
3172: {
3173: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3175: PetscFunctionBegin;
3177: PetscAssertPointer(type, 2);
3178: *type = jac->type;
3179: PetscFunctionReturn(PETSC_SUCCESS);
3180: }
3182: /*@
3183: PCFieldSplitSetDMSplits - Flags whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3185: Logically Collective
3187: Input Parameters:
3188: + pc - the preconditioner context
3189: - flg - boolean indicating whether to use field splits defined by the `DM`
3191: Options Database Key:
3192: . -pc_fieldsplit_dm_splits <bool> - use the field splits defined by the `DM`
3194: Level: intermediate
3196: Developer Note:
3197: The name should be `PCFieldSplitSetUseDMSplits()`, similar change to options database
3199: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3200: @*/
3201: PetscErrorCode PCFieldSplitSetDMSplits(PC pc, PetscBool flg)
3202: {
3203: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3204: PetscBool isfs;
3206: PetscFunctionBegin;
3209: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3210: if (isfs) jac->dm_splits = flg;
3211: PetscFunctionReturn(PETSC_SUCCESS);
3212: }
3214: /*@
3215: PCFieldSplitGetDMSplits - Returns flag indicating whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3217: Logically Collective
3219: Input Parameter:
3220: . pc - the preconditioner context
3222: Output Parameter:
3223: . flg - boolean indicating whether to use field splits defined by the `DM`
3225: Level: intermediate
3227: Developer Note:
3228: The name should be `PCFieldSplitGetUseDMSplits()`
3230: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3231: @*/
3232: PetscErrorCode PCFieldSplitGetDMSplits(PC pc, PetscBool *flg)
3233: {
3234: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3235: PetscBool isfs;
3237: PetscFunctionBegin;
3239: PetscAssertPointer(flg, 2);
3240: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3241: if (isfs) {
3242: if (flg) *flg = jac->dm_splits;
3243: }
3244: PetscFunctionReturn(PETSC_SUCCESS);
3245: }
3247: /*@
3248: PCFieldSplitGetDetectSaddlePoint - Returns flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3250: Logically Collective
3252: Input Parameter:
3253: . pc - the preconditioner context
3255: Output Parameter:
3256: . flg - boolean indicating whether to detect fields or not
3258: Level: intermediate
3260: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDetectSaddlePoint()`
3261: @*/
3262: PetscErrorCode PCFieldSplitGetDetectSaddlePoint(PC pc, PetscBool *flg)
3263: {
3264: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3266: PetscFunctionBegin;
3267: *flg = jac->detect;
3268: PetscFunctionReturn(PETSC_SUCCESS);
3269: }
3271: /*@
3272: PCFieldSplitSetDetectSaddlePoint - Sets flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3274: Logically Collective
3276: Input Parameter:
3277: . pc - the preconditioner context
3279: Output Parameter:
3280: . flg - boolean indicating whether to detect fields or not
3282: Options Database Key:
3283: . -pc_fieldsplit_detect_saddle_point <bool> - detect and use the saddle point
3285: Level: intermediate
3287: Note:
3288: Also sets the split type to `PC_COMPOSITE_SCHUR` (see `PCFieldSplitSetType()`) and the Schur preconditioner type to `PC_FIELDSPLIT_SCHUR_PRE_SELF` (see `PCFieldSplitSetSchurPre()`).
3290: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDetectSaddlePoint()`, `PCFieldSplitSetType()`, `PCFieldSplitSetSchurPre()`, `PC_FIELDSPLIT_SCHUR_PRE_SELF`
3291: @*/
3292: PetscErrorCode PCFieldSplitSetDetectSaddlePoint(PC pc, PetscBool flg)
3293: {
3294: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3296: PetscFunctionBegin;
3297: jac->detect = flg;
3298: if (jac->detect) {
3299: PetscCall(PCFieldSplitSetType(pc, PC_COMPOSITE_SCHUR));
3300: PetscCall(PCFieldSplitSetSchurPre(pc, PC_FIELDSPLIT_SCHUR_PRE_SELF, NULL));
3301: }
3302: PetscFunctionReturn(PETSC_SUCCESS);
3303: }
3305: /*MC
3306: PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual
3307: collections of variables (that may overlap) called fields or splits. Each field often represents a different continuum variable
3308: represented on a grid, such as velocity, pressure, or temperature.
3309: In the literature these are sometimes called block preconditioners; but should not be confused with `PCBJACOBI`.
3310: See [the users manual section on "Solving Block Matrices"](sec_block_matrices) for more details.
3312: Options Database Keys:
3313: + -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the `%d`'th split
3314: . -pc_fieldsplit_default - automatically add any fields to additional splits that have not
3315: been supplied explicitly by `-pc_fieldsplit_%d_fields`
3316: . -pc_fieldsplit_block_size <bs> - size of block that defines fields (i.e. there are bs fields)
3317: when the matrix is not of `MatType` `MATNEST`
3318: . -pc_fieldsplit_type <additive,multiplicative,symmetric_multiplicative,schur,gkb> - type of relaxation or factorization splitting
3319: . -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is `a11`; see `PCFieldSplitSetSchurPre()`
3320: . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> - set factorization type when using `-pc_fieldsplit_type schur`;
3321: see `PCFieldSplitSetSchurFactType()`
3322: . -pc_fieldsplit_dm_splits <true,false> (default is true) - Whether to use `DMCreateFieldDecomposition()` for splits
3323: - -pc_fieldsplit_detect_saddle_point - automatically finds rows with zero diagonal and uses Schur complement with no preconditioner as the solver
3325: Options prefixes for inner solvers when using the Schur complement preconditioner are `-fieldsplit_0_` and `-fieldsplit_1_` .
3326: The options prefix for the inner solver when using the Golub-Kahan biadiagonalization preconditioner is `-fieldsplit_0_`
3327: For all other solvers they are `-fieldsplit_%d_` for the `%d`'th field; use `-fieldsplit_` for all fields.
3329: To set options on the solvers for all blocks, prepend `-fieldsplit_` to all the `PC`
3330: options database keys. For example, `-fieldsplit_pc_type ilu` `-fieldsplit_pc_factor_levels 1`.
3332: To set the options on the solvers separate for each block call `PCFieldSplitGetSubKSP()`
3333: and set the options directly on the resulting `KSP` object
3335: Level: intermediate
3337: Notes:
3338: Use `PCFieldSplitSetFields()` to set splits defined by "strided" entries or with a `MATNEST` and `PCFieldSplitSetIS()`
3339: to define a split by an arbitrary collection of entries.
3341: If no splits are set, the default is used. If a `DM` is associated with the `PC` and it supports
3342: `DMCreateFieldDecomposition()`, then that is used for the default. Otherwise if the matrix is not `MATNEST`, the splits are defined by entries strided by bs,
3343: beginning at 0 then 1, etc to bs-1. The block size can be set with `PCFieldSplitSetBlockSize()`,
3344: if this is not called the block size defaults to the blocksize of the second matrix passed
3345: to `KSPSetOperators()`/`PCSetOperators()`.
3347: For the Schur complement preconditioner if
3348: ```{math}
3349: J = \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{10} & A_{11} \end{array}\right]
3350: ```
3352: the preconditioner using `full` factorization is logically
3353: ```{math}
3354: \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]
3355: ```
3356: where the action of $\text{ksp}(A_{00})$ is applied using the `KSP` solver with prefix `-fieldsplit_0_`. $S$ is the Schur complement
3357: ```{math}
3358: S = A_{11} - A_{10} \text{ksp}(A_{00}) A_{01}
3359: ```
3360: 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`
3361: 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
3362: 0th index, the `KSP` associated with `-fieldsplit_0_`, and at its 1st index, the `KSP` corresponding to `-fieldsplit_1_`.
3363: By default, $A_{11}$ is used to construct a preconditioner for $S$, use `PCFieldSplitSetSchurPre()` for all the possible ways to construct the preconditioner for $S$.
3365: The factorization type is set using `-pc_fieldsplit_schur_fact_type <diag, lower, upper, full>`. `full` is shown above,
3366: `diag` gives
3367: ```{math}
3368: \left[\begin{array}{cc} \text{ksp}(A_{00}) & 0 \\ 0 & -\text{ksp}(S) \end{array}\right]
3369: ```
3370: 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
3371: can be turned off with `PCFieldSplitSetSchurScale()` or by command line `-pc_fieldsplit_schur_scale 1.0`. The `lower` factorization is the inverse of
3372: ```{math}
3373: \left[\begin{array}{cc} A_{00} & 0 \\ A_{10} & S \end{array}\right]
3374: ```
3375: where the inverses of $A_{00}$ and $S$ are applied using `KSP`s. The upper factorization is the inverse of
3376: ```{math}
3377: \left[\begin{array}{cc} A_{00} & A_{01} \\ 0 & S \end{array}\right]
3378: ```
3379: where again the inverses of $A_{00}$ and $S$ are applied using `KSP`s.
3381: If only one set of indices (one `IS`) is provided with `PCFieldSplitSetIS()` then the complement of that `IS`
3382: is used automatically for a second submatrix.
3384: The fieldsplit preconditioner cannot currently be used with the `MATBAIJ` or `MATSBAIJ` data formats if the blocksize is larger than 1.
3385: Generally it should be used with the `MATAIJ` or `MATNEST` `MatType`
3387: The forms of these preconditioners are closely related, if not identical, to forms derived as "Distributive Iterations", see,
3388: for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling {cite}`wesseling2009`.
3389: One can also use `PCFIELDSPLIT` inside a smoother resulting in "Distributive Smoothers".
3391: See "A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations" {cite}`elman2008tcp`.
3393: The Constrained Pressure Preconditioner (CPR) can be implemented using `PCCOMPOSITE` with `PCGALERKIN`. CPR first solves an $R A P$ subsystem, updates the
3394: residual on all variables (`PCCompositeSetType(pc,PC_COMPOSITE_MULTIPLICATIVE)`), and then applies a simple ILU like preconditioner on all the variables.
3396: The generalized Golub-Kahan bidiagonalization preconditioner (GKB) can be applied to symmetric $2 \times 2$ block matrices of the shape
3397: ```{math}
3398: \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{01}' & 0 \end{array}\right]
3399: ```
3400: 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 $H = _{A00} + \nu*A_{01}*A_{01}'$.
3401: 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_`.
3403: Some `PCFIELDSPLIT` variants are called physics-based preconditioners, since the preconditioner takes into account the underlying physics of the
3404: problem. But this nomenclature is not well-defined.
3406: Developer Note:
3407: The Schur complement functionality of `PCFIELDSPLIT` should likely be factored into its own `PC` thus simplifying the implementation of the preconditioners and their
3408: user API.
3410: .seealso: [](sec_block_matrices), `PC`, `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCLSC`,
3411: `PCFieldSplitGetSubKSP()`, `PCFieldSplitSchurGetSubKSP()`, `PCFieldSplitSetFields()`,
3412: `PCFieldSplitSetType()`, `PCFieldSplitSetIS()`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitSetSchurFactType()`,
3413: `MatSchurComplementSetAinvType()`, `PCFieldSplitSetSchurScale()`, `PCFieldSplitSetDetectSaddlePoint()`
3414: M*/
3416: PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc)
3417: {
3418: PC_FieldSplit *jac;
3420: PetscFunctionBegin;
3421: PetscCall(PetscNew(&jac));
3423: jac->bs = -1;
3424: jac->type = PC_COMPOSITE_MULTIPLICATIVE;
3425: jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */
3426: jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL;
3427: jac->schurscale = -1.0;
3428: jac->dm_splits = PETSC_TRUE;
3429: jac->gkbtol = 1e-5;
3430: jac->gkbdelay = 5;
3431: jac->gkbnu = 1;
3432: jac->gkbmaxit = 100;
3434: pc->data = (void *)jac;
3436: pc->ops->setup = PCSetUp_FieldSplit;
3437: pc->ops->reset = PCReset_FieldSplit;
3438: pc->ops->destroy = PCDestroy_FieldSplit;
3439: pc->ops->setfromoptions = PCSetFromOptions_FieldSplit;
3440: pc->ops->applyrichardson = NULL;
3442: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", PCFieldSplitSchurGetSubKSP_FieldSplit));
3443: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", PCFieldSplitSetFields_FieldSplit));
3444: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", PCFieldSplitSetIS_FieldSplit));
3445: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", PCFieldSplitSetType_FieldSplit));
3446: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", PCFieldSplitSetBlockSize_FieldSplit));
3447: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", PCFieldSplitRestrictIS_FieldSplit));
3448: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", PCSetCoordinates_FieldSplit));
3450: /* Initialize function pointers */
3451: PetscCall(PCFieldSplitSetType(pc, jac->type));
3452: PetscFunctionReturn(PETSC_SUCCESS);
3453: }