Actual source code: itcreate.c

  1: #define PETSCKSP_DLL

  3: /*
  4:      The basic KSP routines, Create, View etc. are here.
  5: */
 6:  #include include/private/kspimpl.h
 7:  #include petscsys.h

  9: /* Logging support */
 10: PetscCookie  KSP_COOKIE = 0;
 11: PetscEvent  KSP_GMRESOrthogonalization = 0, KSP_SetUp = 0, KSP_Solve = 0;


 14: PetscTruth KSPRegisterAllCalled = PETSC_FALSE;

 18: /*@C 
 19:    KSPView - Prints the KSP data structure.

 21:    Collective on KSP

 23:    Input Parameters:
 24: +  ksp - the Krylov space context
 25: -  viewer - visualization context

 27:    Options Database Keys:
 28: .  -ksp_view - print the ksp data structure at the end of a KSPSolve call

 30:    Note:
 31:    The available visualization contexts include
 32: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
 33: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
 34:          output where only the first processor opens
 35:          the file.  All other processors send their 
 36:          data to the first processor to print. 

 38:    The user can open an alternative visualization context with
 39:    PetscViewerASCIIOpen() - output to a specified file.

 41:    Level: beginner

 43: .keywords: KSP, view

 45: .seealso: PCView(), PetscViewerASCIIOpen()
 46: @*/
 47: PetscErrorCode  KSPView(KSP ksp,PetscViewer viewer)
 48: {
 49:   const char     *type;
 51:   PetscTruth     iascii;

 55:   if (!viewer) viewer = PETSC_VIEWER_STDOUT_(ksp->comm);

 59:   PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);
 60:   if (iascii) {
 61:     KSPGetType(ksp,&type);
 62:     if (ksp->prefix) {
 63:       PetscViewerASCIIPrintf(viewer,"KSP Object:(%s)\n",ksp->prefix);
 64:     } else {
 65:       PetscViewerASCIIPrintf(viewer,"KSP Object:\n");
 66:     }
 67:     if (type) {
 68:       PetscViewerASCIIPrintf(viewer,"  type: %s\n",type);
 69:     } else {
 70:       PetscViewerASCIIPrintf(viewer,"  type: not yet set\n");
 71:     }
 72:     if (ksp->ops->view) {
 73:       PetscViewerASCIIPushTab(viewer);
 74:       (*ksp->ops->view)(ksp,viewer);
 75:       PetscViewerASCIIPopTab(viewer);
 76:     }
 77:     if (ksp->guess_zero) {PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, initial guess is zero\n",ksp->max_it);}
 78:     else                 {PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D\n", ksp->max_it);}
 79:     if (ksp->guess_knoll) {PetscViewerASCIIPrintf(viewer,"  using preconditioner applied to right hand side for initial guess\n");}
 80:     PetscViewerASCIIPrintf(viewer,"  tolerances:  relative=%G, absolute=%G, divergence=%G\n",ksp->rtol,ksp->abstol,ksp->divtol);
 81:     if (ksp->pc_side == PC_RIGHT)          {PetscViewerASCIIPrintf(viewer,"  right preconditioning\n");}
 82:     else if (ksp->pc_side == PC_SYMMETRIC) {PetscViewerASCIIPrintf(viewer,"  symmetric preconditioning\n");}
 83:     else                                   {PetscViewerASCIIPrintf(viewer,"  left preconditioning\n");}
 84:   } else {
 85:     if (ksp->ops->view) {
 86:       (*ksp->ops->view)(ksp,viewer);
 87:     }
 88:   }
 89:   PCView(ksp->pc,viewer);
 90:   return(0);
 91: }

 93: /*
 94:    Contains the list of registered KSP routines
 95: */
 96: PetscFList KSPList = 0;

100: /*@
101:    KSPSetNormType - Sets the norm that is used for convergence testing.

103:    Collective on KSP

105:    Input Parameter:
106: +  ksp - Krylov solver context
107: -  normtype - one of 
108: $   KSP_NORM_NO - skips computing the norm, this should only be used if you are using
109: $                 the Krylov method as a smoother with a fixed small number of iterations.
110: $                 You must also call KSPSetConvergenceTest(ksp,KSPSkipConverged,PETSC_NULL);
111: $                 supported only by CG, Richardson, Bi-CG-stab, CR, and CGS methods.
112: $   KSP_NORM_PRECONDITIONED - the default for left preconditioned solves, uses the l2 norm
113: $                 of the preconditioned residual
114: $   KSP_NORM_UNPRECONDITIONED - uses the l2 norm of the true b - Ax residual, supported only by
115: $                 CG, CHEBYCHEV, and RICHARDSON, automatically true for right (see KSPSetPreconditioningSide()) 
116: $                 preconditioning..
117: $   KSP_NORM_NATURAL - supported  by cg, cr, and cgs 


120:    Options Database Key:
121: .   -ksp_norm_type <none,preconditioned,unpreconditioned,natural>

123:    Notes: 
124:    Currently only works with the CG, Richardson, Bi-CG-stab, CR, and CGS methods.

126:    Level: advanced

128: .keywords: KSP, create, context, norms

130: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSPSkipConverged()                               
131: @*/
132: PetscErrorCode  KSPSetNormType(KSP ksp,KSPNormType normtype)
133: {

138:   ksp->normtype = normtype;
139:   if (normtype == KSP_NORM_NO) {
140:     PetscInfo(ksp,"Warning seting KSPNormType to skip computing the norm\n\
141:   make sure you set the KSP convergence test to KSPSkipConvergence\n");
142:   }
143:   return(0);
144: }

148: /*@
149:    KSPGetNormType - Sets the norm that is used for convergence testing.

151:    Not Collective

153:    Input Parameter:
154: .  ksp - Krylov solver context

156:    Output Parameter:
157: .  normtype - norm that is used for convergence testing

159:    Level: advanced

161: .keywords: KSP, create, context, norms

163: .seealso: KSPNormType, KSPSetNormType(), KSPSkipConverged()
164: @*/
165: PetscErrorCode  KSPGetNormType(KSP ksp, KSPNormType *normtype) {
169:   *normtype = ksp->normtype;
170:   return(0);
171: }

175: static PetscErrorCode KSPPublish_Petsc(PetscObject obj)
176: {
178:   return(0);
179: }

183: /*@
184:    KSPSetOperators - Sets the matrix associated with the linear system
185:    and a (possibly) different one associated with the preconditioner. 

187:    Collective on KSP and Mat

189:    Input Parameters:
190: +  ksp - the KSP context
191: .  Amat - the matrix associated with the linear system
192: .  Pmat - the matrix to be used in constructing the preconditioner, usually the
193:           same as Amat. 
194: -  flag - flag indicating information about the preconditioner matrix structure
195:    during successive linear solves.  This flag is ignored the first time a
196:    linear system is solved, and thus is irrelevant when solving just one linear
197:    system.

199:    Notes: 
200:    The flag can be used to eliminate unnecessary work in the preconditioner 
201:    during the repeated solution of linear systems of the same size.  The
202:    available options are
203: $    SAME_PRECONDITIONER -
204: $      Pmat is identical during successive linear solves.
205: $      This option is intended for folks who are using
206: $      different Amat and Pmat matrices and want to reuse the
207: $      same preconditioner matrix.  For example, this option
208: $      saves work by not recomputing incomplete factorization
209: $      for ILU/ICC preconditioners.
210: $    SAME_NONZERO_PATTERN -
211: $      Pmat has the same nonzero structure during
212: $      successive linear solves. 
213: $    DIFFERENT_NONZERO_PATTERN -
214: $      Pmat does not have the same nonzero structure.

216:     Caution:
217:     If you specify SAME_NONZERO_PATTERN, PETSc believes your assertion
218:     and does not check the structure of the matrix.  If you erroneously
219:     claim that the structure is the same when it actually is not, the new
220:     preconditioner will not function correctly.  Thus, use this optimization
221:     feature carefully!

223:     If in doubt about whether your preconditioner matrix has changed
224:     structure or not, use the flag DIFFERENT_NONZERO_PATTERN.

226:     Level: beginner

228:    Alternative usage: If the operators have NOT been set with KSP/PCSetOperators() then the operators
229:       are created in PC and returned to the user. In this case, if both operators
230:       mat and pmat are requested, two DIFFERENT operators will be returned. If
231:       only one is requested both operators in the PC will be the same (i.e. as
232:       if one had called KSP/PCSetOperators() with the same argument for both Mats).
233:       The user must set the sizes of the returned matrices and their type etc just
234:       as if the user created them with MatCreate(). For example,

236: $         KSP/PCGetOperators(ksp/pc,&mat,PETSC_NULL,PETSC_NULL); is equivalent to
237: $           set size, type, etc of mat

239: $         MatCreate(comm,&mat);
240: $         KSP/PCSetOperators(ksp/pc,mat,mat,SAME_NONZERO_PATTERN);
241: $         PetscObjectDereference((PetscObject)mat);
242: $           set size, type, etc of mat

244:      and

246: $         KSP/PCGetOperators(ksp/pc,&mat,&pmat,PETSC_NULL); is equivalent to
247: $           set size, type, etc of mat and pmat

249: $         MatCreate(comm,&mat);
250: $         MatCreate(comm,&pmat);
251: $         KSP/PCSetOperators(ksp/pc,mat,pmat,SAME_NONZERO_PATTERN);
252: $         PetscObjectDereference((PetscObject)mat);
253: $         PetscObjectDereference((PetscObject)pmat);
254: $           set size, type, etc of mat and pmat

256:     The rational for this support is so that when creating a TS, SNES, or KSP the hierarchy
257:     of underlying objects (i.e. SNES, KSP, PC, Mat) and their livespans can be completely 
258:     managed by the top most level object (i.e. the TS, SNES, or KSP). Another way to look
259:     at this is when you create a SNES you do not NEED to create a KSP and attach it to 
260:     the SNES object (the SNES object manages it for you). Similarly when you create a KSP
261:     you do not need to attach a PC to it (the KSP object manages the PC object for you).
262:     Thus, why should YOU have to create the Mat and attach it to the SNES/KSP/PC, when
263:     it can be created for you?

265: .keywords: KSP, set, operators, matrix, preconditioner, linear system

267: .seealso: KSPSolve(), KSPGetPC(), PCGetOperators(), PCSetOperators(), KSPGetOperators()
268: @*/
269: PetscErrorCode  KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat,MatStructure flag)
270: {

279:   PCSetOperators(ksp->pc,Amat,Pmat,flag);
280:   if (ksp->setupcalled > 1) ksp->setupcalled = 1;  /* so that next solve call will call setup */
281:   return(0);
282: }

286: /*@
287:    KSPGetOperators - Gets the matrix associated with the linear system
288:    and a (possibly) different one associated with the preconditioner. 

290:    Collective on KSP and Mat

292:    Input Parameter:
293: .  ksp - the KSP context

295:    Output Parameters:
296: +  Amat - the matrix associated with the linear system
297: .  Pmat - the matrix to be used in constructing the preconditioner, usually the
298:           same as Amat. 
299: -  flag - flag indicating information about the preconditioner matrix structure
300:    during successive linear solves.  This flag is ignored the first time a
301:    linear system is solved, and thus is irrelevant when solving just one linear
302:    system.

304:     Level: intermediate

306: .keywords: KSP, set, get, operators, matrix, preconditioner, linear system

308: .seealso: KSPSolve(), KSPGetPC(), PCGetOperators(), PCSetOperators(), KSPSetOperators(), KSPGetOperatorsSet()
309: @*/
310: PetscErrorCode  KSPGetOperators(KSP ksp,Mat *Amat,Mat *Pmat,MatStructure *flag)
311: {

316:   PCGetOperators(ksp->pc,Amat,Pmat,flag);
317:   return(0);
318: }

322: /*@C
323:    KSPGetOperatorsSet - Determines if the matrix associated with the linear system and
324:    possibly a different one associated with the preconditioner have been set in the KSP.

326:    Not collective, though the results on all processes should be the same

328:    Input Parameter:
329: .  pc - the preconditioner context

331:    Output Parameters:
332: +  mat - the matrix associated with the linear system was set
333: -  pmat - matrix associated with the preconditioner was set, usually the same

335:    Level: intermediate

337: .keywords: KSP, get, operators, matrix, linear system

339: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperators(), PCGetOperatorsSet()
340: @*/
341: PetscErrorCode  KSPGetOperatorsSet(KSP ksp,PetscTruth *mat,PetscTruth *pmat)
342: {

347:   PCGetOperatorsSet(ksp->pc,mat,pmat);
348:   return(0);
349: }

353: /*@
354:    KSPCreate - Creates the default KSP context.

356:    Collective on MPI_Comm

358:    Input Parameter:
359: .  comm - MPI communicator

361:    Output Parameter:
362: .  ksp - location to put the KSP context

364:    Notes:
365:    The default KSP type is GMRES with a restart of 30, using modified Gram-Schmidt
366:    orthogonalization.

368:    Level: beginner

370: .keywords: KSP, create, context

372: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSP
373: @*/
374: PetscErrorCode  KSPCreate(MPI_Comm comm,KSP *inksp)
375: {
376:   KSP            ksp;

381:   *inksp = 0;
382: #ifndef PETSC_USE_DYNAMIC_LIBRARIES
383:   KSPInitializePackage(PETSC_NULL);
384: #endif

386:   PetscHeaderCreate(ksp,_p_KSP,struct _KSPOps,KSP_COOKIE,-1,"KSP",comm,KSPDestroy,KSPView);
387:   ksp->bops->publish = KSPPublish_Petsc;

389:   ksp->type          = -1;
390:   ksp->max_it        = 10000;
391:   ksp->pc_side       = PC_LEFT;
392:   ksp->rtol          = 1.e-5;
393:   ksp->abstol        = 1.e-50;
394:   ksp->divtol        = 1.e4;

396:   ksp->normtype            = KSP_NORM_PRECONDITIONED;
397:   ksp->rnorm               = 0.0;
398:   ksp->its                 = 0;
399:   ksp->guess_zero          = PETSC_TRUE;
400:   ksp->calc_sings          = PETSC_FALSE;
401:   ksp->res_hist            = PETSC_NULL;
402:   ksp->res_hist_alloc      = PETSC_NULL;
403:   ksp->res_hist_len        = 0;
404:   ksp->res_hist_max        = 0;
405:   ksp->res_hist_reset      = PETSC_TRUE;
406:   ksp->numbermonitors      = 0;

408:   ksp->converged           = KSPDefaultConverged;
409:   ksp->ops->buildsolution  = KSPDefaultBuildSolution;
410:   ksp->ops->buildresidual  = KSPDefaultBuildResidual;

412:   ksp->vec_sol         = 0;
413:   ksp->vec_rhs         = 0;
414:   ksp->pc              = 0;
415:   ksp->data            = 0;
416:   ksp->nwork           = 0;
417:   ksp->work            = 0;
418:   ksp->cnvP            = 0;
419:   ksp->reason          = KSP_CONVERGED_ITERATING;
420:   ksp->setupcalled     = 0;

422:   PetscPublishAll(ksp);
423:   PCCreate(comm,&ksp->pc);
424:   *inksp = ksp;
425:   return(0);
426: }
427: 
430: /*@C
431:    KSPSetType - Builds KSP for a particular solver. 

433:    Collective on KSP

435:    Input Parameters:
436: +  ksp      - the Krylov space context
437: -  type - a known method

439:    Options Database Key:
440: .  -ksp_type  <method> - Sets the method; use -help for a list 
441:     of available methods (for instance, cg or gmres)

443:    Notes:  
444:    See "petsc/include/petscksp.h" for available methods (for instance,
445:    KSPCG or KSPGMRES).

447:   Normally, it is best to use the KSPSetFromOptions() command and
448:   then set the KSP type from the options database rather than by using
449:   this routine.  Using the options database provides the user with
450:   maximum flexibility in evaluating the many different Krylov methods.
451:   The KSPSetType() routine is provided for those situations where it
452:   is necessary to set the iterative solver independently of the command
453:   line or options database.  This might be the case, for example, when
454:   the choice of iterative solver changes during the execution of the
455:   program, and the user's application is taking responsibility for
456:   choosing the appropriate method.  In other words, this routine is
457:   not for beginners.

459:   Level: intermediate

461: .keywords: KSP, set, method

463: .seealso: PCSetType(), KSPType

465: @*/
466: PetscErrorCode  KSPSetType(KSP ksp, KSPType type)
467: {
468:   PetscErrorCode ierr,(*r)(KSP);
469:   PetscTruth     match;


475:   PetscTypeCompare((PetscObject)ksp,type,&match);
476:   if (match) return(0);

478:    PetscFListFind(KSPList,ksp->comm,type,(void (**)(void)) &r);
479:   if (!r) SETERRQ1(PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested KSP type %s",type);
480:   /* Destroy the previous private KSP context */
481:   if (ksp->ops->destroy) { (*ksp->ops->destroy)(ksp); }
482:   /* Reinitialize function pointers in KSPOps structure */
483:   PetscMemzero(ksp->ops,sizeof(struct _KSPOps));
484:   ksp->ops->buildsolution = KSPDefaultBuildSolution;
485:   ksp->ops->buildresidual = KSPDefaultBuildResidual;
486:   /* Call the KSPCreate_XXX routine for this particular Krylov solver */
487:   ksp->setupcalled = 0;
488:   (*r)(ksp);
489:   PetscObjectChangeTypeName((PetscObject)ksp,type);
490:   return(0);
491: }

495: /*@
496:    KSPRegisterDestroy - Frees the list of KSP methods that were
497:    registered by KSPRegisterDynamic().

499:    Not Collective

501:    Level: advanced

503: .keywords: KSP, register, destroy

505: .seealso: KSPRegisterDynamic(), KSPRegisterAll()
506: @*/
507: PetscErrorCode  KSPRegisterDestroy(void)
508: {

512:   PetscFListDestroy(&KSPList);
513:   KSPRegisterAllCalled = PETSC_FALSE;
514:   return(0);
515: }

519: /*@C
520:    KSPGetType - Gets the KSP type as a string from the KSP object.

522:    Not Collective

524:    Input Parameter:
525: .  ksp - Krylov context 

527:    Output Parameter:
528: .  name - name of KSP method 

530:    Level: intermediate

532: .keywords: KSP, get, method, name

534: .seealso: KSPSetType()
535: @*/
536: PetscErrorCode  KSPGetType(KSP ksp,KSPType *type)
537: {
541:   *type = ksp->type_name;
542:   return(0);
543: }

547: /*@C
548:   KSPRegister - See KSPRegisterDynamic()

550:   Level: advanced
551: @*/
552: PetscErrorCode  KSPRegister(const char sname[],const char path[],const char name[],PetscErrorCode (*function)(KSP))
553: {
555:   char           fullname[PETSC_MAX_PATH_LEN];

558:   PetscFListConcat(path,name,fullname);
559:   PetscFListAdd(&KSPList,sname,fullname,(void (*)(void))function);
560:   return(0);
561: }

565: /*@
566:   KSPSetNullSpace - Sets the null space of the operator

568:   Collective on KSP

570:   Input Parameters:
571: +  ksp - the Krylov space object
572: -  nullsp - the null space of the operator

574:   Level: advanced

576: .seealso: KSPSetOperators(), MatNullSpaceCreate(), KSPGetNullSpace()
577: @*/
578: PetscErrorCode  KSPSetNullSpace(KSP ksp,MatNullSpace nullsp)
579: {

585:   PetscObjectReference((PetscObject)nullsp);
586:   if (ksp->nullsp) { MatNullSpaceDestroy(ksp->nullsp); }
587:   ksp->nullsp = nullsp;
588:   return(0);
589: }

593: /*@
594:   KSPGetNullSpace - Gets the null space of the operator

596:   Collective on KSP

598:   Input Parameters:
599: +  ksp - the Krylov space object
600: -  nullsp - the null space of the operator

602:   Level: advanced

604: .seealso: KSPSetOperators(), MatNullSpaceCreate(), KSPSetNullSpace()
605: @*/
606: PetscErrorCode  KSPGetNullSpace(KSP ksp,MatNullSpace *nullsp)
607: {
611:   *nullsp = ksp->nullsp;
612:   return(0);
613: }