Actual source code: precon.c
petsc-3.12.5 2020-03-29
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_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: /*@
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 = 0; 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 = 0;
382: PCInitializePackage();
384: PetscHeaderCreate(pc,PC_CLASSID,"PC","Preconditioner","PC",comm,PCDestroy,PCView);
386: pc->mat = 0;
387: pc->pmat = 0;
388: pc->setupcalled = 0;
389: pc->setfromoptionscalled = 0;
390: pc->data = 0;
391: pc->diagonalscale = PETSC_FALSE;
392: pc->diagonalscaleleft = 0;
393: pc->diagonalscaleright = 0;
395: pc->modifysubmatrices = 0;
396: pc->modifysubmatricesP = 0;
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 KSPLQR the pmat may be of a different size than mat */
433: MatGetLocalSize(pc->pmat,&m,&n);
434: VecGetLocalSize(x,&nv);
435: VecGetLocalSize(y,&mv);
436: if (mv != m) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Preconditioner number of local rows %D does not equal resulting vector number of rows %D",m,mv);
437: if (nv != n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Preconditioner number of local columns %D does not equal resulting vector number of rows %D",n,nv);
438: VecSetErrorIfLocked(y,3);
440: PCSetUp(pc);
441: if (!pc->ops->apply) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have apply");
442: VecLockReadPush(x);
443: PetscLogEventBegin(PC_Apply,pc,x,y,0);
444: (*pc->ops->apply)(pc,x,y);
445: PetscLogEventEnd(PC_Apply,pc,x,y,0);
446: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
447: VecLockReadPop(x);
448: return(0);
449: }
451: /*@
452: PCApplySymmetricLeft - Applies the left part of a symmetric preconditioner to a vector.
454: Collective on PC
456: Input Parameters:
457: + pc - the preconditioner context
458: - x - input vector
460: Output Parameter:
461: . y - output vector
463: Notes:
464: Currently, this routine is implemented only for PCICC and PCJACOBI preconditioners.
466: Level: developer
468: .seealso: PCApply(), PCApplySymmetricRight()
469: @*/
470: PetscErrorCode PCApplySymmetricLeft(PC pc,Vec x,Vec y)
471: {
478: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
479: if (pc->erroriffailure) {VecValidValues(x,2,PETSC_TRUE);}
480: PCSetUp(pc);
481: if (!pc->ops->applysymmetricleft) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have left symmetric apply");
482: VecLockReadPush(x);
483: PetscLogEventBegin(PC_ApplySymmetricLeft,pc,x,y,0);
484: (*pc->ops->applysymmetricleft)(pc,x,y);
485: PetscLogEventEnd(PC_ApplySymmetricLeft,pc,x,y,0);
486: VecLockReadPop(x);
487: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
488: return(0);
489: }
491: /*@
492: PCApplySymmetricRight - Applies the right part of a symmetric preconditioner to a vector.
494: Collective on PC
496: Input Parameters:
497: + pc - the preconditioner context
498: - x - input vector
500: Output Parameter:
501: . y - output vector
503: Level: developer
505: Notes:
506: Currently, this routine is implemented only for PCICC and PCJACOBI preconditioners.
508: .seealso: PCApply(), PCApplySymmetricLeft()
509: @*/
510: PetscErrorCode PCApplySymmetricRight(PC pc,Vec x,Vec y)
511: {
518: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
519: if (pc->erroriffailure) {VecValidValues(x,2,PETSC_TRUE);}
520: PCSetUp(pc);
521: if (!pc->ops->applysymmetricright) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have left symmetric apply");
522: VecLockReadPush(x);
523: PetscLogEventBegin(PC_ApplySymmetricRight,pc,x,y,0);
524: (*pc->ops->applysymmetricright)(pc,x,y);
525: PetscLogEventEnd(PC_ApplySymmetricRight,pc,x,y,0);
526: VecLockReadPop(x);
527: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
528: return(0);
529: }
531: /*@
532: PCApplyTranspose - Applies the transpose of preconditioner to a vector.
534: Collective on PC
536: Input Parameters:
537: + pc - the preconditioner context
538: - x - input vector
540: Output Parameter:
541: . y - output vector
543: Notes:
544: For complex numbers this applies the non-Hermitian transpose.
546: Developer Notes:
547: We need to implement a PCApplyHermitianTranspose()
549: Level: developer
551: .seealso: PCApply(), PCApplyBAorAB(), PCApplyBAorABTranspose(), PCApplyTransposeExists()
552: @*/
553: PetscErrorCode PCApplyTranspose(PC pc,Vec x,Vec y)
554: {
561: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
562: if (pc->erroriffailure) {VecValidValues(x,2,PETSC_TRUE);}
563: PCSetUp(pc);
564: if (!pc->ops->applytranspose) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have apply transpose");
565: VecLockReadPush(x);
566: PetscLogEventBegin(PC_Apply,pc,x,y,0);
567: (*pc->ops->applytranspose)(pc,x,y);
568: PetscLogEventEnd(PC_Apply,pc,x,y,0);
569: VecLockReadPop(x);
570: if (pc->erroriffailure) {VecValidValues(y,3,PETSC_FALSE);}
571: return(0);
572: }
574: /*@
575: PCApplyTransposeExists - Test whether the preconditioner has a transpose apply operation
577: Collective on PC
579: Input Parameters:
580: . pc - the preconditioner context
582: Output Parameter:
583: . flg - PETSC_TRUE if a transpose operation is defined
585: Level: developer
587: .seealso: PCApplyTranspose()
588: @*/
589: PetscErrorCode PCApplyTransposeExists(PC pc,PetscBool *flg)
590: {
594: if (pc->ops->applytranspose) *flg = PETSC_TRUE;
595: else *flg = PETSC_FALSE;
596: return(0);
597: }
599: /*@
600: PCApplyBAorAB - Applies the preconditioner and operator to a vector. y = B*A*x or y = A*B*x.
602: Collective on PC
604: Input Parameters:
605: + pc - the preconditioner context
606: . side - indicates the preconditioner side, one of PC_LEFT, PC_RIGHT, or PC_SYMMETRIC
607: . x - input vector
608: - work - work vector
610: Output Parameter:
611: . y - output vector
613: Level: developer
615: Notes:
616: 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
617: specific KSPSolve() method must also be written to handle the post-solve "correction" for the diagonal scaling.
619: .seealso: PCApply(), PCApplyTranspose(), PCApplyBAorABTranspose()
620: @*/
621: PetscErrorCode PCApplyBAorAB(PC pc,PCSide side,Vec x,Vec y,Vec work)
622: {
630: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
631: 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");
632: if (pc->diagonalscale && side == PC_SYMMETRIC) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot include diagonal scaling with symmetric preconditioner application");
633: if (pc->erroriffailure) {VecValidValues(x,3,PETSC_TRUE);}
635: PCSetUp(pc);
636: if (pc->diagonalscale) {
637: if (pc->ops->applyBA) {
638: Vec work2; /* this is expensive, but to fix requires a second work vector argument to PCApplyBAorAB() */
639: VecDuplicate(x,&work2);
640: PCDiagonalScaleRight(pc,x,work2);
641: (*pc->ops->applyBA)(pc,side,work2,y,work);
642: PCDiagonalScaleLeft(pc,y,y);
643: VecDestroy(&work2);
644: } else if (side == PC_RIGHT) {
645: PCDiagonalScaleRight(pc,x,y);
646: PCApply(pc,y,work);
647: MatMult(pc->mat,work,y);
648: PCDiagonalScaleLeft(pc,y,y);
649: } else if (side == PC_LEFT) {
650: PCDiagonalScaleRight(pc,x,y);
651: MatMult(pc->mat,y,work);
652: PCApply(pc,work,y);
653: PCDiagonalScaleLeft(pc,y,y);
654: } else if (side == PC_SYMMETRIC) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot provide diagonal scaling with symmetric application of preconditioner");
655: } else {
656: if (pc->ops->applyBA) {
657: (*pc->ops->applyBA)(pc,side,x,y,work);
658: } else if (side == PC_RIGHT) {
659: PCApply(pc,x,work);
660: MatMult(pc->mat,work,y);
661: } else if (side == PC_LEFT) {
662: MatMult(pc->mat,x,work);
663: PCApply(pc,work,y);
664: } else if (side == PC_SYMMETRIC) {
665: /* There's an extra copy here; maybe should provide 2 work vectors instead? */
666: PCApplySymmetricRight(pc,x,work);
667: MatMult(pc->mat,work,y);
668: VecCopy(y,work);
669: PCApplySymmetricLeft(pc,work,y);
670: }
671: }
672: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
673: return(0);
674: }
676: /*@
677: PCApplyBAorABTranspose - Applies the transpose of the preconditioner
678: and operator to a vector. That is, applies tr(B) * tr(A) with left preconditioning,
679: NOT tr(B*A) = tr(A)*tr(B).
681: Collective on PC
683: Input Parameters:
684: + pc - the preconditioner context
685: . side - indicates the preconditioner side, one of PC_LEFT, PC_RIGHT, or PC_SYMMETRIC
686: . x - input vector
687: - work - work vector
689: Output Parameter:
690: . y - output vector
693: Notes:
694: 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
695: defined by B'. This is why this has the funny form that it computes tr(B) * tr(A)
697: Level: developer
699: .seealso: PCApply(), PCApplyTranspose(), PCApplyBAorAB()
700: @*/
701: PetscErrorCode PCApplyBAorABTranspose(PC pc,PCSide side,Vec x,Vec y,Vec work)
702: {
710: if (x == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"x and y must be different vectors");
711: if (pc->erroriffailure) {VecValidValues(x,3,PETSC_TRUE);}
712: if (pc->ops->applyBAtranspose) {
713: (*pc->ops->applyBAtranspose)(pc,side,x,y,work);
714: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
715: return(0);
716: }
717: if (side != PC_LEFT && side != PC_RIGHT) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Side must be right or left");
719: PCSetUp(pc);
720: if (side == PC_RIGHT) {
721: PCApplyTranspose(pc,x,work);
722: MatMultTranspose(pc->mat,work,y);
723: } else if (side == PC_LEFT) {
724: MatMultTranspose(pc->mat,x,work);
725: PCApplyTranspose(pc,work,y);
726: }
727: /* add support for PC_SYMMETRIC */
728: if (pc->erroriffailure) {VecValidValues(y,4,PETSC_FALSE);}
729: return(0);
730: }
732: /* -------------------------------------------------------------------------------*/
734: /*@
735: PCApplyRichardsonExists - Determines whether a particular preconditioner has a
736: built-in fast application of Richardson's method.
738: Not Collective
740: Input Parameter:
741: . pc - the preconditioner
743: Output Parameter:
744: . exists - PETSC_TRUE or PETSC_FALSE
746: Level: developer
748: .seealso: PCApplyRichardson()
749: @*/
750: PetscErrorCode PCApplyRichardsonExists(PC pc,PetscBool *exists)
751: {
755: if (pc->ops->applyrichardson) *exists = PETSC_TRUE;
756: else *exists = PETSC_FALSE;
757: return(0);
758: }
760: /*@
761: PCApplyRichardson - Applies several steps of Richardson iteration with
762: the particular preconditioner. This routine is usually used by the
763: Krylov solvers and not the application code directly.
765: Collective on PC
767: Input Parameters:
768: + pc - the preconditioner context
769: . b - the right hand side
770: . w - one work vector
771: . rtol - relative decrease in residual norm convergence criteria
772: . abstol - absolute residual norm convergence criteria
773: . dtol - divergence residual norm increase criteria
774: . its - the number of iterations to apply.
775: - guesszero - if the input x contains nonzero initial guess
777: Output Parameter:
778: + outits - number of iterations actually used (for SOR this always equals its)
779: . reason - the reason the apply terminated
780: - y - the solution (also contains initial guess if guesszero is PETSC_FALSE
782: Notes:
783: Most preconditioners do not support this function. Use the command
784: PCApplyRichardsonExists() to determine if one does.
786: Except for the multigrid PC this routine ignores the convergence tolerances
787: and always runs for the number of iterations
789: Level: developer
791: .seealso: PCApplyRichardsonExists()
792: @*/
793: PetscErrorCode PCApplyRichardson(PC pc,Vec b,Vec y,Vec w,PetscReal rtol,PetscReal abstol, PetscReal dtol,PetscInt its,PetscBool guesszero,PetscInt *outits,PCRichardsonConvergedReason *reason)
794: {
802: if (b == y) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_IDN,"b and y must be different vectors");
803: PCSetUp(pc);
804: if (!pc->ops->applyrichardson) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC does not have apply richardson");
805: (*pc->ops->applyrichardson)(pc,b,y,w,rtol,abstol,dtol,its,guesszero,outits,reason);
806: return(0);
807: }
809: /*@
810: PCGetFailedReason - Gets the reason a PCSetUp() failed or 0 if it did not fail
812: Logically Collective on PC
814: Input Parameter:
815: . pc - the preconditioner context
817: Output Parameter:
818: . reason - the reason it failed, currently only -1
820: Level: advanced
822: .seealso: PCCreate(), PCApply(), PCDestroy()
823: @*/
824: PetscErrorCode PCGetFailedReason(PC pc,PCFailedReason *reason)
825: {
827: if (pc->setupcalled < 0) *reason = (PCFailedReason)pc->setupcalled;
828: else *reason = pc->failedreason;
829: return(0);
830: }
833: /*
834: a setupcall of 0 indicates never setup,
835: 1 indicates has been previously setup
836: -1 indicates a PCSetUp() was attempted and failed
837: */
838: /*@
839: PCSetUp - Prepares for the use of a preconditioner.
841: Collective on PC
843: Input Parameter:
844: . pc - the preconditioner context
846: Level: developer
848: .seealso: PCCreate(), PCApply(), PCDestroy()
849: @*/
850: PetscErrorCode PCSetUp(PC pc)
851: {
852: PetscErrorCode ierr;
853: const char *def;
854: PetscObjectState matstate, matnonzerostate;
858: if (!pc->mat) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Matrix must be set first");
860: if (pc->setupcalled && pc->reusepreconditioner) {
861: PetscInfo(pc,"Leaving PC with identical preconditioner since reuse preconditioner is set\n");
862: return(0);
863: }
865: PetscObjectStateGet((PetscObject)pc->pmat,&matstate);
866: MatGetNonzeroState(pc->pmat,&matnonzerostate);
867: if (!pc->setupcalled) {
868: PetscInfo(pc,"Setting up PC for first time\n");
869: pc->flag = DIFFERENT_NONZERO_PATTERN;
870: } else if (matstate == pc->matstate) {
871: PetscInfo(pc,"Leaving PC with identical preconditioner since operator is unchanged\n");
872: return(0);
873: } else {
874: if (matnonzerostate > pc->matnonzerostate) {
875: PetscInfo(pc,"Setting up PC with different nonzero pattern\n");
876: pc->flag = DIFFERENT_NONZERO_PATTERN;
877: } else {
878: PetscInfo(pc,"Setting up PC with same nonzero pattern\n");
879: pc->flag = SAME_NONZERO_PATTERN;
880: }
881: }
882: pc->matstate = matstate;
883: pc->matnonzerostate = matnonzerostate;
885: if (!((PetscObject)pc)->type_name) {
886: PCGetDefaultType_Private(pc,&def);
887: PCSetType(pc,def);
888: }
890: MatSetErrorIfFailure(pc->pmat,pc->erroriffailure);
891: MatSetErrorIfFailure(pc->mat,pc->erroriffailure);
892: PetscLogEventBegin(PC_SetUp,pc,0,0,0);
893: if (pc->ops->setup) {
894: (*pc->ops->setup)(pc);
895: }
896: PetscLogEventEnd(PC_SetUp,pc,0,0,0);
897: if (!pc->setupcalled) pc->setupcalled = 1;
898: return(0);
899: }
901: /*@
902: PCSetUpOnBlocks - Sets up the preconditioner for each block in
903: the block Jacobi, block Gauss-Seidel, and overlapping Schwarz
904: methods.
906: Collective on PC
908: Input Parameters:
909: . pc - the preconditioner context
911: Level: developer
913: .seealso: PCCreate(), PCApply(), PCDestroy(), PCSetUp()
914: @*/
915: PetscErrorCode PCSetUpOnBlocks(PC pc)
916: {
921: if (!pc->ops->setuponblocks) return(0);
922: PetscLogEventBegin(PC_SetUpOnBlocks,pc,0,0,0);
923: (*pc->ops->setuponblocks)(pc);
924: PetscLogEventEnd(PC_SetUpOnBlocks,pc,0,0,0);
925: return(0);
926: }
928: /*@C
929: PCSetModifySubMatrices - Sets a user-defined routine for modifying the
930: submatrices that arise within certain subdomain-based preconditioners.
931: The basic submatrices are extracted from the preconditioner matrix as
932: usual; the user can then alter these (for example, to set different boundary
933: conditions for each submatrix) before they are used for the local solves.
935: Logically Collective on PC
937: Input Parameters:
938: + pc - the preconditioner context
939: . func - routine for modifying the submatrices
940: - ctx - optional user-defined context (may be null)
942: Calling sequence of func:
943: $ func (PC pc,PetscInt nsub,IS *row,IS *col,Mat *submat,void *ctx);
945: + row - an array of index sets that contain the global row numbers
946: that comprise each local submatrix
947: . col - an array of index sets that contain the global column numbers
948: that comprise each local submatrix
949: . submat - array of local submatrices
950: - ctx - optional user-defined context for private data for the
951: user-defined func routine (may be null)
953: Notes:
954: PCSetModifySubMatrices() MUST be called before KSPSetUp() and
955: KSPSolve().
957: A routine set by PCSetModifySubMatrices() is currently called within
958: the block Jacobi (PCBJACOBI) and additive Schwarz (PCASM)
959: preconditioners. All other preconditioners ignore this routine.
961: Level: advanced
963: .seealso: PCModifySubMatrices()
964: @*/
965: PetscErrorCode PCSetModifySubMatrices(PC pc,PetscErrorCode (*func)(PC,PetscInt,const IS[],const IS[],Mat[],void*),void *ctx)
966: {
969: pc->modifysubmatrices = func;
970: pc->modifysubmatricesP = ctx;
971: return(0);
972: }
974: /*@C
975: PCModifySubMatrices - Calls an optional user-defined routine within
976: certain preconditioners if one has been set with PCSetModifySubMatrices().
978: Collective on PC
980: Input Parameters:
981: + pc - the preconditioner context
982: . nsub - the number of local submatrices
983: . row - an array of index sets that contain the global row numbers
984: that comprise each local submatrix
985: . col - an array of index sets that contain the global column numbers
986: that comprise each local submatrix
987: . submat - array of local submatrices
988: - ctx - optional user-defined context for private data for the
989: user-defined routine (may be null)
991: Output Parameter:
992: . submat - array of local submatrices (the entries of which may
993: have been modified)
995: Notes:
996: The user should NOT generally call this routine, as it will
997: automatically be called within certain preconditioners (currently
998: block Jacobi, additive Schwarz) if set.
1000: The basic submatrices are extracted from the preconditioner matrix
1001: as usual; the user can then alter these (for example, to set different
1002: boundary conditions for each submatrix) before they are used for the
1003: local solves.
1005: Level: developer
1007: .seealso: PCSetModifySubMatrices()
1008: @*/
1009: PetscErrorCode PCModifySubMatrices(PC pc,PetscInt nsub,const IS row[],const IS col[],Mat submat[],void *ctx)
1010: {
1015: if (!pc->modifysubmatrices) return(0);
1016: PetscLogEventBegin(PC_ModifySubMatrices,pc,0,0,0);
1017: (*pc->modifysubmatrices)(pc,nsub,row,col,submat,ctx);
1018: PetscLogEventEnd(PC_ModifySubMatrices,pc,0,0,0);
1019: return(0);
1020: }
1022: /*@
1023: PCSetOperators - Sets the matrix associated with the linear system and
1024: a (possibly) different one associated with the preconditioner.
1026: Logically Collective on PC
1028: Input Parameters:
1029: + pc - the preconditioner context
1030: . Amat - the matrix that defines the linear system
1031: - Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
1033: Notes:
1034: Passing a NULL for Amat or Pmat removes the matrix that is currently used.
1036: If you wish to replace either Amat or Pmat but leave the other one untouched then
1037: first call KSPGetOperators() to get the one you wish to keep, call PetscObjectReference()
1038: on it and then pass it back in in your call to KSPSetOperators().
1040: More Notes about Repeated Solution of Linear Systems:
1041: PETSc does NOT reset the matrix entries of either Amat or Pmat
1042: to zero after a linear solve; the user is completely responsible for
1043: matrix assembly. See the routine MatZeroEntries() if desiring to
1044: zero all elements of a matrix.
1046: Level: intermediate
1048: .seealso: PCGetOperators(), MatZeroEntries()
1049: @*/
1050: PetscErrorCode PCSetOperators(PC pc,Mat Amat,Mat Pmat)
1051: {
1052: PetscErrorCode ierr;
1053: PetscInt m1,n1,m2,n2;
1061: if (pc->setupcalled && pc->mat && pc->pmat && Amat && Pmat) {
1062: MatGetLocalSize(Amat,&m1,&n1);
1063: MatGetLocalSize(pc->mat,&m2,&n2);
1064: 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);
1065: MatGetLocalSize(Pmat,&m1,&n1);
1066: MatGetLocalSize(pc->pmat,&m2,&n2);
1067: 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);
1068: }
1070: if (Pmat != pc->pmat) {
1071: /* changing the operator that defines the preconditioner thus reneed to clear current states so new preconditioner is built */
1072: pc->matnonzerostate = -1;
1073: pc->matstate = -1;
1074: }
1076: /* reference first in case the matrices are the same */
1077: if (Amat) {PetscObjectReference((PetscObject)Amat);}
1078: MatDestroy(&pc->mat);
1079: if (Pmat) {PetscObjectReference((PetscObject)Pmat);}
1080: MatDestroy(&pc->pmat);
1081: pc->mat = Amat;
1082: pc->pmat = Pmat;
1083: return(0);
1084: }
1086: /*@
1087: PCSetReusePreconditioner - reuse the current preconditioner even if the operator in the preconditioner has changed.
1089: Logically Collective on PC
1091: Input Parameters:
1092: + pc - the preconditioner context
1093: - flag - PETSC_TRUE do not compute a new preconditioner, PETSC_FALSE do compute a new preconditioner
1095: Level: intermediate
1097: .seealso: PCGetOperators(), MatZeroEntries(), PCGetReusePreconditioner(), KSPSetReusePreconditioner()
1098: @*/
1099: PetscErrorCode PCSetReusePreconditioner(PC pc,PetscBool flag)
1100: {
1103: pc->reusepreconditioner = flag;
1104: return(0);
1105: }
1107: /*@
1108: PCGetReusePreconditioner - Determines if the PC reuses the current preconditioner even if the operator in the preconditioner has changed.
1110: Not Collective
1112: Input Parameter:
1113: . pc - the preconditioner context
1115: Output Parameter:
1116: . flag - PETSC_TRUE do not compute a new preconditioner, PETSC_FALSE do compute a new preconditioner
1118: Level: intermediate
1120: .seealso: PCGetOperators(), MatZeroEntries(), PCSetReusePreconditioner()
1121: @*/
1122: PetscErrorCode PCGetReusePreconditioner(PC pc,PetscBool *flag)
1123: {
1126: *flag = pc->reusepreconditioner;
1127: return(0);
1128: }
1130: /*@
1131: PCGetOperators - Gets the matrix associated with the linear system and
1132: possibly a different one associated with the preconditioner.
1134: Not collective, though parallel Mats are returned if the PC is parallel
1136: Input Parameter:
1137: . pc - the preconditioner context
1139: Output Parameters:
1140: + Amat - the matrix defining the linear system
1141: - Pmat - the matrix from which the preconditioner is constructed, usually the same as Amat.
1143: Level: intermediate
1145: Notes:
1146: Does not increase the reference count of the matrices, so you should not destroy them
1148: Alternative usage: If the operators have NOT been set with KSP/PCSetOperators() then the operators
1149: are created in PC and returned to the user. In this case, if both operators
1150: mat and pmat are requested, two DIFFERENT operators will be returned. If
1151: only one is requested both operators in the PC will be the same (i.e. as
1152: if one had called KSP/PCSetOperators() with the same argument for both Mats).
1153: The user must set the sizes of the returned matrices and their type etc just
1154: as if the user created them with MatCreate(). For example,
1156: $ KSP/PCGetOperators(ksp/pc,&Amat,NULL); is equivalent to
1157: $ set size, type, etc of Amat
1159: $ MatCreate(comm,&mat);
1160: $ KSP/PCSetOperators(ksp/pc,Amat,Amat);
1161: $ PetscObjectDereference((PetscObject)mat);
1162: $ set size, type, etc of Amat
1164: and
1166: $ KSP/PCGetOperators(ksp/pc,&Amat,&Pmat); is equivalent to
1167: $ set size, type, etc of Amat and Pmat
1169: $ MatCreate(comm,&Amat);
1170: $ MatCreate(comm,&Pmat);
1171: $ KSP/PCSetOperators(ksp/pc,Amat,Pmat);
1172: $ PetscObjectDereference((PetscObject)Amat);
1173: $ PetscObjectDereference((PetscObject)Pmat);
1174: $ set size, type, etc of Amat and Pmat
1176: The rational for this support is so that when creating a TS, SNES, or KSP the hierarchy
1177: of underlying objects (i.e. SNES, KSP, PC, Mat) and their livespans can be completely
1178: managed by the top most level object (i.e. the TS, SNES, or KSP). Another way to look
1179: at this is when you create a SNES you do not NEED to create a KSP and attach it to
1180: the SNES object (the SNES object manages it for you). Similarly when you create a KSP
1181: you do not need to attach a PC to it (the KSP object manages the PC object for you).
1182: Thus, why should YOU have to create the Mat and attach it to the SNES/KSP/PC, when
1183: it can be created for you?
1186: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperatorsSet()
1187: @*/
1188: PetscErrorCode PCGetOperators(PC pc,Mat *Amat,Mat *Pmat)
1189: {
1194: if (Amat) {
1195: if (!pc->mat) {
1196: if (pc->pmat && !Pmat) { /* Apmat has been set, but user did not request it, so use for Amat */
1197: pc->mat = pc->pmat;
1198: PetscObjectReference((PetscObject)pc->mat);
1199: } else { /* both Amat and Pmat are empty */
1200: MatCreate(PetscObjectComm((PetscObject)pc),&pc->mat);
1201: if (!Pmat) { /* user did NOT request Pmat, so make same as Amat */
1202: pc->pmat = pc->mat;
1203: PetscObjectReference((PetscObject)pc->pmat);
1204: }
1205: }
1206: }
1207: *Amat = pc->mat;
1208: }
1209: if (Pmat) {
1210: if (!pc->pmat) {
1211: if (pc->mat && !Amat) { /* Amat has been set but was not requested, so use for pmat */
1212: pc->pmat = pc->mat;
1213: PetscObjectReference((PetscObject)pc->pmat);
1214: } else {
1215: MatCreate(PetscObjectComm((PetscObject)pc),&pc->pmat);
1216: if (!Amat) { /* user did NOT request Amat, so make same as Pmat */
1217: pc->mat = pc->pmat;
1218: PetscObjectReference((PetscObject)pc->mat);
1219: }
1220: }
1221: }
1222: *Pmat = pc->pmat;
1223: }
1224: return(0);
1225: }
1227: /*@C
1228: PCGetOperatorsSet - Determines if the matrix associated with the linear system and
1229: possibly a different one associated with the preconditioner have been set in the PC.
1231: Not collective, though the results on all processes should be the same
1233: Input Parameter:
1234: . pc - the preconditioner context
1236: Output Parameters:
1237: + mat - the matrix associated with the linear system was set
1238: - pmat - matrix associated with the preconditioner was set, usually the same
1240: Level: intermediate
1242: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperators()
1243: @*/
1244: PetscErrorCode PCGetOperatorsSet(PC pc,PetscBool *mat,PetscBool *pmat)
1245: {
1248: if (mat) *mat = (pc->mat) ? PETSC_TRUE : PETSC_FALSE;
1249: if (pmat) *pmat = (pc->pmat) ? PETSC_TRUE : PETSC_FALSE;
1250: return(0);
1251: }
1253: /*@
1254: PCFactorGetMatrix - Gets the factored matrix from the
1255: preconditioner context. This routine is valid only for the LU,
1256: incomplete LU, Cholesky, and incomplete Cholesky methods.
1258: Not Collective on PC though Mat is parallel if PC is parallel
1260: Input Parameters:
1261: . pc - the preconditioner context
1263: Output parameters:
1264: . mat - the factored matrix
1266: Level: advanced
1268: Notes:
1269: Does not increase the reference count for the matrix so DO NOT destroy it
1271: @*/
1272: PetscErrorCode PCFactorGetMatrix(PC pc,Mat *mat)
1273: {
1279: if (pc->ops->getfactoredmatrix) {
1280: (*pc->ops->getfactoredmatrix)(pc,mat);
1281: } else SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PC type does not support getting factor matrix");
1282: return(0);
1283: }
1285: /*@C
1286: PCSetOptionsPrefix - Sets the prefix used for searching for all
1287: PC options in the database.
1289: Logically Collective on PC
1291: Input Parameters:
1292: + pc - the preconditioner context
1293: - prefix - the prefix string to prepend to all PC option requests
1295: Notes:
1296: A hyphen (-) must NOT be given at the beginning of the prefix name.
1297: The first character of all runtime options is AUTOMATICALLY the
1298: hyphen.
1300: Level: advanced
1302: .seealso: PCAppendOptionsPrefix(), PCGetOptionsPrefix()
1303: @*/
1304: PetscErrorCode PCSetOptionsPrefix(PC pc,const char prefix[])
1305: {
1310: PetscObjectSetOptionsPrefix((PetscObject)pc,prefix);
1311: return(0);
1312: }
1314: /*@C
1315: PCAppendOptionsPrefix - Appends to the prefix used for searching for all
1316: PC options in the database.
1318: Logically Collective on PC
1320: Input Parameters:
1321: + pc - the preconditioner context
1322: - prefix - the prefix string to prepend to all PC option requests
1324: Notes:
1325: A hyphen (-) must NOT be given at the beginning of the prefix name.
1326: The first character of all runtime options is AUTOMATICALLY the
1327: hyphen.
1329: Level: advanced
1331: .seealso: PCSetOptionsPrefix(), PCGetOptionsPrefix()
1332: @*/
1333: PetscErrorCode PCAppendOptionsPrefix(PC pc,const char prefix[])
1334: {
1339: PetscObjectAppendOptionsPrefix((PetscObject)pc,prefix);
1340: return(0);
1341: }
1343: /*@C
1344: PCGetOptionsPrefix - Gets the prefix used for searching for all
1345: PC options in the database.
1347: Not Collective
1349: Input Parameters:
1350: . pc - the preconditioner context
1352: Output Parameters:
1353: . prefix - pointer to the prefix string used, is returned
1355: Notes:
1356: On the fortran side, the user should pass in a string 'prifix' of
1357: sufficient length to hold the prefix.
1359: Level: advanced
1361: .seealso: PCSetOptionsPrefix(), PCAppendOptionsPrefix()
1362: @*/
1363: PetscErrorCode PCGetOptionsPrefix(PC pc,const char *prefix[])
1364: {
1370: PetscObjectGetOptionsPrefix((PetscObject)pc,prefix);
1371: return(0);
1372: }
1374: /*
1375: Indicates the right hand side will be changed by KSPSolve(), this occurs for a few
1376: preconditioners including BDDC and Eisentat that transform the equations before applying
1377: the Krylov methods
1378: */
1379: PETSC_INTERN PetscErrorCode PCPreSolveChangeRHS(PC pc,PetscBool *change)
1380: {
1386: *change = PETSC_FALSE;
1387: PetscTryMethod(pc,"PCPreSolveChangeRHS_C",(PC,PetscBool*),(pc,change));
1388: return(0);
1389: }
1391: /*@
1392: PCPreSolve - Optional pre-solve phase, intended for any
1393: preconditioner-specific actions that must be performed before
1394: the iterative solve itself.
1396: Collective on PC
1398: Input Parameters:
1399: + pc - the preconditioner context
1400: - ksp - the Krylov subspace context
1402: Level: developer
1404: Sample of Usage:
1405: .vb
1406: PCPreSolve(pc,ksp);
1407: KSPSolve(ksp,b,x);
1408: PCPostSolve(pc,ksp);
1409: .ve
1411: Notes:
1412: The pre-solve phase is distinct from the PCSetUp() phase.
1414: KSPSolve() calls this directly, so is rarely called by the user.
1416: .seealso: PCPostSolve()
1417: @*/
1418: PetscErrorCode PCPreSolve(PC pc,KSP ksp)
1419: {
1421: Vec x,rhs;
1426: pc->presolvedone++;
1427: if (pc->presolvedone > 2) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot embed PCPreSolve() more than twice");
1428: KSPGetSolution(ksp,&x);
1429: KSPGetRhs(ksp,&rhs);
1431: if (pc->ops->presolve) {
1432: (*pc->ops->presolve)(pc,ksp,rhs,x);
1433: }
1434: return(0);
1435: }
1437: /*@
1438: PCPostSolve - Optional post-solve phase, intended for any
1439: preconditioner-specific actions that must be performed after
1440: the iterative solve itself.
1442: Collective on PC
1444: Input Parameters:
1445: + pc - the preconditioner context
1446: - ksp - the Krylov subspace context
1448: Sample of Usage:
1449: .vb
1450: PCPreSolve(pc,ksp);
1451: KSPSolve(ksp,b,x);
1452: PCPostSolve(pc,ksp);
1453: .ve
1455: Note:
1456: KSPSolve() calls this routine directly, so it is rarely called by the user.
1458: Level: developer
1460: .seealso: PCPreSolve(), KSPSolve()
1461: @*/
1462: PetscErrorCode PCPostSolve(PC pc,KSP ksp)
1463: {
1465: Vec x,rhs;
1470: pc->presolvedone--;
1471: KSPGetSolution(ksp,&x);
1472: KSPGetRhs(ksp,&rhs);
1473: if (pc->ops->postsolve) {
1474: (*pc->ops->postsolve)(pc,ksp,rhs,x);
1475: }
1476: return(0);
1477: }
1479: /*@C
1480: PCLoad - Loads a PC that has been stored in binary with PCView().
1482: Collective on PetscViewer
1484: Input Parameters:
1485: + newdm - the newly loaded PC, this needs to have been created with PCCreate() or
1486: some related function before a call to PCLoad().
1487: - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()
1489: Level: intermediate
1491: Notes:
1492: The type is determined by the data in the file, any type set into the PC before this call is ignored.
1494: Notes for advanced users:
1495: Most users should not need to know the details of the binary storage
1496: format, since PCLoad() and PCView() completely hide these details.
1497: But for anyone who's interested, the standard binary matrix storage
1498: format is
1499: .vb
1500: has not yet been determined
1501: .ve
1503: .seealso: PetscViewerBinaryOpen(), PCView(), MatLoad(), VecLoad()
1504: @*/
1505: PetscErrorCode PCLoad(PC newdm, PetscViewer viewer)
1506: {
1508: PetscBool isbinary;
1509: PetscInt classid;
1510: char type[256];
1515: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
1516: if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1518: PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
1519: if (classid != PC_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)newdm),PETSC_ERR_ARG_WRONG,"Not PC next in file");
1520: PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
1521: PCSetType(newdm, type);
1522: if (newdm->ops->load) {
1523: (*newdm->ops->load)(newdm,viewer);
1524: }
1525: return(0);
1526: }
1528: #include <petscdraw.h>
1529: #if defined(PETSC_HAVE_SAWS)
1530: #include <petscviewersaws.h>
1531: #endif
1532: /*@C
1533: PCView - Prints the PC data structure.
1535: Collective on PC
1537: Input Parameters:
1538: + PC - the PC context
1539: - viewer - optional visualization context
1541: Note:
1542: The available visualization contexts include
1543: + PETSC_VIEWER_STDOUT_SELF - standard output (default)
1544: - PETSC_VIEWER_STDOUT_WORLD - synchronized standard
1545: output where only the first processor opens
1546: the file. All other processors send their
1547: data to the first processor to print.
1549: The user can open an alternative visualization contexts with
1550: PetscViewerASCIIOpen() (output to a specified file).
1552: Level: developer
1554: .seealso: KSPView(), PetscViewerASCIIOpen()
1555: @*/
1556: PetscErrorCode PCView(PC pc,PetscViewer viewer)
1557: {
1558: PCType cstr;
1560: PetscBool iascii,isstring,isbinary,isdraw;
1561: #if defined(PETSC_HAVE_SAWS)
1562: PetscBool issaws;
1563: #endif
1567: if (!viewer) {
1568: PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)pc),&viewer);
1569: }
1573: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
1574: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
1575: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
1576: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
1577: #if defined(PETSC_HAVE_SAWS)
1578: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
1579: #endif
1581: if (iascii) {
1582: PetscObjectPrintClassNamePrefixType((PetscObject)pc,viewer);
1583: if (!pc->setupcalled) {
1584: PetscViewerASCIIPrintf(viewer," PC has not been set up so information may be incomplete\n");
1585: }
1586: if (pc->ops->view) {
1587: PetscViewerASCIIPushTab(viewer);
1588: (*pc->ops->view)(pc,viewer);
1589: PetscViewerASCIIPopTab(viewer);
1590: }
1591: if (pc->mat) {
1592: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO);
1593: if (pc->pmat == pc->mat) {
1594: PetscViewerASCIIPrintf(viewer," linear system matrix = precond matrix:\n");
1595: PetscViewerASCIIPushTab(viewer);
1596: MatView(pc->mat,viewer);
1597: PetscViewerASCIIPopTab(viewer);
1598: } else {
1599: if (pc->pmat) {
1600: PetscViewerASCIIPrintf(viewer," linear system matrix followed by preconditioner matrix:\n");
1601: } else {
1602: PetscViewerASCIIPrintf(viewer," linear system matrix:\n");
1603: }
1604: PetscViewerASCIIPushTab(viewer);
1605: MatView(pc->mat,viewer);
1606: if (pc->pmat) {MatView(pc->pmat,viewer);}
1607: PetscViewerASCIIPopTab(viewer);
1608: }
1609: PetscViewerPopFormat(viewer);
1610: }
1611: } else if (isstring) {
1612: PCGetType(pc,&cstr);
1613: PetscViewerStringSPrintf(viewer," PCType: %-7.7s",cstr);
1614: if (pc->ops->view) {(*pc->ops->view)(pc,viewer);}
1615: if (pc->mat) {MatView(pc->mat,viewer);}
1616: if (pc->pmat && pc->pmat != pc->mat) {MatView(pc->pmat,viewer);}
1617: } else if (isbinary) {
1618: PetscInt classid = PC_FILE_CLASSID;
1619: MPI_Comm comm;
1620: PetscMPIInt rank;
1621: char type[256];
1623: PetscObjectGetComm((PetscObject)pc,&comm);
1624: MPI_Comm_rank(comm,&rank);
1625: if (!rank) {
1626: PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);
1627: PetscStrncpy(type,((PetscObject)pc)->type_name,256);
1628: PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR,PETSC_FALSE);
1629: }
1630: if (pc->ops->view) {
1631: (*pc->ops->view)(pc,viewer);
1632: }
1633: } else if (isdraw) {
1634: PetscDraw draw;
1635: char str[25];
1636: PetscReal x,y,bottom,h;
1637: PetscInt n;
1639: PetscViewerDrawGetDraw(viewer,0,&draw);
1640: PetscDrawGetCurrentPoint(draw,&x,&y);
1641: if (pc->mat) {
1642: MatGetSize(pc->mat,&n,NULL);
1643: PetscSNPrintf(str,25,"PC: %s (%D)",((PetscObject)pc)->type_name,n);
1644: } else {
1645: PetscSNPrintf(str,25,"PC: %s",((PetscObject)pc)->type_name);
1646: }
1647: PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);
1648: bottom = y - h;
1649: PetscDrawPushCurrentPoint(draw,x,bottom);
1650: if (pc->ops->view) {
1651: (*pc->ops->view)(pc,viewer);
1652: }
1653: PetscDrawPopCurrentPoint(draw);
1654: #if defined(PETSC_HAVE_SAWS)
1655: } else if (issaws) {
1656: PetscMPIInt rank;
1658: PetscObjectName((PetscObject)pc);
1659: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
1660: if (!((PetscObject)pc)->amsmem && !rank) {
1661: PetscObjectViewSAWs((PetscObject)pc,viewer);
1662: }
1663: if (pc->mat) {MatView(pc->mat,viewer);}
1664: if (pc->pmat && pc->pmat != pc->mat) {MatView(pc->pmat,viewer);}
1665: #endif
1666: }
1667: return(0);
1668: }
1670: /*@C
1671: PCRegister - Adds a method to the preconditioner package.
1673: Not collective
1675: Input Parameters:
1676: + name_solver - name of a new user-defined solver
1677: - routine_create - routine to create method context
1679: Notes:
1680: PCRegister() may be called multiple times to add several user-defined preconditioners.
1682: Sample usage:
1683: .vb
1684: PCRegister("my_solver", MySolverCreate);
1685: .ve
1687: Then, your solver can be chosen with the procedural interface via
1688: $ PCSetType(pc,"my_solver")
1689: or at runtime via the option
1690: $ -pc_type my_solver
1692: Level: advanced
1694: .seealso: PCRegisterAll()
1695: @*/
1696: PetscErrorCode PCRegister(const char sname[],PetscErrorCode (*function)(PC))
1697: {
1701: PCInitializePackage();
1702: PetscFunctionListAdd(&PCList,sname,function);
1703: return(0);
1704: }
1706: static PetscErrorCode MatMult_PC(Mat A,Vec X,Vec Y)
1707: {
1708: PC pc;
1712: MatShellGetContext(A,&pc);
1713: PCApply(pc,X,Y);
1714: return(0);
1715: }
1717: /*@
1718: PCComputeOperator - Computes the explicit preconditioned operator.
1720: Collective on PC
1722: Input Parameter:
1723: + pc - the preconditioner object
1724: - mattype - the matrix type to be used for the operator
1726: Output Parameter:
1727: . mat - the explict preconditioned operator
1729: Notes:
1730: This computation is done by applying the operators to columns of the identity matrix.
1731: This routine is costly in general, and is recommended for use only with relatively small systems.
1732: Currently, this routine uses a dense matrix format when mattype == NULL
1734: Level: advanced
1736: .seealso: KSPComputeOperator(), MatType
1738: @*/
1739: PetscErrorCode PCComputeOperator(PC pc,MatType mattype,Mat *mat)
1740: {
1742: PetscInt N,M,m,n;
1743: Mat A,Apc;
1748: PCGetOperators(pc,&A,NULL);
1749: MatGetLocalSize(A,&m,&n);
1750: MatGetSize(A,&M,&N);
1751: MatCreateShell(PetscObjectComm((PetscObject)pc),m,n,M,N,pc,&Apc);
1752: MatShellSetOperation(Apc,MATOP_MULT,(void (*)(void))MatMult_PC);
1753: MatComputeOperator(Apc,mattype,mat);
1754: MatDestroy(&Apc);
1755: return(0);
1756: }
1758: /*@
1759: PCSetCoordinates - sets the coordinates of all the nodes on the local process
1761: Collective on PC
1763: Input Parameters:
1764: + pc - the solver context
1765: . dim - the dimension of the coordinates 1, 2, or 3
1766: . nloc - the blocked size of the coordinates array
1767: - coords - the coordinates array
1769: Level: intermediate
1771: Notes:
1772: coords is an array of the dim coordinates for the nodes on
1773: the local processor, of size dim*nloc.
1774: If there are 108 equation on a processor
1775: for a displacement finite element discretization of elasticity (so
1776: that there are nloc = 36 = 108/3 nodes) then the array must have 108
1777: double precision values (ie, 3 * 36). These x y z coordinates
1778: should be ordered for nodes 0 to N-1 like so: [ 0.x, 0.y, 0.z, 1.x,
1779: ... , N-1.z ].
1781: .seealso: MatSetNearNullSpace()
1782: @*/
1783: PetscErrorCode PCSetCoordinates(PC pc, PetscInt dim, PetscInt nloc, PetscReal coords[])
1784: {
1790: PetscTryMethod(pc,"PCSetCoordinates_C",(PC,PetscInt,PetscInt,PetscReal*),(pc,dim,nloc,coords));
1791: return(0);
1792: }
1794: /*@
1795: PCGetInterpolations - Gets interpolation matrices for all levels (except level 0)
1797: Logically Collective on PC
1799: Input Parameters:
1800: + pc - the precondition context
1802: Output Parameter:
1803: - num_levels - the number of levels
1804: . interpolations - the interpolation matrices (size of num_levels-1)
1806: Level: advanced
1808: .keywords: MG, GAMG, BoomerAMG, multigrid, interpolation, level
1810: .seealso: PCMGGetRestriction(), PCMGSetInterpolation(), PCMGGetInterpolation(), PCGetCoarseOperators()
1811: @*/
1812: PetscErrorCode PCGetInterpolations(PC pc,PetscInt *num_levels,Mat *interpolations[])
1813: {
1820: PetscUseMethod(pc,"PCGetInterpolations_C",(PC,PetscInt*,Mat*[]),(pc,num_levels,interpolations));
1821: return(0);
1822: }
1824: /*@
1825: PCGetCoarseOperators - Gets coarse operator matrices for all levels (except the finest level)
1827: Logically Collective on PC
1829: Input Parameters:
1830: + pc - the precondition context
1832: Output Parameter:
1833: - num_levels - the number of levels
1834: . coarseOperators - the coarse operator matrices (size of num_levels-1)
1836: Level: advanced
1838: .keywords: MG, GAMG, BoomerAMG, get, multigrid, interpolation, level
1840: .seealso: PCMGGetRestriction(), PCMGSetInterpolation(), PCMGGetRScale(), PCMGGetInterpolation(), PCGetInterpolations()
1841: @*/
1842: PetscErrorCode PCGetCoarseOperators(PC pc,PetscInt *num_levels,Mat *coarseOperators[])
1843: {
1850: PetscUseMethod(pc,"PCGetCoarseOperators_C",(PC,PetscInt*,Mat*[]),(pc,num_levels,coarseOperators));
1851: return(0);
1852: }