Date: 2026-03-31T13:23:28+00:00

Actual source code: epsopts.c

      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:    EPS routines related to options that can be set via the command-line
     12:    or procedurally.
     13: */

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

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

     22:    Collective

     24:    Input Parameters:
     25: +  eps      - the linear 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: [](ch:eps), `EPSMonitorSet()`, `EPSSetTrackAll()`
     34: @*/
     35: PetscErrorCode EPSMonitorSetFromOptions(EPS eps,const char opt[],const char name[],PetscCtx ctx,PetscBool trackall)
     36: {
     37:   PetscErrorCode       (*mfunc)(EPS,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(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)eps),((PetscObject)eps)->options,((PetscObject)eps)->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(EPSMonitorList,key,&mfunc));
     54:   PetscCheck(mfunc,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"Specified viewer and format not supported");
     55:   PetscCall(PetscFunctionListFind(EPSMonitorCreateList,key,&cfunc));
     56:   PetscCall(PetscFunctionListFind(EPSMonitorDestroyList,key,&dfunc));
     57:   if (!cfunc) cfunc = PetscViewerAndFormatCreate_Internal;
     58:   if (!dfunc) dfunc = PetscViewerAndFormatDestroy;

     60:   PetscCall((*cfunc)(viewer,format,ctx,&vf));
     61:   PetscCall(PetscViewerDestroy(&viewer));
     62:   PetscCall(EPSMonitorSet(eps,mfunc,vf,(PetscCtxDestroyFn*)dfunc));
     63:   if (trackall) PetscCall(EPSSetTrackAll(eps,PETSC_TRUE));
     64:   PetscFunctionReturn(PETSC_SUCCESS);
     65: }

     67: /*@
     68:    EPSSetFromOptions - Sets `EPS` options from the options database.
     69:    This routine must be called before `EPSSetUp()` if the user is to be
     70:    allowed to configure the solver.

     72:    Collective

     74:    Input Parameter:
     75: .  eps - the linear eigensolver context

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

     80:    Level: beginner

     82: .seealso: [](ch:eps), `EPSSetOptionsPrefix()`
     83: @*/
     84: PetscErrorCode EPSSetFromOptions(EPS eps)
     85: {
     86:   char           type[256];
     87:   PetscBool      set,flg,flg1,flg2,flg3,bval;
     88:   PetscReal      r,array[2]={0,0};
     89:   PetscScalar    s;
     90:   PetscInt       i,j,k;
     91:   EPSBalance     bal;

     93:   PetscFunctionBegin;
     95:   PetscCall(EPSRegisterAll());
     96:   PetscObjectOptionsBegin((PetscObject)eps);
     97:     PetscCall(PetscOptionsFList("-eps_type","Eigensolver method","EPSSetType",EPSList,(char*)(((PetscObject)eps)->type_name?((PetscObject)eps)->type_name:EPSKRYLOVSCHUR),type,sizeof(type),&flg));
     98:     if (flg) PetscCall(EPSSetType(eps,type));
     99:     else if (!((PetscObject)eps)->type_name) PetscCall(EPSSetType(eps,EPSKRYLOVSCHUR));

    101:     PetscCall(PetscOptionsBoolGroupBegin("-eps_hermitian","Hermitian eigenvalue problem","EPSSetProblemType",&flg));
    102:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_HEP));
    103:     PetscCall(PetscOptionsBoolGroup("-eps_gen_hermitian","Generalized Hermitian eigenvalue problem","EPSSetProblemType",&flg));
    104:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_GHEP));
    105:     PetscCall(PetscOptionsBoolGroup("-eps_non_hermitian","Non-Hermitian eigenvalue problem","EPSSetProblemType",&flg));
    106:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_NHEP));
    107:     PetscCall(PetscOptionsBoolGroup("-eps_gen_non_hermitian","Generalized non-Hermitian eigenvalue problem","EPSSetProblemType",&flg));
    108:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_GNHEP));
    109:     PetscCall(PetscOptionsBoolGroup("-eps_pos_gen_non_hermitian","Generalized non-Hermitian eigenvalue problem with positive semi-definite B","EPSSetProblemType",&flg));
    110:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_PGNHEP));
    111:     PetscCall(PetscOptionsBoolGroup("-eps_gen_indefinite","Generalized Hermitian-indefinite eigenvalue problem","EPSSetProblemType",&flg));
    112:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_GHIEP));
    113:     PetscCall(PetscOptionsBoolGroup("-eps_bse","Structured Bethe-Salpeter eigenvalue problem","EPSSetProblemType",&flg));
    114:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_BSE));
    115:     PetscCall(PetscOptionsBoolGroup("-eps_hamiltonian","Structured Hamiltonian eigenvalue problem","EPSSetProblemType",&flg));
    116:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_HAMILT));
    117:     PetscCall(PetscOptionsBoolGroupEnd("-eps_lrep","Structured Linear Response eigenvalue problem","EPSSetProblemType",&flg));
    118:     if (flg) PetscCall(EPSSetProblemType(eps,EPS_LREP));

    120:     PetscCall(PetscOptionsBoolGroupBegin("-eps_ritz","Rayleigh-Ritz extraction","EPSSetExtraction",&flg));
    121:     if (flg) PetscCall(EPSSetExtraction(eps,EPS_RITZ));
    122:     PetscCall(PetscOptionsBoolGroup("-eps_harmonic","Harmonic Ritz extraction","EPSSetExtraction",&flg));
    123:     if (flg) PetscCall(EPSSetExtraction(eps,EPS_HARMONIC));
    124:     PetscCall(PetscOptionsBoolGroup("-eps_harmonic_relative","Relative harmonic Ritz extraction","EPSSetExtraction",&flg));
    125:     if (flg) PetscCall(EPSSetExtraction(eps,EPS_HARMONIC_RELATIVE));
    126:     PetscCall(PetscOptionsBoolGroup("-eps_harmonic_right","Right harmonic Ritz extraction","EPSSetExtraction",&flg));
    127:     if (flg) PetscCall(EPSSetExtraction(eps,EPS_HARMONIC_RIGHT));
    128:     PetscCall(PetscOptionsBoolGroup("-eps_harmonic_largest","Largest harmonic Ritz extraction","EPSSetExtraction",&flg));
    129:     if (flg) PetscCall(EPSSetExtraction(eps,EPS_HARMONIC_LARGEST));
    130:     PetscCall(PetscOptionsBoolGroup("-eps_refined","Refined Ritz extraction","EPSSetExtraction",&flg));
    131:     if (flg) PetscCall(EPSSetExtraction(eps,EPS_REFINED));
    132:     PetscCall(PetscOptionsBoolGroupEnd("-eps_refined_harmonic","Refined harmonic Ritz extraction","EPSSetExtraction",&flg));
    133:     if (flg) PetscCall(EPSSetExtraction(eps,EPS_REFINED_HARMONIC));

    135:     bal = eps->balance;
    136:     PetscCall(PetscOptionsEnum("-eps_balance","Balancing method","EPSSetBalance",EPSBalanceTypes,(PetscEnum)bal,(PetscEnum*)&bal,&flg1));
    137:     j = eps->balance_its;
    138:     PetscCall(PetscOptionsInt("-eps_balance_its","Number of iterations in balancing","EPSSetBalance",eps->balance_its,&j,&flg2));
    139:     r = eps->balance_cutoff;
    140:     PetscCall(PetscOptionsReal("-eps_balance_cutoff","Cutoff value in balancing","EPSSetBalance",eps->balance_cutoff,&r,&flg3));
    141:     if (flg1 || flg2 || flg3) PetscCall(EPSSetBalance(eps,bal,j,r));

    143:     i = eps->max_it;
    144:     PetscCall(PetscOptionsInt("-eps_max_it","Maximum number of iterations","EPSSetTolerances",eps->max_it,&i,&flg1));
    145:     r = eps->tol;
    146:     PetscCall(PetscOptionsReal("-eps_tol","Tolerance","EPSSetTolerances",SlepcDefaultTol(eps->tol),&r,&flg2));
    147:     if (flg1 || flg2) PetscCall(EPSSetTolerances(eps,r,i));

    149:     r = eps->thres;
    150:     PetscCall(PetscOptionsReal("-eps_threshold_absolute","Absolute threshold","EPSSetThreshold",r,&r,&flg));
    151:     if (flg) PetscCall(EPSSetThreshold(eps,r,PETSC_FALSE));
    152:     PetscCall(PetscOptionsReal("-eps_threshold_relative","Relative threshold","EPSSetThreshold",r,&r,&flg));
    153:     if (flg) PetscCall(EPSSetThreshold(eps,r,PETSC_TRUE));

    155:     PetscCall(PetscOptionsBoolGroupBegin("-eps_conv_rel","Relative error convergence test","EPSSetConvergenceTest",&flg));
    156:     if (flg) PetscCall(EPSSetConvergenceTest(eps,EPS_CONV_REL));
    157:     PetscCall(PetscOptionsBoolGroup("-eps_conv_norm","Convergence test relative to the eigenvalue and the matrix norms","EPSSetConvergenceTest",&flg));
    158:     if (flg) PetscCall(EPSSetConvergenceTest(eps,EPS_CONV_NORM));
    159:     PetscCall(PetscOptionsBoolGroup("-eps_conv_abs","Absolute error convergence test","EPSSetConvergenceTest",&flg));
    160:     if (flg) PetscCall(EPSSetConvergenceTest(eps,EPS_CONV_ABS));
    161:     PetscCall(PetscOptionsBoolGroupEnd("-eps_conv_user","User-defined convergence test","EPSSetConvergenceTest",&flg));
    162:     if (flg) PetscCall(EPSSetConvergenceTest(eps,EPS_CONV_USER));

    164:     PetscCall(PetscOptionsBoolGroupBegin("-eps_stop_basic","Stop iteration if all eigenvalues converged or max_it reached","EPSSetStoppingTest",&flg));
    165:     if (flg) PetscCall(EPSSetStoppingTest(eps,EPS_STOP_BASIC));
    166:     PetscCall(PetscOptionsBoolGroup("-eps_stop_threshold","Stop iteration if a converged eigenvalue is below/above the threshold","EPSSetStoppingTest",&flg));
    167:     if (flg) PetscCall(EPSSetStoppingTest(eps,EPS_STOP_THRESHOLD));
    168:     PetscCall(PetscOptionsBoolGroupEnd("-eps_stop_user","User-defined stopping test","EPSSetStoppingTest",&flg));
    169:     if (flg) PetscCall(EPSSetStoppingTest(eps,EPS_STOP_USER));

    171:     i = eps->nev;
    172:     PetscCall(PetscOptionsInt("-eps_nev","Number of eigenvalues to compute","EPSSetDimensions",eps->nev,&i,&flg1));
    173:     if (!flg1) i = PETSC_CURRENT;
    174:     j = eps->ncv;
    175:     PetscCall(PetscOptionsInt("-eps_ncv","Number of basis vectors","EPSSetDimensions",eps->ncv,&j,&flg2));
    176:     k = eps->mpd;
    177:     PetscCall(PetscOptionsInt("-eps_mpd","Maximum dimension of projected problem","EPSSetDimensions",eps->mpd,&k,&flg3));
    178:     if (flg1 || flg2 || flg3) PetscCall(EPSSetDimensions(eps,i,j,k));

    180:     PetscCall(PetscOptionsBoolGroupBegin("-eps_largest_magnitude","Compute largest eigenvalues in magnitude","EPSSetWhichEigenpairs",&flg));
    181:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_LARGEST_MAGNITUDE));
    182:     PetscCall(PetscOptionsBoolGroup("-eps_smallest_magnitude","Compute smallest eigenvalues in magnitude","EPSSetWhichEigenpairs",&flg));
    183:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_MAGNITUDE));
    184:     PetscCall(PetscOptionsBoolGroup("-eps_largest_real","Compute eigenvalues with largest real parts","EPSSetWhichEigenpairs",&flg));
    185:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_LARGEST_REAL));
    186:     PetscCall(PetscOptionsBoolGroup("-eps_smallest_real","Compute eigenvalues with smallest real parts","EPSSetWhichEigenpairs",&flg));
    187:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL));
    188:     PetscCall(PetscOptionsBoolGroup("-eps_largest_imaginary","Compute eigenvalues with largest imaginary parts","EPSSetWhichEigenpairs",&flg));
    189:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_LARGEST_IMAGINARY));
    190:     PetscCall(PetscOptionsBoolGroup("-eps_smallest_imaginary","Compute eigenvalues with smallest imaginary parts","EPSSetWhichEigenpairs",&flg));
    191:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_IMAGINARY));
    192:     PetscCall(PetscOptionsBoolGroup("-eps_target_magnitude","Compute eigenvalues closest to target","EPSSetWhichEigenpairs",&flg));
    193:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE));
    194:     PetscCall(PetscOptionsBoolGroup("-eps_target_real","Compute eigenvalues with real parts closest to target","EPSSetWhichEigenpairs",&flg));
    195:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_TARGET_REAL));
    196:     PetscCall(PetscOptionsBoolGroup("-eps_target_imaginary","Compute eigenvalues with imaginary parts closest to target","EPSSetWhichEigenpairs",&flg));
    197:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_TARGET_IMAGINARY));
    198:     PetscCall(PetscOptionsBoolGroup("-eps_all","Compute all eigenvalues in an interval or a region","EPSSetWhichEigenpairs",&flg));
    199:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_ALL));
    200:     PetscCall(PetscOptionsBoolGroupEnd("-eps_which_user","Select the user-defined selection criterion","EPSSetWhichEigenpairs",&flg));
    201:     if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_WHICH_USER));

    203:     PetscCall(PetscOptionsScalar("-eps_target","Value of the target","EPSSetTarget",eps->target,&s,&flg));
    204:     if (flg) {
    205:       if (eps->which!=EPS_TARGET_REAL && eps->which!=EPS_TARGET_IMAGINARY) PetscCall(EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE));
    206:       PetscCall(EPSSetTarget(eps,s));
    207:     }

    209:     k = 2;
    210:     PetscCall(PetscOptionsRealArray("-eps_interval","Computational interval (two real values separated with a comma without spaces)","EPSSetInterval",array,&k,&flg));
    211:     if (flg) {
    212:       PetscCheck(k>1,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_SIZ,"Must pass two values in -eps_interval (comma-separated without spaces)");
    213:       PetscCall(EPSSetWhichEigenpairs(eps,EPS_ALL));
    214:       PetscCall(EPSSetInterval(eps,array[0],array[1]));
    215:     }

    217:     PetscCall(PetscOptionsBool("-eps_true_residual","Compute true residuals explicitly","EPSSetTrueResidual",eps->trueres,&eps->trueres,NULL));
    218:     PetscCall(PetscOptionsBool("-eps_purify","Postprocess eigenvectors for purification","EPSSetPurify",eps->purify,&bval,&flg));
    219:     if (flg) PetscCall(EPSSetPurify(eps,bval));
    220:     PetscCall(PetscOptionsBool("-eps_two_sided","Use two-sided variant (to compute left eigenvectors)","EPSSetTwoSided",eps->twosided,&bval,&flg));
    221:     if (flg) PetscCall(EPSSetTwoSided(eps,bval));

    223:     /* -----------------------------------------------------------------------*/
    224:     /*
    225:       Cancels all monitors hardwired into code before call to EPSSetFromOptions()
    226:     */
    227:     PetscCall(PetscOptionsBool("-eps_monitor_cancel","Remove any hardwired monitor routines","EPSMonitorCancel",PETSC_FALSE,&flg,&set));
    228:     if (set && flg) PetscCall(EPSMonitorCancel(eps));
    229:     PetscCall(EPSMonitorSetFromOptions(eps,"-eps_monitor","first_approximation",NULL,PETSC_FALSE));
    230:     PetscCall(EPSMonitorSetFromOptions(eps,"-eps_monitor_all","all_approximations",NULL,PETSC_TRUE));
    231:     PetscCall(EPSMonitorSetFromOptions(eps,"-eps_monitor_conv","convergence_history",NULL,PETSC_FALSE));

    233:     /* -----------------------------------------------------------------------*/
    234:     PetscCall(PetscOptionsName("-eps_view","Print detailed information on solver used","EPSView",&set));
    235:     PetscCall(PetscOptionsName("-eps_view_vectors","View computed eigenvectors","EPSVectorsView",&set));
    236:     PetscCall(PetscOptionsName("-eps_view_values","View computed eigenvalues","EPSValuesView",&set));
    237:     PetscCall(PetscOptionsName("-eps_converged_reason","Print reason for convergence, and number of iterations","EPSConvergedReasonView",&set));
    238:     PetscCall(PetscOptionsName("-eps_error_absolute","Print absolute errors of each eigenpair","EPSErrorView",&set));
    239:     PetscCall(PetscOptionsName("-eps_error_relative","Print relative errors of each eigenpair","EPSErrorView",&set));
    240:     PetscCall(PetscOptionsName("-eps_error_backward","Print backward errors of each eigenpair","EPSErrorView",&set));

    242:     PetscTryTypeMethod(eps,setfromoptions,PetscOptionsObject);
    243:     PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)eps,PetscOptionsObject));
    244:   PetscOptionsEnd();

    246:   if (!eps->V) PetscCall(EPSGetBV(eps,&eps->V));
    247:   PetscCall(BVSetFromOptions(eps->V));
    248:   if (!eps->rg) PetscCall(EPSGetRG(eps,&eps->rg));
    249:   PetscCall(RGSetFromOptions(eps->rg));
    250:   if (eps->useds) {
    251:     if (!eps->ds) PetscCall(EPSGetDS(eps,&eps->ds));
    252:     PetscCall(EPSSetDSType(eps));
    253:     PetscCall(DSSetFromOptions(eps->ds));
    254:   }
    255:   if (!eps->st) PetscCall(EPSGetST(eps,&eps->st));
    256:   PetscCall(EPSSetDefaultST(eps));
    257:   PetscCall(STSetFromOptions(eps->st));
    258:   PetscFunctionReturn(PETSC_SUCCESS);
    259: }

    261: /*@
    262:    EPSGetTolerances - Gets the tolerance and maximum iteration count used
    263:    by the `EPS` convergence tests.

    265:    Not Collective

    267:    Input Parameter:
    268: .  eps - the linear eigensolver context

    270:    Output Parameters:
    271: +  tol - the convergence tolerance
    272: -  maxits - maximum number of iterations

    274:    Notes:
    275:    The user can specify `NULL` for any parameter that is not needed.

    277:    Level: intermediate

    279: .seealso: [](ch:eps), `EPSSetTolerances()`
    280: @*/
    281: PetscErrorCode EPSGetTolerances(EPS eps,PetscReal *tol,PetscInt *maxits)
    282: {
    283:   PetscFunctionBegin;
    285:   if (tol)    *tol    = eps->tol;
    286:   if (maxits) *maxits = eps->max_it;
    287:   PetscFunctionReturn(PETSC_SUCCESS);
    288: }

    290: /*@
    291:    EPSSetTolerances - Sets the tolerance and maximum iteration count used
    292:    by the `EPS` convergence tests.

    294:    Logically Collective

    296:    Input Parameters:
    297: +  eps    - the linear eigensolver context
    298: .  tol    - the convergence tolerance
    299: -  maxits - maximum number of iterations to use

    301:    Options Database Keys:
    302: +  -eps_tol tol       - sets the convergence tolerance
    303: -  -eps_max_it maxits - sets the maximum number of iterations allowed

    305:    Note:
    306:    Use `PETSC_CURRENT` to retain the current value of any of the parameters.
    307:    Use `PETSC_DETERMINE` for either argument to assign a default value computed
    308:    internally (may be different in each solver).
    309:    For `maxits` use `PETSC_UNLIMITED` to indicate there is no upper bound on this value.

    311:    Level: intermediate

    313: .seealso: [](ch:eps), `EPSGetTolerances()`
    314: @*/
    315: PetscErrorCode EPSSetTolerances(EPS eps,PetscReal tol,PetscInt maxits)
    316: {
    317:   PetscFunctionBegin;
    321:   if (tol == (PetscReal)PETSC_DETERMINE) {
    322:     eps->tol   = PETSC_DETERMINE;
    323:     eps->state = EPS_STATE_INITIAL;
    324:   } else if (tol != (PetscReal)PETSC_CURRENT) {
    325:     PetscCheck(tol>0.0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of tol. Must be > 0");
    326:     eps->tol = tol;
    327:   }
    328:   if (maxits == PETSC_DETERMINE) {
    329:     eps->max_it = PETSC_DETERMINE;
    330:     eps->state  = EPS_STATE_INITIAL;
    331:   } else if (maxits == PETSC_UNLIMITED) {
    332:     eps->max_it = PETSC_INT_MAX;
    333:   } else if (maxits != PETSC_CURRENT) {
    334:     PetscCheck(maxits>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of maxits. Must be > 0");
    335:     eps->max_it = maxits;
    336:   }
    337:   PetscFunctionReturn(PETSC_SUCCESS);
    338: }

    340: /*@
    341:    EPSGetDimensions - Gets the number of eigenvalues to compute
    342:    and the dimension of the subspace.

    344:    Not Collective

    346:    Input Parameter:
    347: .  eps - the linear eigensolver context

    349:    Output Parameters:
    350: +  nev - number of eigenvalues to compute
    351: .  ncv - the maximum dimension of the subspace to be used by the solver
    352: -  mpd - the maximum dimension allowed for the projected problem

    354:    Level: intermediate

    356: .seealso: [](ch:eps), `EPSSetDimensions()`
    357: @*/
    358: PetscErrorCode EPSGetDimensions(EPS eps,PetscInt *nev,PetscInt *ncv,PetscInt *mpd)
    359: {
    360:   PetscFunctionBegin;
    362:   if (nev) *nev = eps->nev? eps->nev: 1;
    363:   if (ncv) *ncv = eps->ncv;
    364:   if (mpd) *mpd = eps->mpd;
    365:   PetscFunctionReturn(PETSC_SUCCESS);
    366: }

    368: /*@
    369:    EPSSetDimensions - Sets the number of eigenvalues to compute
    370:    and the dimension of the subspace.

    372:    Logically Collective

    374:    Input Parameters:
    375: +  eps - the linear eigensolver context
    376: .  nev - number of eigenvalues to compute
    377: .  ncv - the maximum dimension of the subspace to be used by the solver
    378: -  mpd - the maximum dimension allowed for the projected problem

    380:    Options Database Keys:
    381: +  -eps_nev nev - sets the number of eigenvalues
    382: .  -eps_ncv ncv - sets the dimension of the subspace
    383: -  -eps_mpd mpd - sets the maximum projected dimension

    385:    Notes:
    386:    Use `PETSC_DETERMINE` for `ncv` and `mpd` to assign a reasonably good value, which is
    387:    dependent on the solution method. For any of the arguments, use `PETSC_CURRENT`
    388:    to preserve the current value.

    390:    The parameters `ncv` and `mpd` are intimately related, so that the user is advised
    391:    to set one of them at most. Normal usage is\:

    393:     1. In cases where `nev` is small, the user sets `ncv` (a reasonable default is `2*nev`).
    394:     2. In cases where `nev` is large, the user sets `mpd`.

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

    400:    When computing all eigenvalues in an interval, see `EPSSetInterval()`, these
    401:    parameters lose relevance, and tuning must be done with
    402:    `EPSKrylovSchurSetDimensions()`.

    404:    Level: intermediate

    406: .seealso: [](ch:eps), `EPSGetDimensions()`, `EPSSetInterval()`, `EPSKrylovSchurSetDimensions()`
    407: @*/
    408: PetscErrorCode EPSSetDimensions(EPS eps,PetscInt nev,PetscInt ncv,PetscInt mpd)
    409: {
    410:   PetscFunctionBegin;
    415:   if (nev != PETSC_CURRENT) {
    416:     PetscCheck(nev>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of nev. Must be > 0");
    417:     eps->nev = nev;
    418:   }
    419:   if (ncv == PETSC_DETERMINE) {
    420:     eps->ncv = PETSC_DETERMINE;
    421:   } else if (ncv != PETSC_CURRENT) {
    422:     PetscCheck(ncv>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of ncv. Must be > 0");
    423:     eps->ncv = ncv;
    424:   }
    425:   if (mpd == PETSC_DETERMINE) {
    426:     eps->mpd = PETSC_DETERMINE;
    427:   } else if (mpd != PETSC_CURRENT) {
    428:     PetscCheck(mpd>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of mpd. Must be > 0");
    429:     eps->mpd = mpd;
    430:   }
    431:   eps->state = EPS_STATE_INITIAL;
    432:   PetscFunctionReturn(PETSC_SUCCESS);
    433: }

    435: /*@
    436:    EPSSetWhichEigenpairs - Specifies which portion of the spectrum is
    437:    to be sought.

    439:    Logically Collective

    441:    Input Parameters:
    442: +  eps   - the linear eigensolver context
    443: -  which - the portion of the spectrum to be sought, see `EPSWhich` for possible values

    445:    Options Database Keys:
    446: +  -eps_largest_magnitude  - sets largest eigenvalues in magnitude
    447: .  -eps_smallest_magnitude - sets smallest eigenvalues in magnitude
    448: .  -eps_largest_real       - sets largest real parts
    449: .  -eps_smallest_real      - sets smallest real parts
    450: .  -eps_largest_imaginary  - sets largest imaginary parts
    451: .  -eps_smallest_imaginary - sets smallest imaginary parts
    452: .  -eps_target_magnitude   - sets eigenvalues closest to target
    453: .  -eps_target_real        - sets real parts closest to target
    454: .  -eps_target_imaginary   - sets imaginary parts closest to target
    455: .  -eps_all                - sets all eigenvalues in an interval or region
    456: -  -eps_which_user         - select the user-defined selection criterion

    458:    Notes:
    459:    Not all eigensolvers implemented in `EPS` account for all the possible values
    460:    of `which`. Also, some values make sense only for certain types of
    461:    problems. If SLEPc is compiled for real numbers `EPS_LARGEST_IMAGINARY`
    462:    and `EPS_SMALLEST_IMAGINARY` use the absolute value of the imaginary part
    463:    for eigenvalue selection.

    465:    The target is a scalar value provided with `EPSSetTarget()`.

    467:    The criterion `EPS_TARGET_IMAGINARY` is available only in case PETSc and
    468:    SLEPc have been built with complex scalars.

    470:    `EPS_ALL` is intended for use in combination with an interval (see
    471:    `EPSSetInterval()`), when all eigenvalues within the interval are requested,
    472:    or in the context of the `EPSCISS` solver for computing all eigenvalues in a region.

    474:    Level: intermediate

    476: .seealso: [](ch:eps), `EPSGetWhichEigenpairs()`, `EPSSetTarget()`, `EPSSetInterval()`, `EPSSetDimensions()`, `EPSSetEigenvalueComparison()`, `EPSWhich`
    477: @*/
    478: PetscErrorCode EPSSetWhichEigenpairs(EPS eps,EPSWhich which)
    479: {
    480:   PetscFunctionBegin;
    483:   switch (which) {
    484:     case EPS_LARGEST_MAGNITUDE:
    485:     case EPS_SMALLEST_MAGNITUDE:
    486:     case EPS_LARGEST_REAL:
    487:     case EPS_SMALLEST_REAL:
    488:     case EPS_LARGEST_IMAGINARY:
    489:     case EPS_SMALLEST_IMAGINARY:
    490:     case EPS_TARGET_MAGNITUDE:
    491:     case EPS_TARGET_REAL:
    492: #if defined(PETSC_USE_COMPLEX)
    493:     case EPS_TARGET_IMAGINARY:
    494: #endif
    495:     case EPS_ALL:
    496:     case EPS_WHICH_USER:
    497:       if (eps->which != which) {
    498:         eps->state = EPS_STATE_INITIAL;
    499:         eps->which = which;
    500:       }
    501:       break;
    502: #if !defined(PETSC_USE_COMPLEX)
    503:     case EPS_TARGET_IMAGINARY:
    504:       SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"EPS_TARGET_IMAGINARY can be used only with complex scalars");
    505: #endif
    506:     default:
    507:       SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'which' value");
    508:   }
    509:   PetscFunctionReturn(PETSC_SUCCESS);
    510: }

    512: /*@
    513:    EPSGetWhichEigenpairs - Returns which portion of the spectrum is to be
    514:    sought.

    516:    Not Collective

    518:    Input Parameter:
    519: .  eps - the linear eigensolver context

    521:    Output Parameter:
    522: .  which - the portion of the spectrum to be sought, see `EPSWhich` for possible values

    524:    Level: intermediate

    526: .seealso: [](ch:eps), `EPSSetWhichEigenpairs()`, `EPSWhich`
    527: @*/
    528: PetscErrorCode EPSGetWhichEigenpairs(EPS eps,EPSWhich *which)
    529: {
    530:   PetscFunctionBegin;
    532:   PetscAssertPointer(which,2);
    533:   *which = eps->which;
    534:   PetscFunctionReturn(PETSC_SUCCESS);
    535: }

    537: /*@
    538:    EPSSetThreshold - Sets the threshold used in the threshold stopping test.

    540:    Logically Collective

    542:    Input Parameters:
    543: +  eps   - the linear eigensolver context
    544: .  thres - the threshold value
    545: -  rel   - whether the threshold is relative or not

    547:    Options Database Keys:
    548: +  -eps_threshold_absolute thres - sets an absolute threshold
    549: -  -eps_threshold_relative thres - sets a relative threshold

    551:    Notes:
    552:    This function internally calls `EPSSetStoppingTest()` to set a special stopping
    553:    test based on the threshold, where eigenvalues are computed in sequence until
    554:    one of the computed eigenvalues is below the threshold `thres` (in magnitude).
    555:    This is the interpretation in case of searching for largest eigenvalues in magnitude,
    556:    see `EPSSetWhichEigenpairs()`.

    558:    If the solver is configured to compute smallest magnitude eigenvalues, then the
    559:    threshold must be interpreted in the opposite direction, i.e., the computation
    560:    will stop when one of the computed values is above the threshold (in magnitude).

    562:    The threshold can also be used when computing largest/smallest real eigenvalues
    563:    (i.e, rightmost or leftmost), in which case the threshold is allowed to be
    564:    negative. The solver will stop when one of the computed eigenvalues is above
    565:    or below the threshold (considering the real part of the eigenvalue). This mode
    566:    is allowed only in problem types whose eigenvalues are always real (e.g., `EPS_HEP`).

    568:    In the case of largest magnitude eigenvalues, the threshold can be made relative
    569:    with respect to the dominant eigenvalue. Otherwise, the argument `rel` should be
    570:    `PETSC_FALSE`.

    572:    An additional use case is with target magnitude selection of eigenvalues (e.g.,
    573:    with shift-and-invert), but this must be used with caution to avoid unexpected
    574:    behavior. With an absolute threshold, the solver will assume that leftmost
    575:    eigenvalues are being computed (e.g., with `target`=0 for a problem with real
    576:    positive eigenvalues). In case of a relative threshold, a value of `thres`<1
    577:    implies that the wanted eigenvalues are the largest ones, and otherwise the
    578:    solver assumes that smallest eigenvalues are being computed.

    580:    The test against the threshold is done for converged eigenvalues, which
    581:    implies that the final number of converged eigenvalues will be at least
    582:    one more than the actual number of values below/above the threshold.

    584:    Since the number of computed eigenvalues is not known a priori, the solver
    585:    will need to reallocate the basis of vectors internally, to have enough room
    586:    to accommodate all the eigenvectors. Hence, this option must be used with
    587:    caution to avoid out-of-memory problems. The recommendation is to set the value
    588:    of `ncv` to be larger than the estimated number of eigenvalues, to minimize the
    589:    number of reallocations.

    591:    If a number of wanted eigenvalues has been set with `EPSSetDimensions()`
    592:    it is also taken into account and the solver will stop when one of the two
    593:    conditions (threshold or number of converged values) is met.

    595:    Use `EPSSetStoppingTest()` to return to the usual computation of a fixed number
    596:    of eigenvalues.

    598:    Level: advanced

    600: .seealso: [](ch:eps), `EPSGetThreshold()`, `EPSSetStoppingTest()`, `EPSSetDimensions()`, `EPSSetWhichEigenpairs()`, `EPSSetProblemType()`
    601: @*/
    602: PetscErrorCode EPSSetThreshold(EPS eps,PetscReal thres,PetscBool rel)
    603: {
    604:   PetscFunctionBegin;
    608:   if (eps->thres != thres || eps->threlative != rel) {
    609:     eps->thres = thres;
    610:     eps->threlative = rel;
    611:     eps->state = EPS_STATE_INITIAL;
    612:     PetscCall(EPSSetStoppingTest(eps,EPS_STOP_THRESHOLD));
    613:   }
    614:   PetscFunctionReturn(PETSC_SUCCESS);
    615: }

    617: /*@
    618:    EPSGetThreshold - Gets the threshold used by the threshold stopping test.

    620:    Not Collective

    622:    Input Parameter:
    623: .  eps - the linear eigensolver context

    625:    Output Parameters:
    626: +  thres - the threshold
    627: -  rel   - whether the threshold is relative or not

    629:    Level: advanced

    631: .seealso: [](ch:eps), `EPSSetThreshold()`
    632: @*/
    633: PetscErrorCode EPSGetThreshold(EPS eps,PetscReal *thres,PetscBool *rel)
    634: {
    635:   PetscFunctionBegin;
    637:   if (thres) *thres = eps->thres;
    638:   if (rel)   *rel   = eps->threlative;
    639:   PetscFunctionReturn(PETSC_SUCCESS);
    640: }

    642: /*@C
    643:    EPSSetEigenvalueComparison - Specifies the eigenvalue comparison function
    644:    when `EPSSetWhichEigenpairs()` is set to `EPS_WHICH_USER`.

    646:    Logically Collective

    648:    Input Parameters:
    649: +  eps  - the linear eigensolver context
    650: .  func - the comparison function, see `SlepcEigenvalueComparisonFn` for the calling sequence
    651: -  ctx  - a context pointer (the last parameter to the comparison function)

    653:    Level: advanced

    655: .seealso: [](ch:eps), `EPSSetWhichEigenpairs()`, `EPSWhich`
    656: @*/
    657: PetscErrorCode EPSSetEigenvalueComparison(EPS eps,SlepcEigenvalueComparisonFn *func,PetscCtx ctx)
    658: {
    659:   PetscFunctionBegin;
    661:   eps->sc->comparison    = func;
    662:   eps->sc->comparisonctx = ctx;
    663:   eps->which             = EPS_WHICH_USER;
    664:   PetscFunctionReturn(PETSC_SUCCESS);
    665: }

    667: /*@C
    668:    EPSSetArbitrarySelection - Specifies a function intended to look for
    669:    eigenvalues according to an arbitrary selection criterion. This criterion
    670:    can be based on a computation involving the current eigenvector approximation.

    672:    Logically Collective

    674:    Input Parameters:
    675: +  eps  - the linear eigensolver context
    676: .  func - the arbitrary selection function, see `SlepcArbitrarySelectionFn` for a calling sequence
    677: -  ctx  - a context pointer (the last parameter to the arbitrary selection function)

    679:    Notes:
    680:    This provides a mechanism to select eigenpairs by evaluating a user-defined
    681:    function. When a function has been provided, the default selection based on
    682:    sorting the eigenvalues is replaced by the sorting of the results of this
    683:    function (with the same sorting criterion given in `EPSSetWhichEigenpairs()`).

    685:    For instance, suppose you want to compute those eigenvectors that maximize
    686:    a certain computable expression. Then implement the computation using
    687:    the arguments `xr` and `xi`, and return the result in `rr`. Then set the standard
    688:    sorting by magnitude so that the eigenpair with largest value of `rr` is
    689:    selected.

    691:    This evaluation function is collective, that is, all processes call it and
    692:    it can use collective operations; furthermore, the computed result must
    693:    be the same in all processes.

    695:    The result of `func` is expressed as a complex number so that it is possible to
    696:    use the standard eigenvalue sorting functions, but normally only `rr` is used.
    697:    Set `ri` to zero unless it is meaningful in your application.

    699:    Level: advanced

    701: .seealso: [](ch:eps), `EPSSetWhichEigenpairs()`, `EPSSetArbitrarySelectionContextDestroy()`
    702: @*/
    703: PetscErrorCode EPSSetArbitrarySelection(EPS eps,SlepcArbitrarySelectionFn *func,PetscCtx ctx)
    704: {
    705:   PetscFunctionBegin;
    707:   if (eps->arbitrarydestroy) PetscCall((*eps->arbitrarydestroy)(&eps->arbitraryctx));
    708:   eps->arbitrary    = func;
    709:   eps->arbitraryctx = ctx;
    710:   eps->state        = EPS_STATE_INITIAL;
    711:   PetscFunctionReturn(PETSC_SUCCESS);
    712: }

    714: /*@C
    715:    EPSSetArbitrarySelectionContextDestroy - Set a context destroy function for the
    716:    context used in the arbitrary selection.

    718:    Logically Collective

    720:    Input Parameters:
    721: +  eps     - the linear eigensolver context
    722: -  destroy - context destroy function, see `PetscCtxDestroyFn` for its calling sequence

    724:    Level: advanced

    726: .seealso: [](ch:eps), `EPSSetArbitrarySelection()`
    727: @*/
    728: PetscErrorCode EPSSetArbitrarySelectionContextDestroy(EPS eps,PetscCtxDestroyFn *destroy)
    729: {
    730:   PetscFunctionBegin;
    732:   eps->arbitrarydestroy = destroy;
    733:   PetscFunctionReturn(PETSC_SUCCESS);
    734: }

    736: /*@C
    737:    EPSSetConvergenceTestFunction - Sets a function to compute the error estimate
    738:    used in the convergence test.

    740:    Logically Collective

    742:    Input Parameters:
    743: +  eps     - the linear eigensolver context
    744: .  func    - convergence test function, see `EPSConvergenceTestFn` for the calling sequence
    745: .  ctx     - context for private data for the convergence routine (may be `NULL`)
    746: -  destroy - a routine for destroying the context (may be `NULL`), see `PetscCtxDestroyFn`
    747:              for the calling sequence

    749:    Notes:
    750:    When this is called with a user-defined function, then the convergence
    751:    criterion is set to `EPS_CONV_USER`, see `EPSSetConvergenceTest()`.

    753:    If the error estimate returned by the convergence test function is less than
    754:    the tolerance, then the eigenvalue is accepted as converged.

    756:    Level: advanced

    758: .seealso: [](ch:eps), `EPSSetConvergenceTest()`, `EPSSetTolerances()`
    759: @*/
    760: PetscErrorCode EPSSetConvergenceTestFunction(EPS eps,EPSConvergenceTestFn *func,PetscCtx ctx,PetscCtxDestroyFn *destroy)
    761: {
    762:   PetscFunctionBegin;
    764:   if (eps->convergeddestroy) PetscCall((*eps->convergeddestroy)(&eps->convergedctx));
    765:   eps->convergeduser    = func;
    766:   eps->convergeddestroy = destroy;
    767:   eps->convergedctx     = ctx;
    768:   if (func == EPSConvergedRelative) eps->conv = EPS_CONV_REL;
    769:   else if (func == EPSConvergedNorm) eps->conv = EPS_CONV_NORM;
    770:   else if (func == EPSConvergedAbsolute) eps->conv = EPS_CONV_ABS;
    771:   else {
    772:     eps->conv      = EPS_CONV_USER;
    773:     eps->converged = eps->convergeduser;
    774:   }
    775:   PetscFunctionReturn(PETSC_SUCCESS);
    776: }

    778: /*@
    779:    EPSSetConvergenceTest - Specifies how to compute the error estimate
    780:    used in the convergence test.

    782:    Logically Collective

    784:    Input Parameters:
    785: +  eps  - the linear eigensolver context
    786: -  conv - the type of convergence test, see `EPSConv` for possible values

    788:    Options Database Keys:
    789: +  -eps_conv_abs  - sets the absolute convergence test
    790: .  -eps_conv_rel  - sets the convergence test relative to the eigenvalue
    791: .  -eps_conv_norm - sets the convergence test relative to the matrix norms
    792: -  -eps_conv_user - selects the user-defined convergence test

    794:    Level: intermediate

    796: .seealso: [](ch:eps), `EPSGetConvergenceTest()`, `EPSSetConvergenceTestFunction()`, `EPSSetStoppingTest()`, `EPSConv`
    797: @*/
    798: PetscErrorCode EPSSetConvergenceTest(EPS eps,EPSConv conv)
    799: {
    800:   PetscFunctionBegin;
    803:   switch (conv) {
    804:     case EPS_CONV_ABS:  eps->converged = EPSConvergedAbsolute; break;
    805:     case EPS_CONV_REL:  eps->converged = EPSConvergedRelative; break;
    806:     case EPS_CONV_NORM: eps->converged = EPSConvergedNorm; break;
    807:     case EPS_CONV_USER:
    808:       PetscCheck(eps->convergeduser,PetscObjectComm((PetscObject)eps),PETSC_ERR_ORDER,"Must call EPSSetConvergenceTestFunction() first");
    809:       eps->converged = eps->convergeduser;
    810:       break;
    811:     default:
    812:       SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'conv' value");
    813:   }
    814:   eps->conv = conv;
    815:   PetscFunctionReturn(PETSC_SUCCESS);
    816: }

    818: /*@
    819:    EPSGetConvergenceTest - Gets the method used to compute the error estimate
    820:    used in the convergence test.

    822:    Not Collective

    824:    Input Parameter:
    825: .  eps   - the linear eigensolver context

    827:    Output Parameter:
    828: .  conv  - the type of convergence test

    830:    Level: intermediate

    832: .seealso: [](ch:eps), `EPSSetConvergenceTest()`, `EPSConv`
    833: @*/
    834: PetscErrorCode EPSGetConvergenceTest(EPS eps,EPSConv *conv)
    835: {
    836:   PetscFunctionBegin;
    838:   PetscAssertPointer(conv,2);
    839:   *conv = eps->conv;
    840:   PetscFunctionReturn(PETSC_SUCCESS);
    841: }

    843: /*@C
    844:    EPSSetStoppingTestFunction - Sets a function to decide when to stop the outer
    845:    iteration of the eigensolver.

    847:    Logically Collective

    849:    Input Parameters:
    850: +  eps     - the linear eigensolver context
    851: .  func    - stopping test function, see `EPSStoppingTestFn` for the calling sequence
    852: .  ctx     - context for private data for the stopping routine (may be `NULL`)
    853: -  destroy - a routine for destroying the context (may be `NULL`), see `PetscCtxDestroyFn`
    854:              for the calling sequence

    856:    Note:
    857:    When implementing a function for this, normal usage is to first call the
    858:    default routine `EPSStoppingBasic()` and then set `reason` to `EPS_CONVERGED_USER`
    859:    if some user-defined conditions have been met. To let the eigensolver continue
    860:    iterating, the result must be left as `EPS_CONVERGED_ITERATING`.

    862:    Level: advanced

    864: .seealso: [](ch:eps), `EPSSetStoppingTest()`, `EPSStoppingBasic()`
    865: @*/
    866: PetscErrorCode EPSSetStoppingTestFunction(EPS eps,EPSStoppingTestFn *func,PetscCtx ctx,PetscCtxDestroyFn *destroy)
    867: {
    868:   PetscFunctionBegin;
    870:   if (eps->stoppingdestroy) PetscCall((*eps->stoppingdestroy)(&eps->stoppingctx));
    871:   eps->stoppinguser    = func;
    872:   eps->stoppingdestroy = destroy;
    873:   eps->stoppingctx     = ctx;
    874:   if (func == EPSStoppingBasic) PetscCall(EPSSetStoppingTest(eps,EPS_STOP_BASIC));
    875:   else if (func == EPSStoppingThreshold) PetscCall(EPSSetStoppingTest(eps,EPS_STOP_THRESHOLD));
    876:   else {
    877:     eps->stop     = EPS_STOP_USER;
    878:     eps->stopping = eps->stoppinguser;
    879:   }
    880:   PetscFunctionReturn(PETSC_SUCCESS);
    881: }

    883: /*@
    884:    EPSSetStoppingTest - Specifies how to decide the termination of the outer
    885:    loop of the eigensolver.

    887:    Logically Collective

    889:    Input Parameters:
    890: +  eps  - the linear eigensolver context
    891: -  stop - the type of stopping test, see `EPSStop`

    893:    Options Database Keys:
    894: +  -eps_stop_basic     - sets the default stopping test
    895: .  -eps_stop_threshold - sets the threshold stopping test
    896: -  -eps_stop_user      - selects the user-defined stopping test

    898:    Level: advanced

    900: .seealso: [](ch:eps), `EPSGetStoppingTest()`, `EPSSetStoppingTestFunction()`, `EPSSetConvergenceTest()`, `EPSStop`
    901: @*/
    902: PetscErrorCode EPSSetStoppingTest(EPS eps,EPSStop stop)
    903: {
    904:   PetscFunctionBegin;
    907:   switch (stop) {
    908:     case EPS_STOP_BASIC: eps->stopping = EPSStoppingBasic; break;
    909:     case EPS_STOP_THRESHOLD: eps->stopping = EPSStoppingThreshold; break;
    910:     case EPS_STOP_USER:
    911:       PetscCheck(eps->stoppinguser,PetscObjectComm((PetscObject)eps),PETSC_ERR_ORDER,"Must call EPSSetStoppingTestFunction() first");
    912:       eps->stopping = eps->stoppinguser;
    913:       break;
    914:     default:
    915:       SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'stop' value");
    916:   }
    917:   eps->stop = stop;
    918:   PetscFunctionReturn(PETSC_SUCCESS);
    919: }

    921: /*@
    922:    EPSGetStoppingTest - Gets the method used to decide the termination of the outer
    923:    loop of the eigensolver.

    925:    Not Collective

    927:    Input Parameter:
    928: .  eps   - the linear eigensolver context

    930:    Output Parameter:
    931: .  stop  - the type of stopping test

    933:    Level: advanced

    935: .seealso: [](ch:eps), `EPSSetStoppingTest()`, `EPSStop`
    936: @*/
    937: PetscErrorCode EPSGetStoppingTest(EPS eps,EPSStop *stop)
    938: {
    939:   PetscFunctionBegin;
    941:   PetscAssertPointer(stop,2);
    942:   *stop = eps->stop;
    943:   PetscFunctionReturn(PETSC_SUCCESS);
    944: }

    946: /*@
    947:    EPSSetProblemType - Specifies the type of the eigenvalue problem.

    949:    Logically Collective

    951:    Input Parameters:
    952: +  eps  - the linear eigensolver context
    953: -  type - a known type of eigenvalue problem

    955:    Options Database Keys:
    956: +  -eps_hermitian             - Hermitian eigenvalue problem
    957: .  -eps_gen_hermitian         - generalized Hermitian eigenvalue problem
    958: .  -eps_non_hermitian         - non-Hermitian eigenvalue problem
    959: .  -eps_gen_non_hermitian     - generalized non-Hermitian eigenvalue problem
    960: .  -eps_pos_gen_non_hermitian - generalized non-Hermitian eigenvalue problem
    961:                                 with positive semi-definite $B$
    962: .  -eps_gen_indefinite        - generalized Hermitian-indefinite eigenvalue problem
    963: .  -eps_bse                   - structured Bethe-Salpeter eigenvalue problem
    964: .  -eps_hamiltonian           - structured Hamiltonian eigenvalue problem
    965: -  -eps_lrep                  - structured Linear Response eigenvalue problem

    967:    Notes:
    968:    This function must be used to instruct SLEPc to exploit symmetry or other
    969:    kind of structure. If no
    970:    problem type is specified, by default a non-Hermitian problem is assumed
    971:    (either standard or generalized). If the user knows that the problem is
    972:    Hermitian (i.e., $A=A^*$) or generalized Hermitian (i.e., $A=A^*$, $B=B^*$,
    973:    and $B$ positive definite) then it is recommended to set the problem type so
    974:    that the eigensolver can exploit these properties.

    976:    If the user does not call this function, the solver will use a reasonable
    977:    guess.

    979:    For structured problem types such as `EPS_BSE`, the matrices passed in via
    980:    `EPSSetOperators()` must have been created with the corresponding helper
    981:    function, i.e., `MatCreateBSE()`.

    983:    Level: intermediate

    985: .seealso: [](ch:eps), `EPSSetOperators()`, `EPSSetType()`, `EPSGetProblemType()`, `EPSProblemType`
    986: @*/
    987: PetscErrorCode EPSSetProblemType(EPS eps,EPSProblemType type)
    988: {
    989:   PetscFunctionBegin;
    992:   if (type == eps->problem_type) PetscFunctionReturn(PETSC_SUCCESS);
    993:   switch (type) {
    994:     case EPS_HEP:
    995:       eps->isgeneralized = PETSC_FALSE;
    996:       eps->ishermitian = PETSC_TRUE;
    997:       eps->ispositive = PETSC_FALSE;
    998:       eps->isstructured = PETSC_FALSE;
    999:       break;
    1000:     case EPS_NHEP:
    1001:       eps->isgeneralized = PETSC_FALSE;
    1002:       eps->ishermitian = PETSC_FALSE;
    1003:       eps->ispositive = PETSC_FALSE;
    1004:       eps->isstructured = PETSC_FALSE;
    1005:       break;
    1006:     case EPS_GHEP:
    1007:       eps->isgeneralized = PETSC_TRUE;
    1008:       eps->ishermitian = PETSC_TRUE;
    1009:       eps->ispositive = PETSC_TRUE;
    1010:       eps->isstructured = PETSC_FALSE;
    1011:       break;
    1012:     case EPS_GNHEP:
    1013:       eps->isgeneralized = PETSC_TRUE;
    1014:       eps->ishermitian = PETSC_FALSE;
    1015:       eps->ispositive = PETSC_FALSE;
    1016:       eps->isstructured = PETSC_FALSE;
    1017:       break;
    1018:     case EPS_PGNHEP:
    1019:       eps->isgeneralized = PETSC_TRUE;
    1020:       eps->ishermitian = PETSC_FALSE;
    1021:       eps->ispositive = PETSC_TRUE;
    1022:       eps->isstructured = PETSC_FALSE;
    1023:       break;
    1024:     case EPS_GHIEP:
    1025:       eps->isgeneralized = PETSC_TRUE;
    1026:       eps->ishermitian = PETSC_TRUE;
    1027:       eps->ispositive = PETSC_FALSE;
    1028:       eps->isstructured = PETSC_FALSE;
    1029:       break;
    1030:     case EPS_BSE:
    1031:       eps->isgeneralized = PETSC_FALSE;
    1032:       eps->ishermitian = PETSC_FALSE;
    1033:       eps->ispositive = PETSC_FALSE;
    1034:       eps->isstructured = PETSC_TRUE;
    1035:       break;
    1036:     case EPS_HAMILT:
    1037:       eps->isgeneralized = PETSC_FALSE;
    1038:       eps->ishermitian = PETSC_FALSE;
    1039:       eps->ispositive = PETSC_FALSE;
    1040:       eps->isstructured = PETSC_TRUE;
    1041:       break;
    1042:     case EPS_LREP:
    1043:       eps->isgeneralized = PETSC_FALSE;
    1044:       eps->ishermitian = PETSC_FALSE;
    1045:       eps->ispositive = PETSC_FALSE;
    1046:       eps->isstructured = PETSC_TRUE;
    1047:       break;
    1048:     default:
    1049:       SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONG,"Unknown eigenvalue problem type");
    1050:   }
    1051:   eps->problem_type = type;
    1052:   eps->state = EPS_STATE_INITIAL;
    1053:   PetscFunctionReturn(PETSC_SUCCESS);
    1054: }

    1056: /*@
    1057:    EPSGetProblemType - Gets the problem type from the `EPS` object.

    1059:    Not Collective

    1061:    Input Parameter:
    1062: .  eps - the linear eigensolver context

    1064:    Output Parameter:
    1065: .  type - the problem type

    1067:    Level: intermediate

    1069: .seealso: [](ch:eps), `EPSSetProblemType()`, `EPSProblemType`
    1070: @*/
    1071: PetscErrorCode EPSGetProblemType(EPS eps,EPSProblemType *type)
    1072: {
    1073:   PetscFunctionBegin;
    1075:   PetscAssertPointer(type,2);
    1076:   *type = eps->problem_type;
    1077:   PetscFunctionReturn(PETSC_SUCCESS);
    1078: }

    1080: /*@
    1081:    EPSSetExtraction - Specifies the type of extraction technique to be employed
    1082:    by the eigensolver.

    1084:    Logically Collective

    1086:    Input Parameters:
    1087: +  eps  - the linear eigensolver context
    1088: -  extr - a known type of extraction

    1090:    Options Database Keys:
    1091: +  -eps_ritz              - Rayleigh-Ritz extraction
    1092: .  -eps_harmonic          - harmonic Ritz extraction
    1093: .  -eps_harmonic_relative - harmonic Ritz extraction relative to the eigenvalue
    1094: .  -eps_harmonic_right    - harmonic Ritz extraction for rightmost eigenvalues
    1095: .  -eps_harmonic_largest  - harmonic Ritz extraction for largest magnitude (without target)
    1096: .  -eps_refined           - refined Ritz extraction
    1097: -  -eps_refined_harmonic  - refined harmonic Ritz extraction

    1099:    Notes:
    1100:    Not all eigensolvers support all types of extraction.

    1102:    By default, a standard Rayleigh-Ritz extraction is used. Other extractions
    1103:    may be useful when computing interior eigenvalues.

    1105:    Harmonic-type extractions are used in combination with a target, see `EPSSetTarget()`.

    1107:    Level: advanced

    1109: .seealso: [](ch:eps), [](#sec:harmonic), `EPSSetTarget()`, `EPSGetExtraction()`, `EPSExtraction`
    1110: @*/
    1111: PetscErrorCode EPSSetExtraction(EPS eps,EPSExtraction extr)
    1112: {
    1113:   PetscFunctionBegin;
    1116:   if (eps->extraction != extr) {
    1117:     eps->state      = EPS_STATE_INITIAL;
    1118:     eps->extraction = extr;
    1119:   }
    1120:   PetscFunctionReturn(PETSC_SUCCESS);
    1121: }

    1123: /*@
    1124:    EPSGetExtraction - Gets the extraction type used by the `EPS` object.

    1126:    Not Collective

    1128:    Input Parameter:
    1129: .  eps - the linear eigensolver context

    1131:    Output Parameter:
    1132: .  extr - name of extraction type

    1134:    Level: advanced

    1136: .seealso: [](ch:eps), `EPSSetExtraction()`, `EPSExtraction`
    1137: @*/
    1138: PetscErrorCode EPSGetExtraction(EPS eps,EPSExtraction *extr)
    1139: {
    1140:   PetscFunctionBegin;
    1142:   PetscAssertPointer(extr,2);
    1143:   *extr = eps->extraction;
    1144:   PetscFunctionReturn(PETSC_SUCCESS);
    1145: }

    1147: /*@
    1148:    EPSSetBalance - Specifies the balancing technique to be employed by the
    1149:    eigensolver, and some parameters associated to it.

    1151:    Logically Collective

    1153:    Input Parameters:
    1154: +  eps    - the linear eigensolver context
    1155: .  bal    - the balancing method, see `EPSBalance` for possible values
    1156: .  its    - number of iterations of the balancing algorithm
    1157: -  cutoff - cutoff value

    1159:    Options Database Keys:
    1160: +  -eps_balance (none|oneside|twoside|user) - the balancing method
    1161: .  -eps_balance_its its                     - number of iterations
    1162: -  -eps_balance_cutoff cutoff               - cutoff value

    1164:    Notes:
    1165:    When balancing is enabled, the solver works implicitly with matrix $DAD^{-1}$,
    1166:    where $D$ is an appropriate diagonal matrix. This improves the accuracy of
    1167:    the computed results in some cases, see [](sec:balancing).

    1169:    Balancing makes sense only for non-Hermitian problems when the required
    1170:    precision is high (i.e., a small tolerance such as `1e-14`).

    1172:    By default, balancing is disabled. The two-sided method is much more
    1173:    effective than the one-sided counterpart, but it requires the system
    1174:    matrices to have the `MatMultTranspose()` operation defined. The methods
    1175:    are described in {cite:p}`Che00`.

    1177:    The parameter `its` is the number of iterations performed by the method. The
    1178:    `cutoff` value is used only in the two-side variant. Use `PETSC_DETERMINE` to assign
    1179:    a reasonably good value, or `PETSC_CURRENT` to leave the value unchanged.

    1181:    User-defined balancing is allowed provided that the corresponding matrix
    1182:    is set via `STSetBalanceMatrix()`.

    1184:    Level: intermediate

    1186: .seealso: [](ch:eps), [](sec:balancing), `EPSGetBalance()`, `EPSBalance`, `STSetBalanceMatrix()`
    1187: @*/
    1188: PetscErrorCode EPSSetBalance(EPS eps,EPSBalance bal,PetscInt its,PetscReal cutoff)
    1189: {
    1190:   PetscFunctionBegin;
    1195:   switch (bal) {
    1196:     case EPS_BALANCE_NONE:
    1197:     case EPS_BALANCE_ONESIDE:
    1198:     case EPS_BALANCE_TWOSIDE:
    1199:     case EPS_BALANCE_USER:
    1200:       if (eps->balance != bal) {
    1201:         eps->state = EPS_STATE_INITIAL;
    1202:         eps->balance = bal;
    1203:       }
    1204:       break;
    1205:     default:
    1206:       SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Invalid value of argument 'bal'");
    1207:   }
    1208:   if (its==PETSC_DETERMINE) eps->balance_its = 5;
    1209:   else if (its!=PETSC_CURRENT) {
    1210:     PetscCheck(its>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of its. Must be > 0");
    1211:     eps->balance_its = its;
    1212:   }
    1213:   if (cutoff==(PetscReal)PETSC_DETERMINE) eps->balance_cutoff = 1e-8;
    1214:   else if (cutoff!=(PetscReal)PETSC_CURRENT) {
    1215:     PetscCheck(cutoff>0.0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of cutoff. Must be > 0");
    1216:     eps->balance_cutoff = cutoff;
    1217:   }
    1218:   PetscFunctionReturn(PETSC_SUCCESS);
    1219: }

    1221: /*@
    1222:    EPSGetBalance - Gets the balancing type used by the `EPS` object, and the
    1223:    associated parameters.

    1225:    Not Collective

    1227:    Input Parameter:
    1228: .  eps - the linear eigensolver context

    1230:    Output Parameters:
    1231: +  bal    - the balancing method
    1232: .  its    - number of iterations of the balancing algorithm
    1233: -  cutoff - cutoff value

    1235:    Level: intermediate

    1237:    Note:
    1238:    The user can specify `NULL` for any parameter that is not needed.

    1240: .seealso: [](ch:eps), `EPSSetBalance()`, `EPSBalance`
    1241: @*/
    1242: PetscErrorCode EPSGetBalance(EPS eps,EPSBalance *bal,PetscInt *its,PetscReal *cutoff)
    1243: {
    1244:   PetscFunctionBegin;
    1246:   if (bal)    *bal = eps->balance;
    1247:   if (its)    *its = eps->balance_its;
    1248:   if (cutoff) *cutoff = eps->balance_cutoff;
    1249:   PetscFunctionReturn(PETSC_SUCCESS);
    1250: }

    1252: /*@
    1253:    EPSSetTwoSided - Sets the solver to use a two-sided variant so that left
    1254:    eigenvectors are also computed.

    1256:    Logically Collective

    1258:    Input Parameters:
    1259: +  eps      - the linear eigensolver context
    1260: -  twosided - whether the two-sided variant is to be used or not

    1262:    Options Database Key:
    1263: .  -eps_two_sided (true|false) - toggles the twosided flag

    1265:    Notes:
    1266:    If the user sets `twosided`=`PETSC_TRUE` then the solver uses a variant of
    1267:    the algorithm that computes both right and left eigenvectors. This is
    1268:    usually much more costly. This option is not available in all solvers,
    1269:    see table [](#tab:support).

    1271:    When using two-sided solvers, the problem matrices must have both the
    1272:    `MATOP_MULT` and `MATOP_MULT_TRANSPOSE` operations defined.

    1274:    Level: advanced

    1276: .seealso: [](ch:eps), `EPSGetTwoSided()`, `EPSGetLeftEigenvector()`
    1277: @*/
    1278: PetscErrorCode EPSSetTwoSided(EPS eps,PetscBool twosided)
    1279: {
    1280:   PetscFunctionBegin;
    1283:   if (twosided!=eps->twosided) {
    1284:     eps->twosided = twosided;
    1285:     eps->state    = EPS_STATE_INITIAL;
    1286:   }
    1287:   PetscFunctionReturn(PETSC_SUCCESS);
    1288: }

    1290: /*@
    1291:    EPSGetTwoSided - Returns the flag indicating whether a two-sided variant
    1292:    of the algorithm is being used or not.

    1294:    Not Collective

    1296:    Input Parameter:
    1297: .  eps - the linear eigensolver context

    1299:    Output Parameter:
    1300: .  twosided - the returned flag

    1302:    Level: advanced

    1304: .seealso: [](ch:eps), `EPSSetTwoSided()`
    1305: @*/
    1306: PetscErrorCode EPSGetTwoSided(EPS eps,PetscBool *twosided)
    1307: {
    1308:   PetscFunctionBegin;
    1310:   PetscAssertPointer(twosided,2);
    1311:   *twosided = eps->twosided;
    1312:   PetscFunctionReturn(PETSC_SUCCESS);
    1313: }

    1315: /*@
    1316:    EPSSetTrueResidual - Specifies if the solver must compute the true residual
    1317:    explicitly or not.

    1319:    Logically Collective

    1321:    Input Parameters:
    1322: +  eps     - the linear eigensolver context
    1323: -  trueres - whether true residuals are required or not

    1325:    Options Database Key:
    1326: .  -eps_true_residual (true|false) - toggles the true residual

    1328:    Notes:
    1329:    If the user sets `trueres`=`PETSC_TRUE` then the solver explicitly computes
    1330:    the true residual for each eigenpair approximation, and uses it for
    1331:    convergence testing. Computing the residual is usually an expensive
    1332:    operation. Some solvers (e.g., Krylov solvers) can avoid this computation
    1333:    by using a cheap estimate of the residual norm, but this may sometimes
    1334:    give inaccurate results (especially if a spectral transform is being
    1335:    used). On the contrary, preconditioned eigensolvers (e.g., Davidson solvers)
    1336:    do rely on computing the true residual, so this option is irrelevant for them.

    1338:    Level: advanced

    1340: .seealso: [](ch:eps), `EPSGetTrueResidual()`
    1341: @*/
    1342: PetscErrorCode EPSSetTrueResidual(EPS eps,PetscBool trueres)
    1343: {
    1344:   PetscFunctionBegin;
    1347:   eps->trueres = trueres;
    1348:   PetscFunctionReturn(PETSC_SUCCESS);
    1349: }

    1351: /*@
    1352:    EPSGetTrueResidual - Returns the flag indicating whether true
    1353:    residuals must be computed explicitly or not.

    1355:    Not Collective

    1357:    Input Parameter:
    1358: .  eps - the linear eigensolver context

    1360:    Output Parameter:
    1361: .  trueres - the returned flag

    1363:    Level: advanced

    1365: .seealso: [](ch:eps), `EPSSetTrueResidual()`
    1366: @*/
    1367: PetscErrorCode EPSGetTrueResidual(EPS eps,PetscBool *trueres)
    1368: {
    1369:   PetscFunctionBegin;
    1371:   PetscAssertPointer(trueres,2);
    1372:   *trueres = eps->trueres;
    1373:   PetscFunctionReturn(PETSC_SUCCESS);
    1374: }

    1376: /*@
    1377:    EPSSetTrackAll - Specifies if the solver must compute the residual norm of all
    1378:    approximate eigenpairs or not.

    1380:    Logically Collective

    1382:    Input Parameters:
    1383: +  eps      - the linear eigensolver context
    1384: -  trackall - whether to compute all residuals or not

    1386:    Notes:
    1387:    If the user sets `trackall`=`PETSC_TRUE` then the solver computes (or estimates)
    1388:    the residual norm for each eigenpair approximation. Computing the residual is
    1389:    usually an expensive operation and solvers commonly compute only the residual
    1390:    associated to the first unconverged eigenpair.

    1392:    The option `-eps_monitor_all` automatically activates this option.

    1394:    Level: developer

    1396: .seealso: [](ch:eps), `EPSGetTrackAll()`
    1397: @*/
    1398: PetscErrorCode EPSSetTrackAll(EPS eps,PetscBool trackall)
    1399: {
    1400:   PetscFunctionBegin;
    1403:   eps->trackall = trackall;
    1404:   PetscFunctionReturn(PETSC_SUCCESS);
    1405: }

    1407: /*@
    1408:    EPSGetTrackAll - Returns the flag indicating whether all residual norms must
    1409:    be computed or not.

    1411:    Not Collective

    1413:    Input Parameter:
    1414: .  eps - the linear eigensolver context

    1416:    Output Parameter:
    1417: .  trackall - the returned flag

    1419:    Level: developer

    1421: .seealso: [](ch:eps), `EPSSetTrackAll()`
    1422: @*/
    1423: PetscErrorCode EPSGetTrackAll(EPS eps,PetscBool *trackall)
    1424: {
    1425:   PetscFunctionBegin;
    1427:   PetscAssertPointer(trackall,2);
    1428:   *trackall = eps->trackall;
    1429:   PetscFunctionReturn(PETSC_SUCCESS);
    1430: }

    1432: /*@
    1433:    EPSSetPurify - Disable eigenvector purification (which is enabled by default).

    1435:    Logically Collective

    1437:    Input Parameters:
    1438: +  eps    - the linear eigensolver context
    1439: -  purify - whether purification is done or not, use `PETSC_FALSE` to disable it

    1441:    Options Database Key:
    1442: .  -eps_purify (true|false) - toggles the purification flag

    1444:    Notes:
    1445:    By default, eigenvectors of generalized symmetric eigenproblems are purified
    1446:    in order to purge directions in the nullspace of matrix $B$. If the user knows
    1447:    that $B$ is non-singular, then purification can be safely deactivated and some
    1448:    computational cost is avoided (this is particularly important in interval computations).

    1450:    More details are given in section [](#sec:purif).

    1452:    Level: intermediate

    1454: .seealso: [](ch:eps), [](#sec:purif), `EPSGetPurify()`, `EPSSetInterval()`
    1455: @*/
    1456: PetscErrorCode EPSSetPurify(EPS eps,PetscBool purify)
    1457: {
    1458:   PetscFunctionBegin;
    1461:   if (purify!=eps->purify) {
    1462:     eps->purify = purify;
    1463:     eps->state  = EPS_STATE_INITIAL;
    1464:   }
    1465:   PetscFunctionReturn(PETSC_SUCCESS);
    1466: }

    1468: /*@
    1469:    EPSGetPurify - Returns the flag indicating whether purification is activated
    1470:    or not.

    1472:    Not Collective

    1474:    Input Parameter:
    1475: .  eps - the linear eigensolver context

    1477:    Output Parameter:
    1478: .  purify - the returned flag

    1480:    Level: intermediate

    1482: .seealso: [](ch:eps), `EPSSetPurify()`
    1483: @*/
    1484: PetscErrorCode EPSGetPurify(EPS eps,PetscBool *purify)
    1485: {
    1486:   PetscFunctionBegin;
    1488:   PetscAssertPointer(purify,2);
    1489:   *purify = eps->purify;
    1490:   PetscFunctionReturn(PETSC_SUCCESS);
    1491: }

    1493: /*@
    1494:    EPSSetOptionsPrefix - Sets the prefix used for searching for all
    1495:    `EPS` options in the database.

    1497:    Logically Collective

    1499:    Input Parameters:
    1500: +  eps    - the linear eigensolver context
    1501: -  prefix - the prefix string to prepend to all `EPS` option requests

    1503:    Notes:
    1504:    A hyphen (-) must NOT be given at the beginning of the prefix name.
    1505:    The first character of all runtime options is AUTOMATICALLY the
    1506:    hyphen.

    1508:    For example, to distinguish between the runtime options for two
    1509:    different `EPS` contexts, one could call
    1510: .vb
    1511:    EPSSetOptionsPrefix(eps1,"eig1_")
    1512:    EPSSetOptionsPrefix(eps2,"eig2_")
    1513: .ve

    1515:    Level: advanced

    1517: .seealso: [](ch:eps), `EPSAppendOptionsPrefix()`, `EPSGetOptionsPrefix()`
    1518: @*/
    1519: PetscErrorCode EPSSetOptionsPrefix(EPS eps,const char prefix[])
    1520: {
    1521:   PetscFunctionBegin;
    1523:   if (!eps->st) PetscCall(EPSGetST(eps,&eps->st));
    1524:   PetscCall(STSetOptionsPrefix(eps->st,prefix));
    1525:   if (!eps->V) PetscCall(EPSGetBV(eps,&eps->V));
    1526:   PetscCall(BVSetOptionsPrefix(eps->V,prefix));
    1527:   if (!eps->ds) PetscCall(EPSGetDS(eps,&eps->ds));
    1528:   PetscCall(DSSetOptionsPrefix(eps->ds,prefix));
    1529:   if (!eps->rg) PetscCall(EPSGetRG(eps,&eps->rg));
    1530:   PetscCall(RGSetOptionsPrefix(eps->rg,prefix));
    1531:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)eps,prefix));
    1532:   PetscFunctionReturn(PETSC_SUCCESS);
    1533: }

    1535: /*@
    1536:    EPSAppendOptionsPrefix - Appends to the prefix used for searching for all
    1537:    `EPS` options in the database.

    1539:    Logically Collective

    1541:    Input Parameters:
    1542: +  eps    - the linear eigensolver context
    1543: -  prefix - the prefix string to prepend to all `EPS` option requests

    1545:    Notes:
    1546:    A hyphen (-) must NOT be given at the beginning of the prefix name.
    1547:    The first character of all runtime options is AUTOMATICALLY the hyphen.

    1549:    Level: advanced

    1551: .seealso: [](ch:eps), `EPSSetOptionsPrefix()`, `EPSGetOptionsPrefix()`
    1552: @*/
    1553: PetscErrorCode EPSAppendOptionsPrefix(EPS eps,const char prefix[])
    1554: {
    1555:   PetscFunctionBegin;
    1557:   if (!eps->st) PetscCall(EPSGetST(eps,&eps->st));
    1558:   PetscCall(STAppendOptionsPrefix(eps->st,prefix));
    1559:   if (!eps->V) PetscCall(EPSGetBV(eps,&eps->V));
    1560:   PetscCall(BVAppendOptionsPrefix(eps->V,prefix));
    1561:   if (!eps->ds) PetscCall(EPSGetDS(eps,&eps->ds));
    1562:   PetscCall(DSAppendOptionsPrefix(eps->ds,prefix));
    1563:   if (!eps->rg) PetscCall(EPSGetRG(eps,&eps->rg));
    1564:   PetscCall(RGAppendOptionsPrefix(eps->rg,prefix));
    1565:   PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)eps,prefix));
    1566:   PetscFunctionReturn(PETSC_SUCCESS);
    1567: }

    1569: /*@
    1570:    EPSGetOptionsPrefix - Gets the prefix used for searching for all
    1571:    `EPS` options in the database.

    1573:    Not Collective

    1575:    Input Parameter:
    1576: .  eps - the linear eigensolver context

    1578:    Output Parameter:
    1579: .  prefix - pointer to the prefix string used is returned

    1581:    Level: advanced

    1583: .seealso: [](ch:eps), `EPSSetOptionsPrefix()`, `EPSAppendOptionsPrefix()`
    1584: @*/
    1585: PetscErrorCode EPSGetOptionsPrefix(EPS eps,const char *prefix[])
    1586: {
    1587:   PetscFunctionBegin;
    1589:   PetscAssertPointer(prefix,2);
    1590:   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)eps,prefix));
    1591:   PetscFunctionReturn(PETSC_SUCCESS);
    1592: }