Actual source code: iterativ.c
petsc-master 2019-06-19
1: /*
2: This file contains some simple default routines.
3: These routines should be SHORT, since they will be included in every
4: executable image that uses the iterative routines (note that, through
5: the registry system, we provide a way to load only the truely necessary
6: files)
7: */
8: #include <petsc/private/kspimpl.h>
9: #include <petscdmshell.h>
11: /*@
12: KSPGetResidualNorm - Gets the last (approximate preconditioned)
13: residual norm that has been computed.
15: Not Collective
17: Input Parameters:
18: . ksp - the iterative context
20: Output Parameters:
21: . rnorm - residual norm
23: Level: intermediate
25: .seealso: KSPBuildResidual()
26: @*/
27: PetscErrorCode KSPGetResidualNorm(KSP ksp,PetscReal *rnorm)
28: {
32: *rnorm = ksp->rnorm;
33: return(0);
34: }
36: /*@
37: KSPGetIterationNumber - Gets the current iteration number; if the
38: KSPSolve() is complete, returns the number of iterations
39: used.
41: Not Collective
43: Input Parameters:
44: . ksp - the iterative context
46: Output Parameters:
47: . its - number of iterations
49: Level: intermediate
51: Notes:
52: During the ith iteration this returns i-1
53: .seealso: KSPBuildResidual(), KSPGetResidualNorm(), KSPGetTotalIterations()
54: @*/
55: PetscErrorCode KSPGetIterationNumber(KSP ksp,PetscInt *its)
56: {
60: *its = ksp->its;
61: return(0);
62: }
64: /*@
65: KSPGetTotalIterations - Gets the total number of iterations this KSP object has performed since was created, counted over all linear solves
67: Not Collective
69: Input Parameters:
70: . ksp - the iterative context
72: Output Parameters:
73: . its - total number of iterations
75: Level: intermediate
77: Notes:
78: Use KSPGetIterationNumber() to get the count for the most recent solve only
79: If this is called within a linear solve (such as in a KSPMonitor routine) then it does not include iterations within that current solve
81: .seealso: KSPBuildResidual(), KSPGetResidualNorm(), KSPGetIterationNumber()
82: @*/
83: PetscErrorCode KSPGetTotalIterations(KSP ksp,PetscInt *its)
84: {
88: *its = ksp->totalits;
89: return(0);
90: }
92: /*@C
93: KSPMonitorSingularValue - Prints the two norm of the true residual and
94: estimation of the extreme singular values of the preconditioned problem
95: at each iteration.
97: Logically Collective on ksp
99: Input Parameters:
100: + ksp - the iterative context
101: . n - the iteration
102: - rnorm - the two norm of the residual
104: Options Database Key:
105: . -ksp_monitor_singular_value - Activates KSPMonitorSingularValue()
107: Notes:
108: The CG solver uses the Lanczos technique for eigenvalue computation,
109: while GMRES uses the Arnoldi technique; other iterative methods do
110: not currently compute singular values.
112: Level: intermediate
114: .seealso: KSPComputeExtremeSingularValues()
115: @*/
116: PetscErrorCode KSPMonitorSingularValue(KSP ksp,PetscInt n,PetscReal rnorm,PetscViewerAndFormat *dummy)
117: {
118: PetscReal emin,emax,c;
120: PetscViewer viewer = dummy->viewer;
125: PetscViewerPushFormat(viewer,dummy->format);
126: PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
127: if (!ksp->calc_sings) {
128: PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %14.12e \n",n,(double)rnorm);
129: } else {
130: KSPComputeExtremeSingularValues(ksp,&emax,&emin);
131: c = emax/emin;
132: PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %14.12e %% max %14.12e min %14.12e max/min %14.12e\n",n,(double)rnorm,(double)emax,(double)emin,(double)c);
133: }
134: PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
135: PetscViewerPopFormat(viewer);
136: return(0);
137: }
139: /*@C
140: KSPMonitorSolution - Monitors progress of the KSP solvers by calling
141: VecView() for the approximate solution at each iteration.
143: Collective on ksp
145: Input Parameters:
146: + ksp - the KSP context
147: . its - iteration number
148: . fgnorm - 2-norm of residual (or gradient)
149: - dummy - a viewer
151: Level: intermediate
153: Notes:
154: For some Krylov methods such as GMRES constructing the solution at
155: each iteration is expensive, hence using this will slow the code.
157: .seealso: KSPMonitorSet(), KSPMonitorDefault(), VecView()
158: @*/
159: PetscErrorCode KSPMonitorSolution(KSP ksp,PetscInt its,PetscReal fgnorm,PetscViewerAndFormat *dummy)
160: {
162: Vec x;
163: PetscViewer viewer = dummy->viewer;
167: KSPBuildSolution(ksp,NULL,&x);
168: PetscViewerPushFormat(viewer,dummy->format);
169: VecView(x,viewer);
170: PetscViewerPopFormat(viewer);
171: return(0);
172: }
174: /*@C
175: KSPMonitorDefault - Print the residual norm at each iteration of an
176: iterative solver.
178: Collective on ksp
180: Input Parameters:
181: + ksp - iterative context
182: . n - iteration number
183: . rnorm - 2-norm (preconditioned) residual value (may be estimated).
184: - dummy - an ASCII PetscViewer
186: Level: intermediate
188: .seealso: KSPMonitorSet(), KSPMonitorTrueResidualNorm(), KSPMonitorLGResidualNormCreate()
189: @*/
190: PetscErrorCode KSPMonitorDefault(KSP ksp,PetscInt n,PetscReal rnorm,PetscViewerAndFormat *dummy)
191: {
193: PetscViewer viewer = dummy->viewer;
197: PetscViewerPushFormat(viewer,dummy->format);
198: PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
199: if (n == 0 && ((PetscObject)ksp)->prefix) {
200: PetscViewerASCIIPrintf(viewer," Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);
201: }
202: PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %14.12e \n",n,(double)rnorm);
203: PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
204: PetscViewerPopFormat(viewer);
205: return(0);
206: }
208: /*@C
209: KSPMonitorTrueResidualNorm - Prints the true residual norm as well as the preconditioned
210: residual norm at each iteration of an iterative solver.
212: Collective on ksp
214: Input Parameters:
215: + ksp - iterative context
216: . n - iteration number
217: . rnorm - 2-norm (preconditioned) residual value (may be estimated).
218: - dummy - an ASCII PetscViewer
220: Options Database Key:
221: . -ksp_monitor_true_residual - Activates KSPMonitorTrueResidualNorm()
223: Notes:
224: When using right preconditioning, these values are equivalent.
226: Level: intermediate
228: .seealso: KSPMonitorSet(), KSPMonitorDefault(), KSPMonitorLGResidualNormCreate(),KSPMonitorTrueResidualMaxNorm()
229: @*/
230: PetscErrorCode KSPMonitorTrueResidualNorm(KSP ksp,PetscInt n,PetscReal rnorm,PetscViewerAndFormat *dummy)
231: {
233: Vec resid;
234: PetscReal truenorm,bnorm;
235: PetscViewer viewer = dummy->viewer;
236: char normtype[256];
240: PetscViewerPushFormat(viewer,dummy->format);
241: PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
242: if (n == 0 && ((PetscObject)ksp)->prefix) {
243: PetscViewerASCIIPrintf(viewer," Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);
244: }
245: KSPBuildResidual(ksp,NULL,NULL,&resid);
246: VecNorm(resid,NORM_2,&truenorm);
247: VecDestroy(&resid);
248: VecNorm(ksp->vec_rhs,NORM_2,&bnorm);
249: PetscStrncpy(normtype,KSPNormTypes[ksp->normtype],sizeof(normtype));
250: PetscStrtolower(normtype);
251: PetscViewerASCIIPrintf(viewer,"%3D KSP %s resid norm %14.12e true resid norm %14.12e ||r(i)||/||b|| %14.12e\n",n,normtype,(double)rnorm,(double)truenorm,(double)(truenorm/bnorm));
252: PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
253: PetscViewerPopFormat(viewer);
254: return(0);
255: }
257: /*@C
258: KSPMonitorTrueResidualMaxNorm - Prints the true residual max norm each iteration of an iterative solver.
260: Collective on ksp
262: Input Parameters:
263: + ksp - iterative context
264: . n - iteration number
265: . rnorm - norm (preconditioned) residual value (may be estimated).
266: - dummy - an ASCII viewer
268: Options Database Key:
269: . -ksp_monitor_max - Activates KSPMonitorTrueResidualMaxNorm()
271: Notes:
272: This could be implemented (better) with a flag in ksp.
274: Level: intermediate
276: .seealso: KSPMonitorSet(), KSPMonitorDefault(), KSPMonitorLGResidualNormCreate(),KSPMonitorTrueResidualNorm()
277: @*/
278: PetscErrorCode KSPMonitorTrueResidualMaxNorm(KSP ksp,PetscInt n,PetscReal rnorm,PetscViewerAndFormat *dummy)
279: {
281: Vec resid;
282: PetscReal truenorm,bnorm;
283: PetscViewer viewer = dummy->viewer;
284: char normtype[256];
288: PetscViewerPushFormat(viewer,dummy->format);
289: PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
290: if (n == 0 && ((PetscObject)ksp)->prefix) {
291: PetscViewerASCIIPrintf(viewer," Residual norms (max) for %s solve.\n",((PetscObject)ksp)->prefix);
292: }
293: KSPBuildResidual(ksp,NULL,NULL,&resid);
294: VecNorm(resid,NORM_INFINITY,&truenorm);
295: VecDestroy(&resid);
296: VecNorm(ksp->vec_rhs,NORM_INFINITY,&bnorm);
297: PetscStrncpy(normtype,KSPNormTypes[ksp->normtype],sizeof(normtype));
298: PetscStrtolower(normtype);
299: PetscViewerASCIIPrintf(viewer,"%3D KSP true resid max norm %14.12e ||r(i)||/||b|| %14.12e\n",n,(double)truenorm,(double)(truenorm/bnorm));
300: PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
301: PetscViewerPopFormat(viewer);
302: return(0);
303: }
305: PetscErrorCode KSPMonitorRange_Private(KSP ksp,PetscInt it,PetscReal *per)
306: {
308: Vec resid;
309: PetscReal rmax,pwork;
310: PetscInt i,n,N;
311: const PetscScalar *r;
314: KSPBuildResidual(ksp,NULL,NULL,&resid);
315: VecNorm(resid,NORM_INFINITY,&rmax);
316: VecGetLocalSize(resid,&n);
317: VecGetSize(resid,&N);
318: VecGetArrayRead(resid,&r);
319: pwork = 0.0;
320: for (i=0; i<n; i++) pwork += (PetscAbsScalar(r[i]) > .20*rmax);
321: VecRestoreArrayRead(resid,&r);
322: VecDestroy(&resid);
323: MPIU_Allreduce(&pwork,per,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)ksp));
324: *per = *per/N;
325: return(0);
326: }
328: /*@C
329: KSPMonitorRange - Prints the percentage of residual elements that are more then 10 percent of the maximum value.
331: Collective on ksp
333: Input Parameters:
334: + ksp - iterative context
335: . it - iteration number
336: . rnorm - 2-norm (preconditioned) residual value (may be estimated).
337: - dummy - an ASCII viewer
339: Options Database Key:
340: . -ksp_monitor_range - Activates KSPMonitorRange()
342: Level: intermediate
344: .seealso: KSPMonitorSet(), KSPMonitorDefault(), KSPMonitorLGResidualNormCreate()
345: @*/
346: PetscErrorCode KSPMonitorRange(KSP ksp,PetscInt it,PetscReal rnorm,PetscViewerAndFormat *dummy)
347: {
348: PetscErrorCode ierr;
349: PetscReal perc,rel;
350: PetscViewer viewer = dummy->viewer;
351: /* should be in a MonitorRangeContext */
352: static PetscReal prev;
356: PetscViewerPushFormat(viewer,dummy->format);
357: PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
358: if (!it) prev = rnorm;
359: if (it == 0 && ((PetscObject)ksp)->prefix) {
360: PetscViewerASCIIPrintf(viewer," Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);
361: }
362: KSPMonitorRange_Private(ksp,it,&perc);
364: rel = (prev - rnorm)/prev;
365: prev = rnorm;
366: PetscViewerASCIIPrintf(viewer,"%3D KSP preconditioned resid norm %14.12e Percent values above 20 percent of maximum %5.2f relative decrease %5.2e ratio %5.2e \n",it,(double)rnorm,(double)(100.0*perc),(double)rel,(double)(rel/perc));
367: PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
368: PetscViewerPopFormat(viewer);
369: return(0);
370: }
372: /*@C
373: KSPMonitorDynamicTolerance - Recompute the inner tolerance in every
374: outer iteration in an adaptive way.
376: Collective on ksp
378: Input Parameters:
379: + ksp - iterative context
380: . n - iteration number (not used)
381: . fnorm - the current residual norm
382: . dummy - some context as a C struct. fields:
383: coef: a scaling coefficient. default 1.0. can be passed through
384: -sub_ksp_dynamic_tolerance_param
385: bnrm: norm of the right-hand side. store it to avoid repeated calculation
387: Notes:
388: This may be useful for a flexibly preconditioner Krylov method to
389: control the accuracy of the inner solves needed to gaurantee the
390: convergence of the outer iterations.
392: Level: advanced
394: .seealso: KSPMonitorDynamicToleranceDestroy()
395: @*/
396: PetscErrorCode KSPMonitorDynamicTolerance(KSP ksp,PetscInt its,PetscReal fnorm,void *dummy)
397: {
399: PC pc;
400: PetscReal outer_rtol, outer_abstol, outer_dtol, inner_rtol;
401: PetscInt outer_maxits,nksp,first,i;
402: KSPDynTolCtx *scale = (KSPDynTolCtx*)dummy;
403: KSP *subksp = NULL;
404: PetscBool isksp;
407: KSPGetPC(ksp, &pc);
409: /* compute inner_rtol */
410: if (scale->bnrm < 0.0) {
411: Vec b;
412: KSPGetRhs(ksp, &b);
413: VecNorm(b, NORM_2, &(scale->bnrm));
414: }
415: KSPGetTolerances(ksp, &outer_rtol, &outer_abstol, &outer_dtol, &outer_maxits);
416: inner_rtol = PetscMin(scale->coef * scale->bnrm * outer_rtol / fnorm, 0.999);
417: /*PetscPrintf(PETSC_COMM_WORLD, " Inner rtol = %g\n", (double)inner_rtol);*/
419: /* if pc is ksp */
420: PetscObjectTypeCompare((PetscObject)pc,PCKSP,&isksp);
421: if (isksp) {
422: KSP kspinner;
424: PCKSPGetKSP(pc, &kspinner);
425: KSPSetTolerances(kspinner, inner_rtol, outer_abstol, outer_dtol, outer_maxits);
426: return(0);
427: }
429: /* if pc is bjacobi */
430: PCBJacobiGetSubKSP(pc, &nksp, &first, &subksp);
431: if (subksp) {
432: for (i=0; i<nksp; i++) {
433: KSPSetTolerances(subksp[i], inner_rtol, outer_abstol, outer_dtol, outer_maxits);
434: }
435: return(0);
436: }
438: /* todo: dynamic tolerance may apply to other types of pc too */
439: return(0);
440: }
442: /*
443: Destroy the dummy context used in KSPMonitorDynamicTolerance()
444: */
445: PetscErrorCode KSPMonitorDynamicToleranceDestroy(void **dummy)
446: {
450: PetscFree(*dummy);
451: return(0);
452: }
454: /*
455: Default (short) KSP Monitor, same as KSPMonitorDefault() except
456: it prints fewer digits of the residual as the residual gets smaller.
457: This is because the later digits are meaningless and are often
458: different on different machines; by using this routine different
459: machines will usually generate the same output.
461: Deprecated: Intentionally has no manual page
462: */
463: PetscErrorCode KSPMonitorDefaultShort(KSP ksp,PetscInt its,PetscReal fnorm,PetscViewerAndFormat *dummy)
464: {
466: PetscViewer viewer = dummy->viewer;
470: PetscViewerPushFormat(viewer,dummy->format);
471: PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
472: if (its == 0 && ((PetscObject)ksp)->prefix) {
473: PetscViewerASCIIPrintf(viewer," Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);
474: }
476: if (fnorm > 1.e-9) {
477: PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %g \n",its,(double)fnorm);
478: } else if (fnorm > 1.e-11) {
479: PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %5.3e \n",its,(double)fnorm);
480: } else {
481: PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm < 1.e-11\n",its);
482: }
483: PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
484: PetscViewerPopFormat(viewer);
485: return(0);
486: }
488: /*@C
489: KSPConvergedSkip - Convergence test that do not return as converged
490: until the maximum number of iterations is reached.
492: Collective on ksp
494: Input Parameters:
495: + ksp - iterative context
496: . n - iteration number
497: . rnorm - 2-norm residual value (may be estimated)
498: - dummy - unused convergence context
500: Returns:
501: . reason - KSP_CONVERGED_ITERATING, KSP_CONVERGED_ITS
503: Notes:
504: This should be used as the convergence test with the option
505: KSPSetNormType(ksp,KSP_NORM_NONE), since norms of the residual are
506: not computed. Convergence is then declared after the maximum number
507: of iterations have been reached. Useful when one is using CG or
508: BiCGStab as a smoother.
510: Level: advanced
512: .seealso: KSPSetConvergenceTest(), KSPSetTolerances(), KSPSetNormType()
513: @*/
514: PetscErrorCode KSPConvergedSkip(KSP ksp,PetscInt n,PetscReal rnorm,KSPConvergedReason *reason,void *dummy)
515: {
519: *reason = KSP_CONVERGED_ITERATING;
520: if (n >= ksp->max_it) *reason = KSP_CONVERGED_ITS;
521: return(0);
522: }
525: /*@C
526: KSPConvergedDefaultCreate - Creates and initializes the space used by the KSPConvergedDefault() function context
528: Note Collective
530: Output Parameter:
531: . ctx - convergence context
533: Level: intermediate
535: .seealso: KSPConvergedDefault(), KSPConvergedDefaultDestroy(), KSPSetConvergenceTest(), KSPSetTolerances(),
536: KSPConvergedSkip(), KSPConvergedReason, KSPGetConvergedReason(), KSPConvergedDefaultSetUIRNorm(), KSPConvergedDefaultSetUMIRNorm()
537: @*/
538: PetscErrorCode KSPConvergedDefaultCreate(void **ctx)
539: {
540: PetscErrorCode ierr;
541: KSPConvergedDefaultCtx *cctx;
544: PetscNew(&cctx);
545: *ctx = cctx;
546: return(0);
547: }
549: /*@
550: KSPConvergedDefaultSetUIRNorm - makes the default convergence test use || B*(b - A*(initial guess))||
551: instead of || B*b ||. In the case of right preconditioner or if KSPSetNormType(ksp,KSP_NORM_UNPRECONDIITONED)
552: is used there is no B in the above formula. UIRNorm is short for Use Initial Residual Norm.
554: Collective on ksp
556: Input Parameters:
557: . ksp - iterative context
559: Options Database:
560: . -ksp_converged_use_initial_residual_norm
562: Notes:
563: Use KSPSetTolerances() to alter the defaults for rtol, abstol, dtol.
565: The precise values of reason are macros such as KSP_CONVERGED_RTOL, which
566: are defined in petscksp.h.
568: If the convergence test is not KSPConvergedDefault() then this is ignored.
570: If right preconditioning is being used then B does not appear in the above formula.
573: Level: intermediate
575: .seealso: KSPSetConvergenceTest(), KSPSetTolerances(), KSPConvergedSkip(), KSPConvergedReason, KSPGetConvergedReason(), KSPConvergedDefaultSetUMIRNorm()
576: @*/
577: PetscErrorCode KSPConvergedDefaultSetUIRNorm(KSP ksp)
578: {
579: KSPConvergedDefaultCtx *ctx = (KSPConvergedDefaultCtx*) ksp->cnvP;
583: if (ksp->converged != KSPConvergedDefault) return(0);
584: if (ctx->mininitialrtol) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_WRONGSTATE,"Cannot use KSPConvergedDefaultSetUIRNorm() and KSPConvergedDefaultSetUMIRNorm() together");
585: ctx->initialrtol = PETSC_TRUE;
586: return(0);
587: }
589: /*@
590: KSPConvergedDefaultSetUMIRNorm - makes the default convergence test use min(|| B*(b - A*(initial guess))||,|| B*b ||)
591: In the case of right preconditioner or if KSPSetNormType(ksp,KSP_NORM_UNPRECONDIITONED)
592: is used there is no B in the above formula. UMIRNorm is short for Use Minimum Initial Residual Norm.
594: Collective on ksp
596: Input Parameters:
597: . ksp - iterative context
599: Options Database:
600: . -ksp_converged_use_min_initial_residual_norm
602: Use KSPSetTolerances() to alter the defaults for rtol, abstol, dtol.
604: The precise values of reason are macros such as KSP_CONVERGED_RTOL, which
605: are defined in petscksp.h.
607: Level: intermediate
609: .seealso: KSPSetConvergenceTest(), KSPSetTolerances(), KSPConvergedSkip(), KSPConvergedReason, KSPGetConvergedReason(), KSPConvergedDefaultSetUIRNorm()
610: @*/
611: PetscErrorCode KSPConvergedDefaultSetUMIRNorm(KSP ksp)
612: {
613: KSPConvergedDefaultCtx *ctx = (KSPConvergedDefaultCtx*) ksp->cnvP;
617: if (ksp->converged != KSPConvergedDefault) return(0);
618: if (ctx->initialrtol) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_WRONGSTATE,"Cannot use KSPConvergedDefaultSetUIRNorm() and KSPConvergedDefaultSetUMIRNorm() together");
619: ctx->mininitialrtol = PETSC_TRUE;
620: return(0);
621: }
623: /*@C
624: KSPConvergedDefault - Determines convergence of the linear iterative solvers by default
626: Collective on ksp
628: Input Parameters:
629: + ksp - iterative context
630: . n - iteration number
631: . rnorm - residual norm (may be estimated, depending on the method may be the preconditioned residual norm)
632: - ctx - convergence context which must be created by KSPConvergedDefaultCreate()
634: Output Parameter:
635: + positive - if the iteration has converged;
636: . negative - if residual norm exceeds divergence threshold;
637: - 0 - otherwise.
639: Notes:
640: KSPConvergedDefault() reaches convergence when rnorm < MAX (rtol * rnorm_0, abstol);
641: Divergence is detected if rnorm > dtol * rnorm_0,
643: where:
644: + rtol = relative tolerance,
645: . abstol = absolute tolerance.
646: . dtol = divergence tolerance,
647: - rnorm_0 is the two norm of the right hand side (or the preconditioned norm, depending on what was set with
648: KSPSetNormType(). When initial guess is non-zero you
649: can call KSPConvergedDefaultSetUIRNorm() to use the norm of (b - A*(initial guess))
650: as the starting point for relative norm convergence testing, that is as rnorm_0
652: Use KSPSetTolerances() to alter the defaults for rtol, abstol, dtol.
654: Use KSPSetNormType() (or -ksp_norm_type <none,preconditioned,unpreconditioned,natural>) to change the norm used for computing rnorm
656: The precise values of reason are macros such as KSP_CONVERGED_RTOL, which are defined in petscksp.h.
658: This routine is used by KSP by default so the user generally never needs call it directly.
660: Use KSPSetConvergenceTest() to provide your own test instead of using this one.
662: Level: intermediate
664: .seealso: KSPSetConvergenceTest(), KSPSetTolerances(), KSPConvergedSkip(), KSPConvergedReason, KSPGetConvergedReason(),
665: KSPConvergedDefaultSetUIRNorm(), KSPConvergedDefaultSetUMIRNorm(), KSPConvergedDefaultCreate(), KSPConvergedDefaultDestroy()
666: @*/
667: PetscErrorCode KSPConvergedDefault(KSP ksp,PetscInt n,PetscReal rnorm,KSPConvergedReason *reason,void *ctx)
668: {
669: PetscErrorCode ierr;
670: KSPConvergedDefaultCtx *cctx = (KSPConvergedDefaultCtx*) ctx;
671: KSPNormType normtype;
676: *reason = KSP_CONVERGED_ITERATING;
678: KSPGetNormType(ksp,&normtype);
679: if (normtype == KSP_NORM_NONE) return(0);
681: if (!cctx) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_NULL,"Convergence context must have been created with KSPConvergedDefaultCreate()");
682: if (!n) {
683: /* if user gives initial guess need to compute norm of b */
684: if (!ksp->guess_zero && !cctx->initialrtol) {
685: PetscReal snorm = 0.0;
686: if (ksp->normtype == KSP_NORM_UNPRECONDITIONED || ksp->pc_side == PC_RIGHT) {
687: PetscInfo(ksp,"user has provided nonzero initial guess, computing 2-norm of RHS\n");
688: VecNorm(ksp->vec_rhs,NORM_2,&snorm); /* <- b'*b */
689: } else {
690: Vec z;
691: /* Should avoid allocating the z vector each time but cannot stash it in cctx because if KSPReset() is called the vector size might change */
692: VecDuplicate(ksp->vec_rhs,&z);
693: KSP_PCApply(ksp,ksp->vec_rhs,z);
694: if (ksp->normtype == KSP_NORM_PRECONDITIONED) {
695: PetscInfo(ksp,"user has provided nonzero initial guess, computing 2-norm of preconditioned RHS\n");
696: VecNorm(z,NORM_2,&snorm); /* dp <- b'*B'*B*b */
697: } else if (ksp->normtype == KSP_NORM_NATURAL) {
698: PetscScalar norm;
699: PetscInfo(ksp,"user has provided nonzero initial guess, computing natural norm of RHS\n");
700: VecDot(ksp->vec_rhs,z,&norm);
701: snorm = PetscSqrtReal(PetscAbsScalar(norm)); /* dp <- b'*B*b */
702: }
703: VecDestroy(&z);
704: }
705: /* handle special case of zero RHS and nonzero guess */
706: if (!snorm) {
707: PetscInfo(ksp,"Special case, user has provided nonzero initial guess and zero RHS\n");
708: snorm = rnorm;
709: }
710: if (cctx->mininitialrtol) ksp->rnorm0 = PetscMin(snorm,rnorm);
711: else ksp->rnorm0 = snorm;
712: } else {
713: ksp->rnorm0 = rnorm;
714: }
715: ksp->ttol = PetscMax(ksp->rtol*ksp->rnorm0,ksp->abstol);
716: }
718: if (n <= ksp->chknorm) return(0);
720: if (PetscIsInfOrNanReal(rnorm)) {
721: PCFailedReason pcreason;
722: PetscInt sendbuf,pcreason_max;
723: PCGetFailedReason(ksp->pc,&pcreason);
724: sendbuf = (PetscInt)pcreason;
725: MPI_Allreduce(&sendbuf,&pcreason_max,1,MPIU_INT,MPIU_MAX,PetscObjectComm((PetscObject)ksp));
726: if (pcreason_max) {
727: *reason = KSP_DIVERGED_PC_FAILED;
728: VecSetInf(ksp->vec_sol);
729: PetscInfo(ksp,"Linear solver pcsetup fails, declaring divergence \n");
730: } else {
731: *reason = KSP_DIVERGED_NANORINF;
732: PetscInfo(ksp,"Linear solver has created a not a number (NaN) as the residual norm, declaring divergence \n");
733: }
734: } else if (rnorm <= ksp->ttol) {
735: if (rnorm < ksp->abstol) {
736: PetscInfo3(ksp,"Linear solver has converged. Residual norm %14.12e is less than absolute tolerance %14.12e at iteration %D\n",(double)rnorm,(double)ksp->abstol,n);
737: *reason = KSP_CONVERGED_ATOL;
738: } else {
739: if (cctx->initialrtol) {
740: PetscInfo4(ksp,"Linear solver has converged. Residual norm %14.12e is less than relative tolerance %14.12e times initial residual norm %14.12e at iteration %D\n",(double)rnorm,(double)ksp->rtol,(double)ksp->rnorm0,n);
741: } else {
742: PetscInfo4(ksp,"Linear solver has converged. Residual norm %14.12e is less than relative tolerance %14.12e times initial right hand side norm %14.12e at iteration %D\n",(double)rnorm,(double)ksp->rtol,(double)ksp->rnorm0,n);
743: }
744: *reason = KSP_CONVERGED_RTOL;
745: }
746: } else if (rnorm >= ksp->divtol*ksp->rnorm0) {
747: PetscInfo3(ksp,"Linear solver is diverging. Initial right hand size norm %14.12e, current residual norm %14.12e at iteration %D\n",(double)ksp->rnorm0,(double)rnorm,n);
748: *reason = KSP_DIVERGED_DTOL;
749: }
750: return(0);
751: }
753: /*@C
754: KSPConvergedDefaultDestroy - Frees the space used by the KSPConvergedDefault() function context
756: Not Collective
758: Input Parameters:
759: . ctx - convergence context
761: Level: intermediate
763: .seealso: KSPConvergedDefault(), KSPConvergedDefaultCreate(), KSPSetConvergenceTest(), KSPSetTolerances(), KSPConvergedSkip(),
764: KSPConvergedReason, KSPGetConvergedReason(), KSPConvergedDefaultSetUIRNorm(), KSPConvergedDefaultSetUMIRNorm()
765: @*/
766: PetscErrorCode KSPConvergedDefaultDestroy(void *ctx)
767: {
768: PetscErrorCode ierr;
769: KSPConvergedDefaultCtx *cctx = (KSPConvergedDefaultCtx*) ctx;
772: VecDestroy(&cctx->work);
773: PetscFree(ctx);
774: return(0);
775: }
777: /*
778: KSPBuildSolutionDefault - Default code to create/move the solution.
780: Collective on ksp
782: Input Parameters:
783: + ksp - iterative context
784: - v - pointer to the user's vector
786: Output Parameter:
787: . V - pointer to a vector containing the solution
789: Level: advanced
791: Developers Note: This is PETSC_EXTERN because it may be used by user written plugin KSP implementations
793: .seealso: KSPGetSolution(), KSPBuildResidualDefault()
794: */
795: PetscErrorCode KSPBuildSolutionDefault(KSP ksp,Vec v,Vec *V)
796: {
800: if (ksp->pc_side == PC_RIGHT) {
801: if (ksp->pc) {
802: if (v) {
803: KSP_PCApply(ksp,ksp->vec_sol,v); *V = v;
804: } else SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"Not working with right preconditioner");
805: } else {
806: if (v) {
807: VecCopy(ksp->vec_sol,v); *V = v;
808: } else *V = ksp->vec_sol;
809: }
810: } else if (ksp->pc_side == PC_SYMMETRIC) {
811: if (ksp->pc) {
812: if (ksp->transpose_solve) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"Not working with symmetric preconditioner and transpose solve");
813: if (v) {
814: PCApplySymmetricRight(ksp->pc,ksp->vec_sol,v);
815: *V = v;
816: } else SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"Not working with symmetric preconditioner");
817: } else {
818: if (v) {
819: VecCopy(ksp->vec_sol,v); *V = v;
820: } else *V = ksp->vec_sol;
821: }
822: } else {
823: if (v) {
824: VecCopy(ksp->vec_sol,v); *V = v;
825: } else *V = ksp->vec_sol;
826: }
827: return(0);
828: }
830: /*
831: KSPBuildResidualDefault - Default code to compute the residual.
833: Collecive on ksp
835: Input Parameters:
836: . ksp - iterative context
837: . t - pointer to temporary vector
838: . v - pointer to user vector
840: Output Parameter:
841: . V - pointer to a vector containing the residual
843: Level: advanced
845: Developers Note: This is PETSC_EXTERN because it may be used by user written plugin KSP implementations
847: .seealso: KSPBuildSolutionDefault()
848: */
849: PetscErrorCode KSPBuildResidualDefault(KSP ksp,Vec t,Vec v,Vec *V)
850: {
852: Mat Amat,Pmat;
855: if (!ksp->pc) {KSPGetPC(ksp,&ksp->pc);}
856: PCGetOperators(ksp->pc,&Amat,&Pmat);
857: KSPBuildSolution(ksp,t,NULL);
858: KSP_MatMult(ksp,Amat,t,v);
859: VecAYPX(v,-1.0,ksp->vec_rhs);
860: *V = v;
861: return(0);
862: }
864: /*@C
865: KSPCreateVecs - Gets a number of work vectors.
867: Collective on ksp
869: Input Parameters:
870: + ksp - iterative context
871: . rightn - number of right work vectors
872: - leftn - number of left work vectors to allocate
874: Output Parameter:
875: + right - the array of vectors created
876: - left - the array of left vectors
878: Note: The right vector has as many elements as the matrix has columns. The left
879: vector has as many elements as the matrix has rows.
881: The vectors are new vectors that are not owned by the KSP, they should be destroyed with calls to VecDestroyVecs() when no longer needed.
883: Developers Note: First tries to duplicate the rhs and solution vectors of the KSP, if they do not exist tries to get them from the matrix, if
884: that does not exist tries to get them from the DM (if it is provided).
886: Level: advanced
888: .seealso: MatCreateVecs(), VecDestroyVecs()
890: @*/
891: PetscErrorCode KSPCreateVecs(KSP ksp,PetscInt rightn, Vec **right,PetscInt leftn,Vec **left)
892: {
894: Vec vecr = NULL,vecl = NULL;
895: PetscBool matset,pmatset;
896: Mat mat = NULL;
899: if (rightn) {
900: if (!right) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_INCOMP,"You asked for right vectors but did not pass a pointer to hold them");
901: if (ksp->vec_sol) vecr = ksp->vec_sol;
902: else {
903: if (ksp->pc) {
904: PCGetOperatorsSet(ksp->pc,&matset,&pmatset);
905: /* check for mat before pmat because for KSPLSQR pmat may be a different size than mat since pmat maybe mat'*mat */
906: if (matset) {
907: PCGetOperators(ksp->pc,&mat,NULL);
908: MatCreateVecs(mat,&vecr,NULL);
909: } else if (pmatset) {
910: PCGetOperators(ksp->pc,NULL,&mat);
911: MatCreateVecs(mat,&vecr,NULL);
912: }
913: }
914: if (!vecr) {
915: if (ksp->dm) {
916: DMGetGlobalVector(ksp->dm,&vecr);
917: } else SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_WRONGSTATE,"You requested a vector from a KSP that cannot provide one");
918: }
919: }
920: VecDuplicateVecs(vecr,rightn,right);
921: if (!ksp->vec_sol) {
922: if (mat) {
923: VecDestroy(&vecr);
924: } else if (ksp->dm) {
925: DMRestoreGlobalVector(ksp->dm,&vecr);
926: }
927: }
928: }
929: if (leftn) {
930: if (!left) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_INCOMP,"You asked for left vectors but did not pass a pointer to hold them");
931: if (ksp->vec_rhs) vecl = ksp->vec_rhs;
932: else {
933: if (ksp->pc) {
934: PCGetOperatorsSet(ksp->pc,&matset,&pmatset);
935: /* check for mat before pmat because for KSPLSQR pmat may be a different size than mat since pmat maybe mat'*mat */
936: if (matset) {
937: PCGetOperators(ksp->pc,&mat,NULL);
938: MatCreateVecs(mat,NULL,&vecl);
939: } else if (pmatset) {
940: PCGetOperators(ksp->pc,NULL,&mat);
941: MatCreateVecs(mat,NULL,&vecl);
942: }
943: }
944: if (!vecl) {
945: if (ksp->dm) {
946: DMGetGlobalVector(ksp->dm,&vecl);
947: } else SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_WRONGSTATE,"You requested a vector from a KSP that cannot provide one");
948: }
949: }
950: VecDuplicateVecs(vecl,leftn,left);
951: if (!ksp->vec_rhs) {
952: if (mat) {
953: VecDestroy(&vecl);
954: } else if (ksp->dm) {
955: DMRestoreGlobalVector(ksp->dm,&vecl);
956: }
957: }
958: }
959: return(0);
960: }
962: /*@C
963: KSPSetWorkVecs - Sets a number of work vectors into a KSP object
965: Collective on ksp
967: Input Parameters:
968: + ksp - iterative context
969: - nw - number of work vectors to allocate
971: Level: developer
973: Developers Note: This is PETSC_EXTERN because it may be used by user written plugin KSP implementations
975: @*/
976: PetscErrorCode KSPSetWorkVecs(KSP ksp,PetscInt nw)
977: {
981: VecDestroyVecs(ksp->nwork,&ksp->work);
982: ksp->nwork = nw;
983: KSPCreateVecs(ksp,nw,&ksp->work,0,NULL);
984: PetscLogObjectParents(ksp,nw,ksp->work);
985: return(0);
986: }
988: /*
989: KSPDestroyDefault - Destroys a iterative context variable for methods with
990: no separate context. Preferred calling sequence KSPDestroy().
992: Input Parameter:
993: . ksp - the iterative context
995: Developers Note: This is PETSC_EXTERN because it may be used by user written plugin KSP implementations
997: */
998: PetscErrorCode KSPDestroyDefault(KSP ksp)
999: {
1004: PetscFree(ksp->data);
1005: return(0);
1006: }
1008: /*@
1009: KSPGetConvergedReason - Gets the reason the KSP iteration was stopped.
1011: Not Collective
1013: Input Parameter:
1014: . ksp - the KSP context
1016: Output Parameter:
1017: . reason - negative value indicates diverged, positive value converged, see KSPConvergedReason
1019: Possible values for reason: See also manual page for each reason
1020: $ KSP_CONVERGED_RTOL (residual 2-norm decreased by a factor of rtol, from 2-norm of right hand side)
1021: $ KSP_CONVERGED_ATOL (residual 2-norm less than abstol)
1022: $ KSP_CONVERGED_ITS (used by the preonly preconditioner that always uses ONE iteration, or when the KSPConvergedSkip() convergence test routine is set.
1023: $ KSP_CONVERGED_CG_NEG_CURVE (see note below)
1024: $ KSP_CONVERGED_CG_CONSTRAINED (see note below)
1025: $ KSP_CONVERGED_STEP_LENGTH (see note below)
1026: $ KSP_CONVERGED_ITERATING (returned if the solver is not yet finished)
1027: $ KSP_DIVERGED_ITS (required more than its to reach convergence)
1028: $ KSP_DIVERGED_DTOL (residual norm increased by a factor of divtol)
1029: $ KSP_DIVERGED_NANORINF (residual norm became Not-a-number or Inf likely due to 0/0)
1030: $ KSP_DIVERGED_BREAKDOWN (generic breakdown in method)
1031: $ KSP_DIVERGED_BREAKDOWN_BICG (Initial residual is orthogonal to preconditioned initial residual. Try a different preconditioner, or a different initial Level.)
1033: Options Database:
1034: . -ksp_converged_reason - prints the reason to standard out
1036: Notes:
1037: If this routine is called before or doing the KSPSolve() the value of KSP_CONVERGED_ITERATING is returned
1039: The values KSP_CONVERGED_CG_NEG_CURVE, KSP_CONVERGED_CG_CONSTRAINED, and KSP_CONVERGED_STEP_LENGTH are returned only by the special KSPNASH, KSPSTCG, and KSPGLTR
1040: solvers which are used by the SNESNEWTONTR (trust region) solver.
1042: Level: intermediate
1044: .seealso: KSPSetConvergenceTest(), KSPConvergedDefault(), KSPSetTolerances(), KSPConvergedReason
1045: @*/
1046: PetscErrorCode KSPGetConvergedReason(KSP ksp,KSPConvergedReason *reason)
1047: {
1051: *reason = ksp->reason;
1052: return(0);
1053: }
1055: #include <petsc/private/dmimpl.h>
1056: /*@
1057: KSPSetDM - Sets the DM that may be used by some preconditioners
1059: Logically Collective on ksp
1061: Input Parameters:
1062: + ksp - the preconditioner context
1063: - dm - the dm, cannot be NULL
1065: Notes:
1066: If this is used then the KSP will attempt to use the DM to create the matrix and use the routine set with
1067: DMKSPSetComputeOperators(). Use KSPSetDMActive(ksp,PETSC_FALSE) to instead use the matrix you've provided with
1068: KSPSetOperators().
1070: A DM can only be used for solving one problem at a time because information about the problem is stored on the DM,
1071: even when not using interfaces like DMKSPSetComputeOperators(). Use DMClone() to get a distinct DM when solving
1072: different problems using the same function space.
1074: Level: intermediate
1076: .seealso: KSPGetDM(), KSPSetDMActive(), KSPSetComputeOperators(), KSPSetComputeRHS(), KSPSetComputeInitialGuess(), DMKSPSetComputeOperators(), DMKSPSetComputeRHS(), DMKSPSetComputeInitialGuess()
1077: @*/
1078: PetscErrorCode KSPSetDM(KSP ksp,DM dm)
1079: {
1081: PC pc;
1086: PetscObjectReference((PetscObject)dm);
1087: if (ksp->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
1088: if (ksp->dm->dmksp && !dm->dmksp) {
1089: DMKSP kdm;
1090: DMCopyDMKSP(ksp->dm,dm);
1091: DMGetDMKSP(ksp->dm,&kdm);
1092: if (kdm->originaldm == ksp->dm) kdm->originaldm = dm; /* Grant write privileges to the replacement DM */
1093: }
1094: DMDestroy(&ksp->dm);
1095: }
1096: ksp->dm = dm;
1097: ksp->dmAuto = PETSC_FALSE;
1098: KSPGetPC(ksp,&pc);
1099: PCSetDM(pc,dm);
1100: ksp->dmActive = PETSC_TRUE;
1101: return(0);
1102: }
1104: /*@
1105: KSPSetDMActive - Indicates the DM should be used to generate the linear system matrix and right hand side
1107: Logically Collective on ksp
1109: Input Parameters:
1110: + ksp - the preconditioner context
1111: - flg - use the DM
1113: Notes:
1114: By default KSPSetDM() sets the DM as active, call KSPSetDMActive(ksp,PETSC_FALSE); after KSPSetDM(ksp,dm) to not have the KSP object use the DM to generate the matrices.
1116: Level: intermediate
1118: .seealso: KSPGetDM(), KSPSetDM(), SNESSetDM(), KSPSetComputeOperators(), KSPSetComputeRHS(), KSPSetComputeInitialGuess()
1119: @*/
1120: PetscErrorCode KSPSetDMActive(KSP ksp,PetscBool flg)
1121: {
1125: ksp->dmActive = flg;
1126: return(0);
1127: }
1129: /*@
1130: KSPGetDM - Gets the DM that may be used by some preconditioners
1132: Not Collective
1134: Input Parameter:
1135: . ksp - the preconditioner context
1137: Output Parameter:
1138: . dm - the dm
1140: Level: intermediate
1143: .seealso: KSPSetDM(), KSPSetDMActive()
1144: @*/
1145: PetscErrorCode KSPGetDM(KSP ksp,DM *dm)
1146: {
1151: if (!ksp->dm) {
1152: DMShellCreate(PetscObjectComm((PetscObject)ksp),&ksp->dm);
1153: ksp->dmAuto = PETSC_TRUE;
1154: }
1155: *dm = ksp->dm;
1156: return(0);
1157: }
1159: /*@
1160: KSPSetApplicationContext - Sets the optional user-defined context for the linear solver.
1162: Logically Collective on ksp
1164: Input Parameters:
1165: + ksp - the KSP context
1166: - usrP - optional user context
1168: Fortran Notes:
1169: To use this from Fortran you must write a Fortran interface definition for this
1170: function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.
1172: Level: intermediate
1174: .seealso: KSPGetApplicationContext()
1175: @*/
1176: PetscErrorCode KSPSetApplicationContext(KSP ksp,void *usrP)
1177: {
1179: PC pc;
1183: ksp->user = usrP;
1184: KSPGetPC(ksp,&pc);
1185: PCSetApplicationContext(pc,usrP);
1186: return(0);
1187: }
1189: /*@
1190: KSPGetApplicationContext - Gets the user-defined context for the linear solver.
1192: Not Collective
1194: Input Parameter:
1195: . ksp - KSP context
1197: Output Parameter:
1198: . usrP - user context
1200: Fortran Notes:
1201: To use this from Fortran you must write a Fortran interface definition for this
1202: function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.
1204: Level: intermediate
1206: .seealso: KSPSetApplicationContext()
1207: @*/
1208: PetscErrorCode KSPGetApplicationContext(KSP ksp,void *usrP)
1209: {
1212: *(void**)usrP = ksp->user;
1213: return(0);
1214: }
1216: #include <petsc/private/pcimpl.h>
1218: /*@
1219: KSPCheckSolve - Checks if the PCSetUp() or KSPSolve() failed and set the error flag for the outer PC. A KSP_DIVERGED_ITS is
1220: not considered a failure in this context
1222: Collective on ksp
1224: Input Parameter:
1225: + ksp - the linear solver (KSP) context.
1226: . pc - the preconditioner context
1227: - vec - a vector that will be initialized with Inf to indicate lack of convergence
1229: Notes: this may be called by a subset of the processes in the PC
1231: Level: developer
1233: Developer Note: this is used to manage returning from preconditioners whose inner KSP solvers have failed in some way
1235: .seealso: KSPCreate(), KSPSetType(), KSP, KSPCheckNorm(), KSPCheckDot()
1236: @*/
1237: PetscErrorCode KSPCheckSolve(KSP ksp,PC pc,Vec vec)
1238: {
1239: PetscErrorCode ierr;
1240: PCFailedReason pcreason;
1241: PC subpc;
1244: KSPGetPC(ksp,&subpc);
1245: PCGetFailedReason(subpc,&pcreason);
1246: if (pcreason || (ksp->reason < 0 && ksp->reason != KSP_DIVERGED_ITS)) {
1247: if (pc->erroriffailure) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_NOT_CONVERGED,"Detected not converged in KSP inner solve: KSP reason %s PC reason %s",KSPConvergedReasons[ksp->reason],PCFailedReasons[pcreason]);
1248: else {
1249: PetscInfo2(ksp,"Detected not converged in KSP inner solve: KSP reason %s PC reason %s\n",KSPConvergedReasons[ksp->reason],PCFailedReasons[pcreason]);
1250: pc->failedreason = PC_SUBPC_ERROR;
1251: VecSetInf(vec);
1252: }
1253: }
1254: return(0);
1255: }
1256: