Actual source code: precon.c
2: /*
3: The PC (preconditioner) interface routines, callable by users.
4: */
5: #include <petsc/private/pcimpl.h>
6: #include <petscdm.h>
8: /* Logging support */
9: PetscClassId PC_CLASSID;
10: PetscLogEvent PC_SetUp, PC_SetUpOnBlocks, PC_Apply, PC_MatApply, PC_ApplyCoarse, PC_ApplyMultiple, PC_ApplySymmetricLeft;
11: PetscLogEvent PC_ApplySymmetricRight, PC_ModifySubMatrices, PC_ApplyOnBlocks, PC_ApplyTransposeOnBlocks;
12: PetscInt PetscMGLevelId;
14: PetscErrorCode PCGetDefaultType_Private(PC pc,const char *type[])
15: {
17: PetscMPIInt size;
18: PetscBool hasop,flg1,flg2,set,flg3;
21: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
22: if (pc->pmat) {
23: MatHasOperation(pc->pmat,MATOP_GET_DIAGONAL_BLOCK,&hasop);
24: if (size == 1) {
25: MatGetFactorAvailable(pc->pmat,"petsc",MAT_FACTOR_ICC,&flg1);
26: MatGetFactorAvailable(pc->pmat,"petsc",MAT_FACTOR_ILU,&flg2);
27: MatIsSymmetricKnown(pc->pmat,&set,&flg3);
28: if (flg1 && (!flg2 || (set && flg3))) {
29: *type = PCICC;
30: } else if (flg2) {
31: *type = PCILU;
32: } else if (hasop) { /* likely is a parallel matrix run on one processor */
33: *type = PCBJACOBI;
34: } else {
35: *type = PCNONE;
36: }
37: } else {
38: if (hasop) {
39: *type = PCBJACOBI;
40: } else {
41: *type = PCNONE;
42: }
43: }
44: } else {
45: if (size == 1) {
46: *type = PCILU;
47: } else {
48: *type = PCBJACOBI;
49: }
50: }
51: return(0);
52: }
54: /*@
55: PCReset - Resets a PC context to the pcsetupcalled = 0 state and removes any allocated Vecs and Mats
57: Collective on PC
59: Input Parameter:
60: . pc - the preconditioner context
62: Level: developer
64: Notes:
65: This allows a PC to be reused for a different sized linear system but using the same options that have been previously set in the PC
67: .seealso: PCCreate(), PCSetUp()
68: @*/
69: PetscErrorCode PCReset(PC pc)
70: {
75: if (pc->ops->reset) {
76: (*pc->ops->reset)(pc);
77: }
78: VecDestroy(&pc->diagonalscaleright);
79: VecDestroy(&pc->diagonalscaleleft);
80: MatDestroy(&pc->pmat);
81: MatDestroy(&pc->mat);
83: pc->setupcalled = 0;
84: return(0);
85: }
87: /*@C
88: PCDestroy - Destroys PC context that was created with PCCreate().
90: Collective on PC
92: Input Parameter:
93: . pc - the preconditioner context
95: Level: developer
97: .seealso: PCCreate(), PCSetUp()
98: @*/
99: PetscErrorCode PCDestroy(PC *pc)
100: {
104: if (!*pc) return(0);
106: if (--((PetscObject)(*pc))->refct > 0) {*pc = NULL; return(0);}
108: PCReset(*pc);
110: /* if memory was published with SAWs then destroy it */
111: PetscObjectSAWsViewOff((PetscObject)*pc);
112: if ((*pc)->ops->destroy) {(*(*pc)->ops->destroy)((*pc));}
113: DMDestroy(&(*pc)->dm);
114: PetscHeaderDestroy(pc);
115: return(0);
116: }
118: /*@C
119: PCGetDiagonalScale - Indicates if the preconditioner applies an additional left and right
120: scaling as needed by certain time-stepping codes.
122: Logically Collective on PC
124: Input Parameter:
125: . pc - the preconditioner context
127: Output Parameter:
128: . flag - PETSC_TRUE if it applies the scaling
130: Level: developer
132: Notes:
133: If this returns PETSC_TRUE then the system solved via the Krylov method is
134: $ D M A D^{-1} y = D M b for left preconditioning or
135: $ D A M D^{-1} z = D b for right preconditioning
137: .seealso: PCCreate(), PCSetUp(), PCDiagonalScaleLeft(), PCDiagonalScaleRight(), PCSetDiagonalScale()
138: @*/
139: PetscErrorCode PCGetDiagonalScale(PC pc,PetscBool *flag)
140: {
144: *flag = pc->diagonalscale;
145: return(0);
146: }
148: /*@
149: PCSetDiagonalScale - Indicates the left scaling to use to apply an additional left and right
150: scaling as needed by certain time-stepping codes.
152: Logically Collective on PC
154: Input Parameters:
155: + pc - the preconditioner context
156: - s - scaling vector
158: Level: intermediate
160: Notes:
161: The system solved via the Krylov method is
162: $ D M A D^{-1} y = D M b for left preconditioning or
163: $ D A M D^{-1} z = D b for right preconditioning
165: PCDiagonalScaleLeft() scales a vector by D. PCDiagonalScaleRight() scales a vector by D^{-1}.
167: .seealso: PCCreate(), PCSetUp(), PCDiagonalScaleLeft(), PCDiagonalScaleRight(), PCGetDiagonalScale()
168: @*/
169: PetscErrorCode PCSetDiagonalScale(PC pc,Vec s)
170: {
176: pc->diagonalscale = PETSC_TRUE;
178: PetscObjectReference((PetscObject)s);
179: VecDestroy(&pc->diagonalscaleleft);
181: pc->diagonalscaleleft = s;
183: VecDuplicate(s,&pc->diagonalscaleright);
184: VecCopy(s,pc->diagonalscaleright);
185: VecReciprocal(pc->diagonalscaleright);
186: return(0);
187: }
189: /*@
190: PCDiagonalScaleLeft - Scales a vector by the left scaling as needed by certain time-stepping codes.
192: Logically Collective on PC
194: Input Parameters:
195: + pc - the preconditioner context
196: . in - input vector
197: - out - scaled vector (maybe the same as in)
199: Level: intermediate
201: Notes:
202: The system solved via the Krylov method is
203: $ D M A D^{-1} y = D M b for left preconditioning or
204: $ D A M D^{-1} z = D b for right preconditioning
206: PCDiagonalScaleLeft() scales a vector by D. PCDiagonalScaleRight() scales a vector by D^{-1}.
208: If diagonal scaling is turned off and in is not out then in is copied to out
210: .seealso: PCCreate(), PCSetUp(), PCDiagonalScaleSet(), PCDiagonalScaleRight(), PCDiagonalScale()
211: @*/
212: PetscErrorCode PCDiagonalScaleLeft(PC pc,Vec in,Vec out)
213: {
220: if (pc->diagonalscale) {
221: VecPointwiseMult(out,pc->diagonalscaleleft,in);
222: } else if (in != out) {
223: VecCopy(in,out);
224: }
225: return(0);
226: }
228: /*@
229: PCDiagonalScaleRight - Scales a vector by the right scaling as needed by certain time-stepping codes.
231: Logically Collective on PC
233: Input Parameters:
234: + pc - the preconditioner context
235: . in - input vector
236: - out - scaled vector (maybe the same as in)
238: Level: intermediate
240: Notes:
241: The system solved via the Krylov method is
242: $ D M A D^{-1} y = D M b for left preconditioning or
243: $ D A M D^{-1} z = D b for right preconditioning
245: PCDiagonalScaleLeft() scales a vector by D. PCDiagonalScaleRight() scales a vector by D^{-1}.
247: If diagonal scaling is turned off and in is not out then in is copied to out
249: .seealso: PCCreate(), PCSetUp(), PCDiagonalScaleLeft(), PCDiagonalScaleSet(), PCDiagonalScale()
250: @*/
251: PetscErrorCode PCDiagonalScaleRight(PC pc,Vec in,Vec out)
252: {
259: if (pc->diagonalscale) {
260: VecPointwiseMult(out,pc->diagonalscaleright,in);
261: } else if (in != out) {
262: VecCopy(in,out);
263: }
264: return(0);
265: }
267: /*@
268: PCSetUseAmat - Sets a flag to indicate that when the preconditioner needs to apply (part of) the
269: operator during the preconditioning process it applies the Amat provided to TSSetRHSJacobian(),
270: TSSetIJacobian(), SNESSetJacobian(), KSPSetOperator() or PCSetOperator() not the Pmat.
272: Logically Collective on PC
274: Input Parameters:
275: + pc - the preconditioner context
276: - flg - PETSC_TRUE to use the Amat, PETSC_FALSE to use the Pmat (default is false)
278: Options Database Key:
279: . -pc_use_amat <true,false>
281: Notes:
282: For the common case in which the linear system matrix and the matrix used to construct the
283: preconditioner are identical, this routine is does nothing.
285: Level: intermediate
287: .seealso: PCGetUseAmat(), PCBJACOBI, PGMG, PCFIELDSPLIT, PCCOMPOSITE
288: @*/
289: PetscErrorCode PCSetUseAmat(PC pc,PetscBool flg)
290: {
293: pc->useAmat = flg;
294: return(0);
295: }
297: /*@
298: PCSetErrorIfFailure - Causes PC to generate an error if a FPE, for example a zero pivot, is detected.
300: Logically Collective on PC
302: Input Parameters:
303: + pc - iterative context obtained from PCCreate()
304: - flg - PETSC_TRUE indicates you want the error generated
306: Level: advanced
308: Notes:
309: Normally PETSc continues if a linear solver fails due to a failed setup of a preconditioner, you can call KSPGetConvergedReason() after a KSPSolve()
310: to determine if it has converged or failed. Or use -ksp_error_if_not_converged to cause the program to terminate as soon as lack of convergence is
311: detected.
313: This is propagated into KSPs used by this PC, which then propagate it into PCs used by those KSPs
315: .seealso: PCGetInitialGuessNonzero(), PCSetInitialGuessKnoll(), PCGetInitialGuessKnoll()
316: @*/
317: PetscErrorCode PCSetErrorIfFailure(PC pc,PetscBool flg)
318: {
322: pc->erroriffailure = flg;
323: return(0);
324: }
326: /*@
327: PCGetUseAmat - Gets a flag to indicate that when the preconditioner needs to apply (part of) the
328: operator during the preconditioning process it applies the Amat provided to TSSetRHSJacobian(),
329: TSSetIJacobian(), SNESSetJacobian(), KSPSetOperator() or PCSetOperator() not the Pmat.
331: Logically Collective on PC
333: Input Parameter:
334: . pc - the preconditioner context
336: Output Parameter:
337: . flg - PETSC_TRUE to use the Amat, PETSC_FALSE to use the Pmat (default is false)
339: Notes:
340: For the common case in which the linear system matrix and the matrix used to construct the
341: preconditioner are identical, this routine is does nothing.
343: Level: intermediate
345: .seealso: PCSetUseAmat(), PCBJACOBI, PGMG, PCFIELDSPLIT, PCCOMPOSITE
346: @*/
347: PetscErrorCode PCGetUseAmat(PC pc,PetscBool *flg)
348: {
351: *flg = pc->useAmat;
352: return(0);
353: }
355: /*@
356: PCCreate - Creates a preconditioner context.
358: Collective
360: Input Parameter:
361: . comm - MPI communicator
363: Output Parameter:
364: . pc - location to put the preconditioner context
366: Notes:
367: The default preconditioner for sparse matrices is PCILU or PCICC with 0 fill on one process and block Jacobi with PCILU or PCICC
368: in parallel. For dense matrices it is always PCNONE.
370: Level: developer
372: .seealso: PCSetUp(), PCApply(), PCDestroy()
373: @*/
374: PetscErrorCode PCCreate(MPI_Comm comm,PC *newpc)
375: {
376: PC pc;
381: *newpc = NULL;
382: PCInitializePackage();
384: PetscHeaderCreate(pc,PC_CLASSID,"PC","Preconditioner","PC",comm,PCDestroy,PCView);
386: pc->mat = NULL;
387: pc->pmat = NULL;
388: pc->setupcalled = 0;
389: pc->setfromoptionscalled = 0;
390: pc->data = NULL;
391: pc->diagonalscale = PETSC_FALSE;
392: pc->diagonalscaleleft = NULL;
393: pc->diagonalscaleright = NULL;
395: pc->modifysubmatrices = NULL;
396: pc->modifysubmatricesP = NULL;
398: *newpc = pc;
399: return(0);
401: }
403: /* -------------------------------------------------------------------------------*/
405: /*@
406: PCApply - Applies the preconditioner to a vector.
408: Collective on PC
410: Input Parameters:
411: + pc - the preconditioner context
412: - x - input vector
414: Output Parameter:
415: . y - output vector
417: Level: developer
419: .seealso: PCApplyTranspose(), PCApplyBAorAB()
420: @*/
421: PetscErrorCode PCApply(PC pc,Vec x,Vec y)
422: {
424: PetscInt m,n,mv,nv;
430: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
431: if (pc->erroriffailure) {VecValidValues(x,2,PETSC_TRUE);}
432: /* use pmat to check vector sizes since for KSPLSQR the pmat may be of a different size than mat */
433: MatGetLocalSize(pc->pmat,&m,&n);
434: VecGetLocalSize(x,&mv);
435: VecGetLocalSize(y,&nv);
436: /* check pmat * y = x is feasible */
437: if (mv != m) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Preconditioner number of local rows %D does not equal input vector size %D",m,mv);
438: if (nv != n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Preconditioner number of local columns %D does not equal output vector size %D",n,nv);
439: VecSetErrorIfLocked(y,3);
441: PCSetUp(pc);
442: if (!pc->ops->apply) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have apply");
443: VecLockReadPush(x);
444: PetscLogEventBegin(PC_Apply,pc,x,y,0);
445: (*pc->ops->apply)(pc,x,y);
446: PetscLogEventEnd(PC_Apply,pc,x,y,0);
447: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
448: VecLockReadPop(x);
449: return(0);
450: }
452: /*@
453: PCMatApply - Applies the preconditioner to multiple vectors stored as a MATDENSE. Like PCApply(), Y and X must be different matrices.
455: Collective on PC
457: Input Parameters:
458: + pc - the preconditioner context
459: - X - block of input vectors
461: Output Parameter:
462: . Y - block of output vectors
464: Level: developer
466: .seealso: PCApply(), KSPMatSolve()
467: @*/
468: PetscErrorCode PCMatApply(PC pc,Mat X,Mat Y)
469: {
470: Mat A;
471: Vec cy, cx;
472: PetscInt m1, M1, m2, M2, n1, N1, n2, N2, m3, M3, n3, N3;
473: PetscBool match;
482: if (Y == X) SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_IDN, "Y and X must be different matrices");
483: PCGetOperators(pc, NULL, &A);
484: MatGetLocalSize(A, &m3, &n3);
485: MatGetLocalSize(X, &m2, &n2);
486: MatGetLocalSize(Y, &m1, &n1);
487: MatGetSize(A, &M3, &N3);
488: MatGetSize(X, &M2, &N2);
489: MatGetSize(Y, &M1, &N1);
490: if (n1 != n2 || N1 != N2) SETERRQ4(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Incompatible number of columns between block of input vectors (n,N) = (%D,%D) and block of output vectors (n,N) = (%D,%D)", n2, N2, n1, N1);
491: if (m2 != m3 || M2 != M3) SETERRQ6(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Incompatible layout between block of input vectors (m,M) = (%D,%D) and Pmat (m,M)x(n,N) = (%D,%D)x(%D,%D)", m2, M2, m3, M3, n3, N3);
492: if (m1 != n3 || M1 != N3) SETERRQ6(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Incompatible layout between block of output vectors (m,M) = (%D,%D) and Pmat (m,M)x(n,N) = (%D,%D)x(%D,%D)", m1, M1, m3, M3, n3, N3);
493: PetscObjectBaseTypeCompareAny((PetscObject)Y, &match, MATSEQDENSE, MATMPIDENSE, "");
494: if (!match) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Provided block of output vectors not stored in a dense Mat");
495: PetscObjectBaseTypeCompareAny((PetscObject)X, &match, MATSEQDENSE, MATMPIDENSE, "");
496: if (!match) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Provided block of input vectors not stored in a dense Mat");
497: PCSetUp(pc);
498: if (pc->ops->matapply) {
499: PetscLogEventBegin(PC_MatApply, pc, X, Y, 0);
500: (*pc->ops->matapply)(pc, X, Y);
501: PetscLogEventEnd(PC_MatApply, pc, X, Y, 0);
502: } else {
503: PetscInfo1(pc, "PC type %s applying column by column\n", ((PetscObject)pc)->type_name);
504: for (n1 = 0; n1 < N1; ++n1) {
505: MatDenseGetColumnVecRead(X, n1, &cx);
506: MatDenseGetColumnVecWrite(Y, n1, &cy);
507: PCApply(pc, cx, cy);
508: MatDenseRestoreColumnVecWrite(Y, n1, &cy);
509: MatDenseRestoreColumnVecRead(X, n1, &cx);
510: }
511: }
512: return(0);
513: }
515: /*@
516: PCApplySymmetricLeft - Applies the left part of a symmetric preconditioner to a vector.
518: Collective on PC
520: Input Parameters:
521: + pc - the preconditioner context
522: - x - input vector
524: Output Parameter:
525: . y - output vector
527: Notes:
528: Currently, this routine is implemented only for PCICC and PCJACOBI preconditioners.
530: Level: developer
532: .seealso: PCApply(), PCApplySymmetricRight()
533: @*/
534: PetscErrorCode PCApplySymmetricLeft(PC pc,Vec x,Vec y)
535: {
542: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
543: if (pc->erroriffailure) {VecValidValues(x,2,PETSC_TRUE);}
544: PCSetUp(pc);
545: if (!pc->ops->applysymmetricleft) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have left symmetric apply");
546: VecLockReadPush(x);
547: PetscLogEventBegin(PC_ApplySymmetricLeft,pc,x,y,0);
548: (*pc->ops->applysymmetricleft)(pc,x,y);
549: PetscLogEventEnd(PC_ApplySymmetricLeft,pc,x,y,0);
550: VecLockReadPop(x);
551: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
552: return(0);
553: }
555: /*@
556: PCApplySymmetricRight - Applies the right part of a symmetric preconditioner to a vector.
558: Collective on PC
560: Input Parameters:
561: + pc - the preconditioner context
562: - x - input vector
564: Output Parameter:
565: . y - output vector
567: Level: developer
569: Notes:
570: Currently, this routine is implemented only for PCICC and PCJACOBI preconditioners.
572: .seealso: PCApply(), PCApplySymmetricLeft()
573: @*/
574: PetscErrorCode PCApplySymmetricRight(PC pc,Vec x,Vec y)
575: {
582: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
583: if (pc->erroriffailure) {VecValidValues(x,2,PETSC_TRUE);}
584: PCSetUp(pc);
585: if (!pc->ops->applysymmetricright) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have left symmetric apply");
586: VecLockReadPush(x);
587: PetscLogEventBegin(PC_ApplySymmetricRight,pc,x,y,0);
588: (*pc->ops->applysymmetricright)(pc,x,y);
589: PetscLogEventEnd(PC_ApplySymmetricRight,pc,x,y,0);
590: VecLockReadPop(x);
591: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
592: return(0);
593: }
595: /*@
596: PCApplyTranspose - Applies the transpose of preconditioner to a vector.
598: Collective on PC
600: Input Parameters:
601: + pc - the preconditioner context
602: - x - input vector
604: Output Parameter:
605: . y - output vector
607: Notes:
608: For complex numbers this applies the non-Hermitian transpose.
610: Developer Notes:
611: We need to implement a PCApplyHermitianTranspose()
613: Level: developer
615: .seealso: PCApply(), PCApplyBAorAB(), PCApplyBAorABTranspose(), PCApplyTransposeExists()
616: @*/
617: PetscErrorCode PCApplyTranspose(PC pc,Vec x,Vec y)
618: {
625: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
626: if (pc->erroriffailure) {VecValidValues(x,2,PETSC_TRUE);}
627: PCSetUp(pc);
628: if (!pc->ops->applytranspose) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have apply transpose");
629: VecLockReadPush(x);
630: PetscLogEventBegin(PC_Apply,pc,x,y,0);
631: (*pc->ops->applytranspose)(pc,x,y);
632: PetscLogEventEnd(PC_Apply,pc,x,y,0);
633: VecLockReadPop(x);
634: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
635: return(0);
636: }
638: /*@
639: PCApplyTransposeExists - Test whether the preconditioner has a transpose apply operation
641: Collective on PC
643: Input Parameters:
644: . pc - the preconditioner context
646: Output Parameter:
647: . flg - PETSC_TRUE if a transpose operation is defined
649: Level: developer
651: .seealso: PCApplyTranspose()
652: @*/
653: PetscErrorCode PCApplyTransposeExists(PC pc,PetscBool *flg)
654: {
658: if (pc->ops->applytranspose) *flg = PETSC_TRUE;
659: else *flg = PETSC_FALSE;
660: return(0);
661: }
663: /*@
664: PCApplyBAorAB - Applies the preconditioner and operator to a vector. y = B*A*x or y = A*B*x.
666: Collective on PC
668: Input Parameters:
669: + pc - the preconditioner context
670: . side - indicates the preconditioner side, one of PC_LEFT, PC_RIGHT, or PC_SYMMETRIC
671: . x - input vector
672: - work - work vector
674: Output Parameter:
675: . y - output vector
677: Level: developer
679: Notes:
680: If the PC has had PCSetDiagonalScale() set then D M A D^{-1} for left preconditioning or D A M D^{-1} is actually applied. Note that the
681: specific KSPSolve() method must also be written to handle the post-solve "correction" for the diagonal scaling.
683: .seealso: PCApply(), PCApplyTranspose(), PCApplyBAorABTranspose()
684: @*/
685: PetscErrorCode PCApplyBAorAB(PC pc,PCSide side,Vec x,Vec y,Vec work)
686: {
698: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
699: if (side != PC_LEFT && side != PC_SYMMETRIC && side != PC_RIGHT) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Side must be right, left, or symmetric");
700: if (pc->diagonalscale && side == PC_SYMMETRIC) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot include diagonal scaling with symmetric preconditioner application");
701: if (pc->erroriffailure) {VecValidValues(x,3,PETSC_TRUE);}
703: PCSetUp(pc);
704: if (pc->diagonalscale) {
705: if (pc->ops->applyBA) {
706: Vec work2; /* this is expensive, but to fix requires a second work vector argument to PCApplyBAorAB() */
707: VecDuplicate(x,&work2);
708: PCDiagonalScaleRight(pc,x,work2);
709: (*pc->ops->applyBA)(pc,side,work2,y,work);
710: PCDiagonalScaleLeft(pc,y,y);
711: VecDestroy(&work2);
712: } else if (side == PC_RIGHT) {
713: PCDiagonalScaleRight(pc,x,y);
714: PCApply(pc,y,work);
715: MatMult(pc->mat,work,y);
716: PCDiagonalScaleLeft(pc,y,y);
717: } else if (side == PC_LEFT) {
718: PCDiagonalScaleRight(pc,x,y);
719: MatMult(pc->mat,y,work);
720: PCApply(pc,work,y);
721: PCDiagonalScaleLeft(pc,y,y);
722: } else if (side == PC_SYMMETRIC) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot provide diagonal scaling with symmetric application of preconditioner");
723: } else {
724: if (pc->ops->applyBA) {
725: (*pc->ops->applyBA)(pc,side,x,y,work);
726: } else if (side == PC_RIGHT) {
727: PCApply(pc,x,work);
728: MatMult(pc->mat,work,y);
729: } else if (side == PC_LEFT) {
730: MatMult(pc->mat,x,work);
731: PCApply(pc,work,y);
732: } else if (side == PC_SYMMETRIC) {
733: /* There's an extra copy here; maybe should provide 2 work vectors instead? */
734: PCApplySymmetricRight(pc,x,work);
735: MatMult(pc->mat,work,y);
736: VecCopy(y,work);
737: PCApplySymmetricLeft(pc,work,y);
738: }
739: }
740: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
741: return(0);
742: }
744: /*@
745: PCApplyBAorABTranspose - Applies the transpose of the preconditioner
746: and operator to a vector. That is, applies tr(B) * tr(A) with left preconditioning,
747: NOT tr(B*A) = tr(A)*tr(B).
749: Collective on PC
751: Input Parameters:
752: + pc - the preconditioner context
753: . side - indicates the preconditioner side, one of PC_LEFT, PC_RIGHT, or PC_SYMMETRIC
754: . x - input vector
755: - work - work vector
757: Output Parameter:
758: . y - output vector
760: Notes:
761: this routine is used internally so that the same Krylov code can be used to solve A x = b and A' x = b, with a preconditioner
762: defined by B'. This is why this has the funny form that it computes tr(B) * tr(A)
764: Level: developer
766: .seealso: PCApply(), PCApplyTranspose(), PCApplyBAorAB()
767: @*/
768: PetscErrorCode PCApplyBAorABTranspose(PC pc,PCSide side,Vec x,Vec y,Vec work)
769: {
777: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
778: if (pc->erroriffailure) {VecValidValues(x,3,PETSC_TRUE);}
779: if (pc->ops->applyBAtranspose) {
780: (*pc->ops->applyBAtranspose)(pc,side,x,y,work);
781: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
782: return(0);
783: }
784: if (side != PC_LEFT && side != PC_RIGHT) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Side must be right or left");
786: PCSetUp(pc);
787: if (side == PC_RIGHT) {
788: PCApplyTranspose(pc,x,work);
789: MatMultTranspose(pc->mat,work,y);
790: } else if (side == PC_LEFT) {
791: MatMultTranspose(pc->mat,x,work);
792: PCApplyTranspose(pc,work,y);
793: }
794: /* add support for PC_SYMMETRIC */
795: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
796: return(0);
797: }
799: /* -------------------------------------------------------------------------------*/
801: /*@
802: PCApplyRichardsonExists - Determines whether a particular preconditioner has a
803: built-in fast application of Richardson's method.
805: Not Collective
807: Input Parameter:
808: . pc - the preconditioner
810: Output Parameter:
811: . exists - PETSC_TRUE or PETSC_FALSE
813: Level: developer
815: .seealso: PCApplyRichardson()
816: @*/
817: PetscErrorCode PCApplyRichardsonExists(PC pc,PetscBool *exists)
818: {
822: if (pc->ops->applyrichardson) *exists = PETSC_TRUE;
823: else *exists = PETSC_FALSE;
824: return(0);
825: }
827: /*@
828: PCApplyRichardson - Applies several steps of Richardson iteration with
829: the particular preconditioner. This routine is usually used by the
830: Krylov solvers and not the application code directly.
832: Collective on PC
834: Input Parameters:
835: + pc - the preconditioner context
836: . b - the right hand side
837: . w - one work vector
838: . rtol - relative decrease in residual norm convergence criteria
839: . abstol - absolute residual norm convergence criteria
840: . dtol - divergence residual norm increase criteria
841: . its - the number of iterations to apply.
842: - guesszero - if the input x contains nonzero initial guess
844: Output Parameters:
845: + outits - number of iterations actually used (for SOR this always equals its)
846: . reason - the reason the apply terminated
847: - y - the solution (also contains initial guess if guesszero is PETSC_FALSE
849: Notes:
850: Most preconditioners do not support this function. Use the command
851: PCApplyRichardsonExists() to determine if one does.
853: Except for the multigrid PC this routine ignores the convergence tolerances
854: and always runs for the number of iterations
856: Level: developer
858: .seealso: PCApplyRichardsonExists()
859: @*/
860: PetscErrorCode PCApplyRichardson(PC pc,Vec b,Vec y,Vec w,PetscReal rtol,PetscReal abstol, PetscReal dtol,PetscInt its,PetscBool guesszero,PetscInt *outits,PCRichardsonConvergedReason *reason)
861: {
869: if (b == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"b and y must be different vectors");
870: PCSetUp(pc);
871: if (!pc->ops->applyrichardson) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have apply richardson");
872: (*pc->ops->applyrichardson)(pc,b,y,w,rtol,abstol,dtol,its,guesszero,outits,reason);
873: return(0);
874: }
876: /*@
877: PCSetFailedReason - Sets the reason a PCSetUp() failed or PC_NOERROR if it did not fail
879: Logically Collective on PC
881: Input Parameters:
882: + pc - the preconditioner context
883: - reason - the reason it failedx
885: Level: advanced
887: .seealso: PCCreate(), PCApply(), PCDestroy(), PCFailedReason
888: @*/
889: PetscErrorCode PCSetFailedReason(PC pc,PCFailedReason reason)
890: {
892: pc->failedreason = reason;
893: return(0);
894: }
896: /*@
897: PCGetFailedReason - Gets the reason a PCSetUp() failed or PC_NOERROR if it did not fail
899: Logically Collective on PC
901: Input Parameter:
902: . pc - the preconditioner context
904: Output Parameter:
905: . reason - the reason it failed
907: Level: advanced
909: Notes: This is the maximum over reason over all ranks in the PC communicator. It is only valid after
910: a call KSPCheckDot() or KSPCheckNorm() inside a KSPSolve(). It is not valid immediately after a PCSetUp()
911: or PCApply(), then use PCGetFailedReasonRank()
913: .seealso: PCCreate(), PCApply(), PCDestroy(), PCGetFailedReasonRank(), PCSetFailedReason()
914: @*/
915: PetscErrorCode PCGetFailedReason(PC pc,PCFailedReason *reason)
916: {
918: if (pc->setupcalled < 0) *reason = (PCFailedReason)pc->setupcalled;
919: else *reason = pc->failedreason;
920: return(0);
921: }
923: /*@
924: PCGetFailedReasonRank - Gets the reason a PCSetUp() failed or PC_NOERROR if it did not fail on this MPI rank
926: Not Collective on PC
928: Input Parameter:
929: . pc - the preconditioner context
931: Output Parameter:
932: . reason - the reason it failed
934: Notes:
935: Different ranks may have different reasons or no reason, see PCGetFailedReason()
937: Level: advanced
939: .seealso: PCCreate(), PCApply(), PCDestroy(), PCGetFailedReason(), PCSetFailedReason()
940: @*/
941: PetscErrorCode PCGetFailedReasonRank(PC pc,PCFailedReason *reason)
942: {
944: if (pc->setupcalled < 0) *reason = (PCFailedReason)pc->setupcalled;
945: else *reason = pc->failedreason;
946: return(0);
947: }
949: /* Next line needed to deactivate KSP_Solve logging */
950: #include <petsc/private/kspimpl.h>
952: /*
953: a setupcall of 0 indicates never setup,
954: 1 indicates has been previously setup
955: -1 indicates a PCSetUp() was attempted and failed
956: */
957: /*@
958: PCSetUp - Prepares for the use of a preconditioner.
960: Collective on PC
962: Input Parameter:
963: . pc - the preconditioner context
965: Level: developer
967: .seealso: PCCreate(), PCApply(), PCDestroy()
968: @*/
969: PetscErrorCode PCSetUp(PC pc)
970: {
971: PetscErrorCode ierr;
972: const char *def;
973: PetscObjectState matstate, matnonzerostate;
977: if (!pc->mat) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Matrix must be set first");
979: if (pc->setupcalled && pc->reusepreconditioner) {
980: PetscInfo(pc,"Leaving PC with identical preconditioner since reuse preconditioner is set\n");
981: return(0);
982: }
984: PetscObjectStateGet((PetscObject)pc->pmat,&matstate);
985: MatGetNonzeroState(pc->pmat,&matnonzerostate);
986: if (!pc->setupcalled) {
987: PetscInfo(pc,"Setting up PC for first time\n");
988: pc->flag = DIFFERENT_NONZERO_PATTERN;
989: } else if (matstate == pc->matstate) {
990: PetscInfo(pc,"Leaving PC with identical preconditioner since operator is unchanged\n");
991: return(0);
992: } else {
993: if (matnonzerostate > pc->matnonzerostate) {
994: PetscInfo(pc,"Setting up PC with different nonzero pattern\n");
995: pc->flag = DIFFERENT_NONZERO_PATTERN;
996: } else {
997: PetscInfo(pc,"Setting up PC with same nonzero pattern\n");
998: pc->flag = SAME_NONZERO_PATTERN;
999: }
1000: }
1001: pc->matstate = matstate;
1002: pc->matnonzerostate = matnonzerostate;
1004: if (!((PetscObject)pc)->type_name) {
1005: PCGetDefaultType_Private(pc,&def);
1006: PCSetType(pc,def);
1007: }
1009: MatSetErrorIfFailure(pc->pmat,pc->erroriffailure);
1010: MatSetErrorIfFailure(pc->mat,pc->erroriffailure);
1011: PetscLogEventBegin(PC_SetUp,pc,0,0,0);
1012: if (pc->ops->setup) {
1013: /* do not log solves and applications of preconditioners while constructing preconditioners; perhaps they should be logged separately from the regular solves */
1014: PetscLogEventDeactivatePush(KSP_Solve);
1015: PetscLogEventDeactivatePush(PC_Apply);
1016: (*pc->ops->setup)(pc);
1017: PetscLogEventDeactivatePop(KSP_Solve);
1018: PetscLogEventDeactivatePop(PC_Apply);
1019: }
1020: PetscLogEventEnd(PC_SetUp,pc,0,0,0);
1021: if (!pc->setupcalled) pc->setupcalled = 1;
1022: return(0);
1023: }
1025: /*@
1026: PCSetUpOnBlocks - Sets up the preconditioner for each block in
1027: the block Jacobi, block Gauss-Seidel, and overlapping Schwarz
1028: methods.
1030: Collective on PC
1032: Input Parameters:
1033: . pc - the preconditioner context
1035: Level: developer
1037: .seealso: PCCreate(), PCApply(), PCDestroy(), PCSetUp()
1038: @*/
1039: PetscErrorCode PCSetUpOnBlocks(PC pc)
1040: {
1045: if (!pc->ops->setuponblocks) return(0);
1046: PetscLogEventBegin(PC_SetUpOnBlocks,pc,0,0,0);
1047: (*pc->ops->setuponblocks)(pc);
1048: PetscLogEventEnd(PC_SetUpOnBlocks,pc,0,0,0);
1049: return(0);
1050: }
1052: /*@C
1053: PCSetModifySubMatrices - Sets a user-defined routine for modifying the
1054: submatrices that arise within certain subdomain-based preconditioners.
1055: The basic submatrices are extracted from the preconditioner matrix as
1056: usual; the user can then alter these (for example, to set different boundary
1057: conditions for each submatrix) before they are used for the local solves.
1059: Logically Collective on PC
1061: Input Parameters:
1062: + pc - the preconditioner context
1063: . func - routine for modifying the submatrices
1064: - ctx - optional user-defined context (may be null)
1066: Calling sequence of func:
1067: $ func (PC pc,PetscInt nsub,IS *row,IS *col,Mat *submat,void *ctx);
1069: + row - an array of index sets that contain the global row numbers
1070: that comprise each local submatrix
1071: . col - an array of index sets that contain the global column numbers
1072: that comprise each local submatrix
1073: . submat - array of local submatrices
1074: - ctx - optional user-defined context for private data for the
1075: user-defined func routine (may be null)
1077: Notes:
1078: PCSetModifySubMatrices() MUST be called before KSPSetUp() and
1079: KSPSolve().
1081: A routine set by PCSetModifySubMatrices() is currently called within
1082: the block Jacobi (PCBJACOBI) and additive Schwarz (PCASM)
1083: preconditioners. All other preconditioners ignore this routine.
1085: Level: advanced
1087: .seealso: PCModifySubMatrices()
1088: @*/
1089: PetscErrorCode PCSetModifySubMatrices(PC pc,PetscErrorCode (*func)(PC,PetscInt,const IS[],const IS[],Mat[],void*),void *ctx)
1090: {
1093: pc->modifysubmatrices = func;
1094: pc->modifysubmatricesP = ctx;
1095: return(0);
1096: }
1098: /*@C
1099: PCModifySubMatrices - Calls an optional user-defined routine within
1100: certain preconditioners if one has been set with PCSetModifySubMatrices().
1102: Collective on PC
1104: Input Parameters:
1105: + pc - the preconditioner context
1106: . nsub - the number of local submatrices
1107: . row - an array of index sets that contain the global row numbers
1108: that comprise each local submatrix
1109: . col - an array of index sets that contain the global column numbers
1110: that comprise each local submatrix
1111: . submat - array of local submatrices
1112: - ctx - optional user-defined context for private data for the
1113: user-defined routine (may be null)
1115: Output Parameter:
1116: . submat - array of local submatrices (the entries of which may
1117: have been modified)
1119: Notes:
1120: The user should NOT generally call this routine, as it will
1121: automatically be called within certain preconditioners (currently
1122: block Jacobi, additive Schwarz) if set.
1124: The basic submatrices are extracted from the preconditioner matrix
1125: as usual; the user can then alter these (for example, to set different
1126: boundary conditions for each submatrix) before they are used for the
1127: local solves.
1129: Level: developer
1131: .seealso: PCSetModifySubMatrices()
1132: @*/
1133: PetscErrorCode PCModifySubMatrices(PC pc,PetscInt nsub,const IS row[],const IS col[],Mat submat[],void *ctx)
1134: {
1139: if (!pc->modifysubmatrices) return(0);
1140: PetscLogEventBegin(PC_ModifySubMatrices,pc,0,0,0);
1141: (*pc->modifysubmatrices)(pc,nsub,row,col,submat,ctx);
1142: PetscLogEventEnd(PC_ModifySubMatrices,pc,0,0,0);
1143: return(0);
1144: }
1146: /*@
1147: PCSetOperators - Sets the matrix associated with the linear system and
1148: a (possibly) different one associated with the preconditioner.
1150: Logically Collective on PC
1152: Input Parameters:
1153: + pc - the preconditioner context
1154: . Amat - the matrix that defines the linear system
1155: - Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
1157: Notes:
1158: Passing a NULL for Amat or Pmat removes the matrix that is currently used.
1160: If you wish to replace either Amat or Pmat but leave the other one untouched then
1161: first call KSPGetOperators() to get the one you wish to keep, call PetscObjectReference()
1162: on it and then pass it back in in your call to KSPSetOperators().
1164: More Notes about Repeated Solution of Linear Systems:
1165: PETSc does NOT reset the matrix entries of either Amat or Pmat
1166: to zero after a linear solve; the user is completely responsible for
1167: matrix assembly. See the routine MatZeroEntries() if desiring to
1168: zero all elements of a matrix.
1170: Level: intermediate
1172: .seealso: PCGetOperators(), MatZeroEntries()
1173: @*/
1174: PetscErrorCode PCSetOperators(PC pc,Mat Amat,Mat Pmat)
1175: {
1176: PetscErrorCode ierr;
1177: PetscInt m1,n1,m2,n2;
1185: if (pc->setupcalled && pc->mat && pc->pmat && Amat && Pmat) {
1186: MatGetLocalSize(Amat,&m1,&n1);
1187: MatGetLocalSize(pc->mat,&m2,&n2);
1188: if (m1 != m2 || n1 != n2) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Cannot change local size of Amat after use old sizes %D %D new sizes %D %D",m2,n2,m1,n1);
1189: MatGetLocalSize(Pmat,&m1,&n1);
1190: MatGetLocalSize(pc->pmat,&m2,&n2);
1191: if (m1 != m2 || n1 != n2) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Cannot change local size of Pmat after use old sizes %D %D new sizes %D %D",m2,n2,m1,n1);
1192: }
1194: if (Pmat != pc->pmat) {
1195: /* changing the operator that defines the preconditioner thus reneed to clear current states so new preconditioner is built */
1196: pc->matnonzerostate = -1;
1197: pc->matstate = -1;
1198: }
1200: /* reference first in case the matrices are the same */
1201: if (Amat) {PetscObjectReference((PetscObject)Amat);}
1202: MatDestroy(&pc->mat);
1203: if (Pmat) {PetscObjectReference((PetscObject)Pmat);}
1204: MatDestroy(&pc->pmat);
1205: pc->mat = Amat;
1206: pc->pmat = Pmat;
1207: return(0);
1208: }
1210: /*@
1211: PCSetReusePreconditioner - reuse the current preconditioner even if the operator in the preconditioner has changed.
1213: Logically Collective on PC
1215: Input Parameters:
1216: + pc - the preconditioner context
1217: - flag - PETSC_TRUE do not compute a new preconditioner, PETSC_FALSE do compute a new preconditioner
1219: Level: intermediate
1221: .seealso: PCGetOperators(), MatZeroEntries(), PCGetReusePreconditioner(), KSPSetReusePreconditioner()
1222: @*/
1223: PetscErrorCode PCSetReusePreconditioner(PC pc,PetscBool flag)
1224: {
1228: pc->reusepreconditioner = flag;
1229: return(0);
1230: }
1232: /*@
1233: PCGetReusePreconditioner - Determines if the PC reuses the current preconditioner even if the operator in the preconditioner has changed.
1235: Not Collective
1237: Input Parameter:
1238: . pc - the preconditioner context
1240: Output Parameter:
1241: . flag - PETSC_TRUE do not compute a new preconditioner, PETSC_FALSE do compute a new preconditioner
1243: Level: intermediate
1245: .seealso: PCGetOperators(), MatZeroEntries(), PCSetReusePreconditioner()
1246: @*/
1247: PetscErrorCode PCGetReusePreconditioner(PC pc,PetscBool *flag)
1248: {
1252: *flag = pc->reusepreconditioner;
1253: return(0);
1254: }
1256: /*@
1257: PCGetOperators - Gets the matrix associated with the linear system and
1258: possibly a different one associated with the preconditioner.
1260: Not collective, though parallel Mats are returned if the PC is parallel
1262: Input Parameter:
1263: . pc - the preconditioner context
1265: Output Parameters:
1266: + Amat - the matrix defining the linear system
1267: - Pmat - the matrix from which the preconditioner is constructed, usually the same as Amat.
1269: Level: intermediate
1271: Notes:
1272: Does not increase the reference count of the matrices, so you should not destroy them
1274: Alternative usage: If the operators have NOT been set with KSP/PCSetOperators() then the operators
1275: are created in PC and returned to the user. In this case, if both operators
1276: mat and pmat are requested, two DIFFERENT operators will be returned. If
1277: only one is requested both operators in the PC will be the same (i.e. as
1278: if one had called KSP/PCSetOperators() with the same argument for both Mats).
1279: The user must set the sizes of the returned matrices and their type etc just
1280: as if the user created them with MatCreate(). For example,
1282: $ KSP/PCGetOperators(ksp/pc,&Amat,NULL); is equivalent to
1283: $ set size, type, etc of Amat
1285: $ MatCreate(comm,&mat);
1286: $ KSP/PCSetOperators(ksp/pc,Amat,Amat);
1287: $ PetscObjectDereference((PetscObject)mat);
1288: $ set size, type, etc of Amat
1290: and
1292: $ KSP/PCGetOperators(ksp/pc,&Amat,&Pmat); is equivalent to
1293: $ set size, type, etc of Amat and Pmat
1295: $ MatCreate(comm,&Amat);
1296: $ MatCreate(comm,&Pmat);
1297: $ KSP/PCSetOperators(ksp/pc,Amat,Pmat);
1298: $ PetscObjectDereference((PetscObject)Amat);
1299: $ PetscObjectDereference((PetscObject)Pmat);
1300: $ set size, type, etc of Amat and Pmat
1302: The rational for this support is so that when creating a TS, SNES, or KSP the hierarchy
1303: of underlying objects (i.e. SNES, KSP, PC, Mat) and their livespans can be completely
1304: managed by the top most level object (i.e. the TS, SNES, or KSP). Another way to look
1305: at this is when you create a SNES you do not NEED to create a KSP and attach it to
1306: the SNES object (the SNES object manages it for you). Similarly when you create a KSP
1307: you do not need to attach a PC to it (the KSP object manages the PC object for you).
1308: Thus, why should YOU have to create the Mat and attach it to the SNES/KSP/PC, when
1309: it can be created for you?
1311: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperatorsSet()
1312: @*/
1313: PetscErrorCode PCGetOperators(PC pc,Mat *Amat,Mat *Pmat)
1314: {
1319: if (Amat) {
1320: if (!pc->mat) {
1321: if (pc->pmat && !Pmat) { /* Apmat has been set, but user did not request it, so use for Amat */
1322: pc->mat = pc->pmat;
1323: PetscObjectReference((PetscObject)pc->mat);
1324: } else { /* both Amat and Pmat are empty */
1325: MatCreate(PetscObjectComm((PetscObject)pc),&pc->mat);
1326: if (!Pmat) { /* user did NOT request Pmat, so make same as Amat */
1327: pc->pmat = pc->mat;
1328: PetscObjectReference((PetscObject)pc->pmat);
1329: }
1330: }
1331: }
1332: *Amat = pc->mat;
1333: }
1334: if (Pmat) {
1335: if (!pc->pmat) {
1336: if (pc->mat && !Amat) { /* Amat has been set but was not requested, so use for pmat */
1337: pc->pmat = pc->mat;
1338: PetscObjectReference((PetscObject)pc->pmat);
1339: } else {
1340: MatCreate(PetscObjectComm((PetscObject)pc),&pc->pmat);
1341: if (!Amat) { /* user did NOT request Amat, so make same as Pmat */
1342: pc->mat = pc->pmat;
1343: PetscObjectReference((PetscObject)pc->mat);
1344: }
1345: }
1346: }
1347: *Pmat = pc->pmat;
1348: }
1349: return(0);
1350: }
1352: /*@C
1353: PCGetOperatorsSet - Determines if the matrix associated with the linear system and
1354: possibly a different one associated with the preconditioner have been set in the PC.
1356: Not collective, though the results on all processes should be the same
1358: Input Parameter:
1359: . pc - the preconditioner context
1361: Output Parameters:
1362: + mat - the matrix associated with the linear system was set
1363: - pmat - matrix associated with the preconditioner was set, usually the same
1365: Level: intermediate
1367: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperators()
1368: @*/
1369: PetscErrorCode PCGetOperatorsSet(PC pc,PetscBool *mat,PetscBool *pmat)
1370: {
1373: if (mat) *mat = (pc->mat) ? PETSC_TRUE : PETSC_FALSE;
1374: if (pmat) *pmat = (pc->pmat) ? PETSC_TRUE : PETSC_FALSE;
1375: return(0);
1376: }
1378: /*@
1379: PCFactorGetMatrix - Gets the factored matrix from the
1380: preconditioner context. This routine is valid only for the LU,
1381: incomplete LU, Cholesky, and incomplete Cholesky methods.
1383: Not Collective on PC though Mat is parallel if PC is parallel
1385: Input Parameters:
1386: . pc - the preconditioner context
1388: Output parameters:
1389: . mat - the factored matrix
1391: Level: advanced
1393: Notes:
1394: Does not increase the reference count for the matrix so DO NOT destroy it
1396: @*/
1397: PetscErrorCode PCFactorGetMatrix(PC pc,Mat *mat)
1398: {
1404: if (pc->ops->getfactoredmatrix) {
1405: (*pc->ops->getfactoredmatrix)(pc,mat);
1406: } else SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC type does not support getting factor matrix");
1407: return(0);
1408: }
1410: /*@C
1411: PCSetOptionsPrefix - Sets the prefix used for searching for all
1412: PC options in the database.
1414: Logically Collective on PC
1416: Input Parameters:
1417: + pc - the preconditioner context
1418: - prefix - the prefix string to prepend to all PC option requests
1420: Notes:
1421: A hyphen (-) must NOT be given at the beginning of the prefix name.
1422: The first character of all runtime options is AUTOMATICALLY the
1423: hyphen.
1425: Level: advanced
1427: .seealso: PCAppendOptionsPrefix(), PCGetOptionsPrefix()
1428: @*/
1429: PetscErrorCode PCSetOptionsPrefix(PC pc,const char prefix[])
1430: {
1435: PetscObjectSetOptionsPrefix((PetscObject)pc,prefix);
1436: return(0);
1437: }
1439: /*@C
1440: PCAppendOptionsPrefix - Appends to the prefix used for searching for all
1441: PC options in the database.
1443: Logically Collective on PC
1445: Input Parameters:
1446: + pc - the preconditioner context
1447: - prefix - the prefix string to prepend to all PC option requests
1449: Notes:
1450: A hyphen (-) must NOT be given at the beginning of the prefix name.
1451: The first character of all runtime options is AUTOMATICALLY the
1452: hyphen.
1454: Level: advanced
1456: .seealso: PCSetOptionsPrefix(), PCGetOptionsPrefix()
1457: @*/
1458: PetscErrorCode PCAppendOptionsPrefix(PC pc,const char prefix[])
1459: {
1464: PetscObjectAppendOptionsPrefix((PetscObject)pc,prefix);
1465: return(0);
1466: }
1468: /*@C
1469: PCGetOptionsPrefix - Gets the prefix used for searching for all
1470: PC options in the database.
1472: Not Collective
1474: Input Parameters:
1475: . pc - the preconditioner context
1477: Output Parameters:
1478: . prefix - pointer to the prefix string used, is returned
1480: Notes:
1481: On the fortran side, the user should pass in a string 'prifix' of
1482: sufficient length to hold the prefix.
1484: Level: advanced
1486: .seealso: PCSetOptionsPrefix(), PCAppendOptionsPrefix()
1487: @*/
1488: PetscErrorCode PCGetOptionsPrefix(PC pc,const char *prefix[])
1489: {
1495: PetscObjectGetOptionsPrefix((PetscObject)pc,prefix);
1496: return(0);
1497: }
1499: /*
1500: Indicates the right hand side will be changed by KSPSolve(), this occurs for a few
1501: preconditioners including BDDC and Eisentat that transform the equations before applying
1502: the Krylov methods
1503: */
1504: PETSC_INTERN PetscErrorCode PCPreSolveChangeRHS(PC pc,PetscBool *change)
1505: {
1511: *change = PETSC_FALSE;
1512: PetscTryMethod(pc,"PCPreSolveChangeRHS_C",(PC,PetscBool*),(pc,change));
1513: return(0);
1514: }
1516: /*@
1517: PCPreSolve - Optional pre-solve phase, intended for any
1518: preconditioner-specific actions that must be performed before
1519: the iterative solve itself.
1521: Collective on PC
1523: Input Parameters:
1524: + pc - the preconditioner context
1525: - ksp - the Krylov subspace context
1527: Level: developer
1529: Sample of Usage:
1530: .vb
1531: PCPreSolve(pc,ksp);
1532: KSPSolve(ksp,b,x);
1533: PCPostSolve(pc,ksp);
1534: .ve
1536: Notes:
1537: The pre-solve phase is distinct from the PCSetUp() phase.
1539: KSPSolve() calls this directly, so is rarely called by the user.
1541: .seealso: PCPostSolve()
1542: @*/
1543: PetscErrorCode PCPreSolve(PC pc,KSP ksp)
1544: {
1546: Vec x,rhs;
1551: pc->presolvedone++;
1552: if (pc->presolvedone > 2) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot embed PCPreSolve() more than twice");
1553: KSPGetSolution(ksp,&x);
1554: KSPGetRhs(ksp,&rhs);
1556: if (pc->ops->presolve) {
1557: (*pc->ops->presolve)(pc,ksp,rhs,x);
1558: } else if (pc->presolve) {
1559: (pc->presolve)(pc,ksp);
1560: }
1561: return(0);
1562: }
1564: /*@C
1565: PCSetPreSolve - Sets function PCPreSolve() which is intended for any
1566: preconditioner-specific actions that must be performed before
1567: the iterative solve itself.
1569: Logically Collective on pc
1571: Input Parameters:
1572: + pc - the preconditioner object
1573: - presolve - the function to call before the solve
1575: Calling sequence of presolve:
1576: $ func(PC pc,KSP ksp)
1578: + pc - the PC context
1579: - ksp - the KSP context
1581: Level: developer
1583: .seealso: PC, PCSetUp(), PCPreSolve()
1584: @*/
1585: PetscErrorCode PCSetPreSolve(PC pc,PetscErrorCode (*presolve)(PC,KSP))
1586: {
1589: pc->presolve = presolve;
1590: return(0);
1591: }
1593: /*@
1594: PCPostSolve - Optional post-solve phase, intended for any
1595: preconditioner-specific actions that must be performed after
1596: the iterative solve itself.
1598: Collective on PC
1600: Input Parameters:
1601: + pc - the preconditioner context
1602: - ksp - the Krylov subspace context
1604: Sample of Usage:
1605: .vb
1606: PCPreSolve(pc,ksp);
1607: KSPSolve(ksp,b,x);
1608: PCPostSolve(pc,ksp);
1609: .ve
1611: Note:
1612: KSPSolve() calls this routine directly, so it is rarely called by the user.
1614: Level: developer
1616: .seealso: PCPreSolve(), KSPSolve()
1617: @*/
1618: PetscErrorCode PCPostSolve(PC pc,KSP ksp)
1619: {
1621: Vec x,rhs;
1626: pc->presolvedone--;
1627: KSPGetSolution(ksp,&x);
1628: KSPGetRhs(ksp,&rhs);
1629: if (pc->ops->postsolve) {
1630: (*pc->ops->postsolve)(pc,ksp,rhs,x);
1631: }
1632: return(0);
1633: }
1635: /*@C
1636: PCLoad - Loads a PC that has been stored in binary with PCView().
1638: Collective on PetscViewer
1640: Input Parameters:
1641: + newdm - the newly loaded PC, this needs to have been created with PCCreate() or
1642: some related function before a call to PCLoad().
1643: - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()
1645: Level: intermediate
1647: Notes:
1648: The type is determined by the data in the file, any type set into the PC before this call is ignored.
1650: Notes for advanced users:
1651: Most users should not need to know the details of the binary storage
1652: format, since PCLoad() and PCView() completely hide these details.
1653: But for anyone who's interested, the standard binary matrix storage
1654: format is
1655: .vb
1656: has not yet been determined
1657: .ve
1659: .seealso: PetscViewerBinaryOpen(), PCView(), MatLoad(), VecLoad()
1660: @*/
1661: PetscErrorCode PCLoad(PC newdm, PetscViewer viewer)
1662: {
1664: PetscBool isbinary;
1665: PetscInt classid;
1666: char type[256];
1671: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
1672: if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1674: PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
1675: if (classid != PC_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)newdm),PETSC_ERR_ARG_WRONG,"Not PC next in file");
1676: PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
1677: PCSetType(newdm, type);
1678: if (newdm->ops->load) {
1679: (*newdm->ops->load)(newdm,viewer);
1680: }
1681: return(0);
1682: }
1684: #include <petscdraw.h>
1685: #if defined(PETSC_HAVE_SAWS)
1686: #include <petscviewersaws.h>
1687: #endif
1689: /*@C
1690: PCViewFromOptions - View from Options
1692: Collective on PC
1694: Input Parameters:
1695: + A - the PC context
1696: . obj - Optional object
1697: - name - command line option
1699: Level: intermediate
1700: .seealso: PC, PCView, PetscObjectViewFromOptions(), PCCreate()
1701: @*/
1702: PetscErrorCode PCViewFromOptions(PC A,PetscObject obj,const char name[])
1703: {
1708: PetscObjectViewFromOptions((PetscObject)A,obj,name);
1709: return(0);
1710: }
1712: /*@C
1713: PCView - Prints the PC data structure.
1715: Collective on PC
1717: Input Parameters:
1718: + PC - the PC context
1719: - viewer - optional visualization context
1721: Note:
1722: The available visualization contexts include
1723: + PETSC_VIEWER_STDOUT_SELF - standard output (default)
1724: - PETSC_VIEWER_STDOUT_WORLD - synchronized standard
1725: output where only the first processor opens
1726: the file. All other processors send their
1727: data to the first processor to print.
1729: The user can open an alternative visualization contexts with
1730: PetscViewerASCIIOpen() (output to a specified file).
1732: Level: developer
1734: .seealso: KSPView(), PetscViewerASCIIOpen()
1735: @*/
1736: PetscErrorCode PCView(PC pc,PetscViewer viewer)
1737: {
1738: PCType cstr;
1740: PetscBool iascii,isstring,isbinary,isdraw;
1741: #if defined(PETSC_HAVE_SAWS)
1742: PetscBool issaws;
1743: #endif
1747: if (!viewer) {
1748: PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)pc),&viewer);
1749: }
1753: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
1754: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
1755: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
1756: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
1757: #if defined(PETSC_HAVE_SAWS)
1758: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
1759: #endif
1761: if (iascii) {
1762: PetscObjectPrintClassNamePrefixType((PetscObject)pc,viewer);
1763: if (!pc->setupcalled) {
1764: PetscViewerASCIIPrintf(viewer," PC has not been set up so information may be incomplete\n");
1765: }
1766: if (pc->ops->view) {
1767: PetscViewerASCIIPushTab(viewer);
1768: (*pc->ops->view)(pc,viewer);
1769: PetscViewerASCIIPopTab(viewer);
1770: }
1771: if (pc->mat) {
1772: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO);
1773: if (pc->pmat == pc->mat) {
1774: PetscViewerASCIIPrintf(viewer," linear system matrix = precond matrix:\n");
1775: PetscViewerASCIIPushTab(viewer);
1776: MatView(pc->mat,viewer);
1777: PetscViewerASCIIPopTab(viewer);
1778: } else {
1779: if (pc->pmat) {
1780: PetscViewerASCIIPrintf(viewer," linear system matrix followed by preconditioner matrix:\n");
1781: } else {
1782: PetscViewerASCIIPrintf(viewer," linear system matrix:\n");
1783: }
1784: PetscViewerASCIIPushTab(viewer);
1785: MatView(pc->mat,viewer);
1786: if (pc->pmat) {MatView(pc->pmat,viewer);}
1787: PetscViewerASCIIPopTab(viewer);
1788: }
1789: PetscViewerPopFormat(viewer);
1790: }
1791: } else if (isstring) {
1792: PCGetType(pc,&cstr);
1793: PetscViewerStringSPrintf(viewer," PCType: %-7.7s",cstr);
1794: if (pc->ops->view) {(*pc->ops->view)(pc,viewer);}
1795: if (pc->mat) {MatView(pc->mat,viewer);}
1796: if (pc->pmat && pc->pmat != pc->mat) {MatView(pc->pmat,viewer);}
1797: } else if (isbinary) {
1798: PetscInt classid = PC_FILE_CLASSID;
1799: MPI_Comm comm;
1800: PetscMPIInt rank;
1801: char type[256];
1803: PetscObjectGetComm((PetscObject)pc,&comm);
1804: MPI_Comm_rank(comm,&rank);
1805: if (rank == 0) {
1806: PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT);
1807: PetscStrncpy(type,((PetscObject)pc)->type_name,256);
1808: PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR);
1809: }
1810: if (pc->ops->view) {
1811: (*pc->ops->view)(pc,viewer);
1812: }
1813: } else if (isdraw) {
1814: PetscDraw draw;
1815: char str[25];
1816: PetscReal x,y,bottom,h;
1817: PetscInt n;
1819: PetscViewerDrawGetDraw(viewer,0,&draw);
1820: PetscDrawGetCurrentPoint(draw,&x,&y);
1821: if (pc->mat) {
1822: MatGetSize(pc->mat,&n,NULL);
1823: PetscSNPrintf(str,25,"PC: %s (%D)",((PetscObject)pc)->type_name,n);
1824: } else {
1825: PetscSNPrintf(str,25,"PC: %s",((PetscObject)pc)->type_name);
1826: }
1827: PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);
1828: bottom = y - h;
1829: PetscDrawPushCurrentPoint(draw,x,bottom);
1830: if (pc->ops->view) {
1831: (*pc->ops->view)(pc,viewer);
1832: }
1833: PetscDrawPopCurrentPoint(draw);
1834: #if defined(PETSC_HAVE_SAWS)
1835: } else if (issaws) {
1836: PetscMPIInt rank;
1838: PetscObjectName((PetscObject)pc);
1839: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
1840: if (!((PetscObject)pc)->amsmem && rank == 0) {
1841: PetscObjectViewSAWs((PetscObject)pc,viewer);
1842: }
1843: if (pc->mat) {MatView(pc->mat,viewer);}
1844: if (pc->pmat && pc->pmat != pc->mat) {MatView(pc->pmat,viewer);}
1845: #endif
1846: }
1847: return(0);
1848: }
1850: /*@C
1851: PCRegister - Adds a method to the preconditioner package.
1853: Not collective
1855: Input Parameters:
1856: + name_solver - name of a new user-defined solver
1857: - routine_create - routine to create method context
1859: Notes:
1860: PCRegister() may be called multiple times to add several user-defined preconditioners.
1862: Sample usage:
1863: .vb
1864: PCRegister("my_solver", MySolverCreate);
1865: .ve
1867: Then, your solver can be chosen with the procedural interface via
1868: $ PCSetType(pc,"my_solver")
1869: or at runtime via the option
1870: $ -pc_type my_solver
1872: Level: advanced
1874: .seealso: PCRegisterAll()
1875: @*/
1876: PetscErrorCode PCRegister(const char sname[],PetscErrorCode (*function)(PC))
1877: {
1881: PCInitializePackage();
1882: PetscFunctionListAdd(&PCList,sname,function);
1883: return(0);
1884: }
1886: static PetscErrorCode MatMult_PC(Mat A,Vec X,Vec Y)
1887: {
1888: PC pc;
1892: MatShellGetContext(A,&pc);
1893: PCApply(pc,X,Y);
1894: return(0);
1895: }
1897: /*@
1898: PCComputeOperator - Computes the explicit preconditioned operator.
1900: Collective on PC
1902: Input Parameters:
1903: + pc - the preconditioner object
1904: - mattype - the matrix type to be used for the operator
1906: Output Parameter:
1907: . mat - the explicit preconditioned operator
1909: Notes:
1910: This computation is done by applying the operators to columns of the identity matrix.
1911: This routine is costly in general, and is recommended for use only with relatively small systems.
1912: Currently, this routine uses a dense matrix format when mattype == NULL
1914: Level: advanced
1916: .seealso: KSPComputeOperator(), MatType
1918: @*/
1919: PetscErrorCode PCComputeOperator(PC pc,MatType mattype,Mat *mat)
1920: {
1922: PetscInt N,M,m,n;
1923: Mat A,Apc;
1928: PCGetOperators(pc,&A,NULL);
1929: MatGetLocalSize(A,&m,&n);
1930: MatGetSize(A,&M,&N);
1931: MatCreateShell(PetscObjectComm((PetscObject)pc),m,n,M,N,pc,&Apc);
1932: MatShellSetOperation(Apc,MATOP_MULT,(void (*)(void))MatMult_PC);
1933: MatComputeOperator(Apc,mattype,mat);
1934: MatDestroy(&Apc);
1935: return(0);
1936: }
1938: /*@
1939: PCSetCoordinates - sets the coordinates of all the nodes on the local process
1941: Collective on PC
1943: Input Parameters:
1944: + pc - the solver context
1945: . dim - the dimension of the coordinates 1, 2, or 3
1946: . nloc - the blocked size of the coordinates array
1947: - coords - the coordinates array
1949: Level: intermediate
1951: Notes:
1952: coords is an array of the dim coordinates for the nodes on
1953: the local processor, of size dim*nloc.
1954: If there are 108 equation on a processor
1955: for a displacement finite element discretization of elasticity (so
1956: that there are nloc = 36 = 108/3 nodes) then the array must have 108
1957: double precision values (ie, 3 * 36). These x y z coordinates
1958: should be ordered for nodes 0 to N-1 like so: [ 0.x, 0.y, 0.z, 1.x,
1959: ... , N-1.z ].
1961: .seealso: MatSetNearNullSpace()
1962: @*/
1963: PetscErrorCode PCSetCoordinates(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[])
1964: {
1970: PetscTryMethod(pc,"PCSetCoordinates_C",(PC,PetscInt,PetscInt,PetscReal*),(pc,dim,nloc,coords));
1971: return(0);
1972: }
1974: /*@
1975: PCGetInterpolations - Gets interpolation matrices for all levels (except level 0)
1977: Logically Collective on PC
1979: Input Parameter:
1980: . pc - the precondition context
1982: Output Parameters:
1983: + num_levels - the number of levels
1984: - interpolations - the interpolation matrices (size of num_levels-1)
1986: Level: advanced
1988: .keywords: MG, GAMG, BoomerAMG, multigrid, interpolation, level
1990: .seealso: PCMGGetRestriction(), PCMGSetInterpolation(), PCMGGetInterpolation(), PCGetCoarseOperators()
1991: @*/
1992: PetscErrorCode PCGetInterpolations(PC pc,PetscInt *num_levels,Mat *interpolations[])
1993: {
2000: PetscUseMethod(pc,"PCGetInterpolations_C",(PC,PetscInt*,Mat*[]),(pc,num_levels,interpolations));
2001: return(0);
2002: }
2004: /*@
2005: PCGetCoarseOperators - Gets coarse operator matrices for all levels (except the finest level)
2007: Logically Collective on PC
2009: Input Parameter:
2010: . pc - the precondition context
2012: Output Parameters:
2013: + num_levels - the number of levels
2014: - coarseOperators - the coarse operator matrices (size of num_levels-1)
2016: Level: advanced
2018: .keywords: MG, GAMG, BoomerAMG, get, multigrid, interpolation, level
2020: .seealso: PCMGGetRestriction(), PCMGSetInterpolation(), PCMGGetRScale(), PCMGGetInterpolation(), PCGetInterpolations()
2021: @*/
2022: PetscErrorCode PCGetCoarseOperators(PC pc,PetscInt *num_levels,Mat *coarseOperators[])
2023: {
2030: PetscUseMethod(pc,"PCGetCoarseOperators_C",(PC,PetscInt*,Mat*[]),(pc,num_levels,coarseOperators));
2031: return(0);
2032: }