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
761: Notes:
762: 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
763: defined by B'. This is why this has the funny form that it computes tr(B) * tr(A)
765: Level: developer
767: .seealso: PCApply(), PCApplyTranspose(), PCApplyBAorAB()
768: @*/
769: PetscErrorCode PCApplyBAorABTranspose(PC pc,PCSide side,Vec x,Vec y,Vec work)
770: {
778: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
779: if (pc->erroriffailure) {VecValidValues(x,3,PETSC_TRUE);}
780: if (pc->ops->applyBAtranspose) {
781: (*pc->ops->applyBAtranspose)(pc,side,x,y,work);
782: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
783: return(0);
784: }
785: if (side != PC_LEFT && side != PC_RIGHT) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Side must be right or left");
787: PCSetUp(pc);
788: if (side == PC_RIGHT) {
789: PCApplyTranspose(pc,x,work);
790: MatMultTranspose(pc->mat,work,y);
791: } else if (side == PC_LEFT) {
792: MatMultTranspose(pc->mat,x,work);
793: PCApplyTranspose(pc,work,y);
794: }
795: /* add support for PC_SYMMETRIC */
796: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
797: return(0);
798: }
800: /* -------------------------------------------------------------------------------*/
802: /*@
803: PCApplyRichardsonExists - Determines whether a particular preconditioner has a
804: built-in fast application of Richardson's method.
806: Not Collective
808: Input Parameter:
809: . pc - the preconditioner
811: Output Parameter:
812: . exists - PETSC_TRUE or PETSC_FALSE
814: Level: developer
816: .seealso: PCApplyRichardson()
817: @*/
818: PetscErrorCode PCApplyRichardsonExists(PC pc,PetscBool *exists)
819: {
823: if (pc->ops->applyrichardson) *exists = PETSC_TRUE;
824: else *exists = PETSC_FALSE;
825: return(0);
826: }
828: /*@
829: PCApplyRichardson - Applies several steps of Richardson iteration with
830: the particular preconditioner. This routine is usually used by the
831: Krylov solvers and not the application code directly.
833: Collective on PC
835: Input Parameters:
836: + pc - the preconditioner context
837: . b - the right hand side
838: . w - one work vector
839: . rtol - relative decrease in residual norm convergence criteria
840: . abstol - absolute residual norm convergence criteria
841: . dtol - divergence residual norm increase criteria
842: . its - the number of iterations to apply.
843: - guesszero - if the input x contains nonzero initial guess
845: Output Parameter:
846: + outits - number of iterations actually used (for SOR this always equals its)
847: . reason - the reason the apply terminated
848: - y - the solution (also contains initial guess if guesszero is PETSC_FALSE
850: Notes:
851: Most preconditioners do not support this function. Use the command
852: PCApplyRichardsonExists() to determine if one does.
854: Except for the multigrid PC this routine ignores the convergence tolerances
855: and always runs for the number of iterations
857: Level: developer
859: .seealso: PCApplyRichardsonExists()
860: @*/
861: PetscErrorCode PCApplyRichardson(PC pc,Vec b,Vec y,Vec w,PetscReal rtol,PetscReal abstol, PetscReal dtol,PetscInt its,PetscBool guesszero,PetscInt *outits,PCRichardsonConvergedReason *reason)
862: {
870: if (b == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"b and y must be different vectors");
871: PCSetUp(pc);
872: if (!pc->ops->applyrichardson) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have apply richardson");
873: (*pc->ops->applyrichardson)(pc,b,y,w,rtol,abstol,dtol,its,guesszero,outits,reason);
874: return(0);
875: }
877: /*@
878: PCSetFailedReason - Sets the reason a PCSetUp() failed or PC_NOERROR if it did not fail
880: Logically Collective on PC
882: Input Parameter:
883: + pc - the preconditioner context
884: - reason - the reason it failedx
886: Level: advanced
888: .seealso: PCCreate(), PCApply(), PCDestroy(), PCFailedReason
889: @*/
890: PetscErrorCode PCSetFailedReason(PC pc,PCFailedReason reason)
891: {
893: pc->failedreason = reason;
894: return(0);
895: }
897: /*@
898: PCGetFailedReason - Gets the reason a PCSetUp() failed or PC_NOERROR if it did not fail
900: Logically Collective on PC
902: Input Parameter:
903: . pc - the preconditioner context
905: Output Parameter:
906: . reason - the reason it failed
908: Level: advanced
910: Notes: This is the maximum over reason over all ranks in the PC communicator. It is only valid after
911: a call KSPCheckDot() or KSPCheckNorm() inside a KSPSolve(). It is not valid immediately after a PCSetUp()
912: or PCApply(), then use PCGetFailedReasonRank()
914: .seealso: PCCreate(), PCApply(), PCDestroy(), PCGetFailedReasonRank(), PCSetFailedReason()
915: @*/
916: PetscErrorCode PCGetFailedReason(PC pc,PCFailedReason *reason)
917: {
919: if (pc->setupcalled < 0) *reason = (PCFailedReason)pc->setupcalled;
920: else *reason = pc->failedreason;
921: return(0);
922: }
924: /*@
925: PCGetFailedReasonRank - Gets the reason a PCSetUp() failed or PC_NOERROR if it did not fail on this MPI rank
927: Not Collective on PC
929: Input Parameter:
930: . pc - the preconditioner context
932: Output Parameter:
933: . reason - the reason it failed
935: Notes:
936: Different ranks may have different reasons or no reason, see PCGetFailedReason()
938: Level: advanced
940: .seealso: PCCreate(), PCApply(), PCDestroy(), PCGetFailedReason(), PCSetFailedReason()
941: @*/
942: PetscErrorCode PCGetFailedReasonRank(PC pc,PCFailedReason *reason)
943: {
945: if (pc->setupcalled < 0) *reason = (PCFailedReason)pc->setupcalled;
946: else *reason = pc->failedreason;
947: return(0);
948: }
950: /* Next line needed to deactivate KSP_Solve logging */
951: #include <petsc/private/kspimpl.h>
953: /*
954: a setupcall of 0 indicates never setup,
955: 1 indicates has been previously setup
956: -1 indicates a PCSetUp() was attempted and failed
957: */
958: /*@
959: PCSetUp - Prepares for the use of a preconditioner.
961: Collective on PC
963: Input Parameter:
964: . pc - the preconditioner context
966: Level: developer
968: .seealso: PCCreate(), PCApply(), PCDestroy()
969: @*/
970: PetscErrorCode PCSetUp(PC pc)
971: {
972: PetscErrorCode ierr;
973: const char *def;
974: PetscObjectState matstate, matnonzerostate;
978: if (!pc->mat) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Matrix must be set first");
980: if (pc->setupcalled && pc->reusepreconditioner) {
981: PetscInfo(pc,"Leaving PC with identical preconditioner since reuse preconditioner is set\n");
982: return(0);
983: }
985: PetscObjectStateGet((PetscObject)pc->pmat,&matstate);
986: MatGetNonzeroState(pc->pmat,&matnonzerostate);
987: if (!pc->setupcalled) {
988: PetscInfo(pc,"Setting up PC for first time\n");
989: pc->flag = DIFFERENT_NONZERO_PATTERN;
990: } else if (matstate == pc->matstate) {
991: PetscInfo(pc,"Leaving PC with identical preconditioner since operator is unchanged\n");
992: return(0);
993: } else {
994: if (matnonzerostate > pc->matnonzerostate) {
995: PetscInfo(pc,"Setting up PC with different nonzero pattern\n");
996: pc->flag = DIFFERENT_NONZERO_PATTERN;
997: } else {
998: PetscInfo(pc,"Setting up PC with same nonzero pattern\n");
999: pc->flag = SAME_NONZERO_PATTERN;
1000: }
1001: }
1002: pc->matstate = matstate;
1003: pc->matnonzerostate = matnonzerostate;
1005: if (!((PetscObject)pc)->type_name) {
1006: PCGetDefaultType_Private(pc,&def);
1007: PCSetType(pc,def);
1008: }
1010: MatSetErrorIfFailure(pc->pmat,pc->erroriffailure);
1011: MatSetErrorIfFailure(pc->mat,pc->erroriffailure);
1012: PetscLogEventBegin(PC_SetUp,pc,0,0,0);
1013: if (pc->ops->setup) {
1014: /* do not log solves and applications of preconditioners while constructing preconditioners; perhaps they should be logged separately from the regular solves */
1015: PetscLogEventDeactivatePush(KSP_Solve);
1016: PetscLogEventDeactivatePush(PC_Apply);
1017: (*pc->ops->setup)(pc);
1018: PetscLogEventDeactivatePop(KSP_Solve);
1019: PetscLogEventDeactivatePop(PC_Apply);
1020: }
1021: PetscLogEventEnd(PC_SetUp,pc,0,0,0);
1022: if (!pc->setupcalled) pc->setupcalled = 1;
1023: return(0);
1024: }
1026: /*@
1027: PCSetUpOnBlocks - Sets up the preconditioner for each block in
1028: the block Jacobi, block Gauss-Seidel, and overlapping Schwarz
1029: methods.
1031: Collective on PC
1033: Input Parameters:
1034: . pc - the preconditioner context
1036: Level: developer
1038: .seealso: PCCreate(), PCApply(), PCDestroy(), PCSetUp()
1039: @*/
1040: PetscErrorCode PCSetUpOnBlocks(PC pc)
1041: {
1046: if (!pc->ops->setuponblocks) return(0);
1047: PetscLogEventBegin(PC_SetUpOnBlocks,pc,0,0,0);
1048: (*pc->ops->setuponblocks)(pc);
1049: PetscLogEventEnd(PC_SetUpOnBlocks,pc,0,0,0);
1050: return(0);
1051: }
1053: /*@C
1054: PCSetModifySubMatrices - Sets a user-defined routine for modifying the
1055: submatrices that arise within certain subdomain-based preconditioners.
1056: The basic submatrices are extracted from the preconditioner matrix as
1057: usual; the user can then alter these (for example, to set different boundary
1058: conditions for each submatrix) before they are used for the local solves.
1060: Logically Collective on PC
1062: Input Parameters:
1063: + pc - the preconditioner context
1064: . func - routine for modifying the submatrices
1065: - ctx - optional user-defined context (may be null)
1067: Calling sequence of func:
1068: $ func (PC pc,PetscInt nsub,IS *row,IS *col,Mat *submat,void *ctx);
1070: + row - an array of index sets that contain the global row numbers
1071: that comprise each local submatrix
1072: . col - an array of index sets that contain the global column numbers
1073: that comprise each local submatrix
1074: . submat - array of local submatrices
1075: - ctx - optional user-defined context for private data for the
1076: user-defined func routine (may be null)
1078: Notes:
1079: PCSetModifySubMatrices() MUST be called before KSPSetUp() and
1080: KSPSolve().
1082: A routine set by PCSetModifySubMatrices() is currently called within
1083: the block Jacobi (PCBJACOBI) and additive Schwarz (PCASM)
1084: preconditioners. All other preconditioners ignore this routine.
1086: Level: advanced
1088: .seealso: PCModifySubMatrices()
1089: @*/
1090: PetscErrorCode PCSetModifySubMatrices(PC pc,PetscErrorCode (*func)(PC,PetscInt,const IS[],const IS[],Mat[],void*),void *ctx)
1091: {
1094: pc->modifysubmatrices = func;
1095: pc->modifysubmatricesP = ctx;
1096: return(0);
1097: }
1099: /*@C
1100: PCModifySubMatrices - Calls an optional user-defined routine within
1101: certain preconditioners if one has been set with PCSetModifySubMatrices().
1103: Collective on PC
1105: Input Parameters:
1106: + pc - the preconditioner context
1107: . nsub - the number of local submatrices
1108: . row - an array of index sets that contain the global row numbers
1109: that comprise each local submatrix
1110: . col - an array of index sets that contain the global column numbers
1111: that comprise each local submatrix
1112: . submat - array of local submatrices
1113: - ctx - optional user-defined context for private data for the
1114: user-defined routine (may be null)
1116: Output Parameter:
1117: . submat - array of local submatrices (the entries of which may
1118: have been modified)
1120: Notes:
1121: The user should NOT generally call this routine, as it will
1122: automatically be called within certain preconditioners (currently
1123: block Jacobi, additive Schwarz) if set.
1125: The basic submatrices are extracted from the preconditioner matrix
1126: as usual; the user can then alter these (for example, to set different
1127: boundary conditions for each submatrix) before they are used for the
1128: local solves.
1130: Level: developer
1132: .seealso: PCSetModifySubMatrices()
1133: @*/
1134: PetscErrorCode PCModifySubMatrices(PC pc,PetscInt nsub,const IS row[],const IS col[],Mat submat[],void *ctx)
1135: {
1140: if (!pc->modifysubmatrices) return(0);
1141: PetscLogEventBegin(PC_ModifySubMatrices,pc,0,0,0);
1142: (*pc->modifysubmatrices)(pc,nsub,row,col,submat,ctx);
1143: PetscLogEventEnd(PC_ModifySubMatrices,pc,0,0,0);
1144: return(0);
1145: }
1147: /*@
1148: PCSetOperators - Sets the matrix associated with the linear system and
1149: a (possibly) different one associated with the preconditioner.
1151: Logically Collective on PC
1153: Input Parameters:
1154: + pc - the preconditioner context
1155: . Amat - the matrix that defines the linear system
1156: - Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
1158: Notes:
1159: Passing a NULL for Amat or Pmat removes the matrix that is currently used.
1161: If you wish to replace either Amat or Pmat but leave the other one untouched then
1162: first call KSPGetOperators() to get the one you wish to keep, call PetscObjectReference()
1163: on it and then pass it back in in your call to KSPSetOperators().
1165: More Notes about Repeated Solution of Linear Systems:
1166: PETSc does NOT reset the matrix entries of either Amat or Pmat
1167: to zero after a linear solve; the user is completely responsible for
1168: matrix assembly. See the routine MatZeroEntries() if desiring to
1169: zero all elements of a matrix.
1171: Level: intermediate
1173: .seealso: PCGetOperators(), MatZeroEntries()
1174: @*/
1175: PetscErrorCode PCSetOperators(PC pc,Mat Amat,Mat Pmat)
1176: {
1177: PetscErrorCode ierr;
1178: PetscInt m1,n1,m2,n2;
1186: if (pc->setupcalled && pc->mat && pc->pmat && Amat && Pmat) {
1187: MatGetLocalSize(Amat,&m1,&n1);
1188: MatGetLocalSize(pc->mat,&m2,&n2);
1189: 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);
1190: MatGetLocalSize(Pmat,&m1,&n1);
1191: MatGetLocalSize(pc->pmat,&m2,&n2);
1192: 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);
1193: }
1195: if (Pmat != pc->pmat) {
1196: /* changing the operator that defines the preconditioner thus reneed to clear current states so new preconditioner is built */
1197: pc->matnonzerostate = -1;
1198: pc->matstate = -1;
1199: }
1201: /* reference first in case the matrices are the same */
1202: if (Amat) {PetscObjectReference((PetscObject)Amat);}
1203: MatDestroy(&pc->mat);
1204: if (Pmat) {PetscObjectReference((PetscObject)Pmat);}
1205: MatDestroy(&pc->pmat);
1206: pc->mat = Amat;
1207: pc->pmat = Pmat;
1208: return(0);
1209: }
1211: /*@
1212: PCSetReusePreconditioner - reuse the current preconditioner even if the operator in the preconditioner has changed.
1214: Logically Collective on PC
1216: Input Parameters:
1217: + pc - the preconditioner context
1218: - flag - PETSC_TRUE do not compute a new preconditioner, PETSC_FALSE do compute a new preconditioner
1220: Level: intermediate
1222: .seealso: PCGetOperators(), MatZeroEntries(), PCGetReusePreconditioner(), KSPSetReusePreconditioner()
1223: @*/
1224: PetscErrorCode PCSetReusePreconditioner(PC pc,PetscBool flag)
1225: {
1229: pc->reusepreconditioner = flag;
1230: return(0);
1231: }
1233: /*@
1234: PCGetReusePreconditioner - Determines if the PC reuses the current preconditioner even if the operator in the preconditioner has changed.
1236: Not Collective
1238: Input Parameter:
1239: . pc - the preconditioner context
1241: Output Parameter:
1242: . flag - PETSC_TRUE do not compute a new preconditioner, PETSC_FALSE do compute a new preconditioner
1244: Level: intermediate
1246: .seealso: PCGetOperators(), MatZeroEntries(), PCSetReusePreconditioner()
1247: @*/
1248: PetscErrorCode PCGetReusePreconditioner(PC pc,PetscBool *flag)
1249: {
1253: *flag = pc->reusepreconditioner;
1254: return(0);
1255: }
1257: /*@
1258: PCGetOperators - Gets the matrix associated with the linear system and
1259: possibly a different one associated with the preconditioner.
1261: Not collective, though parallel Mats are returned if the PC is parallel
1263: Input Parameter:
1264: . pc - the preconditioner context
1266: Output Parameters:
1267: + Amat - the matrix defining the linear system
1268: - Pmat - the matrix from which the preconditioner is constructed, usually the same as Amat.
1270: Level: intermediate
1272: Notes:
1273: Does not increase the reference count of the matrices, so you should not destroy them
1275: Alternative usage: If the operators have NOT been set with KSP/PCSetOperators() then the operators
1276: are created in PC and returned to the user. In this case, if both operators
1277: mat and pmat are requested, two DIFFERENT operators will be returned. If
1278: only one is requested both operators in the PC will be the same (i.e. as
1279: if one had called KSP/PCSetOperators() with the same argument for both Mats).
1280: The user must set the sizes of the returned matrices and their type etc just
1281: as if the user created them with MatCreate(). For example,
1283: $ KSP/PCGetOperators(ksp/pc,&Amat,NULL); is equivalent to
1284: $ set size, type, etc of Amat
1286: $ MatCreate(comm,&mat);
1287: $ KSP/PCSetOperators(ksp/pc,Amat,Amat);
1288: $ PetscObjectDereference((PetscObject)mat);
1289: $ set size, type, etc of Amat
1291: and
1293: $ KSP/PCGetOperators(ksp/pc,&Amat,&Pmat); is equivalent to
1294: $ set size, type, etc of Amat and Pmat
1296: $ MatCreate(comm,&Amat);
1297: $ MatCreate(comm,&Pmat);
1298: $ KSP/PCSetOperators(ksp/pc,Amat,Pmat);
1299: $ PetscObjectDereference((PetscObject)Amat);
1300: $ PetscObjectDereference((PetscObject)Pmat);
1301: $ set size, type, etc of Amat and Pmat
1303: The rational for this support is so that when creating a TS, SNES, or KSP the hierarchy
1304: of underlying objects (i.e. SNES, KSP, PC, Mat) and their livespans can be completely
1305: managed by the top most level object (i.e. the TS, SNES, or KSP). Another way to look
1306: at this is when you create a SNES you do not NEED to create a KSP and attach it to
1307: the SNES object (the SNES object manages it for you). Similarly when you create a KSP
1308: you do not need to attach a PC to it (the KSP object manages the PC object for you).
1309: Thus, why should YOU have to create the Mat and attach it to the SNES/KSP/PC, when
1310: it can be created for you?
1313: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperatorsSet()
1314: @*/
1315: PetscErrorCode PCGetOperators(PC pc,Mat *Amat,Mat *Pmat)
1316: {
1321: if (Amat) {
1322: if (!pc->mat) {
1323: if (pc->pmat && !Pmat) { /* Apmat has been set, but user did not request it, so use for Amat */
1324: pc->mat = pc->pmat;
1325: PetscObjectReference((PetscObject)pc->mat);
1326: } else { /* both Amat and Pmat are empty */
1327: MatCreate(PetscObjectComm((PetscObject)pc),&pc->mat);
1328: if (!Pmat) { /* user did NOT request Pmat, so make same as Amat */
1329: pc->pmat = pc->mat;
1330: PetscObjectReference((PetscObject)pc->pmat);
1331: }
1332: }
1333: }
1334: *Amat = pc->mat;
1335: }
1336: if (Pmat) {
1337: if (!pc->pmat) {
1338: if (pc->mat && !Amat) { /* Amat has been set but was not requested, so use for pmat */
1339: pc->pmat = pc->mat;
1340: PetscObjectReference((PetscObject)pc->pmat);
1341: } else {
1342: MatCreate(PetscObjectComm((PetscObject)pc),&pc->pmat);
1343: if (!Amat) { /* user did NOT request Amat, so make same as Pmat */
1344: pc->mat = pc->pmat;
1345: PetscObjectReference((PetscObject)pc->mat);
1346: }
1347: }
1348: }
1349: *Pmat = pc->pmat;
1350: }
1351: return(0);
1352: }
1354: /*@C
1355: PCGetOperatorsSet - Determines if the matrix associated with the linear system and
1356: possibly a different one associated with the preconditioner have been set in the PC.
1358: Not collective, though the results on all processes should be the same
1360: Input Parameter:
1361: . pc - the preconditioner context
1363: Output Parameters:
1364: + mat - the matrix associated with the linear system was set
1365: - pmat - matrix associated with the preconditioner was set, usually the same
1367: Level: intermediate
1369: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperators()
1370: @*/
1371: PetscErrorCode PCGetOperatorsSet(PC pc,PetscBool *mat,PetscBool *pmat)
1372: {
1375: if (mat) *mat = (pc->mat) ? PETSC_TRUE : PETSC_FALSE;
1376: if (pmat) *pmat = (pc->pmat) ? PETSC_TRUE : PETSC_FALSE;
1377: return(0);
1378: }
1380: /*@
1381: PCFactorGetMatrix - Gets the factored matrix from the
1382: preconditioner context. This routine is valid only for the LU,
1383: incomplete LU, Cholesky, and incomplete Cholesky methods.
1385: Not Collective on PC though Mat is parallel if PC is parallel
1387: Input Parameters:
1388: . pc - the preconditioner context
1390: Output parameters:
1391: . mat - the factored matrix
1393: Level: advanced
1395: Notes:
1396: Does not increase the reference count for the matrix so DO NOT destroy it
1398: @*/
1399: PetscErrorCode PCFactorGetMatrix(PC pc,Mat *mat)
1400: {
1406: if (pc->ops->getfactoredmatrix) {
1407: (*pc->ops->getfactoredmatrix)(pc,mat);
1408: } else SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC type does not support getting factor matrix");
1409: return(0);
1410: }
1412: /*@C
1413: PCSetOptionsPrefix - Sets the prefix used for searching for all
1414: PC options in the database.
1416: Logically Collective on PC
1418: Input Parameters:
1419: + pc - the preconditioner context
1420: - prefix - the prefix string to prepend to all PC option requests
1422: Notes:
1423: A hyphen (-) must NOT be given at the beginning of the prefix name.
1424: The first character of all runtime options is AUTOMATICALLY the
1425: hyphen.
1427: Level: advanced
1429: .seealso: PCAppendOptionsPrefix(), PCGetOptionsPrefix()
1430: @*/
1431: PetscErrorCode PCSetOptionsPrefix(PC pc,const char prefix[])
1432: {
1437: PetscObjectSetOptionsPrefix((PetscObject)pc,prefix);
1438: return(0);
1439: }
1441: /*@C
1442: PCAppendOptionsPrefix - Appends to the prefix used for searching for all
1443: PC options in the database.
1445: Logically Collective on PC
1447: Input Parameters:
1448: + pc - the preconditioner context
1449: - prefix - the prefix string to prepend to all PC option requests
1451: Notes:
1452: A hyphen (-) must NOT be given at the beginning of the prefix name.
1453: The first character of all runtime options is AUTOMATICALLY the
1454: hyphen.
1456: Level: advanced
1458: .seealso: PCSetOptionsPrefix(), PCGetOptionsPrefix()
1459: @*/
1460: PetscErrorCode PCAppendOptionsPrefix(PC pc,const char prefix[])
1461: {
1466: PetscObjectAppendOptionsPrefix((PetscObject)pc,prefix);
1467: return(0);
1468: }
1470: /*@C
1471: PCGetOptionsPrefix - Gets the prefix used for searching for all
1472: PC options in the database.
1474: Not Collective
1476: Input Parameters:
1477: . pc - the preconditioner context
1479: Output Parameters:
1480: . prefix - pointer to the prefix string used, is returned
1482: Notes:
1483: On the fortran side, the user should pass in a string 'prifix' of
1484: sufficient length to hold the prefix.
1486: Level: advanced
1488: .seealso: PCSetOptionsPrefix(), PCAppendOptionsPrefix()
1489: @*/
1490: PetscErrorCode PCGetOptionsPrefix(PC pc,const char *prefix[])
1491: {
1497: PetscObjectGetOptionsPrefix((PetscObject)pc,prefix);
1498: return(0);
1499: }
1501: /*
1502: Indicates the right hand side will be changed by KSPSolve(), this occurs for a few
1503: preconditioners including BDDC and Eisentat that transform the equations before applying
1504: the Krylov methods
1505: */
1506: PETSC_INTERN PetscErrorCode PCPreSolveChangeRHS(PC pc,PetscBool *change)
1507: {
1513: *change = PETSC_FALSE;
1514: PetscTryMethod(pc,"PCPreSolveChangeRHS_C",(PC,PetscBool*),(pc,change));
1515: return(0);
1516: }
1518: /*@
1519: PCPreSolve - Optional pre-solve phase, intended for any
1520: preconditioner-specific actions that must be performed before
1521: the iterative solve itself.
1523: Collective on PC
1525: Input Parameters:
1526: + pc - the preconditioner context
1527: - ksp - the Krylov subspace context
1529: Level: developer
1531: Sample of Usage:
1532: .vb
1533: PCPreSolve(pc,ksp);
1534: KSPSolve(ksp,b,x);
1535: PCPostSolve(pc,ksp);
1536: .ve
1538: Notes:
1539: The pre-solve phase is distinct from the PCSetUp() phase.
1541: KSPSolve() calls this directly, so is rarely called by the user.
1543: .seealso: PCPostSolve()
1544: @*/
1545: PetscErrorCode PCPreSolve(PC pc,KSP ksp)
1546: {
1548: Vec x,rhs;
1553: pc->presolvedone++;
1554: if (pc->presolvedone > 2) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot embed PCPreSolve() more than twice");
1555: KSPGetSolution(ksp,&x);
1556: KSPGetRhs(ksp,&rhs);
1558: if (pc->ops->presolve) {
1559: (*pc->ops->presolve)(pc,ksp,rhs,x);
1560: }
1561: return(0);
1562: }
1564: /*@
1565: PCPostSolve - Optional post-solve phase, intended for any
1566: preconditioner-specific actions that must be performed after
1567: the iterative solve itself.
1569: Collective on PC
1571: Input Parameters:
1572: + pc - the preconditioner context
1573: - ksp - the Krylov subspace context
1575: Sample of Usage:
1576: .vb
1577: PCPreSolve(pc,ksp);
1578: KSPSolve(ksp,b,x);
1579: PCPostSolve(pc,ksp);
1580: .ve
1582: Note:
1583: KSPSolve() calls this routine directly, so it is rarely called by the user.
1585: Level: developer
1587: .seealso: PCPreSolve(), KSPSolve()
1588: @*/
1589: PetscErrorCode PCPostSolve(PC pc,KSP ksp)
1590: {
1592: Vec x,rhs;
1597: pc->presolvedone--;
1598: KSPGetSolution(ksp,&x);
1599: KSPGetRhs(ksp,&rhs);
1600: if (pc->ops->postsolve) {
1601: (*pc->ops->postsolve)(pc,ksp,rhs,x);
1602: }
1603: return(0);
1604: }
1606: /*@C
1607: PCLoad - Loads a PC that has been stored in binary with PCView().
1609: Collective on PetscViewer
1611: Input Parameters:
1612: + newdm - the newly loaded PC, this needs to have been created with PCCreate() or
1613: some related function before a call to PCLoad().
1614: - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()
1616: Level: intermediate
1618: Notes:
1619: The type is determined by the data in the file, any type set into the PC before this call is ignored.
1621: Notes for advanced users:
1622: Most users should not need to know the details of the binary storage
1623: format, since PCLoad() and PCView() completely hide these details.
1624: But for anyone who's interested, the standard binary matrix storage
1625: format is
1626: .vb
1627: has not yet been determined
1628: .ve
1630: .seealso: PetscViewerBinaryOpen(), PCView(), MatLoad(), VecLoad()
1631: @*/
1632: PetscErrorCode PCLoad(PC newdm, PetscViewer viewer)
1633: {
1635: PetscBool isbinary;
1636: PetscInt classid;
1637: char type[256];
1642: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
1643: if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1645: PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
1646: if (classid != PC_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)newdm),PETSC_ERR_ARG_WRONG,"Not PC next in file");
1647: PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
1648: PCSetType(newdm, type);
1649: if (newdm->ops->load) {
1650: (*newdm->ops->load)(newdm,viewer);
1651: }
1652: return(0);
1653: }
1655: #include <petscdraw.h>
1656: #if defined(PETSC_HAVE_SAWS)
1657: #include <petscviewersaws.h>
1658: #endif
1660: /*@C
1661: PCViewFromOptions - View from Options
1663: Collective on PC
1665: Input Parameters:
1666: + A - the PC context
1667: . obj - Optional object
1668: - name - command line option
1670: Level: intermediate
1671: .seealso: PC, PCView, PetscObjectViewFromOptions(), PCCreate()
1672: @*/
1673: PetscErrorCode PCViewFromOptions(PC A,PetscObject obj,const char name[])
1674: {
1679: PetscObjectViewFromOptions((PetscObject)A,obj,name);
1680: return(0);
1681: }
1683: /*@C
1684: PCView - Prints the PC data structure.
1686: Collective on PC
1688: Input Parameters:
1689: + PC - the PC context
1690: - viewer - optional visualization context
1692: Note:
1693: The available visualization contexts include
1694: + PETSC_VIEWER_STDOUT_SELF - standard output (default)
1695: - PETSC_VIEWER_STDOUT_WORLD - synchronized standard
1696: output where only the first processor opens
1697: the file. All other processors send their
1698: data to the first processor to print.
1700: The user can open an alternative visualization contexts with
1701: PetscViewerASCIIOpen() (output to a specified file).
1703: Level: developer
1705: .seealso: KSPView(), PetscViewerASCIIOpen()
1706: @*/
1707: PetscErrorCode PCView(PC pc,PetscViewer viewer)
1708: {
1709: PCType cstr;
1711: PetscBool iascii,isstring,isbinary,isdraw;
1712: #if defined(PETSC_HAVE_SAWS)
1713: PetscBool issaws;
1714: #endif
1718: if (!viewer) {
1719: PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)pc),&viewer);
1720: }
1724: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
1725: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
1726: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
1727: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
1728: #if defined(PETSC_HAVE_SAWS)
1729: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
1730: #endif
1732: if (iascii) {
1733: PetscObjectPrintClassNamePrefixType((PetscObject)pc,viewer);
1734: if (!pc->setupcalled) {
1735: PetscViewerASCIIPrintf(viewer," PC has not been set up so information may be incomplete\n");
1736: }
1737: if (pc->ops->view) {
1738: PetscViewerASCIIPushTab(viewer);
1739: (*pc->ops->view)(pc,viewer);
1740: PetscViewerASCIIPopTab(viewer);
1741: }
1742: if (pc->mat) {
1743: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO);
1744: if (pc->pmat == pc->mat) {
1745: PetscViewerASCIIPrintf(viewer," linear system matrix = precond matrix:\n");
1746: PetscViewerASCIIPushTab(viewer);
1747: MatView(pc->mat,viewer);
1748: PetscViewerASCIIPopTab(viewer);
1749: } else {
1750: if (pc->pmat) {
1751: PetscViewerASCIIPrintf(viewer," linear system matrix followed by preconditioner matrix:\n");
1752: } else {
1753: PetscViewerASCIIPrintf(viewer," linear system matrix:\n");
1754: }
1755: PetscViewerASCIIPushTab(viewer);
1756: MatView(pc->mat,viewer);
1757: if (pc->pmat) {MatView(pc->pmat,viewer);}
1758: PetscViewerASCIIPopTab(viewer);
1759: }
1760: PetscViewerPopFormat(viewer);
1761: }
1762: } else if (isstring) {
1763: PCGetType(pc,&cstr);
1764: PetscViewerStringSPrintf(viewer," PCType: %-7.7s",cstr);
1765: if (pc->ops->view) {(*pc->ops->view)(pc,viewer);}
1766: if (pc->mat) {MatView(pc->mat,viewer);}
1767: if (pc->pmat && pc->pmat != pc->mat) {MatView(pc->pmat,viewer);}
1768: } else if (isbinary) {
1769: PetscInt classid = PC_FILE_CLASSID;
1770: MPI_Comm comm;
1771: PetscMPIInt rank;
1772: char type[256];
1774: PetscObjectGetComm((PetscObject)pc,&comm);
1775: MPI_Comm_rank(comm,&rank);
1776: if (!rank) {
1777: PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT);
1778: PetscStrncpy(type,((PetscObject)pc)->type_name,256);
1779: PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR);
1780: }
1781: if (pc->ops->view) {
1782: (*pc->ops->view)(pc,viewer);
1783: }
1784: } else if (isdraw) {
1785: PetscDraw draw;
1786: char str[25];
1787: PetscReal x,y,bottom,h;
1788: PetscInt n;
1790: PetscViewerDrawGetDraw(viewer,0,&draw);
1791: PetscDrawGetCurrentPoint(draw,&x,&y);
1792: if (pc->mat) {
1793: MatGetSize(pc->mat,&n,NULL);
1794: PetscSNPrintf(str,25,"PC: %s (%D)",((PetscObject)pc)->type_name,n);
1795: } else {
1796: PetscSNPrintf(str,25,"PC: %s",((PetscObject)pc)->type_name);
1797: }
1798: PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);
1799: bottom = y - h;
1800: PetscDrawPushCurrentPoint(draw,x,bottom);
1801: if (pc->ops->view) {
1802: (*pc->ops->view)(pc,viewer);
1803: }
1804: PetscDrawPopCurrentPoint(draw);
1805: #if defined(PETSC_HAVE_SAWS)
1806: } else if (issaws) {
1807: PetscMPIInt rank;
1809: PetscObjectName((PetscObject)pc);
1810: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
1811: if (!((PetscObject)pc)->amsmem && !rank) {
1812: PetscObjectViewSAWs((PetscObject)pc,viewer);
1813: }
1814: if (pc->mat) {MatView(pc->mat,viewer);}
1815: if (pc->pmat && pc->pmat != pc->mat) {MatView(pc->pmat,viewer);}
1816: #endif
1817: }
1818: return(0);
1819: }
1821: /*@C
1822: PCRegister - Adds a method to the preconditioner package.
1824: Not collective
1826: Input Parameters:
1827: + name_solver - name of a new user-defined solver
1828: - routine_create - routine to create method context
1830: Notes:
1831: PCRegister() may be called multiple times to add several user-defined preconditioners.
1833: Sample usage:
1834: .vb
1835: PCRegister("my_solver", MySolverCreate);
1836: .ve
1838: Then, your solver can be chosen with the procedural interface via
1839: $ PCSetType(pc,"my_solver")
1840: or at runtime via the option
1841: $ -pc_type my_solver
1843: Level: advanced
1845: .seealso: PCRegisterAll()
1846: @*/
1847: PetscErrorCode PCRegister(const char sname[],PetscErrorCode (*function)(PC))
1848: {
1852: PCInitializePackage();
1853: PetscFunctionListAdd(&PCList,sname,function);
1854: return(0);
1855: }
1857: static PetscErrorCode MatMult_PC(Mat A,Vec X,Vec Y)
1858: {
1859: PC pc;
1863: MatShellGetContext(A,&pc);
1864: PCApply(pc,X,Y);
1865: return(0);
1866: }
1868: /*@
1869: PCComputeOperator - Computes the explicit preconditioned operator.
1871: Collective on PC
1873: Input Parameter:
1874: + pc - the preconditioner object
1875: - mattype - the matrix type to be used for the operator
1877: Output Parameter:
1878: . mat - the explict preconditioned operator
1880: Notes:
1881: This computation is done by applying the operators to columns of the identity matrix.
1882: This routine is costly in general, and is recommended for use only with relatively small systems.
1883: Currently, this routine uses a dense matrix format when mattype == NULL
1885: Level: advanced
1887: .seealso: KSPComputeOperator(), MatType
1889: @*/
1890: PetscErrorCode PCComputeOperator(PC pc,MatType mattype,Mat *mat)
1891: {
1893: PetscInt N,M,m,n;
1894: Mat A,Apc;
1899: PCGetOperators(pc,&A,NULL);
1900: MatGetLocalSize(A,&m,&n);
1901: MatGetSize(A,&M,&N);
1902: MatCreateShell(PetscObjectComm((PetscObject)pc),m,n,M,N,pc,&Apc);
1903: MatShellSetOperation(Apc,MATOP_MULT,(void (*)(void))MatMult_PC);
1904: MatComputeOperator(Apc,mattype,mat);
1905: MatDestroy(&Apc);
1906: return(0);
1907: }
1909: /*@
1910: PCSetCoordinates - sets the coordinates of all the nodes on the local process
1912: Collective on PC
1914: Input Parameters:
1915: + pc - the solver context
1916: . dim - the dimension of the coordinates 1, 2, or 3
1917: . nloc - the blocked size of the coordinates array
1918: - coords - the coordinates array
1920: Level: intermediate
1922: Notes:
1923: coords is an array of the dim coordinates for the nodes on
1924: the local processor, of size dim*nloc.
1925: If there are 108 equation on a processor
1926: for a displacement finite element discretization of elasticity (so
1927: that there are nloc = 36 = 108/3 nodes) then the array must have 108
1928: double precision values (ie, 3 * 36). These x y z coordinates
1929: should be ordered for nodes 0 to N-1 like so: [ 0.x, 0.y, 0.z, 1.x,
1930: ... , N-1.z ].
1932: .seealso: MatSetNearNullSpace()
1933: @*/
1934: PetscErrorCode PCSetCoordinates(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[])
1935: {
1941: PetscTryMethod(pc,"PCSetCoordinates_C",(PC,PetscInt,PetscInt,PetscReal*),(pc,dim,nloc,coords));
1942: return(0);
1943: }
1945: /*@
1946: PCGetInterpolations - Gets interpolation matrices for all levels (except level 0)
1948: Logically Collective on PC
1950: Input Parameters:
1951: + pc - the precondition context
1953: Output Parameter:
1954: - num_levels - the number of levels
1955: . interpolations - the interpolation matrices (size of num_levels-1)
1957: Level: advanced
1959: .keywords: MG, GAMG, BoomerAMG, multigrid, interpolation, level
1961: .seealso: PCMGGetRestriction(), PCMGSetInterpolation(), PCMGGetInterpolation(), PCGetCoarseOperators()
1962: @*/
1963: PetscErrorCode PCGetInterpolations(PC pc,PetscInt *num_levels,Mat *interpolations[])
1964: {
1971: PetscUseMethod(pc,"PCGetInterpolations_C",(PC,PetscInt*,Mat*[]),(pc,num_levels,interpolations));
1972: return(0);
1973: }
1975: /*@
1976: PCGetCoarseOperators - Gets coarse operator matrices for all levels (except the finest level)
1978: Logically Collective on PC
1980: Input Parameters:
1981: + pc - the precondition context
1983: Output Parameter:
1984: - num_levels - the number of levels
1985: . coarseOperators - the coarse operator matrices (size of num_levels-1)
1987: Level: advanced
1989: .keywords: MG, GAMG, BoomerAMG, get, multigrid, interpolation, level
1991: .seealso: PCMGGetRestriction(), PCMGSetInterpolation(), PCMGGetRScale(), PCMGGetInterpolation(), PCGetInterpolations()
1992: @*/
1993: PetscErrorCode PCGetCoarseOperators(PC pc,PetscInt *num_levels,Mat *coarseOperators[])
1994: {
2001: PetscUseMethod(pc,"PCGetCoarseOperators_C",(PC,PetscInt*,Mat*[]),(pc,num_levels,coarseOperators));
2002: return(0);
2003: }