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: PetscCall(VecCreateMPIWithArrayAndMemType(PetscObjectComm((PetscObject)jac->schur), mtype, 1, m, M, array + m * P, &c));
1283: PetscCall(MatDenseRestoreArrayAndMemType(AinvB, &array));
1284: PetscCall(VecCopy(ilinkA->x, c));
1285: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1286: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, jac->schur_user));
1287: PetscCall(VecCopy(c, ilinkA->y)); // retrieve the solution as the last column of the composed Mat
1288: PetscCall(VecDestroy(&c));
1289: }
1290: }
1291: }
1292: if (N == P) PetscCall(KSPSolve(kspLower, ilinkA->x, ilinkA->y));
1293: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->y));
1294: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->y, NULL));
1295: PetscCall(MatMult(jac->C, ilinkA->y, ilinkD->x));
1296: PetscCall(VecScale(ilinkD->x, -1.0));
1297: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1298: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1300: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1301: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1302: PetscCall(KSPSolve(jac->kspschur, ilinkD->x, ilinkD->y));
1303: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1304: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1305: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1306: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1308: if (kspUpper == kspA) {
1309: if (!AinvB) {
1310: PetscCall(MatMult(jac->B, ilinkD->y, ilinkA->y));
1311: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1312: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1313: PetscCall(KSPSolve(kspA, ilinkA->x, ilinkA->y));
1314: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1315: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1316: } else PetscCall(MatMultAdd(AinvB, ilinkD->y, ilinkA->y, ilinkA->y));
1317: } else {
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(MatMult(jac->B, ilinkD->y, ilinkA->x));
1322: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1323: PetscCall(KSPSolve(kspUpper, ilinkA->x, ilinkA->z));
1324: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->z));
1325: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->z, NULL));
1326: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1327: }
1328: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1329: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1330: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1331: }
1332: PetscFunctionReturn(PETSC_SUCCESS);
1333: }
1335: /*
1336: PCFieldSplitCreateWorkMats_Private - Allocate per-field dense work matrices for multi-RHS
1338: Input Parameters:
1339: + pc - the PC context
1340: - X - matrix to copy column-layout from
1342: Notes:
1343: If matrices already exist with correct column count, they are reused.
1344: If column count changed, old matrices are destroyed and new ones created.
1345: */
1346: static PetscErrorCode PCFieldSplitCreateWorkMats_Private(PC pc, Mat X)
1347: {
1348: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1349: PC_FieldSplitLink ilink = jac->head;
1350: PetscInt mx, Mx, my, My, N;
1352: PetscFunctionBegin;
1353: while (ilink) {
1354: /* check if reallocation needed (previous allocation with wrong column count) */
1355: if (ilink->X) {
1356: PetscCall(MatGetSize(ilink->X, NULL, &N));
1357: if (N != X->cmap->N) {
1358: PetscCall(MatDestroy(&ilink->X));
1359: PetscCall(MatDestroy(&ilink->Y));
1360: PetscCall(MatDestroy(&ilink->Z));
1361: }
1362: }
1363: /* create if needed */
1364: if (!ilink->X) {
1365: VecType xtype, ytype;
1367: PetscCall(VecGetType(ilink->x, &xtype));
1368: PetscCall(VecGetType(ilink->y, &ytype));
1369: PetscCall(VecGetLocalSize(ilink->x, &mx));
1370: PetscCall(VecGetSize(ilink->x, &Mx));
1371: PetscCall(VecGetLocalSize(ilink->y, &my));
1372: PetscCall(VecGetSize(ilink->y, &My));
1373: /* use default lda */
1374: PetscCall(MatCreateDenseFromVecType(PetscObjectComm((PetscObject)pc), xtype, mx, X->cmap->n, Mx, X->cmap->N, PETSC_DECIDE, NULL, &ilink->X));
1375: PetscCall(MatCreateDenseFromVecType(PetscObjectComm((PetscObject)pc), ytype, my, X->cmap->n, My, X->cmap->N, PETSC_DECIDE, NULL, &ilink->Y));
1376: }
1377: ilink = ilink->next;
1378: }
1379: PetscFunctionReturn(PETSC_SUCCESS);
1380: }
1382: static PetscErrorCode PCMatApply_FieldSplit_Schur(PC pc, Mat X, Mat Y)
1383: {
1384: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1385: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1386: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1387: Mat AinvB = NULL;
1388: PetscInt N, P;
1390: PetscFunctionBegin;
1391: /* create working matrices with the correct number of columns */
1392: PetscCall(PCFieldSplitCreateWorkMats_Private(pc, X));
1393: switch (jac->schurfactorization) {
1394: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1395: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1396: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, INSERT_VALUES, SCATTER_FORWARD));
1397: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, INSERT_VALUES, SCATTER_FORWARD));
1398: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1399: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1400: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1401: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1402: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1403: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1404: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1405: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1406: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1407: PetscCall(MatScale(ilinkD->Y, jac->schurscale));
1408: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1409: break;
1410: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1411: /* [A00 0; A10 S], suitable for left preconditioning */
1412: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, INSERT_VALUES, SCATTER_FORWARD));
1413: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1414: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1415: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1416: PetscCall(MatMatMult(jac->C, ilinkA->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkD->X));
1417: PetscCall(MatScale(ilinkD->X, -1.0));
1418: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, ADD_VALUES, SCATTER_FORWARD));
1419: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1420: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1421: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1422: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1423: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1424: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1425: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1426: break;
1427: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1428: /* [A00 A01; 0 S], suitable for right preconditioning */
1429: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, INSERT_VALUES, SCATTER_FORWARD));
1430: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1431: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1432: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1433: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1434: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1435: PetscCall(MatMatMult(jac->B, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->X));
1436: PetscCall(MatScale(ilinkA->X, -1.0));
1437: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, ADD_VALUES, SCATTER_FORWARD));
1438: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1439: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1440: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1441: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1442: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1443: break;
1444: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1445: /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1] */
1446: PetscCall(MatGetSize(jac->B, NULL, &P));
1447: N = P;
1448: PetscCall(MatDenseScatter_Private(ilinkA->sctx, X, ilinkA->X, INSERT_VALUES, SCATTER_FORWARD));
1449: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->X, ilinkA->Y, NULL));
1450: if (kspUpper == kspA) {
1451: PetscCall(PetscObjectQuery((PetscObject)jac->schur, "AinvB", (PetscObject *)&AinvB));
1452: if (AinvB) {
1453: PetscCall(MatGetSize(AinvB, NULL, &N));
1454: if (N > P) { // first time PCApply_FieldSplit_Schur() is called
1455: PetscMemType mtype;
1456: Mat C = NULL;
1457: PetscScalar *array;
1458: PetscInt m, M, q, Q, p;
1460: PetscCall(MatGetSize(jac->B, &M, NULL));
1461: PetscCall(MatGetLocalSize(jac->B, &m, NULL));
1462: PetscCall(MatGetSize(X, NULL, &Q));
1463: PetscCall(MatGetLocalSize(X, NULL, &q));
1464: PetscCall(MatDenseGetArrayAndMemType(AinvB, &array, &mtype));
1465: if (N != P + Q) {
1466: Mat replace;
1468: PetscCall(MatGetLocalSize(jac->B, NULL, &p));
1469: if (PetscMemTypeCUDA(mtype)) {
1470: #if PetscDefined(HAVE_CUDA)
1471: PetscCallCUDA(cudaFree(array));
1472: PetscCallCUDA(cudaMalloc((void **)&array, sizeof(PetscScalar) * m * (P + Q)));
1473: #endif
1474: } else if (PetscMemTypeHIP(mtype)) {
1475: #if PetscDefined(HAVE_HIP)
1476: PetscCallHIP(hipFree(array));
1477: PetscCallHIP(hipMalloc((void **)&array, sizeof(PetscScalar) * m * (P + Q)));
1478: #endif
1479: } else {
1480: PetscCheck(PetscMemTypeHost(mtype), PetscObjectComm((PetscObject)jac->schur), PETSC_ERR_SUP, "PetscMemType should be either PETSC_MEMTYPE_HOST, PETSC_MEMTYPE_CUDA, or PETSC_MEMTYPE_HIP");
1481: PetscCall(PetscFree(array));
1482: PetscCall(PetscMalloc1(m * (P + Q), &array));
1483: }
1484: PetscCall(MatCreateDenseWithMemType(PetscObjectComm((PetscObject)jac->schur), mtype, m, PETSC_DECIDE, M, P + Q, PETSC_DECIDE, array, &replace));
1485: PetscCall(MatHeaderReplace(AinvB, &replace));
1486: }
1487: PetscCall(MatCreateDenseWithMemType(PetscObjectComm((PetscObject)jac->schur), mtype, m, q, M, Q, PETSC_DECIDE, array + m * P, &C));
1488: PetscCall(MatDenseRestoreArrayAndMemType(AinvB, &array));
1489: PetscCall(MatCopy(ilinkA->X, C, SAME_NONZERO_PATTERN));
1490: PetscCall(MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user));
1491: PetscCall(KSPSetOperators(jac->kspschur, jac->schur, jac->schur_user));
1492: PetscCall(MatCopy(C, ilinkA->Y, SAME_NONZERO_PATTERN)); // retrieve solutions as last columns of the composed Mat
1493: PetscCall(MatDestroy(&C));
1494: }
1495: }
1496: }
1497: if (N == P) PetscCall(KSPMatSolve(kspLower, ilinkA->X, ilinkA->Y));
1498: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->X, ilinkA->Y, NULL));
1499: PetscCall(MatMatMult(jac->C, ilinkA->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkD->X));
1500: PetscCall(MatScale(ilinkD->X, -1.0));
1501: PetscCall(MatDenseScatter_Private(ilinkD->sctx, X, ilinkD->X, ADD_VALUES, SCATTER_FORWARD));
1503: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1504: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1505: PetscCall(KSPMatSolve(jac->kspschur, ilinkD->X, ilinkD->Y));
1506: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1507: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->X, ilinkD->Y, NULL));
1508: PetscCall(MatDenseScatter_Private(ilinkD->sctx, ilinkD->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1510: if (kspUpper == kspA) {
1511: if (!AinvB) {
1512: PetscCall(MatMatMult(jac->B, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->Y));
1513: PetscCall(MatAXPY(ilinkA->X, -1.0, ilinkA->Y, SAME_NONZERO_PATTERN));
1514: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1515: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1516: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1517: } else {
1518: PetscCall(MatMatMult(AinvB, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->X));
1519: PetscCall(MatAXPY(ilinkA->Y, 1.0, ilinkA->X, SAME_NONZERO_PATTERN));
1520: }
1521: } else {
1522: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->X, ilinkA->Y, NULL));
1523: PetscCall(KSPMatSolve(kspA, ilinkA->X, ilinkA->Y));
1524: PetscCall(MatMatMult(jac->B, ilinkD->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilinkA->X));
1525: if (!ilinkA->Z) PetscCall(MatDuplicate(ilinkA->X, MAT_DO_NOT_COPY_VALUES, &ilinkA->Z));
1526: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->X, ilinkA->Z, NULL));
1527: PetscCall(KSPMatSolve(kspUpper, ilinkA->X, ilinkA->Z));
1528: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->X, ilinkA->Z, NULL));
1529: PetscCall(MatAXPY(ilinkA->Y, -1.0, ilinkA->Z, SAME_NONZERO_PATTERN));
1530: }
1531: PetscCall(MatDenseScatter_Private(ilinkA->sctx, ilinkA->Y, Y, INSERT_VALUES, SCATTER_REVERSE));
1532: }
1533: PetscFunctionReturn(PETSC_SUCCESS);
1534: }
1536: static PetscErrorCode PCApplyTranspose_FieldSplit_Schur(PC pc, Vec x, Vec y)
1537: {
1538: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1539: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1540: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
1542: PetscFunctionBegin;
1543: switch (jac->schurfactorization) {
1544: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
1545: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
1546: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1547: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1548: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1549: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1550: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1551: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1552: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1553: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1554: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1555: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1556: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1557: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1558: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1559: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1560: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1561: PetscCall(VecScale(ilinkD->y, jac->schurscale));
1562: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1563: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1564: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1565: break;
1566: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
1567: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1568: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1569: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1570: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1571: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1572: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1573: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1574: PetscCall(VecScale(ilinkD->x, -1.));
1575: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1576: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1577: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1578: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1579: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1580: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1581: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1582: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1583: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1584: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1585: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1586: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1587: break;
1588: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
1589: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1590: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1591: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1592: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1593: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1594: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1595: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1596: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1597: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1598: PetscCall(VecScale(ilinkA->x, -1.));
1599: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1600: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1601: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, ADD_VALUES, SCATTER_FORWARD));
1602: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1603: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1604: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1605: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1606: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1607: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1608: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1609: break;
1610: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
1611: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1612: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1613: PetscCall(PetscLogEventBegin(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1614: PetscCall(KSPSolveTranspose(kspUpper, ilinkA->x, ilinkA->y));
1615: PetscCall(KSPCheckSolve(kspUpper, pc, ilinkA->y));
1616: PetscCall(PetscLogEventEnd(KSP_Solve_FS_U, kspUpper, ilinkA->x, ilinkA->y, NULL));
1617: PetscCall(MatMultTranspose(jac->B, ilinkA->y, ilinkD->x));
1618: PetscCall(VecScale(ilinkD->x, -1.0));
1619: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1620: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, ADD_VALUES, SCATTER_FORWARD));
1622: PetscCall(PetscLogEventBegin(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1623: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, 1));
1624: PetscCall(KSPSolveTranspose(jac->kspschur, ilinkD->x, ilinkD->y));
1625: PetscCall(PetscObjectIncrementTabLevel((PetscObject)kspA, (PetscObject)kspA, -1));
1626: PetscCall(KSPCheckSolve(jac->kspschur, pc, ilinkD->y));
1627: PetscCall(PetscLogEventEnd(KSP_Solve_FS_S, jac->kspschur, ilinkD->x, ilinkD->y, NULL));
1628: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1630: if (kspLower == kspA) {
1631: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->y));
1632: PetscCall(VecAXPY(ilinkA->x, -1.0, ilinkA->y));
1633: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1634: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1635: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1636: PetscCall(PetscLogEventEnd(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1637: } else {
1638: PetscCall(PetscLogEventBegin(ilinkA->event, kspA, ilinkA->x, ilinkA->y, NULL));
1639: PetscCall(KSPSolveTranspose(kspA, ilinkA->x, ilinkA->y));
1640: PetscCall(KSPCheckSolve(kspA, pc, ilinkA->y));
1641: PetscCall(MatMultTranspose(jac->C, ilinkD->y, ilinkA->x));
1642: PetscCall(PetscLogEventBegin(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1643: PetscCall(KSPSolveTranspose(kspLower, ilinkA->x, ilinkA->z));
1644: PetscCall(KSPCheckSolve(kspLower, pc, ilinkA->z));
1645: PetscCall(PetscLogEventEnd(KSP_Solve_FS_L, kspLower, ilinkA->x, ilinkA->z, NULL));
1646: PetscCall(VecAXPY(ilinkA->y, -1.0, ilinkA->z));
1647: }
1648: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1649: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1650: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1651: }
1652: PetscFunctionReturn(PETSC_SUCCESS);
1653: }
1655: #define FieldSplitSplitSolveAdd(ilink, xx, yy) \
1656: ((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) || \
1657: 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) || \
1658: VecScatterEnd(ilink->sctx, ilink->y, yy, ADD_VALUES, SCATTER_REVERSE)))
1660: static PetscErrorCode PCApply_FieldSplit(PC pc, Vec x, Vec y)
1661: {
1662: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1663: PC_FieldSplitLink ilink = jac->head;
1664: PetscInt cnt, bs;
1666: PetscFunctionBegin;
1667: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1668: PetscBool matnest;
1670: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1671: if (jac->defaultsplit && !matnest) {
1672: PetscCall(VecGetBlockSize(x, &bs));
1673: 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);
1674: PetscCall(VecGetBlockSize(y, &bs));
1675: 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);
1676: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1677: while (ilink) {
1678: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1679: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1680: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1681: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1682: ilink = ilink->next;
1683: }
1684: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1685: } else {
1686: PetscCall(VecSet(y, 0.0));
1687: while (ilink) {
1688: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1689: ilink = ilink->next;
1690: }
1691: }
1692: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) {
1693: PetscCall(VecSet(y, 0.0));
1694: /* solve on first block for first block variables */
1695: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1696: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, INSERT_VALUES, SCATTER_FORWARD));
1697: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1698: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1699: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1700: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1701: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1702: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1704: /* compute the residual only onto second block variables using first block variables */
1705: PetscCall(MatMult(jac->Afield[1], ilink->y, ilink->next->x));
1706: ilink = ilink->next;
1707: PetscCall(VecScale(ilink->x, -1.0));
1708: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1709: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1711: /* solve on second block variables */
1712: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1713: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1714: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1715: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1716: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1717: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1718: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1719: if (!jac->w1) {
1720: PetscCall(VecDuplicate(x, &jac->w1));
1721: PetscCall(VecDuplicate(x, &jac->w2));
1722: }
1723: PetscCall(VecSet(y, 0.0));
1724: PetscCall(FieldSplitSplitSolveAdd(ilink, x, y));
1725: cnt = 1;
1726: while (ilink->next) {
1727: ilink = ilink->next;
1728: /* compute the residual only over the part of the vector needed */
1729: PetscCall(MatMult(jac->Afield[cnt++], y, ilink->x));
1730: PetscCall(VecScale(ilink->x, -1.0));
1731: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1732: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1733: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1734: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1735: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1736: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1737: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1738: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1739: }
1740: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1741: cnt -= 2;
1742: while (ilink->previous) {
1743: ilink = ilink->previous;
1744: /* compute the residual only over the part of the vector needed */
1745: PetscCall(MatMult(jac->Afield[cnt--], y, ilink->x));
1746: PetscCall(VecScale(ilink->x, -1.0));
1747: PetscCall(VecScatterBegin(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1748: PetscCall(VecScatterEnd(ilink->sctx, x, ilink->x, ADD_VALUES, SCATTER_FORWARD));
1749: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1750: PetscCall(KSPSolve(ilink->ksp, ilink->x, ilink->y));
1751: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1752: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1753: PetscCall(VecScatterBegin(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1754: PetscCall(VecScatterEnd(ilink->sctx, ilink->y, y, ADD_VALUES, SCATTER_REVERSE));
1755: }
1756: }
1757: } else SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Unsupported or unknown composition %d", (int)jac->type);
1758: PetscFunctionReturn(PETSC_SUCCESS);
1759: }
1761: static PetscErrorCode PCMatApply_FieldSplit(PC pc, Mat X, Mat Y)
1762: {
1763: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1764: PC_FieldSplitLink ilink = jac->head;
1765: PetscInt cnt;
1767: PetscFunctionBegin;
1768: /* create working matrices with the correct number of columns */
1769: PetscCall(PCFieldSplitCreateWorkMats_Private(pc, X));
1770: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1771: PetscCall(MatZeroEntries(Y));
1772: while (ilink) {
1773: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, INSERT_VALUES, SCATTER_FORWARD));
1774: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1775: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1776: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1777: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1778: ilink = ilink->next;
1779: }
1780: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) {
1781: PetscCall(MatZeroEntries(Y));
1782: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, INSERT_VALUES, SCATTER_FORWARD));
1783: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1784: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1785: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1786: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1788: /* compute the residual only onto second block variables using first block variables */
1789: PetscCall(MatMatMult(jac->Afield[1], ilink->Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilink->next->X));
1790: ilink = ilink->next;
1791: PetscCall(MatScale(ilink->X, -1.0));
1792: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, ADD_VALUES, SCATTER_FORWARD));
1794: /* solve on second block variables */
1795: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1796: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1797: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1798: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1799: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1800: /* general multiplicative with any number of splits */
1801: PetscCall(MatZeroEntries(Y));
1802: /* first split */
1803: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, INSERT_VALUES, SCATTER_FORWARD));
1804: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1805: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1806: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1807: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1808: cnt = 1;
1809: /* forward sweep */
1810: while (ilink->next) {
1811: ilink = ilink->next;
1812: /* compute the residual only over the part of the vector needed */
1813: PetscCall(MatMatMult(jac->Afield[cnt++], Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilink->X));
1814: PetscCall(MatScale(ilink->X, -1.0));
1815: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, ADD_VALUES, SCATTER_FORWARD));
1816: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1817: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1818: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1819: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1820: }
1821: /* backward sweep for symmetric multiplicative */
1822: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1823: cnt -= 2;
1824: while (ilink->previous) {
1825: ilink = ilink->previous;
1826: /* compute the residual only over the part of the vector needed */
1827: PetscCall(MatMatMult(jac->Afield[cnt--], Y, MAT_REUSE_MATRIX, PETSC_DETERMINE, &ilink->X));
1828: PetscCall(MatScale(ilink->X, -1.0));
1829: PetscCall(MatDenseScatter_Private(ilink->sctx, X, ilink->X, ADD_VALUES, SCATTER_FORWARD));
1830: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1831: PetscCall(KSPMatSolve(ilink->ksp, ilink->X, ilink->Y));
1832: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->X, ilink->Y, NULL));
1833: PetscCall(MatDenseScatter_Private(ilink->sctx, ilink->Y, Y, ADD_VALUES, SCATTER_REVERSE));
1834: }
1835: }
1836: } else SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "PCMatApply() not implemented for this fieldsplit type");
1837: PetscFunctionReturn(PETSC_SUCCESS);
1838: }
1840: static PetscErrorCode PCApply_FieldSplit_GKB(PC pc, Vec x, Vec y)
1841: {
1842: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1843: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
1844: KSP ksp = ilinkA->ksp;
1845: Vec u, v, Hu, d, work1, work2;
1846: PetscScalar alpha, z, nrmz2, *vecz;
1847: PetscReal lowbnd, nu, beta;
1848: PetscInt iterGKB;
1850: PetscFunctionBegin;
1851: PetscCall(VecScatterBegin(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1852: PetscCall(VecScatterBegin(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1853: PetscCall(VecScatterEnd(ilinkA->sctx, x, ilinkA->x, INSERT_VALUES, SCATTER_FORWARD));
1854: PetscCall(VecScatterEnd(ilinkD->sctx, x, ilinkD->x, INSERT_VALUES, SCATTER_FORWARD));
1856: u = jac->u;
1857: v = jac->v;
1858: Hu = jac->Hu;
1859: d = jac->d;
1860: work1 = jac->w1;
1861: work2 = jac->w2;
1862: vecz = jac->vecz;
1864: /* Change RHS to comply with matrix regularization H = A + nu*B*B' */
1865: /* Add q = q + nu*B*b */
1866: if (jac->gkbnu) {
1867: nu = jac->gkbnu;
1868: PetscCall(VecScale(ilinkD->x, jac->gkbnu));
1869: PetscCall(MatMultAdd(jac->B, ilinkD->x, ilinkA->x, ilinkA->x)); /* q = q + nu*B*b */
1870: } else {
1871: /* Situation when no augmented Lagrangian is used. Then we set inner */
1872: /* matrix N = I in [Ar13], and thus nu = 1. */
1873: nu = 1;
1874: }
1876: /* Transform rhs from [q,tilde{b}] to [0,b] */
1877: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1878: PetscCall(KSPSolve(ksp, ilinkA->x, ilinkA->y));
1879: PetscCall(KSPCheckSolve(ksp, pc, ilinkA->y));
1880: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, ilinkA->x, ilinkA->y, NULL));
1881: PetscCall(MatMultHermitianTranspose(jac->B, ilinkA->y, work1));
1882: PetscCall(VecAXPBY(work1, 1.0 / nu, -1.0, ilinkD->x)); /* c = b - B'*x */
1884: /* First step of algorithm */
1885: PetscCall(VecNorm(work1, NORM_2, &beta)); /* beta = sqrt(nu*c'*c)*/
1886: KSPCheckDot(ksp, beta);
1887: beta = PetscSqrtReal(nu) * beta;
1888: PetscCall(VecAXPBY(v, nu / beta, 0.0, work1)); /* v = nu/beta *c */
1889: PetscCall(MatMult(jac->B, v, work2)); /* u = H^{-1}*B*v */
1890: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1891: PetscCall(KSPSolve(ksp, work2, u));
1892: PetscCall(KSPCheckSolve(ksp, pc, u));
1893: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1894: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1895: PetscCall(VecDot(Hu, u, &alpha));
1896: KSPCheckDot(ksp, alpha);
1897: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1898: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1899: PetscCall(VecScale(u, 1.0 / alpha));
1900: PetscCall(VecAXPBY(d, 1.0 / alpha, 0.0, v)); /* v = nu/beta *c */
1902: z = beta / alpha;
1903: vecz[1] = z;
1905: /* Computation of first iterate x(1) and p(1) */
1906: PetscCall(VecAXPY(ilinkA->y, z, u));
1907: PetscCall(VecCopy(d, ilinkD->y));
1908: PetscCall(VecScale(ilinkD->y, -z));
1910: iterGKB = 1;
1911: lowbnd = 2 * jac->gkbtol;
1912: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1914: while (iterGKB < jac->gkbmaxit && lowbnd > jac->gkbtol) {
1915: iterGKB += 1;
1916: PetscCall(MatMultHermitianTranspose(jac->B, u, work1)); /* v <- nu*(B'*u-alpha/nu*v) */
1917: PetscCall(VecAXPBY(v, nu, -alpha, work1));
1918: PetscCall(VecNorm(v, NORM_2, &beta)); /* beta = sqrt(nu)*v'*v */
1919: beta = beta / PetscSqrtReal(nu);
1920: PetscCall(VecScale(v, 1.0 / beta));
1921: PetscCall(MatMult(jac->B, v, work2)); /* u <- H^{-1}*(B*v-beta*H*u) */
1922: PetscCall(MatMult(jac->H, u, Hu));
1923: PetscCall(VecAXPY(work2, -beta, Hu));
1924: PetscCall(PetscLogEventBegin(ilinkA->event, ksp, work2, u, NULL));
1925: PetscCall(KSPSolve(ksp, work2, u));
1926: PetscCall(KSPCheckSolve(ksp, pc, u));
1927: PetscCall(PetscLogEventEnd(ilinkA->event, ksp, work2, u, NULL));
1928: PetscCall(MatMult(jac->H, u, Hu)); /* alpha = u'*H*u */
1929: PetscCall(VecDot(Hu, u, &alpha));
1930: KSPCheckDot(ksp, alpha);
1931: PetscCheck(PetscRealPart(alpha) > 0.0, PETSC_COMM_SELF, PETSC_ERR_NOT_CONVERGED, "GKB preconditioner diverged, H is not positive definite");
1932: alpha = PetscSqrtReal(PetscAbsScalar(alpha));
1933: PetscCall(VecScale(u, 1.0 / alpha));
1935: z = -beta / alpha * z; /* z <- beta/alpha*z */
1936: vecz[0] = z;
1938: /* Computation of new iterate x(i+1) and p(i+1) */
1939: PetscCall(VecAXPBY(d, 1.0 / alpha, -beta / alpha, v)); /* d = (v-beta*d)/alpha */
1940: PetscCall(VecAXPY(ilinkA->y, z, u)); /* r = r + z*u */
1941: PetscCall(VecAXPY(ilinkD->y, -z, d)); /* p = p - z*d */
1942: PetscCall(MatMult(jac->H, ilinkA->y, Hu)); /* ||u||_H = u'*H*u */
1943: PetscCall(VecDot(Hu, ilinkA->y, &nrmz2));
1945: /* Compute Lower Bound estimate */
1946: if (iterGKB > jac->gkbdelay) {
1947: lowbnd = 0.0;
1948: for (PetscInt j = 0; j < jac->gkbdelay; j++) lowbnd += PetscAbsScalar(vecz[j] * vecz[j]);
1949: lowbnd = PetscSqrtReal(lowbnd / PetscAbsScalar(nrmz2));
1950: }
1952: for (PetscInt j = 0; j < jac->gkbdelay - 1; j++) vecz[jac->gkbdelay - j - 1] = vecz[jac->gkbdelay - j - 2];
1953: if (jac->gkbmonitor) PetscCall(PetscViewerASCIIPrintf(jac->gkbviewer, "%3" PetscInt_FMT " GKB Lower bound estimate %14.12e\n", iterGKB, (double)lowbnd));
1954: }
1956: PetscCall(VecScatterBegin(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1957: PetscCall(VecScatterEnd(ilinkA->sctx, ilinkA->y, y, INSERT_VALUES, SCATTER_REVERSE));
1958: PetscCall(VecScatterBegin(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1959: PetscCall(VecScatterEnd(ilinkD->sctx, ilinkD->y, y, INSERT_VALUES, SCATTER_REVERSE));
1960: PetscFunctionReturn(PETSC_SUCCESS);
1961: }
1963: #define FieldSplitSplitSolveAddTranspose(ilink, xx, yy) \
1964: ((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) || \
1965: 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) || \
1966: VecScatterEnd(ilink->sctx, ilink->x, yy, ADD_VALUES, SCATTER_REVERSE)))
1968: static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc, Vec x, Vec y)
1969: {
1970: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
1971: PC_FieldSplitLink ilink = jac->head;
1972: PetscInt bs;
1974: PetscFunctionBegin;
1975: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1976: PetscBool matnest;
1978: PetscCall(PetscObjectTypeCompare((PetscObject)pc->pmat, MATNEST, &matnest));
1979: if (jac->defaultsplit && !matnest) {
1980: PetscCall(VecGetBlockSize(x, &bs));
1981: 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);
1982: PetscCall(VecGetBlockSize(y, &bs));
1983: 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);
1984: PetscCall(VecStrideGatherAll(x, jac->x, INSERT_VALUES));
1985: while (ilink) {
1986: PetscCall(PetscLogEventBegin(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1987: PetscCall(KSPSolveTranspose(ilink->ksp, ilink->x, ilink->y));
1988: PetscCall(KSPCheckSolve(ilink->ksp, pc, ilink->y));
1989: PetscCall(PetscLogEventEnd(ilink->event, ilink->ksp, ilink->x, ilink->y, NULL));
1990: ilink = ilink->next;
1991: }
1992: PetscCall(VecStrideScatterAll(jac->y, y, INSERT_VALUES));
1993: } else {
1994: PetscCall(VecSet(y, 0.0));
1995: while (ilink) {
1996: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
1997: ilink = ilink->next;
1998: }
1999: }
2000: } else {
2001: if (!jac->w1) {
2002: PetscCall(VecDuplicate(x, &jac->w1));
2003: PetscCall(VecDuplicate(x, &jac->w2));
2004: }
2005: PetscCall(VecSet(y, 0.0));
2006: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
2007: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
2008: while (ilink->next) {
2009: ilink = ilink->next;
2010: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
2011: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
2012: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
2013: }
2014: while (ilink->previous) {
2015: ilink = ilink->previous;
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: } else {
2021: while (ilink->next) { /* get to last entry in linked list */
2022: ilink = ilink->next;
2023: }
2024: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, x, y));
2025: while (ilink->previous) {
2026: ilink = ilink->previous;
2027: PetscCall(MatMultTranspose(pc->mat, y, jac->w1));
2028: PetscCall(VecWAXPY(jac->w2, -1.0, jac->w1, x));
2029: PetscCall(FieldSplitSplitSolveAddTranspose(ilink, jac->w2, y));
2030: }
2031: }
2032: }
2033: PetscFunctionReturn(PETSC_SUCCESS);
2034: }
2036: static PetscErrorCode PCReset_FieldSplit(PC pc)
2037: {
2038: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2039: PC_FieldSplitLink ilink = jac->head, next;
2041: PetscFunctionBegin;
2042: while (ilink) {
2043: PetscCall(KSPDestroy(&ilink->ksp));
2044: PetscCall(VecDestroy(&ilink->x));
2045: PetscCall(VecDestroy(&ilink->y));
2046: PetscCall(VecDestroy(&ilink->z));
2047: PetscCall(MatDestroy(&ilink->X));
2048: PetscCall(MatDestroy(&ilink->Y));
2049: PetscCall(MatDestroy(&ilink->Z));
2050: PetscCall(VecScatterDestroy(&ilink->sctx));
2051: PetscCall(ISDestroy(&ilink->is));
2052: PetscCall(ISDestroy(&ilink->is_col));
2053: PetscCall(PetscFree(ilink->splitname));
2054: PetscCall(PetscFree(ilink->fields));
2055: PetscCall(PetscFree(ilink->fields_col));
2056: next = ilink->next;
2057: PetscCall(PetscFree(ilink));
2058: ilink = next;
2059: }
2060: jac->head = NULL;
2061: PetscCall(PetscFree2(jac->x, jac->y));
2062: if (jac->mat && jac->mat != jac->pmat) {
2063: PetscCall(MatDestroyMatrices(jac->nsplits, &jac->mat));
2064: } else if (jac->mat) {
2065: jac->mat = NULL;
2066: }
2067: if (jac->pmat) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->pmat));
2068: if (jac->Afield) PetscCall(MatDestroyMatrices(jac->nsplits, &jac->Afield));
2069: jac->nsplits = 0;
2070: PetscCall(VecDestroy(&jac->w1));
2071: PetscCall(VecDestroy(&jac->w2));
2072: if (jac->schur) PetscCall(PetscObjectCompose((PetscObject)jac->schur, "AinvB", NULL));
2073: PetscCall(MatDestroy(&jac->schur));
2074: PetscCall(MatDestroy(&jac->schurp));
2075: PetscCall(MatDestroy(&jac->schur_user));
2076: PetscCall(KSPDestroy(&jac->kspschur));
2077: PetscCall(KSPDestroy(&jac->kspupper));
2078: PetscCall(MatDestroy(&jac->B));
2079: PetscCall(MatDestroy(&jac->C));
2080: PetscCall(MatDestroy(&jac->H));
2081: PetscCall(VecDestroy(&jac->u));
2082: PetscCall(VecDestroy(&jac->v));
2083: PetscCall(VecDestroy(&jac->Hu));
2084: PetscCall(VecDestroy(&jac->d));
2085: PetscCall(PetscFree(jac->vecz));
2086: PetscCall(PetscViewerDestroy(&jac->gkbviewer));
2087: jac->isrestrict = PETSC_FALSE;
2088: PetscFunctionReturn(PETSC_SUCCESS);
2089: }
2091: static PetscErrorCode PCDestroy_FieldSplit(PC pc)
2092: {
2093: PetscFunctionBegin;
2094: PetscCall(PCReset_FieldSplit(pc));
2095: PetscCall(PetscFree(pc->data));
2096: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", NULL));
2097: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", NULL));
2098: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", NULL));
2099: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", NULL));
2100: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", NULL));
2101: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", NULL));
2102: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", NULL));
2103: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
2104: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
2105: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
2106: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
2107: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
2108: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
2109: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
2110: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
2111: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
2112: PetscFunctionReturn(PETSC_SUCCESS);
2113: }
2115: static PetscErrorCode PCSetFromOptions_FieldSplit(PC pc, PetscOptionItems PetscOptionsObject)
2116: {
2117: PetscInt bs;
2118: PetscBool flg;
2119: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2120: PCCompositeType ctype;
2122: PetscFunctionBegin;
2123: PetscOptionsHeadBegin(PetscOptionsObject, "FieldSplit options");
2124: PetscCall(PetscOptionsBool("-pc_fieldsplit_dm_splits", "Whether to use DMCreateFieldDecomposition() for splits", "PCFieldSplitSetDMSplits", jac->dm_splits, &jac->dm_splits, NULL));
2125: PetscCall(PetscOptionsInt("-pc_fieldsplit_block_size", "Blocksize that defines number of fields", "PCFieldSplitSetBlockSize", jac->bs, &bs, &flg));
2126: if (flg) PetscCall(PCFieldSplitSetBlockSize(pc, bs));
2127: jac->diag_use_amat = pc->useAmat;
2128: 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));
2129: jac->offdiag_use_amat = pc->useAmat;
2130: 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));
2131: PetscCall(PetscOptionsBool("-pc_fieldsplit_detect_saddle_point", "Form 2-way split by detecting zero diagonal entries", "PCFieldSplitSetDetectSaddlePoint", jac->detect, &jac->detect, NULL));
2132: PetscCall(PCFieldSplitSetDetectSaddlePoint(pc, jac->detect)); /* Sets split type and Schur PC type */
2133: PetscCall(PetscOptionsEnum("-pc_fieldsplit_type", "Type of composition", "PCFieldSplitSetType", PCCompositeTypes, (PetscEnum)jac->type, (PetscEnum *)&ctype, &flg));
2134: if (flg) PetscCall(PCFieldSplitSetType(pc, ctype));
2135: /* Only setup fields once */
2136: if (jac->bs > 0 && jac->nsplits == 0) {
2137: /* only allow user to set fields from command line.
2138: otherwise user can set them in PCFieldSplitSetDefaults() */
2139: PetscCall(PCFieldSplitSetRuntimeSplits_Private(pc));
2140: if (jac->splitdefined) PetscCall(PetscInfo(pc, "Splits defined using the options database\n"));
2141: }
2142: if (jac->type == PC_COMPOSITE_SCHUR) {
2143: PetscCall(PetscOptionsGetEnum(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_fieldsplit_schur_factorization_type", PCFieldSplitSchurFactTypes, (PetscEnum *)&jac->schurfactorization, &flg));
2144: if (flg) PetscCall(PetscInfo(pc, "Deprecated use of -pc_fieldsplit_schur_factorization_type\n"));
2145: 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));
2146: PetscCall(PetscOptionsEnum("-pc_fieldsplit_schur_precondition", "How to build preconditioner for Schur complement", "PCFieldSplitSetSchurPre", PCFieldSplitSchurPreTypes, (PetscEnum)jac->schurpre, (PetscEnum *)&jac->schurpre, NULL));
2147: PetscCall(PetscOptionsScalar("-pc_fieldsplit_schur_scale", "Scale Schur complement", "PCFieldSplitSetSchurScale", jac->schurscale, &jac->schurscale, NULL));
2148: } else if (jac->type == PC_COMPOSITE_GKB) {
2149: PetscCall(PetscOptionsReal("-pc_fieldsplit_gkb_tol", "The tolerance for the lower bound stopping criterion", "PCFieldSplitSetGKBTol", jac->gkbtol, &jac->gkbtol, NULL));
2150: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_delay", "The delay value for lower bound criterion", "PCFieldSplitSetGKBDelay", jac->gkbdelay, &jac->gkbdelay, NULL));
2151: PetscCall(PetscOptionsBoundedReal("-pc_fieldsplit_gkb_nu", "Parameter in augmented Lagrangian approach", "PCFieldSplitSetGKBNu", jac->gkbnu, &jac->gkbnu, NULL, 0.0));
2152: PetscCall(PetscOptionsInt("-pc_fieldsplit_gkb_maxit", "Maximum allowed number of iterations", "PCFieldSplitSetGKBMaxit", jac->gkbmaxit, &jac->gkbmaxit, NULL));
2153: PetscCall(PetscOptionsBool("-pc_fieldsplit_gkb_monitor", "Prints number of GKB iterations and error", "PCFieldSplitGKB", jac->gkbmonitor, &jac->gkbmonitor, NULL));
2154: }
2155: /*
2156: In the initial call to this routine the sub-solver data structures do not exist so we cannot call KSPSetFromOptions() on them yet.
2157: 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
2158: is called on the outer solver in case changes were made in the options database
2160: 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()
2161: 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.
2162: Without this extra check test p2p1fetidp_olof_full and others fail with incorrect matrix types.
2164: There could be a negative side effect of calling the KSPSetFromOptions() below.
2166: If one captured the PetscObjectState of the options database one could skip these calls if the database has not changed from the previous call
2167: */
2168: if (jac->issetup) {
2169: PC_FieldSplitLink ilink = jac->head;
2170: if (jac->type == PC_COMPOSITE_SCHUR) {
2171: if (jac->kspupper && jac->kspupper->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspupper));
2172: if (jac->kspschur && jac->kspschur->totalits > 0) PetscCall(KSPSetFromOptions(jac->kspschur));
2173: }
2174: while (ilink) {
2175: if (ilink->ksp->totalits > 0) PetscCall(KSPSetFromOptions(ilink->ksp));
2176: ilink = ilink->next;
2177: }
2178: }
2179: PetscOptionsHeadEnd();
2180: PetscFunctionReturn(PETSC_SUCCESS);
2181: }
2183: static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc, const char splitname[], PetscInt n, const PetscInt *fields, const PetscInt *fields_col)
2184: {
2185: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2186: PC_FieldSplitLink ilink, next = jac->head;
2187: char prefix[128];
2188: PetscInt i;
2189: PetscLogEvent nse;
2191: PetscFunctionBegin;
2192: if (jac->splitdefined) {
2193: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
2194: PetscFunctionReturn(PETSC_SUCCESS);
2195: }
2196: for (i = 0; i < n; i++) PetscCheck(fields[i] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", fields[i]);
2197: PetscCall(PetscNew(&ilink));
2198: if (splitname) {
2199: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
2200: } else {
2201: PetscCall(PetscMalloc1(3, &ilink->splitname));
2202: PetscCall(PetscSNPrintf(ilink->splitname, 2, "%" PetscInt_FMT, jac->nsplits));
2203: }
2204: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
2205: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
2206: PetscCall(PetscMalloc1(n, &ilink->fields));
2207: PetscCall(PetscArraycpy(ilink->fields, fields, n));
2208: PetscCall(PetscMalloc1(n, &ilink->fields_col));
2209: PetscCall(PetscArraycpy(ilink->fields_col, fields_col, n));
2211: ilink->nfields = n;
2212: ilink->next = NULL;
2213: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
2214: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
2215: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
2216: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
2217: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
2219: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
2220: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
2222: if (!next) {
2223: jac->head = ilink;
2224: ilink->previous = NULL;
2225: } else {
2226: while (next->next) next = next->next;
2227: next->next = ilink;
2228: ilink->previous = next;
2229: }
2230: jac->nsplits++;
2231: PetscFunctionReturn(PETSC_SUCCESS);
2232: }
2234: static PetscErrorCode PCFieldSplitSchurGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
2235: {
2236: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2238: PetscFunctionBegin;
2239: *subksp = NULL;
2240: if (n) *n = 0;
2241: if (jac->type == PC_COMPOSITE_SCHUR) {
2242: PetscInt nn;
2244: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitSchurGetSubKSP()");
2245: PetscCheck(jac->nsplits == 2, PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "Unexpected number of splits %" PetscInt_FMT " != 2", jac->nsplits);
2246: nn = jac->nsplits + (jac->kspupper != jac->head->ksp ? 1 : 0);
2247: PetscCall(PetscMalloc1(nn, subksp));
2248: (*subksp)[0] = jac->head->ksp;
2249: (*subksp)[1] = jac->kspschur;
2250: if (jac->kspupper != jac->head->ksp) (*subksp)[2] = jac->kspupper;
2251: if (n) *n = nn;
2252: }
2253: PetscFunctionReturn(PETSC_SUCCESS);
2254: }
2256: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc, PetscInt *n, KSP **subksp)
2257: {
2258: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2260: PetscFunctionBegin;
2261: PetscCheck(jac->schur, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitGetSubKSP()");
2262: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2263: PetscCall(MatSchurComplementGetKSP(jac->schur, *subksp));
2265: (*subksp)[1] = jac->kspschur;
2266: if (n) *n = jac->nsplits;
2267: PetscFunctionReturn(PETSC_SUCCESS);
2268: }
2270: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc, PetscInt *n, KSP **subksp)
2271: {
2272: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2273: PetscInt cnt = 0;
2274: PC_FieldSplitLink ilink = jac->head;
2276: PetscFunctionBegin;
2277: PetscCall(PetscMalloc1(jac->nsplits, subksp));
2278: while (ilink) {
2279: (*subksp)[cnt++] = ilink->ksp;
2280: ilink = ilink->next;
2281: }
2282: 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);
2283: if (n) *n = jac->nsplits;
2284: PetscFunctionReturn(PETSC_SUCCESS);
2285: }
2287: /*@
2288: PCFieldSplitRestrictIS - Restricts the fieldsplit `IS`s to be within a given `IS`.
2290: Input Parameters:
2291: + pc - the preconditioner context
2292: - isy - the index set that defines the indices to which the fieldsplit is to be restricted
2294: Level: advanced
2296: Developer Notes:
2297: It seems the resulting `IS`s will not cover the entire space, so
2298: how can they define a convergent preconditioner? Needs explaining.
2300: .seealso: [](sec_block_matrices), `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2301: @*/
2302: PetscErrorCode PCFieldSplitRestrictIS(PC pc, IS isy)
2303: {
2304: PetscFunctionBegin;
2307: PetscTryMethod(pc, "PCFieldSplitRestrictIS_C", (PC, IS), (pc, isy));
2308: PetscFunctionReturn(PETSC_SUCCESS);
2309: }
2311: static PetscErrorCode PCFieldSplitRestrictIS_FieldSplit(PC pc, IS isy)
2312: {
2313: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2314: PC_FieldSplitLink ilink = jac->head, next;
2315: PetscInt localsize, size, sizez, i;
2316: const PetscInt *ind, *indz;
2317: PetscInt *indc, *indcz;
2318: PetscBool flg;
2320: PetscFunctionBegin;
2321: PetscCall(ISGetLocalSize(isy, &localsize));
2322: PetscCallMPI(MPI_Scan(&localsize, &size, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)isy)));
2323: size -= localsize;
2324: while (ilink) {
2325: IS isrl, isr;
2326: PC subpc;
2327: PetscCall(ISEmbed(ilink->is, isy, PETSC_TRUE, &isrl));
2328: PetscCall(ISGetLocalSize(isrl, &localsize));
2329: PetscCall(PetscMalloc1(localsize, &indc));
2330: PetscCall(ISGetIndices(isrl, &ind));
2331: PetscCall(PetscArraycpy(indc, ind, localsize));
2332: PetscCall(ISRestoreIndices(isrl, &ind));
2333: PetscCall(ISDestroy(&isrl));
2334: for (i = 0; i < localsize; i++) *(indc + i) += size;
2335: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)isy), localsize, indc, PETSC_OWN_POINTER, &isr));
2336: PetscCall(PetscObjectReference((PetscObject)isr));
2337: PetscCall(ISDestroy(&ilink->is));
2338: ilink->is = isr;
2339: PetscCall(PetscObjectReference((PetscObject)isr));
2340: PetscCall(ISDestroy(&ilink->is_col));
2341: ilink->is_col = isr;
2342: PetscCall(ISDestroy(&isr));
2343: PetscCall(KSPGetPC(ilink->ksp, &subpc));
2344: PetscCall(PetscObjectTypeCompare((PetscObject)subpc, PCFIELDSPLIT, &flg));
2345: if (flg) {
2346: IS iszl, isz;
2347: MPI_Comm comm;
2348: PetscCall(ISGetLocalSize(ilink->is, &localsize));
2349: comm = PetscObjectComm((PetscObject)ilink->is);
2350: PetscCall(ISEmbed(isy, ilink->is, PETSC_TRUE, &iszl));
2351: PetscCallMPI(MPI_Scan(&localsize, &sizez, 1, MPIU_INT, MPI_SUM, comm));
2352: sizez -= localsize;
2353: PetscCall(ISGetLocalSize(iszl, &localsize));
2354: PetscCall(PetscMalloc1(localsize, &indcz));
2355: PetscCall(ISGetIndices(iszl, &indz));
2356: PetscCall(PetscArraycpy(indcz, indz, localsize));
2357: PetscCall(ISRestoreIndices(iszl, &indz));
2358: PetscCall(ISDestroy(&iszl));
2359: for (i = 0; i < localsize; i++) *(indcz + i) += sizez;
2360: PetscCall(ISCreateGeneral(comm, localsize, indcz, PETSC_OWN_POINTER, &isz));
2361: PetscCall(PCFieldSplitRestrictIS(subpc, isz));
2362: PetscCall(ISDestroy(&isz));
2363: }
2364: next = ilink->next;
2365: ilink = next;
2366: }
2367: jac->isrestrict = PETSC_TRUE;
2368: PetscFunctionReturn(PETSC_SUCCESS);
2369: }
2371: static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc, const char splitname[], IS is)
2372: {
2373: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2374: PC_FieldSplitLink ilink, next = jac->head;
2375: char prefix[128];
2376: PetscLogEvent nse;
2378: PetscFunctionBegin;
2379: if (jac->splitdefined) {
2380: PetscCall(PetscInfo(pc, "Ignoring new split \"%s\" because the splits have already been defined\n", splitname));
2381: PetscFunctionReturn(PETSC_SUCCESS);
2382: }
2383: PetscCall(PetscNew(&ilink));
2384: if (splitname) {
2385: PetscCall(PetscStrallocpy(splitname, &ilink->splitname));
2386: } else {
2387: PetscCall(PetscMalloc1(8, &ilink->splitname));
2388: PetscCall(PetscSNPrintf(ilink->splitname, 7, "%" PetscInt_FMT, jac->nsplits));
2389: }
2390: PetscCall(PetscMPIIntCast(jac->nsplits, &nse));
2391: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + nse : KSP_Solve_FS_0 + 4; /* Splits greater than 4 logged in 4th split */
2392: PetscCall(PetscObjectReference((PetscObject)is));
2393: PetscCall(ISDestroy(&ilink->is));
2394: ilink->is = is;
2395: PetscCall(PetscObjectReference((PetscObject)is));
2396: PetscCall(ISDestroy(&ilink->is_col));
2397: ilink->is_col = is;
2398: ilink->next = NULL;
2399: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &ilink->ksp));
2400: PetscCall(KSPSetNestLevel(ilink->ksp, pc->kspnestlevel));
2401: PetscCall(KSPSetErrorIfNotConverged(ilink->ksp, pc->erroriffailure));
2402: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->ksp, (PetscObject)pc, 1));
2403: PetscCall(KSPSetType(ilink->ksp, KSPPREONLY));
2405: PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname));
2406: PetscCall(KSPSetOptionsPrefix(ilink->ksp, prefix));
2408: if (!next) {
2409: jac->head = ilink;
2410: ilink->previous = NULL;
2411: } else {
2412: while (next->next) next = next->next;
2413: next->next = ilink;
2414: ilink->previous = next;
2415: }
2416: jac->nsplits++;
2417: PetscFunctionReturn(PETSC_SUCCESS);
2418: }
2420: /*@
2421: PCFieldSplitSetFields - Sets the fields that define one particular split in `PCFIELDSPLIT`
2423: Logically Collective
2425: Input Parameters:
2426: + pc - the preconditioner context
2427: . splitname - name of this split, if `NULL` the number of the split is used
2428: . n - the number of fields in this split
2429: . fields - the fields in this split
2430: - 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
2431: of the matrix and `fields_col` provides the column indices for that block
2433: Options Database Key:
2434: . -pc_fieldsplit_%d_fields a,b,... - indicates the fields to be used in the `%d`'th split
2436: Level: intermediate
2438: Notes:
2439: Use `PCFieldSplitSetIS()` to set a general set of indices as a split.
2441: If the matrix used to construct the preconditioner is `MATNEST` then field i refers to the `is_row[i]` `IS` passed to `MatCreateNest()`.
2443: If the matrix used to construct the preconditioner is not `MATNEST` then
2444: `PCFieldSplitSetFields()` is for defining fields as strided blocks (based on the block size provided to the matrix with `MatSetBlockSize()` or
2445: to the `PC` with `PCFieldSplitSetBlockSize()`). For example, if the block
2446: 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
2447: 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x23x56x8.. x12x45x78x....
2448: where the numbered entries indicate what is in the split.
2450: This function is called once per split (it creates a new split each time). Solve options
2451: for this split will be available under the prefix `-fieldsplit_SPLITNAME_`.
2453: `PCFieldSplitSetIS()` does not support having a `fields_col` different from `fields`
2455: Developer Notes:
2456: This routine does not actually create the `IS` representing the split, that is delayed
2457: until `PCSetUp_FieldSplit()`, because information about the vector/matrix layouts may not be
2458: available when this routine is called.
2460: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetIS()`, `PCFieldSplitRestrictIS()`,
2461: `MatSetBlockSize()`, `MatCreateNest()`
2462: @*/
2463: PetscErrorCode PCFieldSplitSetFields(PC pc, const char splitname[], PetscInt n, const PetscInt fields[], const PetscInt fields_col[])
2464: {
2465: PetscFunctionBegin;
2467: PetscAssertPointer(splitname, 2);
2468: PetscCheck(n >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Provided number of fields %" PetscInt_FMT " in split \"%s\" not positive", n, splitname);
2469: PetscAssertPointer(fields, 4);
2470: PetscTryMethod(pc, "PCFieldSplitSetFields_C", (PC, const char[], PetscInt, const PetscInt *, const PetscInt *), (pc, splitname, n, fields, fields_col));
2471: PetscFunctionReturn(PETSC_SUCCESS);
2472: }
2474: /*@
2475: PCFieldSplitSetDiagUseAmat - set flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2476: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2478: Logically Collective
2480: Input Parameters:
2481: + pc - the preconditioner object
2482: - flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2484: Options Database Key:
2485: . -pc_fieldsplit_diag_use_amat - use the Amat to provide the diagonal blocks
2487: Level: intermediate
2489: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetDiagUseAmat()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFIELDSPLIT`
2490: @*/
2491: PetscErrorCode PCFieldSplitSetDiagUseAmat(PC pc, PetscBool flg)
2492: {
2493: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2494: PetscBool isfs;
2496: PetscFunctionBegin;
2498: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2499: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2500: jac->diag_use_amat = flg;
2501: PetscFunctionReturn(PETSC_SUCCESS);
2502: }
2504: /*@
2505: PCFieldSplitGetDiagUseAmat - get the flag indicating whether to extract diagonal blocks from Amat (rather than Pmat) to build
2506: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2508: Logically Collective
2510: Input Parameter:
2511: . pc - the preconditioner object
2513: Output Parameter:
2514: . flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
2516: Level: intermediate
2518: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetDiagUseAmat()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFIELDSPLIT`
2519: @*/
2520: PetscErrorCode PCFieldSplitGetDiagUseAmat(PC pc, PetscBool *flg)
2521: {
2522: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2523: PetscBool isfs;
2525: PetscFunctionBegin;
2527: PetscAssertPointer(flg, 2);
2528: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2529: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2530: *flg = jac->diag_use_amat;
2531: PetscFunctionReturn(PETSC_SUCCESS);
2532: }
2534: /*@
2535: PCFieldSplitSetOffDiagUseAmat - set flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2536: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2538: Logically Collective
2540: Input Parameters:
2541: + pc - the preconditioner object
2542: - flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2544: Options Database Key:
2545: . -pc_fieldsplit_off_diag_use_amat (true|false) - use the Amat to extract the off-diagonal blocks
2547: Level: intermediate
2549: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitGetOffDiagUseAmat()`, `PCFieldSplitSetDiagUseAmat()`, `PCFIELDSPLIT`
2550: @*/
2551: PetscErrorCode PCFieldSplitSetOffDiagUseAmat(PC pc, PetscBool flg)
2552: {
2553: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2554: PetscBool isfs;
2556: PetscFunctionBegin;
2558: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2559: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2560: jac->offdiag_use_amat = flg;
2561: PetscFunctionReturn(PETSC_SUCCESS);
2562: }
2564: /*@
2565: PCFieldSplitGetOffDiagUseAmat - get the flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat) to build
2566: the sub-matrices associated with each split. Where `KSPSetOperators`(ksp,Amat,Pmat) was used to supply the operators.
2568: Logically Collective
2570: Input Parameter:
2571: . pc - the preconditioner object
2573: Output Parameter:
2574: . flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
2576: Level: intermediate
2578: .seealso: [](sec_block_matrices), `PC`, `PCSetOperators()`, `KSPSetOperators()`, `PCFieldSplitSetOffDiagUseAmat()`, `PCFieldSplitGetDiagUseAmat()`, `PCFIELDSPLIT`
2579: @*/
2580: PetscErrorCode PCFieldSplitGetOffDiagUseAmat(PC pc, PetscBool *flg)
2581: {
2582: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2583: PetscBool isfs;
2585: PetscFunctionBegin;
2587: PetscAssertPointer(flg, 2);
2588: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
2589: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "PC not of type %s", PCFIELDSPLIT);
2590: *flg = jac->offdiag_use_amat;
2591: PetscFunctionReturn(PETSC_SUCCESS);
2592: }
2594: /*@
2595: PCFieldSplitSetIS - Sets the exact elements for a split in a `PCFIELDSPLIT`
2597: Logically Collective
2599: Input Parameters:
2600: + pc - the preconditioner context
2601: . splitname - name of this split, if `NULL` the number of the split is used
2602: - is - the index set that defines the elements in this split
2604: Level: intermediate
2606: Notes:
2607: Use `PCFieldSplitSetFields()`, for splits defined by strided `IS` based on the matrix block size or the `is_rows[]` passed into `MATNEST`
2609: This function is called once per split (it creates a new split each time). Solve options
2610: for this split will be available under the prefix -fieldsplit_SPLITNAME_.
2612: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetBlockSize()`, `PCFieldSplitSetFields()`
2613: @*/
2614: PetscErrorCode PCFieldSplitSetIS(PC pc, const char splitname[], IS is)
2615: {
2616: PetscFunctionBegin;
2618: if (splitname) PetscAssertPointer(splitname, 2);
2620: PetscTryMethod(pc, "PCFieldSplitSetIS_C", (PC, const char[], IS), (pc, splitname, is));
2621: PetscFunctionReturn(PETSC_SUCCESS);
2622: }
2624: /*@
2625: PCFieldSplitGetIS - Retrieves the elements for a split as an `IS`
2627: Logically Collective
2629: Input Parameters:
2630: + pc - the preconditioner context
2631: - splitname - name of this split
2633: Output Parameter:
2634: . is - the index set that defines the elements in this split, or `NULL` if the split is not found
2636: Level: intermediate
2638: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetIS()`, `PCFieldSplitGetISByIndex()`
2639: @*/
2640: PetscErrorCode PCFieldSplitGetIS(PC pc, const char splitname[], IS *is)
2641: {
2642: PetscFunctionBegin;
2644: PetscAssertPointer(splitname, 2);
2645: PetscAssertPointer(is, 3);
2646: {
2647: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2648: PC_FieldSplitLink ilink = jac->head;
2649: PetscBool found;
2651: *is = NULL;
2652: while (ilink) {
2653: PetscCall(PetscStrcmp(ilink->splitname, splitname, &found));
2654: if (found) {
2655: *is = ilink->is;
2656: break;
2657: }
2658: ilink = ilink->next;
2659: }
2660: }
2661: PetscFunctionReturn(PETSC_SUCCESS);
2662: }
2664: /*@
2665: PCFieldSplitGetISByIndex - Retrieves the elements for a given split as an `IS`
2667: Logically Collective
2669: Input Parameters:
2670: + pc - the preconditioner context
2671: - index - index of this split
2673: Output Parameter:
2674: . is - the index set that defines the elements in this split
2676: Level: intermediate
2678: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitGetIS()`, `PCFieldSplitSetIS()`
2679: @*/
2680: PetscErrorCode PCFieldSplitGetISByIndex(PC pc, PetscInt index, IS *is)
2681: {
2682: PetscFunctionBegin;
2683: PetscCheck(index >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative field %" PetscInt_FMT " requested", index);
2685: PetscAssertPointer(is, 3);
2686: {
2687: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2688: PC_FieldSplitLink ilink = jac->head;
2689: PetscInt i = 0;
2690: PetscCheck(index < jac->nsplits, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " requested but only %" PetscInt_FMT " exist", index, jac->nsplits);
2692: while (i < index) {
2693: ilink = ilink->next;
2694: ++i;
2695: }
2696: PetscCall(PCFieldSplitGetIS(pc, ilink->splitname, is));
2697: }
2698: PetscFunctionReturn(PETSC_SUCCESS);
2699: }
2701: /*@
2702: PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the
2703: fieldsplit preconditioner when calling `PCFieldSplitSetFields()`. If not set the matrix block size is used.
2705: Logically Collective
2707: Input Parameters:
2708: + pc - the preconditioner context
2709: - bs - the block size
2711: Level: intermediate
2713: Note:
2714: If the matrix is a `MATNEST` then the `is_rows[]` passed to `MatCreateNest()` determines the fields.
2716: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
2717: @*/
2718: PetscErrorCode PCFieldSplitSetBlockSize(PC pc, PetscInt bs)
2719: {
2720: PetscFunctionBegin;
2723: PetscTryMethod(pc, "PCFieldSplitSetBlockSize_C", (PC, PetscInt), (pc, bs));
2724: PetscFunctionReturn(PETSC_SUCCESS);
2725: }
2727: /*@
2728: PCFieldSplitGetSubKSP - Gets the `KSP` contexts for all splits
2730: Collective
2732: Input Parameter:
2733: . pc - the preconditioner context
2735: Output Parameters:
2736: + n - the number of splits
2737: - subksp - the array of `KSP` contexts
2739: Level: advanced
2741: Notes:
2742: After `PCFieldSplitGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2743: (not the `KSP`, just the array that contains them).
2745: You must call `PCSetUp()` before calling `PCFieldSplitGetSubKSP()`.
2747: If the fieldsplit is of type `PC_COMPOSITE_SCHUR`, it returns the `KSP` object used inside the
2748: Schur complement and the `KSP` object used to iterate over the Schur complement.
2749: To access all the `KSP` objects used in `PC_COMPOSITE_SCHUR`, use `PCFieldSplitSchurGetSubKSP()`.
2751: If the fieldsplit is of type `PC_COMPOSITE_GKB`, it returns the `KSP` object used to solve the
2752: inner linear system defined by the matrix H in each loop.
2754: Fortran Note:
2755: Call `PCFieldSplitRestoreSubKSP()` when the array of `KSP` is no longer needed
2757: Developer Notes:
2758: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2760: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitSchurGetSubKSP()`
2761: @*/
2762: PetscErrorCode PCFieldSplitGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2763: {
2764: PetscFunctionBegin;
2766: if (n) PetscAssertPointer(n, 2);
2767: PetscUseMethod(pc, "PCFieldSplitGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2768: PetscFunctionReturn(PETSC_SUCCESS);
2769: }
2771: /*@
2772: PCFieldSplitSchurGetSubKSP - Gets the `KSP` contexts used inside the Schur complement based `PCFIELDSPLIT`
2774: Collective
2776: Input Parameter:
2777: . pc - the preconditioner context
2779: Output Parameters:
2780: + n - the number of splits
2781: - subksp - the array of `KSP` contexts
2783: Level: advanced
2785: Notes:
2786: After `PCFieldSplitSchurGetSubKSP()` the array of `KSP`s is to be freed by the user with `PetscFree()`
2787: (not the `KSP` just the array that contains them).
2789: You must call `PCSetUp()` before calling `PCFieldSplitSchurGetSubKSP()`.
2791: If the fieldsplit type is of type `PC_COMPOSITE_SCHUR`, it returns (in order)
2792: + 1 - the `KSP` used for the (1,1) block
2793: . 2 - the `KSP` used for the Schur complement (not the one used for the interior Schur solver)
2794: - 3 - the `KSP` used for the (1,1) block in the upper triangular factor (if different from that of the (1,1) block).
2796: It returns a null array if the fieldsplit is not of type `PC_COMPOSITE_SCHUR`; in this case, you should use `PCFieldSplitGetSubKSP()`.
2798: Fortran Note:
2799: Call `PCFieldSplitSchurRestoreSubKSP()` when the array of `KSP` is no longer needed
2801: Developer Notes:
2802: There should be a `PCFieldSplitRestoreSubKSP()` instead of requiring the user to call `PetscFree()`
2804: Should the functionality of `PCFieldSplitSchurGetSubKSP()` and `PCFieldSplitGetSubKSP()` be merged?
2806: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`, `PCFieldSplitGetSubKSP()`
2807: @*/
2808: PetscErrorCode PCFieldSplitSchurGetSubKSP(PC pc, PetscInt *n, KSP *subksp[])
2809: {
2810: PetscFunctionBegin;
2812: if (n) PetscAssertPointer(n, 2);
2813: PetscUseMethod(pc, "PCFieldSplitSchurGetSubKSP_C", (PC, PetscInt *, KSP **), (pc, n, subksp));
2814: PetscFunctionReturn(PETSC_SUCCESS);
2815: }
2817: /*@
2818: PCFieldSplitSetSchurPre - Indicates from what operator the preconditioner is constructed for the Schur complement.
2819: The default is the A11 matrix.
2821: Collective
2823: Input Parameters:
2824: + pc - the preconditioner context
2825: . ptype - which matrix to use for preconditioning the Schur complement: `PC_FIELDSPLIT_SCHUR_PRE_A11` (default),
2826: `PC_FIELDSPLIT_SCHUR_PRE_SELF`, `PC_FIELDSPLIT_SCHUR_PRE_USER`,
2827: `PC_FIELDSPLIT_SCHUR_PRE_SELFP`, and `PC_FIELDSPLIT_SCHUR_PRE_FULL`
2828: - pre - matrix to use for preconditioning, or `NULL`
2830: Options Database Keys:
2831: + -pc_fieldsplit_schur_precondition (self|selfp|user|a11|full) - default is `a11`. See notes for meaning of various arguments
2832: - -fieldsplit_1_pc_type pctype - the preconditioner algorithm that is used to construct the preconditioner from the operator
2834: Level: intermediate
2836: Notes:
2837: If ptype is
2838: + a11 - the preconditioner for the Schur complement is generated from the block diagonal part of the preconditioner
2839: matrix associated with the Schur complement (i.e. A11), not the Schur complement matrix
2840: . self - the preconditioner for the Schur complement is generated from the symbolic representation of the Schur complement matrix:
2841: The only preconditioners that currently work with this symbolic representation matrix object are `PCLSC` and `PCHPDDM`
2842: . user - the preconditioner for the Schur complement is generated from the user provided matrix (pre argument
2843: to this function).
2844: . selfp - the preconditioning for the Schur complement is generated from an explicitly-assembled approximation $ Sp = A11 - A10 inv(diag(A00)) A01 $
2845: This is only a good preconditioner when diag(A00) is a good preconditioner for A00. Optionally, A00 can be
2846: lumped before extracting the diagonal using the additional option `-fieldsplit_1_mat_schur_complement_ainv_type lump`
2847: - full - the preconditioner for the Schur complement is generated from the exact Schur complement matrix representation
2848: computed internally by `PCFIELDSPLIT` (this is expensive)
2849: useful mostly as a test that the Schur complement approach can work for your problem
2851: When solving a saddle point problem, where the A11 block is identically zero, using `a11` as the ptype only makes sense
2852: with the additional option `-fieldsplit_1_pc_type none`. Usually for saddle point problems one would use a `ptype` of `self` and
2853: `-fieldsplit_1_pc_type lsc` which uses the least squares commutator to compute a preconditioner for the Schur complement.
2855: Developer Note:
2856: The name of this function and the option `-pc_fieldsplit_schur_precondition` are inconsistent; precondition should be used everywhere.
2858: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`,
2859: `MatSchurComplementSetAinvType()`, `PCLSC`, `PCFieldSplitSetSchurFactType()`
2860: @*/
2861: PetscErrorCode PCFieldSplitSetSchurPre(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2862: {
2863: PetscFunctionBegin;
2865: PetscTryMethod(pc, "PCFieldSplitSetSchurPre_C", (PC, PCFieldSplitSchurPreType, Mat), (pc, ptype, pre));
2866: PetscFunctionReturn(PETSC_SUCCESS);
2867: }
2869: PetscErrorCode PCFieldSplitSchurPrecondition(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2870: {
2871: return PCFieldSplitSetSchurPre(pc, ptype, pre);
2872: } /* Deprecated name */
2874: /*@
2875: PCFieldSplitGetSchurPre - For Schur complement fieldsplit, determine how the Schur complement will be
2876: preconditioned. See `PCFieldSplitSetSchurPre()` for details.
2878: Logically Collective
2880: Input Parameter:
2881: . pc - the preconditioner context
2883: Output Parameters:
2884: + 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`
2885: - pre - matrix to use for preconditioning (with `PC_FIELDSPLIT_SCHUR_PRE_USER`), or `NULL`
2887: Level: intermediate
2889: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCLSC`
2890: @*/
2891: PetscErrorCode PCFieldSplitGetSchurPre(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2892: {
2893: PetscFunctionBegin;
2895: PetscUseMethod(pc, "PCFieldSplitGetSchurPre_C", (PC, PCFieldSplitSchurPreType *, Mat *), (pc, ptype, pre));
2896: PetscFunctionReturn(PETSC_SUCCESS);
2897: }
2899: /*@
2900: PCFieldSplitSchurGetS - extract the `MATSCHURCOMPLEMENT` object used by this `PCFIELDSPLIT` in case it needs to be configured separately
2902: Not Collective
2904: Input Parameter:
2905: . pc - the preconditioner context
2907: Output Parameter:
2908: . S - the Schur complement matrix
2910: Level: advanced
2912: Note:
2913: This matrix should not be destroyed using `MatDestroy()`; rather, use `PCFieldSplitSchurRestoreS()`.
2915: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MATSCHURCOMPLEMENT`, `PCFieldSplitSchurRestoreS()`,
2916: `MatCreateSchurComplement()`, `MatSchurComplementGetKSP()`, `MatSchurComplementComputeExplicitOperator()`, `MatGetSchurComplement()`
2917: @*/
2918: PetscErrorCode PCFieldSplitSchurGetS(PC pc, Mat *S)
2919: {
2920: const char *t;
2921: PetscBool isfs;
2922: PC_FieldSplit *jac;
2924: PetscFunctionBegin;
2926: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2927: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2928: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2929: jac = (PC_FieldSplit *)pc->data;
2930: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2931: if (S) *S = jac->schur;
2932: PetscFunctionReturn(PETSC_SUCCESS);
2933: }
2935: /*@
2936: PCFieldSplitSchurRestoreS - returns the `MATSCHURCOMPLEMENT` matrix used by this `PC`
2938: Not Collective
2940: Input Parameters:
2941: + pc - the preconditioner context
2942: - S - the Schur complement matrix
2944: Level: advanced
2946: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurPre()`, `MatSchurComplement`, `PCFieldSplitSchurGetS()`
2947: @*/
2948: PetscErrorCode PCFieldSplitSchurRestoreS(PC pc, Mat *S)
2949: {
2950: const char *t;
2951: PetscBool isfs;
2952: PC_FieldSplit *jac;
2954: PetscFunctionBegin;
2956: PetscCall(PetscObjectGetType((PetscObject)pc, &t));
2957: PetscCall(PetscStrcmp(t, PCFIELDSPLIT, &isfs));
2958: PetscCheck(isfs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PC of type PCFIELDSPLIT, got %s instead", t);
2959: jac = (PC_FieldSplit *)pc->data;
2960: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Expected PCFIELDSPLIT of type SCHUR, got %d instead", jac->type);
2961: PetscCheck(S && (*S == jac->schur), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MatSchurComplement restored is not the same as gotten");
2962: PetscFunctionReturn(PETSC_SUCCESS);
2963: }
2965: static PetscErrorCode PCFieldSplitSetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType ptype, Mat pre)
2966: {
2967: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2969: PetscFunctionBegin;
2970: jac->schurpre = ptype;
2971: if (ptype == PC_FIELDSPLIT_SCHUR_PRE_USER && pre) {
2972: PetscCall(MatDestroy(&jac->schur_user));
2973: jac->schur_user = pre;
2974: PetscCall(PetscObjectReference((PetscObject)jac->schur_user));
2975: }
2976: PetscFunctionReturn(PETSC_SUCCESS);
2977: }
2979: static PetscErrorCode PCFieldSplitGetSchurPre_FieldSplit(PC pc, PCFieldSplitSchurPreType *ptype, Mat *pre)
2980: {
2981: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
2983: PetscFunctionBegin;
2984: if (ptype) *ptype = jac->schurpre;
2985: if (pre) *pre = jac->schur_user;
2986: PetscFunctionReturn(PETSC_SUCCESS);
2987: }
2989: /*@
2990: PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain in the preconditioner {cite}`murphy2000note` and {cite}`ipsen2001note`
2992: Collective
2994: Input Parameters:
2995: + pc - the preconditioner context
2996: - ftype - which blocks of factorization to retain, `PC_FIELDSPLIT_SCHUR_FACT_FULL` is default
2998: Options Database Key:
2999: . -pc_fieldsplit_schur_fact_type (diag|lower|upper|full) - default is `full`
3001: Level: intermediate
3003: Notes:
3004: The `full` factorization is
3006: ```{math}
3007: \left(\begin{array}{cc} A & B \\
3008: C & E \\
3009: \end{array}\right) =
3010: \left(\begin{array}{cc} I & 0 \\
3011: C A^{-1} & I \\
3012: \end{array}\right)
3013: \left(\begin{array}{cc} A & 0 \\
3014: 0 & S \\
3015: \end{array}\right)
3016: \left(\begin{array}{cc} I & A^{-1}B \\
3017: 0 & I \\
3018: \end{array}\right) = L D U,
3019: ```
3021: 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 $LD$,
3022: and `diag` is the diagonal part with the sign of $S$ flipped (because this makes the preconditioner positive definite for many formulations,
3023: thus allowing the use of `KSPMINRES)`. Sign flipping of $S$ can be turned off with `PCFieldSplitSetSchurScale()`.
3025: If $A$ and $S$ are solved exactly
3026: + 1 - `full` factorization is a direct solver.
3027: . 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.
3028: - 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.
3030: If the iteration count is very low, consider using `KSPFGMRES` or `KSPGCR` which can use one less preconditioner
3031: application in this case. Note that the preconditioned operator may be highly non-normal, so such fast convergence may not be observed in practice.
3033: For symmetric problems in which $A$ is positive definite and $S$ is negative definite, `diag` can be used with `KSPMINRES`.
3035: 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 $S$).
3037: .seealso: [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurPreType`, `PCFieldSplitSetSchurScale()`,
3038: [](sec_flexibleksp), `PCFieldSplitSetSchurPre()`
3039: @*/
3040: PetscErrorCode PCFieldSplitSetSchurFactType(PC pc, PCFieldSplitSchurFactType ftype)
3041: {
3042: PetscFunctionBegin;
3044: PetscTryMethod(pc, "PCFieldSplitSetSchurFactType_C", (PC, PCFieldSplitSchurFactType), (pc, ftype));
3045: PetscFunctionReturn(PETSC_SUCCESS);
3046: }
3048: static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc, PCFieldSplitSchurFactType ftype)
3049: {
3050: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3052: PetscFunctionBegin;
3053: jac->schurfactorization = ftype;
3054: PetscFunctionReturn(PETSC_SUCCESS);
3055: }
3057: /*@
3058: PCFieldSplitSetSchurScale - Controls the sign flip of S for `PC_FIELDSPLIT_SCHUR_FACT_DIAG`.
3060: Collective
3062: Input Parameters:
3063: + pc - the preconditioner context
3064: - scale - scaling factor for the Schur complement
3066: Options Database Key:
3067: . -pc_fieldsplit_schur_scale scale - default is -1.0
3069: Level: intermediate
3071: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetFields()`, `PCFieldSplitSchurFactType`, `PCFieldSplitSetSchurFactType()`
3072: @*/
3073: PetscErrorCode PCFieldSplitSetSchurScale(PC pc, PetscScalar scale)
3074: {
3075: PetscFunctionBegin;
3078: PetscTryMethod(pc, "PCFieldSplitSetSchurScale_C", (PC, PetscScalar), (pc, scale));
3079: PetscFunctionReturn(PETSC_SUCCESS);
3080: }
3082: static PetscErrorCode PCFieldSplitSetSchurScale_FieldSplit(PC pc, PetscScalar scale)
3083: {
3084: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3086: PetscFunctionBegin;
3087: jac->schurscale = scale;
3088: PetscFunctionReturn(PETSC_SUCCESS);
3089: }
3091: /*@
3092: PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement
3094: Collective
3096: Input Parameter:
3097: . pc - the preconditioner context
3099: Output Parameters:
3100: + A00 - the (0,0) block
3101: . A01 - the (0,1) block
3102: . A10 - the (1,0) block
3103: - A11 - the (1,1) block
3105: Level: advanced
3107: Note:
3108: Use `NULL` for any unneeded output arguments
3110: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `MatSchurComplementGetSubMatrices()`, `MatSchurComplementSetSubMatrices()`
3111: @*/
3112: PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc, Mat *A00, Mat *A01, Mat *A10, Mat *A11)
3113: {
3114: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3116: PetscFunctionBegin;
3118: PetscCheck(jac->type == PC_COMPOSITE_SCHUR, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach.");
3119: if (A00) *A00 = jac->pmat[0];
3120: if (A01) *A01 = jac->B;
3121: if (A10) *A10 = jac->C;
3122: if (A11) *A11 = jac->pmat[1];
3123: PetscFunctionReturn(PETSC_SUCCESS);
3124: }
3126: /*@
3127: PCFieldSplitSetGKBTol - Sets the solver tolerance for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
3129: Collective
3131: Input Parameters:
3132: + pc - the preconditioner context
3133: - tolerance - the solver tolerance
3135: Options Database Key:
3136: . -pc_fieldsplit_gkb_tol tolerance - default is 1e-5
3138: Level: intermediate
3140: Note:
3141: The generalized GKB algorithm {cite}`arioli2013` uses a lower bound estimate of the error in energy norm as stopping criterion.
3142: It stops once the lower bound estimate undershoots the required solver tolerance. Although the actual error might be bigger than
3143: this estimate, the stopping criterion is satisfactory in practical cases.
3145: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBMaxit()`
3146: @*/
3147: PetscErrorCode PCFieldSplitSetGKBTol(PC pc, PetscReal tolerance)
3148: {
3149: PetscFunctionBegin;
3152: PetscTryMethod(pc, "PCFieldSplitSetGKBTol_C", (PC, PetscReal), (pc, tolerance));
3153: PetscFunctionReturn(PETSC_SUCCESS);
3154: }
3156: static PetscErrorCode PCFieldSplitSetGKBTol_FieldSplit(PC pc, PetscReal tolerance)
3157: {
3158: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3160: PetscFunctionBegin;
3161: jac->gkbtol = tolerance;
3162: PetscFunctionReturn(PETSC_SUCCESS);
3163: }
3165: /*@
3166: PCFieldSplitSetGKBMaxit - Sets the maximum number of iterations for the generalized Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
3168: Collective
3170: Input Parameters:
3171: + pc - the preconditioner context
3172: - maxit - the maximum number of iterations
3174: Options Database Key:
3175: . -pc_fieldsplit_gkb_maxit maxit - default is 100
3177: Level: intermediate
3179: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBNu()`
3180: @*/
3181: PetscErrorCode PCFieldSplitSetGKBMaxit(PC pc, PetscInt maxit)
3182: {
3183: PetscFunctionBegin;
3186: PetscTryMethod(pc, "PCFieldSplitSetGKBMaxit_C", (PC, PetscInt), (pc, maxit));
3187: PetscFunctionReturn(PETSC_SUCCESS);
3188: }
3190: static PetscErrorCode PCFieldSplitSetGKBMaxit_FieldSplit(PC pc, PetscInt maxit)
3191: {
3192: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3194: PetscFunctionBegin;
3195: jac->gkbmaxit = maxit;
3196: PetscFunctionReturn(PETSC_SUCCESS);
3197: }
3199: /*@
3200: PCFieldSplitSetGKBDelay - Sets the delay in the lower bound error estimate in the generalized Golub-Kahan bidiagonalization {cite}`arioli2013` in `PCFIELDSPLIT`
3201: preconditioner.
3203: Collective
3205: Input Parameters:
3206: + pc - the preconditioner context
3207: - delay - the delay window in the lower bound estimate
3209: Options Database Key:
3210: . -pc_fieldsplit_gkb_delay delay - default is 5
3212: Level: intermediate
3214: Notes:
3215: 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 $
3216: is expressed as a truncated sum. The error at iteration k can only be measured at iteration (k + `delay`), and thus the algorithm needs
3217: at least (`delay` + 1) iterations to stop.
3219: For more details on the generalized Golub-Kahan bidiagonalization method and its lower bound stopping criterion, please refer to {cite}`arioli2013`
3221: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBNu()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
3222: @*/
3223: PetscErrorCode PCFieldSplitSetGKBDelay(PC pc, PetscInt delay)
3224: {
3225: PetscFunctionBegin;
3228: PetscTryMethod(pc, "PCFieldSplitSetGKBDelay_C", (PC, PetscInt), (pc, delay));
3229: PetscFunctionReturn(PETSC_SUCCESS);
3230: }
3232: static PetscErrorCode PCFieldSplitSetGKBDelay_FieldSplit(PC pc, PetscInt delay)
3233: {
3234: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3236: PetscFunctionBegin;
3237: jac->gkbdelay = delay;
3238: PetscFunctionReturn(PETSC_SUCCESS);
3239: }
3241: /*@
3242: PCFieldSplitSetGKBNu - Sets the scalar value nu >= 0 in the transformation H = A00 + nu*A01*A01' of the (1,1) block in the
3243: Golub-Kahan bidiagonalization preconditioner {cite}`arioli2013` in `PCFIELDSPLIT`
3245: Collective
3247: Input Parameters:
3248: + pc - the preconditioner context
3249: - nu - the shift parameter
3251: Options Database Key:
3252: . -pc_fieldsplit_gkb_nu nu - default is 1
3254: Level: intermediate
3256: Notes:
3257: 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,
3258: 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
3259: necessary to find a good balance in between the convergence of the inner and outer loop.
3261: 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.
3263: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetGKBDelay()`, `PCFieldSplitSetGKBTol()`, `PCFieldSplitSetGKBMaxit()`
3264: @*/
3265: PetscErrorCode PCFieldSplitSetGKBNu(PC pc, PetscReal nu)
3266: {
3267: PetscFunctionBegin;
3270: PetscTryMethod(pc, "PCFieldSplitSetGKBNu_C", (PC, PetscReal), (pc, nu));
3271: PetscFunctionReturn(PETSC_SUCCESS);
3272: }
3274: static PetscErrorCode PCFieldSplitSetGKBNu_FieldSplit(PC pc, PetscReal nu)
3275: {
3276: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3278: PetscFunctionBegin;
3279: jac->gkbnu = nu;
3280: PetscFunctionReturn(PETSC_SUCCESS);
3281: }
3283: static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc, PCCompositeType type)
3284: {
3285: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3287: PetscFunctionBegin;
3288: jac->type = type;
3289: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", NULL));
3290: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", NULL));
3291: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", NULL));
3292: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", NULL));
3293: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", NULL));
3294: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", NULL));
3295: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", NULL));
3296: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", NULL));
3297: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", NULL));
3299: if (type == PC_COMPOSITE_SCHUR) {
3300: pc->ops->apply = PCApply_FieldSplit_Schur;
3301: pc->ops->applytranspose = PCApplyTranspose_FieldSplit_Schur;
3302: pc->ops->matapply = PCMatApply_FieldSplit_Schur;
3303: pc->ops->view = PCView_FieldSplit_Schur;
3304: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_Schur;
3306: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit_Schur));
3307: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurPre_C", PCFieldSplitSetSchurPre_FieldSplit));
3308: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSchurPre_C", PCFieldSplitGetSchurPre_FieldSplit));
3309: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurFactType_C", PCFieldSplitSetSchurFactType_FieldSplit));
3310: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetSchurScale_C", PCFieldSplitSetSchurScale_FieldSplit));
3311: } else if (type == PC_COMPOSITE_GKB) {
3312: pc->ops->apply = PCApply_FieldSplit_GKB;
3313: pc->ops->applytranspose = NULL;
3314: pc->ops->matapply = NULL;
3315: pc->ops->view = PCView_FieldSplit_GKB;
3316: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit_GKB;
3318: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3319: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBTol_C", PCFieldSplitSetGKBTol_FieldSplit));
3320: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBMaxit_C", PCFieldSplitSetGKBMaxit_FieldSplit));
3321: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBNu_C", PCFieldSplitSetGKBNu_FieldSplit));
3322: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetGKBDelay_C", PCFieldSplitSetGKBDelay_FieldSplit));
3323: } else {
3324: pc->ops->apply = PCApply_FieldSplit;
3325: pc->ops->applytranspose = PCApplyTranspose_FieldSplit;
3326: pc->ops->matapply = PCMatApply_FieldSplit;
3327: pc->ops->view = PCView_FieldSplit;
3328: pc->ops->setuponblocks = PCSetUpOnBlocks_FieldSplit;
3330: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitGetSubKSP_C", PCFieldSplitGetSubKSP_FieldSplit));
3331: }
3332: PetscFunctionReturn(PETSC_SUCCESS);
3333: }
3335: static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc, PetscInt bs)
3336: {
3337: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3339: PetscFunctionBegin;
3340: PetscCheck(bs >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Blocksize must be positive, you gave %" PetscInt_FMT, bs);
3341: 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);
3342: jac->bs = bs;
3343: PetscFunctionReturn(PETSC_SUCCESS);
3344: }
3346: static PetscErrorCode PCSetCoordinates_FieldSplit(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[])
3347: {
3348: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3349: PC_FieldSplitLink ilink_current = jac->head;
3350: IS is_owned;
3352: PetscFunctionBegin;
3353: jac->coordinates_set = PETSC_TRUE; // Internal flag
3354: PetscCall(MatGetOwnershipIS(pc->mat, &is_owned, NULL));
3356: while (ilink_current) {
3357: // For each IS, embed it to get local coords indces
3358: IS is_coords;
3359: PetscInt ndofs_block;
3360: const PetscInt *block_dofs_enumeration; // Numbering of the dofs relevant to the current block
3362: // Setting drop to true for safety. It should make no difference.
3363: PetscCall(ISEmbed(ilink_current->is, is_owned, PETSC_TRUE, &is_coords));
3364: PetscCall(ISGetLocalSize(is_coords, &ndofs_block));
3365: PetscCall(ISGetIndices(is_coords, &block_dofs_enumeration));
3367: // Allocate coordinates vector and set it directly
3368: PetscCall(PetscMalloc1(ndofs_block * dim, &ilink_current->coords));
3369: for (PetscInt dof = 0; dof < ndofs_block; ++dof) {
3370: for (PetscInt d = 0; d < dim; ++d) (ilink_current->coords)[dim * dof + d] = coords[dim * block_dofs_enumeration[dof] + d];
3371: }
3372: ilink_current->dim = dim;
3373: ilink_current->ndofs = ndofs_block;
3374: PetscCall(ISRestoreIndices(is_coords, &block_dofs_enumeration));
3375: PetscCall(ISDestroy(&is_coords));
3376: ilink_current = ilink_current->next;
3377: }
3378: PetscCall(ISDestroy(&is_owned));
3379: PetscFunctionReturn(PETSC_SUCCESS);
3380: }
3382: /*@
3383: PCFieldSplitSetType - Sets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3385: Collective
3387: Input Parameters:
3388: + pc - the preconditioner context
3389: - type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`,
3390: `PC_COMPOSITE_GKB`
3392: Options Database Key:
3393: . -pc_fieldsplit_type (multiplicative|additive|symmetric_multiplicative|special|schur) - Sets fieldsplit preconditioner type
3395: Level: intermediate
3397: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCCompositeType`, `PCCompositeGetType()`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3398: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`, `PCFieldSplitSetSchurFactType()`
3399: @*/
3400: PetscErrorCode PCFieldSplitSetType(PC pc, PCCompositeType type)
3401: {
3402: PetscFunctionBegin;
3404: PetscTryMethod(pc, "PCFieldSplitSetType_C", (PC, PCCompositeType), (pc, type));
3405: PetscFunctionReturn(PETSC_SUCCESS);
3406: }
3408: /*@
3409: PCFieldSplitGetType - Gets the type, `PCCompositeType`, of a `PCFIELDSPLIT`
3411: Not collective
3413: Input Parameter:
3414: . pc - the preconditioner context
3416: Output Parameter:
3417: . type - `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE` (default), `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3419: Level: intermediate
3421: .seealso: [](sec_block_matrices), `PC`, `PCCompositeSetType()`, `PCFIELDSPLIT`, `PCCompositeType`, `PC_COMPOSITE_ADDITIVE`, `PC_COMPOSITE_MULTIPLICATIVE`,
3422: `PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE`, `PC_COMPOSITE_SPECIAL`, `PC_COMPOSITE_SCHUR`
3423: @*/
3424: PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type)
3425: {
3426: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3428: PetscFunctionBegin;
3430: PetscAssertPointer(type, 2);
3431: *type = jac->type;
3432: PetscFunctionReturn(PETSC_SUCCESS);
3433: }
3435: /*@
3436: PCFieldSplitSetDMSplits - Flags whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3438: Logically Collective
3440: Input Parameters:
3441: + pc - the preconditioner context
3442: - flg - boolean indicating whether to use field splits defined by the `DM`
3444: Options Database Key:
3445: . -pc_fieldsplit_dm_splits (true|false) - use the field splits defined by the `DM`
3447: Level: intermediate
3449: Developer Note:
3450: The name should be `PCFieldSplitSetUseDMSplits()`, similar change to options database
3452: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3453: @*/
3454: PetscErrorCode PCFieldSplitSetDMSplits(PC pc, PetscBool flg)
3455: {
3456: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3457: PetscBool isfs;
3459: PetscFunctionBegin;
3462: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3463: if (isfs) jac->dm_splits = flg;
3464: PetscFunctionReturn(PETSC_SUCCESS);
3465: }
3467: /*@
3468: PCFieldSplitGetDMSplits - Returns flag indicating whether `DMCreateFieldDecomposition()` should be used to define the splits in a `PCFIELDSPLIT`, whenever possible.
3470: Logically Collective
3472: Input Parameter:
3473: . pc - the preconditioner context
3475: Output Parameter:
3476: . flg - boolean indicating whether to use field splits defined by the `DM`
3478: Level: intermediate
3480: Developer Note:
3481: The name should be `PCFieldSplitGetUseDMSplits()`
3483: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDMSplits()`, `DMCreateFieldDecomposition()`, `PCFieldSplitSetFields()`, `PCFieldSplitSetIS()`
3484: @*/
3485: PetscErrorCode PCFieldSplitGetDMSplits(PC pc, PetscBool *flg)
3486: {
3487: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3488: PetscBool isfs;
3490: PetscFunctionBegin;
3492: PetscAssertPointer(flg, 2);
3493: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &isfs));
3494: if (isfs) {
3495: if (flg) *flg = jac->dm_splits;
3496: }
3497: PetscFunctionReturn(PETSC_SUCCESS);
3498: }
3500: /*@
3501: PCFieldSplitGetDetectSaddlePoint - Returns flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3503: Logically Collective
3505: Input Parameter:
3506: . pc - the preconditioner context
3508: Output Parameter:
3509: . flg - boolean indicating whether to detect fields or not
3511: Level: intermediate
3513: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitSetDetectSaddlePoint()`
3514: @*/
3515: PetscErrorCode PCFieldSplitGetDetectSaddlePoint(PC pc, PetscBool *flg)
3516: {
3517: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3519: PetscFunctionBegin;
3520: *flg = jac->detect;
3521: PetscFunctionReturn(PETSC_SUCCESS);
3522: }
3524: /*@
3525: PCFieldSplitSetDetectSaddlePoint - Sets flag indicating whether `PCFIELDSPLIT` will attempt to automatically determine fields based on zero diagonal entries.
3527: Logically Collective
3529: Input Parameter:
3530: . pc - the preconditioner context
3532: Output Parameter:
3533: . flg - boolean indicating whether to detect fields or not
3535: Options Database Key:
3536: . -pc_fieldsplit_detect_saddle_point (true|false) - detect and use the saddle point
3538: Level: intermediate
3540: Note:
3541: Also sets the split type to `PC_COMPOSITE_SCHUR` (see `PCFieldSplitSetType()`) and the Schur preconditioner type to `PC_FIELDSPLIT_SCHUR_PRE_SELF` (see `PCFieldSplitSetSchurPre()`).
3543: .seealso: [](sec_block_matrices), `PC`, `PCFIELDSPLIT`, `PCFieldSplitGetDetectSaddlePoint()`, `PCFieldSplitSetType()`, `PCFieldSplitSetSchurPre()`, `PC_FIELDSPLIT_SCHUR_PRE_SELF`
3544: @*/
3545: PetscErrorCode PCFieldSplitSetDetectSaddlePoint(PC pc, PetscBool flg)
3546: {
3547: PC_FieldSplit *jac = (PC_FieldSplit *)pc->data;
3549: PetscFunctionBegin;
3550: jac->detect = flg;
3551: if (jac->detect) {
3552: PetscCall(PCFieldSplitSetType(pc, PC_COMPOSITE_SCHUR));
3553: PetscCall(PCFieldSplitSetSchurPre(pc, PC_FIELDSPLIT_SCHUR_PRE_SELF, NULL));
3554: }
3555: PetscFunctionReturn(PETSC_SUCCESS);
3556: }
3558: /*MC
3559: PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual
3560: collections of variables (that may overlap) called fields or splits. Each field often represents a different continuum variable
3561: represented on a grid, such as velocity, pressure, or temperature.
3562: In the literature these are sometimes called block preconditioners; but should not be confused with `PCBJACOBI`.
3563: See [the users manual section on "Solving Block Matrices"](sec_block_matrices) for more details.
3565: Options Database Keys:
3566: + -pc_fieldsplit_%d_fields a,b,... - indicates the fields to be used in the `%d`'th split
3567: . -pc_fieldsplit_default - automatically add any fields to additional splits that have not
3568: been supplied explicitly by `-pc_fieldsplit_%d_fields`
3569: . -pc_fieldsplit_block_size bs - size of block that defines fields (i.e. there are bs fields)
3570: when the matrix is not of `MatType` `MATNEST`
3571: . -pc_fieldsplit_type (additive|multiplicative|symmetric_multiplicative|schur|gkb) - type of relaxation or factorization splitting
3572: . -pc_fieldsplit_schur_precondition (self|selfp|user|a11|full) - default is `a11`; see `PCFieldSplitSetSchurPre()`
3573: . -pc_fieldsplit_schur_fact_type (diag|lower|upper|full) - set factorization type when using `-pc_fieldsplit_type schur`;
3574: see `PCFieldSplitSetSchurFactType()`
3575: . -pc_fieldsplit_dm_splits (true|false) (default is true) - Whether to use `DMCreateFieldDecomposition()` for splits
3576: - -pc_fieldsplit_detect_saddle_point (true|false) - automatically finds rows with zero diagonal and uses Schur complement with no preconditioner as the solver
3578: Options prefixes for inner solvers when using the Schur complement preconditioner are `-fieldsplit_0_` and `-fieldsplit_1_` .
3579: The options prefix for the inner solver when using the Golub-Kahan biadiagonalization preconditioner is `-fieldsplit_0_`
3580: For all other solvers they are `-fieldsplit_%d_` for the `%d`'th field; use `-fieldsplit_` for all fields.
3582: To set options on the solvers for all blocks, prepend `-fieldsplit_` to all the `PC`
3583: options database keys. For example, `-fieldsplit_pc_type ilu` `-fieldsplit_pc_factor_levels 1`.
3585: To set the options on the solvers separate for each block call `PCFieldSplitGetSubKSP()`
3586: and set the options directly on the resulting `KSP` object
3588: Level: intermediate
3590: Notes:
3591: Use `PCFieldSplitSetFields()` to set splits defined by "strided" entries or with a `MATNEST` and `PCFieldSplitSetIS()`
3592: to define a split by an arbitrary collection of entries.
3594: If no splits are set, the default is used. If a `DM` is associated with the `PC` and it supports
3595: `DMCreateFieldDecomposition()`, then that is used for the default. Otherwise if the matrix is not `MATNEST`, the splits are defined by entries strided by bs,
3596: beginning at 0 then 1, etc to bs-1. The block size can be set with `PCFieldSplitSetBlockSize()`,
3597: if this is not called the block size defaults to the blocksize of the second matrix passed
3598: to `KSPSetOperators()`/`PCSetOperators()`.
3600: For the Schur complement preconditioner if
3601: ```{math}
3602: J = \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{10} & A_{11} \end{array}\right]
3603: ```
3605: the preconditioner using `full` factorization is logically
3606: ```{math}
3607: \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]
3608: ```
3609: where the action of $\text{ksp}(A_{00})$ is applied using the `KSP` solver with prefix `-fieldsplit_0_`. $S$ is the Schur complement
3610: ```{math}
3611: S = A_{11} - A_{10} \text{ksp}(A_{00}) A_{01}
3612: ```
3613: 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`
3614: 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
3615: 0th index, the `KSP` associated with `-fieldsplit_0_`, and at its 1st index, the `KSP` corresponding to `-fieldsplit_1_`.
3616: By default, $A_{11}$ is used to construct a preconditioner for $S$, use `PCFieldSplitSetSchurPre()` for all the possible ways to construct the preconditioner for $S$.
3618: The factorization type is set using `-pc_fieldsplit_schur_fact_type <diag, lower, upper, full>`. `full` is shown above,
3619: `diag` gives
3620: ```{math}
3621: \left[\begin{array}{cc} \text{ksp}(A_{00}) & 0 \\ 0 & -\text{ksp}(S) \end{array}\right]
3622: ```
3623: 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
3624: can be turned off with `PCFieldSplitSetSchurScale()` or by command line `-pc_fieldsplit_schur_scale 1.0`. The `lower` factorization is the inverse of
3625: ```{math}
3626: \left[\begin{array}{cc} A_{00} & 0 \\ A_{10} & S \end{array}\right]
3627: ```
3628: where the inverses of $A_{00}$ and $S$ are applied using `KSP`s. The upper factorization is the inverse of
3629: ```{math}
3630: \left[\begin{array}{cc} A_{00} & A_{01} \\ 0 & S \end{array}\right]
3631: ```
3632: where again the inverses of $A_{00}$ and $S$ are applied using `KSP`s.
3634: If only one set of indices (one `IS`) is provided with `PCFieldSplitSetIS()` then the complement of that `IS`
3635: is used automatically for a second submatrix.
3637: The fieldsplit preconditioner cannot currently be used with the `MATBAIJ` or `MATSBAIJ` data formats if the blocksize is larger than 1.
3638: Generally it should be used with the `MATAIJ` or `MATNEST` `MatType`
3640: The forms of these preconditioners are closely related, if not identical, to forms derived as "Distributive Iterations", see,
3641: for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling {cite}`wesseling2009`.
3642: One can also use `PCFIELDSPLIT` inside a smoother resulting in "Distributive Smoothers".
3644: See "A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations" {cite}`elman2008tcp`.
3646: The Constrained Pressure Preconditioner (CPR) can be implemented using `PCCOMPOSITE` with `PCGALERKIN`. CPR first solves an $R A P$ subsystem, updates the
3647: residual on all variables (`PCCompositeSetType(pc,PC_COMPOSITE_MULTIPLICATIVE)`), and then applies a simple ILU like preconditioner on all the variables.
3649: The generalized Golub-Kahan bidiagonalization preconditioner (GKB) can be applied to symmetric $2 \times 2$ block matrices of the shape
3650: ```{math}
3651: \left[\begin{array}{cc} A_{00} & A_{01} \\ A_{01}' & 0 \end{array}\right]
3652: ```
3653: 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 $H = _{A00} + \nu*A_{01}*A_{01}'$.
3654: 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_`.
3656: Some `PCFIELDSPLIT` variants are called physics-based preconditioners, since the preconditioner takes into account the underlying physics of the
3657: problem. But this nomenclature is not well-defined.
3659: Developer Note:
3660: The Schur complement functionality of `PCFIELDSPLIT` should likely be factored into its own `PC` thus simplifying the implementation of the preconditioners and their
3661: user API.
3663: .seealso: [](sec_block_matrices), `PC`, `PCCreate()`, `PCSetType()`, `PCType`, `PCLSC`,
3664: `PCFieldSplitGetSubKSP()`, `PCFieldSplitSchurGetSubKSP()`, `PCFieldSplitSetFields()`,
3665: `PCFieldSplitSetType()`, `PCFieldSplitSetIS()`, `PCFieldSplitSetSchurPre()`, `PCFieldSplitSetSchurFactType()`,
3666: `MatSchurComplementSetAinvType()`, `PCFieldSplitSetSchurScale()`, `PCFieldSplitSetDetectSaddlePoint()`
3667: M*/
3669: PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc)
3670: {
3671: PC_FieldSplit *jac;
3673: PetscFunctionBegin;
3674: PetscCall(PetscNew(&jac));
3676: jac->bs = -1;
3677: jac->type = PC_COMPOSITE_MULTIPLICATIVE;
3678: jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */
3679: jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL;
3680: jac->schurscale = -1.0;
3681: jac->dm_splits = PETSC_TRUE;
3682: jac->gkbtol = 1e-5;
3683: jac->gkbdelay = 5;
3684: jac->gkbnu = 1;
3685: jac->gkbmaxit = 100;
3687: pc->data = (void *)jac;
3689: pc->ops->setup = PCSetUp_FieldSplit;
3690: pc->ops->reset = PCReset_FieldSplit;
3691: pc->ops->destroy = PCDestroy_FieldSplit;
3692: pc->ops->setfromoptions = PCSetFromOptions_FieldSplit;
3693: pc->ops->applyrichardson = NULL;
3695: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSchurGetSubKSP_C", PCFieldSplitSchurGetSubKSP_FieldSplit));
3696: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetFields_C", PCFieldSplitSetFields_FieldSplit));
3697: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetIS_C", PCFieldSplitSetIS_FieldSplit));
3698: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetType_C", PCFieldSplitSetType_FieldSplit));
3699: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitSetBlockSize_C", PCFieldSplitSetBlockSize_FieldSplit));
3700: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCFieldSplitRestrictIS_C", PCFieldSplitRestrictIS_FieldSplit));
3701: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", PCSetCoordinates_FieldSplit));
3703: /* Initialize function pointers */
3704: PetscCall(PCFieldSplitSetType(pc, jac->type));
3705: PetscFunctionReturn(PETSC_SUCCESS);
3706: }