Actual source code: nepbasic.c

slepc-3.8.2 2017-12-01
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2017, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.
  7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
  8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  9: */
 10: /*
 11:    Basic NEP routines
 12: */

 14: #include <slepc/private/nepimpl.h>      /*I "slepcnep.h" I*/

 16: PetscFunctionList NEPList = 0;
 17: PetscBool         NEPRegisterAllCalled = PETSC_FALSE;
 18: PetscClassId      NEP_CLASSID = 0;
 19: PetscLogEvent     NEP_SetUp = 0,NEP_Solve = 0,NEP_Refine = 0,NEP_FunctionEval = 0,NEP_JacobianEval = 0,NEP_DerivativesEval = 0;

 21: /*@
 22:    NEPCreate - Creates the default NEP context.

 24:    Collective on MPI_Comm

 26:    Input Parameter:
 27: .  comm - MPI communicator

 29:    Output Parameter:
 30: .  nep - location to put the NEP context

 32:    Level: beginner

 34: .seealso: NEPSetUp(), NEPSolve(), NEPDestroy(), NEP
 35: @*/
 36: PetscErrorCode NEPCreate(MPI_Comm comm,NEP *outnep)
 37: {
 39:   NEP            nep;

 43:   *outnep = 0;
 44:   NEPInitializePackage();
 45:   SlepcHeaderCreate(nep,NEP_CLASSID,"NEP","Nonlinear Eigenvalue Problem","NEP",comm,NEPDestroy,NEPView);

 47:   nep->max_it          = 0;
 48:   nep->nev             = 1;
 49:   nep->ncv             = 0;
 50:   nep->mpd             = 0;
 51:   nep->nini            = 0;
 52:   nep->target          = 0.0;
 53:   nep->tol             = PETSC_DEFAULT;
 54:   nep->conv            = NEP_CONV_REL;
 55:   nep->stop            = NEP_STOP_BASIC;
 56:   nep->which           = (NEPWhich)0;
 57:   nep->problem_type    = (NEPProblemType)0;
 58:   nep->refine          = NEP_REFINE_NONE;
 59:   nep->npart           = 1;
 60:   nep->rtol            = PETSC_DEFAULT;
 61:   nep->rits            = PETSC_DEFAULT;
 62:   nep->scheme          = (NEPRefineScheme)0;
 63:   nep->trackall        = PETSC_FALSE;

 65:   nep->computefunction = NULL;
 66:   nep->computejacobian = NULL;
 67:   nep->functionctx     = NULL;
 68:   nep->jacobianctx     = NULL;
 69:   nep->computederivatives = NULL;
 70:   nep->derivativesctx  = NULL;
 71:   nep->converged       = NEPConvergedRelative;
 72:   nep->convergeduser   = NULL;
 73:   nep->convergeddestroy= NULL;
 74:   nep->stopping        = NEPStoppingBasic;
 75:   nep->stoppinguser    = NULL;
 76:   nep->stoppingdestroy = NULL;
 77:   nep->convergedctx    = NULL;
 78:   nep->stoppingctx     = NULL;
 79:   nep->numbermonitors  = 0;

 81:   nep->ds              = NULL;
 82:   nep->V               = NULL;
 83:   nep->rg              = NULL;
 84:   nep->function        = NULL;
 85:   nep->function_pre    = NULL;
 86:   nep->jacobian        = NULL;
 87:   nep->derivatives     = NULL;
 88:   nep->A               = NULL;
 89:   nep->f               = NULL;
 90:   nep->nt              = 0;
 91:   nep->mstr            = DIFFERENT_NONZERO_PATTERN;
 92:   nep->IS              = NULL;
 93:   nep->eigr            = NULL;
 94:   nep->eigi            = NULL;
 95:   nep->errest          = NULL;
 96:   nep->perm            = NULL;
 97:   nep->nwork           = 0;
 98:   nep->work            = NULL;
 99:   nep->data            = NULL;

101:   nep->state           = NEP_STATE_INITIAL;
102:   nep->nconv           = 0;
103:   nep->its             = 0;
104:   nep->n               = 0;
105:   nep->nloc            = 0;
106:   nep->nrma            = NULL;
107:   nep->fui             = (NEPUserInterface)0;
108:   nep->reason          = NEP_CONVERGED_ITERATING;

110:   PetscNewLog(nep,&nep->sc);
111:   *outnep = nep;
112:   return(0);
113: }

115: /*@C
116:    NEPSetType - Selects the particular solver to be used in the NEP object.

118:    Logically Collective on NEP

120:    Input Parameters:
121: +  nep      - the nonlinear eigensolver context
122: -  type     - a known method

124:    Options Database Key:
125: .  -nep_type <method> - Sets the method; use -help for a list
126:     of available methods

128:    Notes:
129:    See "slepc/include/slepcnep.h" for available methods.

131:    Normally, it is best to use the NEPSetFromOptions() command and
132:    then set the NEP type from the options database rather than by using
133:    this routine.  Using the options database provides the user with
134:    maximum flexibility in evaluating the different available methods.
135:    The NEPSetType() routine is provided for those situations where it
136:    is necessary to set the iterative solver independently of the command
137:    line or options database.

139:    Level: intermediate

141: .seealso: NEPType
142: @*/
143: PetscErrorCode NEPSetType(NEP nep,NEPType type)
144: {
145:   PetscErrorCode ierr,(*r)(NEP);
146:   PetscBool      match;


152:   PetscObjectTypeCompare((PetscObject)nep,type,&match);
153:   if (match) return(0);

155:   PetscFunctionListFind(NEPList,type,&r);
156:   if (!r) SETERRQ1(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown NEP type given: %s",type);

158:   if (nep->ops->destroy) { (*nep->ops->destroy)(nep); }
159:   PetscMemzero(nep->ops,sizeof(struct _NEPOps));

161:   nep->state = NEP_STATE_INITIAL;
162:   PetscObjectChangeTypeName((PetscObject)nep,type);
163:   (*r)(nep);
164:   return(0);
165: }

167: /*@C
168:    NEPGetType - Gets the NEP type as a string from the NEP object.

170:    Not Collective

172:    Input Parameter:
173: .  nep - the eigensolver context

175:    Output Parameter:
176: .  name - name of NEP method

178:    Level: intermediate

180: .seealso: NEPSetType()
181: @*/
182: PetscErrorCode NEPGetType(NEP nep,NEPType *type)
183: {
187:   *type = ((PetscObject)nep)->type_name;
188:   return(0);
189: }

191: /*@C
192:    NEPRegister - Adds a method to the nonlinear eigenproblem solver package.

194:    Not Collective

196:    Input Parameters:
197: +  name - name of a new user-defined solver
198: -  function - routine to create the solver context

200:    Notes:
201:    NEPRegister() may be called multiple times to add several user-defined solvers.

203:    Sample usage:
204: .vb
205:     NEPRegister("my_solver",MySolverCreate);
206: .ve

208:    Then, your solver can be chosen with the procedural interface via
209: $     NEPSetType(nep,"my_solver")
210:    or at runtime via the option
211: $     -nep_type my_solver

213:    Level: advanced

215: .seealso: NEPRegisterAll()
216: @*/
217: PetscErrorCode NEPRegister(const char *name,PetscErrorCode (*function)(NEP))
218: {

222:   PetscFunctionListAdd(&NEPList,name,function);
223:   return(0);
224: }

226: /*
227:    NEPReset_Problem - Destroys the problem matrices.
228: @*/
229: PetscErrorCode NEPReset_Problem(NEP nep)
230: {
232:   PetscInt       i;

236:   MatDestroy(&nep->function);
237:   MatDestroy(&nep->function_pre);
238:   MatDestroy(&nep->jacobian);
239:   MatDestroy(&nep->derivatives);
240:   if (nep->fui==NEP_USER_INTERFACE_SPLIT) {
241:     MatDestroyMatrices(nep->nt,&nep->A);
242:     for (i=0;i<nep->nt;i++) {
243:       FNDestroy(&nep->f[i]);
244:     }
245:     PetscFree(nep->f);
246:     PetscFree(nep->nrma);
247:     nep->nt = 0;
248:   }
249:   return(0);
250: }
251: /*@
252:    NEPReset - Resets the NEP context to the initial state (prior to setup)
253:    and destroys any allocated Vecs and Mats.

255:    Collective on NEP

257:    Input Parameter:
258: .  nep - eigensolver context obtained from NEPCreate()

260:    Level: advanced

262: .seealso: NEPDestroy()
263: @*/
264: PetscErrorCode NEPReset(NEP nep)
265: {

270:   if (!nep) return(0);
271:   if (nep->ops->reset) { (nep->ops->reset)(nep); }
272:   if (nep->refineksp) { KSPReset(nep->refineksp); }
273:   NEPReset_Problem(nep);
274:   BVDestroy(&nep->V);
275:   VecDestroyVecs(nep->nwork,&nep->work);
276:   nep->nwork = 0;
277:   nep->state = NEP_STATE_INITIAL;
278:   return(0);
279: }

281: /*@
282:    NEPDestroy - Destroys the NEP context.

284:    Collective on NEP

286:    Input Parameter:
287: .  nep - eigensolver context obtained from NEPCreate()

289:    Level: beginner

291: .seealso: NEPCreate(), NEPSetUp(), NEPSolve()
292: @*/
293: PetscErrorCode NEPDestroy(NEP *nep)
294: {

298:   if (!*nep) return(0);
300:   if (--((PetscObject)(*nep))->refct > 0) { *nep = 0; return(0); }
301:   NEPReset(*nep);
302:   if ((*nep)->ops->destroy) { (*(*nep)->ops->destroy)(*nep); }
303:   if ((*nep)->eigr) {
304:     PetscFree4((*nep)->eigr,(*nep)->eigi,(*nep)->errest,(*nep)->perm);
305:   }
306:   RGDestroy(&(*nep)->rg);
307:   DSDestroy(&(*nep)->ds);
308:   KSPDestroy(&(*nep)->refineksp);
309:   PetscSubcommDestroy(&(*nep)->refinesubc);
310:   PetscFree((*nep)->sc);
311:   /* just in case the initial vectors have not been used */
312:   SlepcBasisDestroy_Private(&(*nep)->nini,&(*nep)->IS);
313:   if ((*nep)->convergeddestroy) {
314:     (*(*nep)->convergeddestroy)((*nep)->convergedctx);
315:   }
316:   NEPMonitorCancel(*nep);
317:   PetscHeaderDestroy(nep);
318:   return(0);
319: }

321: /*@
322:    NEPSetBV - Associates a basis vectors object to the nonlinear eigensolver.

324:    Collective on NEP

326:    Input Parameters:
327: +  nep - eigensolver context obtained from NEPCreate()
328: -  bv  - the basis vectors object

330:    Note:
331:    Use NEPGetBV() to retrieve the basis vectors context (for example,
332:    to free it at the end of the computations).

334:    Level: advanced

336: .seealso: NEPGetBV()
337: @*/
338: PetscErrorCode NEPSetBV(NEP nep,BV bv)
339: {

346:   PetscObjectReference((PetscObject)bv);
347:   BVDestroy(&nep->V);
348:   nep->V = bv;
349:   PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->V);
350:   return(0);
351: }

353: /*@
354:    NEPGetBV - Obtain the basis vectors object associated to the nonlinear
355:    eigensolver object.

357:    Not Collective

359:    Input Parameters:
360: .  nep - eigensolver context obtained from NEPCreate()

362:    Output Parameter:
363: .  bv - basis vectors context

365:    Level: advanced

367: .seealso: NEPSetBV()
368: @*/
369: PetscErrorCode NEPGetBV(NEP nep,BV *bv)
370: {

376:   if (!nep->V) {
377:     BVCreate(PetscObjectComm((PetscObject)nep),&nep->V);
378:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->V);
379:   }
380:   *bv = nep->V;
381:   return(0);
382: }

384: /*@
385:    NEPSetRG - Associates a region object to the nonlinear eigensolver.

387:    Collective on NEP

389:    Input Parameters:
390: +  nep - eigensolver context obtained from NEPCreate()
391: -  rg  - the region object

393:    Note:
394:    Use NEPGetRG() to retrieve the region context (for example,
395:    to free it at the end of the computations).

397:    Level: advanced

399: .seealso: NEPGetRG()
400: @*/
401: PetscErrorCode NEPSetRG(NEP nep,RG rg)
402: {

409:   PetscObjectReference((PetscObject)rg);
410:   RGDestroy(&nep->rg);
411:   nep->rg = rg;
412:   PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->rg);
413:   return(0);
414: }

416: /*@
417:    NEPGetRG - Obtain the region object associated to the
418:    nonlinear eigensolver object.

420:    Not Collective

422:    Input Parameters:
423: .  nep - eigensolver context obtained from NEPCreate()

425:    Output Parameter:
426: .  rg - region context

428:    Level: advanced

430: .seealso: NEPSetRG()
431: @*/
432: PetscErrorCode NEPGetRG(NEP nep,RG *rg)
433: {

439:   if (!nep->rg) {
440:     RGCreate(PetscObjectComm((PetscObject)nep),&nep->rg);
441:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->rg);
442:   }
443:   *rg = nep->rg;
444:   return(0);
445: }

447: /*@
448:    NEPSetDS - Associates a direct solver object to the nonlinear eigensolver.

450:    Collective on NEP

452:    Input Parameters:
453: +  nep - eigensolver context obtained from NEPCreate()
454: -  ds  - the direct solver object

456:    Note:
457:    Use NEPGetDS() to retrieve the direct solver context (for example,
458:    to free it at the end of the computations).

460:    Level: advanced

462: .seealso: NEPGetDS()
463: @*/
464: PetscErrorCode NEPSetDS(NEP nep,DS ds)
465: {

472:   PetscObjectReference((PetscObject)ds);
473:   DSDestroy(&nep->ds);
474:   nep->ds = ds;
475:   PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->ds);
476:   return(0);
477: }

479: /*@
480:    NEPGetDS - Obtain the direct solver object associated to the
481:    nonlinear eigensolver object.

483:    Not Collective

485:    Input Parameters:
486: .  nep - eigensolver context obtained from NEPCreate()

488:    Output Parameter:
489: .  ds - direct solver context

491:    Level: advanced

493: .seealso: NEPSetDS()
494: @*/
495: PetscErrorCode NEPGetDS(NEP nep,DS *ds)
496: {

502:   if (!nep->ds) {
503:     DSCreate(PetscObjectComm((PetscObject)nep),&nep->ds);
504:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->ds);
505:   }
506:   *ds = nep->ds;
507:   return(0);
508: }

510: /*@
511:    NEPRefineGetKSP - Obtain the ksp object used by the eigensolver
512:    object in the refinement phase.

514:    Not Collective

516:    Input Parameters:
517: .  nep - eigensolver context obtained from NEPCreate()

519:    Output Parameter:
520: .  ksp - ksp context

522:    Level: advanced

524: .seealso: NEPSetRefine()
525: @*/
526: PetscErrorCode NEPRefineGetKSP(NEP nep,KSP *ksp)
527: {

533:   if (!nep->refineksp) {
534:     if (nep->npart>1) {
535:       /* Split in subcomunicators */
536:       PetscSubcommCreate(PetscObjectComm((PetscObject)nep),&nep->refinesubc);
537:       PetscSubcommSetNumber(nep->refinesubc,nep->npart);
538:       PetscSubcommSetType(nep->refinesubc,PETSC_SUBCOMM_CONTIGUOUS);
539:       PetscLogObjectMemory((PetscObject)nep,sizeof(PetscSubcomm));
540:     }
541:     KSPCreate((nep->npart==1)?PetscObjectComm((PetscObject)nep):PetscSubcommChild(nep->refinesubc),&nep->refineksp);
542:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->refineksp);
543:     KSPSetOptionsPrefix(*ksp,((PetscObject)nep)->prefix);
544:     KSPAppendOptionsPrefix(*ksp,"nep_refine_");
545:     KSPSetTolerances(nep->refineksp,SLEPC_DEFAULT_TOL,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
546:   }
547:   *ksp = nep->refineksp;
548:   return(0);
549: }

551: /*@
552:    NEPSetTarget - Sets the value of the target.

554:    Logically Collective on NEP

556:    Input Parameters:
557: +  nep    - eigensolver context
558: -  target - the value of the target

560:    Options Database Key:
561: .  -nep_target <scalar> - the value of the target

563:    Notes:
564:    The target is a scalar value used to determine the portion of the spectrum
565:    of interest. It is used in combination with NEPSetWhichEigenpairs().

567:    In the case of complex scalars, a complex value can be provided in the
568:    command line with [+/-][realnumber][+/-]realnumberi with no spaces, e.g.
569:    -nep_target 1.0+2.0i

571:    Level: intermediate

573: .seealso: NEPGetTarget(), NEPSetWhichEigenpairs()
574: @*/
575: PetscErrorCode NEPSetTarget(NEP nep,PetscScalar target)
576: {
580:   nep->target = target;
581:   return(0);
582: }

584: /*@
585:    NEPGetTarget - Gets the value of the target.

587:    Not Collective

589:    Input Parameter:
590: .  nep - eigensolver context

592:    Output Parameter:
593: .  target - the value of the target

595:    Note:
596:    If the target was not set by the user, then zero is returned.

598:    Level: intermediate

600: .seealso: NEPSetTarget()
601: @*/
602: PetscErrorCode NEPGetTarget(NEP nep,PetscScalar* target)
603: {
607:   *target = nep->target;
608:   return(0);
609: }

611: /*@C
612:    NEPSetFunction - Sets the function to compute the nonlinear Function T(lambda)
613:    as well as the location to store the matrix.

615:    Logically Collective on NEP and Mat

617:    Input Parameters:
618: +  nep - the NEP context
619: .  A   - Function matrix
620: .  B   - preconditioner matrix (usually same as the Function)
621: .  fun - Function evaluation routine (if NULL then NEP retains any
622:          previously set value)
623: -  ctx - [optional] user-defined context for private data for the Function
624:          evaluation routine (may be NULL) (if NULL then NEP retains any
625:          previously set value)

627:    Calling Sequence of fun:
628: $   fun(NEP nep,PetscScalar lambda,Mat F,Mat P,void *ctx)

630: +  nep    - the NEP context
631: .  lambda - the scalar argument where T(.) must be evaluated
632: .  T      - matrix that will contain T(lambda)
633: .  P      - (optional) different matrix to build the preconditioner
634: -  ctx    - (optional) user-defined context, as set by NEPSetFunction()

636:    Level: beginner

638: .seealso: NEPGetFunction(), NEPSetJacobian()
639: @*/
640: PetscErrorCode NEPSetFunction(NEP nep,Mat A,Mat B,PetscErrorCode (*fun)(NEP,PetscScalar,Mat,Mat,void*),void *ctx)
641: {


651:   if (nep->state) { NEPReset(nep); }
652:   else if (nep->fui && nep->fui!=NEP_USER_INTERFACE_CALLBACK) { NEPReset_Problem(nep); }

654:   if (fun) nep->computefunction = fun;
655:   if (ctx) nep->functionctx     = ctx;
656:   if (A) {
657:     PetscObjectReference((PetscObject)A);
658:     MatDestroy(&nep->function);
659:     nep->function = A;
660:   }
661:   if (B) {
662:     PetscObjectReference((PetscObject)B);
663:     MatDestroy(&nep->function_pre);
664:     nep->function_pre = B;
665:   }
666:   nep->fui   = NEP_USER_INTERFACE_CALLBACK;
667:   nep->state = NEP_STATE_INITIAL;
668:   return(0);
669: }

671: /*@C
672:    NEPGetFunction - Returns the Function matrix and optionally the user
673:    provided context for evaluating the Function.

675:    Not Collective, but Mat object will be parallel if NEP object is

677:    Input Parameter:
678: .  nep - the nonlinear eigensolver context

680:    Output Parameters:
681: +  A   - location to stash Function matrix (or NULL)
682: .  B   - location to stash preconditioner matrix (or NULL)
683: .  fun - location to put Function function (or NULL)
684: -  ctx - location to stash Function context (or NULL)

686:    Level: advanced

688: .seealso: NEPSetFunction()
689: @*/
690: PetscErrorCode NEPGetFunction(NEP nep,Mat *A,Mat *B,PetscErrorCode (**fun)(NEP,PetscScalar,Mat,Mat,void*),void **ctx)
691: {
694:   NEPCheckCallback(nep,1);
695:   if (A)   *A   = nep->function;
696:   if (B)   *B   = nep->function_pre;
697:   if (fun) *fun = nep->computefunction;
698:   if (ctx) *ctx = nep->functionctx;
699:   return(0);
700: }

702: /*@C
703:    NEPSetJacobian - Sets the function to compute Jacobian T'(lambda) as well
704:    as the location to store the matrix.

706:    Logically Collective on NEP and Mat

708:    Input Parameters:
709: +  nep - the NEP context
710: .  A   - Jacobian matrix
711: .  jac - Jacobian evaluation routine (if NULL then NEP retains any
712:          previously set value)
713: -  ctx - [optional] user-defined context for private data for the Jacobian
714:          evaluation routine (may be NULL) (if NULL then NEP retains any
715:          previously set value)

717:    Calling Sequence of jac:
718: $   jac(NEP nep,PetscScalar lambda,Mat J,void *ctx)

720: +  nep    - the NEP context
721: .  lambda - the scalar argument where T'(.) must be evaluated
722: .  J      - matrix that will contain T'(lambda)
723: -  ctx    - (optional) user-defined context, as set by NEPSetJacobian()

725:    Level: beginner

727: .seealso: NEPSetFunction(), NEPGetJacobian()
728: @*/
729: PetscErrorCode NEPSetJacobian(NEP nep,Mat A,PetscErrorCode (*jac)(NEP,PetscScalar,Mat,void*),void *ctx)
730: {


738:   if (nep->state) { NEPReset(nep); }
739:   else if (nep->fui && nep->fui!=NEP_USER_INTERFACE_CALLBACK) { NEPReset_Problem(nep); }

741:   if (jac) nep->computejacobian = jac;
742:   if (ctx) nep->jacobianctx     = ctx;
743:   if (A) {
744:     PetscObjectReference((PetscObject)A);
745:     MatDestroy(&nep->jacobian);
746:     nep->jacobian = A;
747:   }
748:   nep->fui   = NEP_USER_INTERFACE_CALLBACK;
749:   nep->state = NEP_STATE_INITIAL;
750:   return(0);
751: }

753: /*@C
754:    NEPGetJacobian - Returns the Jacobian matrix and optionally the user
755:    provided routine and context for evaluating the Jacobian.

757:    Not Collective, but Mat object will be parallel if NEP object is

759:    Input Parameter:
760: .  nep - the nonlinear eigensolver context

762:    Output Parameters:
763: +  A   - location to stash Jacobian matrix (or NULL)
764: .  jac - location to put Jacobian function (or NULL)
765: -  ctx - location to stash Jacobian context (or NULL)

767:    Level: advanced

769: .seealso: NEPSetJacobian()
770: @*/
771: PetscErrorCode NEPGetJacobian(NEP nep,Mat *A,PetscErrorCode (**jac)(NEP,PetscScalar,Mat,void*),void **ctx)
772: {
775:   NEPCheckCallback(nep,1);
776:   if (A)   *A   = nep->jacobian;
777:   if (jac) *jac = nep->computejacobian;
778:   if (ctx) *ctx = nep->jacobianctx;
779:   return(0);
780: }

782: /*@
783:    NEPSetSplitOperator - Sets the operator of the nonlinear eigenvalue problem
784:    in split form.

786:    Collective on NEP, Mat and FN

788:    Input Parameters:
789: +  nep - the nonlinear eigensolver context
790: .  n   - number of terms in the split form
791: .  A   - array of matrices
792: .  f   - array of functions
793: -  str - structure flag for matrices

795:    Notes:
796:    The nonlinear operator is written as T(lambda) = sum_i A_i*f_i(lambda),
797:    for i=1,...,n. The derivative T'(lambda) can be obtained using the
798:    derivatives of f_i.

800:    The structure flag provides information about A_i's nonzero pattern
801:    (see MatStructure enum). If all matrices have the same pattern, then
802:    use SAME_NONZERO_PATTERN. If the patterns are different but contained
803:    in the pattern of the first one, then use SUBSET_NONZERO_PATTERN.
804:    Otherwise use DIFFERENT_NONZERO_PATTERN.

806:    This function must be called before NEPSetUp(). If it is called again
807:    after NEPSetUp() then the NEP object is reset.

809:    Level: beginner

811: .seealso: NEPGetSplitOperatorTerm(), NEPGetSplitOperatorInfo()
812:  @*/
813: PetscErrorCode NEPSetSplitOperator(NEP nep,PetscInt n,Mat A[],FN f[],MatStructure str)
814: {
815:   PetscInt       i;

821:   if (n <= 0) SETERRQ1(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"Must have one or more terms, you have %D",n);
826:   if (nep->state) { NEPReset(nep); }
827:   else { NEPReset_Problem(nep); }

829:   /* allocate space and copy matrices and functions */
830:   PetscMalloc1(n,&nep->A);
831:   PetscLogObjectMemory((PetscObject)nep,n*sizeof(Mat));
832:   for (i=0;i<n;i++) {
834:     PetscObjectReference((PetscObject)A[i]);
835:     nep->A[i] = A[i];
836:   }
837:   PetscMalloc1(n,&nep->f);
838:   PetscLogObjectMemory((PetscObject)nep,n*sizeof(FN));
839:   for (i=0;i<n;i++) {
841:     PetscObjectReference((PetscObject)f[i]);
842:     nep->f[i] = f[i];
843:   }
844:   PetscCalloc1(n,&nep->nrma);
845:   PetscLogObjectMemory((PetscObject)nep,n*sizeof(PetscReal));
846:   nep->nt    = n;
847:   nep->mstr  = str;
848:   nep->fui   = NEP_USER_INTERFACE_SPLIT;
849:   nep->state = NEP_STATE_INITIAL;
850:   return(0);
851: }

853: /*@
854:    NEPGetSplitOperatorTerm - Gets the matrices and functions associated with
855:    the nonlinear operator in split form.

857:    Not collective, though parallel Mats and FNs are returned if the NEP is parallel

859:    Input Parameter:
860: +  nep - the nonlinear eigensolver context
861: -  k   - the index of the requested term (starting in 0)

863:    Output Parameters:
864: +  A - the matrix of the requested term
865: -  f - the function of the requested term

867:    Level: intermediate

869: .seealso: NEPSetSplitOperator(), NEPGetSplitOperatorInfo()
870: @*/
871: PetscErrorCode NEPGetSplitOperatorTerm(NEP nep,PetscInt k,Mat *A,FN *f)
872: {
875:   NEPCheckSplit(nep,1);
876:   if (k<0 || k>=nep->nt) SETERRQ1(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"k must be between 0 and %D",nep->nt-1);
877:   if (A) *A = nep->A[k];
878:   if (f) *f = nep->f[k];
879:   return(0);
880: }

882: /*@
883:    NEPGetSplitOperatorInfo - Returns the number of terms of the split form of
884:    the nonlinear operator, as well as the structure flag for matrices.

886:    Not collective

888:    Input Parameter:
889: .  nep - the nonlinear eigensolver context

891:    Output Parameters:
892: +  n   - the number of terms passed in NEPSetSplitOperator()
893: -  str - the matrix structure flag passed in NEPSetSplitOperator()

895:    Level: intermediate

897: .seealso: NEPSetSplitOperator(), NEPGetSplitOperatorTerm()
898: @*/
899: PetscErrorCode NEPGetSplitOperatorInfo(NEP nep,PetscInt *n,MatStructure *str)
900: {
903:   NEPCheckSplit(nep,1);
904:   if (n)   *n = nep->nt;
905:   if (str) *str = nep->mstr;
906:   return(0);
907: }

909: /*@C
910:    NEPSetDerivatives - Sets the function to compute the k-th derivative T^(k)(lambda)
911:    for any value of k (including 0), as well as the location to store the matrix.

913:    Logically Collective on NEP and Mat

915:    Input Parameters:
916: +  nep - the NEP context
917: .  A   - the matrix to store the computed derivative
918: .  der - routing to evaluate the k-th derivative (if NULL then NEP retains any
919:          previously set value)
920: -  ctx - [optional] user-defined context for private data for the derivatives
921:          evaluation routine (may be NULL) (if NULL then NEP retains any
922:          previously set value)

924:    Level: beginner

926: .seealso: NEPSetFunction(), NEPGetDerivatives()
927: @*/
928: PetscErrorCode NEPSetDerivatives(NEP nep,Mat A,PetscErrorCode (*der)(NEP,PetscScalar,PetscInt,Mat,void*),void *ctx)
929: {


937:   if (nep->state) { NEPReset(nep); }
938:   else { NEPReset_Problem(nep); }

940:   if (der) nep->computederivatives = der;
941:   if (ctx) nep->derivativesctx     = ctx;
942:   if (A) {
943:     PetscObjectReference((PetscObject)A);
944:     MatDestroy(&nep->derivatives);
945:     nep->derivatives = A;
946:   }
947:   nep->fui   = NEP_USER_INTERFACE_DERIVATIVES;
948:   nep->state = NEP_STATE_INITIAL;
949:   return(0);
950: }

952: /*@C
953:    NEPGetDerivatives - Returns the derivatives matrix and optionally the user
954:    provided routine and context for evaluating the derivatives.

956:    Not Collective, but Mat object will be parallel if NEP object is

958:    Input Parameter:
959: .  nep - the nonlinear eigensolver context

961:    Output Parameters:
962: +  A   - location to stash the derivatives matrix (or NULL)
963: .  der - location to put derivatives function (or NULL)
964: -  ctx - location to stash derivatives context (or NULL)

966:    Level: advanced

968: .seealso: NEPSetDerivatives()
969: @*/
970: PetscErrorCode NEPGetDerivatives(NEP nep,Mat *A,PetscErrorCode (**der)(NEP,PetscScalar,PetscInt,Mat,void*),void **ctx)
971: {
974:   NEPCheckDerivatives(nep,1);
975:   if (A)   *A   = nep->derivatives;
976:   if (der) *der = nep->computederivatives;
977:   if (ctx) *ctx = nep->derivativesctx;
978:   return(0);
979: }