Date: 2023-09-05T10:18:28+00:00

Actual source code: pepopts.c
slepc-3.19.2 2023-09-05
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, 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:    PEP routines related to options that can be set via the command-line
     12:    or procedurally
     13: */

     15: #include <slepc/private/pepimpl.h>
     16: #include <petscdraw.h>

     18: /*@C
     19:    PEPMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type
     20:    indicated by the user.

     22:    Collective

     24:    Input Parameters:
     25: +  pep      - the polynomial eigensolver context
     26: .  opt      - the command line option for this monitor
     27: .  name     - the monitor type one is seeking
     28: .  ctx      - an optional user context for the monitor, or NULL
     29: -  trackall - whether this monitor tracks all eigenvalues or not

     31:    Level: developer

     33: .seealso: PEPMonitorSet(), PEPSetTrackAll()
     34: @*/
     35: PetscErrorCode PEPMonitorSetFromOptions(PEP pep,const char opt[],const char name[],void *ctx,PetscBool trackall)
     36: {
     37:   PetscErrorCode       (*mfunc)(PEP,PetscInt,PetscInt,PetscScalar*,PetscScalar*,PetscReal*,PetscInt,void*);
     38:   PetscErrorCode       (*cfunc)(PetscViewer,PetscViewerFormat,void*,PetscViewerAndFormat**);
     39:   PetscErrorCode       (*dfunc)(PetscViewerAndFormat**);
     40:   PetscViewerAndFormat *vf;
     41:   PetscViewer          viewer;
     42:   PetscViewerFormat    format;
     43:   PetscViewerType      vtype;
     44:   char                 key[PETSC_MAX_PATH_LEN];
     45:   PetscBool            flg;

     47:   PetscFunctionBegin;
     48:   PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)pep),((PetscObject)pep)->options,((PetscObject)pep)->prefix,opt,&viewer,&format,&flg));
     49:   if (!flg) PetscFunctionReturn(PETSC_SUCCESS);

     51:   PetscCall(PetscViewerGetType(viewer,&vtype));
     52:   PetscCall(SlepcMonitorMakeKey_Internal(name,vtype,format,key));
     53:   PetscCall(PetscFunctionListFind(PEPMonitorList,key,&mfunc));
     54:   PetscCheck(mfunc,PetscObjectComm((PetscObject)pep),PETSC_ERR_SUP,"Specified viewer and format not supported");
     55:   PetscCall(PetscFunctionListFind(PEPMonitorCreateList,key,&cfunc));
     56:   PetscCall(PetscFunctionListFind(PEPMonitorDestroyList,key,&dfunc));
     57:   if (!cfunc) cfunc = PetscViewerAndFormatCreate_Internal;
     58:   if (!dfunc) dfunc = PetscViewerAndFormatDestroy;

     60:   PetscCall((*cfunc)(viewer,format,ctx,&vf));
     61:   PetscCall(PetscObjectDereference((PetscObject)viewer));
     62:   PetscCall(PEPMonitorSet(pep,mfunc,vf,(PetscErrorCode(*)(void **))dfunc));
     63:   if (trackall) PetscCall(PEPSetTrackAll(pep,PETSC_TRUE));
     64:   PetscFunctionReturn(PETSC_SUCCESS);
     65: }

     67: /*@
     68:    PEPSetFromOptions - Sets PEP options from the options database.
     69:    This routine must be called before PEPSetUp() if the user is to be
     70:    allowed to set the solver type.

     72:    Collective

     74:    Input Parameters:
     75: .  pep - the polynomial eigensolver context

     77:    Notes:
     78:    To see all options, run your program with the -help option.

     80:    Level: beginner

     82: .seealso: PEPSetOptionsPrefix()
     83: @*/
     84: PetscErrorCode PEPSetFromOptions(PEP pep)
     85: {
     86:   char            type[256];
     87:   PetscBool       set,flg,flg1,flg2,flg3,flg4,flg5;
     88:   PetscReal       r,t,array[2]={0,0};
     89:   PetscScalar     s;
     90:   PetscInt        i,j,k;
     91:   PEPScale        scale;
     92:   PEPRefine       refine;
     93:   PEPRefineScheme scheme;

     95:   PetscFunctionBegin;
     97:   PetscCall(PEPRegisterAll());
     98:   PetscObjectOptionsBegin((PetscObject)pep);
     99:     PetscCall(PetscOptionsFList("-pep_type","Polynomial eigensolver method","PEPSetType",PEPList,(char*)(((PetscObject)pep)->type_name?((PetscObject)pep)->type_name:PEPTOAR),type,sizeof(type),&flg));
    100:     if (flg) PetscCall(PEPSetType(pep,type));
    101:     else if (!((PetscObject)pep)->type_name) PetscCall(PEPSetType(pep,PEPTOAR));

    103:     PetscCall(PetscOptionsBoolGroupBegin("-pep_general","General polynomial eigenvalue problem","PEPSetProblemType",&flg));
    104:     if (flg) PetscCall(PEPSetProblemType(pep,PEP_GENERAL));
    105:     PetscCall(PetscOptionsBoolGroup("-pep_hermitian","Hermitian polynomial eigenvalue problem","PEPSetProblemType",&flg));
    106:     if (flg) PetscCall(PEPSetProblemType(pep,PEP_HERMITIAN));
    107:     PetscCall(PetscOptionsBoolGroup("-pep_hyperbolic","Hyperbolic polynomial eigenvalue problem","PEPSetProblemType",&flg));
    108:     if (flg) PetscCall(PEPSetProblemType(pep,PEP_HYPERBOLIC));
    109:     PetscCall(PetscOptionsBoolGroupEnd("-pep_gyroscopic","Gyroscopic polynomial eigenvalue problem","PEPSetProblemType",&flg));
    110:     if (flg) PetscCall(PEPSetProblemType(pep,PEP_GYROSCOPIC));

    112:     scale = pep->scale;
    113:     PetscCall(PetscOptionsEnum("-pep_scale","Scaling strategy","PEPSetScale",PEPScaleTypes,(PetscEnum)scale,(PetscEnum*)&scale,&flg1));
    114:     r = pep->sfactor;
    115:     PetscCall(PetscOptionsReal("-pep_scale_factor","Scale factor","PEPSetScale",pep->sfactor,&r,&flg2));
    116:     if (!flg2 && r==1.0) r = PETSC_DEFAULT;
    117:     j = pep->sits;
    118:     PetscCall(PetscOptionsInt("-pep_scale_its","Number of iterations in diagonal scaling","PEPSetScale",pep->sits,&j,&flg3));
    119:     t = pep->slambda;
    120:     PetscCall(PetscOptionsReal("-pep_scale_lambda","Estimate of eigenvalue (modulus) for diagonal scaling","PEPSetScale",pep->slambda,&t,&flg4));
    121:     if (flg1 || flg2 || flg3 || flg4) PetscCall(PEPSetScale(pep,scale,r,NULL,NULL,j,t));

    123:     PetscCall(PetscOptionsEnum("-pep_extract","Extraction method","PEPSetExtract",PEPExtractTypes,(PetscEnum)pep->extract,(PetscEnum*)&pep->extract,NULL));

    125:     refine = pep->refine;
    126:     PetscCall(PetscOptionsEnum("-pep_refine","Iterative refinement method","PEPSetRefine",PEPRefineTypes,(PetscEnum)refine,(PetscEnum*)&refine,&flg1));
    127:     i = pep->npart;
    128:     PetscCall(PetscOptionsInt("-pep_refine_partitions","Number of partitions of the communicator for iterative refinement","PEPSetRefine",pep->npart,&i,&flg2));
    129:     r = pep->rtol;
    130:     PetscCall(PetscOptionsReal("-pep_refine_tol","Tolerance for iterative refinement","PEPSetRefine",pep->rtol==(PetscReal)PETSC_DEFAULT?SLEPC_DEFAULT_TOL/1000:pep->rtol,&r,&flg3));
    131:     j = pep->rits;
    132:     PetscCall(PetscOptionsInt("-pep_refine_its","Maximum number of iterations for iterative refinement","PEPSetRefine",pep->rits,&j,&flg4));
    133:     scheme = pep->scheme;
    134:     PetscCall(PetscOptionsEnum("-pep_refine_scheme","Scheme used for linear systems within iterative refinement","PEPSetRefine",PEPRefineSchemes,(PetscEnum)scheme,(PetscEnum*)&scheme,&flg5));
    135:     if (flg1 || flg2 || flg3 || flg4 || flg5) PetscCall(PEPSetRefine(pep,refine,i,r,j,scheme));

    137:     i = pep->max_it;
    138:     PetscCall(PetscOptionsInt("-pep_max_it","Maximum number of iterations","PEPSetTolerances",pep->max_it,&i,&flg1));
    139:     r = pep->tol;
    140:     PetscCall(PetscOptionsReal("-pep_tol","Tolerance","PEPSetTolerances",SlepcDefaultTol(pep->tol),&r,&flg2));
    141:     if (flg1 || flg2) PetscCall(PEPSetTolerances(pep,r,i));

    143:     PetscCall(PetscOptionsBoolGroupBegin("-pep_conv_rel","Relative error convergence test","PEPSetConvergenceTest",&flg));
    144:     if (flg) PetscCall(PEPSetConvergenceTest(pep,PEP_CONV_REL));
    145:     PetscCall(PetscOptionsBoolGroup("-pep_conv_norm","Convergence test relative to the matrix norms","PEPSetConvergenceTest",&flg));
    146:     if (flg) PetscCall(PEPSetConvergenceTest(pep,PEP_CONV_NORM));
    147:     PetscCall(PetscOptionsBoolGroup("-pep_conv_abs","Absolute error convergence test","PEPSetConvergenceTest",&flg));
    148:     if (flg) PetscCall(PEPSetConvergenceTest(pep,PEP_CONV_ABS));
    149:     PetscCall(PetscOptionsBoolGroupEnd("-pep_conv_user","User-defined convergence test","PEPSetConvergenceTest",&flg));
    150:     if (flg) PetscCall(PEPSetConvergenceTest(pep,PEP_CONV_USER));

    152:     PetscCall(PetscOptionsBoolGroupBegin("-pep_stop_basic","Stop iteration if all eigenvalues converged or max_it reached","PEPSetStoppingTest",&flg));
    153:     if (flg) PetscCall(PEPSetStoppingTest(pep,PEP_STOP_BASIC));
    154:     PetscCall(PetscOptionsBoolGroupEnd("-pep_stop_user","User-defined stopping test","PEPSetStoppingTest",&flg));
    155:     if (flg) PetscCall(PEPSetStoppingTest(pep,PEP_STOP_USER));

    157:     i = pep->nev;
    158:     PetscCall(PetscOptionsInt("-pep_nev","Number of eigenvalues to compute","PEPSetDimensions",pep->nev,&i,&flg1));
    159:     j = pep->ncv;
    160:     PetscCall(PetscOptionsInt("-pep_ncv","Number of basis vectors","PEPSetDimensions",pep->ncv,&j,&flg2));
    161:     k = pep->mpd;
    162:     PetscCall(PetscOptionsInt("-pep_mpd","Maximum dimension of projected problem","PEPSetDimensions",pep->mpd,&k,&flg3));
    163:     if (flg1 || flg2 || flg3) PetscCall(PEPSetDimensions(pep,i,j,k));

    165:     PetscCall(PetscOptionsEnum("-pep_basis","Polynomial basis","PEPSetBasis",PEPBasisTypes,(PetscEnum)pep->basis,(PetscEnum*)&pep->basis,NULL));

    167:     PetscCall(PetscOptionsBoolGroupBegin("-pep_largest_magnitude","Compute largest eigenvalues in magnitude","PEPSetWhichEigenpairs",&flg));
    168:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_LARGEST_MAGNITUDE));
    169:     PetscCall(PetscOptionsBoolGroup("-pep_smallest_magnitude","Compute smallest eigenvalues in magnitude","PEPSetWhichEigenpairs",&flg));
    170:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_SMALLEST_MAGNITUDE));
    171:     PetscCall(PetscOptionsBoolGroup("-pep_largest_real","Compute eigenvalues with largest real parts","PEPSetWhichEigenpairs",&flg));
    172:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_LARGEST_REAL));
    173:     PetscCall(PetscOptionsBoolGroup("-pep_smallest_real","Compute eigenvalues with smallest real parts","PEPSetWhichEigenpairs",&flg));
    174:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_SMALLEST_REAL));
    175:     PetscCall(PetscOptionsBoolGroup("-pep_largest_imaginary","Compute eigenvalues with largest imaginary parts","PEPSetWhichEigenpairs",&flg));
    176:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_LARGEST_IMAGINARY));
    177:     PetscCall(PetscOptionsBoolGroup("-pep_smallest_imaginary","Compute eigenvalues with smallest imaginary parts","PEPSetWhichEigenpairs",&flg));
    178:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_SMALLEST_IMAGINARY));
    179:     PetscCall(PetscOptionsBoolGroup("-pep_target_magnitude","Compute eigenvalues closest to target","PEPSetWhichEigenpairs",&flg));
    180:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_TARGET_MAGNITUDE));
    181:     PetscCall(PetscOptionsBoolGroup("-pep_target_real","Compute eigenvalues with real parts closest to target","PEPSetWhichEigenpairs",&flg));
    182:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_TARGET_REAL));
    183:     PetscCall(PetscOptionsBoolGroup("-pep_target_imaginary","Compute eigenvalues with imaginary parts closest to target","PEPSetWhichEigenpairs",&flg));
    184:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_TARGET_IMAGINARY));
    185:     PetscCall(PetscOptionsBoolGroupEnd("-pep_all","Compute all eigenvalues in an interval or a region","PEPSetWhichEigenpairs",&flg));
    186:     if (flg) PetscCall(PEPSetWhichEigenpairs(pep,PEP_ALL));

    188:     PetscCall(PetscOptionsScalar("-pep_target","Value of the target","PEPSetTarget",pep->target,&s,&flg));
    189:     if (flg) {
    190:       if (pep->which!=PEP_TARGET_REAL && pep->which!=PEP_TARGET_IMAGINARY) PetscCall(PEPSetWhichEigenpairs(pep,PEP_TARGET_MAGNITUDE));
    191:       PetscCall(PEPSetTarget(pep,s));
    192:     }

    194:     k = 2;
    195:     PetscCall(PetscOptionsRealArray("-pep_interval","Computational interval (two real values separated with a comma without spaces)","PEPSetInterval",array,&k,&flg));
    196:     if (flg) {
    197:       PetscCheck(k>1,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_SIZ,"Must pass two values in -pep_interval (comma-separated without spaces)");
    198:       PetscCall(PEPSetWhichEigenpairs(pep,PEP_ALL));
    199:       PetscCall(PEPSetInterval(pep,array[0],array[1]));
    200:     }

    202:     /* -----------------------------------------------------------------------*/
    203:     /*
    204:       Cancels all monitors hardwired into code before call to PEPSetFromOptions()
    205:     */
    206:     PetscCall(PetscOptionsBool("-pep_monitor_cancel","Remove any hardwired monitor routines","PEPMonitorCancel",PETSC_FALSE,&flg,&set));
    207:     if (set && flg) PetscCall(PEPMonitorCancel(pep));
    208:     PetscCall(PEPMonitorSetFromOptions(pep,"-pep_monitor","first_approximation",NULL,PETSC_FALSE));
    209:     PetscCall(PEPMonitorSetFromOptions(pep,"-pep_monitor_all","all_approximations",NULL,PETSC_TRUE));
    210:     PetscCall(PEPMonitorSetFromOptions(pep,"-pep_monitor_conv","convergence_history",NULL,PETSC_FALSE));

    212:     /* -----------------------------------------------------------------------*/
    213:     PetscCall(PetscOptionsName("-pep_view","Print detailed information on solver used","PEPView",NULL));
    214:     PetscCall(PetscOptionsName("-pep_view_vectors","View computed eigenvectors","PEPVectorsView",NULL));
    215:     PetscCall(PetscOptionsName("-pep_view_values","View computed eigenvalues","PEPValuesView",NULL));
    216:     PetscCall(PetscOptionsName("-pep_converged_reason","Print reason for convergence, and number of iterations","PEPConvergedReasonView",NULL));
    217:     PetscCall(PetscOptionsName("-pep_error_absolute","Print absolute errors of each eigenpair","PEPErrorView",NULL));
    218:     PetscCall(PetscOptionsName("-pep_error_relative","Print relative errors of each eigenpair","PEPErrorView",NULL));
    219:     PetscCall(PetscOptionsName("-pep_error_backward","Print backward errors of each eigenpair","PEPErrorView",NULL));

    221:     PetscTryTypeMethod(pep,setfromoptions,PetscOptionsObject);
    222:     PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)pep,PetscOptionsObject));
    223:   PetscOptionsEnd();

    225:   if (!pep->V) PetscCall(PEPGetBV(pep,&pep->V));
    226:   PetscCall(BVSetFromOptions(pep->V));
    227:   if (!pep->rg) PetscCall(PEPGetRG(pep,&pep->rg));
    228:   PetscCall(RGSetFromOptions(pep->rg));
    229:   if (!pep->ds) PetscCall(PEPGetDS(pep,&pep->ds));
    230:   PetscCall(PEPSetDSType(pep));
    231:   PetscCall(DSSetFromOptions(pep->ds));
    232:   if (!pep->st) PetscCall(PEPGetST(pep,&pep->st));
    233:   PetscCall(PEPSetDefaultST(pep));
    234:   PetscCall(STSetFromOptions(pep->st));
    235:   if (!pep->refineksp) PetscCall(PEPRefineGetKSP(pep,&pep->refineksp));
    236:   PetscCall(KSPSetFromOptions(pep->refineksp));
    237:   PetscFunctionReturn(PETSC_SUCCESS);
    238: }

    240: /*@C
    241:    PEPGetTolerances - Gets the tolerance and maximum iteration count used
    242:    by the PEP convergence tests.

    244:    Not Collective

    246:    Input Parameter:
    247: .  pep - the polynomial eigensolver context

    249:    Output Parameters:
    250: +  tol - the convergence tolerance
    251: -  maxits - maximum number of iterations

    253:    Notes:
    254:    The user can specify NULL for any parameter that is not needed.

    256:    Level: intermediate

    258: .seealso: PEPSetTolerances()
    259: @*/
    260: PetscErrorCode PEPGetTolerances(PEP pep,PetscReal *tol,PetscInt *maxits)
    261: {
    262:   PetscFunctionBegin;
    264:   if (tol)    *tol    = pep->tol;
    265:   if (maxits) *maxits = pep->max_it;
    266:   PetscFunctionReturn(PETSC_SUCCESS);
    267: }

    269: /*@
    270:    PEPSetTolerances - Sets the tolerance and maximum iteration count used
    271:    by the PEP convergence tests.

    273:    Logically Collective

    275:    Input Parameters:
    276: +  pep - the polynomial eigensolver context
    277: .  tol - the convergence tolerance
    278: -  maxits - maximum number of iterations to use

    280:    Options Database Keys:
    281: +  -pep_tol <tol> - Sets the convergence tolerance
    282: -  -pep_max_it <maxits> - Sets the maximum number of iterations allowed

    284:    Notes:
    285:    Use PETSC_DEFAULT for either argument to assign a reasonably good value.

    287:    Level: intermediate

    289: .seealso: PEPGetTolerances()
    290: @*/
    291: PetscErrorCode PEPSetTolerances(PEP pep,PetscReal tol,PetscInt maxits)
    292: {
    293:   PetscFunctionBegin;
    297:   if (tol == (PetscReal)PETSC_DEFAULT) {
    298:     pep->tol   = PETSC_DEFAULT;
    299:     pep->state = PEP_STATE_INITIAL;
    300:   } else {
    301:     PetscCheck(tol>0.0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of tol. Must be > 0");
    302:     pep->tol = tol;
    303:   }
    304:   if (maxits == PETSC_DEFAULT || maxits == PETSC_DECIDE) {
    305:     pep->max_it = PETSC_DEFAULT;
    306:     pep->state  = PEP_STATE_INITIAL;
    307:   } else {
    308:     PetscCheck(maxits>0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of maxits. Must be > 0");
    309:     pep->max_it = maxits;
    310:   }
    311:   PetscFunctionReturn(PETSC_SUCCESS);
    312: }

    314: /*@C
    315:    PEPGetDimensions - Gets the number of eigenvalues to compute
    316:    and the dimension of the subspace.

    318:    Not Collective

    320:    Input Parameter:
    321: .  pep - the polynomial eigensolver context

    323:    Output Parameters:
    324: +  nev - number of eigenvalues to compute
    325: .  ncv - the maximum dimension of the subspace to be used by the solver
    326: -  mpd - the maximum dimension allowed for the projected problem

    328:    Notes:
    329:    The user can specify NULL for any parameter that is not needed.

    331:    Level: intermediate

    333: .seealso: PEPSetDimensions()
    334: @*/
    335: PetscErrorCode PEPGetDimensions(PEP pep,PetscInt *nev,PetscInt *ncv,PetscInt *mpd)
    336: {
    337:   PetscFunctionBegin;
    339:   if (nev) *nev = pep->nev;
    340:   if (ncv) *ncv = pep->ncv;
    341:   if (mpd) *mpd = pep->mpd;
    342:   PetscFunctionReturn(PETSC_SUCCESS);
    343: }

    345: /*@
    346:    PEPSetDimensions - Sets the number of eigenvalues to compute
    347:    and the dimension of the subspace.

    349:    Logically Collective

    351:    Input Parameters:
    352: +  pep - the polynomial eigensolver context
    353: .  nev - number of eigenvalues to compute
    354: .  ncv - the maximum dimension of the subspace to be used by the solver
    355: -  mpd - the maximum dimension allowed for the projected problem

    357:    Options Database Keys:
    358: +  -pep_nev <nev> - Sets the number of eigenvalues
    359: .  -pep_ncv <ncv> - Sets the dimension of the subspace
    360: -  -pep_mpd <mpd> - Sets the maximum projected dimension

    362:    Notes:
    363:    Use PETSC_DEFAULT for ncv and mpd to assign a reasonably good value, which is
    364:    dependent on the solution method.

    366:    The parameters ncv and mpd are intimately related, so that the user is advised
    367:    to set one of them at most. Normal usage is that
    368:    (a) in cases where nev is small, the user sets ncv (a reasonable default is 2*nev); and
    369:    (b) in cases where nev is large, the user sets mpd.

    371:    The value of ncv should always be between nev and (nev+mpd), typically
    372:    ncv=nev+mpd. If nev is not too large, mpd=nev is a reasonable choice, otherwise
    373:    a smaller value should be used.

    375:    When computing all eigenvalues in an interval, see PEPSetInterval(), these
    376:    parameters lose relevance, and tuning must be done with PEPSTOARSetDimensions().

    378:    Level: intermediate

    380: .seealso: PEPGetDimensions(), PEPSetInterval(), PEPSTOARSetDimensions()
    381: @*/
    382: PetscErrorCode PEPSetDimensions(PEP pep,PetscInt nev,PetscInt ncv,PetscInt mpd)
    383: {
    384:   PetscFunctionBegin;
    389:   PetscCheck(nev>0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of nev. Must be > 0");
    390:   pep->nev = nev;
    391:   if (ncv == PETSC_DECIDE || ncv == PETSC_DEFAULT) {
    392:     pep->ncv = PETSC_DEFAULT;
    393:   } else {
    394:     PetscCheck(ncv>0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of ncv. Must be > 0");
    395:     pep->ncv = ncv;
    396:   }
    397:   if (mpd == PETSC_DECIDE || mpd == PETSC_DEFAULT) {
    398:     pep->mpd = PETSC_DEFAULT;
    399:   } else {
    400:     PetscCheck(mpd>0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of mpd. Must be > 0");
    401:     pep->mpd = mpd;
    402:   }
    403:   pep->state = PEP_STATE_INITIAL;
    404:   PetscFunctionReturn(PETSC_SUCCESS);
    405: }

    407: /*@
    408:    PEPSetWhichEigenpairs - Specifies which portion of the spectrum is
    409:    to be sought.

    411:    Logically Collective

    413:    Input Parameters:
    414: +  pep   - eigensolver context obtained from PEPCreate()
    415: -  which - the portion of the spectrum to be sought

    417:    Options Database Keys:
    418: +   -pep_largest_magnitude - Sets largest eigenvalues in magnitude
    419: .   -pep_smallest_magnitude - Sets smallest eigenvalues in magnitude
    420: .   -pep_largest_real - Sets largest real parts
    421: .   -pep_smallest_real - Sets smallest real parts
    422: .   -pep_largest_imaginary - Sets largest imaginary parts
    423: .   -pep_smallest_imaginary - Sets smallest imaginary parts
    424: .   -pep_target_magnitude - Sets eigenvalues closest to target
    425: .   -pep_target_real - Sets real parts closest to target
    426: .   -pep_target_imaginary - Sets imaginary parts closest to target
    427: -   -pep_all - Sets all eigenvalues in an interval or region

    429:    Notes:
    430:    The parameter 'which' can have one of these values

    432: +     PEP_LARGEST_MAGNITUDE - largest eigenvalues in magnitude (default)
    433: .     PEP_SMALLEST_MAGNITUDE - smallest eigenvalues in magnitude
    434: .     PEP_LARGEST_REAL - largest real parts
    435: .     PEP_SMALLEST_REAL - smallest real parts
    436: .     PEP_LARGEST_IMAGINARY - largest imaginary parts
    437: .     PEP_SMALLEST_IMAGINARY - smallest imaginary parts
    438: .     PEP_TARGET_MAGNITUDE - eigenvalues closest to the target (in magnitude)
    439: .     PEP_TARGET_REAL - eigenvalues with real part closest to target
    440: .     PEP_TARGET_IMAGINARY - eigenvalues with imaginary part closest to target
    441: .     PEP_ALL - all eigenvalues contained in a given interval or region
    442: -     PEP_WHICH_USER - user defined ordering set with PEPSetEigenvalueComparison()

    444:    Not all eigensolvers implemented in PEP account for all the possible values
    445:    stated above. If SLEPc is compiled for real numbers PEP_LARGEST_IMAGINARY
    446:    and PEP_SMALLEST_IMAGINARY use the absolute value of the imaginary part
    447:    for eigenvalue selection.

    449:    The target is a scalar value provided with PEPSetTarget().

    451:    The criterion PEP_TARGET_IMAGINARY is available only in case PETSc and
    452:    SLEPc have been built with complex scalars.

    454:    PEP_ALL is intended for use in combination with an interval (see
    455:    PEPSetInterval()), when all eigenvalues within the interval are requested,
    456:    and also for computing all eigenvalues in a region with the CISS solver.
    457:    In both cases, the number of eigenvalues is unknown, so the nev parameter
    458:    has a different sense, see PEPSetDimensions().

    460:    Level: intermediate

    462: .seealso: PEPGetWhichEigenpairs(), PEPSetTarget(), PEPSetInterval(),
    463:           PEPSetDimensions(), PEPSetEigenvalueComparison(), PEPWhich
    464: @*/
    465: PetscErrorCode PEPSetWhichEigenpairs(PEP pep,PEPWhich which)
    466: {
    467:   PetscFunctionBegin;
    470:   switch (which) {
    471:     case PEP_LARGEST_MAGNITUDE:
    472:     case PEP_SMALLEST_MAGNITUDE:
    473:     case PEP_LARGEST_REAL:
    474:     case PEP_SMALLEST_REAL:
    475:     case PEP_LARGEST_IMAGINARY:
    476:     case PEP_SMALLEST_IMAGINARY:
    477:     case PEP_TARGET_MAGNITUDE:
    478:     case PEP_TARGET_REAL:
    479: #if defined(PETSC_USE_COMPLEX)
    480:     case PEP_TARGET_IMAGINARY:
    481: #endif
    482:     case PEP_ALL:
    483:     case PEP_WHICH_USER:
    484:       if (pep->which != which) {
    485:         pep->state = PEP_STATE_INITIAL;
    486:         pep->which = which;
    487:       }
    488:       break;
    489: #if !defined(PETSC_USE_COMPLEX)
    490:     case PEP_TARGET_IMAGINARY:
    491:       SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_SUP,"PEP_TARGET_IMAGINARY can be used only with complex scalars");
    492: #endif
    493:     default:
    494:       SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'which' value");
    495:   }
    496:   PetscFunctionReturn(PETSC_SUCCESS);
    497: }

    499: /*@
    500:     PEPGetWhichEigenpairs - Returns which portion of the spectrum is to be
    501:     sought.

    503:     Not Collective

    505:     Input Parameter:
    506: .   pep - eigensolver context obtained from PEPCreate()

    508:     Output Parameter:
    509: .   which - the portion of the spectrum to be sought

    511:     Notes:
    512:     See PEPSetWhichEigenpairs() for possible values of 'which'.

    514:     Level: intermediate

    516: .seealso: PEPSetWhichEigenpairs(), PEPWhich
    517: @*/
    518: PetscErrorCode PEPGetWhichEigenpairs(PEP pep,PEPWhich *which)
    519: {
    520:   PetscFunctionBegin;
    523:   *which = pep->which;
    524:   PetscFunctionReturn(PETSC_SUCCESS);
    525: }

    527: /*@C
    528:    PEPSetEigenvalueComparison - Specifies the eigenvalue comparison function
    529:    when PEPSetWhichEigenpairs() is set to PEP_WHICH_USER.

    531:    Logically Collective

    533:    Input Parameters:
    534: +  pep  - eigensolver context obtained from PEPCreate()
    535: .  comp - a pointer to the comparison function
    536: -  ctx  - a context pointer (the last parameter to the comparison function)

    538:    Calling sequence of comp:
    539: $  PetscErrorCode comp(PetscScalar ar,PetscScalar ai,PetscScalar br,PetscScalar bi,PetscInt *res,void *ctx)
    540: +   ar     - real part of the 1st eigenvalue
    541: .   ai     - imaginary part of the 1st eigenvalue
    542: .   br     - real part of the 2nd eigenvalue
    543: .   bi     - imaginary part of the 2nd eigenvalue
    544: .   res    - result of comparison
    545: -   ctx    - optional context, as set by PEPSetEigenvalueComparison()

    547:    Note:
    548:    The returning parameter 'res' can be
    549: +  negative - if the 1st eigenvalue is preferred to the 2st one
    550: .  zero     - if both eigenvalues are equally preferred
    551: -  positive - if the 2st eigenvalue is preferred to the 1st one

    553:    Level: advanced

    555: .seealso: PEPSetWhichEigenpairs(), PEPWhich
    556: @*/
    557: PetscErrorCode PEPSetEigenvalueComparison(PEP pep,PetscErrorCode (*comp)(PetscScalar ar,PetscScalar ai,PetscScalar br,PetscScalar bi,PetscInt *res,void *ctx),void* ctx)
    558: {
    559:   PetscFunctionBegin;
    561:   pep->sc->comparison    = comp;
    562:   pep->sc->comparisonctx = ctx;
    563:   pep->which             = PEP_WHICH_USER;
    564:   PetscFunctionReturn(PETSC_SUCCESS);
    565: }

    567: /*@
    568:    PEPSetProblemType - Specifies the type of the polynomial eigenvalue problem.

    570:    Logically Collective

    572:    Input Parameters:
    573: +  pep  - the polynomial eigensolver context
    574: -  type - a known type of polynomial eigenvalue problem

    576:    Options Database Keys:
    577: +  -pep_general - general problem with no particular structure
    578: .  -pep_hermitian - problem whose coefficient matrices are Hermitian
    579: .  -pep_hyperbolic - Hermitian problem that satisfies the definition of hyperbolic
    580: -  -pep_gyroscopic - problem with Hamiltonian structure

    582:    Notes:
    583:    Allowed values for the problem type are general (PEP_GENERAL), Hermitian
    584:    (PEP_HERMITIAN), hyperbolic (PEP_HYPERBOLIC), and gyroscopic (PEP_GYROSCOPIC).

    586:    This function is used to instruct SLEPc to exploit certain structure in
    587:    the polynomial eigenproblem. By default, no particular structure is assumed.

    589:    If the problem matrices are Hermitian (symmetric in the real case) or
    590:    Hermitian/skew-Hermitian then the solver can exploit this fact to perform
    591:    less operations or provide better stability. Hyperbolic problems are a
    592:    particular case of Hermitian problems, some solvers may treat them simply as
    593:    Hermitian.

    595:    Level: intermediate

    597: .seealso: PEPSetOperators(), PEPSetType(), PEPGetProblemType(), PEPProblemType
    598: @*/
    599: PetscErrorCode PEPSetProblemType(PEP pep,PEPProblemType type)
    600: {
    601:   PetscFunctionBegin;
    604:   PetscCheck(type==PEP_GENERAL || type==PEP_HERMITIAN || type==PEP_HYPERBOLIC || type==PEP_GYROSCOPIC,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_WRONG,"Unknown eigenvalue problem type");
    605:   if (type != pep->problem_type) {
    606:     pep->problem_type = type;
    607:     pep->state = PEP_STATE_INITIAL;
    608:   }
    609:   PetscFunctionReturn(PETSC_SUCCESS);
    610: }

    612: /*@
    613:    PEPGetProblemType - Gets the problem type from the PEP object.

    615:    Not Collective

    617:    Input Parameter:
    618: .  pep - the polynomial eigensolver context

    620:    Output Parameter:
    621: .  type - the problem type

    623:    Level: intermediate

    625: .seealso: PEPSetProblemType(), PEPProblemType
    626: @*/
    627: PetscErrorCode PEPGetProblemType(PEP pep,PEPProblemType *type)
    628: {
    629:   PetscFunctionBegin;
    632:   *type = pep->problem_type;
    633:   PetscFunctionReturn(PETSC_SUCCESS);
    634: }

    636: /*@
    637:    PEPSetBasis - Specifies the type of polynomial basis used to describe the
    638:    polynomial eigenvalue problem.

    640:    Logically Collective

    642:    Input Parameters:
    643: +  pep   - the polynomial eigensolver context
    644: -  basis - the type of polynomial basis

    646:    Options Database Key:
    647: .  -pep_basis <basis> - Select the basis type

    649:    Notes:
    650:    By default, the coefficient matrices passed via PEPSetOperators() are
    651:    expressed in the monomial basis, i.e.
    652:    P(lambda) = A_0 + lambda*A_1 + lambda^2*A_2 + ... + lambda^d*A_d.
    653:    Other polynomial bases may have better numerical behaviour, but the user
    654:    must then pass the coefficient matrices accordingly.

    656:    Level: intermediate

    658: .seealso: PEPSetOperators(), PEPGetBasis(), PEPBasis
    659: @*/
    660: PetscErrorCode PEPSetBasis(PEP pep,PEPBasis basis)
    661: {
    662:   PetscFunctionBegin;
    665:   pep->basis = basis;
    666:   PetscFunctionReturn(PETSC_SUCCESS);
    667: }

    669: /*@
    670:    PEPGetBasis - Gets the type of polynomial basis from the PEP object.

    672:    Not Collective

    674:    Input Parameter:
    675: .  pep - the polynomial eigensolver context

    677:    Output Parameter:
    678: .  basis - the polynomial basis

    680:    Level: intermediate

    682: .seealso: PEPSetBasis(), PEPBasis
    683: @*/
    684: PetscErrorCode PEPGetBasis(PEP pep,PEPBasis *basis)
    685: {
    686:   PetscFunctionBegin;
    689:   *basis = pep->basis;
    690:   PetscFunctionReturn(PETSC_SUCCESS);
    691: }

    693: /*@
    694:    PEPSetTrackAll - Specifies if the solver must compute the residual of all
    695:    approximate eigenpairs or not.

    697:    Logically Collective

    699:    Input Parameters:
    700: +  pep      - the eigensolver context
    701: -  trackall - whether compute all residuals or not

    703:    Notes:
    704:    If the user sets trackall=PETSC_TRUE then the solver explicitly computes
    705:    the residual for each eigenpair approximation. Computing the residual is
    706:    usually an expensive operation and solvers commonly compute the associated
    707:    residual to the first unconverged eigenpair.

    709:    The option '-pep_monitor_all' automatically activates this option.

    711:    Level: developer

    713: .seealso: PEPGetTrackAll()
    714: @*/
    715: PetscErrorCode PEPSetTrackAll(PEP pep,PetscBool trackall)
    716: {
    717:   PetscFunctionBegin;
    720:   pep->trackall = trackall;
    721:   PetscFunctionReturn(PETSC_SUCCESS);
    722: }

    724: /*@
    725:    PEPGetTrackAll - Returns the flag indicating whether all residual norms must
    726:    be computed or not.

    728:    Not Collective

    730:    Input Parameter:
    731: .  pep - the eigensolver context

    733:    Output Parameter:
    734: .  trackall - the returned flag

    736:    Level: developer

    738: .seealso: PEPSetTrackAll()
    739: @*/
    740: PetscErrorCode PEPGetTrackAll(PEP pep,PetscBool *trackall)
    741: {
    742:   PetscFunctionBegin;
    745:   *trackall = pep->trackall;
    746:   PetscFunctionReturn(PETSC_SUCCESS);
    747: }

    749: /*@C
    750:    PEPSetConvergenceTestFunction - Sets a function to compute the error estimate
    751:    used in the convergence test.

    753:    Logically Collective

    755:    Input Parameters:
    756: +  pep     - eigensolver context obtained from PEPCreate()
    757: .  conv    - a pointer to the convergence test function
    758: .  ctx     - context for private data for the convergence routine (may be null)
    759: -  destroy - a routine for destroying the context (may be null)

    761:    Calling sequence of conv:
    762: $  PetscErrorCode conv(PEP pep,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)
    763: +   pep    - eigensolver context obtained from PEPCreate()
    764: .   eigr   - real part of the eigenvalue
    765: .   eigi   - imaginary part of the eigenvalue
    766: .   res    - residual norm associated to the eigenpair
    767: .   errest - (output) computed error estimate
    768: -   ctx    - optional context, as set by PEPSetConvergenceTestFunction()

    770:    Note:
    771:    If the error estimate returned by the convergence test function is less than
    772:    the tolerance, then the eigenvalue is accepted as converged.

    774:    Level: advanced

    776: .seealso: PEPSetConvergenceTest(), PEPSetTolerances()
    777: @*/
    778: PetscErrorCode PEPSetConvergenceTestFunction(PEP pep,PetscErrorCode (*conv)(PEP pep,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx),void* ctx,PetscErrorCode (*destroy)(void*))
    779: {
    780:   PetscFunctionBegin;
    782:   if (pep->convergeddestroy) PetscCall((*pep->convergeddestroy)(pep->convergedctx));
    783:   pep->convergeduser    = conv;
    784:   pep->convergeddestroy = destroy;
    785:   pep->convergedctx     = ctx;
    786:   if (conv == PEPConvergedRelative) pep->conv = PEP_CONV_REL;
    787:   else if (conv == PEPConvergedNorm) pep->conv = PEP_CONV_NORM;
    788:   else if (conv == PEPConvergedAbsolute) pep->conv = PEP_CONV_ABS;
    789:   else {
    790:     pep->conv      = PEP_CONV_USER;
    791:     pep->converged = pep->convergeduser;
    792:   }
    793:   PetscFunctionReturn(PETSC_SUCCESS);
    794: }

    796: /*@
    797:    PEPSetConvergenceTest - Specifies how to compute the error estimate
    798:    used in the convergence test.

    800:    Logically Collective

    802:    Input Parameters:
    803: +  pep  - eigensolver context obtained from PEPCreate()
    804: -  conv - the type of convergence test

    806:    Options Database Keys:
    807: +  -pep_conv_abs    - Sets the absolute convergence test
    808: .  -pep_conv_rel    - Sets the convergence test relative to the eigenvalue
    809: .  -pep_conv_norm   - Sets the convergence test relative to the matrix norms
    810: -  -pep_conv_user   - Selects the user-defined convergence test

    812:    Note:
    813:    The parameter 'conv' can have one of these values
    814: +     PEP_CONV_ABS    - absolute error ||r||
    815: .     PEP_CONV_REL    - error relative to the eigenvalue l, ||r||/|l|
    816: .     PEP_CONV_NORM   - error relative matrix norms, ||r||/sum_i(l^i*||A_i||)
    817: -     PEP_CONV_USER   - function set by PEPSetConvergenceTestFunction()

    819:    Level: intermediate

    821: .seealso: PEPGetConvergenceTest(), PEPSetConvergenceTestFunction(), PEPSetStoppingTest(), PEPConv
    822: @*/
    823: PetscErrorCode PEPSetConvergenceTest(PEP pep,PEPConv conv)
    824: {
    825:   PetscFunctionBegin;
    828:   switch (conv) {
    829:     case PEP_CONV_ABS:  pep->converged = PEPConvergedAbsolute; break;
    830:     case PEP_CONV_REL:  pep->converged = PEPConvergedRelative; break;
    831:     case PEP_CONV_NORM: pep->converged = PEPConvergedNorm; break;
    832:     case PEP_CONV_USER:
    833:       PetscCheck(pep->convergeduser,PetscObjectComm((PetscObject)pep),PETSC_ERR_ORDER,"Must call PEPSetConvergenceTestFunction() first");
    834:       pep->converged = pep->convergeduser;
    835:       break;
    836:     default:
    837:       SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'conv' value");
    838:   }
    839:   pep->conv = conv;
    840:   PetscFunctionReturn(PETSC_SUCCESS);
    841: }

    843: /*@
    844:    PEPGetConvergenceTest - Gets the method used to compute the error estimate
    845:    used in the convergence test.

    847:    Not Collective

    849:    Input Parameters:
    850: .  pep   - eigensolver context obtained from PEPCreate()

    852:    Output Parameters:
    853: .  conv  - the type of convergence test

    855:    Level: intermediate

    857: .seealso: PEPSetConvergenceTest(), PEPConv
    858: @*/
    859: PetscErrorCode PEPGetConvergenceTest(PEP pep,PEPConv *conv)
    860: {
    861:   PetscFunctionBegin;
    864:   *conv = pep->conv;
    865:   PetscFunctionReturn(PETSC_SUCCESS);
    866: }

    868: /*@C
    869:    PEPSetStoppingTestFunction - Sets a function to decide when to stop the outer
    870:    iteration of the eigensolver.

    872:    Logically Collective

    874:    Input Parameters:
    875: +  pep     - eigensolver context obtained from PEPCreate()
    876: .  stop    - pointer to the stopping test function
    877: .  ctx     - context for private data for the stopping routine (may be null)
    878: -  destroy - a routine for destroying the context (may be null)

    880:    Calling sequence of stop:
    881: $  PetscErrorCode stop(PEP pep,PetscInt its,PetscInt max_it,PetscInt nconv,PetscInt nev,PEPConvergedReason *reason,void *ctx)
    882: +   pep    - eigensolver context obtained from PEPCreate()
    883: .   its    - current number of iterations
    884: .   max_it - maximum number of iterations
    885: .   nconv  - number of currently converged eigenpairs
    886: .   nev    - number of requested eigenpairs
    887: .   reason - (output) result of the stopping test
    888: -   ctx    - optional context, as set by PEPSetStoppingTestFunction()

    890:    Note:
    891:    Normal usage is to first call the default routine PEPStoppingBasic() and then
    892:    set reason to PEP_CONVERGED_USER if some user-defined conditions have been
    893:    met. To let the eigensolver continue iterating, the result must be left as
    894:    PEP_CONVERGED_ITERATING.

    896:    Level: advanced

    898: .seealso: PEPSetStoppingTest(), PEPStoppingBasic()
    899: @*/
    900: PetscErrorCode PEPSetStoppingTestFunction(PEP pep,PetscErrorCode (*stop)(PEP pep,PetscInt its,PetscInt max_it,PetscInt nconv,PetscInt nev,PEPConvergedReason *reason,void *ctx),void* ctx,PetscErrorCode (*destroy)(void*))
    901: {
    902:   PetscFunctionBegin;
    904:   if (pep->stoppingdestroy) PetscCall((*pep->stoppingdestroy)(pep->stoppingctx));
    905:   pep->stoppinguser    = stop;
    906:   pep->stoppingdestroy = destroy;
    907:   pep->stoppingctx     = ctx;
    908:   if (stop == PEPStoppingBasic) pep->stop = PEP_STOP_BASIC;
    909:   else {
    910:     pep->stop     = PEP_STOP_USER;
    911:     pep->stopping = pep->stoppinguser;
    912:   }
    913:   PetscFunctionReturn(PETSC_SUCCESS);
    914: }

    916: /*@
    917:    PEPSetStoppingTest - Specifies how to decide the termination of the outer
    918:    loop of the eigensolver.

    920:    Logically Collective

    922:    Input Parameters:
    923: +  pep  - eigensolver context obtained from PEPCreate()
    924: -  stop - the type of stopping test

    926:    Options Database Keys:
    927: +  -pep_stop_basic - Sets the default stopping test
    928: -  -pep_stop_user  - Selects the user-defined stopping test

    930:    Note:
    931:    The parameter 'stop' can have one of these values
    932: +     PEP_STOP_BASIC - default stopping test
    933: -     PEP_STOP_USER  - function set by PEPSetStoppingTestFunction()

    935:    Level: advanced

    937: .seealso: PEPGetStoppingTest(), PEPSetStoppingTestFunction(), PEPSetConvergenceTest(), PEPStop
    938: @*/
    939: PetscErrorCode PEPSetStoppingTest(PEP pep,PEPStop stop)
    940: {
    941:   PetscFunctionBegin;
    944:   switch (stop) {
    945:     case PEP_STOP_BASIC: pep->stopping = PEPStoppingBasic; break;
    946:     case PEP_STOP_USER:
    947:       PetscCheck(pep->stoppinguser,PetscObjectComm((PetscObject)pep),PETSC_ERR_ORDER,"Must call PEPSetStoppingTestFunction() first");
    948:       pep->stopping = pep->stoppinguser;
    949:       break;
    950:     default:
    951:       SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'stop' value");
    952:   }
    953:   pep->stop = stop;
    954:   PetscFunctionReturn(PETSC_SUCCESS);
    955: }

    957: /*@
    958:    PEPGetStoppingTest - Gets the method used to decide the termination of the outer
    959:    loop of the eigensolver.

    961:    Not Collective

    963:    Input Parameters:
    964: .  pep   - eigensolver context obtained from PEPCreate()

    966:    Output Parameters:
    967: .  stop  - the type of stopping test

    969:    Level: advanced

    971: .seealso: PEPSetStoppingTest(), PEPStop
    972: @*/
    973: PetscErrorCode PEPGetStoppingTest(PEP pep,PEPStop *stop)
    974: {
    975:   PetscFunctionBegin;
    978:   *stop = pep->stop;
    979:   PetscFunctionReturn(PETSC_SUCCESS);
    980: }

    982: /*@
    983:    PEPSetScale - Specifies the scaling strategy to be used.

    985:    Collective

    987:    Input Parameters:
    988: +  pep    - the eigensolver context
    989: .  scale  - scaling strategy
    990: .  alpha  - the scaling factor used in the scalar strategy
    991: .  Dl     - the left diagonal matrix of the diagonal scaling algorithm
    992: .  Dr     - the right diagonal matrix of the diagonal scaling algorithm
    993: .  its    - number of iterations of the diagonal scaling algorithm
    994: -  lambda - approximation to wanted eigenvalues (modulus)

    996:    Options Database Keys:
    997: +  -pep_scale <type> - scaling type, one of <none,scalar,diagonal,both>
    998: .  -pep_scale_factor <alpha> - the scaling factor
    999: .  -pep_scale_its <its> - number of iterations
    1000: -  -pep_scale_lambda <lambda> - approximation to eigenvalues

    1002:    Notes:
    1003:    There are two non-exclusive scaling strategies, scalar and diagonal.

    1005:    In the scalar strategy, scaling is applied to the eigenvalue, that is,
    1006:    mu = lambda/alpha is the new eigenvalue and all matrices are scaled
    1007:    accordingly. After solving the scaled problem, the original lambda is
    1008:    recovered. Parameter 'alpha' must be positive. Use PETSC_DEFAULT to let
    1009:    the solver compute a reasonable scaling factor.

    1011:    In the diagonal strategy, the solver works implicitly with matrix Dl*A*Dr,
    1012:    where Dl and Dr are appropriate diagonal matrices. This improves the accuracy
    1013:    of the computed results in some cases. The user may provide the Dr and Dl
    1014:    matrices represented as Vec objects storing diagonal elements. If not
    1015:    provided, these matrices are computed internally. This option requires
    1016:    that the polynomial coefficient matrices are of MATAIJ type.
    1017:    The parameter 'its' is the number of iterations performed by the method.
    1018:    Parameter 'lambda' must be positive. Use PETSC_DEFAULT or set lambda = 1.0 if
    1019:    no information about eigenvalues is available.

    1021:    Level: intermediate

    1023: .seealso: PEPGetScale()
    1024: @*/
    1025: PetscErrorCode PEPSetScale(PEP pep,PEPScale scale,PetscReal alpha,Vec Dl,Vec Dr,PetscInt its,PetscReal lambda)
    1026: {
    1027:   PetscFunctionBegin;
    1030:   pep->scale = scale;
    1031:   if (scale==PEP_SCALE_SCALAR || scale==PEP_SCALE_BOTH) {
    1033:     if (alpha == (PetscReal)PETSC_DEFAULT || alpha == (PetscReal)PETSC_DECIDE) {
    1034:       pep->sfactor = 0.0;
    1035:       pep->sfactor_set = PETSC_FALSE;
    1036:     } else {
    1037:       PetscCheck(alpha>0.0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of alpha. Must be > 0");
    1038:       pep->sfactor = alpha;
    1039:       pep->sfactor_set = PETSC_TRUE;
    1040:     }
    1041:   }
    1042:   if (scale==PEP_SCALE_DIAGONAL || scale==PEP_SCALE_BOTH) {
    1043:     if (Dl) {
    1045:       PetscCheckSameComm(pep,1,Dl,4);
    1046:       PetscCall(PetscObjectReference((PetscObject)Dl));
    1047:       PetscCall(VecDestroy(&pep->Dl));
    1048:       pep->Dl = Dl;
    1049:     }
    1050:     if (Dr) {
    1052:       PetscCheckSameComm(pep,1,Dr,5);
    1053:       PetscCall(PetscObjectReference((PetscObject)Dr));
    1054:       PetscCall(VecDestroy(&pep->Dr));
    1055:       pep->Dr = Dr;
    1056:     }
    1059:     if (its==PETSC_DECIDE || its==PETSC_DEFAULT) pep->sits = 5;
    1060:     else pep->sits = its;
    1061:     if (lambda == (PetscReal)PETSC_DECIDE || lambda == (PetscReal)PETSC_DEFAULT) pep->slambda = 1.0;
    1062:     else {
    1063:       PetscCheck(lambda>0.0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of lambda. Must be > 0");
    1064:       pep->slambda = lambda;
    1065:     }
    1066:   }
    1067:   pep->state = PEP_STATE_INITIAL;
    1068:   PetscFunctionReturn(PETSC_SUCCESS);
    1069: }

    1071: /*@C
    1072:    PEPGetScale - Gets the scaling strategy used by the PEP object, and the
    1073:    associated parameters.

    1075:    Not Collective

    1077:    Input Parameter:
    1078: .  pep - the eigensolver context

    1080:    Output Parameters:
    1081: +  scale  - scaling strategy
    1082: .  alpha  - the scaling factor used in the scalar strategy
    1083: .  Dl     - the left diagonal matrix of the diagonal scaling algorithm
    1084: .  Dr     - the right diagonal matrix of the diagonal scaling algorithm
    1085: .  its    - number of iterations of the diagonal scaling algorithm
    1086: -  lambda - approximation to wanted eigenvalues (modulus)

    1088:    Level: intermediate

    1090:    Note:
    1091:    The user can specify NULL for any parameter that is not needed.

    1093:    If Dl or Dr were not set by the user, then the ones computed internally are
    1094:    returned (or a null pointer if called before PEPSetUp).

    1096: .seealso: PEPSetScale(), PEPSetUp()
    1097: @*/
    1098: PetscErrorCode PEPGetScale(PEP pep,PEPScale *scale,PetscReal *alpha,Vec *Dl,Vec *Dr,PetscInt *its,PetscReal *lambda)
    1099: {
    1100:   PetscFunctionBegin;
    1102:   if (scale)  *scale  = pep->scale;
    1103:   if (alpha)  *alpha  = pep->sfactor;
    1104:   if (Dl)     *Dl     = pep->Dl;
    1105:   if (Dr)     *Dr     = pep->Dr;
    1106:   if (its)    *its    = pep->sits;
    1107:   if (lambda) *lambda = pep->slambda;
    1108:   PetscFunctionReturn(PETSC_SUCCESS);
    1109: }

    1111: /*@
    1112:    PEPSetExtract - Specifies the extraction strategy to be used.

    1114:    Logically Collective

    1116:    Input Parameters:
    1117: +  pep     - the eigensolver context
    1118: -  extract - extraction strategy

    1120:    Options Database Keys:
    1121: .  -pep_extract <type> - extraction type, one of <none,norm,residual,structured>

    1123:    Level: intermediate

    1125: .seealso: PEPGetExtract()
    1126: @*/
    1127: PetscErrorCode PEPSetExtract(PEP pep,PEPExtract extract)
    1128: {
    1129:   PetscFunctionBegin;
    1132:   pep->extract = extract;
    1133:   PetscFunctionReturn(PETSC_SUCCESS);
    1134: }

    1136: /*@
    1137:    PEPGetExtract - Gets the extraction strategy used by the PEP object.

    1139:    Not Collective

    1141:    Input Parameter:
    1142: .  pep - the eigensolver context

    1144:    Output Parameter:
    1145: .  extract - extraction strategy

    1147:    Level: intermediate

    1149: .seealso: PEPSetExtract(), PEPExtract
    1150: @*/
    1151: PetscErrorCode PEPGetExtract(PEP pep,PEPExtract *extract)
    1152: {
    1153:   PetscFunctionBegin;
    1156:   *extract = pep->extract;
    1157:   PetscFunctionReturn(PETSC_SUCCESS);
    1158: }

    1160: /*@
    1161:    PEPSetRefine - Specifies the refinement type (and options) to be used
    1162:    after the solve.

    1164:    Logically Collective

    1166:    Input Parameters:
    1167: +  pep    - the polynomial eigensolver context
    1168: .  refine - refinement type
    1169: .  npart  - number of partitions of the communicator
    1170: .  tol    - the convergence tolerance
    1171: .  its    - maximum number of refinement iterations
    1172: -  scheme - which scheme to be used for solving the involved linear systems

    1174:    Options Database Keys:
    1175: +  -pep_refine <type> - refinement type, one of <none,simple,multiple>
    1176: .  -pep_refine_partitions <n> - the number of partitions
    1177: .  -pep_refine_tol <tol> - the tolerance
    1178: .  -pep_refine_its <its> - number of iterations
    1179: -  -pep_refine_scheme - to set the scheme for the linear solves

    1181:    Notes:
    1182:    By default, iterative refinement is disabled, since it may be very
    1183:    costly. There are two possible refinement strategies, simple and multiple.
    1184:    The simple approach performs iterative refinement on each of the
    1185:    converged eigenpairs individually, whereas the multiple strategy works
    1186:    with the invariant pair as a whole, refining all eigenpairs simultaneously.
    1187:    The latter may be required for the case of multiple eigenvalues.

    1189:    In some cases, especially when using direct solvers within the
    1190:    iterative refinement method, it may be helpful for improved scalability
    1191:    to split the communicator in several partitions. The npart parameter
    1192:    indicates how many partitions to use (defaults to 1).

    1194:    The tol and its parameters specify the stopping criterion. In the simple
    1195:    method, refinement continues until the residual of each eigenpair is
    1196:    below the tolerance (tol defaults to the PEP tol, but may be set to a
    1197:    different value). In contrast, the multiple method simply performs its
    1198:    refinement iterations (just one by default).

    1200:    The scheme argument is used to change the way in which linear systems are
    1201:    solved. Possible choices are explicit, mixed block elimination (MBE),
    1202:    and Schur complement.

    1204:    Level: intermediate

    1206: .seealso: PEPGetRefine()
    1207: @*/
    1208: PetscErrorCode PEPSetRefine(PEP pep,PEPRefine refine,PetscInt npart,PetscReal tol,PetscInt its,PEPRefineScheme scheme)
    1209: {
    1210:   PetscMPIInt    size;

    1212:   PetscFunctionBegin;
    1219:   pep->refine = refine;
    1220:   if (refine) {  /* process parameters only if not REFINE_NONE */
    1221:     if (npart!=pep->npart) {
    1222:       PetscCall(PetscSubcommDestroy(&pep->refinesubc));
    1223:       PetscCall(KSPDestroy(&pep->refineksp));
    1224:     }
    1225:     if (npart == PETSC_DEFAULT || npart == PETSC_DECIDE) {
    1226:       pep->npart = 1;
    1227:     } else {
    1228:       PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pep),&size));
    1229:       PetscCheck(npart>0 && npart<=size,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of npart");
    1230:       pep->npart = npart;
    1231:     }
    1232:     if (tol == (PetscReal)PETSC_DEFAULT || tol == (PetscReal)PETSC_DECIDE) {
    1233:       pep->rtol = PETSC_DEFAULT;
    1234:     } else {
    1235:       PetscCheck(tol>0.0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of tol. Must be > 0");
    1236:       pep->rtol = tol;
    1237:     }
    1238:     if (its==PETSC_DECIDE || its==PETSC_DEFAULT) {
    1239:       pep->rits = PETSC_DEFAULT;
    1240:     } else {
    1241:       PetscCheck(its>=0,PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of its. Must be >= 0");
    1242:       pep->rits = its;
    1243:     }
    1244:     pep->scheme = scheme;
    1245:   }
    1246:   pep->state = PEP_STATE_INITIAL;
    1247:   PetscFunctionReturn(PETSC_SUCCESS);
    1248: }

    1250: /*@C
    1251:    PEPGetRefine - Gets the refinement strategy used by the PEP object, and the
    1252:    associated parameters.

    1254:    Not Collective

    1256:    Input Parameter:
    1257: .  pep - the polynomial eigensolver context

    1259:    Output Parameters:
    1260: +  refine - refinement type
    1261: .  npart  - number of partitions of the communicator
    1262: .  tol    - the convergence tolerance
    1263: .  its    - maximum number of refinement iterations
    1264: -  scheme - the scheme used for solving linear systems

    1266:    Level: intermediate

    1268:    Note:
    1269:    The user can specify NULL for any parameter that is not needed.

    1271: .seealso: PEPSetRefine()
    1272: @*/
    1273: PetscErrorCode PEPGetRefine(PEP pep,PEPRefine *refine,PetscInt *npart,PetscReal *tol,PetscInt *its,PEPRefineScheme *scheme)
    1274: {
    1275:   PetscFunctionBegin;
    1277:   if (refine) *refine = pep->refine;
    1278:   if (npart)  *npart  = pep->npart;
    1279:   if (tol)    *tol    = pep->rtol;
    1280:   if (its)    *its    = pep->rits;
    1281:   if (scheme) *scheme = pep->scheme;
    1282:   PetscFunctionReturn(PETSC_SUCCESS);
    1283: }

    1285: /*@C
    1286:    PEPSetOptionsPrefix - Sets the prefix used for searching for all
    1287:    PEP options in the database.

    1289:    Logically Collective

    1291:    Input Parameters:
    1292: +  pep - the polynomial eigensolver context
    1293: -  prefix - the prefix string to prepend to all PEP option requests

    1295:    Notes:
    1296:    A hyphen (-) must NOT be given at the beginning of the prefix name.
    1297:    The first character of all runtime options is AUTOMATICALLY the
    1298:    hyphen.

    1300:    For example, to distinguish between the runtime options for two
    1301:    different PEP contexts, one could call
    1302: .vb
    1303:       PEPSetOptionsPrefix(pep1,"qeig1_")
    1304:       PEPSetOptionsPrefix(pep2,"qeig2_")
    1305: .ve

    1307:    Level: advanced

    1309: .seealso: PEPAppendOptionsPrefix(), PEPGetOptionsPrefix()
    1310: @*/
    1311: PetscErrorCode PEPSetOptionsPrefix(PEP pep,const char *prefix)
    1312: {
    1313:   PetscFunctionBegin;
    1315:   if (!pep->st) PetscCall(PEPGetST(pep,&pep->st));
    1316:   PetscCall(STSetOptionsPrefix(pep->st,prefix));
    1317:   if (!pep->V) PetscCall(PEPGetBV(pep,&pep->V));
    1318:   PetscCall(BVSetOptionsPrefix(pep->V,prefix));
    1319:   if (!pep->ds) PetscCall(PEPGetDS(pep,&pep->ds));
    1320:   PetscCall(DSSetOptionsPrefix(pep->ds,prefix));
    1321:   if (!pep->rg) PetscCall(PEPGetRG(pep,&pep->rg));
    1322:   PetscCall(RGSetOptionsPrefix(pep->rg,prefix));
    1323:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)pep,prefix));
    1324:   PetscFunctionReturn(PETSC_SUCCESS);
    1325: }

    1327: /*@C
    1328:    PEPAppendOptionsPrefix - Appends to the prefix used for searching for all
    1329:    PEP options in the database.

    1331:    Logically Collective

    1333:    Input Parameters:
    1334: +  pep - the polynomial eigensolver context
    1335: -  prefix - the prefix string to prepend to all PEP option requests

    1337:    Notes:
    1338:    A hyphen (-) must NOT be given at the beginning of the prefix name.
    1339:    The first character of all runtime options is AUTOMATICALLY the hyphen.

    1341:    Level: advanced

    1343: .seealso: PEPSetOptionsPrefix(), PEPGetOptionsPrefix()
    1344: @*/
    1345: PetscErrorCode PEPAppendOptionsPrefix(PEP pep,const char *prefix)
    1346: {
    1347:   PetscFunctionBegin;
    1349:   if (!pep->st) PetscCall(PEPGetST(pep,&pep->st));
    1350:   PetscCall(STAppendOptionsPrefix(pep->st,prefix));
    1351:   if (!pep->V) PetscCall(PEPGetBV(pep,&pep->V));
    1352:   PetscCall(BVAppendOptionsPrefix(pep->V,prefix));
    1353:   if (!pep->ds) PetscCall(PEPGetDS(pep,&pep->ds));
    1354:   PetscCall(DSAppendOptionsPrefix(pep->ds,prefix));
    1355:   if (!pep->rg) PetscCall(PEPGetRG(pep,&pep->rg));
    1356:   PetscCall(RGAppendOptionsPrefix(pep->rg,prefix));
    1357:   PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)pep,prefix));
    1358:   PetscFunctionReturn(PETSC_SUCCESS);
    1359: }

    1361: /*@C
    1362:    PEPGetOptionsPrefix - Gets the prefix used for searching for all
    1363:    PEP options in the database.

    1365:    Not Collective

    1367:    Input Parameters:
    1368: .  pep - the polynomial eigensolver context

    1370:    Output Parameters:
    1371: .  prefix - pointer to the prefix string used is returned

    1373:    Note:
    1374:    On the Fortran side, the user should pass in a string 'prefix' of
    1375:    sufficient length to hold the prefix.

    1377:    Level: advanced

    1379: .seealso: PEPSetOptionsPrefix(), PEPAppendOptionsPrefix()
    1380: @*/
    1381: PetscErrorCode PEPGetOptionsPrefix(PEP pep,const char *prefix[])
    1382: {
    1383:   PetscFunctionBegin;
    1386:   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)pep,prefix));
    1387:   PetscFunctionReturn(PETSC_SUCCESS);
    1388: }