Actual source code: fieldsplit.c
petsc-3.10.2 2018-10-09
3: #include <petsc/private/pcimpl.h>
4: #include <petsc/private/kspimpl.h> /* This is needed to provide the appropriate PETSC_EXTERN for KSP_Solve_FS ....*/
5: #include <petscdm.h>
7: const char *const PCFieldSplitSchurPreTypes[] = {"SELF","SELFP","A11","USER","FULL","PCFieldSplitSchurPreType","PC_FIELDSPLIT_SCHUR_PRE_",0};
8: const char *const PCFieldSplitSchurFactTypes[] = {"DIAG","LOWER","UPPER","FULL","PCFieldSplitSchurFactType","PC_FIELDSPLIT_SCHUR_FACT_",0};
10: 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;
12: typedef struct _PC_FieldSplitLink *PC_FieldSplitLink;
13: struct _PC_FieldSplitLink {
14: KSP ksp;
15: Vec x,y,z;
16: char *splitname;
17: PetscInt nfields;
18: PetscInt *fields,*fields_col;
19: VecScatter sctx;
20: IS is,is_col;
21: PC_FieldSplitLink next,previous;
22: PetscLogEvent event;
23: };
25: typedef struct {
26: PCCompositeType type;
27: PetscBool defaultsplit; /* Flag for a system with a set of 'k' scalar fields with the same layout (and bs = k) */
28: PetscBool splitdefined; /* Flag is set after the splits have been defined, to prevent more splits from being added */
29: PetscInt bs; /* Block size for IS and Mat structures */
30: PetscInt nsplits; /* Number of field divisions defined */
31: Vec *x,*y,w1,w2;
32: Mat *mat; /* The diagonal block for each split */
33: Mat *pmat; /* The preconditioning diagonal block for each split */
34: Mat *Afield; /* The rows of the matrix associated with each split */
35: PetscBool issetup;
37: /* Only used when Schur complement preconditioning is used */
38: Mat B; /* The (0,1) block */
39: Mat C; /* The (1,0) block */
40: Mat schur; /* The Schur complement S = A11 - A10 A00^{-1} A01, the KSP here, kspinner, is H_1 in [El08] */
41: Mat schurp; /* Assembled approximation to S built by MatSchurComplement to be used as a preconditioning matrix when solving with S */
42: Mat schur_user; /* User-provided preconditioning matrix for the Schur complement */
43: PCFieldSplitSchurPreType schurpre; /* Determines which preconditioning matrix is used for the Schur complement */
44: PCFieldSplitSchurFactType schurfactorization;
45: KSP kspschur; /* The solver for S */
46: KSP kspupper; /* The solver for A in the upper diagonal part of the factorization (H_2 in [El08]) */
47: PetscScalar schurscale; /* Scaling factor for the Schur complement solution with DIAG factorization */
49: PC_FieldSplitLink head;
50: PetscBool isrestrict; /* indicates PCFieldSplitRestrictIS() has been last called on this object, hack */
51: PetscBool suboptionsset; /* Indicates that the KSPSetFromOptions() has been called on the sub-KSPs */
52: PetscBool dm_splits; /* Whether to use DMCreateFieldDecomposition() whenever possible */
53: PetscBool diag_use_amat; /* Whether to extract diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */
54: PetscBool offdiag_use_amat; /* Whether to extract off-diagonal matrix blocks from Amat, rather than Pmat (weaker than -pc_use_amat) */
55: PetscBool detect; /* Whether to form 2-way split by finding zero diagonal entries */
56: } PC_FieldSplit;
58: /*
59: Notes:
60: there is no particular reason that pmat, x, and y are stored as arrays in PC_FieldSplit instead of
61: inside PC_FieldSplitLink, just historical. If you want to be able to add new fields after already using the
62: PC you could change this.
63: */
65: /* This helper is so that setting a user-provided preconditioning matrix is orthogonal to choosing to use it. This way the
66: * application-provided FormJacobian can provide this matrix without interfering with the user's (command-line) choices. */
67: static Mat FieldSplitSchurPre(PC_FieldSplit *jac)
68: {
69: switch (jac->schurpre) {
70: case PC_FIELDSPLIT_SCHUR_PRE_SELF: return jac->schur;
71: case PC_FIELDSPLIT_SCHUR_PRE_SELFP: return jac->schurp;
72: case PC_FIELDSPLIT_SCHUR_PRE_A11: return jac->pmat[1];
73: case PC_FIELDSPLIT_SCHUR_PRE_FULL: /* We calculate this and store it in schur_user */
74: case PC_FIELDSPLIT_SCHUR_PRE_USER: /* Use a user-provided matrix if it is given, otherwise diagonal block */
75: default:
76: return jac->schur_user ? jac->schur_user : jac->pmat[1];
77: }
78: }
81: #include <petscdraw.h>
82: static PetscErrorCode PCView_FieldSplit(PC pc,PetscViewer viewer)
83: {
84: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
85: PetscErrorCode ierr;
86: PetscBool iascii,isdraw;
87: PetscInt i,j;
88: PC_FieldSplitLink ilink = jac->head;
91: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
92: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
93: if (iascii) {
94: if (jac->bs > 0) {
95: PetscViewerASCIIPrintf(viewer," FieldSplit with %s composition: total splits = %D, blocksize = %D\n",PCCompositeTypes[jac->type],jac->nsplits,jac->bs);
96: } else {
97: PetscViewerASCIIPrintf(viewer," FieldSplit with %s composition: total splits = %D\n",PCCompositeTypes[jac->type],jac->nsplits);
98: }
99: if (pc->useAmat) {
100: PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for blocks\n");
101: }
102: if (jac->diag_use_amat) {
103: PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for diagonal blocks\n");
104: }
105: if (jac->offdiag_use_amat) {
106: PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for off-diagonal blocks\n");
107: }
108: PetscViewerASCIIPrintf(viewer," Solver info for each split is in the following KSP objects:\n");
109: for (i=0; i<jac->nsplits; i++) {
110: if (ilink->fields) {
111: PetscViewerASCIIPrintf(viewer,"Split number %D Fields ",i);
112: PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);
113: for (j=0; j<ilink->nfields; j++) {
114: if (j > 0) {
115: PetscViewerASCIIPrintf(viewer,",");
116: }
117: PetscViewerASCIIPrintf(viewer," %D",ilink->fields[j]);
118: }
119: PetscViewerASCIIPrintf(viewer,"\n");
120: PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);
121: } else {
122: PetscViewerASCIIPrintf(viewer,"Split number %D Defined by IS\n",i);
123: }
124: KSPView(ilink->ksp,viewer);
125: ilink = ilink->next;
126: }
127: }
129: if (isdraw) {
130: PetscDraw draw;
131: PetscReal x,y,w,wd;
133: PetscViewerDrawGetDraw(viewer,0,&draw);
134: PetscDrawGetCurrentPoint(draw,&x,&y);
135: w = 2*PetscMin(1.0 - x,x);
136: wd = w/(jac->nsplits + 1);
137: x = x - wd*(jac->nsplits-1)/2.0;
138: for (i=0; i<jac->nsplits; i++) {
139: PetscDrawPushCurrentPoint(draw,x,y);
140: KSPView(ilink->ksp,viewer);
141: PetscDrawPopCurrentPoint(draw);
142: x += wd;
143: ilink = ilink->next;
144: }
145: }
146: return(0);
147: }
149: static PetscErrorCode PCView_FieldSplit_Schur(PC pc,PetscViewer viewer)
150: {
151: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
152: PetscErrorCode ierr;
153: PetscBool iascii,isdraw;
154: PetscInt i,j;
155: PC_FieldSplitLink ilink = jac->head;
156: MatSchurComplementAinvType atype;
159: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
160: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
161: if (iascii) {
162: if (jac->bs > 0) {
163: PetscViewerASCIIPrintf(viewer," FieldSplit with Schur preconditioner, blocksize = %D, factorization %s\n",jac->bs,PCFieldSplitSchurFactTypes[jac->schurfactorization]);
164: } else {
165: PetscViewerASCIIPrintf(viewer," FieldSplit with Schur preconditioner, factorization %s\n",PCFieldSplitSchurFactTypes[jac->schurfactorization]);
166: }
167: if (pc->useAmat) {
168: PetscViewerASCIIPrintf(viewer," using Amat (not Pmat) as operator for blocks\n");
169: }
170: switch (jac->schurpre) {
171: case PC_FIELDSPLIT_SCHUR_PRE_SELF:
172: PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from S itself\n");
173: break;
174: case PC_FIELDSPLIT_SCHUR_PRE_SELFP:
175: MatSchurComplementGetAinvType(jac->schur,&atype);
176: PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from Sp, an assembled approximation to S, which uses A00's %sdiagonal's inverse\n",atype == MAT_SCHUR_COMPLEMENT_AINV_DIAG ? "" : (atype == MAT_SCHUR_COMPLEMENT_AINV_BLOCK_DIAG ? "block " : "lumped "));break;
177: case PC_FIELDSPLIT_SCHUR_PRE_A11:
178: PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from A11\n");
179: break;
180: case PC_FIELDSPLIT_SCHUR_PRE_FULL:
181: PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from the exact Schur complement\n");
182: break;
183: case PC_FIELDSPLIT_SCHUR_PRE_USER:
184: if (jac->schur_user) {
185: PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from user provided matrix\n");
186: } else {
187: PetscViewerASCIIPrintf(viewer," Preconditioner for the Schur complement formed from A11\n");
188: }
189: break;
190: default:
191: SETERRQ1(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Invalid Schur preconditioning type: %d", jac->schurpre);
192: }
193: PetscViewerASCIIPrintf(viewer," Split info:\n");
194: PetscViewerASCIIPushTab(viewer);
195: for (i=0; i<jac->nsplits; i++) {
196: if (ilink->fields) {
197: PetscViewerASCIIPrintf(viewer,"Split number %D Fields ",i);
198: PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);
199: for (j=0; j<ilink->nfields; j++) {
200: if (j > 0) {
201: PetscViewerASCIIPrintf(viewer,",");
202: }
203: PetscViewerASCIIPrintf(viewer," %D",ilink->fields[j]);
204: }
205: PetscViewerASCIIPrintf(viewer,"\n");
206: PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);
207: } else {
208: PetscViewerASCIIPrintf(viewer,"Split number %D Defined by IS\n",i);
209: }
210: ilink = ilink->next;
211: }
212: PetscViewerASCIIPrintf(viewer,"KSP solver for A00 block\n");
213: PetscViewerASCIIPushTab(viewer);
214: if (jac->head) {
215: KSPView(jac->head->ksp,viewer);
216: } else {PetscViewerASCIIPrintf(viewer," not yet available\n");}
217: PetscViewerASCIIPopTab(viewer);
218: if (jac->head && jac->kspupper != jac->head->ksp) {
219: PetscViewerASCIIPrintf(viewer,"KSP solver for upper A00 in upper triangular factor \n");
220: PetscViewerASCIIPushTab(viewer);
221: if (jac->kspupper) {KSPView(jac->kspupper,viewer);}
222: else {PetscViewerASCIIPrintf(viewer," not yet available\n");}
223: PetscViewerASCIIPopTab(viewer);
224: }
225: PetscViewerASCIIPrintf(viewer,"KSP solver for S = A11 - A10 inv(A00) A01 \n");
226: PetscViewerASCIIPushTab(viewer);
227: if (jac->kspschur) {
228: KSPView(jac->kspschur,viewer);
229: } else {
230: PetscViewerASCIIPrintf(viewer," not yet available\n");
231: }
232: PetscViewerASCIIPopTab(viewer);
233: PetscViewerASCIIPopTab(viewer);
234: } else if (isdraw && jac->head) {
235: PetscDraw draw;
236: PetscReal x,y,w,wd,h;
237: PetscInt cnt = 2;
238: char str[32];
240: PetscViewerDrawGetDraw(viewer,0,&draw);
241: PetscDrawGetCurrentPoint(draw,&x,&y);
242: if (jac->kspupper != jac->head->ksp) cnt++;
243: w = 2*PetscMin(1.0 - x,x);
244: wd = w/(cnt + 1);
246: PetscSNPrintf(str,32,"Schur fact. %s",PCFieldSplitSchurFactTypes[jac->schurfactorization]);
247: PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);
248: y -= h;
249: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_USER && !jac->schur_user) {
250: PetscSNPrintf(str,32,"Prec. for Schur from %s",PCFieldSplitSchurPreTypes[PC_FIELDSPLIT_SCHUR_PRE_A11]);
251: } else {
252: PetscSNPrintf(str,32,"Prec. for Schur from %s",PCFieldSplitSchurPreTypes[jac->schurpre]);
253: }
254: PetscDrawStringBoxed(draw,x+wd*(cnt-1)/2.0,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);
255: y -= h;
256: x = x - wd*(cnt-1)/2.0;
258: PetscDrawPushCurrentPoint(draw,x,y);
259: KSPView(jac->head->ksp,viewer);
260: PetscDrawPopCurrentPoint(draw);
261: if (jac->kspupper != jac->head->ksp) {
262: x += wd;
263: PetscDrawPushCurrentPoint(draw,x,y);
264: KSPView(jac->kspupper,viewer);
265: PetscDrawPopCurrentPoint(draw);
266: }
267: x += wd;
268: PetscDrawPushCurrentPoint(draw,x,y);
269: KSPView(jac->kspschur,viewer);
270: PetscDrawPopCurrentPoint(draw);
271: }
272: return(0);
273: }
275: /* Precondition: jac->bs is set to a meaningful value */
276: static PetscErrorCode PCFieldSplitSetRuntimeSplits_Private(PC pc)
277: {
279: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
280: PetscInt i,nfields,*ifields,nfields_col,*ifields_col;
281: PetscBool flg,flg_col;
282: char optionname[128],splitname[8],optionname_col[128];
285: PetscMalloc1(jac->bs,&ifields);
286: PetscMalloc1(jac->bs,&ifields_col);
287: for (i=0,flg=PETSC_TRUE;; i++) {
288: PetscSNPrintf(splitname,sizeof(splitname),"%D",i);
289: PetscSNPrintf(optionname,sizeof(optionname),"-pc_fieldsplit_%D_fields",i);
290: PetscSNPrintf(optionname_col,sizeof(optionname_col),"-pc_fieldsplit_%D_fields_col",i);
291: nfields = jac->bs;
292: nfields_col = jac->bs;
293: PetscOptionsGetIntArray(((PetscObject)pc)->options,((PetscObject)pc)->prefix,optionname,ifields,&nfields,&flg);
294: PetscOptionsGetIntArray(((PetscObject)pc)->options,((PetscObject)pc)->prefix,optionname_col,ifields_col,&nfields_col,&flg_col);
295: if (!flg) break;
296: else if (flg && !flg_col) {
297: if (!nfields) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot list zero fields");
298: PCFieldSplitSetFields(pc,splitname,nfields,ifields,ifields);
299: } else {
300: if (!nfields || !nfields_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Cannot list zero fields");
301: if (nfields != nfields_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Number of row and column fields must match");
302: PCFieldSplitSetFields(pc,splitname,nfields,ifields,ifields_col);
303: }
304: }
305: if (i > 0) {
306: /* Makes command-line setting of splits take precedence over setting them in code.
307: Otherwise subsequent calls to PCFieldSplitSetIS() or PCFieldSplitSetFields() would
308: create new splits, which would probably not be what the user wanted. */
309: jac->splitdefined = PETSC_TRUE;
310: }
311: PetscFree(ifields);
312: PetscFree(ifields_col);
313: return(0);
314: }
316: static PetscErrorCode PCFieldSplitSetDefaults(PC pc)
317: {
318: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
319: PetscErrorCode ierr;
320: PC_FieldSplitLink ilink = jac->head;
321: PetscBool fieldsplit_default = PETSC_FALSE,coupling = PETSC_FALSE;
322: PetscInt i;
325: /*
326: Kinda messy, but at least this now uses DMCreateFieldDecomposition().
327: Should probably be rewritten.
328: */
329: if (!ilink) {
330: PetscOptionsGetBool(((PetscObject)pc)->options,((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_coupling",&coupling,NULL);
331: if (pc->dm && jac->dm_splits && !jac->detect && !coupling) {
332: PetscInt numFields, f, i, j;
333: char **fieldNames;
334: IS *fields;
335: DM *dms;
336: DM subdm[128];
337: PetscBool flg;
339: DMCreateFieldDecomposition(pc->dm, &numFields, &fieldNames, &fields, &dms);
340: /* Allow the user to prescribe the splits */
341: for (i = 0, flg = PETSC_TRUE;; i++) {
342: PetscInt ifields[128];
343: IS compField;
344: char optionname[128], splitname[8];
345: PetscInt nfields = numFields;
347: PetscSNPrintf(optionname, sizeof(optionname), "-pc_fieldsplit_%D_fields", i);
348: PetscOptionsGetIntArray(((PetscObject)pc)->options,((PetscObject)pc)->prefix, optionname, ifields, &nfields, &flg);
349: if (!flg) break;
350: if (numFields > 128) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot currently support %d > 128 fields", numFields);
351: DMCreateSubDM(pc->dm, nfields, ifields, &compField, &subdm[i]);
352: if (nfields == 1) {
353: PCFieldSplitSetIS(pc, fieldNames[ifields[0]], compField);
354: } else {
355: PetscSNPrintf(splitname, sizeof(splitname), "%D", i);
356: PCFieldSplitSetIS(pc, splitname, compField);
357: }
358: ISDestroy(&compField);
359: for (j = 0; j < nfields; ++j) {
360: f = ifields[j];
361: PetscFree(fieldNames[f]);
362: ISDestroy(&fields[f]);
363: }
364: }
365: if (i == 0) {
366: for (f = 0; f < numFields; ++f) {
367: PCFieldSplitSetIS(pc, fieldNames[f], fields[f]);
368: PetscFree(fieldNames[f]);
369: ISDestroy(&fields[f]);
370: }
371: } else {
372: for (j=0; j<numFields; j++) {
373: DMDestroy(dms+j);
374: }
375: PetscFree(dms);
376: PetscMalloc1(i, &dms);
377: for (j = 0; j < i; ++j) dms[j] = subdm[j];
378: }
379: PetscFree(fieldNames);
380: PetscFree(fields);
381: if (dms) {
382: PetscInfo(pc, "Setting up physics based fieldsplit preconditioner using the embedded DM\n");
383: for (ilink = jac->head, i = 0; ilink; ilink = ilink->next, ++i) {
384: const char *prefix;
385: PetscObjectGetOptionsPrefix((PetscObject)(ilink->ksp),&prefix);
386: PetscObjectSetOptionsPrefix((PetscObject)(dms[i]), prefix);
387: KSPSetDM(ilink->ksp, dms[i]);
388: KSPSetDMActive(ilink->ksp, PETSC_FALSE);
389: PetscObjectIncrementTabLevel((PetscObject)dms[i],(PetscObject)ilink->ksp,0);
390: DMDestroy(&dms[i]);
391: }
392: PetscFree(dms);
393: }
394: } else {
395: if (jac->bs <= 0) {
396: if (pc->pmat) {
397: MatGetBlockSize(pc->pmat,&jac->bs);
398: } else jac->bs = 1;
399: }
401: if (jac->detect) {
402: IS zerodiags,rest;
403: PetscInt nmin,nmax;
405: MatGetOwnershipRange(pc->mat,&nmin,&nmax);
406: MatFindZeroDiagonals(pc->mat,&zerodiags);
407: ISComplement(zerodiags,nmin,nmax,&rest);
408: PCFieldSplitSetIS(pc,"0",rest);
409: PCFieldSplitSetIS(pc,"1",zerodiags);
410: ISDestroy(&zerodiags);
411: ISDestroy(&rest);
412: } else if (coupling) {
413: IS coupling,rest;
414: PetscInt nmin,nmax;
416: MatGetOwnershipRange(pc->mat,&nmin,&nmax);
417: MatFindOffBlockDiagonalEntries(pc->mat,&coupling);
418: ISCreateStride(PetscObjectComm((PetscObject)pc->mat),nmax-nmin,nmin,1,&rest);
419: ISSetIdentity(rest);
420: PCFieldSplitSetIS(pc,"0",rest);
421: PCFieldSplitSetIS(pc,"1",coupling);
422: ISDestroy(&coupling);
423: ISDestroy(&rest);
424: } else {
425: PetscOptionsGetBool(((PetscObject)pc)->options,((PetscObject)pc)->prefix,"-pc_fieldsplit_default",&fieldsplit_default,NULL);
426: if (!fieldsplit_default) {
427: /* Allow user to set fields from command line, if bs was known at the time of PCSetFromOptions_FieldSplit()
428: then it is set there. This is not ideal because we should only have options set in XXSetFromOptions(). */
429: PCFieldSplitSetRuntimeSplits_Private(pc);
430: if (jac->splitdefined) {PetscInfo(pc,"Splits defined using the options database\n");}
431: }
432: if ((fieldsplit_default || !jac->splitdefined) && !jac->isrestrict) {
433: PetscInfo(pc,"Using default splitting of fields\n");
434: for (i=0; i<jac->bs; i++) {
435: char splitname[8];
436: PetscSNPrintf(splitname,sizeof(splitname),"%D",i);
437: PCFieldSplitSetFields(pc,splitname,1,&i,&i);
438: }
439: jac->defaultsplit = PETSC_TRUE;
440: }
441: }
442: }
443: } else if (jac->nsplits == 1) {
444: if (ilink->is) {
445: IS is2;
446: PetscInt nmin,nmax;
448: MatGetOwnershipRange(pc->mat,&nmin,&nmax);
449: ISComplement(ilink->is,nmin,nmax,&is2);
450: PCFieldSplitSetIS(pc,"1",is2);
451: ISDestroy(&is2);
452: } else SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Must provide at least two sets of fields to PCFieldSplit()");
453: }
455: if (jac->nsplits < 2) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_PLIB,"Unhandled case, must have at least two fields, not %d", jac->nsplits);
456: return(0);
457: }
459: PETSC_EXTERN PetscErrorCode PetscOptionsFindPairPrefix_Private(PetscOptions,const char pre[], const char name[],const char *value[],PetscBool *flg);
461: static PetscErrorCode PCSetUp_FieldSplit(PC pc)
462: {
463: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
464: PetscErrorCode ierr;
465: PC_FieldSplitLink ilink;
466: PetscInt i,nsplit;
467: PetscBool sorted, sorted_col;
470: PCFieldSplitSetDefaults(pc);
471: nsplit = jac->nsplits;
472: ilink = jac->head;
474: /* get the matrices for each split */
475: if (!jac->issetup) {
476: PetscInt rstart,rend,nslots,bs;
478: jac->issetup = PETSC_TRUE;
480: /* This is done here instead of in PCFieldSplitSetFields() because may not have matrix at that point */
481: if (jac->defaultsplit || !ilink->is) {
482: if (jac->bs <= 0) jac->bs = nsplit;
483: }
484: bs = jac->bs;
485: MatGetOwnershipRange(pc->pmat,&rstart,&rend);
486: nslots = (rend - rstart)/bs;
487: for (i=0; i<nsplit; i++) {
488: if (jac->defaultsplit) {
489: ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+i,nsplit,&ilink->is);
490: ISDuplicate(ilink->is,&ilink->is_col);
491: } else if (!ilink->is) {
492: if (ilink->nfields > 1) {
493: PetscInt *ii,*jj,j,k,nfields = ilink->nfields,*fields = ilink->fields,*fields_col = ilink->fields_col;
494: PetscMalloc1(ilink->nfields*nslots,&ii);
495: PetscMalloc1(ilink->nfields*nslots,&jj);
496: for (j=0; j<nslots; j++) {
497: for (k=0; k<nfields; k++) {
498: ii[nfields*j + k] = rstart + bs*j + fields[k];
499: jj[nfields*j + k] = rstart + bs*j + fields_col[k];
500: }
501: }
502: ISCreateGeneral(PetscObjectComm((PetscObject)pc),nslots*nfields,ii,PETSC_OWN_POINTER,&ilink->is);
503: ISCreateGeneral(PetscObjectComm((PetscObject)pc),nslots*nfields,jj,PETSC_OWN_POINTER,&ilink->is_col);
504: ISSetBlockSize(ilink->is, nfields);
505: ISSetBlockSize(ilink->is_col, nfields);
506: } else {
507: ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+ilink->fields[0],bs,&ilink->is);
508: ISCreateStride(PetscObjectComm((PetscObject)pc),nslots,rstart+ilink->fields_col[0],bs,&ilink->is_col);
509: }
510: }
511: ISSorted(ilink->is,&sorted);
512: if (ilink->is_col) { ISSorted(ilink->is_col,&sorted_col); }
513: if (!sorted || !sorted_col) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_USER,"Fields must be sorted when creating split");
514: ilink = ilink->next;
515: }
516: }
518: ilink = jac->head;
519: if (!jac->pmat) {
520: Vec xtmp;
522: MatCreateVecs(pc->pmat,&xtmp,NULL);
523: PetscMalloc1(nsplit,&jac->pmat);
524: PetscMalloc2(nsplit,&jac->x,nsplit,&jac->y);
525: for (i=0; i<nsplit; i++) {
526: MatNullSpace sp;
528: /* Check for preconditioning matrix attached to IS */
529: PetscObjectQuery((PetscObject) ilink->is, "pmat", (PetscObject*) &jac->pmat[i]);
530: if (jac->pmat[i]) {
531: PetscObjectReference((PetscObject) jac->pmat[i]);
532: if (jac->type == PC_COMPOSITE_SCHUR) {
533: jac->schur_user = jac->pmat[i];
535: PetscObjectReference((PetscObject) jac->schur_user);
536: }
537: } else {
538: const char *prefix;
539: MatCreateSubMatrix(pc->pmat,ilink->is,ilink->is_col,MAT_INITIAL_MATRIX,&jac->pmat[i]);
540: KSPGetOptionsPrefix(ilink->ksp,&prefix);
541: MatSetOptionsPrefix(jac->pmat[i],prefix);
542: MatViewFromOptions(jac->pmat[i],NULL,"-mat_view");
543: }
544: /* create work vectors for each split */
545: MatCreateVecs(jac->pmat[i],&jac->x[i],&jac->y[i]);
546: ilink->x = jac->x[i]; ilink->y = jac->y[i]; ilink->z = NULL;
547: /* compute scatter contexts needed by multiplicative versions and non-default splits */
548: VecScatterCreate(xtmp,ilink->is,jac->x[i],NULL,&ilink->sctx);
549: PetscObjectQuery((PetscObject) ilink->is, "nearnullspace", (PetscObject*) &sp);
550: if (sp) {
551: MatSetNearNullSpace(jac->pmat[i], sp);
552: }
553: ilink = ilink->next;
554: }
555: VecDestroy(&xtmp);
556: } else {
557: MatReuse scall;
558: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
559: for (i=0; i<nsplit; i++) {
560: MatDestroy(&jac->pmat[i]);
561: }
562: scall = MAT_INITIAL_MATRIX;
563: } else scall = MAT_REUSE_MATRIX;
565: for (i=0; i<nsplit; i++) {
566: Mat pmat;
568: /* Check for preconditioning matrix attached to IS */
569: PetscObjectQuery((PetscObject) ilink->is, "pmat", (PetscObject*) &pmat);
570: if (!pmat) {
571: MatCreateSubMatrix(pc->pmat,ilink->is,ilink->is_col,scall,&jac->pmat[i]);
572: }
573: ilink = ilink->next;
574: }
575: }
576: if (jac->diag_use_amat) {
577: ilink = jac->head;
578: if (!jac->mat) {
579: PetscMalloc1(nsplit,&jac->mat);
580: for (i=0; i<nsplit; i++) {
581: MatCreateSubMatrix(pc->mat,ilink->is,ilink->is_col,MAT_INITIAL_MATRIX,&jac->mat[i]);
582: ilink = ilink->next;
583: }
584: } else {
585: MatReuse scall;
586: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
587: for (i=0; i<nsplit; i++) {
588: MatDestroy(&jac->mat[i]);
589: }
590: scall = MAT_INITIAL_MATRIX;
591: } else scall = MAT_REUSE_MATRIX;
593: for (i=0; i<nsplit; i++) {
594: if (jac->mat[i]) {MatCreateSubMatrix(pc->mat,ilink->is,ilink->is_col,scall,&jac->mat[i]);}
595: ilink = ilink->next;
596: }
597: }
598: } else {
599: jac->mat = jac->pmat;
600: }
602: /* Check for null space attached to IS */
603: ilink = jac->head;
604: for (i=0; i<nsplit; i++) {
605: MatNullSpace sp;
607: PetscObjectQuery((PetscObject) ilink->is, "nullspace", (PetscObject*) &sp);
608: if (sp) {
609: MatSetNullSpace(jac->mat[i], sp);
610: }
611: ilink = ilink->next;
612: }
614: if (jac->type != PC_COMPOSITE_ADDITIVE && jac->type != PC_COMPOSITE_SCHUR) {
615: /* extract the rows of the matrix associated with each field: used for efficient computation of residual inside algorithm */
616: /* FIXME: Can/should we reuse jac->mat whenever (jac->diag_use_amat) is true? */
617: ilink = jac->head;
618: if (nsplit == 2 && jac->type == PC_COMPOSITE_MULTIPLICATIVE) {
619: /* 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 */
620: if (!jac->Afield) {
621: PetscCalloc1(nsplit,&jac->Afield);
622: if (jac->offdiag_use_amat) {
623: MatCreateSubMatrix(pc->mat,ilink->next->is,ilink->is,MAT_INITIAL_MATRIX,&jac->Afield[1]);
624: } else {
625: MatCreateSubMatrix(pc->pmat,ilink->next->is,ilink->is,MAT_INITIAL_MATRIX,&jac->Afield[1]);
626: }
627: } else {
628: MatReuse scall;
629: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
630: for (i=0; i<nsplit; i++) {
631: MatDestroy(&jac->Afield[1]);
632: }
633: scall = MAT_INITIAL_MATRIX;
634: } else scall = MAT_REUSE_MATRIX;
636: if (jac->offdiag_use_amat) {
637: MatCreateSubMatrix(pc->mat,ilink->next->is,ilink->is,scall,&jac->Afield[1]);
638: } else {
639: MatCreateSubMatrix(pc->pmat,ilink->next->is,ilink->is,scall,&jac->Afield[1]);
640: }
641: }
642: } else {
643: if (!jac->Afield) {
644: PetscMalloc1(nsplit,&jac->Afield);
645: for (i=0; i<nsplit; i++) {
646: if (jac->offdiag_use_amat) {
647: MatCreateSubMatrix(pc->mat,ilink->is,NULL,MAT_INITIAL_MATRIX,&jac->Afield[i]);
648: } else {
649: MatCreateSubMatrix(pc->pmat,ilink->is,NULL,MAT_INITIAL_MATRIX,&jac->Afield[i]);
650: }
651: ilink = ilink->next;
652: }
653: } else {
654: MatReuse scall;
655: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
656: for (i=0; i<nsplit; i++) {
657: MatDestroy(&jac->Afield[i]);
658: }
659: scall = MAT_INITIAL_MATRIX;
660: } else scall = MAT_REUSE_MATRIX;
662: for (i=0; i<nsplit; i++) {
663: if (jac->offdiag_use_amat) {
664: MatCreateSubMatrix(pc->mat,ilink->is,NULL,scall,&jac->Afield[i]);
665: } else {
666: MatCreateSubMatrix(pc->pmat,ilink->is,NULL,scall,&jac->Afield[i]);
667: }
668: ilink = ilink->next;
669: }
670: }
671: }
672: }
674: if (jac->type == PC_COMPOSITE_SCHUR) {
675: IS ccis;
676: PetscBool isspd;
677: PetscInt rstart,rend;
678: char lscname[256];
679: PetscObject LSC_L;
681: if (nsplit != 2) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_INCOMP,"To use Schur complement preconditioner you must have exactly 2 fields");
683: /* If pc->mat is SPD, don't scale by -1 the Schur complement */
684: if (jac->schurscale == (PetscScalar)-1.0) {
685: MatGetOption(pc->pmat,MAT_SPD,&isspd);
686: jac->schurscale = (isspd == PETSC_TRUE) ? 1.0 : -1.0;
687: }
689: /* When extracting off-diagonal submatrices, we take complements from this range */
690: MatGetOwnershipRangeColumn(pc->mat,&rstart,&rend);
692: /* need to handle case when one is resetting up the preconditioner */
693: if (jac->schur) {
694: KSP kspA = jac->head->ksp, kspInner = NULL, kspUpper = jac->kspupper;
696: MatSchurComplementGetKSP(jac->schur, &kspInner);
697: ilink = jac->head;
698: ISComplement(ilink->is_col,rstart,rend,&ccis);
699: if (jac->offdiag_use_amat) {
700: MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->B);
701: } else {
702: MatCreateSubMatrix(pc->pmat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->B);
703: }
704: ISDestroy(&ccis);
705: ilink = ilink->next;
706: ISComplement(ilink->is_col,rstart,rend,&ccis);
707: if (jac->offdiag_use_amat) {
708: MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->C);
709: } else {
710: MatCreateSubMatrix(pc->pmat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->C);
711: }
712: ISDestroy(&ccis);
713: MatSchurComplementUpdateSubMatrices(jac->schur,jac->mat[0],jac->pmat[0],jac->B,jac->C,jac->mat[1]);
714: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) {
715: MatDestroy(&jac->schurp);
716: MatSchurComplementGetPmat(jac->schur,MAT_INITIAL_MATRIX,&jac->schurp);
717: }
718: if (kspA != kspInner) {
719: KSPSetOperators(kspA,jac->mat[0],jac->pmat[0]);
720: }
721: if (kspUpper != kspA) {
722: KSPSetOperators(kspUpper,jac->mat[0],jac->pmat[0]);
723: }
724: KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac));
725: } else {
726: const char *Dprefix;
727: char schurprefix[256], schurmatprefix[256];
728: char schurtestoption[256];
729: MatNullSpace sp;
730: PetscBool flg;
731: KSP kspt;
733: /* extract the A01 and A10 matrices */
734: ilink = jac->head;
735: ISComplement(ilink->is_col,rstart,rend,&ccis);
736: if (jac->offdiag_use_amat) {
737: MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->B);
738: } else {
739: MatCreateSubMatrix(pc->pmat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->B);
740: }
741: ISDestroy(&ccis);
742: ilink = ilink->next;
743: ISComplement(ilink->is_col,rstart,rend,&ccis);
744: if (jac->offdiag_use_amat) {
745: MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->C);
746: } else {
747: MatCreateSubMatrix(pc->pmat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->C);
748: }
749: ISDestroy(&ccis);
751: /* Use mat[0] (diagonal block of Amat) preconditioned by pmat[0] to define Schur complement */
752: MatCreate(((PetscObject)jac->mat[0])->comm,&jac->schur);
753: MatSetType(jac->schur,MATSCHURCOMPLEMENT);
754: MatSchurComplementSetSubMatrices(jac->schur,jac->mat[0],jac->pmat[0],jac->B,jac->C,jac->mat[1]);
755: PetscSNPrintf(schurmatprefix, sizeof(schurmatprefix), "%sfieldsplit_%s_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);
756: MatSetOptionsPrefix(jac->schur,schurmatprefix);
757: MatSchurComplementGetKSP(jac->schur,&kspt);
758: KSPSetOptionsPrefix(kspt,schurmatprefix);
760: /* Note: this is not true in general */
761: MatGetNullSpace(jac->mat[1], &sp);
762: if (sp) {
763: MatSetNullSpace(jac->schur, sp);
764: }
766: PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_inner_", ilink->splitname);
767: PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options,((PetscObject)pc)->prefix, schurtestoption, NULL, &flg);
768: if (flg) {
769: DM dmInner;
770: KSP kspInner;
771: PC pcInner;
773: MatSchurComplementGetKSP(jac->schur, &kspInner);
774: KSPReset(kspInner);
775: KSPSetOperators(kspInner,jac->mat[0],jac->pmat[0]);
776: PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_inner_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);
777: /* Indent this deeper to emphasize the "inner" nature of this solver. */
778: PetscObjectIncrementTabLevel((PetscObject)kspInner, (PetscObject) pc, 2);
779: PetscObjectIncrementTabLevel((PetscObject)kspInner->pc, (PetscObject) pc, 2);
780: KSPSetOptionsPrefix(kspInner, schurprefix);
782: /* Set DM for new solver */
783: KSPGetDM(jac->head->ksp, &dmInner);
784: KSPSetDM(kspInner, dmInner);
785: KSPSetDMActive(kspInner, PETSC_FALSE);
787: /* Defaults to PCKSP as preconditioner */
788: KSPGetPC(kspInner, &pcInner);
789: PCSetType(pcInner, PCKSP);
790: PCKSPSetKSP(pcInner, jac->head->ksp);
791: } else {
792: /* Use the outer solver for the inner solve, but revert the KSPPREONLY from PCFieldSplitSetFields_FieldSplit or
793: * PCFieldSplitSetIS_FieldSplit. We don't want KSPPREONLY because it makes the Schur complement inexact,
794: * preventing Schur complement reduction to be an accurate solve. Usually when an iterative solver is used for
795: * S = D - C A_inner^{-1} B, we expect S to be defined using an accurate definition of A_inner^{-1}, so we make
796: * GMRES the default. Note that it is also common to use PREONLY for S, in which case S may not be used
797: * directly, and the user is responsible for setting an inexact method for fieldsplit's A^{-1}. */
798: KSPSetType(jac->head->ksp,KSPGMRES);
799: MatSchurComplementSetKSP(jac->schur,jac->head->ksp);
800: }
801: KSPSetOperators(jac->head->ksp,jac->mat[0],jac->pmat[0]);
802: KSPSetFromOptions(jac->head->ksp);
803: MatSetFromOptions(jac->schur);
805: PetscObjectTypeCompare((PetscObject)jac->schur, MATSCHURCOMPLEMENT, &flg);
806: if (flg) { /* Need to do this otherwise PCSetUp_KSP will overwrite the amat of jac->head->ksp */
807: KSP kspInner;
808: PC pcInner;
810: MatSchurComplementGetKSP(jac->schur, &kspInner);
811: KSPGetPC(kspInner, &pcInner);
812: PetscObjectTypeCompare((PetscObject)pcInner, PCKSP, &flg);
813: if (flg) {
814: KSP ksp;
816: PCKSPGetKSP(pcInner, &ksp);
817: if (ksp == jac->head->ksp) {
818: PCSetUseAmat(pcInner, PETSC_TRUE);
819: }
820: }
821: }
822: PetscSNPrintf(schurtestoption, sizeof(schurtestoption), "-fieldsplit_%s_upper_", ilink->splitname);
823: PetscOptionsFindPairPrefix_Private(((PetscObject)pc)->options,((PetscObject)pc)->prefix, schurtestoption, NULL, &flg);
824: if (flg) {
825: DM dmInner;
827: PetscSNPrintf(schurprefix, sizeof(schurprefix), "%sfieldsplit_%s_upper_", ((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "", ilink->splitname);
828: KSPCreate(PetscObjectComm((PetscObject)pc), &jac->kspupper);
829: KSPSetErrorIfNotConverged(jac->kspupper,pc->erroriffailure);
830: KSPSetOptionsPrefix(jac->kspupper, schurprefix);
831: PetscObjectIncrementTabLevel((PetscObject)jac->kspupper, (PetscObject) pc, 1);
832: PetscObjectIncrementTabLevel((PetscObject)jac->kspupper->pc, (PetscObject) pc, 1);
833: KSPGetDM(jac->head->ksp, &dmInner);
834: KSPSetDM(jac->kspupper, dmInner);
835: KSPSetDMActive(jac->kspupper, PETSC_FALSE);
836: KSPSetFromOptions(jac->kspupper);
837: KSPSetOperators(jac->kspupper,jac->mat[0],jac->pmat[0]);
838: VecDuplicate(jac->head->x, &jac->head->z);
839: } else {
840: jac->kspupper = jac->head->ksp;
841: PetscObjectReference((PetscObject) jac->head->ksp);
842: }
844: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELFP) {
845: MatSchurComplementGetPmat(jac->schur,MAT_INITIAL_MATRIX,&jac->schurp);
846: }
847: KSPCreate(PetscObjectComm((PetscObject)pc),&jac->kspschur);
848: KSPSetErrorIfNotConverged(jac->kspschur,pc->erroriffailure);
849: PetscLogObjectParent((PetscObject)pc,(PetscObject)jac->kspschur);
850: PetscObjectIncrementTabLevel((PetscObject)jac->kspschur,(PetscObject)pc,1);
851: if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) {
852: PC pcschur;
853: KSPGetPC(jac->kspschur,&pcschur);
854: PCSetType(pcschur,PCNONE);
855: /* Note: This is bad if there exist preconditioners for MATSCHURCOMPLEMENT */
856: } else if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_FULL) {
857: MatSchurComplementComputeExplicitOperator(jac->schur, &jac->schur_user);
858: }
859: KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac));
860: KSPGetOptionsPrefix(jac->head->next->ksp, &Dprefix);
861: KSPSetOptionsPrefix(jac->kspschur, Dprefix);
862: /* propagate DM */
863: {
864: DM sdm;
865: KSPGetDM(jac->head->next->ksp, &sdm);
866: if (sdm) {
867: KSPSetDM(jac->kspschur, sdm);
868: KSPSetDMActive(jac->kspschur, PETSC_FALSE);
869: }
870: }
871: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
872: /* need to call this every time, since the jac->kspschur is freshly created, otherwise its options never get set */
873: KSPSetFromOptions(jac->kspschur);
874: }
875: MatAssemblyBegin(jac->schur,MAT_FINAL_ASSEMBLY);
876: MatAssemblyEnd(jac->schur,MAT_FINAL_ASSEMBLY);
878: /* HACK: special support to forward L and Lp matrices that might be used by PCLSC */
879: PetscSNPrintf(lscname,sizeof(lscname),"%s_LSC_L",ilink->splitname);
880: PetscObjectQuery((PetscObject)pc->mat,lscname,(PetscObject*)&LSC_L);
881: if (!LSC_L) {PetscObjectQuery((PetscObject)pc->pmat,lscname,(PetscObject*)&LSC_L);}
882: if (LSC_L) {PetscObjectCompose((PetscObject)jac->schur,"LSC_L",(PetscObject)LSC_L);}
883: PetscSNPrintf(lscname,sizeof(lscname),"%s_LSC_Lp",ilink->splitname);
884: PetscObjectQuery((PetscObject)pc->pmat,lscname,(PetscObject*)&LSC_L);
885: if (!LSC_L) {PetscObjectQuery((PetscObject)pc->mat,lscname,(PetscObject*)&LSC_L);}
886: if (LSC_L) {PetscObjectCompose((PetscObject)jac->schur,"LSC_Lp",(PetscObject)LSC_L);}
887: } else {
888: /* set up the individual splits' PCs */
889: i = 0;
890: ilink = jac->head;
891: while (ilink) {
892: KSPSetOperators(ilink->ksp,jac->mat[i],jac->pmat[i]);
893: /* really want setfromoptions called in PCSetFromOptions_FieldSplit(), but it is not ready yet */
894: if (!jac->suboptionsset) {KSPSetFromOptions(ilink->ksp);}
895: i++;
896: ilink = ilink->next;
897: }
898: }
900: jac->suboptionsset = PETSC_TRUE;
901: return(0);
902: }
904: #define FieldSplitSplitSolveAdd(ilink,xx,yy) \
905: (VecScatterBegin(ilink->sctx,xx,ilink->x,INSERT_VALUES,SCATTER_FORWARD) || \
906: VecScatterEnd(ilink->sctx,xx,ilink->x,INSERT_VALUES,SCATTER_FORWARD) || \
907: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL) ||\
908: KSPSolve(ilink->ksp,ilink->x,ilink->y) || \
909: PetscLogEventEnd(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL) ||\
910: VecScatterBegin(ilink->sctx,ilink->y,yy,ADD_VALUES,SCATTER_REVERSE) || \
911: VecScatterEnd(ilink->sctx,ilink->y,yy,ADD_VALUES,SCATTER_REVERSE))
913: static PetscErrorCode PCApply_FieldSplit_Schur(PC pc,Vec x,Vec y)
914: {
915: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
916: PetscErrorCode ierr;
917: PC_FieldSplitLink ilinkA = jac->head, ilinkD = ilinkA->next;
918: KSP kspA = ilinkA->ksp, kspLower = kspA, kspUpper = jac->kspupper;
921: switch (jac->schurfactorization) {
922: case PC_FIELDSPLIT_SCHUR_FACT_DIAG:
923: /* [A00 0; 0 -S], positive definite, suitable for MINRES */
924: VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);
925: VecScatterBegin(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);
926: VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);
927: PetscLogEventBegin(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
928: KSPSolve(kspA,ilinkA->x,ilinkA->y);
929: PetscLogEventEnd(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
930: VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
931: VecScatterEnd(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);
932: PetscLogEventBegin(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL);
933: KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);
934: PetscLogEventEnd(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL);
935: VecScale(ilinkD->y,jac->schurscale);
936: VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
937: VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
938: VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
939: break;
940: case PC_FIELDSPLIT_SCHUR_FACT_LOWER:
941: /* [A00 0; A10 S], suitable for left preconditioning */
942: VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);
943: VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);
944: PetscLogEventBegin(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
945: KSPSolve(kspA,ilinkA->x,ilinkA->y);
946: PetscLogEventEnd(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
947: MatMult(jac->C,ilinkA->y,ilinkD->x);
948: VecScale(ilinkD->x,-1.);
949: VecScatterBegin(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);
950: VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
951: VecScatterEnd(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);
952: PetscLogEventBegin(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL);
953: KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);
954: PetscLogEventEnd(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL);
955: VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
956: VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
957: VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
958: break;
959: case PC_FIELDSPLIT_SCHUR_FACT_UPPER:
960: /* [A00 A01; 0 S], suitable for right preconditioning */
961: VecScatterBegin(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);
962: VecScatterEnd(ilinkD->sctx,x,ilinkD->x,INSERT_VALUES,SCATTER_FORWARD);
963: PetscLogEventBegin(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL);
964: KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);
965: PetscLogEventEnd(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL); MatMult(jac->B,ilinkD->y,ilinkA->x);
966: VecScale(ilinkA->x,-1.);
967: VecScatterBegin(ilinkA->sctx,x,ilinkA->x,ADD_VALUES,SCATTER_FORWARD);
968: VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
969: VecScatterEnd(ilinkA->sctx,x,ilinkA->x,ADD_VALUES,SCATTER_FORWARD);
970: PetscLogEventBegin(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
971: KSPSolve(kspA,ilinkA->x,ilinkA->y);
972: PetscLogEventEnd(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
973: VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
974: VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
975: VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
976: break;
977: case PC_FIELDSPLIT_SCHUR_FACT_FULL:
978: /* [1 0; A10 A00^{-1} 1] [A00 0; 0 S] [1 A00^{-1}A01; 0 1], an exact solve if applied exactly, needs one extra solve with A */
979: VecScatterBegin(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);
980: VecScatterEnd(ilinkA->sctx,x,ilinkA->x,INSERT_VALUES,SCATTER_FORWARD);
981: PetscLogEventBegin(KSP_Solve_FS_L,kspLower,ilinkA->x,ilinkA->y,NULL);
982: KSPSolve(kspLower,ilinkA->x,ilinkA->y);
983: PetscLogEventEnd(KSP_Solve_FS_L,kspLower,ilinkA->x,ilinkA->y,NULL);
984: MatMult(jac->C,ilinkA->y,ilinkD->x);
985: VecScale(ilinkD->x,-1.0);
986: VecScatterBegin(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);
987: VecScatterEnd(ilinkD->sctx,x,ilinkD->x,ADD_VALUES,SCATTER_FORWARD);
989: PetscLogEventBegin(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL);
990: KSPSolve(jac->kspschur,ilinkD->x,ilinkD->y);
991: PetscLogEventEnd(KSP_Solve_FS_S,jac->kspschur,ilinkD->x,ilinkD->y,NULL);
992: VecScatterBegin(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
993: VecScatterEnd(ilinkD->sctx,ilinkD->y,y,INSERT_VALUES,SCATTER_REVERSE);
995: if (kspUpper == kspA) {
996: MatMult(jac->B,ilinkD->y,ilinkA->y);
997: VecAXPY(ilinkA->x,-1.0,ilinkA->y);
998: PetscLogEventBegin(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
999: KSPSolve(kspA,ilinkA->x,ilinkA->y);
1000: PetscLogEventEnd(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
1001: } else {
1002: PetscLogEventBegin(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
1003: KSPSolve(kspA,ilinkA->x,ilinkA->y);
1004: PetscLogEventEnd(ilinkA->event,kspA,ilinkA->x,ilinkA->y,NULL);
1005: MatMult(jac->B,ilinkD->y,ilinkA->x);
1006: PetscLogEventBegin(KSP_Solve_FS_U,kspUpper,ilinkA->x,ilinkA->z,NULL);
1007: KSPSolve(kspUpper,ilinkA->x,ilinkA->z);
1008: PetscLogEventEnd(KSP_Solve_FS_U,kspUpper,ilinkA->x,ilinkA->z,NULL);
1009: VecAXPY(ilinkA->y,-1.0,ilinkA->z);
1010: }
1011: VecScatterBegin(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
1012: VecScatterEnd(ilinkA->sctx,ilinkA->y,y,INSERT_VALUES,SCATTER_REVERSE);
1013: }
1014: return(0);
1015: }
1017: static PetscErrorCode PCApply_FieldSplit(PC pc,Vec x,Vec y)
1018: {
1019: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1020: PetscErrorCode ierr;
1021: PC_FieldSplitLink ilink = jac->head;
1022: PetscInt cnt,bs;
1023: KSPConvergedReason reason;
1026: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1027: if (jac->defaultsplit) {
1028: VecGetBlockSize(x,&bs);
1029: if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of x vector %D does not match fieldsplit blocksize %D",bs,jac->bs);
1030: VecGetBlockSize(y,&bs);
1031: if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of y vector %D does not match fieldsplit blocksize %D",bs,jac->bs);
1032: VecStrideGatherAll(x,jac->x,INSERT_VALUES);
1033: while (ilink) {
1034: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1035: KSPSolve(ilink->ksp,ilink->x,ilink->y);
1036: PetscLogEventEnd(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1037: KSPGetConvergedReason(ilink->ksp,&reason);
1038: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1039: pc->failedreason = PC_SUBPC_ERROR;
1040: }
1041: ilink = ilink->next;
1042: }
1043: VecStrideScatterAll(jac->y,y,INSERT_VALUES);
1044: } else {
1045: VecSet(y,0.0);
1046: while (ilink) {
1047: FieldSplitSplitSolveAdd(ilink,x,y);
1048: KSPGetConvergedReason(ilink->ksp,&reason);
1049: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1050: pc->failedreason = PC_SUBPC_ERROR;
1051: }
1052: ilink = ilink->next;
1053: }
1054: }
1055: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE && jac->nsplits == 2) {
1056: VecSet(y,0.0);
1057: /* solve on first block for first block variables */
1058: VecScatterBegin(ilink->sctx,x,ilink->x,INSERT_VALUES,SCATTER_FORWARD);
1059: VecScatterEnd(ilink->sctx,x,ilink->x,INSERT_VALUES,SCATTER_FORWARD);
1060: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1061: KSPSolve(ilink->ksp,ilink->x,ilink->y);
1062: PetscLogEventEnd(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1063: KSPGetConvergedReason(ilink->ksp,&reason);
1064: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1065: pc->failedreason = PC_SUBPC_ERROR;
1066: }
1067: VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1068: VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1070: /* compute the residual only onto second block variables using first block variables */
1071: MatMult(jac->Afield[1],ilink->y,ilink->next->x);
1072: ilink = ilink->next;
1073: VecScale(ilink->x,-1.0);
1074: VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);
1075: VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);
1077: /* solve on second block variables */
1078: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1079: KSPSolve(ilink->ksp,ilink->x,ilink->y);
1080: PetscLogEventEnd(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1081: KSPGetConvergedReason(ilink->ksp,&reason);
1082: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1083: pc->failedreason = PC_SUBPC_ERROR;
1084: }
1085: VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1086: VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1087: } else if (jac->type == PC_COMPOSITE_MULTIPLICATIVE || jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1088: if (!jac->w1) {
1089: VecDuplicate(x,&jac->w1);
1090: VecDuplicate(x,&jac->w2);
1091: }
1092: VecSet(y,0.0);
1093: FieldSplitSplitSolveAdd(ilink,x,y);
1094: KSPGetConvergedReason(ilink->ksp,&reason);
1095: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1096: pc->failedreason = PC_SUBPC_ERROR;
1097: }
1098: cnt = 1;
1099: while (ilink->next) {
1100: ilink = ilink->next;
1101: /* compute the residual only over the part of the vector needed */
1102: MatMult(jac->Afield[cnt++],y,ilink->x);
1103: VecScale(ilink->x,-1.0);
1104: VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);
1105: VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);
1106: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1107: KSPSolve(ilink->ksp,ilink->x,ilink->y);
1108: PetscLogEventEnd(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1109: KSPGetConvergedReason(ilink->ksp,&reason);
1110: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1111: pc->failedreason = PC_SUBPC_ERROR;
1112: }
1113: VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1114: VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1115: }
1116: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1117: cnt -= 2;
1118: while (ilink->previous) {
1119: ilink = ilink->previous;
1120: /* compute the residual only over the part of the vector needed */
1121: MatMult(jac->Afield[cnt--],y,ilink->x);
1122: VecScale(ilink->x,-1.0);
1123: VecScatterBegin(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);
1124: VecScatterEnd(ilink->sctx,x,ilink->x,ADD_VALUES,SCATTER_FORWARD);
1125: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1126: KSPSolve(ilink->ksp,ilink->x,ilink->y);
1127: PetscLogEventEnd(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1128: KSPGetConvergedReason(ilink->ksp,&reason);
1129: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1130: pc->failedreason = PC_SUBPC_ERROR;
1131: }
1132: VecScatterBegin(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1133: VecScatterEnd(ilink->sctx,ilink->y,y,ADD_VALUES,SCATTER_REVERSE);
1134: }
1135: }
1136: } else SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Unsupported or unknown composition",(int) jac->type);
1137: return(0);
1138: }
1140: #define FieldSplitSplitSolveAddTranspose(ilink,xx,yy) \
1141: (VecScatterBegin(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \
1142: VecScatterEnd(ilink->sctx,xx,ilink->y,INSERT_VALUES,SCATTER_FORWARD) || \
1143: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->y,ilink->x,NULL) || \
1144: KSPSolveTranspose(ilink->ksp,ilink->y,ilink->x) || \
1145: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->y,ilink->x,NULL) || \
1146: VecScatterBegin(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE) || \
1147: VecScatterEnd(ilink->sctx,ilink->x,yy,ADD_VALUES,SCATTER_REVERSE))
1149: static PetscErrorCode PCApplyTranspose_FieldSplit(PC pc,Vec x,Vec y)
1150: {
1151: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1152: PetscErrorCode ierr;
1153: PC_FieldSplitLink ilink = jac->head;
1154: PetscInt bs;
1155: KSPConvergedReason reason;
1158: if (jac->type == PC_COMPOSITE_ADDITIVE) {
1159: if (jac->defaultsplit) {
1160: VecGetBlockSize(x,&bs);
1161: if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of x vector %D does not match fieldsplit blocksize %D",bs,jac->bs);
1162: VecGetBlockSize(y,&bs);
1163: if (jac->bs > 0 && bs != jac->bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Blocksize of y vector %D does not match fieldsplit blocksize %D",bs,jac->bs);
1164: VecStrideGatherAll(x,jac->x,INSERT_VALUES);
1165: while (ilink) {
1166: PetscLogEventBegin(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1167: KSPSolveTranspose(ilink->ksp,ilink->x,ilink->y);
1168: PetscLogEventEnd(ilink->event,ilink->ksp,ilink->x,ilink->y,NULL);
1169: KSPGetConvergedReason(ilink->ksp,&reason);
1170: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1171: pc->failedreason = PC_SUBPC_ERROR;
1172: }
1173: ilink = ilink->next;
1174: }
1175: VecStrideScatterAll(jac->y,y,INSERT_VALUES);
1176: } else {
1177: VecSet(y,0.0);
1178: while (ilink) {
1179: FieldSplitSplitSolveAddTranspose(ilink,x,y);
1180: KSPGetConvergedReason(ilink->ksp,&reason);
1181: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1182: pc->failedreason = PC_SUBPC_ERROR;
1183: }
1184: ilink = ilink->next;
1185: }
1186: }
1187: } else {
1188: if (!jac->w1) {
1189: VecDuplicate(x,&jac->w1);
1190: VecDuplicate(x,&jac->w2);
1191: }
1192: VecSet(y,0.0);
1193: if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
1194: FieldSplitSplitSolveAddTranspose(ilink,x,y);
1195: KSPGetConvergedReason(ilink->ksp,&reason);
1196: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1197: pc->failedreason = PC_SUBPC_ERROR;
1198: }
1199: while (ilink->next) {
1200: ilink = ilink->next;
1201: MatMultTranspose(pc->mat,y,jac->w1);
1202: VecWAXPY(jac->w2,-1.0,jac->w1,x);
1203: FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);
1204: }
1205: while (ilink->previous) {
1206: ilink = ilink->previous;
1207: MatMultTranspose(pc->mat,y,jac->w1);
1208: VecWAXPY(jac->w2,-1.0,jac->w1,x);
1209: FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);
1210: }
1211: } else {
1212: while (ilink->next) { /* get to last entry in linked list */
1213: ilink = ilink->next;
1214: }
1215: FieldSplitSplitSolveAddTranspose(ilink,x,y);
1216: KSPGetConvergedReason(ilink->ksp,&reason);
1217: if (reason == KSP_DIVERGED_PCSETUP_FAILED) {
1218: pc->failedreason = PC_SUBPC_ERROR;
1219: }
1220: while (ilink->previous) {
1221: ilink = ilink->previous;
1222: MatMultTranspose(pc->mat,y,jac->w1);
1223: VecWAXPY(jac->w2,-1.0,jac->w1,x);
1224: FieldSplitSplitSolveAddTranspose(ilink,jac->w2,y);
1225: }
1226: }
1227: }
1228: return(0);
1229: }
1231: static PetscErrorCode PCReset_FieldSplit(PC pc)
1232: {
1233: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1234: PetscErrorCode ierr;
1235: PC_FieldSplitLink ilink = jac->head,next;
1238: while (ilink) {
1239: KSPDestroy(&ilink->ksp);
1240: VecDestroy(&ilink->x);
1241: VecDestroy(&ilink->y);
1242: VecDestroy(&ilink->z);
1243: VecScatterDestroy(&ilink->sctx);
1244: ISDestroy(&ilink->is);
1245: ISDestroy(&ilink->is_col);
1246: PetscFree(ilink->splitname);
1247: PetscFree(ilink->fields);
1248: PetscFree(ilink->fields_col);
1249: next = ilink->next;
1250: PetscFree(ilink);
1251: ilink = next;
1252: }
1253: jac->head = NULL;
1254: PetscFree2(jac->x,jac->y);
1255: if (jac->mat && jac->mat != jac->pmat) {
1256: MatDestroyMatrices(jac->nsplits,&jac->mat);
1257: } else if (jac->mat) {
1258: jac->mat = NULL;
1259: }
1260: if (jac->pmat) {MatDestroyMatrices(jac->nsplits,&jac->pmat);}
1261: if (jac->Afield) {MatDestroyMatrices(jac->nsplits,&jac->Afield);}
1262: jac->nsplits = 0;
1263: VecDestroy(&jac->w1);
1264: VecDestroy(&jac->w2);
1265: MatDestroy(&jac->schur);
1266: MatDestroy(&jac->schurp);
1267: MatDestroy(&jac->schur_user);
1268: KSPDestroy(&jac->kspschur);
1269: KSPDestroy(&jac->kspupper);
1270: MatDestroy(&jac->B);
1271: MatDestroy(&jac->C);
1272: jac->isrestrict = PETSC_FALSE;
1273: return(0);
1274: }
1276: static PetscErrorCode PCDestroy_FieldSplit(PC pc)
1277: {
1278: PetscErrorCode ierr;
1281: PCReset_FieldSplit(pc);
1282: PetscFree(pc->data);
1283: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurGetSubKSP_C",NULL);
1284: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",NULL);
1285: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C",NULL);
1286: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C",NULL);
1287: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C",NULL);
1288: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C",NULL);
1289: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurPre_C",NULL);
1290: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSchurPre_C",NULL);
1291: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",NULL);
1292: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitRestrictIS_C",NULL);
1293: return(0);
1294: }
1296: static PetscErrorCode PCSetFromOptions_FieldSplit(PetscOptionItems *PetscOptionsObject,PC pc)
1297: {
1298: PetscErrorCode ierr;
1299: PetscInt bs;
1300: PetscBool flg;
1301: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1302: PCCompositeType ctype;
1305: PetscOptionsHead(PetscOptionsObject,"FieldSplit options");
1306: PetscOptionsBool("-pc_fieldsplit_dm_splits","Whether to use DMCreateFieldDecomposition() for splits","PCFieldSplitSetDMSplits",jac->dm_splits,&jac->dm_splits,NULL);
1307: PetscOptionsInt("-pc_fieldsplit_block_size","Blocksize that defines number of fields","PCFieldSplitSetBlockSize",jac->bs,&bs,&flg);
1308: if (flg) {
1309: PCFieldSplitSetBlockSize(pc,bs);
1310: }
1311: jac->diag_use_amat = pc->useAmat;
1312: 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);
1313: jac->offdiag_use_amat = pc->useAmat;
1314: 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);
1315: PetscOptionsBool("-pc_fieldsplit_detect_saddle_point","Form 2-way split by detecting zero diagonal entries", "PCFieldSplitSetDetectSaddlePoint",jac->detect,&jac->detect,NULL);
1316: PCFieldSplitSetDetectSaddlePoint(pc,jac->detect); /* Sets split type and Schur PC type */
1317: PetscOptionsEnum("-pc_fieldsplit_type","Type of composition","PCFieldSplitSetType",PCCompositeTypes,(PetscEnum)jac->type,(PetscEnum*)&ctype,&flg);
1318: if (flg) {
1319: PCFieldSplitSetType(pc,ctype);
1320: }
1321: /* Only setup fields once */
1322: if ((jac->bs > 0) && (jac->nsplits == 0)) {
1323: /* only allow user to set fields from command line if bs is already known.
1324: otherwise user can set them in PCFieldSplitSetDefaults() */
1325: PCFieldSplitSetRuntimeSplits_Private(pc);
1326: if (jac->splitdefined) {PetscInfo(pc,"Splits defined using the options database\n");}
1327: }
1328: if (jac->type == PC_COMPOSITE_SCHUR) {
1329: PetscOptionsGetEnum(((PetscObject)pc)->options,((PetscObject)pc)->prefix,"-pc_fieldsplit_schur_factorization_type",PCFieldSplitSchurFactTypes,(PetscEnum*)&jac->schurfactorization,&flg);
1330: if (flg) {PetscInfo(pc,"Deprecated use of -pc_fieldsplit_schur_factorization_type\n");}
1331: 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);
1332: PetscOptionsEnum("-pc_fieldsplit_schur_precondition","How to build preconditioner for Schur complement","PCFieldSplitSetSchurPre",PCFieldSplitSchurPreTypes,(PetscEnum)jac->schurpre,(PetscEnum*)&jac->schurpre,NULL);
1333: PetscOptionsScalar("-pc_fieldsplit_schur_scale","Scale Schur complement","PCFieldSplitSetSchurScale",jac->schurscale,&jac->schurscale,NULL);
1334: }
1335: PetscOptionsTail();
1336: return(0);
1337: }
1339: /*------------------------------------------------------------------------------------*/
1341: static PetscErrorCode PCFieldSplitSetFields_FieldSplit(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col)
1342: {
1343: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1344: PetscErrorCode ierr;
1345: PC_FieldSplitLink ilink,next = jac->head;
1346: char prefix[128];
1347: PetscInt i;
1350: if (jac->splitdefined) {
1351: PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);
1352: return(0);
1353: }
1354: for (i=0; i<n; i++) {
1355: if (fields[i] >= jac->bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Field %D requested but only %D exist",fields[i],jac->bs);
1356: if (fields[i] < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative field %D requested",fields[i]);
1357: }
1358: PetscNew(&ilink);
1359: if (splitname) {
1360: PetscStrallocpy(splitname,&ilink->splitname);
1361: } else {
1362: PetscMalloc1(3,&ilink->splitname);
1363: PetscSNPrintf(ilink->splitname,2,"%s",jac->nsplits);
1364: }
1365: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + jac->nsplits : KSP_Solve_FS_0 + 4; /* Any split great than 4 gets logged in the 4th split */
1366: PetscMalloc1(n,&ilink->fields);
1367: PetscMemcpy(ilink->fields,fields,n*sizeof(PetscInt));
1368: PetscMalloc1(n,&ilink->fields_col);
1369: PetscMemcpy(ilink->fields_col,fields_col,n*sizeof(PetscInt));
1371: ilink->nfields = n;
1372: ilink->next = NULL;
1373: KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);
1374: KSPSetErrorIfNotConverged(ilink->ksp,pc->erroriffailure);
1375: PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);
1376: KSPSetType(ilink->ksp,KSPPREONLY);
1377: PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);
1379: PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);
1380: KSPSetOptionsPrefix(ilink->ksp,prefix);
1382: if (!next) {
1383: jac->head = ilink;
1384: ilink->previous = NULL;
1385: } else {
1386: while (next->next) {
1387: next = next->next;
1388: }
1389: next->next = ilink;
1390: ilink->previous = next;
1391: }
1392: jac->nsplits++;
1393: return(0);
1394: }
1396: static PetscErrorCode PCFieldSplitSchurGetSubKSP_FieldSplit(PC pc,PetscInt *n,KSP **subksp)
1397: {
1398: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1402: *subksp = NULL;
1403: if (n) *n = 0;
1404: if (jac->type == PC_COMPOSITE_SCHUR) {
1405: PetscInt nn;
1407: if (!jac->schur) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitSchurGetSubKSP()");
1408: if (jac->nsplits != 2) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_PLIB,"Unexpected number of splits %D != 2",jac->nsplits);
1409: nn = jac->nsplits + (jac->kspupper != jac->head->ksp ? 1 : 0);
1410: PetscMalloc1(nn,subksp);
1411: (*subksp)[0] = jac->head->ksp;
1412: (*subksp)[1] = jac->kspschur;
1413: if (jac->kspupper != jac->head->ksp) (*subksp)[2] = jac->kspupper;
1414: if (n) *n = nn;
1415: }
1416: return(0);
1417: }
1419: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit_Schur(PC pc,PetscInt *n,KSP **subksp)
1420: {
1421: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1425: if (!jac->schur) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must call KSPSetUp() or PCSetUp() before calling PCFieldSplitGetSubKSP()");
1426: PetscMalloc1(jac->nsplits,subksp);
1427: MatSchurComplementGetKSP(jac->schur,*subksp);
1429: (*subksp)[1] = jac->kspschur;
1430: if (n) *n = jac->nsplits;
1431: return(0);
1432: }
1434: static PetscErrorCode PCFieldSplitGetSubKSP_FieldSplit(PC pc,PetscInt *n,KSP **subksp)
1435: {
1436: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1437: PetscErrorCode ierr;
1438: PetscInt cnt = 0;
1439: PC_FieldSplitLink ilink = jac->head;
1442: PetscMalloc1(jac->nsplits,subksp);
1443: while (ilink) {
1444: (*subksp)[cnt++] = ilink->ksp;
1445: ilink = ilink->next;
1446: }
1447: if (cnt != jac->nsplits) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Corrupt PCFIELDSPLIT object: number of splits in linked list %D does not match number in object %D",cnt,jac->nsplits);
1448: if (n) *n = jac->nsplits;
1449: return(0);
1450: }
1452: /*@C
1453: PCFieldSplitRestrictIS - Restricts the fieldsplit ISs to be within a given IS.
1455: Input Parameters:
1456: + pc - the preconditioner context
1457: + is - the index set that defines the indices to which the fieldsplit is to be restricted
1459: Level: advanced
1461: @*/
1462: PetscErrorCode PCFieldSplitRestrictIS(PC pc,IS isy)
1463: {
1469: PetscTryMethod(pc,"PCFieldSplitRestrictIS_C",(PC,IS),(pc,isy));
1470: return(0);
1471: }
1474: static PetscErrorCode PCFieldSplitRestrictIS_FieldSplit(PC pc, IS isy)
1475: {
1476: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1477: PetscErrorCode ierr;
1478: PC_FieldSplitLink ilink = jac->head, next;
1479: PetscInt localsize,size,sizez,i;
1480: const PetscInt *ind, *indz;
1481: PetscInt *indc, *indcz;
1482: PetscBool flg;
1485: ISGetLocalSize(isy,&localsize);
1486: MPI_Scan(&localsize,&size,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)isy));
1487: size -= localsize;
1488: while(ilink) {
1489: IS isrl,isr;
1490: PC subpc;
1491: ISEmbed(ilink->is, isy, PETSC_TRUE, &isrl);
1492: ISGetLocalSize(isrl,&localsize);
1493: PetscMalloc1(localsize,&indc);
1494: ISGetIndices(isrl,&ind);
1495: PetscMemcpy(indc,ind,localsize*sizeof(PetscInt));
1496: ISRestoreIndices(isrl,&ind);
1497: ISDestroy(&isrl);
1498: for (i=0; i<localsize; i++) *(indc+i) += size;
1499: ISCreateGeneral(PetscObjectComm((PetscObject)isy),localsize,indc,PETSC_OWN_POINTER,&isr);
1500: PetscObjectReference((PetscObject)isr);
1501: ISDestroy(&ilink->is);
1502: ilink->is = isr;
1503: PetscObjectReference((PetscObject)isr);
1504: ISDestroy(&ilink->is_col);
1505: ilink->is_col = isr;
1506: ISDestroy(&isr);
1507: KSPGetPC(ilink->ksp, &subpc);
1508: PetscObjectTypeCompare((PetscObject)subpc,PCFIELDSPLIT,&flg);
1509: if(flg) {
1510: IS iszl,isz;
1511: MPI_Comm comm;
1512: ISGetLocalSize(ilink->is,&localsize);
1513: comm = PetscObjectComm((PetscObject)ilink->is);
1514: ISEmbed(isy, ilink->is, PETSC_TRUE, &iszl);
1515: MPI_Scan(&localsize,&sizez,1,MPIU_INT,MPI_SUM,comm);
1516: sizez -= localsize;
1517: ISGetLocalSize(iszl,&localsize);
1518: PetscMalloc1(localsize,&indcz);
1519: ISGetIndices(iszl,&indz);
1520: PetscMemcpy(indcz,indz,localsize*sizeof(PetscInt));
1521: ISRestoreIndices(iszl,&indz);
1522: ISDestroy(&iszl);
1523: for (i=0; i<localsize; i++) *(indcz+i) += sizez;
1524: ISCreateGeneral(comm,localsize,indcz,PETSC_OWN_POINTER,&isz);
1525: PCFieldSplitRestrictIS(subpc,isz);
1526: ISDestroy(&isz);
1527: }
1528: next = ilink->next;
1529: ilink = next;
1530: }
1531: jac->isrestrict = PETSC_TRUE;
1532: return(0);
1533: }
1535: static PetscErrorCode PCFieldSplitSetIS_FieldSplit(PC pc,const char splitname[],IS is)
1536: {
1537: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1538: PetscErrorCode ierr;
1539: PC_FieldSplitLink ilink, next = jac->head;
1540: char prefix[128];
1543: if (jac->splitdefined) {
1544: PetscInfo1(pc,"Ignoring new split \"%s\" because the splits have already been defined\n",splitname);
1545: return(0);
1546: }
1547: PetscNew(&ilink);
1548: if (splitname) {
1549: PetscStrallocpy(splitname,&ilink->splitname);
1550: } else {
1551: PetscMalloc1(8,&ilink->splitname);
1552: PetscSNPrintf(ilink->splitname,7,"%D",jac->nsplits);
1553: }
1554: ilink->event = jac->nsplits < 5 ? KSP_Solve_FS_0 + jac->nsplits : KSP_Solve_FS_0 + 4; /* Any split great than 4 gets logged in the 4th split */
1555: PetscObjectReference((PetscObject)is);
1556: ISDestroy(&ilink->is);
1557: ilink->is = is;
1558: PetscObjectReference((PetscObject)is);
1559: ISDestroy(&ilink->is_col);
1560: ilink->is_col = is;
1561: ilink->next = NULL;
1562: KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);
1563: KSPSetErrorIfNotConverged(ilink->ksp,pc->erroriffailure);
1564: PetscObjectIncrementTabLevel((PetscObject)ilink->ksp,(PetscObject)pc,1);
1565: KSPSetType(ilink->ksp,KSPPREONLY);
1566: PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->ksp);
1568: PetscSNPrintf(prefix,sizeof(prefix),"%sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",ilink->splitname);
1569: KSPSetOptionsPrefix(ilink->ksp,prefix);
1571: if (!next) {
1572: jac->head = ilink;
1573: ilink->previous = NULL;
1574: } else {
1575: while (next->next) {
1576: next = next->next;
1577: }
1578: next->next = ilink;
1579: ilink->previous = next;
1580: }
1581: jac->nsplits++;
1582: return(0);
1583: }
1585: /*@C
1586: PCFieldSplitSetFields - Sets the fields for one particular split in the field split preconditioner
1588: Logically Collective on PC
1590: Input Parameters:
1591: + pc - the preconditioner context
1592: . splitname - name of this split, if NULL the number of the split is used
1593: . n - the number of fields in this split
1594: - fields - the fields in this split
1596: Level: intermediate
1598: Notes:
1599: Use PCFieldSplitSetIS() to set a completely general set of indices as a field.
1601: The PCFieldSplitSetFields() is for defining fields as strided blocks. For example, if the block
1602: size is three then one can define a field as 0, or 1 or 2 or 0,1 or 0,2 or 1,2 which mean
1603: 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x1x3x5x7.. x12x45x78x....
1604: where the numbered entries indicate what is in the field.
1606: This function is called once per split (it creates a new split each time). Solve options
1607: for this split will be available under the prefix -fieldsplit_SPLITNAME_.
1609: Developer Note: This routine does not actually create the IS representing the split, that is delayed
1610: until PCSetUp_FieldSplit(), because information about the vector/matrix layouts may not be
1611: available when this routine is called.
1613: .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize(), PCFieldSplitSetIS()
1615: @*/
1616: PetscErrorCode PCFieldSplitSetFields(PC pc,const char splitname[],PetscInt n,const PetscInt *fields,const PetscInt *fields_col)
1617: {
1623: if (n < 1) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Provided number of fields %D in split \"%s\" not positive",n,splitname);
1625: PetscTryMethod(pc,"PCFieldSplitSetFields_C",(PC,const char[],PetscInt,const PetscInt*,const PetscInt*),(pc,splitname,n,fields,fields_col));
1626: return(0);
1627: }
1629: /*@
1630: PCFieldSplitSetDiagUseAmat - set flag indicating whether to extract diagonal blocks from Amat (rather than Pmat)
1632: Logically Collective on PC
1634: Input Parameters:
1635: + pc - the preconditioner object
1636: - flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
1638: Options Database:
1639: . -pc_fieldsplit_diag_use_amat
1641: Level: intermediate
1643: .seealso: PCFieldSplitGetDiagUseAmat(), PCFieldSplitSetOffDiagUseAmat(), PCFIELDSPLIT
1645: @*/
1646: PetscErrorCode PCFieldSplitSetDiagUseAmat(PC pc,PetscBool flg)
1647: {
1648: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1649: PetscBool isfs;
1654: PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);
1655: if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT);
1656: jac->diag_use_amat = flg;
1657: return(0);
1658: }
1660: /*@
1661: PCFieldSplitGetDiagUseAmat - get the flag indicating whether to extract diagonal blocks from Amat (rather than Pmat)
1663: Logically Collective on PC
1665: Input Parameters:
1666: . pc - the preconditioner object
1668: Output Parameters:
1669: . flg - boolean flag indicating whether or not to use Amat to extract the diagonal blocks from
1672: Level: intermediate
1674: .seealso: PCFieldSplitSetDiagUseAmat(), PCFieldSplitGetOffDiagUseAmat(), PCFIELDSPLIT
1676: @*/
1677: PetscErrorCode PCFieldSplitGetDiagUseAmat(PC pc,PetscBool *flg)
1678: {
1679: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1680: PetscBool isfs;
1686: PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);
1687: if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT);
1688: *flg = jac->diag_use_amat;
1689: return(0);
1690: }
1692: /*@
1693: PCFieldSplitSetOffDiagUseAmat - set flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat)
1695: Logically Collective on PC
1697: Input Parameters:
1698: + pc - the preconditioner object
1699: - flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
1701: Options Database:
1702: . -pc_fieldsplit_off_diag_use_amat
1704: Level: intermediate
1706: .seealso: PCFieldSplitGetOffDiagUseAmat(), PCFieldSplitSetDiagUseAmat(), PCFIELDSPLIT
1708: @*/
1709: PetscErrorCode PCFieldSplitSetOffDiagUseAmat(PC pc,PetscBool flg)
1710: {
1711: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1712: PetscBool isfs;
1717: PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);
1718: if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT);
1719: jac->offdiag_use_amat = flg;
1720: return(0);
1721: }
1723: /*@
1724: PCFieldSplitGetOffDiagUseAmat - get the flag indicating whether to extract off-diagonal blocks from Amat (rather than Pmat)
1726: Logically Collective on PC
1728: Input Parameters:
1729: . pc - the preconditioner object
1731: Output Parameters:
1732: . flg - boolean flag indicating whether or not to use Amat to extract the off-diagonal blocks from
1735: Level: intermediate
1737: .seealso: PCFieldSplitSetOffDiagUseAmat(), PCFieldSplitGetDiagUseAmat(), PCFIELDSPLIT
1739: @*/
1740: PetscErrorCode PCFieldSplitGetOffDiagUseAmat(PC pc,PetscBool *flg)
1741: {
1742: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
1743: PetscBool isfs;
1749: PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);
1750: if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"PC not of type %s",PCFIELDSPLIT);
1751: *flg = jac->offdiag_use_amat;
1752: return(0);
1753: }
1757: /*@C
1758: PCFieldSplitSetIS - Sets the exact elements for field
1760: Logically Collective on PC
1762: Input Parameters:
1763: + pc - the preconditioner context
1764: . splitname - name of this split, if NULL the number of the split is used
1765: - is - the index set that defines the vector elements in this field
1768: Notes:
1769: Use PCFieldSplitSetFields(), for fields defined by strided types.
1771: This function is called once per split (it creates a new split each time). Solve options
1772: for this split will be available under the prefix -fieldsplit_SPLITNAME_.
1774: Level: intermediate
1776: .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetBlockSize()
1778: @*/
1779: PetscErrorCode PCFieldSplitSetIS(PC pc,const char splitname[],IS is)
1780: {
1787: PetscTryMethod(pc,"PCFieldSplitSetIS_C",(PC,const char[],IS),(pc,splitname,is));
1788: return(0);
1789: }
1791: /*@C
1792: PCFieldSplitGetIS - Retrieves the elements for a field as an IS
1794: Logically Collective on PC
1796: Input Parameters:
1797: + pc - the preconditioner context
1798: - splitname - name of this split
1800: Output Parameter:
1801: - is - the index set that defines the vector elements in this field, or NULL if the field is not found
1803: Level: intermediate
1805: .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetIS()
1807: @*/
1808: PetscErrorCode PCFieldSplitGetIS(PC pc,const char splitname[],IS *is)
1809: {
1816: {
1817: PC_FieldSplit *jac = (PC_FieldSplit*) pc->data;
1818: PC_FieldSplitLink ilink = jac->head;
1819: PetscBool found;
1821: *is = NULL;
1822: while (ilink) {
1823: PetscStrcmp(ilink->splitname, splitname, &found);
1824: if (found) {
1825: *is = ilink->is;
1826: break;
1827: }
1828: ilink = ilink->next;
1829: }
1830: }
1831: return(0);
1832: }
1834: /*@
1835: PCFieldSplitSetBlockSize - Sets the block size for defining where fields start in the
1836: fieldsplit preconditioner. If not set the matrix block size is used.
1838: Logically Collective on PC
1840: Input Parameters:
1841: + pc - the preconditioner context
1842: - bs - the block size
1844: Level: intermediate
1846: .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields()
1848: @*/
1849: PetscErrorCode PCFieldSplitSetBlockSize(PC pc,PetscInt bs)
1850: {
1856: PetscTryMethod(pc,"PCFieldSplitSetBlockSize_C",(PC,PetscInt),(pc,bs));
1857: return(0);
1858: }
1860: /*@C
1861: PCFieldSplitGetSubKSP - Gets the KSP contexts for all splits
1863: Collective on KSP
1865: Input Parameter:
1866: . pc - the preconditioner context
1868: Output Parameters:
1869: + n - the number of splits
1870: - subksp - the array of KSP contexts
1872: Note:
1873: After PCFieldSplitGetSubKSP() the array of KSPs is to be freed by the user with PetscFree()
1874: (not the KSP just the array that contains them).
1876: You must call PCSetUp() before calling PCFieldSplitGetSubKSP().
1878: If the fieldsplit is of type PC_COMPOSITE_SCHUR, it returns the KSP object used inside the
1879: Schur complement and the KSP object used to iterate over the Schur complement.
1880: To access all the KSP objects used in PC_COMPOSITE_SCHUR, use PCFieldSplitSchurGetSubKSP()
1882: Fortran Usage: You must pass in a KSP array that is large enough to contain all the local KSPs.
1883: You can call PCFieldSplitGetSubKSP(pc,n,PETSC_NULL_KSP,ierr) to determine how large the
1884: KSP array must be.
1887: Level: advanced
1889: .seealso: PCFIELDSPLIT
1890: @*/
1891: PetscErrorCode PCFieldSplitGetSubKSP(PC pc,PetscInt *n,KSP *subksp[])
1892: {
1898: PetscUseMethod(pc,"PCFieldSplitGetSubKSP_C",(PC,PetscInt*,KSP **),(pc,n,subksp));
1899: return(0);
1900: }
1902: /*@C
1903: PCFieldSplitSchurGetSubKSP - Gets the KSP contexts used inside the Schur complement based PCFIELDSPLIT
1905: Collective on KSP
1907: Input Parameter:
1908: . pc - the preconditioner context
1910: Output Parameters:
1911: + n - the number of splits
1912: - subksp - the array of KSP contexts
1914: Note:
1915: After PCFieldSplitSchurGetSubKSP() the array of KSPs is to be freed by the user with PetscFree()
1916: (not the KSP just the array that contains them).
1918: You must call PCSetUp() before calling PCFieldSplitSchurGetSubKSP().
1920: If the fieldsplit type is of type PC_COMPOSITE_SCHUR, it returns (in order)
1921: - the KSP used for the (1,1) block
1922: - the KSP used for the Schur complement (not the one used for the interior Schur solver)
1923: - the KSP used for the (1,1) block in the upper triangular factor (if different from that of the (1,1) block).
1925: It returns a null array if the fieldsplit is not of type PC_COMPOSITE_SCHUR; in this case, you should use PCFieldSplitGetSubKSP().
1927: Fortran Usage: You must pass in a KSP array that is large enough to contain all the local KSPs.
1928: You can call PCFieldSplitSchurGetSubKSP(pc,n,PETSC_NULL_KSP,ierr) to determine how large the
1929: KSP array must be.
1931: Level: advanced
1933: .seealso: PCFIELDSPLIT
1934: @*/
1935: PetscErrorCode PCFieldSplitSchurGetSubKSP(PC pc,PetscInt *n,KSP *subksp[])
1936: {
1942: PetscUseMethod(pc,"PCFieldSplitSchurGetSubKSP_C",(PC,PetscInt*,KSP **),(pc,n,subksp));
1943: return(0);
1944: }
1946: /*@
1947: PCFieldSplitSetSchurPre - Indicates what operator is used to construct the preconditioner for the Schur complement.
1948: A11 matrix. Otherwise no preconditioner is used.
1950: Collective on PC
1952: Input Parameters:
1953: + pc - the preconditioner context
1954: . ptype - which matrix to use for preconditioning the Schur complement: PC_FIELDSPLIT_SCHUR_PRE_A11 (default), PC_FIELDSPLIT_SCHUR_PRE_SELF, PC_FIELDSPLIT_SCHUR_PRE_USER
1955: PC_FIELDSPLIT_SCHUR_PRE_SELFP, and PC_FIELDSPLIT_SCHUR_PRE_FULL
1956: - userpre - matrix to use for preconditioning, or NULL
1958: Options Database:
1959: . -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is a11. See notes for meaning of various arguments
1961: Notes:
1962: $ If ptype is
1963: $ a11 then the preconditioner for the Schur complement is generated from the block diagonal part of the preconditioner
1964: $ matrix associated with the Schur complement (i.e. A11), not the Schur complement matrix
1965: $ self the preconditioner for the Schur complement is generated from the symbolic representation of the Schur complement matrix:
1966: $ The only preconditioner that currently works with this symbolic respresentation matrix object is the PCLSC
1967: $ preconditioner
1968: $ user then the preconditioner for the Schur complement is generated from the user provided matrix (pre argument
1969: $ to this function).
1970: $ selfp then the preconditioning for the Schur complement is generated from an explicitly-assembled approximation Sp = A11 - A10 inv(diag(A00)) A01
1971: $ This is only a good preconditioner when diag(A00) is a good preconditioner for A00. Optionally, A00 can be
1972: $ lumped before extracting the diagonal using the additional option -fieldsplit_1_mat_schur_complement_ainv_type lump
1973: $ full then the preconditioner for the Schur complement is generated from the exact Schur complement matrix representation computed internally by PCFIELDSPLIT (this is expensive)
1974: $ useful mostly as a test that the Schur complement approach can work for your problem
1976: When solving a saddle point problem, where the A11 block is identically zero, using a11 as the ptype only makes sense
1977: with the additional option -fieldsplit_1_pc_type none. Usually for saddle point problems one would use a ptype of self and
1978: -fieldsplit_1_pc_type lsc which uses the least squares commutator to compute a preconditioner for the Schur complement.
1980: Level: intermediate
1982: .seealso: PCFieldSplitGetSchurPre(), PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType,
1983: MatSchurComplementSetAinvType(), PCLSC
1985: @*/
1986: PetscErrorCode PCFieldSplitSetSchurPre(PC pc,PCFieldSplitSchurPreType ptype,Mat pre)
1987: {
1992: PetscTryMethod(pc,"PCFieldSplitSetSchurPre_C",(PC,PCFieldSplitSchurPreType,Mat),(pc,ptype,pre));
1993: return(0);
1994: }
1996: PetscErrorCode PCFieldSplitSchurPrecondition(PC pc,PCFieldSplitSchurPreType ptype,Mat pre) {return PCFieldSplitSetSchurPre(pc,ptype,pre);} /* Deprecated name */
1998: /*@
1999: PCFieldSplitGetSchurPre - For Schur complement fieldsplit, determine how the Schur complement will be
2000: preconditioned. See PCFieldSplitSetSchurPre() for details.
2002: Logically Collective on PC
2004: Input Parameters:
2005: . pc - the preconditioner context
2007: Output Parameters:
2008: + ptype - which matrix to use for preconditioning the Schur complement: PC_FIELDSPLIT_SCHUR_PRE_A11, PC_FIELDSPLIT_SCHUR_PRE_SELF, PC_FIELDSPLIT_PRE_USER
2009: - userpre - matrix to use for preconditioning (with PC_FIELDSPLIT_PRE_USER), or NULL
2011: Level: intermediate
2013: .seealso: PCFieldSplitSetSchurPre(), PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType, PCLSC
2015: @*/
2016: PetscErrorCode PCFieldSplitGetSchurPre(PC pc,PCFieldSplitSchurPreType *ptype,Mat *pre)
2017: {
2022: PetscUseMethod(pc,"PCFieldSplitGetSchurPre_C",(PC,PCFieldSplitSchurPreType*,Mat*),(pc,ptype,pre));
2023: return(0);
2024: }
2026: /*@
2027: PCFieldSplitSchurGetS - extract the MatSchurComplement object used by this PC in case it needs to be configured separately
2029: Not collective
2031: Input Parameter:
2032: . pc - the preconditioner context
2034: Output Parameter:
2035: . S - the Schur complement matrix
2037: Notes:
2038: This matrix should not be destroyed using MatDestroy(); rather, use PCFieldSplitSchurRestoreS().
2040: Level: advanced
2042: .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSchurPreType, PCFieldSplitSetSchurPre(), MatSchurComplement, PCFieldSplitSchurRestoreS()
2044: @*/
2045: PetscErrorCode PCFieldSplitSchurGetS(PC pc,Mat *S)
2046: {
2048: const char* t;
2049: PetscBool isfs;
2050: PC_FieldSplit *jac;
2054: PetscObjectGetType((PetscObject)pc,&t);
2055: PetscStrcmp(t,PCFIELDSPLIT,&isfs);
2056: if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PC of type PCFIELDSPLIT, got %s instead",t);
2057: jac = (PC_FieldSplit*)pc->data;
2058: if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PCFIELDSPLIT of type SCHUR, got %D instead",jac->type);
2059: if (S) *S = jac->schur;
2060: return(0);
2061: }
2063: /*@
2064: PCFieldSplitSchurRestoreS - restores the MatSchurComplement object used by this PC
2066: Not collective
2068: Input Parameters:
2069: + pc - the preconditioner context
2070: . S - the Schur complement matrix
2072: Level: advanced
2074: .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSchurPreType, PCFieldSplitSetSchurPre(), MatSchurComplement, PCFieldSplitSchurGetS()
2076: @*/
2077: PetscErrorCode PCFieldSplitSchurRestoreS(PC pc,Mat *S)
2078: {
2080: const char* t;
2081: PetscBool isfs;
2082: PC_FieldSplit *jac;
2086: PetscObjectGetType((PetscObject)pc,&t);
2087: PetscStrcmp(t,PCFIELDSPLIT,&isfs);
2088: if (!isfs) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PC of type PCFIELDSPLIT, got %s instead",t);
2089: jac = (PC_FieldSplit*)pc->data;
2090: if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Expected PCFIELDSPLIT of type SCHUR, got %D instead",jac->type);
2091: if (!S || *S != jac->schur) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"MatSchurComplement restored is not the same as gotten");
2092: return(0);
2093: }
2096: static PetscErrorCode PCFieldSplitSetSchurPre_FieldSplit(PC pc,PCFieldSplitSchurPreType ptype,Mat pre)
2097: {
2098: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2102: jac->schurpre = ptype;
2103: if (ptype == PC_FIELDSPLIT_SCHUR_PRE_USER && pre) {
2104: MatDestroy(&jac->schur_user);
2105: jac->schur_user = pre;
2106: PetscObjectReference((PetscObject)jac->schur_user);
2107: }
2108: return(0);
2109: }
2111: static PetscErrorCode PCFieldSplitGetSchurPre_FieldSplit(PC pc,PCFieldSplitSchurPreType *ptype,Mat *pre)
2112: {
2113: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2116: *ptype = jac->schurpre;
2117: *pre = jac->schur_user;
2118: return(0);
2119: }
2121: /*@
2122: PCFieldSplitSetSchurFactType - sets which blocks of the approximate block factorization to retain in the preconditioner
2124: Collective on PC
2126: Input Parameters:
2127: + pc - the preconditioner context
2128: - ftype - which blocks of factorization to retain, PC_FIELDSPLIT_SCHUR_FACT_FULL is default
2130: Options Database:
2131: . -pc_fieldsplit_schur_fact_type <diag,lower,upper,full> default is full
2134: Level: intermediate
2136: Notes:
2137: The FULL factorization is
2139: $ (A B) = (1 0) (A 0) (1 Ainv*B) = L D U
2140: $ (C E) (C*Ainv 1) (0 S) (0 1 )
2142: where S = E - C*Ainv*B. In practice, the full factorization is applied via block triangular solves with the grouping L*(D*U). UPPER uses D*U, LOWER uses L*D,
2143: and DIAG is the diagonal part with the sign of S flipped (because this makes the preconditioner positive definite for many formulations, thus allowing the use of KSPMINRES). Sign flipping of S can be turned off with PCFieldSplitSetSchurScale().
2145: $ If A and S are solved exactly
2146: $ *) FULL factorization is a direct solver.
2147: $ *) 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.
2148: $ *) 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.
2150: If the iteration count is very low, consider using KSPFGMRES or KSPGCR which can use one less preconditioner
2151: application in this case. Note that the preconditioned operator may be highly non-normal, so such fast convergence may not be observed in practice.
2153: For symmetric problems in which A is positive definite and S is negative definite, DIAG can be used with KSPMINRES.
2155: Note that a flexible method like KSPFGMRES or KSPGCR 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).
2157: References:
2158: + 1. - Murphy, Golub, and Wathen, A note on preconditioning indefinite linear systems, SIAM J. Sci. Comput., 21 (2000).
2159: - 2. - Ipsen, A note on preconditioning nonsymmetric matrices, SIAM J. Sci. Comput., 23 (2001).
2161: .seealso: PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType, PCFieldSplitSetSchurScale()
2162: @*/
2163: PetscErrorCode PCFieldSplitSetSchurFactType(PC pc,PCFieldSplitSchurFactType ftype)
2164: {
2169: PetscTryMethod(pc,"PCFieldSplitSetSchurFactType_C",(PC,PCFieldSplitSchurFactType),(pc,ftype));
2170: return(0);
2171: }
2173: static PetscErrorCode PCFieldSplitSetSchurFactType_FieldSplit(PC pc,PCFieldSplitSchurFactType ftype)
2174: {
2175: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2178: jac->schurfactorization = ftype;
2179: return(0);
2180: }
2182: /*@
2183: PCFieldSplitSetSchurScale - Controls the sign flip of S for PC_FIELDSPLIT_SCHUR_FACT_DIAG.
2185: Collective on PC
2187: Input Parameters:
2188: + pc - the preconditioner context
2189: - scale - scaling factor for the Schur complement
2191: Options Database:
2192: . -pc_fieldsplit_schur_scale - default is -1.0
2194: Level: intermediate
2196: .seealso: PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurFactType, PCFieldSplitSetSchurScale()
2197: @*/
2198: PetscErrorCode PCFieldSplitSetSchurScale(PC pc,PetscScalar scale)
2199: {
2205: PetscTryMethod(pc,"PCFieldSplitSetSchurScale_C",(PC,PetscScalar),(pc,scale));
2206: return(0);
2207: }
2209: static PetscErrorCode PCFieldSplitSetSchurScale_FieldSplit(PC pc,PetscScalar scale)
2210: {
2211: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2214: jac->schurscale = scale;
2215: return(0);
2216: }
2218: /*@C
2219: PCFieldSplitGetSchurBlocks - Gets all matrix blocks for the Schur complement
2221: Collective on KSP
2223: Input Parameter:
2224: . pc - the preconditioner context
2226: Output Parameters:
2227: + A00 - the (0,0) block
2228: . A01 - the (0,1) block
2229: . A10 - the (1,0) block
2230: - A11 - the (1,1) block
2232: Level: advanced
2234: .seealso: PCFIELDSPLIT
2235: @*/
2236: PetscErrorCode PCFieldSplitGetSchurBlocks(PC pc,Mat *A00,Mat *A01,Mat *A10, Mat *A11)
2237: {
2238: PC_FieldSplit *jac = (PC_FieldSplit*) pc->data;
2242: if (jac->type != PC_COMPOSITE_SCHUR) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG, "FieldSplit is not using a Schur complement approach.");
2243: if (A00) *A00 = jac->pmat[0];
2244: if (A01) *A01 = jac->B;
2245: if (A10) *A10 = jac->C;
2246: if (A11) *A11 = jac->pmat[1];
2247: return(0);
2248: }
2250: static PetscErrorCode PCFieldSplitSetType_FieldSplit(PC pc,PCCompositeType type)
2251: {
2252: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2256: jac->type = type;
2257: if (type == PC_COMPOSITE_SCHUR) {
2258: pc->ops->apply = PCApply_FieldSplit_Schur;
2259: pc->ops->view = PCView_FieldSplit_Schur;
2261: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit_Schur);
2262: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurPre_C",PCFieldSplitSetSchurPre_FieldSplit);
2263: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSchurPre_C",PCFieldSplitGetSchurPre_FieldSplit);
2264: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",PCFieldSplitSetSchurFactType_FieldSplit);
2265: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurScale_C",PCFieldSplitSetSchurScale_FieldSplit);
2267: } else {
2268: pc->ops->apply = PCApply_FieldSplit;
2269: pc->ops->view = PCView_FieldSplit;
2271: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit);
2272: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurPre_C",0);
2273: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSchurPre_C",0);
2274: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurFactType_C",0);
2275: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetSchurScale_C",0);
2276: }
2277: return(0);
2278: }
2280: static PetscErrorCode PCFieldSplitSetBlockSize_FieldSplit(PC pc,PetscInt bs)
2281: {
2282: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2285: if (bs < 1) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Blocksize must be positive, you gave %D",bs);
2286: if (jac->bs > 0 && jac->bs != bs) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Cannot change fieldsplit blocksize from %D to %D after it has been set",jac->bs,bs);
2287: jac->bs = bs;
2288: return(0);
2289: }
2291: /*@
2292: PCFieldSplitSetType - Sets the type of fieldsplit preconditioner.
2294: Collective on PC
2296: Input Parameter:
2297: . pc - the preconditioner context
2298: . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR
2300: Options Database Key:
2301: . -pc_fieldsplit_type <type: one of multiplicative, additive, symmetric_multiplicative, special, schur> - Sets fieldsplit preconditioner type
2303: Level: Intermediate
2305: .keywords: PC, set, type, composite preconditioner, additive, multiplicative
2307: .seealso: PCCompositeSetType()
2309: @*/
2310: PetscErrorCode PCFieldSplitSetType(PC pc,PCCompositeType type)
2311: {
2316: PetscTryMethod(pc,"PCFieldSplitSetType_C",(PC,PCCompositeType),(pc,type));
2317: return(0);
2318: }
2320: /*@
2321: PCFieldSplitGetType - Gets the type of fieldsplit preconditioner.
2323: Not collective
2325: Input Parameter:
2326: . pc - the preconditioner context
2328: Output Parameter:
2329: . type - PC_COMPOSITE_ADDITIVE, PC_COMPOSITE_MULTIPLICATIVE (default), PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL, PC_COMPOSITE_SCHUR
2331: Level: Intermediate
2333: .keywords: PC, set, type, composite preconditioner, additive, multiplicative
2334: .seealso: PCCompositeSetType()
2335: @*/
2336: PetscErrorCode PCFieldSplitGetType(PC pc, PCCompositeType *type)
2337: {
2338: PC_FieldSplit *jac = (PC_FieldSplit*) pc->data;
2343: *type = jac->type;
2344: return(0);
2345: }
2347: /*@
2348: PCFieldSplitSetDMSplits - Flags whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible.
2350: Logically Collective
2352: Input Parameters:
2353: + pc - the preconditioner context
2354: - flg - boolean indicating whether to use field splits defined by the DM
2356: Options Database Key:
2357: . -pc_fieldsplit_dm_splits
2359: Level: Intermediate
2361: .keywords: PC, DM, composite preconditioner, additive, multiplicative
2363: .seealso: PCFieldSplitGetDMSplits()
2365: @*/
2366: PetscErrorCode PCFieldSplitSetDMSplits(PC pc,PetscBool flg)
2367: {
2368: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2369: PetscBool isfs;
2375: PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);
2376: if (isfs) {
2377: jac->dm_splits = flg;
2378: }
2379: return(0);
2380: }
2383: /*@
2384: PCFieldSplitGetDMSplits - Returns flag indicating whether DMCreateFieldDecomposition() should be used to define the splits, whenever possible.
2386: Logically Collective
2388: Input Parameter:
2389: . pc - the preconditioner context
2391: Output Parameter:
2392: . flg - boolean indicating whether to use field splits defined by the DM
2394: Level: Intermediate
2396: .keywords: PC, DM, composite preconditioner, additive, multiplicative
2398: .seealso: PCFieldSplitSetDMSplits()
2400: @*/
2401: PetscErrorCode PCFieldSplitGetDMSplits(PC pc,PetscBool* flg)
2402: {
2403: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2404: PetscBool isfs;
2410: PetscObjectTypeCompare((PetscObject)pc,PCFIELDSPLIT,&isfs);
2411: if (isfs) {
2412: if(flg) *flg = jac->dm_splits;
2413: }
2414: return(0);
2415: }
2417: /*@
2418: PCFieldSplitGetDetectSaddlePoint - Returns flag indicating whether PCFieldSplit will attempt to automatically determine fields based on zero diagonal entries.
2420: Logically Collective
2422: Input Parameter:
2423: . pc - the preconditioner context
2425: Output Parameter:
2426: . flg - boolean indicating whether to detect fields or not
2428: Level: Intermediate
2430: .seealso: PCFIELDSPLIT, PCFieldSplitSetDetectSaddlePoint()
2432: @*/
2433: PetscErrorCode PCFieldSplitGetDetectSaddlePoint(PC pc,PetscBool *flg)
2434: {
2435: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2438: *flg = jac->detect;
2439: return(0);
2440: }
2442: /*@
2443: PCFieldSplitSetDetectSaddlePoint - Sets flag indicating whether PCFieldSplit will attempt to automatically determine fields based on zero diagonal entries.
2445: Logically Collective
2447: Notes:
2448: Also sets the split type to PC_COMPOSITE_SCHUR (see PCFieldSplitSetType()) and the Schur preconditioner type to PC_FIELDSPLIT_SCHUR_PRE_SELF (see PCFieldSplitSetSchurPre()).
2450: Input Parameter:
2451: . pc - the preconditioner context
2453: Output Parameter:
2454: . flg - boolean indicating whether to detect fields or not
2456: Options Database Key:
2457: . -pc_fieldsplit_detect_saddle_point
2459: Level: Intermediate
2461: .seealso: PCFIELDSPLIT, PCFieldSplitSetDetectSaddlePoint(), PCFieldSplitSetType(), PCFieldSplitSetSchurPre()
2463: @*/
2464: PetscErrorCode PCFieldSplitSetDetectSaddlePoint(PC pc,PetscBool flg)
2465: {
2466: PC_FieldSplit *jac = (PC_FieldSplit*)pc->data;
2470: jac->detect = flg;
2471: if (jac->detect) {
2472: PCFieldSplitSetType(pc,PC_COMPOSITE_SCHUR);
2473: PCFieldSplitSetSchurPre(pc,PC_FIELDSPLIT_SCHUR_PRE_SELF,NULL);
2474: }
2475: return(0);
2476: }
2478: /* -------------------------------------------------------------------------------------*/
2479: /*MC
2480: PCFIELDSPLIT - Preconditioner created by combining separate preconditioners for individual
2481: fields or groups of fields. See the users manual section "Solving Block Matrices" for more details.
2483: To set options on the solvers for each block append -fieldsplit_ to all the PC
2484: options database keys. For example, -fieldsplit_pc_type ilu -fieldsplit_pc_factor_levels 1
2486: To set the options on the solvers separate for each block call PCFieldSplitGetSubKSP()
2487: and set the options directly on the resulting KSP object
2489: Level: intermediate
2491: Options Database Keys:
2492: + -pc_fieldsplit_%d_fields <a,b,..> - indicates the fields to be used in the %d'th split
2493: . -pc_fieldsplit_default - automatically add any fields to additional splits that have not
2494: been supplied explicitly by -pc_fieldsplit_%d_fields
2495: . -pc_fieldsplit_block_size <bs> - size of block that defines fields (i.e. there are bs fields)
2496: . -pc_fieldsplit_type <additive,multiplicative,symmetric_multiplicative,schur> - type of relaxation or factorization splitting
2497: . -pc_fieldsplit_schur_precondition <self,selfp,user,a11,full> - default is a11; see PCFieldSplitSetSchurPre()
2498: . -pc_fieldsplit_detect_saddle_point - automatically finds rows with zero diagonal and uses Schur complement with no preconditioner as the solver
2500: - Options prefix for inner solvers when using Schur complement preconditioner are -fieldsplit_0_ and -fieldsplit_1_
2501: for all other solvers they are -fieldsplit_%d_ for the dth field, use -fieldsplit_ for all fields
2503: Notes:
2504: Use PCFieldSplitSetFields() to set fields defined by "strided" entries and PCFieldSplitSetIS()
2505: to define a field by an arbitrary collection of entries.
2507: If no fields are set the default is used. The fields are defined by entries strided by bs,
2508: beginning at 0 then 1, etc to bs-1. The block size can be set with PCFieldSplitSetBlockSize(),
2509: if this is not called the block size defaults to the blocksize of the second matrix passed
2510: to KSPSetOperators()/PCSetOperators().
2512: $ For the Schur complement preconditioner if J = ( A00 A01 )
2513: $ ( A10 A11 )
2514: $ the preconditioner using full factorization is
2515: $ ( I -ksp(A00) A01 ) ( inv(A00) 0 ) ( I 0 )
2516: $ ( 0 I ) ( 0 ksp(S) ) ( -A10 ksp(A00) I )
2517: where the action of inv(A00) is applied using the KSP solver with prefix -fieldsplit_0_. S is the Schur complement
2518: $ S = A11 - A10 ksp(A00) A01
2519: which is usually dense and not stored explicitly. The action of ksp(S) is computed using the KSP solver with prefix -fieldsplit_splitname_ (where splitname was given
2520: in providing the SECOND split or 1 if not give). For PCFieldSplitGetSubKSP() when field number is 0,
2521: it returns the KSP associated with -fieldsplit_0_ while field number 1 gives -fieldsplit_1_ KSP. By default
2522: A11 is used to construct a preconditioner for S, use PCFieldSplitSetSchurPre() for all the possible ways to construct the preconditioner for S.
2524: The factorization type is set using -pc_fieldsplit_schur_fact_type <diag, lower, upper, full>. The full is shown above,
2525: diag gives
2526: $ ( inv(A00) 0 )
2527: $ ( 0 -ksp(S) )
2528: note that slightly counter intuitively there is a negative in front of the ksp(S) so that the preconditioner is positive definite. For SPD matrices J, the sign flip
2529: can be turned off with PCFieldSplitSetSchurScale() or by command line -pc_fieldsplit_schur_scale 1.0. The lower factorization is the inverse of
2530: $ ( A00 0 )
2531: $ ( A10 S )
2532: where the inverses of A00 and S are applied using KSPs. The upper factorization is the inverse of
2533: $ ( A00 A01 )
2534: $ ( 0 S )
2535: where again the inverses of A00 and S are applied using KSPs.
2537: If only one set of indices (one IS) is provided with PCFieldSplitSetIS() then the complement of that IS
2538: is used automatically for a second block.
2540: The fieldsplit preconditioner cannot currently be used with the BAIJ or SBAIJ data formats if the blocksize is larger than 1.
2541: Generally it should be used with the AIJ format.
2543: The forms of these preconditioners are closely related if not identical to forms derived as "Distributive Iterations", see,
2544: for example, page 294 in "Principles of Computational Fluid Dynamics" by Pieter Wesseling. Note that one can also use PCFIELDSPLIT
2545: inside a smoother resulting in "Distributive Smoothers".
2547: Concepts: physics based preconditioners, block preconditioners
2549: There is a nice discussion of block preconditioners in
2551: [El08] A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations
2552: Howard Elman, V.E. Howle, John Shadid, Robert Shuttleworth, Ray Tuminaro, Journal of Computational Physics 227 (2008) 1790--1808
2553: http://chess.cs.umd.edu/~elman/papers/tax.pdf
2555: The Constrained Pressure Preconditioner (CPR) can be implemented using PCCOMPOSITE with PCGALERKIN. CPR first solves an R A P subsystem, updates the
2556: residual on all variables (PCCompositeSetType(pc,PC_COMPOSITE_MULTIPLICATIVE)), and then applies a simple ILU like preconditioner on all the variables.
2558: .seealso: PCCreate(), PCSetType(), PCType (for list of available types), PC, Block_Preconditioners, PCLSC,
2559: PCFieldSplitGetSubKSP(), PCFieldSplitSchurGetSubKSP(), PCFieldSplitSetFields(), PCFieldSplitSetType(), PCFieldSplitSetIS(), PCFieldSplitSetSchurPre(),
2560: MatSchurComplementSetAinvType(), PCFieldSplitSetSchurScale(),
2561: PCFieldSplitSetDetectSaddlePoint()
2562: M*/
2564: PETSC_EXTERN PetscErrorCode PCCreate_FieldSplit(PC pc)
2565: {
2567: PC_FieldSplit *jac;
2570: PetscNewLog(pc,&jac);
2572: jac->bs = -1;
2573: jac->nsplits = 0;
2574: jac->type = PC_COMPOSITE_MULTIPLICATIVE;
2575: jac->schurpre = PC_FIELDSPLIT_SCHUR_PRE_USER; /* Try user preconditioner first, fall back on diagonal */
2576: jac->schurfactorization = PC_FIELDSPLIT_SCHUR_FACT_FULL;
2577: jac->schurscale = -1.0;
2578: jac->dm_splits = PETSC_TRUE;
2579: jac->detect = PETSC_FALSE;
2581: pc->data = (void*)jac;
2583: pc->ops->apply = PCApply_FieldSplit;
2584: pc->ops->applytranspose = PCApplyTranspose_FieldSplit;
2585: pc->ops->setup = PCSetUp_FieldSplit;
2586: pc->ops->reset = PCReset_FieldSplit;
2587: pc->ops->destroy = PCDestroy_FieldSplit;
2588: pc->ops->setfromoptions = PCSetFromOptions_FieldSplit;
2589: pc->ops->view = PCView_FieldSplit;
2590: pc->ops->applyrichardson = 0;
2592: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSchurGetSubKSP_C",PCFieldSplitSchurGetSubKSP_FieldSplit);
2593: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitGetSubKSP_C",PCFieldSplitGetSubKSP_FieldSplit);
2594: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetFields_C",PCFieldSplitSetFields_FieldSplit);
2595: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetIS_C",PCFieldSplitSetIS_FieldSplit);
2596: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetType_C",PCFieldSplitSetType_FieldSplit);
2597: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitSetBlockSize_C",PCFieldSplitSetBlockSize_FieldSplit);
2598: PetscObjectComposeFunction((PetscObject)pc,"PCFieldSplitRestrictIS_C",PCFieldSplitRestrictIS_FieldSplit);
2599: return(0);
2600: }