Actual source code: fieldsplit.c
1: #include <petsc/private/pcimpl.h>
2: #include <petsc/private/kspimpl.h>
3: #include <petsc/private/matimpl.h>
4: #include <petscdm.h>
5: #include <petscdevice.h>
6: #if PetscDefined(HAVE_CUDA)
7: #include <petscdevice_cuda.h>
8: #endif
9: #if PetscDefined(HAVE_HIP)
10: #include <petscdevice_hip.h>
11: #endif
13: const char *const PCFieldSplitSchurPreTypes[] = {"SELF", "SELFP", "A11", "USER", "FULL", "PCFieldSplitSchurPreType", "PC_FIELDSPLIT_SCHUR_PRE_", NULL};
14: const char *const PCFieldSplitSchurFactTypes[] = {"DIAG", "LOWER", "UPPER", "FULL", "PCFieldSplitSchurFactType", "PC_FIELDSPLIT_SCHUR_FACT_", NULL};
16: 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;
18: typedef struct _PC_FieldSplitLink *PC_FieldSplitLink;
19: struct _PC_FieldSplitLink {
20: KSP ksp;
21: Vec x, y, z;
22: Mat X, Y, Z;
23: char *splitname;
24: PetscInt nfields;
25: PetscInt *fields, *fields_col;
26: VecScatter sctx;
27: IS is, is_col;
28: PC_FieldSplitLink next, previous;
29: PetscLogEvent event;
31: /* Used only when setting coordinates with PCSetCoordinates */
32: PetscInt dim;
33: PetscInt ndofs;
34: PetscReal *coords;
35: };
37: typedef struct {
38: PCCompositeType type;
39: PetscBool defaultsplit; /* Flag for a system with a set of 'k' scalar fields with the same layout (and bs = k) */
40: PetscBool splitdefined; /* Flag is set after the splits have been defined, to prevent more splits from being added */
41: PetscInt bs; /* Block size for IS and Mat structures */
42: PetscInt nsplits; /* Number of field divisions defined */
43: Vec *x, *y, w1, w2;
44: Mat *mat; /* The diagonal block for each split */
45: Mat *pmat; /* The preconditioning diagonal block for each split */
46: Mat *Afield; /* The rows of the matrix associated with each split */
47: PetscBool issetup;
49: /* Only used when Schur complement preconditioning is used */
50: Mat B; /* The (0,1) block */
51: Mat C; /* The (1,0) block */
52: Mat schur; /* The Schur complement S = A11 - A10 A00^{-1} A01, the KSP here, kspinner, is H_1 in [El08] */
53: Mat schurp; /* Assembled approximation to S built by MatSchurComplement to be used as a matrix for constructing the preconditioner when solving with S */
54: Mat schur_user; /* User-provided matrix for constructing the preconditioner for the Schur complement */
55: PCFieldSplitSchurPreType schurpre; /* Determines which matrix is used for the Schur complement */
56: PCFieldSplitSchurFactType schurfactorization;
57: KSP kspschur; /* The solver for S */
58: KSP kspupper; /* The solver for A in the upper diagonal part of the factorization (H_2 in [El08]) */
59: PetscScalar schurscale; /* Scaling factor for the Schur complement solution with DIAG factorization */
61: /* Only used when Golub-Kahan bidiagonalization preconditioning is used */
62: Mat H; /* The modified matrix H = A00 + nu*A01*A01' */
63: PetscReal gkbtol; /* Stopping tolerance for lower bound estimate */
64: PetscInt gkbdelay; /* The delay window for the stopping criterion */
65: PetscReal gkbnu; /* Parameter for augmented Lagrangian H = A + nu*A01*A01' */
66: PetscInt gkbmaxit; /* Maximum number of iterations for outer loop */
67: PetscBool gkbmonitor; /* Monitor for gkb iterations and the lower bound error */
68: PetscViewer gkbviewer; /* Viewer context for gkbmonitor */
69: Vec u, v, d, Hu; /* Work vectors for the GKB algorithm */
70: PetscScalar *vecz; /* Contains intermediate values, eg for lower bound */
72: PC_FieldSplitLink head;
73: PetscBool isrestrict; /* indicates PCFieldSplitRestrictIS() has been last called on this object, hack */
74: PetscBool suboptionsset; /* Indicates that the KSPSetFromOptions() has been called on the sub-KSPs */
75: PetscBool dm_splits; /* Whether to use DMCreateFieldDecomposition() whenever possible */
76: PetscBool diag_use_amat; /* Whether to extract diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */
77: PetscBool offdiag_use_amat; /* Whether to extract off-diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */
78: PetscBool detect; /* Whether to form 2-way split by finding zero diagonal entries */
79: PetscBool coordinates_set; /* Whether PCSetCoordinates has been called */
80: } PC_FieldSplit;
82: /*
83: Note:
84: there is no particular reason that pmat, x, and y are stored as arrays in PC_FieldSplit instead of
85: inside PC_FieldSplitLink, just historical. If you want to be able to add new fields after already using the
86: PC you could change this.
87: */
89: /* This helper is so that setting a user-provided matrix is orthogonal to choosing to use it. This way the
90: * application-provided FormJacobian can provide this matrix without interfering with the user's (command-line) choices. */
91: static Mat FieldSplitSchurPre(PC_FieldSplit *jac)
92: {
93: switch (jac->schurpre) {
94: case PC_FIELDSPLIT_SCHUR_PRE_SELF:
95: return jac->schur;
96: case PC_FIELDSPLIT_SCHUR_PRE_SELFP:
97: return jac->schurp;
98: case PC_FIELDSPLIT_SCHUR_PRE_A11:
99: return jac->pmat[1];
100: case PC_FIELDSPLIT_SCHUR_PRE_FULL: /* We calculate this and store it in schur_user */
101: case PC_FIELDSPLIT_SCHUR_PRE_USER: /* Use a user-provided matrix if it is given, otherwise diagonal block */
102: default:
103: return jac->schur_user ? jac->schur_user : jac->pmat[1];
104: }
105: }
107: #include <petscdraw.h>
108: static PetscErrorCode PCView_FieldSplit(PC pc, PetscViewer viewer)
109: {
110: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
111: PetscBool isascii, isdraw;
112: PetscInt i, j;
113: PC_FieldSplitLink ilink = jac->head;
115: PetscFunctionBegin;
116: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
117: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
118: if (isascii) {
119: if (jac->bs > 0) {
120: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT ", blocksize = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits, jac->bs));
121: } else {
122: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits));
123: }
124: if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n"));
125: if (jac->diag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for diagonal blocks\n"));
126: if (jac->offdiag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for off-diagonal blocks\n"));
127: PetscCall(PetscViewerASCIIPrintf(viewer, " Solver info for each split is in the following KSP objects:\n"));
128: for (i = 0; i < jac->nsplits; i++) {
129: if (ilink->fields) {
130: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Fields ", i));
131: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
132: for (j = 0; j < ilink->nfields; j++) {
133: if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ","));
134: PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j]));
135: }
136: PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
137: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
138: } else {
139: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Defined by IS\n", i));
140: }
141: PetscCall(KSPView(ilink->ksp, viewer));
142: ilink = ilink->next;
143: }
144: }
146: if (isdraw) {
147: PetscDraw draw;
148: PetscReal x, y, w, wd;
150: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
151: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
152: w = 2 * PetscMin(1.0 - x, x);
153: wd = w / (jac->nsplits + 1);
154: x = x - wd * (jac->nsplits - 1) / 2.0;
155: for (i = 0; i < jac->nsplits; i++) {
156: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
157: PetscCall(KSPView(ilink->ksp, viewer));
158: PetscCall(PetscDrawPopCurrentPoint(draw));
159: x += wd;
160: ilink = ilink->next;
161: }
162: }
163: PetscFunctionReturn(PETSC_SUCCESS);
164: }
166: static PetscErrorCode PCView_FieldSplit_Schur(PC pc, PetscViewer viewer)
167: {
168: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
169: PetscBool isascii, isdraw;
170: PetscInt i, j;
171: PC_FieldSplitLink ilink = jac->head;
172: MatSchurComplementAinvType atype;
174: PetscFunctionBegin;
175: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
176: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
177: if (isascii) {
178: if (jac->bs > 0) {
179: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with Schur preconditioner, blocksize = %" PetscInt_FMT ", factorization %s\n", jac->bs, PCFieldSplitSchurFactTypes[jac->schurfactorization]));
180: } else {
181: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with Schur preconditioner, factorization %s\n", PCFieldSplitSchurFactTypes[jac->schurfactorization]));
182: }
183: if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n"));
184: switch (jac->schurpre) {
185: case PC_FIELDSPLIT_SCHUR_PRE_SELF:
186: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from S itself\n"));
187: break;
188: case PC_FIELDSPLIT_SCHUR_PRE_SELFP:
189: if (jac->schur) {
190: PetscCall(MatSchurComplementGetAinvType(jac->schur, &atype));
191: 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 "))));
192: }
193: break;
194: case PC_FIELDSPLIT_SCHUR_PRE_A11:
195: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from A11\n"));
196: break;
197: case PC_FIELDSPLIT_SCHUR_PRE_FULL:
198: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from the exact Schur complement\n"));
199: break;
200: case PC_FIELDSPLIT_SCHUR_PRE_USER:
201: if (jac->schur_user) {
202: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from user provided matrix\n"));
203: } else {
204: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioner for the Schur complement formed from A11\n"));
205: }
206: break;
207: default:
208: SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Invalid Schur preconditioning type: %d", jac->schurpre);
209: }
210: PetscCall(PetscViewerASCIIPrintf(viewer, " Split info:\n"));
211: PetscCall(PetscViewerASCIIPushTab(viewer));
212: for (i = 0; i < jac->nsplits; i++) {
213: if (ilink->fields) {
214: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Fields ", i));
215: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
216: for (j = 0; j < ilink->nfields; j++) {
217: if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ","));
218: PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j]));
219: }
220: PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
221: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
222: } else {
223: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number %" PetscInt_FMT " Defined by IS\n", i));
224: }
225: ilink = ilink->next;
226: }
227: PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for A00 block\n"));
228: PetscCall(PetscViewerASCIIPushTab(viewer));
229: if (jac->head) PetscCall(KSPView(jac->head->ksp, viewer));
230: else PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n"));
231: PetscCall(PetscViewerASCIIPopTab(viewer));
232: if (jac->head && jac->kspupper != jac->head->ksp) {
233: PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for upper A00 in upper triangular factor\n"));
234: PetscCall(PetscViewerASCIIPushTab(viewer));
235: if (jac->kspupper) PetscCall(KSPView(jac->kspupper, viewer));
236: else PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n"));
237: PetscCall(PetscViewerASCIIPopTab(viewer));
238: }
239: PetscCall(PetscViewerASCIIPrintf(viewer, "KSP solver for S = A11 - A10 inv(A00) A01\n"));
240: PetscCall(PetscViewerASCIIPushTab(viewer));
241: if (jac->kspschur) {
242: PetscCall(KSPView(jac->kspschur, viewer));
243: } else {
244: PetscCall(PetscViewerASCIIPrintf(viewer, " not yet available\n"));
245: }
246: PetscCall(PetscViewerASCIIPopTab(viewer));
247: PetscCall(PetscViewerASCIIPopTab(viewer));
248: } else if (isdraw && jac->head) {
249: PetscDraw draw;
250: PetscReal x, y, w, wd, h;
251: PetscInt cnt = 2;
252: char str[32];
254: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
255: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
256: if (jac->kspupper != jac->head->ksp) cnt++;
257: w = 2 * PetscMin(1.0 - x, x);
258: wd = w / (cnt + 1);
260: PetscCall(PetscSNPrintf(str, 32, "Schur fact. %s", PCFieldSplitSchurFactTypes[jac->schurfactorization]));
261: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_RED, PETSC_DRAW_BLACK, str, NULL, &h));
262: y -= h;
263: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_USER && !jac->schur_user) {
264: PetscCall(PetscSNPrintf(str, 32, "Prec. for Schur from %s", PCFieldSplitSchurPreTypes[PC_FIELDSPLIT_SCHUR_PRE_A11]));
265: } else {
266: PetscCall(PetscSNPrintf(str, 32, "Prec. for Schur from %s", PCFieldSplitSchurPreTypes[jac->schurpre]));
267: }
268: PetscCall(PetscDrawStringBoxed(draw, x + wd * (cnt - 1) / 2.0, y, PETSC_DRAW_RED, PETSC_DRAW_BLACK, str, NULL, &h));
269: y -= h;
270: x = x - wd * (cnt - 1) / 2.0;
272: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
273: PetscCall(KSPView(jac->head->ksp, viewer));
274: PetscCall(PetscDrawPopCurrentPoint(draw));
275: if (jac->kspupper != jac->head->ksp) {
276: x += wd;
277: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
278: PetscCall(KSPView(jac->kspupper, viewer));
279: PetscCall(PetscDrawPopCurrentPoint(draw));
280: }
281: x += wd;
282: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
283: PetscCall(KSPView(jac->kspschur, viewer));
284: PetscCall(PetscDrawPopCurrentPoint(draw));
285: }
286: PetscFunctionReturn(PETSC_SUCCESS);
287: }
289: static PetscErrorCode PCView_FieldSplit_GKB(PC pc, PetscViewer viewer)
290: {
291: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
292: PetscBool isascii, isdraw;
293: PetscInt i, j;
294: PC_FieldSplitLink ilink = jac->head;
296: PetscFunctionBegin;
297: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
298: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
299: if (isascii) {
300: if (jac->bs > 0) {
301: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT ", blocksize = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits, jac->bs));
302: } else {
303: PetscCall(PetscViewerASCIIPrintf(viewer, " FieldSplit with %s composition: total splits = %" PetscInt_FMT "\n", PCCompositeTypes[jac->type], jac->nsplits));
304: }
305: if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for blocks\n"));
306: if (jac->diag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for diagonal blocks\n"));
307: if (jac->offdiag_use_amat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat (not Pmat) as operator for off-diagonal blocks\n"));
309: PetscCall(PetscViewerASCIIPrintf(viewer, " Stopping tolerance=%.1e, delay in error estimate=%" PetscInt_FMT ", maximum iterations=%" PetscInt_FMT "\n", (double)jac->gkbtol, jac->gkbdelay, jac->gkbmaxit));
310: PetscCall(PetscViewerASCIIPrintf(viewer, " Solver info for H = A00 + nu*A01*A01' matrix:\n"));
311: PetscCall(PetscViewerASCIIPushTab(viewer));
313: if (ilink->fields) {
314: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number 0 Fields "));
315: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
316: for (j = 0; j < ilink->nfields; j++) {
317: if (j > 0) PetscCall(PetscViewerASCIIPrintf(viewer, ","));
318: PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT, ilink->fields[j]));
319: }
320: PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
321: PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
322: } else {
323: PetscCall(PetscViewerASCIIPrintf(viewer, "Split number 0 Defined by IS\n"));
324: }
325: PetscCall(KSPView(ilink->ksp, viewer));
327: PetscCall(PetscViewerASCIIPopTab(viewer));
328: }
330: if (isdraw) {
331: PetscDraw draw;
332: PetscReal x, y, w, wd;
334: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
335: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
336: w = 2 * PetscMin(1.0 - x, x);
337: wd = w / (jac->nsplits + 1);
338: x = x - wd * (jac->nsplits - 1) / 2.0;
339: for (i = 0; i < jac->nsplits; i++) {
340: PetscCall(PetscDrawPushCurrentPoint(draw, x, y));
341: PetscCall(KSPView(ilink->ksp, viewer));
342: PetscCall(PetscDrawPopCurrentPoint(draw));
343: x += wd;
344: ilink = ilink->next;
345: }
346: }
347: PetscFunctionReturn(PETSC_SUCCESS);
348: }
350: /* Precondition: jac->bs is set to a meaningful value or MATNEST */
351: static PetscErrorCode PCFieldSplitSetRuntimeSplits_Private(PC pc)
352: {
353: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
354: PetscInt bs, i, nfields, *ifields, nfields_col, *ifields_col;
355: PetscBool flg, flg_col, mnest;
356: char optionname[128], splitname[8], optionname_col[128];
358: PetscFunctionBegin;
359: PetscCall(PetscObjectTypeCompare((PetscObject)pc->mat, MATNEST, &mnest));
360: if (mnest) PetscCall(MatNestGetSize(pc->pmat, &bs, NULL));
361: else bs = jac->bs;
362: PetscCall(PetscMalloc2(bs, &ifields, bs, &ifields_col));
363: for (i = 0, flg = PETSC_TRUE;; i++) {
364: PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i));
365: PetscCall(PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%" PetscInt_FMT "_fields", i));
366: PetscCall(PetscSNPrintf(optionname_col, sizeof(optionname_col), "-pc_fieldsplit_%" PetscInt_FMT "_fields_col", i));
367: nfields = bs;
368: nfields_col = bs;
369: PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname, ifields, &nfields, &flg));
370: PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname_col, ifields_col, &nfields_col, &flg_col));
371: if (!flg) break;
372: else if (flg && !flg_col) {
373: PetscCheck(nfields, PETSC_COMM_SELF, PETSC_ERR_USER, "Cannot list zero fields");
374: PetscCall(PCFieldSplitSetFields(pc, splitname, nfields, ifields, ifields));
375: } else {
376: PetscCheck(nfields && nfields_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Cannot list zero fields");
377: PetscCheck(nfields == nfields_col, PETSC_COMM_SELF, PETSC_ERR_USER, "Number of row and column fields must match");
378: PetscCall(PCFieldSplitSetFields(pc, splitname, nfields, ifields, ifields_col));
379: }
380: }
381: if (i > 0) {
382: /* Makes command-line setting of splits take precedence over setting them in code.
383: Otherwise subsequent calls to PCFieldSplitSetIS() or PCFieldSplitSetFields() would
384: create new splits, which would probably not be what the user wanted. */
385: jac->splitdefined = PETSC_TRUE;
386: }
387: PetscCall(PetscFree2(ifields, ifields_col));
388: PetscFunctionReturn(PETSC_SUCCESS);
389: }
391: static PetscErrorCode PCFieldSplitSetDefaults(PC pc)
392: {
393: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
394: PC_FieldSplitLink ilink = jac->head;
395: PetscBool fieldsplit_default = PETSC_FALSE, coupling = PETSC_FALSE;
396: PetscInt i;
398: PetscFunctionBegin;
399: /*
400: Kinda messy, but at least this now uses DMCreateFieldDecomposition().
401: Should probably be rewritten.
402: */
403: if (!ilink) {
404: PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_detect_coupling", &coupling, NULL));
405: if (pc->dm && jac->dm_splits && !jac->detect && !coupling) {
406: PetscInt numFields, f, i, j;
407: char **fieldNames;
408: IS *fields;
409: DM *dms;
410: DM subdm[128];
411: PetscBool flg;
413: PetscCall(DMCreateFieldDecomposition(pc->dm, &numFields, &fieldNames, &fields, &dms));
414: /* Allow the user to prescribe the splits */
415: for (i = 0, flg = PETSC_TRUE;; i++) {
416: PetscInt ifields[128];
417: IS compField;
418: char optionname[128], splitname[8];
419: PetscInt nfields = numFields;
421: PetscCall(PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%" PetscInt_FMT "_fields", i));
422: PetscCall(PetscOptionsGetIntArray(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, optionname, ifields, &nfields, &flg));
423: if (!flg) break;
424: PetscCheck(numFields <= 128, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Cannot currently support %" PetscInt_FMT " > 128 fields", numFields);
425: PetscCall(DMCreateSubDM(pc->dm, nfields, ifields, &compField, &subdm[i]));
426: if (nfields == 1) PetscCall(PCFieldSplitSetIS(pc, fieldNames[ifields[0]], compField));
427: else {
428: PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i));
429: PetscCall(PCFieldSplitSetIS(pc, splitname, compField));
430: }
431: PetscCall(ISDestroy(&compField));
432: for (j = 0; j < nfields; ++j) {
433: f = ifields[j];
434: PetscCall(PetscFree(fieldNames[f]));
435: PetscCall(ISDestroy(&fields[f]));
436: }
437: }
438: if (i == 0) {
439: for (f = 0; f < numFields; ++f) {
440: PetscCall(PCFieldSplitSetIS(pc, fieldNames[f], fields[f]));
441: PetscCall(PetscFree(fieldNames[f]));
442: PetscCall(ISDestroy(&fields[f]));
443: }
444: } else {
445: for (j = 0; j < numFields; j++) PetscCall(DMDestroy(dms + j));
446: PetscCall(PetscFree(dms));
447: PetscCall(PetscMalloc1(i, &dms));
448: for (j = 0; j < i; ++j) dms[j] = subdm[j];
449: }
450: PetscCall(PetscFree(fieldNames));
451: PetscCall(PetscFree(fields));
452: if (dms) {
453: PetscCall(PetscInfo(pc, "Setting up physics based fieldsplit preconditioner using the embedded DM\n"));
454: for (ilink = jac->head, i = 0; ilink; ilink = ilink->next, ++i) {
455: const char *prefix;
456: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)ilink->ksp, &prefix));
457: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)dms[i], prefix));
458: PetscCall(KSPSetDM(ilink->ksp, dms[i]));
459: PetscCall(KSPSetDMActive(ilink->ksp, KSP_DMACTIVE_ALL, PETSC_FALSE));
460: PetscCall(PetscObjectIncrementTabLevel((PetscObject)dms[i], (PetscObject)ilink->ksp, 0));
461: PetscCall(DMDestroy(&dms[i]));
462: }
463: PetscCall(PetscFree(dms));
464: }
465: } else {
466: if (jac->bs <= 0) {
467: if (pc->pmat) PetscCall(MatGetBlockSize(pc->pmat, &jac->bs));
468: else jac->bs = 1;
469: }
471: if (jac->detect) {
472: IS zerodiags, rest;
473: PetscInt nmin, nmax;
475: PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax));
476: if (jac->diag_use_amat) {
477: PetscCall(MatFindZeroDiagonals(pc->mat, &zerodiags));
478: } else {
479: PetscCall(MatFindZeroDiagonals(pc->pmat, &zerodiags));
480: }
481: PetscCall(ISComplement(zerodiags, nmin, nmax, &rest));
482: PetscCall(PCFieldSplitSetIS(pc, "0", rest));
483: PetscCall(PCFieldSplitSetIS(pc, "1", zerodiags));
484: PetscCall(ISDestroy(&zerodiags));
485: PetscCall(ISDestroy(&rest));
486: } else if (coupling) {
487: IS coupling, rest;
488: PetscInt nmin, nmax;
490: PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax));
491: if (jac->offdiag_use_amat) {
492: PetscCall(MatFindOffBlockDiagonalEntries(pc->mat, &coupling));
493: } else {
494: PetscCall(MatFindOffBlockDiagonalEntries(pc->pmat, &coupling));
495: }
496: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc->mat), nmax - nmin, nmin, 1, &rest));
497: PetscCall(ISSetIdentity(rest));
498: PetscCall(PCFieldSplitSetIS(pc, "0", rest));
499: PetscCall(PCFieldSplitSetIS(pc, "1", coupling));
500: PetscCall(ISDestroy(&coupling));
501: PetscCall(ISDestroy(&rest));
502: } else {
503: PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_default", &fieldsplit_default, NULL));
504: if (!fieldsplit_default) {
505: /* Allow user to set fields from command line, if bs was known at the time of PCSetFromOptions_FieldSplit()
506: then it is set there. This is not ideal because we should only have options set in XXSetFromOptions(). */
507: PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc));
508: if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n"));
509: }
510: if ((fieldsplit_default || !jac->splitdefined) && !jac->isrestrict) {
511: Mat M = pc->pmat;
512: PetscBool isnest;
513: PetscInt nf;
515: PetscCall(PetscInfo(pc, "Using default splitting of fields\n"));
516: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &isnest));
517: if (!isnest) {
518: M = pc->mat;
519: PetscCall(PetscObjectTypeCompare((PetscObject)pc->mat, MATNEST, &isnest));
520: }
521: if (!isnest) nf = jac->bs;
522: else PetscCall(MatNestGetSize(M, &nf, NULL));
523: for (i = 0; i < nf; i++) {
524: char splitname[8];
526: PetscCall(PetscSNPrintf(splitname, sizeof(splitname), "%" PetscInt_FMT, i));
527: PetscCall(PCFieldSplitSetFields(pc, splitname, 1, &i, &i));
528: }
529: jac->defaultsplit = PETSC_TRUE;
530: }
531: }
532: }
533: } else if (jac->nsplits == 1) {
534: IS is2;
535: PetscInt nmin, nmax;
537: PetscCheck(ilink->is, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Must provide at least two sets of fields to PCFieldSplit()");
538: PetscCall(MatGetOwnershipRange(pc->mat, &nmin, &nmax));
539: PetscCall(ISComplement(ilink->is, nmin, nmax, &is2));
540: PetscCall(PCFieldSplitSetIS(pc, "1", is2));
541: PetscCall(ISDestroy(&is2));
542: }
544: PetscCheck(jac->nsplits >= 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unhandled case, must have at least two fields, not %" PetscInt_FMT, jac->nsplits);
545: PetscFunctionReturn(PETSC_SUCCESS);
546: }
548: static PetscErrorCode MatGolubKahanComputeExplicitOperator(Mat A, Mat B, Mat C, Mat *H, PetscReal gkbnu)
549: {
550: Mat BT, T;
551: PetscReal nrmT, nrmB;
553: PetscFunctionBegin;
554: PetscCall(MatHermitianTranspose(C, MAT_INITIAL_MATRIX, &T)); /* Test if augmented matrix is symmetric */
555: PetscCall(MatAXPY(T, -1.0, B, DIFFERENT_NONZERO_PATTERN));
556: PetscCall(MatNorm(T, NORM_1, &nrmT));
557: PetscCall(MatNorm(B, NORM_1, &nrmB));
558: PetscCheck(nrmB <= 0 || nrmT / nrmB < PETSC_SMALL, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Matrix is not symmetric/Hermitian, GKB is not applicable.");
560: /* Compute augmented Lagrangian matrix H = A00 + nu*A01*A01'. This corresponds to */
561: /* setting N := 1/nu*I in [Ar13]. */
562: PetscCall(MatHermitianTranspose(B, MAT_INITIAL_MATRIX, &BT));
563: PetscCall(MatMatMult(B, BT, MAT_INITIAL_MATRIX, PETSC_CURRENT, H)); /* H = A01*A01' */
564: PetscCall(MatAYPX(*H, gkbnu, A, DIFFERENT_NONZERO_PATTERN)); /* H = A00 + nu*A01*A01' */
566: PetscCall(MatDestroy(&BT));
567: PetscCall(MatDestroy(&T));
568: PetscFunctionReturn(PETSC_SUCCESS);
569: }
571: PETSC_EXTERN PetscErrorCode PetscOptionsFindPairPrefix_Private(PetscOptions, const char pre[], const char name[], const char *option[], const char *value[], PetscBool *flg);
573: static PetscErrorCode PCSetUp_FieldSplit(PC pc)
574: {
575: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
576: PC_FieldSplitLink ilink;
577: PetscInt i, nsplit;
578: PetscBool matnest = PETSC_FALSE;
580: PetscFunctionBegin;
581: pc->failedreason = PC_NOERROR;
582: PetscCall(PCFieldSplitSetDefaults(pc));
583: nsplit = jac->nsplits;
584: ilink = jac->head;
585: if (pc->pmat) PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
587: /* get the matrices for each split */
588: if (!jac->issetup) {
589: PetscInt rstart, rend, nslots, bs;
591: jac->issetup = PETSC_TRUE;
593: /* This is done here instead of in PCFieldSplitSetFields() because may not have matrix at that point */
594: if (jac->defaultsplit || !ilink->is) {
595: if (jac->bs <= 0) jac->bs = nsplit;
596: }
598: /* MatCreateSubMatrix() for [S]BAIJ matrices can only work if the indices include entire blocks of the matrix */
599: PetscCall(MatGetBlockSize(pc->pmat, &bs));
600: if (bs > 1 && (jac->bs <= bs || jac->bs % bs)) {
601: PetscBool blk;
603: PetscCall(PetscObjectTypeCompareAny((PetscObject)pc->pmat, &blk, MATBAIJ, MATSBAIJ, MATSEQBAIJ, MATSEQSBAIJ, MATMPIBAIJ, MATMPISBAIJ, NULL));
604: PetscCheck(!blk, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Cannot use MATBAIJ with PCFIELDSPLIT and currently set matrix and PC blocksizes");
605: }
607: if (!matnest) { /* use the matrix blocksize and stride IS to determine the index sets that define the submatrices */
608: bs = jac->bs;
609: PetscCall(MatGetOwnershipRange(pc->pmat, &rstart, &rend));
610: nslots = (rend - rstart) / bs;
611: for (i = 0; i < nsplit; i++) {
612: if (jac->defaultsplit) {
613: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + i, nsplit, &ilink->is));
614: PetscCall(PetscObjectReference((PetscObject)ilink->is));
615: ilink->is_col = ilink->is;
616: } else if (!ilink->is) {
617: PetscBool same_fields = PETSC_TRUE;
619: for (PetscInt k = 0; k < ilink->nfields; k++) {
620: if (ilink->fields[k] != ilink->fields_col[k]) same_fields = PETSC_FALSE;
621: }
623: if (ilink->nfields > 1) {
624: PetscInt *ii, *jj, j, k, nfields = ilink->nfields, *fields = ilink->fields, *fields_col = ilink->fields_col;
626: PetscCall(PetscMalloc1(ilink->nfields * nslots, &ii));
627: if (!same_fields) PetscCall(PetscMalloc1(ilink->nfields * nslots, &jj));
628: for (j = 0; j < nslots; j++) {
629: for (k = 0; k < nfields; k++) {
630: ii[nfields * j + k] = rstart + bs * j + fields[k];
631: if (!same_fields) jj[nfields * j + k] = rstart + bs * j + fields_col[k];
632: }
633: }
634: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, ii, PETSC_OWN_POINTER, &ilink->is));
635: if (!same_fields) PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), nslots * nfields, jj, PETSC_OWN_POINTER, &ilink->is_col));
636: else {
637: PetscCall(PetscObjectReference((PetscObject)ilink->is));
638: ilink->is_col = ilink->is;
639: }
640: PetscCall(ISSetBlockSize(ilink->is, nfields));
641: PetscCall(ISSetBlockSize(ilink->is_col, nfields));
642: } else {
643: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields[0], bs, &ilink->is));
644: if (!same_fields) PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), nslots, rstart + ilink->fields_col[0], bs, &ilink->is_col));
645: else {
646: PetscCall(PetscObjectReference((PetscObject)ilink->is));
647: ilink->is_col = ilink->is;
648: }
649: }
650: }
651: ilink = ilink->next;
652: }
653: } else { /* use the IS that define the MATNEST to determine the index sets that define the submatrices */
654: IS *rowis, *colis, *ises = NULL;
655: PetscInt mis, nis;
657: PetscCall(MatNestGetSize(pc->pmat, &mis, &nis));
658: PetscCall(PetscMalloc2(mis, &rowis, nis, &colis));
659: PetscCall(MatNestGetISs(pc->pmat, rowis, colis));
660: if (!jac->defaultsplit) PetscCall(PetscMalloc1(mis, &ises));
662: for (i = 0; i < nsplit; i++) {
663: if (jac->defaultsplit) {
664: PetscCall(ISDuplicate(rowis[i], &ilink->is));
665: PetscCall(PetscObjectReference((PetscObject)ilink->is));
666: ilink->is_col = ilink->is;
667: } else if (!ilink->is) {
668: if (ilink->nfields > 1) {
669: for (PetscInt j = 0; j < ilink->nfields; j++) ises[j] = rowis[ilink->fields[j]];
670: PetscCall(ISConcatenate(PetscObjectComm((PetscObject)pc), ilink->nfields, ises, &ilink->is));
671: } else {
672: PetscCall(ISDuplicate(rowis[ilink->fields[0]], &ilink->is));
673: }
674: PetscCall(PetscObjectReference((PetscObject)ilink->is));
675: ilink->is_col = ilink->is;
676: }
677: ilink = ilink->next;
678: }
679: PetscCall(PetscFree2(rowis, colis));
680: PetscCall(PetscFree(ises));
681: }
682: }
684: ilink = jac->head;
685: if (!jac->pmat) {
686: Vec xtmp;
688: PetscCall(MatCreateVecs(pc->pmat, &xtmp, NULL));
689: PetscCall(PetscMalloc1(nsplit, &jac->pmat));
690: PetscCall(PetscMalloc2(nsplit, &jac->x, nsplit, &jac->y));
691: for (i = 0; i < nsplit; i++) {
692: MatNullSpace sp;
694: /* Check for matrix attached to IS */
695: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&jac->pmat[i]));
696: if (jac->pmat[i]) {
697: PetscCall(PetscObjectReference((PetscObject)jac->pmat[i]));
698: if (jac->type == PC_COMPOSITE_SCHUR) {
699: jac->schur_user = jac->pmat[i];
701: PetscCall(PetscObjectReference((PetscObject)jac->schur_user));
702: }
703: } else {
704: const char *prefix;
705: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->pmat[i]));
706: PetscCall(MatGetOptionsPrefix(jac->pmat[i], &prefix));
707: if (!prefix) {
708: PetscCall(KSPGetOptionsPrefix(ilink->ksp, &prefix));
709: PetscCall(MatSetOptionsPrefix(jac->pmat[i], prefix));
710: }
711: PetscCall(MatSetFromOptions(jac->pmat[i]));
712: PetscCall(MatViewFromOptions(jac->pmat[i], NULL, "-mat_view"));
713: }
714: /* create work vectors for each split */
715: PetscCall(MatCreateVecs(jac->pmat[i], &jac->x[i], &jac->y[i]));
716: ilink->x = jac->x[i];
717: ilink->y = jac->y[i];
718: ilink->z = NULL;
719: /* compute scatter contexts needed by multiplicative versions and non-default splits */
720: PetscCall(VecScatterCreate(xtmp, ilink->is, jac->x[i], NULL, &ilink->sctx));
721: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nearnullspace", (PetscObject *)&sp));
722: if (sp) PetscCall(MatSetNearNullSpace(jac->pmat[i], sp));
723: ilink = ilink->next;
724: }
725: PetscCall(VecDestroy(&xtmp));
726: } else {
727: MatReuse scall;
728: MatNullSpace *nullsp = NULL;
730: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
731: PetscCall(MatGetNullSpaces(nsplit, jac->pmat, &nullsp));
732: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->pmat[i]));
733: scall = MAT_INITIAL_MATRIX;
734: } else scall = MAT_REUSE_MATRIX;
736: for (i = 0; i < nsplit; i++) {
737: Mat pmat;
739: /* Check for matrix attached to IS */
740: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "pmat", (PetscObject *)&pmat));
741: if (!pmat) PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, ilink->is_col, scall, &jac->pmat[i]));
742: ilink = ilink->next;
743: }
744: if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->pmat, &nullsp));
745: }
746: if (jac->diag_use_amat) {
747: ilink = jac->head;
748: if (!jac->mat) {
749: PetscCall(PetscMalloc1(nsplit, &jac->mat));
750: for (i = 0; i < nsplit; i++) {
751: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, MAT_INITIAL_MATRIX, &jac->mat[i]));
752: ilink = ilink->next;
753: }
754: } else {
755: MatReuse scall;
756: MatNullSpace *nullsp = NULL;
758: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
759: PetscCall(MatGetNullSpaces(nsplit, jac->mat, &nullsp));
760: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->mat[i]));
761: scall = MAT_INITIAL_MATRIX;
762: } else scall = MAT_REUSE_MATRIX;
764: for (i = 0; i < nsplit; i++) {
765: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, ilink->is_col, scall, &jac->mat[i]));
766: ilink = ilink->next;
767: }
768: if (nullsp) PetscCall(MatRestoreNullSpaces(nsplit, jac->mat, &nullsp));
769: }
770: } else {
771: jac->mat = jac->pmat;
772: }
774: /* Check for null space attached to IS */
775: ilink = jac->head;
776: for (i = 0; i < nsplit; i++) {
777: MatNullSpace sp;
779: PetscCall(PetscObjectQuery((PetscObject)ilink->is, "nullspace", (PetscObject *)&sp));
780: if (sp) PetscCall(MatSetNullSpace(jac->mat[i], sp));
781: ilink = ilink->next;
782: }
784: if (jac->type != PC_COMPOSITE_ADDITIVE && jac->type != PC_COMPOSITE_SCHUR && jac->type != PC_COMPOSITE_GKB) {
785: /* extract the rows of the matrix associated with each field: used for efficient computation of residual inside algorithm */
786: /* FIXME: Can/should we reuse jac->mat whenever (jac->diag_use_amat) is true? */
787: ilink = jac->head;
788: if (nsplit == 2 && jac->type == PC_COMPOSITE_MULTIPLICATIVE) {
789: /* 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 */
790: if (!jac->Afield) {
791: PetscCall(PetscCalloc1(nsplit, &jac->Afield));
792: if (jac->offdiag_use_amat) {
793: PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1]));
794: } else {
795: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->Afield[1]));
796: }
797: } else {
798: MatReuse scall;
800: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
801: PetscCall(MatDestroy(&jac->Afield[1]));
802: scall = MAT_INITIAL_MATRIX;
803: } else scall = MAT_REUSE_MATRIX;
805: if (jac->offdiag_use_amat) {
806: PetscCall(MatCreateSubMatrix(pc->mat, ilink->next->is, ilink->is, scall, &jac->Afield[1]));
807: } else {
808: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->next->is, ilink->is, scall, &jac->Afield[1]));
809: }
810: }
811: } else {
812: if (!jac->Afield) {
813: PetscCall(PetscMalloc1(nsplit, &jac->Afield));
814: for (i = 0; i < nsplit; i++) {
815: if (jac->offdiag_use_amat) {
816: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i]));
817: } else {
818: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, MAT_INITIAL_MATRIX, &jac->Afield[i]));
819: }
820: ilink = ilink->next;
821: }
822: } else {
823: MatReuse scall;
824: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
825: for (i = 0; i < nsplit; i++) PetscCall(MatDestroy(&jac->Afield[i]));
826: scall = MAT_INITIAL_MATRIX;
827: } else scall = MAT_REUSE_MATRIX;
829: for (i = 0; i < nsplit; i++) {
830: if (jac->offdiag_use_amat) {
831: PetscCall(MatCreateSubMatrix(pc->mat, ilink->is, NULL, scall, &jac->Afield[i]));
832: } else {
833: PetscCall(MatCreateSubMatrix(pc->pmat, ilink->is, NULL, scall, &jac->Afield[i]));
834: }
835: ilink = ilink->next;
836: }
837: }
838: }
839: }
841: if (jac->type == PC_COMPOSITE_SCHUR) {
842: PetscBool isset, isspd = PETSC_FALSE, issym = PETSC_FALSE, flg;
843: char lscname[256];
844: PetscObject LSC_L;
846: PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use Schur complement preconditioner you must have exactly 2 fields");
848: /* If pc->mat is SPD, don't scale by -1 the Schur complement */
849: PetscCall(MatIsSPDKnown(pc->pmat, &isset, &isspd));
850: if (jac->schurscale == (PetscScalar)-1.0) jac->schurscale = (isset && isspd) ? 1.0 : -1.0;
851: PetscCall(MatIsSymmetricKnown(pc->pmat, &isset, &issym));
853: PetscCall(PetscObjectTypeCompareAny(jac->offdiag_use_amat ? (PetscObject)pc->mat : (PetscObject)pc->pmat, &flg, MATSEQSBAIJ, MATMPISBAIJ, ""));
855: if (jac->schur) {
856: KSP kspA = jac->head->ksp, kspInner = NULL, kspUpper = jac->kspupper;
857: MatReuse scall;
859: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
860: scall = MAT_INITIAL_MATRIX;
861: PetscCall(MatDestroy(&jac->B));
862: PetscCall(MatDestroy(&jac->C));
863: } else scall = MAT_REUSE_MATRIX;
865: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
866: ilink = jac->head;
867: PetscCall(MatCreateSubMatrix(jac->offdiag_use_amat ? pc->mat : pc->pmat, ilink->is, ilink->next->is, scall, &jac->B));
868: if (!flg) PetscCall(MatCreateSubMatrix(jac->offdiag_use_amat ? pc->mat : pc->pmat, ilink->next->is, ilink->is, scall, &jac->C));
869: else {
870: PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &isset, &flg));
871: if (isset && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C));
872: else PetscCall(MatCreateTranspose(jac->B, &jac->C));
873: }
874: ilink = ilink->next;
875: PetscCall(MatSchurComplementUpdateSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1]));
876: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) {
877: PetscCall(MatDestroy(&jac->schurp));
878: PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp));
879: } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL && jac->kspupper != jac->head->ksp) {
880: PetscCall(MatDestroy(&jac->schur_user));
881: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
882: }
883: if (kspA != kspInner) PetscCall(KSPSetOperators(kspA, jac->mat[0], jac->pmat[0]));
884: if (kspUpper != kspA) PetscCall(KSPSetOperators(kspUpper, jac->mat[0], jac->pmat[0]));
885: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac)));
886: } else {
887: const char *Dprefix;
888: char schurprefix[256], schurmatprefix[256];
889: char schurtestoption[256];
890: MatNullSpace sp;
891: KSP kspt;
893: /* extract the A01 and A10 matrices */
894: ilink = jac->head;
895: PetscCall(MatCreateSubMatrix(jac->offdiag_use_amat ? pc->mat : pc->pmat, ilink->is, ilink->next->is, MAT_INITIAL_MATRIX, &jac->B));
896: if (!flg) PetscCall(MatCreateSubMatrix(jac->offdiag_use_amat ? pc->mat : pc->pmat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->C));
897: else {
898: PetscCall(MatIsHermitianKnown(jac->offdiag_use_amat ? pc->mat : pc->pmat, &isset, &flg));
899: if (isset && flg) PetscCall(MatCreateHermitianTranspose(jac->B, &jac->C));
900: else PetscCall(MatCreateTranspose(jac->B, &jac->C));
901: }
902: ilink = ilink->next;
903: /* Use mat[0] (diagonal block of Amat) preconditioned by pmat[0] to define Schur complement */
904: PetscCall(MatCreate(((PetscObject)jac->mat[0])->comm, &jac->schur));
905: PetscCall(MatSetType(jac->schur, MATSCHURCOMPLEMENT));
906: PetscCall(MatSchurComplementSetSubMatrices(jac->schur, jac->mat[0], jac->pmat[0], jac->B, jac->C, jac->mat[1]));
907: PetscCall(PetscSNPrintf(schurmatprefix, sizeof(schurmatprefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
908: PetscCall(MatSetOptionsPrefix(jac->schur, schurmatprefix));
909: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspt));
910: PetscCall(KSPSetOptionsPrefix(kspt, schurmatprefix));
912: /* Note: this is not true in general */
913: PetscCall(MatGetNullSpace(jac->mat[1], &sp));
914: if (sp) PetscCall(MatSetNullSpace(jac->schur, sp));
916: PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_inner_", ilink->splitname));
917: PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg));
918: if (flg) {
919: DM dmInner;
920: KSP kspInner;
921: PC pcInner;
923: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
924: PetscCall(KSPReset(kspInner));
925: PetscCall(KSPSetOperators(kspInner, jac->mat[0], jac->pmat[0]));
926: PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_inner_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
927: /* Indent this deeper to emphasize the "inner" nature of this solver. */
928: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner, (PetscObject)pc, 2));
929: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspInner->pc, (PetscObject)pc, 2));
930: PetscCall(KSPSetOptionsPrefix(kspInner, schurprefix));
932: /* Set DM for new solver */
933: PetscCall(KSPGetDM(jac->head->ksp, &dmInner));
934: PetscCall(KSPSetDM(kspInner, dmInner));
935: PetscCall(KSPSetDMActive(kspInner, KSP_DMACTIVE_ALL, PETSC_FALSE));
937: /* Defaults to PCKSP as preconditioner */
938: PetscCall(KSPGetPC(kspInner, &pcInner));
939: PetscCall(PCSetType(pcInner, PCKSP));
940: PetscCall(PCKSPSetKSP(pcInner, jac->head->ksp));
941: } else {
942: /* Use the outer solver for the inner solve, but revert the KSPPREONLY from PCFieldSplitSetFields_FieldSplit or
943: * PCFieldSplitSetIS_FieldSplit. We don't want KSPPREONLY because it makes the Schur complement inexact,
944: * preventing Schur complement reduction to be an accurate solve. Usually when an iterative solver is used for
945: * S = D - C A_inner^{-1} B, we expect S to be defined using an accurate definition of A_inner^{-1}, so we make
946: * GMRES the default. Note that it is also common to use PREONLY for S, in which case S may not be used
947: * directly, and the user is responsible for setting an inexact method for fieldsplit's A^{-1}. */
948: PetscCall(KSPSetType(jac->head->ksp, KSPGMRES));
949: PetscCall(MatSchurComplementSetKSP(jac->schur, jac->head->ksp));
950: }
951: PetscCall(KSPSetOperators(jac->head->ksp, jac->mat[0], jac->pmat[0]));
952: PetscCall(KSPSetFromOptions(jac->head->ksp));
953: PetscCall(MatSetFromOptions(jac->schur));
955: PetscCall(PetscObjectTypeCompare((PetscObject)jac->schur, MATSCHURCOMPLEMENT, &flg));
956: if (flg) { /* Need to do this otherwise PCSetUp_KSP will overwrite the amat of jac->head->ksp */
957: KSP kspInner;
958: PC pcInner;
960: PetscCall(MatSchurComplementGetKSP(jac->schur, &kspInner));
961: PetscCall(KSPGetPC(kspInner, &pcInner));
962: PetscCall(PetscObjectTypeCompare((PetscObject)pcInner, PCKSP, &flg));
963: if (flg) {
964: KSP ksp;
966: PetscCall(PCKSPGetKSP(pcInner, &ksp));
967: if (ksp == jac->head->ksp) PetscCall(PCSetUseAmat(pcInner, PETSC_TRUE));
968: }
969: }
970: PetscCall(PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_upper_", ilink->splitname));
971: PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, schurtestoption, NULL, NULL, &flg));
972: if (flg) {
973: DM dmInner;
975: PetscCall(PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_upper_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
976: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspupper));
977: PetscCall(KSPSetNestLevel(jac->kspupper, pc->kspnestlevel));
978: PetscCall(KSPSetErrorIfNotConverged(jac->kspupper, pc->erroriffailure));
979: PetscCall(KSPSetOptionsPrefix(jac->kspupper, schurprefix));
980: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper, (PetscObject)pc, 1));
981: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspupper->pc, (PetscObject)pc, 1));
982: PetscCall(KSPGetDM(jac->head->ksp, &dmInner));
983: PetscCall(KSPSetDM(jac->kspupper, dmInner));
984: PetscCall(KSPSetDMActive(jac->kspupper, KSP_DMACTIVE_ALL, PETSC_FALSE));
985: PetscCall(KSPSetFromOptions(jac->kspupper));
986: PetscCall(KSPSetOperators(jac->kspupper, jac->mat[0], jac->pmat[0]));
987: PetscCall(VecDuplicate(jac->head->x, &jac->head->z));
988: } else {
989: jac->kspupper = jac->head->ksp;
990: PetscCall(PetscObjectReference((PetscObject)jac->head->ksp));
991: }
993: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) PetscCall(MatSchurComplementGetPmat(jac->schur, MAT_INITIAL_MATRIX, &jac->schurp));
994: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspschur));
995: PetscCall(KSPSetNestLevel(jac->kspschur, pc->kspnestlevel));
996: PetscCall(KSPSetErrorIfNotConverged(jac->kspschur, pc->erroriffailure));
997: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspschur, (PetscObject)pc, 1));
998: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) {
999: PC pcschur;
1000: PetscCall(KSPGetPC(jac->kspschur, &pcschur));
1001: PetscCall(PCSetType(pcschur, PCNONE));
1002: /* Note: This is bad if there exist preconditioners for MATSCHURCOMPLEMENT */
1003: } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL) {
1004: if (jac->schurfactorization != PC_FIELDSPLIT_SCHUR_FACT_FULL || jac->kspupper != jac->head->ksp) PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1005: }
1006: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, FieldSplitSchurPre(jac)));
1007: PetscCall(KSPGetOptionsPrefix(jac->head->next->ksp, &Dprefix));
1008: PetscCall(KSPSetOptionsPrefix(jac->kspschur, Dprefix));
1009: /* propagate DM */
1010: {
1011: DM sdm;
1012: PetscCall(KSPGetDM(jac->head->next->ksp, &sdm));
1013: if (sdm) {
1014: PetscCall(KSPSetDM(jac->kspschur, sdm));
1015: PetscCall(KSPSetDMActive(jac->kspschur, KSP_DMACTIVE_ALL, PETSC_FALSE));
1016: }
1017: }
1018: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
1019: /* need to call this every time, since the jac->kspschur is freshly created, otherwise its options never get set */
1020: PetscCall(KSPSetFromOptions(jac->kspschur));
1021: }
1022: PetscCall(MatAssemblyBegin(jac->schur, MAT_FINAL_ASSEMBLY));
1023: PetscCall(MatAssemblyEnd(jac->schur, MAT_FINAL_ASSEMBLY));
1024: if (issym) PetscCall(MatSetOption(jac->schur, MAT_SYMMETRIC, PETSC_TRUE));
1025: if (isspd) PetscCall(MatSetOption(jac->schur, MAT_SPD, PETSC_TRUE));
1027: /* HACK: special support to forward L and Lp matrices that might be used by PCLSC */
1028: PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_L", ilink->splitname));
1029: PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, &LSC_L));
1030: if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, &LSC_L));
1031: if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_L", LSC_L));
1032: PetscCall(PetscSNPrintf(lscname, sizeof(lscname), "%s_LSC_Lp", ilink->splitname));
1033: PetscCall(PetscObjectQuery((PetscObject)pc->pmat, lscname, &LSC_L));
1034: if (!LSC_L) PetscCall(PetscObjectQuery((PetscObject)pc->mat, lscname, &LSC_L));
1035: if (LSC_L) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "LSC_Lp", LSC_L));
1036: } else if (jac->type == PC_COMPOSITE_GKB) {
1037: PetscCheck(nsplit == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "To use GKB preconditioner you must have exactly 2 fields");
1038: ilink = jac->head;
1039: PetscCall(MatCreateSubMatrix(jac->offdiag_use_amat ? pc->mat : pc->pmat, ilink->is, ilink->next->is, MAT_INITIAL_MATRIX, &jac->B));
1040: /* Create work vectors for GKB algorithm */
1041: PetscCall(VecDuplicate(ilink->x, &jac->u));
1042: PetscCall(VecDuplicate(ilink->x, &jac->Hu));
1043: PetscCall(VecDuplicate(ilink->x, &jac->w2));
1044: PetscCall(MatCreateSubMatrix(jac->offdiag_use_amat ? pc->mat : pc->pmat, ilink->next->is, ilink->is, MAT_INITIAL_MATRIX, &jac->C));
1045: ilink = ilink->next;
1046: /* Create work vectors for GKB algorithm */
1047: PetscCall(VecDuplicate(ilink->x, &jac->v));
1048: PetscCall(VecDuplicate(ilink->x, &jac->d));
1049: PetscCall(VecDuplicate(ilink->x, &jac->w1));
1050: PetscCall(MatGolubKahanComputeExplicitOperator(jac->mat[0], jac->B, jac->C, &jac->H, jac->gkbnu));
1051: PetscCall(PetscCalloc1(jac->gkbdelay, &jac->vecz));
1053: ilink = jac->head;
1054: PetscCall(KSPSetOperators(ilink->ksp, jac->H, jac->H));
1055: if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp));
1056: /* Create gkb_monitor context */
1057: if (jac->gkbmonitor) {
1058: PetscInt tablevel;
1059: PetscCall(PetscViewerCreate(PETSC_COMM_WORLD, &jac->gkbviewer));
1060: PetscCall(PetscViewerSetType(jac->gkbviewer, PETSCVIEWERASCII));
1061: PetscCall(PetscObjectGetTabLevel((PetscObject)ilink->ksp, &tablevel));
1062: PetscCall(PetscViewerASCIISetTab(jac->gkbviewer, tablevel));
1063: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)ilink->ksp, 1));
1064: }
1065: } else {
1066: /* set up the individual splits' PCs */
1067: i = 0;
1068: ilink = jac->head;
1069: while (ilink) {
1070: PetscCall(KSPSetOperators(ilink->ksp, jac->mat[i], jac->pmat[i]));
1071: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
1072: if (!jac->suboptionsset) PetscCall(KSPSetFromOptions(ilink->ksp));
1073: i++;
1074: ilink = ilink->next;
1075: }
1076: }
1078: /* Set coordinates to the sub PC objects whenever these are set */
1079: if (jac->coordinates_set) {
1080: PC pc_coords;
1081: if (jac->type == PC_COMPOSITE_SCHUR) {
1082: // Head is first block.
1083: PetscCall(KSPGetPC(jac->head->ksp, &pc_coords));
1084: PetscCall(PCSetCoordinates(pc_coords, jac->head->dim, jac->head->ndofs, jac->head->coords));
1085: // Second one is Schur block, but its KSP object is in kspschur.
1086: PetscCall(KSPGetPC(jac->kspschur, &pc_coords));
1087: PetscCall(PCSetCoordinates(pc_coords, jac->head->next->dim, jac->head->next->ndofs, jac->head->next->coords));
1088: } else if (jac->type == PC_COMPOSITE_GKB) {
1089: PetscCall(PetscInfo(pc, "Warning: Setting coordinates does nothing for the GKB Fieldpslit preconditioner\n"));
1090: } else {
1091: ilink = jac->head;
1092: while (ilink) {
1093: PetscCall(KSPGetPC(ilink->ksp, &pc_coords));
1094: PetscCall(PCSetCoordinates(pc_coords, ilink->dim, ilink->ndofs, ilink->coords));
1095: ilink = ilink->next;
1096: }
1097: }
1098: }
1100: jac->suboptionsset = PETSC_TRUE;
1101: PetscFunctionReturn(PETSC_SUCCESS);
1102: }
1104: static PetscErrorCode PCSetUpOnBlocks_FieldSplit_Schur(PC pc)
1105: {
1106: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1107: PC_FieldSplitLink ilinkA = jac->head;
1108: KSP kspA = ilinkA->ksp, kspUpper = jac->kspupper;
1110: PetscFunctionBegin;
1111: if (jac->schurfactorization == PC_FIELDSPLIT_SCHUR_FACT_FULL && kspUpper != kspA) {
1112: PetscCall(KSPSetUp(kspUpper));
1113: PetscCall(KSPSetUpOnBlocks(kspUpper));
1114: }
1115: PetscCall(KSPSetUp(kspA));
1116: PetscCall(KSPSetUpOnBlocks(kspA));
1117: if (jac->schurpre != PC_FIELDSPLIT_SCHUR_PRE_FULL) {
1118: PetscCall(KSPSetUp(jac->kspschur));
1119: PetscCall(KSPSetUpOnBlocks(jac->kspschur));
1120: } else if (kspUpper == kspA && jac->schurfactorization == PC_FIELDSPLIT_SCHUR_FACT_FULL) {
1121: Mat A;
1122: PetscInt m, M, N;
1123: VecType vtype;
1124: PetscMemType mtype;
1125: PetscScalar *array;
1127: PetscCall(MatGetSize(jac->B, &M, &N));
1128: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1129: PetscCall(MatGetVecType(jac->B, &vtype));
1130: PetscCall(VecGetArrayAndMemType(ilinkA->x, &array, &mtype));
1131: PetscCall(VecRestoreArrayAndMemType(ilinkA->x, &array));
1132: PetscCall(PetscObjectQuery((PetscObject)jac->schur, "AinvB", (PetscObject *)&A));
1133: if (A) {
1134: PetscInt P;
1136: PetscCall(MatGetSize(A, NULL, &P));
1137: if (P < N + 1) { // need to recreate AinvB, otherwise, the Schur complement won't be updated
1138: PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", NULL));
1139: A = NULL;
1140: }
1141: }
1142: if (!A) {
1143: if (PetscMemTypeHost(mtype) || (!PetscDefined(HAVE_CUDA) && !PetscDefined(HAVE_HIP))) PetscCall(PetscMalloc1(m * (N + 1), &array));
1144: #if PetscDefined(HAVE_CUDA)
1145: else if (PetscMemTypeCUDA(mtype)) PetscCallCUDA(cudaMalloc((void **)&array, sizeof(PetscScalar) * m * (N + 1)));
1146: #endif
1147: #if PetscDefined(HAVE_HIP)
1148: else if (PetscMemTypeHIP(mtype)) PetscCallHIP(hipMalloc((void **)&array, sizeof(PetscScalar) * m * (N + 1)));
1149: #endif
1150: PetscCall(MatCreateDenseFromVecType(PetscObjectComm((PetscObject)jac->schur), vtype, m, PETSC_DECIDE, M, N + 1, PETSC_DECIDE, array, &A)); // number of columns of the Schur complement plus one
1151: PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", (PetscObject)A));
1152: PetscCall(MatDestroy(&A));
1153: }
1154: }
1155: PetscFunctionReturn(PETSC_SUCCESS);
1156: }
1158: static PetscErrorCode PCSetUpOnBlocks_FieldSplit(PC pc)
1159: {
1160: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1161: PC_FieldSplitLink ilink = jac->head;
1163: PetscFunctionBegin;
1164: while (ilink) {
1165: PetscCall(KSPSetUp(ilink->ksp));
1166: PetscCall(KSPSetUpOnBlocks(ilink->ksp));
1167: ilink = ilink->next;
1168: }
1169: PetscFunctionReturn(PETSC_SUCCESS);
1170: }
1172: static PetscErrorCode PCSetUpOnBlocks_FieldSplit_GKB(PC pc)
1173: {
1174: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1175: PC_FieldSplitLink ilinkA = jac->head;
1176: KSP ksp = ilinkA->ksp;
1178: PetscFunctionBegin;
1179: PetscCall(KSPSetUp(ksp));
1180: PetscCall(KSPSetUpOnBlocks(ksp));
1181: PetscFunctionReturn(PETSC_SUCCESS);
1182: }
1184: static PetscErrorCode PCApply_FieldSplit_Schur(PC pc, Vec x, Vec y)
1185: {
1186: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1187: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1188: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1189: Mat AinvB = NULL;
1190: PetscInt N, P;
1192: PetscFunctionBegin;
1193: switch (jac->schurfactorization) {
1194: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1195: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1196: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1197: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1198: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1199: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1200: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1201: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1202: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1203: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1204: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1205: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1206: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1207: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1208: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1209: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1210: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1211: PetscCall(VecScale(ilinkD->y, jac->schurscale));
1212: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1213: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1214: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1215: break;
1216: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1217: /* [A00 0; A10 S], suitable for left preconditioning */
1218: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1219: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1220: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1221: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1222: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1223: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1224: PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x));
1225: PetscCall(VecScale(ilinkD->x, -1.));
1226: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1227: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1228: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1229: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1230: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1231: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1232: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1233: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1234: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1235: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1236: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1237: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1238: break;
1239: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1240: /* [A00 A01; 0 S], suitable for right preconditioning */
1241: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1242: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1243: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1244: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1245: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1246: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1247: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1248: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1249: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->x));
1250: PetscCall(VecScale(ilinkA->x, -1.));
1251: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1252: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1253: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1254: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1255: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1256: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1257: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1258: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1259: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1260: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1261: break;
1262: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1263: /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1] */
1264: PetscCall(MatGetSize(jac->B, NULL, &P));
1265: N = P;
1266: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1267: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1268: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL));
1269: if (kspUpper == kspA) {
1270: PetscCall(PetscObjectQuery((PetscObject)jac->schur, "AinvB", (PetscObject *)&AinvB));
1271: if (AinvB) {
1272: PetscCall(MatGetSize(AinvB, NULL, &N));
1273: if (N > P) { // first time PCApply_FieldSplit_Schur() is called
1274: PetscMemType mtype;
1275: Vec c = NULL;
1276: PetscScalar *array;
1277: PetscInt m, M;
1279: PetscCall(MatGetSize(jac->B, &M, NULL));
1280: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1281: PetscCall(MatDenseGetArrayAndMemType(AinvB, &array, &mtype));
1282: if (PetscMemTypeHost(mtype) || (!PetscDefined(HAVE_CUDA) && !PetscDefined(HAVE_HIP))) PetscCall(VecCreateMPIWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1283: #if PetscDefined(HAVE_CUDA)
1284: else if (PetscMemTypeCUDA(mtype)) PetscCall(VecCreateMPICUDAWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1285: #endif
1286: #if PetscDefined(HAVE_HIP)
1287: else if (PetscMemTypeHIP(mtype)) PetscCall(VecCreateMPIHIPWithArray(PetscObjectComm((PetscObject)jac->schur), 1, m, M, array + m * P, &c));
1288: #endif
1289: PetscCall(MatDenseRestoreArrayAndMemType(AinvB, &array));
1290: PetscCall(VecCopy(ilinkA->x, c));
1291: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1292: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, jac->schur_user));
1293: PetscCall(VecCopy(c, ilinkA->y)); // retrieve the solution as the last column of the composed Mat
1294: PetscCall(VecDestroy(&c));
1295: }
1296: }
1297: }
1298: if (N == P) PetscCall(KSPSolve(kspLower, ilinkA->x, ilinkA->y));
1299: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->y));
1300: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL));
1301: PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x));
1302: PetscCall(VecScale(ilinkD->x, -1.0));
1303: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1304: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1306: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1307: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1308: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1309: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1310: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1311: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1312: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1314: if (kspUpper == kspA) {
1315: if (!AinvB) {
1316: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->y));
1317: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1318: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1319: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1320: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1321: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1322: } else PetscCall(MatMultAdd(AinvB, ilinkD->y, ilinkA->y, ilinkA->y));
1323: } else {
1324: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1325: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1326: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1327: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->x));
1328: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1329: PetscCall(KSPSolve(kspUpper, ilinkA->x, ilinkA->z));
1330: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->z));
1331: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1332: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1333: }
1334: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1335: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1336: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1337: }
1338: PetscFunctionReturn(PETSC_SUCCESS);
1339: }
1341: /*
1342: PCFieldSplitCreateWorkMats_Private - Allocate per-field dense work matrices for multi-RHS
1344: Input Parameters:
1345: + pc - the PC context
1346: - X - matrix to copy column-layout from
1348: Notes:
1349: If matrices already exist with correct column count, they are reused.
1350: If column count changed, old matrices are destroyed and new ones created.
1351: */
1352: static PetscErrorCode PCFieldSplitCreateWorkMats_Private(PC pc, Mat X)
1353: {
1354: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1355: PC_FieldSplitLink ilink = jac->head;
1356: PetscInt mx, Mx, my, My, N;
1358: PetscFunctionBegin;
1359: while (ilink) {
1360: /* check if reallocation needed (previous allocation with wrong column count) */
1361: if (ilink->X) {
1362: PetscCall(MatGetSize(ilink->X, NULL, &N));
1363: if (N != X->cmap->N) {
1364: PetscCall(MatDestroy(&ilink->X));
1365: PetscCall(MatDestroy(&ilink->Y));
1366: PetscCall(MatDestroy(&ilink->Z));
1367: }
1368: }
1369: /* create if needed */
1370: if (!ilink->X) {
1371: VecType xtype, ytype;
1373: PetscCall(VecGetType(ilink->x, &xtype));
1374: PetscCall(VecGetType(ilink->y, &ytype));
1375: PetscCall(VecGetLocalSize(ilink->x, &mx));
1376: PetscCall(VecGetSize(ilink->x, &Mx));
1377: PetscCall(VecGetLocalSize(ilink->y, &my));
1378: PetscCall(VecGetSize(ilink->y, &My));
1379: /* use default lda */
1380: PetscCall(MatCreateDenseFromVecType(PetscObjectComm((PetscObject)pc), xtype, mx, X->cmap->n, Mx, X->cmap->N, PETSC_DECIDE, NULL, &ilink->X));
1381: PetscCall(MatCreateDenseFromVecType(PetscObjectComm((PetscObject)pc), ytype, my, X->cmap->n, My, X->cmap->N, PETSC_DECIDE, NULL, &ilink->Y));
1382: }
1383: ilink = ilink->next;
1384: }
1385: PetscFunctionReturn(PETSC_SUCCESS);
1386: }
1388: static PetscErrorCode PCMatApply_FieldSplit_Schur(PC pc, Mat X, Mat Y)
1389: {
1390: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1391: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1392: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1393: Mat AinvB = NULL;
1394: PetscInt N, P;
1396: PetscFunctionBegin;
1397: /* create working matrices with the correct number of columns */
1398: PetscCall(PCFieldSplitCreateWorkMats_Private(pc, X));
1399: switch (jac->schurfactorization) {
1400: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1401: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1402: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, INSERT_VALUES, SCATTER_FORWARD));
1403: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, INSERT_VALUES, SCATTER_FORWARD));
1404: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1405: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1406: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1407: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1408: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1409: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1410: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1411: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1412: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1413: PetscCall(MatScale(ilinkD->Y, jac->schurscale));
1414: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1415: break;
1416: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1417: /* [A00 0; A10 S], suitable for left preconditioning */
1418: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, INSERT_VALUES, SCATTER_FORWARD));
1419: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1420: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1421: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1422: PetscCall(MatMatMult(jac->C, ilinkA->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkD->X));
1423: PetscCall(MatScale(ilinkD->X, -1.0));
1424: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, ADD_VALUES, SCATTER_FORWARD));
1425: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1426: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1427: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1428: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1429: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1430: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1431: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1432: break;
1433: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1434: /* [A00 A01; 0 S], suitable for right preconditioning */
1435: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, INSERT_VALUES, SCATTER_FORWARD));
1436: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1437: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1438: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1439: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1440: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1441: PetscCall(MatMatMult(jac->B, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->X));
1442: PetscCall(MatScale(ilinkA->X, -1.0));
1443: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, ADD_VALUES, SCATTER_FORWARD));
1444: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1445: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1446: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1447: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1448: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1449: break;
1450: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1451: /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1] */
1452: PetscCall(MatGetSize(jac->B, NULL, &P));
1453: N = P;
1454: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, INSERT_VALUES, SCATTER_FORWARD));
1455: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->X, ilinkA->Y, NULL));
1456: if (kspUpper == kspA) {
1457: PetscCall(PetscObjectQuery((PetscObject)jac->schur, "AinvB", (PetscObject *)&AinvB));
1458: if (AinvB) {
1459: PetscCall(MatGetSize(AinvB, NULL, &N));
1460: if (N > P) { // first time PCApply_FieldSplit_Schur() is called
1461: PetscMemType mtype;
1462: Mat C = NULL;
1463: PetscScalar *array;
1464: PetscInt m, M, q, Q, p;
1466: PetscCall(MatGetSize(jac->B, &M, NULL));
1467: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1468: PetscCall(MatGetSize(X, NULL, &Q));
1469: PetscCall(MatGetLocalSize(X, NULL, &q));
1470: PetscCall(MatDenseGetArrayAndMemType(AinvB, &array, &mtype));
1471: if (N != P + Q) {
1472: Mat replace;
1474: PetscCall(MatGetLocalSize(jac->B, NULL, &p));
1475: if (PetscMemTypeCUDA(mtype)) {
1476: #if PetscDefined(HAVE_CUDA)
1477: PetscCallCUDA(cudaFree(array));
1478: PetscCallCUDA(cudaMalloc((void **)&array, sizeof(PetscScalar) * m * (P + Q)));
1479: #endif
1480: } else if (PetscMemTypeHIP(mtype)) {
1481: #if PetscDefined(HAVE_HIP)
1482: PetscCallHIP(hipFree(array));
1483: PetscCallHIP(hipMalloc((void **)&array, sizeof(PetscScalar) * m * (P + Q)));
1484: #endif
1485: } else {
1486: PetscCheck(PetscMemTypeHost(mtype), PetscObjectComm((PetscObject)jac->schur), PETSC_ERR_SUP, "PetscMemType should be either PETSC_MEMTYPE_HOST, PETSC_MEMTYPE_CUDA, or PETSC_MEMTYPE_HIP");
1487: PetscCall(PetscFree(array));
1488: PetscCall(PetscMalloc1(m * (P + Q), &array));
1489: }
1490: PetscCall(MatCreateDenseWithMemType(PetscObjectComm((PetscObject)jac->schur), mtype, m, PETSC_DECIDE, M, P + Q, PETSC_DECIDE, array, &replace));
1491: PetscCall(MatHeaderReplace(AinvB, &replace));
1492: }
1493: PetscCall(MatCreateDenseWithMemType(PetscObjectComm((PetscObject)jac->schur), mtype, m, q, M, Q, PETSC_DECIDE, array + m * P, &C));
1494: PetscCall(MatDenseRestoreArrayAndMemType(AinvB, &array));
1495: PetscCall(MatCopy(ilinkA->X, C, SAME_NONZERO_PATTERN));
1496: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1497: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, jac->schur_user));
1498: PetscCall(MatCopy(C, ilinkA->Y, SAME_NONZERO_PATTERN)); // retrieve solutions as last columns of the composed Mat
1499: PetscCall(MatDestroy(&C));
1500: }
1501: }
1502: }
1503: if (N == P) PetscCall(KSPMatSolve(kspLower, ilinkA->X, ilinkA->Y));
1504: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->X, ilinkA->Y, NULL));
1505: PetscCall(MatMatMult(jac->C, ilinkA->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkD->X));
1506: PetscCall(MatScale(ilinkD->X, -1.0));
1507: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, ADD_VALUES, SCATTER_FORWARD));
1509: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1510: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1511: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1512: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1513: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1514: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1516: if (kspUpper == kspA) {
1517: if (!AinvB) {
1518: PetscCall(MatMatMult(jac->B, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->Y));
1519: PetscCall(MatAXPY(ilinkA->X, -1.0, ilinkA->Y, SAME_NONZERO_PATTERN));
1520: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1521: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1522: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1523: } else {
1524: PetscCall(MatMatMult(AinvB, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->X));
1525: PetscCall(MatAXPY(ilinkA->Y, 1.0, ilinkA->X, SAME_NONZERO_PATTERN));
1526: }
1527: } else {
1528: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1529: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1530: PetscCall(MatMatMult(jac->B, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->X));
1531: if (!ilinkA->Z) PetscCall(MatDuplicate(ilinkA->X, MAT_DO_NOT_COPY_VALUES, &ilinkA->Z));
1532: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->X, ilinkA->Z, NULL));
1533: PetscCall(KSPMatSolve(kspUpper, ilinkA->X, ilinkA->Z));
1534: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->X, ilinkA->Z, NULL));
1535: PetscCall(MatAXPY(ilinkA->Y, -1.0, ilinkA->Z, SAME_NONZERO_PATTERN));
1536: }
1537: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1538: }
1539: PetscFunctionReturn(PETSC_SUCCESS);
1540: }
1542: static PetscErrorCode PCApplyTranspose_FieldSplit_Schur(PC pc, Vec x, Vec y)
1543: {
1544: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1545: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1546: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1548: PetscFunctionBegin;
1549: switch (jac->schurfactorization) {
1550: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1551: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1552: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1553: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1554: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1555: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1556: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1557: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1558: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1559: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1560: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1561: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1562: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1563: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1564: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1565: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1566: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1567: PetscCall(VecScale(ilinkD->y, jac->schurscale));
1568: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1569: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1570: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1571: break;
1572: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1573: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1574: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1575: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1576: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1577: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1578: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1579: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1580: PetscCall(VecScale(ilinkD->x, -1.));
1581: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1582: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1583: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1584: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1585: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1586: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1587: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1588: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1589: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1590: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1591: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1592: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1593: break;
1594: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1595: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1596: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1597: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1598: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1599: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1600: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1601: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1602: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1603: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1604: PetscCall(VecScale(ilinkA->x, -1.));
1605: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1606: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1607: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1608: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1609: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1610: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1611: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1612: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1613: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1614: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1615: break;
1616: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1617: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1618: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1619: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1620: PetscCall(KSPSolveTranspose(kspUpper, ilinkA->x, ilinkA->y));
1621: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->y));
1622: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1623: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1624: PetscCall(VecScale(ilinkD->x, -1.0));
1625: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1626: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1628: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1629: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1630: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1631: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1632: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1633: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1634: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1636: if (kspLower == kspA) {
1637: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->y));
1638: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1639: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1640: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1641: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1642: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1643: } else {
1644: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1645: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1646: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1647: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1648: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1649: PetscCall(KSPSolveTranspose(kspLower, ilinkA->x, ilinkA->z));
1650: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->z));
1651: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1652: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1653: }
1654: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1655: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1656: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1657: }
1658: PetscFunctionReturn(PETSC_SUCCESS);
1659: }
1661: #define FieldSplitSplitSolveAdd(ilink, xx, yy) \
1662: ((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) || \
1663: 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) || \
1664: VecScatterEnd(ilink->sctx, ilink->y, yy, ADD_VALUES, SCATTER_REVERSE)))
1666: static PetscErrorCode PCApply_FieldSplit(PC pc, Vec x, Vec y)
1667: {
1668: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1669: PC_FieldSplitLink ilink = jac->head;
1670: PetscInt cnt, bs;
1672: PetscFunctionBegin;
1673: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1674: PetscBool matnest;
1676: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1677: if (jac->defaultsplit && !matnest) {
1678: PetscCall(VecGetBlockSize(x, &bs));
1679: 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);
1680: PetscCall(VecGetBlockSize(y, &bs));
1681: 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);
1682: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1683: while (ilink) {
1684: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1685: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1686: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1687: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1688: ilink = ilink->next;
1689: }
1690: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1691: } else {
1692: PetscCall(VecSet(y, 0.0));
1693: while (ilink) {
1694: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1695: ilink = ilink->next;
1696: }
1697: }
1698: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) {
1699: PetscCall(VecSet(y, 0.0));
1700: /* solve on first block for first block variables */
1701: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1702: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1703: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1704: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1705: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1706: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1707: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1708: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1710: /* compute the residual only onto second block variables using first block variables */
1711: PetscCall(MatMult(jac->Afield[1], ilink->y, ilink->next->x));
1712: ilink = ilink->next;
1713: PetscCall(VecScale(ilink->x, -1.0));
1714: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1715: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1717: /* solve on second block variables */
1718: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1719: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1720: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1721: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1722: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1723: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1724: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1725: if (!jac->w1) {
1726: PetscCall(VecDuplicate(x, &jac->w1));
1727: PetscCall(VecDuplicate(x, &jac->w2));
1728: }
1729: PetscCall(VecSet(y, 0.0));
1730: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1731: cnt = 1;
1732: while (ilink->next) {
1733: ilink = ilink->next;
1734: /* compute the residual only over the part of the vector needed */
1735: PetscCall(MatMult(jac->Afield[cnt++], y, ilink->x));
1736: PetscCall(VecScale(ilink->x, -1.0));
1737: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1738: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1739: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1740: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1741: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1742: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1743: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1744: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1745: }
1746: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1747: cnt -= 2;
1748: while (ilink->previous) {
1749: ilink = ilink->previous;
1750: /* compute the residual only over the part of the vector needed */
1751: PetscCall(MatMult(jac->Afield[cnt--], y, ilink->x));
1752: PetscCall(VecScale(ilink->x, -1.0));
1753: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1754: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1755: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1756: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1757: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1758: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1759: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1760: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1761: }
1762: }
1763: } else SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Unsupported or unknown composition %d", (int)jac->type);
1764: PetscFunctionReturn(PETSC_SUCCESS);
1765: }
1767: static PetscErrorCode PCMatApply_FieldSplit(PC pc, Mat X, Mat Y)
1768: {
1769: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1770: PC_FieldSplitLink ilink = jac->head;
1771: PetscInt cnt;
1773: PetscFunctionBegin;
1774: /* create working matrices with the correct number of columns */
1775: PetscCall(PCFieldSplitCreateWorkMats_Private(pc, X));
1776: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1777: PetscCall(MatZeroEntries(Y));
1778: while (ilink) {
1779: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, INSERT_VALUES, SCATTER_FORWARD));
1780: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1781: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1782: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1783: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1784: ilink = ilink->next;
1785: }
1786: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) {
1787: PetscCall(MatZeroEntries(Y));
1788: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, INSERT_VALUES, SCATTER_FORWARD));
1789: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1790: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1791: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1792: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1794: /* compute the residual only onto second block variables using first block variables */
1795: PetscCall(MatMatMult(jac->Afield[1], ilink->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilink->next->X));
1796: ilink = ilink->next;
1797: PetscCall(MatScale(ilink->X, -1.0));
1798: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, ADD_VALUES, SCATTER_FORWARD));
1800: /* solve on second block variables */
1801: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1802: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1803: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1804: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1805: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1806: /* general multiplicative with any number of splits */
1807: PetscCall(MatZeroEntries(Y));
1808: /* first split */
1809: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, INSERT_VALUES, SCATTER_FORWARD));
1810: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1811: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1812: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1813: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1814: cnt = 1;
1815: /* forward sweep */
1816: while (ilink->next) {
1817: ilink = ilink->next;
1818: /* compute the residual only over the part of the vector needed */
1819: PetscCall(MatMatMult(jac->Afield[cnt++], Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilink->X));
1820: PetscCall(MatScale(ilink->X, -1.0));
1821: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, ADD_VALUES, SCATTER_FORWARD));
1822: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1823: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1824: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1825: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1826: }
1827: /* backward sweep for symmetric multiplicative */
1828: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1829: cnt -= 2;
1830: while (ilink->previous) {
1831: ilink = ilink->previous;
1832: /* compute the residual only over the part of the vector needed */
1833: PetscCall(MatMatMult(jac->Afield[cnt--], Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilink->X));
1834: PetscCall(MatScale(ilink->X, -1.0));
1835: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, ADD_VALUES, SCATTER_FORWARD));
1836: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1837: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1838: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1839: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1840: }
1841: }
1842: } else SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "PCMatApply() not implemented for this fieldsplit type");
1843: PetscFunctionReturn(PETSC_SUCCESS);
1844: }
1846: static PetscErrorCode PCApply_FieldSplit_GKB(PC pc, Vec x, Vec y)
1847: {
1848: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1849: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1850: KSP ksp = ilinkA->ksp;
1851: Vec u, v, Hu, d, work1, work2;
1852: PetscScalar alpha, z, nrmz2, *vecz;
1853: PetscReal lowbnd, nu, beta;
1854: PetscInt j, iterGKB;
1856: PetscFunctionBegin;
1857: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1858: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1859: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1860: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1862: u = jac->u;
1863: v = jac->v;
1864: Hu = jac->Hu;
1865: d = jac->d;
1866: work1 = jac->w1;
1867: work2 = jac->w2;
1868: vecz = jac->vecz;
1870: /* Change RHS to comply with matrix regularization H = A + nu*B*B' */
1871: /* Add q = q + nu*B*b */
1872: if (jac->gkbnu) {
1873: nu = jac->gkbnu;
1874: PetscCall(VecScale(ilinkD->x, jac->gkbnu));
1875: PetscCall(MatMultAdd(jac->B, ilinkD->x, ilinkA->x, ilinkA->x)); /* q = q + nu*B*b */
1876: } else {
1877: /* Situation when no augmented Lagrangian is used. Then we set inner */
1878: /* matrix N = I in [Ar13], and thus nu = 1. */
1879: nu = 1;
1880: }
1882: /* Transform rhs from [q,tilde{b}] to [0,b] */
1883: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1884: PetscCall(KSPSolve(ksp, ilinkA->x, ilinkA->y));
1885: PetscCall(KSPCheckSolve(ksp, pc, ilinkA->y));
1886: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1887: PetscCall(MatMultHermitianTranspose(jac->B, ilinkA->y, work1));
1888: PetscCall(VecAXPBY(work1, 1.0 / nu, -1.0, ilinkD->x)); /* c = b - B'*x */
1890: /* First step of algorithm */
1891: PetscCall(VecNorm(work1, NORM_2, &beta)); /* beta = sqrt(nu*c'*c)*/
1892: KSPCheckDot(ksp, beta);
1893: beta = PetscSqrtReal(nu) * beta;
1894: PetscCall(VecAXPBY(v, nu / beta, 0.0, work1)); /* v = nu/beta *c */
1895: PetscCall(MatMult(jac->B, v, work2)); /* u = H^{-1}*B*v */
1896: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1897: PetscCall(KSPSolve(ksp, work2, u));
1898: PetscCall(KSPCheckSolve(ksp, pc, u));
1899: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1900: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1901: PetscCall(VecDot(Hu, u, &alpha));
1902: KSPCheckDot(ksp, alpha);
1903: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1904: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1905: PetscCall(VecScale(u, 1.0 / alpha));
1906: PetscCall(VecAXPBY(d, 1.0 / alpha, 0.0, v)); /* v = nu/beta *c */
1908: z = beta / alpha;
1909: vecz[1] = z;
1911: /* Computation of first iterate x(1) and p(1) */
1912: PetscCall(VecAXPY(ilinkA->y, z, u));
1913: PetscCall(VecCopy(d, ilinkD->y));
1914: PetscCall(VecScale(ilinkD->y, -z));
1916: iterGKB = 1;
1917: lowbnd = 2 * jac->gkbtol;
1918: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1920: while (iterGKB < jac->gkbmaxit && lowbnd > jac->gkbtol) {
1921: iterGKB += 1;
1922: PetscCall(MatMultHermitianTranspose(jac->B, u, work1)); /* v <- nu*(B'*u-alpha/nu*v) */
1923: PetscCall(VecAXPBY(v, nu, -alpha, work1));
1924: PetscCall(VecNorm(v, NORM_2, &beta)); /* beta = sqrt(nu)*v'*v */
1925: beta = beta / PetscSqrtReal(nu);
1926: PetscCall(VecScale(v, 1.0 / beta));
1927: PetscCall(MatMult(jac->B, v, work2)); /* u <- H^{-1}*(B*v-beta*H*u) */
1928: PetscCall(MatMult(jac->H, u, Hu));
1929: PetscCall(VecAXPY(work2, -beta, Hu));
1930: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1931: PetscCall(KSPSolve(ksp, work2, u));
1932: PetscCall(KSPCheckSolve(ksp, pc, u));
1933: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1934: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1935: PetscCall(VecDot(Hu, u, &alpha));
1936: KSPCheckDot(ksp, alpha);
1937: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1938: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1939: PetscCall(VecScale(u, 1.0 / alpha));
1941: z = -beta / alpha * z; /* z <- beta/alpha*z */
1942: vecz[0] = z;
1944: /* Computation of new iterate x(i+1) and p(i+1) */
1945: PetscCall(VecAXPBY(d, 1.0 / alpha, -beta / alpha, v)); /* d = (v-beta*d)/alpha */
1946: PetscCall(VecAXPY(ilinkA->y, z, u)); /* r = r + z*u */
1947: PetscCall(VecAXPY(ilinkD->y, -z, d)); /* p = p - z*d */
1948: PetscCall(MatMult(jac->H, ilinkA->y, Hu)); /* ||u||_H = u'*H*u */
1949: PetscCall(VecDot(Hu, ilinkA->y, &nrmz2));
1951: /* Compute Lower Bound estimate */
1952: if (iterGKB > jac->gkbdelay) {
1953: lowbnd = 0.0;
1954: for (j = 0; j < jac->gkbdelay; j++) lowbnd += PetscAbsScalar(vecz[j] * vecz[j]);
1955: lowbnd = PetscSqrtReal(lowbnd / PetscAbsScalar(nrmz2));
1956: }
1958: for (j = 0; j < jac->gkbdelay - 1; j++) vecz[jac->gkbdelay - j - 1] = vecz[jac->gkbdelay - j - 2];
1959: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1960: }
1962: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1963: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1964: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1965: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1966: PetscFunctionReturn(PETSC_SUCCESS);
1967: }
1969: #define FieldSplitSplitSolveAddTranspose(ilink, xx, yy) \
1970: ((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) || \
1971: 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) || \
1972: VecScatterEnd(ilink->sctx, ilink->x, yy, ADD_VALUES, SCATTER_REVERSE)))
1974: static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc, Vec x, Vec y)
1975: {
1976: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1977: PC_FieldSplitLink ilink = jac->head;
1978: PetscInt bs;
1980: PetscFunctionBegin;
1981: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1982: PetscBool matnest;
1984: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1985: if (jac->defaultsplit && !matnest) {
1986: PetscCall(VecGetBlockSize(x, &bs));
1987: 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);
1988: PetscCall(VecGetBlockSize(y, &bs));
1989: 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);
1990: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1991: while (ilink) {
1992: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1993: PetscCall(KSPSolveTranspose(ilink->ksp, ilink->x, ilink->y));
1994: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1995: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1996: ilink = ilink->next;
1997: }
1998: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1999: } else {
2000: PetscCall(VecSet(y, 0.0));
2001: while (ilink) {
2002: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
2003: ilink = ilink->next;
2004: }
2005: }
2006: } else {
2007: if (!jac->w1) {
2008: PetscCall(VecDuplicate(x, &jac->w1));
2009: PetscCall(VecDuplicate(x, &jac->w2));
2010: }
2011: PetscCall(VecSet(y, 0.0));
2012: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
2013: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
2014: while (ilink->next) {
2015: ilink = ilink->next;
2016: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
2017: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
2018: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
2019: }
2020: while (ilink->previous) {
2021: ilink = ilink->previous;
2022: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
2023: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
2024: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
2025: }
2026: } else {
2027: while (ilink->next) { /* get to last entry in linked list */
2028: ilink = ilink->next;
2029: }
2030: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
2031: while (ilink->previous) {
2032: ilink = ilink->previous;
2033: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
2034: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
2035: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
2036: }
2037: }
2038: }
2039: PetscFunctionReturn(PETSC_SUCCESS);
2040: }
2042: static PetscErrorCode PCReset_FieldSplit(PC pc)
2043: {
2044: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2045: PC_FieldSplitLink ilink = jac->head, next;
2047: PetscFunctionBegin;
2048: while (ilink) {
2049: PetscCall(KSPDestroy(&ilink->ksp));
2050: PetscCall(VecDestroy(&ilink->x));
2051: PetscCall(VecDestroy(&ilink->y));
2052: PetscCall(VecDestroy(&ilink->z));
2053: PetscCall(MatDestroy(&ilink->X));
2054: PetscCall(MatDestroy(&ilink->Y));
2055: PetscCall(MatDestroy(&ilink->Z));
2056: PetscCall(VecScatterDestroy(&ilink->sctx));
2057: PetscCall(ISDestroy(&ilink->is));
2058: PetscCall(ISDestroy(&ilink->is_col));
2059: PetscCall(PetscFree(ilink->splitname));
2060: PetscCall(PetscFree(ilink->fields));
2061: PetscCall(PetscFree(ilink->fields_col));
2062: next = ilink->next;
2063: PetscCall(PetscFree(ilink));
2064: ilink = next;
2065: }
2066: jac->head = NULL;
2067: PetscCall(PetscFree2(jac->x, jac->y));
2068: if (jac->mat && jac->mat != jac->pmat) {
2069: PetscCall(MatDestroyMatrices(jac->nsplits, &jac->mat));
2070: } else if (jac->mat) {
2071: jac->mat = NULL;
2072: }
2073: if (jac->pmat) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->pmat));
2074: if (jac->Afield) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->Afield));
2075: jac->nsplits = 0;
2076: PetscCall(VecDestroy(&jac->w1));
2077: PetscCall(VecDestroy(&jac->w2));
2078: if (jac->schur) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", NULL));
2079: PetscCall(MatDestroy(&jac->schur));
2080: PetscCall(MatDestroy(&jac->schurp));
2081: PetscCall(MatDestroy(&jac->schur_user));
2082: PetscCall(KSPDestroy(&jac->kspschur));
2083: PetscCall(KSPDestroy(&jac->kspupper));
2084: PetscCall(MatDestroy(&jac->B));
2085: PetscCall(MatDestroy(&jac->C));
2086: PetscCall(MatDestroy(&jac->H));
2087: PetscCall(VecDestroy(&jac->u));
2088: PetscCall(VecDestroy(&jac->v));
2089: PetscCall(VecDestroy(&jac->Hu));
2090: PetscCall(VecDestroy(&jac->d));
2091: PetscCall(PetscFree(jac->vecz));
2092: PetscCall(PetscViewerDestroy(&jac->gkbviewer));
2093: jac->isrestrict = PETSC_FALSE;
2094: PetscFunctionReturn(PETSC_SUCCESS);
2095: }
2097: static PetscErrorCode PCDestroy_FieldSplit(PC pc)
2098: {
2099: PetscFunctionBegin;
2100: PetscCall(PCReset_FieldSplit(pc));
2101: PetscCall(PetscFree(pc->data));
2102: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", NULL));
2103: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", NULL));
2104: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", NULL));
2105: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", NULL));
2106: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", NULL));
2107: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", NULL));
2108: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", NULL));
2109: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
2110: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
2111: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
2112: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
2113: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
2114: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
2115: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
2116: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
2117: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
2118: PetscFunctionReturn(PETSC_SUCCESS);
2119: }
2121: static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc, PetscOptionItems PetscOptionsObject)
2122: {
2123: PetscInt bs;
2124: PetscBool flg;
2125: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2126: PCCompositeType ctype;
2128: PetscFunctionBegin;
2129: PetscOptionsHeadBegin(PetscOptionsObject, "FieldSplit options");
2130: PetscCall(PetscOptionsBool("-pc_fieldsplit_dm_splits", "Whether to use DMCreateFieldDecomposition() for splits", "PCFieldSplitSetDMSplits", jac->dm_splits, &jac->dm_splits, NULL));
2131: PetscCall(PetscOptionsInt("-pc_fieldsplit_block_size", "Blocksize that defines number of fields", "PCFieldSplitSetBlockSize", jac->bs, &bs, &flg));
2132: if (flg) PetscCall(PCFieldSplitSetBlockSize(pc, bs));
2133: jac->diag_use_amat = pc->useAmat;
2134: 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));
2135: jac->offdiag_use_amat = pc->useAmat;
2136: 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));
2137: PetscCall(PetscOptionsBool("-pc_fieldsplit_detect_saddle_point", "Form 2-way split by detecting zero diagonal entries", "PCFieldSplitSetDetectSaddlePoint", jac->detect, &jac->detect, NULL));
2138: PetscCall(PCFieldSplitSetDetectSaddlePoint(pc, jac->detect)); /* Sets split type and Schur PC type */
2139: PetscCall(PetscOptionsEnum("-pc_fieldsplit_type", "Type of composition", "PCFieldSplitSetType", PCCompositeTypes, (PetscEnum)jac->type, (PetscEnum *)&ctype, &flg));
2140: if (flg) PetscCall(PCFieldSplitSetType(pc, ctype));
2141: /* Only setup fields once */
2142: if (jac->bs > 0 && jac->nsplits == 0) {
2143: /* only allow user to set fields from command line.
2144: otherwise user can set them in PCFieldSplitSetDefaults() */
2145: PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc));
2146: if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n"));
2147: }
2148: if (jac->type == PC_COMPOSITE_SCHUR) {
2149: PetscCall(PetscOptionsGetEnum(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_schur_factorization_type", PCFieldSplitSchurFactTypes, (PetscEnum *)&jac->schurfactorization, &flg));
2150: if (flg) PetscCall(PetscInfo(pc, "Deprecated use of -pc_fieldsplit_schur_factorization_type\n"));
2151: 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));
2152: PetscCall(PetscOptionsEnum("-pc_fieldsplit_schur_precondition", "How to build preconditioner for Schur complement", "PCFieldSplitSetSchurPre", PCFieldSplitSchurPreTypes, (PetscEnum)jac->schurpre, (PetscEnum *)&jac->schurpre, NULL));
2153: PetscCall(PetscOptionsScalar("-pc_fieldsplit_schur_scale", "Scale Schur complement", "PCFieldSplitSetSchurScale", jac->schurscale, &jac->schurscale, NULL));
2154: } else if (jac->type == PC_COMPOSITE_GKB) {
2155: PetscCall(PetscOptionsReal("-pc_fieldsplit_gkb_tol", "The tolerance for the lower bound stopping criterion", "PCFieldSplitSetGKBTol", jac->gkbtol, &jac->gkbtol, NULL));
2156: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_delay", "The delay value for lower bound criterion", "PCFieldSplitSetGKBDelay", jac->gkbdelay, &jac->gkbdelay, NULL));
2157: PetscCall(PetscOptionsBoundedReal("-pc_fieldsplit_gkb_nu", "Parameter in augmented Lagrangian approach", "PCFieldSplitSetGKBNu", jac->gkbnu, &jac->gkbnu, NULL, 0.0));
2158: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_maxit", "Maximum allowed number of iterations", "PCFieldSplitSetGKBMaxit", jac->gkbmaxit, &jac->gkbmaxit, NULL));
2159: PetscCall(PetscOptionsBool("-pc_fieldsplit_gkb_monitor", "Prints number of GKB iterations and error", "PCFieldSplitGKB", jac->gkbmonitor, &jac->gkbmonitor, NULL));
2160: }
2161: /*
2162: In the initial call to this routine the sub-solver data structures do not exist so we cannot call KSPSetFromOptions() on them yet.
2163: 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
2164: is called on the outer solver in case changes were made in the options database
2166: 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()
2167: 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.
2168: Without this extra check test p2p1fetidp_olof_full and others fail with incorrect matrix types.
2170: There could be a negative side effect of calling the KSPSetFromOptions() below.
2172: If one captured the PetscObjectState of the options database one could skip these calls if the database has not changed from the previous call
2173: */
2174: if (jac->issetup) {
2175: PC_FieldSplitLink ilink = jac->head;
2176: if (jac->type == PC_COMPOSITE_SCHUR) {
2177: if (jac->kspupper && jac->kspupper->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspupper));
2178: if (jac->kspschur && jac->kspschur->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspschur));
2179: }
2180: while (ilink) {
2181: if (ilink->ksp->totalits > 0) PetscCall(KSPSetFromOptions(ilink->ksp));
2182: ilink = ilink->next;
2183: }
2184: }
2185: PetscOptionsHeadEnd();
2186: PetscFunctionReturn(PETSC_SUCCESS);
2187: }
2189: static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc, const char splitname[], PetscInt n, const PetscInt *fields, const PetscInt *fields_col)
2190: {
2191: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2192: PC_FieldSplitLink ilink, next = jac->head;
2193: char prefix[128];
2194: PetscInt i;
2195: PetscLogEvent nse;
2197: PetscFunctionBegin;
2198: if (jac->splitdefined) {
2199: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
2200: PetscFunctionReturn(PETSC_SUCCESS);
2201: }
2202: for (i = 0; i < n; i++) PetscCheck(fields[i] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", fields[i]);
2203: PetscCall(PetscNew(&ilink));
2204: if (splitname) {
2205: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
2206: } else {
2207: PetscCall(PetscMalloc1(3, &ilink->splitname));
2208: PetscCall(PetscSNPrintf(ilink->splitname, 2, "%" PetscInt_FMT, jac->nsplits));
2209: }
2210: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
2211: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
2212: PetscCall(PetscMalloc1(n, &ilink->fields));
2213: PetscCall(PetscArraycpy(ilink->fields, fields, n));
2214: PetscCall(PetscMalloc1(n, &ilink->fields_col));
2215: PetscCall(PetscArraycpy(ilink->fields_col, fields_col, n));
2217: ilink->nfields = n;
2218: ilink->next = NULL;
2219: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
2220: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
2221: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
2222: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
2223: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
2225: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
2226: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
2228: if (!next) {
2229: jac->head = ilink;
2230: ilink->previous = NULL;
2231: } else {
2232: while (next->next) next = next->next;
2233: next->next = ilink;
2234: ilink->previous = next;
2235: }
2236: jac->nsplits++;
2237: PetscFunctionReturn(PETSC_SUCCESS);
2238: }
2240: static PetscErrorCode PCFieldSplitSchurGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
2241: {
2242: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2244: PetscFunctionBegin;
2245: *subksp = NULL;
2246: if (n) *n = 0;
2247: if (jac->type == PC_COMPOSITE_SCHUR) {
2248: PetscInt nn;
2250: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitSchurGetSubKSP()");
2251: PetscCheck(jac->nsplits == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unexpected number of splits %" PetscInt_FMT " != 2", jac->nsplits);
2252: nn = jac->nsplits + (jac->kspupper != jac->head->ksp ? 1 : 0);
2253: PetscCall(PetscMalloc1(nn, subksp));
2254: (*subksp)[0] = jac->head->ksp;
2255: (*subksp)[1] = jac->kspschur;
2256: if (jac->kspupper != jac->head->ksp) (*subksp)[2] = jac->kspupper;
2257: if (n) *n = nn;
2258: }
2259: PetscFunctionReturn(PETSC_SUCCESS);
2260: }
2262: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc, PetscInt *n, KSP **subksp)
2263: {
2264: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2266: PetscFunctionBegin;
2267: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitGetSubKSP()");
2268: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2269: PetscCall(MatSchurComplementGetKSP(jac->schur, *subksp));
2271: (*subksp)[1] = jac->kspschur;
2272: if (n) *n = jac->nsplits;
2273: PetscFunctionReturn(PETSC_SUCCESS);
2274: }
2276: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
2277: {
2278: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2279: PetscInt cnt = 0;
2280: PC_FieldSplitLink ilink = jac->head;
2282: PetscFunctionBegin;
2283: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2284: while (ilink) {
2285: (*subksp)[cnt++] = ilink->ksp;
2286: ilink = ilink->next;
2287: }
2288: 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);
2289: if (n) *n = jac->nsplits;
2290: PetscFunctionReturn(PETSC_SUCCESS);
2291: }
2293: /*@
2294: PCFieldSplitRestrictIS - Restricts the fieldsplit `IS`s to be within a given `IS`.
2296: Input Parameters:
2297: + pc - the preconditioner context
2298: - isy - the index set that defines the indices to which the fieldsplit is to be restricted
2300: Level: advanced
2302: Developer Notes:
2303: It seems the resulting `IS`s will not cover the entire space, so
2304: how can they define a convergent preconditioner? Needs explaining.
2306: .seealso: [](sec_block_matrices), `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2307: @*/
2308: PetscErrorCode PCFieldSplitRestrictIS(PC pc, IS isy)
2309: {
2310: PetscFunctionBegin;
2313: PetscTryMethod(pc, "PCFieldSplitRestrictIS_C", (PC, IS), (pc, isy));
2314: PetscFunctionReturn(PETSC_SUCCESS);
2315: }
2317: static PetscErrorCode PCFieldSplitRestrictIS_FieldSplit(PC pc, IS isy)
2318: {
2319: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2320: PC_FieldSplitLink ilink = jac->head, next;
2321: PetscInt localsize, size, sizez, i;
2322: const PetscInt *ind, *indz;
2323: PetscInt *indc, *indcz;
2324: PetscBool flg;
2326: PetscFunctionBegin;
2327: PetscCall(ISGetLocalSize(isy, &localsize));
2328: PetscCallMPI(MPI_Scan(&localsize, &size, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)isy)));
2329: size -= localsize;
2330: while (ilink) {
2331: IS isrl, isr;
2332: PC subpc;
2333: PetscCall(ISEmbed(ilink->is, isy, PETSC_TRUE, &isrl));
2334: PetscCall(ISGetLocalSize(isrl, &localsize));
2335: PetscCall(PetscMalloc1(localsize, &indc));
2336: PetscCall(ISGetIndices(isrl, &ind));
2337: PetscCall(PetscArraycpy(indc, ind, localsize));
2338: PetscCall(ISRestoreIndices(isrl, &ind));
2339: PetscCall(ISDestroy(&isrl));
2340: for (i = 0; i < localsize; i++) *(indc + i) += size;
2341: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)isy), localsize, indc, PETSC_OWN_POINTER, &isr));
2342: PetscCall(PetscObjectReference((PetscObject)isr));
2343: PetscCall(ISDestroy(&ilink->is));
2344: ilink->is = isr;
2345: PetscCall(PetscObjectReference((PetscObject)isr));
2346: PetscCall(ISDestroy(&ilink->is_col));
2347: ilink->is_col = isr;
2348: PetscCall(ISDestroy(&isr));
2349: PetscCall(KSPGetPC(ilink->ksp, &subpc));
2350: PetscCall(PetscObjectTypeCompare((PetscObject)subpc, PCFIELDSPLIT, &flg));
2351: if (flg) {
2352: IS iszl, isz;
2353: MPI_Comm comm;
2354: PetscCall(ISGetLocalSize(ilink->is, &localsize));
2355: comm = PetscObjectComm((PetscObject)ilink->is);
2356: PetscCall(ISEmbed(isy, ilink->is, PETSC_TRUE, &iszl));
2357: PetscCallMPI(MPI_Scan(&localsize, &sizez, 1, MPIU_INT, MPI_SUM, comm));
2358: sizez -= localsize;
2359: PetscCall(ISGetLocalSize(iszl, &localsize));
2360: PetscCall(PetscMalloc1(localsize, &indcz));
2361: PetscCall(ISGetIndices(iszl, &indz));
2362: PetscCall(PetscArraycpy(indcz, indz, localsize));
2363: PetscCall(ISRestoreIndices(iszl, &indz));
2364: PetscCall(ISDestroy(&iszl));
2365: for (i = 0; i < localsize; i++) *(indcz + i) += sizez;
2366: PetscCall(ISCreateGeneral(comm, localsize, indcz, PETSC_OWN_POINTER, &isz));
2367: PetscCall(PCFieldSplitRestrictIS(subpc, isz));
2368: PetscCall(ISDestroy(&isz));
2369: }
2370: next = ilink->next;
2371: ilink = next;
2372: }
2373: jac->isrestrict = PETSC_TRUE;
2374: PetscFunctionReturn(PETSC_SUCCESS);
2375: }
2377: static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc, const char splitname[], IS is)
2378: {
2379: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2380: PC_FieldSplitLink ilink, next = jac->head;
2381: char prefix[128];
2382: PetscLogEvent nse;
2384: PetscFunctionBegin;
2385: if (jac->splitdefined) {
2386: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
2387: PetscFunctionReturn(PETSC_SUCCESS);
2388: }
2389: PetscCall(PetscNew(&ilink));
2390: if (splitname) {
2391: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
2392: } else {
2393: PetscCall(PetscMalloc1(8, &ilink->splitname));
2394: PetscCall(PetscSNPrintf(ilink->splitname, 7, "%" PetscInt_FMT, jac->nsplits));
2395: }
2396: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
2397: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
2398: PetscCall(PetscObjectReference((PetscObject)is));
2399: PetscCall(ISDestroy(&ilink->is));
2400: ilink->is = is;
2401: PetscCall(PetscObjectReference((PetscObject)is));
2402: PetscCall(ISDestroy(&ilink->is_col));
2403: ilink->is_col = is;
2404: ilink->next = NULL;
2405: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
2406: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
2407: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
2408: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
2409: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
2411: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
2412: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
2414: if (!next) {
2415: jac->head = ilink;
2416: ilink->previous = NULL;
2417: } else {
2418: while (next->next) next = next->next;
2419: next->next = ilink;
2420: ilink->previous = next;
2421: }
2422: jac->nsplits++;
2423: PetscFunctionReturn(PETSC_SUCCESS);
2424: }
2426: /*@
2427: PCFieldSplitSetFields - Sets the fields that define one particular split in `PCFIELDSPLIT`
2429: Logically Collective
2431: Input Parameters:
2432: + pc - the preconditioner context
2433: . splitname - name of this split, if `NULL` the number of the split is used
2434: . n - the number of fields in this split
2435: . fields - the fields in this split
2436: - 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
2437: of the matrix and `fields_col` provides the column indices for that block
2439: Options Database Key:
2440: . -pc_fieldsplit_%d_fields a,b,... - indicates the fields to be used in the `%d`'th split
2442: Level: intermediate
2444: Notes:
2445: Use `PCFieldSplitSetIS()` to set a general set of indices as a split.
2447: If the matrix used to construct the preconditioner is `MATNEST` then field i refers to the `is_row[i]` `IS` passed to `MatCreateNest()`.
2449: If the matrix used to construct the preconditioner is not `MATNEST` then
2450: `PCFieldSplitSetFields()` is for defining fields as strided blocks (based on the block size provided to the matrix with `MatSetBlockSize()` or
2451: to the `PC` with `PCFieldSplitSetBlockSize()`). For example, if the block
2452: 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
2453: 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x23x56x8.. x12x45x78x....
2454: where the numbered entries indicate what is in the split.
2456: This function is called once per split (it creates a new split each time). Solve options
2457: for this split will be available under the prefix `-fieldsplit_SPLITNAME_`.
2459: `PCFieldSplitSetIS()` does not support having a `fields_col` different from `fields`
2461: Developer Notes:
2462: This routine does not actually create the `IS` representing the split, that is delayed
2463: until `PCSetUp_FieldSplit()`, because information about the vector/matrix layouts may not be
2464: available when this routine is called.
2466: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetIS()`, `PCFieldSplitRestrictIS()`,
2467: `MatSetBlockSize()`, `MatCreateNest()`
2468: @*/
2469: PetscErrorCode PCFieldSplitSetFields(PC pc, const char splitname[], PetscInt n, const PetscInt fields[], const PetscInt fields_col[])
2470: {
2471: PetscFunctionBegin;
2473: PetscAssertPointer(splitname, 2);
2474: PetscCheck(n >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Provided number of fields %" PetscInt_FMT " in split \"%s\" not positive", n, splitname);
2475: PetscAssertPointer(fields, 4);
2476: PetscTryMethod(pc, "PCFieldSplitSetFields_C", (PC, const char[], PetscInt, const PetscInt *, const PetscInt *), (pc, splitname, n, fields, fields_col));
2477: PetscFunctionReturn(PETSC_SUCCESS);
2478: }
2480: /*@
2481: PCFieldSplitSetDiagUseAmat - set flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2482: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2484: Logically Collective
2486: Input Parameters:
2487: + pc - the preconditioner object
2488: - flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2490: Options Database Key:
2491: . -pc_fieldsplit_diag_use_amat - use the Amat to provide the diagonal blocks
2493: Level: intermediate
2495: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetDiagUseAmat()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFIELDSPLIT`
2496: @*/
2497: PetscErrorCode PCFieldSplitSetDiagUseAmat(PC pc, PetscBool flg)
2498: {
2499: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2500: PetscBool isfs;
2502: PetscFunctionBegin;
2504: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2505: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2506: jac->diag_use_amat = flg;
2507: PetscFunctionReturn(PETSC_SUCCESS);
2508: }
2510: /*@
2511: PCFieldSplitGetDiagUseAmat - get the flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2512: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2514: Logically Collective
2516: Input Parameter:
2517: . pc - the preconditioner object
2519: Output Parameter:
2520: . flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2522: Level: intermediate
2524: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetDiagUseAmat()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFIELDSPLIT`
2525: @*/
2526: PetscErrorCode PCFieldSplitGetDiagUseAmat(PC pc, PetscBool *flg)
2527: {
2528: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2529: PetscBool isfs;
2531: PetscFunctionBegin;
2533: PetscAssertPointer(flg, 2);
2534: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2535: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2536: *flg = jac->diag_use_amat;
2537: PetscFunctionReturn(PETSC_SUCCESS);
2538: }
2540: /*@
2541: PCFieldSplitSetOffDiagUseAmat - set flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2542: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2544: Logically Collective
2546: Input Parameters:
2547: + pc - the preconditioner object
2548: - flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2550: Options Database Key:
2551: . -pc_fieldsplit_off_diag_use_amat (true|false) - use the Amat to extract the off-diagonal blocks
2553: Level: intermediate
2555: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFieldSplitSetDiagUseAmat()`, `PCFIELDSPLIT`
2556: @*/
2557: PetscErrorCode PCFieldSplitSetOffDiagUseAmat(PC pc, PetscBool flg)
2558: {
2559: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2560: PetscBool isfs;
2562: PetscFunctionBegin;
2564: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2565: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2566: jac->offdiag_use_amat = flg;
2567: PetscFunctionReturn(PETSC_SUCCESS);
2568: }
2570: /*@
2571: PCFieldSplitGetOffDiagUseAmat - get the flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2572: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2574: Logically Collective
2576: Input Parameter:
2577: . pc - the preconditioner object
2579: Output Parameter:
2580: . flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2582: Level: intermediate
2584: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFieldSplitGetDiagUseAmat()`, `PCFIELDSPLIT`
2585: @*/
2586: PetscErrorCode PCFieldSplitGetOffDiagUseAmat(PC pc, PetscBool *flg)
2587: {
2588: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2589: PetscBool isfs;
2591: PetscFunctionBegin;
2593: PetscAssertPointer(flg, 2);
2594: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2595: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2596: *flg = jac->offdiag_use_amat;
2597: PetscFunctionReturn(PETSC_SUCCESS);
2598: }
2600: /*@
2601: PCFieldSplitSetIS - Sets the exact elements for a split in a `PCFIELDSPLIT`
2603: Logically Collective
2605: Input Parameters:
2606: + pc - the preconditioner context
2607: . splitname - name of this split, if `NULL` the number of the split is used
2608: - is - the index set that defines the elements in this split
2610: Level: intermediate
2612: Notes:
2613: Use `PCFieldSplitSetFields()`, for splits defined by strided `IS` based on the matrix block size or the `is_rows[]` passed into `MATNEST`
2615: This function is called once per split (it creates a new split each time). Solve options
2616: for this split will be available under the prefix -fieldsplit_SPLITNAME_.
2618: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetFields()`
2619: @*/
2620: PetscErrorCode PCFieldSplitSetIS(PC pc, const char splitname[], IS is)
2621: {
2622: PetscFunctionBegin;
2624: if (splitname) PetscAssertPointer(splitname, 2);
2626: PetscTryMethod(pc, "PCFieldSplitSetIS_C", (PC, const char[], IS), (pc, splitname, is));
2627: PetscFunctionReturn(PETSC_SUCCESS);
2628: }
2630: /*@
2631: PCFieldSplitGetIS - Retrieves the elements for a split as an `IS`
2633: Logically Collective
2635: Input Parameters:
2636: + pc - the preconditioner context
2637: - splitname - name of this split
2639: Output Parameter:
2640: . is - the index set that defines the elements in this split, or `NULL` if the split is not found
2642: Level: intermediate
2644: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetIS()`, `PCFieldSplitGetISByIndex()`
2645: @*/
2646: PetscErrorCode PCFieldSplitGetIS(PC pc, const char splitname[], IS *is)
2647: {
2648: PetscFunctionBegin;
2650: PetscAssertPointer(splitname, 2);
2651: PetscAssertPointer(is, 3);
2652: {
2653: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2654: PC_FieldSplitLink ilink = jac->head;
2655: PetscBool found;
2657: *is = NULL;
2658: while (ilink) {
2659: PetscCall(PetscStrcmp(ilink->splitname, splitname, &found));
2660: if (found) {
2661: *is = ilink->is;
2662: break;
2663: }
2664: ilink = ilink->next;
2665: }
2666: }
2667: PetscFunctionReturn(PETSC_SUCCESS);
2668: }
2670: /*@
2671: PCFieldSplitGetISByIndex - Retrieves the elements for a given split as an `IS`
2673: Logically Collective
2675: Input Parameters:
2676: + pc - the preconditioner context
2677: - index - index of this split
2679: Output Parameter:
2680: . is - the index set that defines the elements in this split
2682: Level: intermediate
2684: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitGetIS()`, `PCFieldSplitSetIS()`
2685: @*/
2686: PetscErrorCode PCFieldSplitGetISByIndex(PC pc, PetscInt index, IS *is)
2687: {
2688: PetscFunctionBegin;
2689: PetscCheck(index >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", index);
2691: PetscAssertPointer(is, 3);
2692: {
2693: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2694: PC_FieldSplitLink ilink = jac->head;
2695: PetscInt i = 0;
2696: PetscCheck(index < jac->nsplits, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " requested but only %" PetscInt_FMT " exist", index, jac->nsplits);
2698: while (i < index) {
2699: ilink = ilink->next;
2700: ++i;
2701: }
2702: PetscCall(PCFieldSplitGetIS(pc, ilink->splitname, is));
2703: }
2704: PetscFunctionReturn(PETSC_SUCCESS);
2705: }
2707: /*@
2708: PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the
2709: fieldsplit preconditioner when calling `PCFieldSplitSetFields()`. If not set the matrix block size is used.
2711: Logically Collective
2713: Input Parameters:
2714: + pc - the preconditioner context
2715: - bs - the block size
2717: Level: intermediate
2719: Note:
2720: If the matrix is a `MATNEST` then the `is_rows[]` passed to `MatCreateNest()` determines the fields.
2722: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2723: @*/
2724: PetscErrorCode PCFieldSplitSetBlockSize(PC pc, PetscInt bs)
2725: {
2726: PetscFunctionBegin;
2729: PetscTryMethod(pc, "PCFieldSplitSetBlockSize_C", (PC, PetscInt), (pc, bs));
2730: PetscFunctionReturn(PETSC_SUCCESS);
2731: }
2733: /*@C
2734: PCFieldSplitGetSubKSP - Gets the `KSP` contexts for all splits
2736: Collective
2738: Input Parameter:
2739: . pc - the preconditioner context
2741: Output Parameters:
2742: + n - the number of splits
2743: - subksp - the array of `KSP` contexts
2745: Level: advanced
2747: Notes:
2748: After `PCFieldSplitGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2749: (not the `KSP`, just the array that contains them).
2751: You must call `PCSetUp()` before calling `PCFieldSplitGetSubKSP()`.
2753: If the fieldsplit is of type `PC_COMPOSITE_SCHUR`, it returns the `KSP` object used inside the
2754: Schur complement and the `KSP` object used to iterate over the Schur complement.
2755: To access all the `KSP` objects used in `PC_COMPOSITE_SCHUR`, use `PCFieldSplitSchurGetSubKSP()`.
2757: If the fieldsplit is of type `PC_COMPOSITE_GKB`, it returns the `KSP` object used to solve the
2758: inner linear system defined by the matrix H in each loop.
2760: Fortran Note:
2761: Call `PCFieldSplitRestoreSubKSP()` when the array of `KSP` is no longer needed
2763: Developer Notes:
2764: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2766: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitSchurGetSubKSP()`
2767: @*/
2768: PetscErrorCode PCFieldSplitGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2769: {
2770: PetscFunctionBegin;
2772: if (n) PetscAssertPointer(n, 2);
2773: PetscUseMethod(pc, "PCFieldSplitGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2774: PetscFunctionReturn(PETSC_SUCCESS);
2775: }
2777: /*@C
2778: PCFieldSplitSchurGetSubKSP - Gets the `KSP` contexts used inside the Schur complement based `PCFIELDSPLIT`
2780: Collective
2782: Input Parameter:
2783: . pc - the preconditioner context
2785: Output Parameters:
2786: + n - the number of splits
2787: - subksp - the array of `KSP` contexts
2789: Level: advanced
2791: Notes:
2792: After `PCFieldSplitSchurGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2793: (not the `KSP` just the array that contains them).
2795: You must call `PCSetUp()` before calling `PCFieldSplitSchurGetSubKSP()`.
2797: If the fieldsplit type is of type `PC_COMPOSITE_SCHUR`, it returns (in order)
2798: + 1 - the `KSP` used for the (1,1) block
2799: . 2 - the `KSP` used for the Schur complement (not the one used for the interior Schur solver)
2800: - 3 - the `KSP` used for the (1,1) block in the upper triangular factor (if different from that of the (1,1) block).
2802: It returns a null array if the fieldsplit is not of type `PC_COMPOSITE_SCHUR`; in this case, you should use `PCFieldSplitGetSubKSP()`.
2804: Fortran Note:
2805: Call `PCFieldSplitSchurRestoreSubKSP()` when the array of `KSP` is no longer needed
2807: Developer Notes:
2808: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2810: Should the functionality of `PCFieldSplitSchurGetSubKSP()` and `PCFieldSplitGetSubKSP()` be merged?
2812: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitGetSubKSP()`
2813: @*/
2814: PetscErrorCode PCFieldSplitSchurGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2815: {
2816: PetscFunctionBegin;
2818: if (n) PetscAssertPointer(n, 2);
2819: PetscUseMethod(pc, "PCFieldSplitSchurGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2820: PetscFunctionReturn(PETSC_SUCCESS);
2821: }
2823: /*@
2824: PCFieldSplitSetSchurPre - Indicates from what operator the preconditioner is constructed for the Schur complement.
2825: The default is the A11 matrix.
2827: Collective
2829: Input Parameters:
2830: + pc - the preconditioner context
2831: . ptype - which matrix to use for preconditioning the Schur complement: `PC_FIELDSPLIT_SCHUR_PRE_A11` (default),
2832: `PC_FIELDSPLIT_SCHUR_PRE_SELF`, `PC_FIELDSPLIT_SCHUR_PRE_USER`,
2833: `PC_FIELDSPLIT_SCHUR_PRE_SELFP`, and `PC_FIELDSPLIT_SCHUR_PRE_FULL`
2834: - pre - matrix to use for preconditioning, or `NULL`
2836: Options Database Keys:
2837: + -pc_fieldsplit_schur_precondition (self|selfp|user|a11|full) - default is `a11`. See notes for meaning of various arguments
2838: - -fieldsplit_1_pc_type pctype - the preconditioner algorithm that is used to construct the preconditioner from the operator
2840: Level: intermediate
2842: Notes:
2843: If ptype is
2844: + a11 - the preconditioner for the Schur complement is generated from the block diagonal part of the preconditioner
2845: matrix associated with the Schur complement (i.e. A11), not the Schur complement matrix
2846: . self - the preconditioner for the Schur complement is generated from the symbolic representation of the Schur complement matrix:
2847: The only preconditioners that currently work with this symbolic representation matrix object are `PCLSC` and `PCHPDDM`
2848: . user - the preconditioner for the Schur complement is generated from the user provided matrix (pre argument
2849: to this function).
2850: . selfp - the preconditioning for the Schur complement is generated from an explicitly-assembled approximation $ Sp = A11 - A10 inv(diag(A00)) A01 $
2851: This is only a good preconditioner when diag(A00) is a good preconditioner for A00. Optionally, A00 can be
2852: lumped before extracting the diagonal using the additional option `-fieldsplit_1_mat_schur_complement_ainv_type lump`
2853: - full - the preconditioner for the Schur complement is generated from the exact Schur complement matrix representation
2854: computed internally by `PCFIELDSPLIT` (this is expensive)
2855: useful mostly as a test that the Schur complement approach can work for your problem
2857: When solving a saddle point problem, where the A11 block is identically zero, using `a11` as the ptype only makes sense
2858: with the additional option `-fieldsplit_1_pc_type none`. Usually for saddle point problems one would use a `ptype` of `self` and
2859: `-fieldsplit_1_pc_type lsc` which uses the least squares commutator to compute a preconditioner for the Schur complement.
2861: Developer Note:
2862: The name of this function and the option `-pc_fieldsplit_schur_precondition` are inconsistent; precondition should be used everywhere.
2864: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`,
2865: `MatSchurComplementSetAinvType()`, `PCLSC`, `PCFieldSplitSetSchurFactType()`
2866: @*/
2867: PetscErrorCode PCFieldSplitSetSchurPre(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2868: {
2869: PetscFunctionBegin;
2871: PetscTryMethod(pc, "PCFieldSplitSetSchurPre_C", (PC, PCFieldSplitSchurPreType, Mat), (pc, ptype, pre));
2872: PetscFunctionReturn(PETSC_SUCCESS);
2873: }
2875: PetscErrorCode PCFieldSplitSchurPrecondition(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2876: {
2877: return PCFieldSplitSetSchurPre(pc, ptype, pre);
2878: } /* Deprecated name */
2880: /*@
2881: PCFieldSplitGetSchurPre - For Schur complement fieldsplit, determine how the Schur complement will be
2882: preconditioned. See `PCFieldSplitSetSchurPre()` for details.
2884: Logically Collective
2886: Input Parameter:
2887: . pc - the preconditioner context
2889: Output Parameters:
2890: + 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`
2891: - pre - matrix to use for preconditioning (with `PC_FIELDSPLIT_SCHUR_PRE_USER`), or `NULL`
2893: Level: intermediate
2895: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCLSC`
2896: @*/
2897: PetscErrorCode PCFieldSplitGetSchurPre(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2898: {
2899: PetscFunctionBegin;
2901: PetscUseMethod(pc, "PCFieldSplitGetSchurPre_C", (PC, PCFieldSplitSchurPreType *, Mat *), (pc, ptype, pre));
2902: PetscFunctionReturn(PETSC_SUCCESS);
2903: }
2905: /*@
2906: PCFieldSplitSchurGetS - extract the `MATSCHURCOMPLEMENT` object used by this `PCFIELDSPLIT` in case it needs to be configured separately
2908: Not Collective
2910: Input Parameter:
2911: . pc - the preconditioner context
2913: Output Parameter:
2914: . S - the Schur complement matrix
2916: Level: advanced
2918: Note:
2919: This matrix should not be destroyed using `MatDestroy()`; rather, use `PCFieldSplitSchurRestoreS()`.
2921: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MATSCHURCOMPLEMENT`, `PCFieldSplitSchurRestoreS()`,
2922: `MatCreateSchurComplement()`, `MatSchurComplementGetKSP()`, `MatSchurComplementComputeExplicitOperator()`, `MatGetSchurComplement()`
2923: @*/
2924: PetscErrorCode PCFieldSplitSchurGetS(PC pc, Mat *S)
2925: {
2926: const char *t;
2927: PetscBool isfs;
2928: PC_FieldSplit *jac;
2930: PetscFunctionBegin;
2932: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2933: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2934: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2935: jac = (PC_FieldSplit *)pc->data;
2936: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2937: if (S) *S = jac->schur;
2938: PetscFunctionReturn(PETSC_SUCCESS);
2939: }
2941: /*@
2942: PCFieldSplitSchurRestoreS - returns the `MATSCHURCOMPLEMENT` matrix used by this `PC`
2944: Not Collective
2946: Input Parameters:
2947: + pc - the preconditioner context
2948: - S - the Schur complement matrix
2950: Level: advanced
2952: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MatSchurComplement`, `PCFieldSplitSchurGetS()`
2953: @*/
2954: PetscErrorCode PCFieldSplitSchurRestoreS(PC pc, Mat *S)
2955: {
2956: const char *t;
2957: PetscBool isfs;
2958: PC_FieldSplit *jac;
2960: PetscFunctionBegin;
2962: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2963: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2964: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2965: jac = (PC_FieldSplit *)pc->data;
2966: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2967: PetscCheck(S && (*S == jac->schur), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MatSchurComplement restored is not the same as gotten");
2968: PetscFunctionReturn(PETSC_SUCCESS);
2969: }
2971: static PetscErrorCode PCFieldSplitSetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2972: {
2973: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2975: PetscFunctionBegin;
2976: jac->schurpre = ptype;
2977: if (ptype == PC_FIELDSPLIT_SCHUR_PRE_USER && pre) {
2978: PetscCall(MatDestroy(&jac->schur_user));
2979: jac->schur_user = pre;
2980: PetscCall(PetscObjectReference((PetscObject)jac->schur_user));
2981: }
2982: PetscFunctionReturn(PETSC_SUCCESS);
2983: }
2985: static PetscErrorCode PCFieldSplitGetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2986: {
2987: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2989: PetscFunctionBegin;
2990: if (ptype) *ptype = jac->schurpre;
2991: if (pre) *pre = jac->schur_user;
2992: PetscFunctionReturn(PETSC_SUCCESS);
2993: }
2995: /*@
2996: PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain in the preconditioner {cite}`murphy2000note` and {cite}`ipsen2001note`
2998: Collective
3000: Input Parameters:
3001: + pc - the preconditioner context
3002: - ftype - which blocks of factorization to retain, `PC_FIELDSPLIT_SCHUR_FACT_FULL` is default
3004: Options Database Key:
3005: . -pc_fieldsplit_schur_fact_type (diag|lower|upper|full) - default is `full`
3007: Level: intermediate
3009: Notes:
3010: The `full` factorization is
3012: ```{math}
3013: \left(\begin{array}{cc} A & B \\
3014: C & E \\
3015: \end{array}\right) =
3016: \left(\begin{array}{cc} I & 0 \\
3017: C A^{-1} & I \\
3018: \end{array}\right)
3019: \left(\begin{array}{cc} A & 0 \\
3020: 0 & S \\
3021: \end{array}\right)
3022: \left(\begin{array}{cc} I & A^{-1}B \\
3023: 0 & I \\
3024: \end{array}\right) = L D U,
3025: ```
3027: 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 $LD$,
3028: and `diag` is the diagonal part with the sign of $S$ flipped (because this makes the preconditioner positive definite for many formulations,
3029: thus allowing the use of `KSPMINRES)`. Sign flipping of $S$ can be turned off with `PCFieldSplitSetSchurScale()`.
3031: If $A$ and $S$ are solved exactly
3032: + 1 - `full` factorization is a direct solver.
3033: . 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.
3034: - 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.
3036: If the iteration count is very low, consider using `KSPFGMRES` or `KSPGCR` which can use one less preconditioner
3037: application in this case. Note that the preconditioned operator may be highly non-normal, so such fast convergence may not be observed in practice.
3039: For symmetric problems in which $A$ is positive definite and $S$ is negative definite, `diag` can be used with `KSPMINRES`.
3041: 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 $S$).
3043: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurScale()`,
3044: [](sec_flexibleksp), `PCFieldSplitSetSchurPre()`
3045: @*/
3046: PetscErrorCode PCFieldSplitSetSchurFactType(PC pc, PCFieldSplitSchurFactType ftype)
3047: {
3048: PetscFunctionBegin;
3050: PetscTryMethod(pc, "PCFieldSplitSetSchurFactType_C", (PC, PCFieldSplitSchurFactType), (pc, ftype));
3051: PetscFunctionReturn(PETSC_SUCCESS);
3052: }
3054: static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc, PCFieldSplitSchurFactType ftype)
3055: {
3056: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3058: PetscFunctionBegin;
3059: jac->schurfactorization = ftype;
3060: PetscFunctionReturn(PETSC_SUCCESS);
3061: }
3063: /*@
3064: PCFieldSplitSetSchurScale - Controls the sign flip of S for `PC_FIELDSPLIT_SCHUR_FACT_DIAG`.
3066: Collective
3068: Input Parameters:
3069: + pc - the preconditioner context
3070: - scale - scaling factor for the Schur complement
3072: Options Database Key:
3073: . -pc_fieldsplit_schur_scale scale - default is -1.0
3075: Level: intermediate
3077: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurFactType`, `PCFieldSplitSetSchurFactType()`
3078: @*/
3079: PetscErrorCode PCFieldSplitSetSchurScale(PC pc, PetscScalar scale)
3080: {
3081: PetscFunctionBegin;
3084: PetscTryMethod(pc, "PCFieldSplitSetSchurScale_C", (PC, PetscScalar), (pc, scale));
3085: PetscFunctionReturn(PETSC_SUCCESS);
3086: }
3088: static PetscErrorCode PCFieldSplitSetSchurScale_FieldSplit(PC pc, PetscScalar scale)
3089: {
3090: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3092: PetscFunctionBegin;
3093: jac->schurscale = scale;
3094: PetscFunctionReturn(PETSC_SUCCESS);
3095: }
3097: /*@C
3098: PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement
3100: Collective
3102: Input Parameter:
3103: . pc - the preconditioner context
3105: Output Parameters:
3106: + A00 - the (0,0) block
3107: . A01 - the (0,1) block
3108: . A10 - the (1,0) block
3109: - A11 - the (1,1) block
3111: Level: advanced
3113: Note:
3114: Use `NULL` for any unneeded output arguments
3116: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `MatSchurComplementGetSubMatrices()`, `MatSchurComplementSetSubMatrices()`
3117: @*/
3118: PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc, Mat *A00, Mat *A01, Mat *A10, Mat *A11)
3119: {
3120: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3122: PetscFunctionBegin;
3124: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach.");
3125: if (A00) *A00 = jac->pmat[0];
3126: if (A01) *A01 = jac->B;
3127: if (A10) *A10 = jac->C;
3128: if (A11) *A11 = jac->pmat[1];
3129: PetscFunctionReturn(PETSC_SUCCESS);
3130: }
3132: /*@
3133: PCFieldSplitSetGKBTol - Sets the solver tolerance for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
3135: Collective
3137: Input Parameters:
3138: + pc - the preconditioner context
3139: - tolerance - the solver tolerance
3141: Options Database Key:
3142: . -pc_fieldsplit_gkb_tol tolerance - default is 1e-5
3144: Level: intermediate
3146: Note:
3147: The generalized GKB algorithm {cite}`arioli2013` uses a lower bound estimate of the error in energy norm as stopping criterion.
3148: It stops once the lower bound estimate undershoots the required solver tolerance. Although the actual error might be bigger than
3149: this estimate, the stopping criterion is satisfactory in practical cases.
3151: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBMaxit()`
3152: @*/
3153: PetscErrorCode PCFieldSplitSetGKBTol(PC pc, PetscReal tolerance)
3154: {
3155: PetscFunctionBegin;
3158: PetscTryMethod(pc, "PCFieldSplitSetGKBTol_C", (PC, PetscReal), (pc, tolerance));
3159: PetscFunctionReturn(PETSC_SUCCESS);
3160: }
3162: static PetscErrorCode PCFieldSplitSetGKBTol_FieldSplit(PC pc, PetscReal tolerance)
3163: {
3164: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3166: PetscFunctionBegin;
3167: jac->gkbtol = tolerance;
3168: PetscFunctionReturn(PETSC_SUCCESS);
3169: }
3171: /*@
3172: PCFieldSplitSetGKBMaxit - Sets the maximum number of iterations for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
3174: Collective
3176: Input Parameters:
3177: + pc - the preconditioner context
3178: - maxit - the maximum number of iterations
3180: Options Database Key:
3181: . -pc_fieldsplit_gkb_maxit maxit - default is 100
3183: Level: intermediate
3185: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBNu()`
3186: @*/
3187: PetscErrorCode PCFieldSplitSetGKBMaxit(PC pc, PetscInt maxit)
3188: {
3189: PetscFunctionBegin;
3192: PetscTryMethod(pc, "PCFieldSplitSetGKBMaxit_C", (PC, PetscInt), (pc, maxit));
3193: PetscFunctionReturn(PETSC_SUCCESS);
3194: }
3196: static PetscErrorCode PCFieldSplitSetGKBMaxit_FieldSplit(PC pc, PetscInt maxit)
3197: {
3198: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3200: PetscFunctionBegin;
3201: jac->gkbmaxit = maxit;
3202: PetscFunctionReturn(PETSC_SUCCESS);
3203: }
3205: /*@
3206: PCFieldSplitSetGKBDelay - Sets the delay in the lower bound error estimate in the generalized Golub-Kahan bidiagonalization {cite}`arioli2013` in `PCFIELDSPLIT`
3207: preconditioner.
3209: Collective
3211: Input Parameters:
3212: + pc - the preconditioner context
3213: - delay - the delay window in the lower bound estimate
3215: Options Database Key:
3216: . -pc_fieldsplit_gkb_delay delay - default is 5
3218: Level: intermediate
3220: Notes:
3221: 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 $
3222: is expressed as a truncated sum. The error at iteration k can only be measured at iteration (k + `delay`), and thus the algorithm needs
3223: at least (`delay` + 1) iterations to stop.
3225: For more details on the generalized Golub-Kahan bidiagonalization method and its lower bound stopping criterion, please refer to {cite}`arioli2013`
3227: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
3228: @*/
3229: PetscErrorCode PCFieldSplitSetGKBDelay(PC pc, PetscInt delay)
3230: {
3231: PetscFunctionBegin;
3234: PetscTryMethod(pc, "PCFieldSplitSetGKBDelay_C", (PC, PetscInt), (pc, delay));
3235: PetscFunctionReturn(PETSC_SUCCESS);
3236: }
3238: static PetscErrorCode PCFieldSplitSetGKBDelay_FieldSplit(PC pc, PetscInt delay)
3239: {
3240: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3242: PetscFunctionBegin;
3243: jac->gkbdelay = delay;
3244: PetscFunctionReturn(PETSC_SUCCESS);
3245: }
3247: /*@
3248: PCFieldSplitSetGKBNu - Sets the scalar value nu >= 0 in the transformation H = A00 + nu*A01*A01' of the (1,1) block in the
3249: Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
3251: Collective
3253: Input Parameters:
3254: + pc - the preconditioner context
3255: - nu - the shift parameter
3257: Options Database Key:
3258: . -pc_fieldsplit_gkb_nu nu - default is 1
3260: Level: intermediate
3262: Notes:
3263: 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,
3264: 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
3265: necessary to find a good balance in between the convergence of the inner and outer loop.
3267: 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.
3269: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
3270: @*/
3271: PetscErrorCode PCFieldSplitSetGKBNu(PC pc, PetscReal nu)
3272: {
3273: PetscFunctionBegin;
3276: PetscTryMethod(pc, "PCFieldSplitSetGKBNu_C", (PC, PetscReal), (pc, nu));
3277: PetscFunctionReturn(PETSC_SUCCESS);
3278: }
3280: static PetscErrorCode PCFieldSplitSetGKBNu_FieldSplit(PC pc, PetscReal nu)
3281: {
3282: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3284: PetscFunctionBegin;
3285: jac->gkbnu = nu;
3286: PetscFunctionReturn(PETSC_SUCCESS);
3287: }
3289: static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc, PCCompositeType type)
3290: {
3291: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3293: PetscFunctionBegin;
3294: jac->type = type;
3295: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
3296: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
3297: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
3298: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
3299: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
3300: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
3301: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
3302: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
3303: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
3305: if (type == PC_COMPOSITE_SCHUR) {
3306: pc->ops->apply = PCApply_FieldSplit_Schur;
3307: pc->ops->applytranspose = PCApplyTranspose_FieldSplit_Schur;
3308: pc->ops->matapply = PCMatApply_FieldSplit_Schur;
3309: pc->ops->view = PCView_FieldSplit_Schur;
3310: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_Schur;
3312: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit_Schur));
3313: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", PCFieldSplitSetSchurPre_FieldSplit));
3314: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", PCFieldSplitGetSchurPre_FieldSplit));
3315: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", PCFieldSplitSetSchurFactType_FieldSplit));
3316: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", PCFieldSplitSetSchurScale_FieldSplit));
3317: } else if (type == PC_COMPOSITE_GKB) {
3318: pc->ops->apply = PCApply_FieldSplit_GKB;
3319: pc->ops->applytranspose = NULL;
3320: pc->ops->matapply = NULL;
3321: pc->ops->view = PCView_FieldSplit_GKB;
3322: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_GKB;
3324: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3325: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", PCFieldSplitSetGKBTol_FieldSplit));
3326: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", PCFieldSplitSetGKBMaxit_FieldSplit));
3327: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", PCFieldSplitSetGKBNu_FieldSplit));
3328: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", PCFieldSplitSetGKBDelay_FieldSplit));
3329: } else {
3330: pc->ops->apply = PCApply_FieldSplit;
3331: pc->ops->applytranspose = PCApplyTranspose_FieldSplit;
3332: pc->ops->matapply = PCMatApply_FieldSplit;
3333: pc->ops->view = PCView_FieldSplit;
3334: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit;
3336: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3337: }
3338: PetscFunctionReturn(PETSC_SUCCESS);
3339: }
3341: static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc, PetscInt bs)
3342: {
3343: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3345: PetscFunctionBegin;
3346: PetscCheck(bs >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Blocksize must be positive, you gave %" PetscInt_FMT, bs);
3347: 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);
3348: jac->bs = bs;
3349: PetscFunctionReturn(PETSC_SUCCESS);
3350: }
3352: static PetscErrorCode PCSetCoordinates_FieldSplit(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[])
3353: {
3354: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3355: PC_FieldSplitLink ilink_current = jac->head;
3356: IS is_owned;
3358: PetscFunctionBegin;
3359: jac->coordinates_set = PETSC_TRUE; // Internal flag
3360: PetscCall(MatGetOwnershipIS(pc->mat, &is_owned, NULL));
3362: while (ilink_current) {
3363: // For each IS, embed it to get local coords indces
3364: IS is_coords;
3365: PetscInt ndofs_block;
3366: const PetscInt *block_dofs_enumeration; // Numbering of the dofs relevant to the current block
3368: // Setting drop to true for safety. It should make no difference.
3369: PetscCall(ISEmbed(ilink_current->is, is_owned, PETSC_TRUE, &is_coords));
3370: PetscCall(ISGetLocalSize(is_coords, &ndofs_block));
3371: PetscCall(ISGetIndices(is_coords, &block_dofs_enumeration));
3373: // Allocate coordinates vector and set it directly
3374: PetscCall(PetscMalloc1(ndofs_block * dim, &ilink_current->coords));
3375: for (PetscInt dof = 0; dof < ndofs_block; ++dof) {
3376: for (PetscInt d = 0; d < dim; ++d) (ilink_current->coords)[dim * dof + d] = coords[dim * block_dofs_enumeration[dof] + d];
3377: }
3378: ilink_current->dim = dim;
3379: ilink_current->ndofs = ndofs_block;
3380: PetscCall(ISRestoreIndices(is_coords, &block_dofs_enumeration));
3381: PetscCall(ISDestroy(&is_coords));
3382: ilink_current = ilink_current->next;
3383: }
3384: PetscCall(ISDestroy(&is_owned));
3385: PetscFunctionReturn(PETSC_SUCCESS);
3386: }
3388: /*@
3389: PCFieldSplitSetType - Sets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3391: Collective
3393: Input Parameters:
3394: + pc - the preconditioner context
3395: - type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`,
3396: `PC_COMPOSITE_GKB`
3398: Options Database Key:
3399: . -pc_fieldsplit_type (multiplicative|additive|symmetric_multiplicative|special|schur) - Sets fieldsplit preconditioner type
3401: Level: intermediate
3403: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCCompositeType`, `PCCompositeGetType()`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3404: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`, `PCFieldSplitSetSchurFactType()`
3405: @*/
3406: PetscErrorCode PCFieldSplitSetType(PC pc, PCCompositeType type)
3407: {
3408: PetscFunctionBegin;
3410: PetscTryMethod(pc, "PCFieldSplitSetType_C", (PC, PCCompositeType), (pc, type));
3411: PetscFunctionReturn(PETSC_SUCCESS);
3412: }
3414: /*@
3415: PCFieldSplitGetType - Gets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3417: Not collective
3419: Input Parameter:
3420: . pc - the preconditioner context
3422: Output Parameter:
3423: . type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3425: Level: intermediate
3427: .seealso: [](sec_block_matrices), `PC`, `PCCompositeSetType()`, `PCFIELDSPLIT`, `PCCompositeType`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3428: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3429: @*/
3430: PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type)
3431: {
3432: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3434: PetscFunctionBegin;
3436: PetscAssertPointer(type, 2);
3437: *type = jac->type;
3438: PetscFunctionReturn(PETSC_SUCCESS);
3439: }
3441: /*@
3442: PCFieldSplitSetDMSplits - Flags whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3444: Logically Collective
3446: Input Parameters:
3447: + pc - the preconditioner context
3448: - flg - boolean indicating whether to use field splits defined by the `DM`
3450: Options Database Key:
3451: . -pc_fieldsplit_dm_splits (true|false) - use the field splits defined by the `DM`
3453: Level: intermediate
3455: Developer Note:
3456: The name should be `PCFieldSplitSetUseDMSplits()`, similar change to options database
3458: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3459: @*/
3460: PetscErrorCode PCFieldSplitSetDMSplits(PC pc, PetscBool flg)
3461: {
3462: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3463: PetscBool isfs;
3465: PetscFunctionBegin;
3468: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3469: if (isfs) jac->dm_splits = flg;
3470: PetscFunctionReturn(PETSC_SUCCESS);
3471: }
3473: /*@
3474: PCFieldSplitGetDMSplits - Returns flag indicating whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3476: Logically Collective
3478: Input Parameter:
3479: . pc - the preconditioner context
3481: Output Parameter:
3482: . flg - boolean indicating whether to use field splits defined by the `DM`
3484: Level: intermediate
3486: Developer Note:
3487: The name should be `PCFieldSplitGetUseDMSplits()`
3489: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3490: @*/
3491: PetscErrorCode PCFieldSplitGetDMSplits(PC pc, PetscBool *flg)
3492: {
3493: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3494: PetscBool isfs;
3496: PetscFunctionBegin;
3498: PetscAssertPointer(flg, 2);
3499: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3500: if (isfs) {
3501: if (flg) *flg = jac->dm_splits;
3502: }
3503: PetscFunctionReturn(PETSC_SUCCESS);
3504: }
3506: /*@
3507: PCFieldSplitGetDetectSaddlePoint - Returns flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3509: Logically Collective
3511: Input Parameter:
3512: . pc - the preconditioner context
3514: Output Parameter:
3515: . flg - boolean indicating whether to detect fields or not
3517: Level: intermediate
3519: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDetectSaddlePoint()`
3520: @*/
3521: PetscErrorCode PCFieldSplitGetDetectSaddlePoint(PC pc, PetscBool *flg)
3522: {
3523: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3525: PetscFunctionBegin;
3526: *flg = jac->detect;
3527: PetscFunctionReturn(PETSC_SUCCESS);
3528: }
3530: /*@
3531: PCFieldSplitSetDetectSaddlePoint - Sets flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3533: Logically Collective
3535: Input Parameter:
3536: . pc - the preconditioner context
3538: Output Parameter:
3539: . flg - boolean indicating whether to detect fields or not
3541: Options Database Key:
3542: . -pc_fieldsplit_detect_saddle_point (true|false) - detect and use the saddle point
3544: Level: intermediate
3546: Note:
3547: Also sets the split type to `PC_COMPOSITE_SCHUR` (see `PCFieldSplitSetType()`) and the Schur preconditioner type to `PC_FIELDSPLIT_SCHUR_PRE_SELF` (see `PCFieldSplitSetSchurPre()`).
3549: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDetectSaddlePoint()`, `PCFieldSplitSetType()`, `PCFieldSplitSetSchurPre()`, `PC_FIELDSPLIT_SCHUR_PRE_SELF`
3550: @*/
3551: PetscErrorCode PCFieldSplitSetDetectSaddlePoint(PC pc, PetscBool flg)
3552: {
3553: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3555: PetscFunctionBegin;
3556: jac->detect = flg;
3557: if (jac->detect) {
3558: PetscCall(PCFieldSplitSetType(pc, PC_COMPOSITE_SCHUR));
3559: PetscCall(PCFieldSplitSetSchurPre(pc, PC_FIELDSPLIT_SCHUR_PRE_SELF, NULL));
3560: }
3561: PetscFunctionReturn(PETSC_SUCCESS);
3562: }
3564: /*MC
3565: PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual
3566: collections of variables (that may overlap) called fields or splits. Each field often represents a different continuum variable
3567: represented on a grid, such as velocity, pressure, or temperature.
3568: In the literature these are sometimes called block preconditioners; but should not be confused with `PCBJACOBI`.
3569: See [the users manual section on "Solving Block Matrices"](sec_block_matrices) for more details.
3571: Options Database Keys:
3572: + -pc_fieldsplit_%d_fields a,b,... - indicates the fields to be used in the `%d`'th split
3573: . -pc_fieldsplit_default - automatically add any fields to additional splits that have not
3574: been supplied explicitly by `-pc_fieldsplit_%d_fields`
3575: . -pc_fieldsplit_block_size bs - size of block that defines fields (i.e. there are bs fields)
3576: when the matrix is not of `MatType` `MATNEST`
3577: . -pc_fieldsplit_type (additive|multiplicative|symmetric_multiplicative|schur|gkb) - type of relaxation or factorization splitting
3578: . -pc_fieldsplit_schur_precondition (self|selfp|user|a11|full) - default is `a11`; see `PCFieldSplitSetSchurPre()`
3579: . -pc_fieldsplit_schur_fact_type (diag|lower|upper|full) - set factorization type when using `-pc_fieldsplit_type schur`;
3580: see `PCFieldSplitSetSchurFactType()`
3581: . -pc_fieldsplit_dm_splits (true|false) (default is true) - Whether to use `DMCreateFieldDecomposition()` for splits
3582: - -pc_fieldsplit_detect_saddle_point (true|false) - automatically finds rows with zero diagonal and uses Schur complement with no preconditioner as the solver
3584: Options prefixes for inner solvers when using the Schur complement preconditioner are `-fieldsplit_0_` and `-fieldsplit_1_` .
3585: The options prefix for the inner solver when using the Golub-Kahan biadiagonalization preconditioner is `-fieldsplit_0_`
3586: For all other solvers they are `-fieldsplit_%d_` for the `%d`'th field; use `-fieldsplit_` for all fields.
3588: To set options on the solvers for all blocks, prepend `-fieldsplit_` to all the `PC`
3589: options database keys. For example, `-fieldsplit_pc_type ilu` `-fieldsplit_pc_factor_levels 1`.
3591: To set the options on the solvers separate for each block call `PCFieldSplitGetSubKSP()`
3592: and set the options directly on the resulting `KSP` object
3594: Level: intermediate
3596: Notes:
3597: Use `PCFieldSplitSetFields()` to set splits defined by "strided" entries or with a `MATNEST` and `PCFieldSplitSetIS()`
3598: to define a split by an arbitrary collection of entries.
3600: If no splits are set, the default is used. If a `DM` is associated with the `PC` and it supports
3601: `DMCreateFieldDecomposition()`, then that is used for the default. Otherwise if the matrix is not `MATNEST`, the splits are defined by entries strided by bs,
3602: beginning at 0 then 1, etc to bs-1. The block size can be set with `PCFieldSplitSetBlockSize()`,
3603: if this is not called the block size defaults to the blocksize of the second matrix passed
3604: to `KSPSetOperators()`/`PCSetOperators()`.
3606: For the Schur complement preconditioner if
3607: ```{math}
3608: J = \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{10} & A_{11} \end{array}\right]
3609: ```
3611: the preconditioner using `full` factorization is logically
3612: ```{math}
3613: \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]
3614: ```
3615: where the action of $\text{ksp}(A_{00})$ is applied using the `KSP` solver with prefix `-fieldsplit_0_`. $S$ is the Schur complement
3616: ```{math}
3617: S = A_{11} - A_{10} \text{ksp}(A_{00}) A_{01}
3618: ```
3619: 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`
3620: 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
3621: 0th index, the `KSP` associated with `-fieldsplit_0_`, and at its 1st index, the `KSP` corresponding to `-fieldsplit_1_`.
3622: By default, $A_{11}$ is used to construct a preconditioner for $S$, use `PCFieldSplitSetSchurPre()` for all the possible ways to construct the preconditioner for $S$.
3624: The factorization type is set using `-pc_fieldsplit_schur_fact_type <diag, lower, upper, full>`. `full` is shown above,
3625: `diag` gives
3626: ```{math}
3627: \left[\begin{array}{cc} \text{ksp}(A_{00}) & 0 \\ 0 & -\text{ksp}(S) \end{array}\right]
3628: ```
3629: 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
3630: can be turned off with `PCFieldSplitSetSchurScale()` or by command line `-pc_fieldsplit_schur_scale 1.0`. The `lower` factorization is the inverse of
3631: ```{math}
3632: \left[\begin{array}{cc} A_{00} & 0 \\ A_{10} & S \end{array}\right]
3633: ```
3634: where the inverses of $A_{00}$ and $S$ are applied using `KSP`s. The upper factorization is the inverse of
3635: ```{math}
3636: \left[\begin{array}{cc} A_{00} & A_{01} \\ 0 & S \end{array}\right]
3637: ```
3638: where again the inverses of $A_{00}$ and $S$ are applied using `KSP`s.
3640: If only one set of indices (one `IS`) is provided with `PCFieldSplitSetIS()` then the complement of that `IS`
3641: is used automatically for a second submatrix.
3643: The fieldsplit preconditioner cannot currently be used with the `MATBAIJ` or `MATSBAIJ` data formats if the blocksize is larger than 1.
3644: Generally it should be used with the `MATAIJ` or `MATNEST` `MatType`
3646: The forms of these preconditioners are closely related, if not identical, to forms derived as "Distributive Iterations", see,
3647: for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling {cite}`wesseling2009`.
3648: One can also use `PCFIELDSPLIT` inside a smoother resulting in "Distributive Smoothers".
3650: See "A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations" {cite}`elman2008tcp`.
3652: The Constrained Pressure Preconditioner (CPR) can be implemented using `PCCOMPOSITE` with `PCGALERKIN`. CPR first solves an $R A P$ subsystem, updates the
3653: residual on all variables (`PCCompositeSetType(pc,PC_COMPOSITE_MULTIPLICATIVE)`), and then applies a simple ILU like preconditioner on all the variables.
3655: The generalized Golub-Kahan bidiagonalization preconditioner (GKB) can be applied to symmetric $2 \times 2$ block matrices of the shape
3656: ```{math}
3657: \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{01}' & 0 \end{array}\right]
3658: ```
3659: 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 $H = _{A00} + \nu*A_{01}*A_{01}'$.
3660: 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_`.
3662: Some `PCFIELDSPLIT` variants are called physics-based preconditioners, since the preconditioner takes into account the underlying physics of the
3663: problem. But this nomenclature is not well-defined.
3665: Developer Note:
3666: The Schur complement functionality of `PCFIELDSPLIT` should likely be factored into its own `PC` thus simplifying the implementation of the preconditioners and their
3667: user API.
3669: .seealso: [](sec_block_matrices), `PC`, `PCCreate()`, `PCSetType()`, `PCType`, `PCLSC`,
3670: `PCFieldSplitGetSubKSP()`, `PCFieldSplitSchurGetSubKSP()`, `PCFieldSplitSetFields()`,
3671: `PCFieldSplitSetType()`, `PCFieldSplitSetIS()`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitSetSchurFactType()`,
3672: `MatSchurComplementSetAinvType()`, `PCFieldSplitSetSchurScale()`, `PCFieldSplitSetDetectSaddlePoint()`
3673: M*/
3675: PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc)
3676: {
3677: PC_FieldSplit *jac;
3679: PetscFunctionBegin;
3680: PetscCall(PetscNew(&jac));
3682: jac->bs = -1;
3683: jac->type = PC_COMPOSITE_MULTIPLICATIVE;
3684: jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */
3685: jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL;
3686: jac->schurscale = -1.0;
3687: jac->dm_splits = PETSC_TRUE;
3688: jac->gkbtol = 1e-5;
3689: jac->gkbdelay = 5;
3690: jac->gkbnu = 1;
3691: jac->gkbmaxit = 100;
3693: pc->data = (void *)jac;
3695: pc->ops->setup = PCSetUp_FieldSplit;
3696: pc->ops->reset = PCReset_FieldSplit;
3697: pc->ops->destroy = PCDestroy_FieldSplit;
3698: pc->ops->setfromoptions = PCSetFromOptions_FieldSplit;
3699: pc->ops->applyrichardson = NULL;
3701: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", PCFieldSplitSchurGetSubKSP_FieldSplit));
3702: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", PCFieldSplitSetFields_FieldSplit));
3703: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", PCFieldSplitSetIS_FieldSplit));
3704: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", PCFieldSplitSetType_FieldSplit));
3705: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", PCFieldSplitSetBlockSize_FieldSplit));
3706: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", PCFieldSplitRestrictIS_FieldSplit));
3707: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", PCSetCoordinates_FieldSplit));
3709: /* Initialize function pointers */
3710: PetscCall(PCFieldSplitSetType(pc, jac->type));
3711: PetscFunctionReturn(PETSC_SUCCESS);
3712: }