Date: 2021-02-01T14:42:15+00:00

Actual source code: nepbasic.c
slepc-3.14.2 2021-02-01
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2020, 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>

     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_Resolvent = 0;

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

     24:    Collective

     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          = PETSC_DEFAULT;
     48:   nep->nev             = 1;
     49:   nep->ncv             = PETSC_DEFAULT;
     50:   nep->mpd             = PETSC_DEFAULT;
     51:   nep->nini            = 0;
     52:   nep->target          = 0.0;
     53:   nep->tol             = PETSC_DEFAULT;
     54:   nep->conv            = NEP_CONV_NORM;
     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;
     64:   nep->twosided        = PETSC_FALSE;

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

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

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

    111:   PetscNewLog(nep,&nep->sc);
    112:   *outnep = nep;
    113:   return(0);
    114: }

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

    119:    Logically Collective on nep

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

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

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

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

    140:    Level: intermediate

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

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

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

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

    162:   nep->state = NEP_STATE_INITIAL;
    163:   PetscObjectChangeTypeName((PetscObject)nep,type);
    164:   (*r)(nep);
    165:   return(0);
    166: }

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

    171:    Not Collective

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

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

    179:    Level: intermediate

    181: .seealso: NEPSetType()
    182: @*/
    183: PetscErrorCode NEPGetType(NEP nep,NEPType *type)
    184: {
    188:   *type = ((PetscObject)nep)->type_name;
    189:   return(0);
    190: }

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

    195:    Not Collective

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

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

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

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

    214:    Level: advanced

    216: .seealso: NEPRegisterAll()
    217: @*/
    218: PetscErrorCode NEPRegister(const char *name,PetscErrorCode (*function)(NEP))
    219: {

    223:   NEPInitializePackage();
    224:   PetscFunctionListAdd(&NEPList,name,function);
    225:   return(0);
    226: }

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

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

    256:    Collective on nep

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

    261:    Level: advanced

    263: .seealso: NEPDestroy()
    264: @*/
    265: PetscErrorCode NEPReset(NEP nep)
    266: {

    271:   if (!nep) return(0);
    272:   if (nep->ops->reset) { (nep->ops->reset)(nep); }
    273:   if (nep->refineksp) { KSPReset(nep->refineksp); }
    274:   NEPReset_Problem(nep);
    275:   BVDestroy(&nep->V);
    276:   BVDestroy(&nep->W);
    277:   VecDestroyVecs(nep->nwork,&nep->work);
    278:   MatDestroy(&nep->resolvent);
    279:   nep->nwork = 0;
    280:   nep->state = NEP_STATE_INITIAL;
    281:   return(0);
    282: }

    284: /*@
    285:    NEPDestroy - Destroys the NEP context.

    287:    Collective on nep

    289:    Input Parameter:
    290: .  nep - eigensolver context obtained from NEPCreate()

    292:    Level: beginner

    294: .seealso: NEPCreate(), NEPSetUp(), NEPSolve()
    295: @*/
    296: PetscErrorCode NEPDestroy(NEP *nep)
    297: {

    301:   if (!*nep) return(0);
    303:   if (--((PetscObject)(*nep))->refct > 0) { *nep = 0; return(0); }
    304:   NEPReset(*nep);
    305:   if ((*nep)->ops->destroy) { (*(*nep)->ops->destroy)(*nep); }
    306:   if ((*nep)->eigr) {
    307:     PetscFree4((*nep)->eigr,(*nep)->eigi,(*nep)->errest,(*nep)->perm);
    308:   }
    309:   RGDestroy(&(*nep)->rg);
    310:   DSDestroy(&(*nep)->ds);
    311:   KSPDestroy(&(*nep)->refineksp);
    312:   PetscSubcommDestroy(&(*nep)->refinesubc);
    313:   PetscFree((*nep)->sc);
    314:   /* just in case the initial vectors have not been used */
    315:   SlepcBasisDestroy_Private(&(*nep)->nini,&(*nep)->IS);
    316:   if ((*nep)->convergeddestroy) {
    317:     (*(*nep)->convergeddestroy)((*nep)->convergedctx);
    318:   }
    319:   NEPMonitorCancel(*nep);
    320:   PetscHeaderDestroy(nep);
    321:   return(0);
    322: }

    324: /*@
    325:    NEPSetBV - Associates a basis vectors object to the nonlinear eigensolver.

    327:    Collective on nep

    329:    Input Parameters:
    330: +  nep - eigensolver context obtained from NEPCreate()
    331: -  bv  - the basis vectors object

    333:    Note:
    334:    Use NEPGetBV() to retrieve the basis vectors context (for example,
    335:    to free it at the end of the computations).

    337:    Level: advanced

    339: .seealso: NEPGetBV()
    340: @*/
    341: PetscErrorCode NEPSetBV(NEP nep,BV bv)
    342: {

    349:   PetscObjectReference((PetscObject)bv);
    350:   BVDestroy(&nep->V);
    351:   nep->V = bv;
    352:   PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->V);
    353:   return(0);
    354: }

    356: /*@
    357:    NEPGetBV - Obtain the basis vectors object associated to the nonlinear
    358:    eigensolver object.

    360:    Not Collective

    362:    Input Parameters:
    363: .  nep - eigensolver context obtained from NEPCreate()

    365:    Output Parameter:
    366: .  bv - basis vectors context

    368:    Level: advanced

    370: .seealso: NEPSetBV()
    371: @*/
    372: PetscErrorCode NEPGetBV(NEP nep,BV *bv)
    373: {

    379:   if (!nep->V) {
    380:     BVCreate(PetscObjectComm((PetscObject)nep),&nep->V);
    381:     PetscObjectIncrementTabLevel((PetscObject)nep->V,(PetscObject)nep,0);
    382:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->V);
    383:     PetscObjectSetOptions((PetscObject)nep->V,((PetscObject)nep)->options);
    384:   }
    385:   *bv = nep->V;
    386:   return(0);
    387: }

    389: /*@
    390:    NEPSetRG - Associates a region object to the nonlinear eigensolver.

    392:    Collective on nep

    394:    Input Parameters:
    395: +  nep - eigensolver context obtained from NEPCreate()
    396: -  rg  - the region object

    398:    Note:
    399:    Use NEPGetRG() to retrieve the region context (for example,
    400:    to free it at the end of the computations).

    402:    Level: advanced

    404: .seealso: NEPGetRG()
    405: @*/
    406: PetscErrorCode NEPSetRG(NEP nep,RG rg)
    407: {

    414:   PetscObjectReference((PetscObject)rg);
    415:   RGDestroy(&nep->rg);
    416:   nep->rg = rg;
    417:   PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->rg);
    418:   return(0);
    419: }

    421: /*@
    422:    NEPGetRG - Obtain the region object associated to the
    423:    nonlinear eigensolver object.

    425:    Not Collective

    427:    Input Parameters:
    428: .  nep - eigensolver context obtained from NEPCreate()

    430:    Output Parameter:
    431: .  rg - region context

    433:    Level: advanced

    435: .seealso: NEPSetRG()
    436: @*/
    437: PetscErrorCode NEPGetRG(NEP nep,RG *rg)
    438: {

    444:   if (!nep->rg) {
    445:     RGCreate(PetscObjectComm((PetscObject)nep),&nep->rg);
    446:     PetscObjectIncrementTabLevel((PetscObject)nep->rg,(PetscObject)nep,0);
    447:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->rg);
    448:     PetscObjectSetOptions((PetscObject)nep->rg,((PetscObject)nep)->options);
    449:   }
    450:   *rg = nep->rg;
    451:   return(0);
    452: }

    454: /*@
    455:    NEPSetDS - Associates a direct solver object to the nonlinear eigensolver.

    457:    Collective on nep

    459:    Input Parameters:
    460: +  nep - eigensolver context obtained from NEPCreate()
    461: -  ds  - the direct solver object

    463:    Note:
    464:    Use NEPGetDS() to retrieve the direct solver context (for example,
    465:    to free it at the end of the computations).

    467:    Level: advanced

    469: .seealso: NEPGetDS()
    470: @*/
    471: PetscErrorCode NEPSetDS(NEP nep,DS ds)
    472: {

    479:   PetscObjectReference((PetscObject)ds);
    480:   DSDestroy(&nep->ds);
    481:   nep->ds = ds;
    482:   PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->ds);
    483:   return(0);
    484: }

    486: /*@
    487:    NEPGetDS - Obtain the direct solver object associated to the
    488:    nonlinear eigensolver object.

    490:    Not Collective

    492:    Input Parameters:
    493: .  nep - eigensolver context obtained from NEPCreate()

    495:    Output Parameter:
    496: .  ds - direct solver context

    498:    Level: advanced

    500: .seealso: NEPSetDS()
    501: @*/
    502: PetscErrorCode NEPGetDS(NEP nep,DS *ds)
    503: {

    509:   if (!nep->ds) {
    510:     DSCreate(PetscObjectComm((PetscObject)nep),&nep->ds);
    511:     PetscObjectIncrementTabLevel((PetscObject)nep->ds,(PetscObject)nep,0);
    512:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->ds);
    513:     PetscObjectSetOptions((PetscObject)nep->ds,((PetscObject)nep)->options);
    514:   }
    515:   *ds = nep->ds;
    516:   return(0);
    517: }

    519: /*@
    520:    NEPRefineGetKSP - Obtain the ksp object used by the eigensolver
    521:    object in the refinement phase.

    523:    Not Collective

    525:    Input Parameters:
    526: .  nep - eigensolver context obtained from NEPCreate()

    528:    Output Parameter:
    529: .  ksp - ksp context

    531:    Level: advanced

    533: .seealso: NEPSetRefine()
    534: @*/
    535: PetscErrorCode NEPRefineGetKSP(NEP nep,KSP *ksp)
    536: {

    542:   if (!nep->refineksp) {
    543:     if (nep->npart>1) {
    544:       /* Split in subcomunicators */
    545:       PetscSubcommCreate(PetscObjectComm((PetscObject)nep),&nep->refinesubc);
    546:       PetscSubcommSetNumber(nep->refinesubc,nep->npart);
    547:       PetscSubcommSetType(nep->refinesubc,PETSC_SUBCOMM_CONTIGUOUS);
    548:       PetscLogObjectMemory((PetscObject)nep,sizeof(PetscSubcomm));
    549:     }
    550:     KSPCreate((nep->npart==1)?PetscObjectComm((PetscObject)nep):PetscSubcommChild(nep->refinesubc),&nep->refineksp);
    551:     PetscObjectIncrementTabLevel((PetscObject)nep->refineksp,(PetscObject)nep,0);
    552:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->refineksp);
    553:     PetscObjectSetOptions((PetscObject)nep->refineksp,((PetscObject)nep)->options);
    554:     KSPSetOptionsPrefix(*ksp,((PetscObject)nep)->prefix);
    555:     KSPAppendOptionsPrefix(*ksp,"nep_refine_");
    556:     KSPSetTolerances(nep->refineksp,SLEPC_DEFAULT_TOL,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
    557:   }
    558:   *ksp = nep->refineksp;
    559:   return(0);
    560: }

    562: /*@
    563:    NEPSetTarget - Sets the value of the target.

    565:    Logically Collective on nep

    567:    Input Parameters:
    568: +  nep    - eigensolver context
    569: -  target - the value of the target

    571:    Options Database Key:
    572: .  -nep_target <scalar> - the value of the target

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

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

    582:    Level: intermediate

    584: .seealso: NEPGetTarget(), NEPSetWhichEigenpairs()
    585: @*/
    586: PetscErrorCode NEPSetTarget(NEP nep,PetscScalar target)
    587: {
    591:   nep->target = target;
    592:   return(0);
    593: }

    595: /*@
    596:    NEPGetTarget - Gets the value of the target.

    598:    Not Collective

    600:    Input Parameter:
    601: .  nep - eigensolver context

    603:    Output Parameter:
    604: .  target - the value of the target

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

    609:    Level: intermediate

    611: .seealso: NEPSetTarget()
    612: @*/
    613: PetscErrorCode NEPGetTarget(NEP nep,PetscScalar* target)
    614: {
    618:   *target = nep->target;
    619:   return(0);
    620: }

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

    626:    Logically Collective on nep

    628:    Input Parameters:
    629: +  nep - the NEP context
    630: .  A   - Function matrix
    631: .  B   - preconditioner matrix (usually same as the Function)
    632: .  fun - Function evaluation routine (if NULL then NEP retains any
    633:          previously set value)
    634: -  ctx - [optional] user-defined context for private data for the Function
    635:          evaluation routine (may be NULL) (if NULL then NEP retains any
    636:          previously set value)

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

    641: +  nep    - the NEP context
    642: .  lambda - the scalar argument where T(.) must be evaluated
    643: .  T      - matrix that will contain T(lambda)
    644: .  P      - (optional) different matrix to build the preconditioner
    645: -  ctx    - (optional) user-defined context, as set by NEPSetFunction()

    647:    Level: beginner

    649: .seealso: NEPGetFunction(), NEPSetJacobian()
    650: @*/
    651: PetscErrorCode NEPSetFunction(NEP nep,Mat A,Mat B,PetscErrorCode (*fun)(NEP,PetscScalar,Mat,Mat,void*),void *ctx)
    652: {

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

    665:   if (fun) nep->computefunction = fun;
    666:   if (ctx) nep->functionctx     = ctx;
    667:   if (A) {
    668:     PetscObjectReference((PetscObject)A);
    669:     MatDestroy(&nep->function);
    670:     nep->function = A;
    671:   }
    672:   if (B) {
    673:     PetscObjectReference((PetscObject)B);
    674:     MatDestroy(&nep->function_pre);
    675:     nep->function_pre = B;
    676:   }
    677:   nep->fui   = NEP_USER_INTERFACE_CALLBACK;
    678:   nep->state = NEP_STATE_INITIAL;
    679:   return(0);
    680: }

    682: /*@C
    683:    NEPGetFunction - Returns the Function matrix and optionally the user
    684:    provided context for evaluating the Function.

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

    688:    Input Parameter:
    689: .  nep - the nonlinear eigensolver context

    691:    Output Parameters:
    692: +  A   - location to stash Function matrix (or NULL)
    693: .  B   - location to stash preconditioner matrix (or NULL)
    694: .  fun - location to put Function function (or NULL)
    695: -  ctx - location to stash Function context (or NULL)

    697:    Level: advanced

    699: .seealso: NEPSetFunction()
    700: @*/
    701: PetscErrorCode NEPGetFunction(NEP nep,Mat *A,Mat *B,PetscErrorCode (**fun)(NEP,PetscScalar,Mat,Mat,void*),void **ctx)
    702: {
    705:   NEPCheckCallback(nep,1);
    706:   if (A)   *A   = nep->function;
    707:   if (B)   *B   = nep->function_pre;
    708:   if (fun) *fun = nep->computefunction;
    709:   if (ctx) *ctx = nep->functionctx;
    710:   return(0);
    711: }

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

    717:    Logically Collective on nep

    719:    Input Parameters:
    720: +  nep - the NEP context
    721: .  A   - Jacobian matrix
    722: .  jac - Jacobian evaluation routine (if NULL then NEP retains any
    723:          previously set value)
    724: -  ctx - [optional] user-defined context for private data for the Jacobian
    725:          evaluation routine (may be NULL) (if NULL then NEP retains any
    726:          previously set value)

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

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

    736:    Level: beginner

    738: .seealso: NEPSetFunction(), NEPGetJacobian()
    739: @*/
    740: PetscErrorCode NEPSetJacobian(NEP nep,Mat A,PetscErrorCode (*jac)(NEP,PetscScalar,Mat,void*),void *ctx)
    741: {

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

    752:   if (jac) nep->computejacobian = jac;
    753:   if (ctx) nep->jacobianctx     = ctx;
    754:   if (A) {
    755:     PetscObjectReference((PetscObject)A);
    756:     MatDestroy(&nep->jacobian);
    757:     nep->jacobian = A;
    758:   }
    759:   nep->fui   = NEP_USER_INTERFACE_CALLBACK;
    760:   nep->state = NEP_STATE_INITIAL;
    761:   return(0);
    762: }

    764: /*@C
    765:    NEPGetJacobian - Returns the Jacobian matrix and optionally the user
    766:    provided routine and context for evaluating the Jacobian.

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

    770:    Input Parameter:
    771: .  nep - the nonlinear eigensolver context

    773:    Output Parameters:
    774: +  A   - location to stash Jacobian matrix (or NULL)
    775: .  jac - location to put Jacobian function (or NULL)
    776: -  ctx - location to stash Jacobian context (or NULL)

    778:    Level: advanced

    780: .seealso: NEPSetJacobian()
    781: @*/
    782: PetscErrorCode NEPGetJacobian(NEP nep,Mat *A,PetscErrorCode (**jac)(NEP,PetscScalar,Mat,void*),void **ctx)
    783: {
    786:   NEPCheckCallback(nep,1);
    787:   if (A)   *A   = nep->jacobian;
    788:   if (jac) *jac = nep->computejacobian;
    789:   if (ctx) *ctx = nep->jacobianctx;
    790:   return(0);
    791: }

    793: /*@
    794:    NEPSetSplitOperator - Sets the operator of the nonlinear eigenvalue problem
    795:    in split form.

    797:    Collective on nep

    799:    Input Parameters:
    800: +  nep - the nonlinear eigensolver context
    801: .  n   - number of terms in the split form
    802: .  A   - array of matrices
    803: .  f   - array of functions
    804: -  str - structure flag for matrices

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

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

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

    820:    Level: beginner

    822: .seealso: NEPGetSplitOperatorTerm(), NEPGetSplitOperatorInfo()
    823:  @*/
    824: PetscErrorCode NEPSetSplitOperator(NEP nep,PetscInt n,Mat A[],FN f[],MatStructure str)
    825: {
    826:   PetscInt       i;

    832:   if (n <= 0) SETERRQ1(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"Must have one or more terms, you have %D",n);

    838:   for (i=0;i<n;i++) {
    841:     PetscObjectReference((PetscObject)A[i]);
    842:     PetscObjectReference((PetscObject)f[i]);
    843:   }

    845:   if (nep->state) { NEPReset(nep); }
    846:   else { NEPReset_Problem(nep); }

    848:   /* allocate space and copy matrices and functions */
    849:   PetscMalloc1(n,&nep->A);
    850:   PetscLogObjectMemory((PetscObject)nep,n*sizeof(Mat));
    851:   for (i=0;i<n;i++) nep->A[i] = A[i];
    852:   PetscMalloc1(n,&nep->f);
    853:   PetscLogObjectMemory((PetscObject)nep,n*sizeof(FN));
    854:   for (i=0;i<n;i++) nep->f[i] = f[i];
    855:   PetscCalloc1(n,&nep->nrma);
    856:   PetscLogObjectMemory((PetscObject)nep,n*sizeof(PetscReal));
    857:   nep->nt    = n;
    858:   nep->mstr  = str;
    859:   nep->fui   = NEP_USER_INTERFACE_SPLIT;
    860:   nep->state = NEP_STATE_INITIAL;
    861:   return(0);
    862: }

    864: /*@
    865:    NEPGetSplitOperatorTerm - Gets the matrices and functions associated with
    866:    the nonlinear operator in split form.

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

    870:    Input Parameter:
    871: +  nep - the nonlinear eigensolver context
    872: -  k   - the index of the requested term (starting in 0)

    874:    Output Parameters:
    875: +  A - the matrix of the requested term
    876: -  f - the function of the requested term

    878:    Level: intermediate

    880: .seealso: NEPSetSplitOperator(), NEPGetSplitOperatorInfo()
    881: @*/
    882: PetscErrorCode NEPGetSplitOperatorTerm(NEP nep,PetscInt k,Mat *A,FN *f)
    883: {
    886:   NEPCheckSplit(nep,1);
    887:   if (k<0 || k>=nep->nt) SETERRQ1(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"k must be between 0 and %D",nep->nt-1);
    888:   if (A) *A = nep->A[k];
    889:   if (f) *f = nep->f[k];
    890:   return(0);
    891: }

    893: /*@
    894:    NEPGetSplitOperatorInfo - Returns the number of terms of the split form of
    895:    the nonlinear operator, as well as the structure flag for matrices.

    897:    Not collective

    899:    Input Parameter:
    900: .  nep - the nonlinear eigensolver context

    902:    Output Parameters:
    903: +  n   - the number of terms passed in NEPSetSplitOperator()
    904: -  str - the matrix structure flag passed in NEPSetSplitOperator()

    906:    Level: intermediate

    908: .seealso: NEPSetSplitOperator(), NEPGetSplitOperatorTerm()
    909: @*/
    910: PetscErrorCode NEPGetSplitOperatorInfo(NEP nep,PetscInt *n,MatStructure *str)
    911: {
    914:   NEPCheckSplit(nep,1);
    915:   if (n)   *n = nep->nt;
    916:   if (str) *str = nep->mstr;
    917:   return(0);
    918: }