Actual source code: pepopts.c
slepc-3.10.1 2018-10-23
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2018, 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>       /*I "slepcpep.h" I*/
     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 on PEP

     24:    Input Parameters:
     25: +  pep      - the polynomial eigensolver context
     26: .  name     - the monitor option name
     27: .  help     - message indicating what monitoring is done
     28: .  manual   - manual page for the monitor
     29: .  monitor  - the monitor function, whose context is a PetscViewerAndFormat
     30: -  trackall - whether this monitor tracks all eigenvalues or not

     32:    Level: developer

     34: .seealso: PEPMonitorSet(), PEPSetTrackAll(), PEPConvMonitorSetFromOptions()
     35: @*/
     36: PetscErrorCode PEPMonitorSetFromOptions(PEP pep,const char name[],const char help[],const char manual[],PetscErrorCode (*monitor)(PEP,PetscInt,PetscInt,PetscScalar*,PetscScalar*,PetscReal*,PetscInt,PetscViewerAndFormat*),PetscBool trackall)
     37: {
     38:   PetscErrorCode       ierr;
     39:   PetscBool            flg;
     40:   PetscViewer          viewer;
     41:   PetscViewerFormat    format;
     42:   PetscViewerAndFormat *vf;

     45:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)pep),((PetscObject)pep)->prefix,name,&viewer,&format,&flg);
     46:   if (flg) {
     47:     PetscViewerAndFormatCreate(viewer,format,&vf);
     48:     PetscObjectDereference((PetscObject)viewer);
     49:     PEPMonitorSet(pep,(PetscErrorCode (*)(PEP,PetscInt,PetscInt,PetscScalar*,PetscScalar*,PetscReal*,PetscInt,void*))monitor,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);
     50:     if (trackall) {
     51:       PEPSetTrackAll(pep,PETSC_TRUE);
     52:     }
     53:   }
     54:   return(0);
     55: }

     57: /*@C
     58:    PEPConvMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type
     59:    indicated by the user (for monitors that only show iteration numbers of convergence).

     61:    Collective on PEP

     63:    Input Parameters:
     64: +  pep      - the polynomial eigensolver context
     65: .  name     - the monitor option name
     66: .  help     - message indicating what monitoring is done
     67: .  manual   - manual page for the monitor
     68: -  monitor  - the monitor function, whose context is a SlepcConvMonitor

     70:    Level: developer

     72: .seealso: PEPMonitorSet(), PEPMonitorSetFromOptions()
     73: @*/
     74: PetscErrorCode PEPConvMonitorSetFromOptions(PEP pep,const char name[],const char help[],const char manual[],PetscErrorCode (*monitor)(PEP,PetscInt,PetscInt,PetscScalar*,PetscScalar*,PetscReal*,PetscInt,SlepcConvMonitor))
     75: {
     76:   PetscErrorCode    ierr;
     77:   PetscBool         flg;
     78:   PetscViewer       viewer;
     79:   PetscViewerFormat format;
     80:   SlepcConvMonitor  ctx;

     83:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)pep),((PetscObject)pep)->prefix,name,&viewer,&format,&flg);
     84:   if (flg) {
     85:     SlepcConvMonitorCreate(viewer,format,&ctx);
     86:     PetscObjectDereference((PetscObject)viewer);
     87:     PEPMonitorSet(pep,(PetscErrorCode (*)(PEP,PetscInt,PetscInt,PetscScalar*,PetscScalar*,PetscReal*,PetscInt,void*))monitor,ctx,(PetscErrorCode (*)(void**))SlepcConvMonitorDestroy);
     88:   }
     89:   return(0);
     90: }

     92: /*@
     93:    PEPSetFromOptions - Sets PEP options from the options database.
     94:    This routine must be called before PEPSetUp() if the user is to be
     95:    allowed to set the solver type.

     97:    Collective on PEP

     99:    Input Parameters:
    100: .  pep - the polynomial eigensolver context

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

    105:    Level: beginner
    106: @*/
    107: PetscErrorCode PEPSetFromOptions(PEP pep)
    108: {
    109:   PetscErrorCode  ierr;
    110:   char            type[256];
    111:   PetscBool       set,flg,flg1,flg2,flg3,flg4,flg5;
    112:   PetscReal       r,t,array[2]={0,0};
    113:   PetscScalar     s;
    114:   PetscInt        i,j,k;
    115:   PetscDrawLG     lg;
    116:   PEPScale        scale;
    117:   PEPRefine       refine;
    118:   PEPRefineScheme scheme;

    122:   PEPRegisterAll();
    123:   PetscObjectOptionsBegin((PetscObject)pep);
    124:     PetscOptionsFList("-pep_type","Polynomial eigensolver method","PEPSetType",PEPList,(char*)(((PetscObject)pep)->type_name?((PetscObject)pep)->type_name:PEPTOAR),type,256,&flg);
    125:     if (flg) {
    126:       PEPSetType(pep,type);
    127:     } else if (!((PetscObject)pep)->type_name) {
    128:       PEPSetType(pep,PEPTOAR);
    129:     }

    131:     PetscOptionsBoolGroupBegin("-pep_general","General polynomial eigenvalue problem","PEPSetProblemType",&flg);
    132:     if (flg) { PEPSetProblemType(pep,PEP_GENERAL); }
    133:     PetscOptionsBoolGroup("-pep_hermitian","Hermitian polynomial eigenvalue problem","PEPSetProblemType",&flg);
    134:     if (flg) { PEPSetProblemType(pep,PEP_HERMITIAN); }
    135:     PetscOptionsBoolGroup("-pep_hyperbolic","Hyperbolic polynomial eigenvalue problem","PEPSetProblemType",&flg);
    136:     if (flg) { PEPSetProblemType(pep,PEP_HYPERBOLIC); }
    137:     PetscOptionsBoolGroupEnd("-pep_gyroscopic","Gyroscopic polynomial eigenvalue problem","PEPSetProblemType",&flg);
    138:     if (flg) { PEPSetProblemType(pep,PEP_GYROSCOPIC); }

    140:     scale = pep->scale;
    141:     PetscOptionsEnum("-pep_scale","Scaling strategy","PEPSetScale",PEPScaleTypes,(PetscEnum)scale,(PetscEnum*)&scale,&flg1);
    142:     r = pep->sfactor;
    143:     PetscOptionsReal("-pep_scale_factor","Scale factor","PEPSetScale",pep->sfactor,&r,&flg2);
    144:     if (!flg2 && r==1.0) r = PETSC_DEFAULT;
    145:     j = pep->sits;
    146:     PetscOptionsInt("-pep_scale_its","Number of iterations in diagonal scaling","PEPSetScale",pep->sits,&j,&flg3);
    147:     t = pep->slambda;
    148:     PetscOptionsReal("-pep_scale_lambda","Estimate of eigenvalue (modulus) for diagonal scaling","PEPSetScale",pep->slambda,&t,&flg4);
    149:     if (flg1 || flg2 || flg3 || flg4) { PEPSetScale(pep,scale,r,NULL,NULL,j,t); }

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

    153:     refine = pep->refine;
    154:     PetscOptionsEnum("-pep_refine","Iterative refinement method","PEPSetRefine",PEPRefineTypes,(PetscEnum)refine,(PetscEnum*)&refine,&flg1);
    155:     i = pep->npart;
    156:     PetscOptionsInt("-pep_refine_partitions","Number of partitions of the communicator for iterative refinement","PEPSetRefine",pep->npart,&i,&flg2);
    157:     r = pep->rtol;
    158:     PetscOptionsReal("-pep_refine_tol","Tolerance for iterative refinement","PEPSetRefine",pep->rtol==PETSC_DEFAULT?SLEPC_DEFAULT_TOL/1000:pep->rtol,&r,&flg3);
    159:     j = pep->rits;
    160:     PetscOptionsInt("-pep_refine_its","Maximum number of iterations for iterative refinement","PEPSetRefine",pep->rits,&j,&flg4);
    161:     scheme = pep->scheme;
    162:     PetscOptionsEnum("-pep_refine_scheme","Scheme used for linear systems within iterative refinement","PEPSetRefine",PEPRefineSchemes,(PetscEnum)scheme,(PetscEnum*)&scheme,&flg5);
    163:     if (flg1 || flg2 || flg3 || flg4 || flg5) { PEPSetRefine(pep,refine,i,r,j,scheme); }

    165:     i = pep->max_it? pep->max_it: PETSC_DEFAULT;
    166:     PetscOptionsInt("-pep_max_it","Maximum number of iterations","PEPSetTolerances",pep->max_it,&i,&flg1);
    167:     r = pep->tol;
    168:     PetscOptionsReal("-pep_tol","Tolerance","PEPSetTolerances",pep->tol==PETSC_DEFAULT?SLEPC_DEFAULT_TOL:pep->tol,&r,&flg2);
    169:     if (flg1 || flg2) { PEPSetTolerances(pep,r,i); }

    171:     PetscOptionsBoolGroupBegin("-pep_conv_rel","Relative error convergence test","PEPSetConvergenceTest",&flg);
    172:     if (flg) { PEPSetConvergenceTest(pep,PEP_CONV_REL); }
    173:     PetscOptionsBoolGroup("-pep_conv_norm","Convergence test relative to the matrix norms","PEPSetConvergenceTest",&flg);
    174:     if (flg) { PEPSetConvergenceTest(pep,PEP_CONV_NORM); }
    175:     PetscOptionsBoolGroup("-pep_conv_abs","Absolute error convergence test","PEPSetConvergenceTest",&flg);
    176:     if (flg) { PEPSetConvergenceTest(pep,PEP_CONV_ABS); }
    177:     PetscOptionsBoolGroupEnd("-pep_conv_user","User-defined convergence test","PEPSetConvergenceTest",&flg);
    178:     if (flg) { PEPSetConvergenceTest(pep,PEP_CONV_USER); }

    180:     PetscOptionsBoolGroupBegin("-pep_stop_basic","Stop iteration if all eigenvalues converged or max_it reached","PEPSetStoppingTest",&flg);
    181:     if (flg) { PEPSetStoppingTest(pep,PEP_STOP_BASIC); }
    182:     PetscOptionsBoolGroupEnd("-pep_stop_user","User-defined stopping test","PEPSetStoppingTest",&flg);
    183:     if (flg) { PEPSetStoppingTest(pep,PEP_STOP_USER); }

    185:     i = pep->nev;
    186:     PetscOptionsInt("-pep_nev","Number of eigenvalues to compute","PEPSetDimensions",pep->nev,&i,&flg1);
    187:     j = pep->ncv? pep->ncv: PETSC_DEFAULT;
    188:     PetscOptionsInt("-pep_ncv","Number of basis vectors","PEPSetDimensions",pep->ncv,&j,&flg2);
    189:     k = pep->mpd? pep->mpd: PETSC_DEFAULT;
    190:     PetscOptionsInt("-pep_mpd","Maximum dimension of projected problem","PEPSetDimensions",pep->mpd,&k,&flg3);
    191:     if (flg1 || flg2 || flg3) { PEPSetDimensions(pep,i,j,k); }

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

    195:     PetscOptionsBoolGroupBegin("-pep_largest_magnitude","Compute largest eigenvalues in magnitude","PEPSetWhichEigenpairs",&flg);
    196:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_LARGEST_MAGNITUDE); }
    197:     PetscOptionsBoolGroup("-pep_smallest_magnitude","Compute smallest eigenvalues in magnitude","PEPSetWhichEigenpairs",&flg);
    198:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_SMALLEST_MAGNITUDE); }
    199:     PetscOptionsBoolGroup("-pep_largest_real","Compute eigenvalues with largest real parts","PEPSetWhichEigenpairs",&flg);
    200:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_LARGEST_REAL); }
    201:     PetscOptionsBoolGroup("-pep_smallest_real","Compute eigenvalues with smallest real parts","PEPSetWhichEigenpairs",&flg);
    202:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_SMALLEST_REAL); }
    203:     PetscOptionsBoolGroup("-pep_largest_imaginary","Compute eigenvalues with largest imaginary parts","PEPSetWhichEigenpairs",&flg);
    204:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_LARGEST_IMAGINARY); }
    205:     PetscOptionsBoolGroup("-pep_smallest_imaginary","Compute eigenvalues with smallest imaginary parts","PEPSetWhichEigenpairs",&flg);
    206:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_SMALLEST_IMAGINARY); }
    207:     PetscOptionsBoolGroup("-pep_target_magnitude","Compute eigenvalues closest to target","PEPSetWhichEigenpairs",&flg);
    208:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_TARGET_MAGNITUDE); }
    209:     PetscOptionsBoolGroup("-pep_target_real","Compute eigenvalues with real parts closest to target","PEPSetWhichEigenpairs",&flg);
    210:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_TARGET_REAL); }
    211:     PetscOptionsBoolGroupEnd("-pep_target_imaginary","Compute eigenvalues with imaginary parts closest to target","PEPSetWhichEigenpairs",&flg);
    212:     if (flg) { PEPSetWhichEigenpairs(pep,PEP_TARGET_IMAGINARY); }

    214:     PetscOptionsScalar("-pep_target","Value of the target","PEPSetTarget",pep->target,&s,&flg);
    215:     if (flg) {
    216:       if (pep->which!=PEP_TARGET_REAL && pep->which!=PEP_TARGET_IMAGINARY) {
    217:         PEPSetWhichEigenpairs(pep,PEP_TARGET_MAGNITUDE);
    218:       }
    219:       PEPSetTarget(pep,s);
    220:     }

    222:     k = 2;
    223:     PetscOptionsRealArray("-pep_interval","Computational interval (two real values separated with a comma without spaces)","PEPSetInterval",array,&k,&flg);
    224:     if (flg) {
    225:       if (k<2) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_SIZ,"Must pass two values in -pep_interval (comma-separated without spaces)");
    226:       PEPSetWhichEigenpairs(pep,PEP_ALL);
    227:       PEPSetInterval(pep,array[0],array[1]);
    228:     }

    230:     /* -----------------------------------------------------------------------*/
    231:     /*
    232:       Cancels all monitors hardwired into code before call to PEPSetFromOptions()
    233:     */
    234:     PetscOptionsBool("-pep_monitor_cancel","Remove any hardwired monitor routines","PEPMonitorCancel",PETSC_FALSE,&flg,&set);
    235:     if (set && flg) {
    236:       PEPMonitorCancel(pep);
    237:     }
    238:     /*
    239:       Text monitors
    240:     */
    241:     PEPMonitorSetFromOptions(pep,"-pep_monitor","Monitor first unconverged approximate eigenvalue and error estimate","PEPMonitorFirst",PEPMonitorFirst,PETSC_FALSE);
    242:     PEPConvMonitorSetFromOptions(pep,"-pep_monitor_conv","Monitor approximate eigenvalues and error estimates as they converge","PEPMonitorConverged",PEPMonitorConverged);
    243:     PEPMonitorSetFromOptions(pep,"-pep_monitor_all","Monitor approximate eigenvalues and error estimates","PEPMonitorAll",PEPMonitorAll,PETSC_TRUE);
    244:     /*
    245:       Line graph monitors
    246:     */
    247:     PetscOptionsBool("-pep_monitor_lg","Monitor first unconverged approximate error estimate graphically","PEPMonitorSet",PETSC_FALSE,&flg,&set);
    248:     if (set && flg) {
    249:       PEPMonitorLGCreate(PetscObjectComm((PetscObject)pep),NULL,"Error estimates",PETSC_DECIDE,PETSC_DECIDE,300,300,&lg);
    250:       PEPMonitorSet(pep,PEPMonitorLG,lg,(PetscErrorCode (*)(void**))PetscDrawLGDestroy);
    251:     }
    252:     PetscOptionsBool("-pep_monitor_lg_all","Monitor error estimates graphically","PEPMonitorSet",PETSC_FALSE,&flg,&set);
    253:     if (set && flg) {
    254:       PEPMonitorLGCreate(PetscObjectComm((PetscObject)pep),NULL,"Error estimates",PETSC_DECIDE,PETSC_DECIDE,300,300,&lg);
    255:       PEPMonitorSet(pep,PEPMonitorLGAll,lg,(PetscErrorCode (*)(void**))PetscDrawLGDestroy);
    256:       PEPSetTrackAll(pep,PETSC_TRUE);
    257:     }

    259:     /* -----------------------------------------------------------------------*/
    260:     PetscOptionsName("-pep_view","Print detailed information on solver used","PEPView",NULL);
    261:     PetscOptionsName("-pep_view_vectors","View computed eigenvectors","PEPVectorsView",NULL);
    262:     PetscOptionsName("-pep_view_values","View computed eigenvalues","PEPValuesView",NULL);
    263:     PetscOptionsName("-pep_converged_reason","Print reason for convergence, and number of iterations","PEPReasonView",NULL);
    264:     PetscOptionsName("-pep_error_absolute","Print absolute errors of each eigenpair","PEPErrorView",NULL);
    265:     PetscOptionsName("-pep_error_relative","Print relative errors of each eigenpair","PEPErrorView",NULL);
    266:     PetscOptionsName("-pep_error_backward","Print backward errors of each eigenpair","PEPErrorView",NULL);

    268:     if (pep->ops->setfromoptions) {
    269:       (*pep->ops->setfromoptions)(PetscOptionsObject,pep);
    270:     }
    271:     PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)pep);
    272:   PetscOptionsEnd();

    274:   if (!pep->V) { PEPGetBV(pep,&pep->V); }
    275:   BVSetFromOptions(pep->V);
    276:   if (!pep->rg) { PEPGetRG(pep,&pep->rg); }
    277:   RGSetFromOptions(pep->rg);
    278:   if (!pep->ds) { PEPGetDS(pep,&pep->ds); }
    279:   DSSetFromOptions(pep->ds);
    280:   if (!pep->st) { PEPGetST(pep,&pep->st); }
    281:   PEPSetDefaultST(pep);
    282:   STSetFromOptions(pep->st);
    283:   if (!pep->refineksp) { PEPRefineGetKSP(pep,&pep->refineksp); }
    284:   KSPSetFromOptions(pep->refineksp);
    285:   return(0);
    286: }

    288: /*@C
    289:    PEPGetTolerances - Gets the tolerance and maximum iteration count used
    290:    by the PEP convergence tests.

    292:    Not Collective

    294:    Input Parameter:
    295: .  pep - the polynomial eigensolver context

    297:    Output Parameters:
    298: +  tol - the convergence tolerance
    299: -  maxits - maximum number of iterations

    301:    Notes:
    302:    The user can specify NULL for any parameter that is not needed.

    304:    Level: intermediate

    306: .seealso: PEPSetTolerances()
    307: @*/
    308: PetscErrorCode PEPGetTolerances(PEP pep,PetscReal *tol,PetscInt *maxits)
    309: {
    312:   if (tol)    *tol    = pep->tol;
    313:   if (maxits) *maxits = pep->max_it;
    314:   return(0);
    315: }

    317: /*@
    318:    PEPSetTolerances - Sets the tolerance and maximum iteration count used
    319:    by the PEP convergence tests.

    321:    Logically Collective on PEP

    323:    Input Parameters:
    324: +  pep - the polynomial eigensolver context
    325: .  tol - the convergence tolerance
    326: -  maxits - maximum number of iterations to use

    328:    Options Database Keys:
    329: +  -pep_tol <tol> - Sets the convergence tolerance
    330: -  -pep_max_it <maxits> - Sets the maximum number of iterations allowed

    332:    Notes:
    333:    Use PETSC_DEFAULT for either argument to assign a reasonably good value.

    335:    Level: intermediate

    337: .seealso: PEPGetTolerances()
    338: @*/
    339: PetscErrorCode PEPSetTolerances(PEP pep,PetscReal tol,PetscInt maxits)
    340: {
    345:   if (tol == PETSC_DEFAULT) {
    346:     pep->tol   = PETSC_DEFAULT;
    347:     pep->state = PEP_STATE_INITIAL;
    348:   } else {
    349:     if (tol <= 0.0) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of tol. Must be > 0");
    350:     pep->tol = tol;
    351:   }
    352:   if (maxits == PETSC_DEFAULT || maxits == PETSC_DECIDE) {
    353:     pep->max_it = 0;
    354:     pep->state  = PEP_STATE_INITIAL;
    355:   } else {
    356:     if (maxits <= 0) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of maxits. Must be > 0");
    357:     pep->max_it = maxits;
    358:   }
    359:   return(0);
    360: }

    362: /*@C
    363:    PEPGetDimensions - Gets the number of eigenvalues to compute
    364:    and the dimension of the subspace.

    366:    Not Collective

    368:    Input Parameter:
    369: .  pep - the polynomial eigensolver context

    371:    Output Parameters:
    372: +  nev - number of eigenvalues to compute
    373: .  ncv - the maximum dimension of the subspace to be used by the solver
    374: -  mpd - the maximum dimension allowed for the projected problem

    376:    Notes:
    377:    The user can specify NULL for any parameter that is not needed.

    379:    Level: intermediate

    381: .seealso: PEPSetDimensions()
    382: @*/
    383: PetscErrorCode PEPGetDimensions(PEP pep,PetscInt *nev,PetscInt *ncv,PetscInt *mpd)
    384: {
    387:   if (nev) *nev = pep->nev;
    388:   if (ncv) *ncv = pep->ncv;
    389:   if (mpd) *mpd = pep->mpd;
    390:   return(0);
    391: }

    393: /*@
    394:    PEPSetDimensions - Sets the number of eigenvalues to compute
    395:    and the dimension of the subspace.

    397:    Logically Collective on PEP

    399:    Input Parameters:
    400: +  pep - the polynomial eigensolver context
    401: .  nev - number of eigenvalues to compute
    402: .  ncv - the maximum dimension of the subspace to be used by the solver
    403: -  mpd - the maximum dimension allowed for the projected problem

    405:    Options Database Keys:
    406: +  -pep_nev <nev> - Sets the number of eigenvalues
    407: .  -pep_ncv <ncv> - Sets the dimension of the subspace
    408: -  -pep_mpd <mpd> - Sets the maximum projected dimension

    410:    Notes:
    411:    Use PETSC_DEFAULT for ncv and mpd to assign a reasonably good value, which is
    412:    dependent on the solution method.

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

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

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

    426:    Level: intermediate

    428: .seealso: PEPGetDimensions(), PEPSetInterval(), PEPSTOARSetDimensions()
    429: @*/
    430: PetscErrorCode PEPSetDimensions(PEP pep,PetscInt nev,PetscInt ncv,PetscInt mpd)
    431: {
    437:   if (nev<1) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of nev. Must be > 0");
    438:   pep->nev = nev;
    439:   if (ncv == PETSC_DECIDE || ncv == PETSC_DEFAULT) {
    440:     pep->ncv = 0;
    441:   } else {
    442:     if (ncv<1) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of ncv. Must be > 0");
    443:     pep->ncv = ncv;
    444:   }
    445:   if (mpd == PETSC_DECIDE || mpd == PETSC_DEFAULT) {
    446:     pep->mpd = 0;
    447:   } else {
    448:     if (mpd<1) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of mpd. Must be > 0");
    449:     pep->mpd = mpd;
    450:   }
    451:   pep->state = PEP_STATE_INITIAL;
    452:   return(0);
    453: }

    455: /*@
    456:    PEPSetWhichEigenpairs - Specifies which portion of the spectrum is
    457:    to be sought.

    459:    Logically Collective on PEP

    461:    Input Parameters:
    462: +  pep   - eigensolver context obtained from PEPCreate()
    463: -  which - the portion of the spectrum to be sought

    465:    Possible values:
    466:    The parameter 'which' can have one of these values

    468: +     PEP_LARGEST_MAGNITUDE - largest eigenvalues in magnitude (default)
    469: .     PEP_SMALLEST_MAGNITUDE - smallest eigenvalues in magnitude
    470: .     PEP_LARGEST_REAL - largest real parts
    471: .     PEP_SMALLEST_REAL - smallest real parts
    472: .     PEP_LARGEST_IMAGINARY - largest imaginary parts
    473: .     PEP_SMALLEST_IMAGINARY - smallest imaginary parts
    474: .     PEP_TARGET_MAGNITUDE - eigenvalues closest to the target (in magnitude)
    475: .     PEP_TARGET_REAL - eigenvalues with real part closest to target
    476: .     PEP_TARGET_IMAGINARY - eigenvalues with imaginary part closest to target
    477: .     PEP_ALL - all eigenvalues contained in a given interval
    478: -     PEP_WHICH_USER - user defined ordering set with PEPSetEigenvalueComparison()

    480:    Options Database Keys:
    481: +   -pep_largest_magnitude - Sets largest eigenvalues in magnitude
    482: .   -pep_smallest_magnitude - Sets smallest eigenvalues in magnitude
    483: .   -pep_largest_real - Sets largest real parts
    484: .   -pep_smallest_real - Sets smallest real parts
    485: .   -pep_largest_imaginary - Sets largest imaginary parts
    486: .   -pep_smallest_imaginary - Sets smallest imaginary parts
    487: .   -pep_target_magnitude - Sets eigenvalues closest to target
    488: .   -pep_target_real - Sets real parts closest to target
    489: .   -pep_target_imaginary - Sets imaginary parts closest to target
    490: -   -pep_all - Sets all eigenvalues in an interval

    492:    Notes:
    493:    Not all eigensolvers implemented in PEP account for all the possible values
    494:    stated above. If SLEPc is compiled for real numbers PEP_LARGEST_IMAGINARY
    495:    and PEP_SMALLEST_IMAGINARY use the absolute value of the imaginary part
    496:    for eigenvalue selection.

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

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

    503:    PEP_ALL is intended for use in combination with an interval (see
    504:    PEPSetInterval()), when all eigenvalues within the interval are requested.
    505:    In that case, the number of eigenvalues is unknown, so the nev parameter
    506:    has a different sense, see PEPSetDimensions().

    508:    Level: intermediate

    510: .seealso: PEPGetWhichEigenpairs(), PEPSetTarget(), PEPSetInterval(),
    511:           PEPSetDimensions(), PEPSetEigenvalueComparison(), PEPWhich
    512: @*/
    513: PetscErrorCode PEPSetWhichEigenpairs(PEP pep,PEPWhich which)
    514: {
    518:   switch (which) {
    519:     case PEP_LARGEST_MAGNITUDE:
    520:     case PEP_SMALLEST_MAGNITUDE:
    521:     case PEP_LARGEST_REAL:
    522:     case PEP_SMALLEST_REAL:
    523:     case PEP_LARGEST_IMAGINARY:
    524:     case PEP_SMALLEST_IMAGINARY:
    525:     case PEP_TARGET_MAGNITUDE:
    526:     case PEP_TARGET_REAL:
    527: #if defined(PETSC_USE_COMPLEX)
    528:     case PEP_TARGET_IMAGINARY:
    529: #endif
    530:     case PEP_ALL:
    531:     case PEP_WHICH_USER:
    532:       if (pep->which != which) {
    533:         pep->state = PEP_STATE_INITIAL;
    534:         pep->which = which;
    535:       }
    536:       break;
    537:     default:
    538:       SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'which' value");
    539:   }
    540:   return(0);
    541: }

    543: /*@
    544:     PEPGetWhichEigenpairs - Returns which portion of the spectrum is to be
    545:     sought.

    547:     Not Collective

    549:     Input Parameter:
    550: .   pep - eigensolver context obtained from PEPCreate()

    552:     Output Parameter:
    553: .   which - the portion of the spectrum to be sought

    555:     Notes:
    556:     See PEPSetWhichEigenpairs() for possible values of 'which'.

    558:     Level: intermediate

    560: .seealso: PEPSetWhichEigenpairs(), PEPWhich
    561: @*/
    562: PetscErrorCode PEPGetWhichEigenpairs(PEP pep,PEPWhich *which)
    563: {
    567:   *which = pep->which;
    568:   return(0);
    569: }

    571: /*@C
    572:    PEPSetEigenvalueComparison - Specifies the eigenvalue comparison function
    573:    when PEPSetWhichEigenpairs() is set to PEP_WHICH_USER.

    575:    Logically Collective on PEP

    577:    Input Parameters:
    578: +  pep  - eigensolver context obtained from PEPCreate()
    579: .  func - a pointer to the comparison function
    580: -  ctx  - a context pointer (the last parameter to the comparison function)

    582:    Calling Sequence of func:
    583: $   func(PetscScalar ar,PetscScalar ai,PetscScalar br,PetscScalar bi,PetscInt *res,void *ctx)

    585: +   ar     - real part of the 1st eigenvalue
    586: .   ai     - imaginary part of the 1st eigenvalue
    587: .   br     - real part of the 2nd eigenvalue
    588: .   bi     - imaginary part of the 2nd eigenvalue
    589: .   res    - result of comparison
    590: -   ctx    - optional context, as set by PEPSetEigenvalueComparison()

    592:    Note:
    593:    The returning parameter 'res' can be
    594: +  negative - if the 1st eigenvalue is preferred to the 2st one
    595: .  zero     - if both eigenvalues are equally preferred
    596: -  positive - if the 2st eigenvalue is preferred to the 1st one

    598:    Level: advanced

    600: .seealso: PEPSetWhichEigenpairs(), PEPWhich
    601: @*/
    602: PetscErrorCode PEPSetEigenvalueComparison(PEP pep,PetscErrorCode (*func)(PetscScalar,PetscScalar,PetscScalar,PetscScalar,PetscInt*,void*),void* ctx)
    603: {
    606:   pep->sc->comparison    = func;
    607:   pep->sc->comparisonctx = ctx;
    608:   pep->which             = PEP_WHICH_USER;
    609:   return(0);
    610: }

    612: /*@
    613:    PEPSetProblemType - Specifies the type of the polynomial eigenvalue problem.

    615:    Logically Collective on PEP

    617:    Input Parameters:
    618: +  pep  - the polynomial eigensolver context
    619: -  type - a known type of polynomial eigenvalue problem

    621:    Options Database Keys:
    622: +  -pep_general - general problem with no particular structure
    623: .  -pep_hermitian - problem whose coefficient matrices are Hermitian
    624: .  -pep_hyperbolic - Hermitian problem that satisfies the definition of hyperbolic
    625: -  -pep_gyroscopic - problem with Hamiltonian structure

    627:    Notes:
    628:    Allowed values for the problem type are: general (PEP_GENERAL), Hermitian
    629:    (PEP_HERMITIAN), hyperbolic (PEP_HYPERBOLIC), and gyroscopic (PEP_GYROSCOPIC).

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

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

    640:    Level: intermediate

    642: .seealso: PEPSetOperators(), PEPSetType(), PEPGetProblemType(), PEPProblemType
    643: @*/
    644: PetscErrorCode PEPSetProblemType(PEP pep,PEPProblemType type)
    645: {
    649:   if (type!=PEP_GENERAL && type!=PEP_HERMITIAN && type!=PEP_HYPERBOLIC && type!=PEP_GYROSCOPIC) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_WRONG,"Unknown eigenvalue problem type");
    650:   if (type != pep->problem_type) {
    651:     pep->problem_type = type;
    652:     pep->state = PEP_STATE_INITIAL;
    653:   }
    654:   return(0);
    655: }

    657: /*@
    658:    PEPGetProblemType - Gets the problem type from the PEP object.

    660:    Not Collective

    662:    Input Parameter:
    663: .  pep - the polynomial eigensolver context

    665:    Output Parameter:
    666: .  type - the problem type

    668:    Level: intermediate

    670: .seealso: PEPSetProblemType(), PEPProblemType
    671: @*/
    672: PetscErrorCode PEPGetProblemType(PEP pep,PEPProblemType *type)
    673: {
    677:   *type = pep->problem_type;
    678:   return(0);
    679: }

    681: /*@
    682:    PEPSetBasis - Specifies the type of polynomial basis used to describe the
    683:    polynomial eigenvalue problem.

    685:    Logically Collective on PEP

    687:    Input Parameters:
    688: +  pep   - the polynomial eigensolver context
    689: -  basis - the type of polynomial basis

    691:    Options Database Key:
    692: .  -pep_basis <basis> - Select the basis type

    694:    Notes:
    695:    By default, the coefficient matrices passed via PEPSetOperators() are
    696:    expressed in the monomial basis, i.e.
    697:    P(lambda) = A_0 + lambda*A_1 + lambda^2*A_2 + ... + lambda^d*A_d.
    698:    Other polynomial bases may have better numerical behaviour, but the user
    699:    must then pass the coefficient matrices accordingly.

    701:    Level: intermediate

    703: .seealso: PEPSetOperators(), PEPGetBasis(), PEPBasis
    704: @*/
    705: PetscErrorCode PEPSetBasis(PEP pep,PEPBasis basis)
    706: {
    710:   pep->basis = basis;
    711:   return(0);
    712: }

    714: /*@
    715:    PEPGetBasis - Gets the type of polynomial basis from the PEP object.

    717:    Not Collective

    719:    Input Parameter:
    720: .  pep - the polynomial eigensolver context

    722:    Output Parameter:
    723: .  basis - the polynomial basis

    725:    Level: intermediate

    727: .seealso: PEPSetBasis(), PEPBasis
    728: @*/
    729: PetscErrorCode PEPGetBasis(PEP pep,PEPBasis *basis)
    730: {
    734:   *basis = pep->basis;
    735:   return(0);
    736: }

    738: /*@
    739:    PEPSetTrackAll - Specifies if the solver must compute the residual of all
    740:    approximate eigenpairs or not.

    742:    Logically Collective on PEP

    744:    Input Parameters:
    745: +  pep      - the eigensolver context
    746: -  trackall - whether compute all residuals or not

    748:    Notes:
    749:    If the user sets trackall=PETSC_TRUE then the solver explicitly computes
    750:    the residual for each eigenpair approximation. Computing the residual is
    751:    usually an expensive operation and solvers commonly compute the associated
    752:    residual to the first unconverged eigenpair.
    753:    The options '-pep_monitor_all' and '-pep_monitor_lg_all' automatically
    754:    activate this option.

    756:    Level: developer

    758: .seealso: PEPGetTrackAll()
    759: @*/
    760: PetscErrorCode PEPSetTrackAll(PEP pep,PetscBool trackall)
    761: {
    765:   pep->trackall = trackall;
    766:   return(0);
    767: }

    769: /*@
    770:    PEPGetTrackAll - Returns the flag indicating whether all residual norms must
    771:    be computed or not.

    773:    Not Collective

    775:    Input Parameter:
    776: .  pep - the eigensolver context

    778:    Output Parameter:
    779: .  trackall - the returned flag

    781:    Level: developer

    783: .seealso: PEPSetTrackAll()
    784: @*/
    785: PetscErrorCode PEPGetTrackAll(PEP pep,PetscBool *trackall)
    786: {
    790:   *trackall = pep->trackall;
    791:   return(0);
    792: }

    794: /*@C
    795:    PEPSetConvergenceTestFunction - Sets a function to compute the error estimate
    796:    used in the convergence test.

    798:    Logically Collective on PEP

    800:    Input Parameters:
    801: +  pep     - eigensolver context obtained from PEPCreate()
    802: .  func    - a pointer to the convergence test function
    803: .  ctx     - context for private data for the convergence routine (may be null)
    804: -  destroy - a routine for destroying the context (may be null)

    806:    Calling Sequence of func:
    807: $   func(PEP pep,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)

    809: +   pep    - eigensolver context obtained from PEPCreate()
    810: .   eigr   - real part of the eigenvalue
    811: .   eigi   - imaginary part of the eigenvalue
    812: .   res    - residual norm associated to the eigenpair
    813: .   errest - (output) computed error estimate
    814: -   ctx    - optional context, as set by PEPSetConvergenceTestFunction()

    816:    Note:
    817:    If the error estimate returned by the convergence test function is less than
    818:    the tolerance, then the eigenvalue is accepted as converged.

    820:    Level: advanced

    822: .seealso: PEPSetConvergenceTest(), PEPSetTolerances()
    823: @*/
    824: PetscErrorCode PEPSetConvergenceTestFunction(PEP pep,PetscErrorCode (*func)(PEP,PetscScalar,PetscScalar,PetscReal,PetscReal*,void*),void* ctx,PetscErrorCode (*destroy)(void*))
    825: {

    830:   if (pep->convergeddestroy) {
    831:     (*pep->convergeddestroy)(pep->convergedctx);
    832:   }
    833:   pep->convergeduser    = func;
    834:   pep->convergeddestroy = destroy;
    835:   pep->convergedctx     = ctx;
    836:   if (func == PEPConvergedRelative) pep->conv = PEP_CONV_REL;
    837:   else if (func == PEPConvergedNorm) pep->conv = PEP_CONV_NORM;
    838:   else if (func == PEPConvergedAbsolute) pep->conv = PEP_CONV_ABS;
    839:   else {
    840:     pep->conv      = PEP_CONV_USER;
    841:     pep->converged = pep->convergeduser;
    842:   }
    843:   return(0);
    844: }

    846: /*@
    847:    PEPSetConvergenceTest - Specifies how to compute the error estimate
    848:    used in the convergence test.

    850:    Logically Collective on PEP

    852:    Input Parameters:
    853: +  pep  - eigensolver context obtained from PEPCreate()
    854: -  conv - the type of convergence test

    856:    Options Database Keys:
    857: +  -pep_conv_abs    - Sets the absolute convergence test
    858: .  -pep_conv_rel    - Sets the convergence test relative to the eigenvalue
    859: .  -pep_conv_norm   - Sets the convergence test relative to the matrix norms
    860: -  -pep_conv_user   - Selects the user-defined convergence test

    862:    Note:
    863:    The parameter 'conv' can have one of these values
    864: +     PEP_CONV_ABS    - absolute error ||r||
    865: .     PEP_CONV_REL    - error relative to the eigenvalue l, ||r||/|l|
    866: .     PEP_CONV_NORM   - error relative matrix norms, ||r||/sum_i(l^i*||A_i||)
    867: -     PEP_CONV_USER   - function set by PEPSetConvergenceTestFunction()

    869:    Level: intermediate

    871: .seealso: PEPGetConvergenceTest(), PEPSetConvergenceTestFunction(), PEPSetStoppingTest(), PEPConv
    872: @*/
    873: PetscErrorCode PEPSetConvergenceTest(PEP pep,PEPConv conv)
    874: {
    878:   switch (conv) {
    879:     case PEP_CONV_ABS:  pep->converged = PEPConvergedAbsolute; break;
    880:     case PEP_CONV_REL:  pep->converged = PEPConvergedRelative; break;
    881:     case PEP_CONV_NORM: pep->converged = PEPConvergedNorm; break;
    882:     case PEP_CONV_USER:
    883:       if (!pep->convergeduser) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ORDER,"Must call PEPSetConvergenceTestFunction() first");
    884:       pep->converged = pep->convergeduser;
    885:       break;
    886:     default:
    887:       SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'conv' value");
    888:   }
    889:   pep->conv = conv;
    890:   return(0);
    891: }

    893: /*@
    894:    PEPGetConvergenceTest - Gets the method used to compute the error estimate
    895:    used in the convergence test.

    897:    Not Collective

    899:    Input Parameters:
    900: .  pep   - eigensolver context obtained from PEPCreate()

    902:    Output Parameters:
    903: .  conv  - the type of convergence test

    905:    Level: intermediate

    907: .seealso: PEPSetConvergenceTest(), PEPConv
    908: @*/
    909: PetscErrorCode PEPGetConvergenceTest(PEP pep,PEPConv *conv)
    910: {
    914:   *conv = pep->conv;
    915:   return(0);
    916: }

    918: /*@C
    919:    PEPSetStoppingTestFunction - Sets a function to decide when to stop the outer
    920:    iteration of the eigensolver.

    922:    Logically Collective on PEP

    924:    Input Parameters:
    925: +  pep     - eigensolver context obtained from PEPCreate()
    926: .  func    - pointer to the stopping test function
    927: .  ctx     - context for private data for the stopping routine (may be null)
    928: -  destroy - a routine for destroying the context (may be null)

    930:    Calling Sequence of func:
    931: $   func(PEP pep,PetscInt its,PetscInt max_it,PetscInt nconv,PetscInt nev,PEPConvergedReason *reason,void *ctx)

    933: +   pep    - eigensolver context obtained from PEPCreate()
    934: .   its    - current number of iterations
    935: .   max_it - maximum number of iterations
    936: .   nconv  - number of currently converged eigenpairs
    937: .   nev    - number of requested eigenpairs
    938: .   reason - (output) result of the stopping test
    939: -   ctx    - optional context, as set by PEPSetStoppingTestFunction()

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

    947:    Level: advanced

    949: .seealso: PEPSetStoppingTest(), PEPStoppingBasic()
    950: @*/
    951: PetscErrorCode PEPSetStoppingTestFunction(PEP pep,PetscErrorCode (*func)(PEP,PetscInt,PetscInt,PetscInt,PetscInt,PEPConvergedReason*,void*),void* ctx,PetscErrorCode (*destroy)(void*))
    952: {

    957:   if (pep->stoppingdestroy) {
    958:     (*pep->stoppingdestroy)(pep->stoppingctx);
    959:   }
    960:   pep->stoppinguser    = func;
    961:   pep->stoppingdestroy = destroy;
    962:   pep->stoppingctx     = ctx;
    963:   if (func == PEPStoppingBasic) pep->stop = PEP_STOP_BASIC;
    964:   else {
    965:     pep->stop     = PEP_STOP_USER;
    966:     pep->stopping = pep->stoppinguser;
    967:   }
    968:   return(0);
    969: }

    971: /*@
    972:    PEPSetStoppingTest - Specifies how to decide the termination of the outer
    973:    loop of the eigensolver.

    975:    Logically Collective on PEP

    977:    Input Parameters:
    978: +  pep  - eigensolver context obtained from PEPCreate()
    979: -  stop - the type of stopping test

    981:    Options Database Keys:
    982: +  -pep_stop_basic - Sets the default stopping test
    983: -  -pep_stop_user  - Selects the user-defined stopping test

    985:    Note:
    986:    The parameter 'stop' can have one of these values
    987: +     PEP_STOP_BASIC - default stopping test
    988: -     PEP_STOP_USER  - function set by PEPSetStoppingTestFunction()

    990:    Level: advanced

    992: .seealso: PEPGetStoppingTest(), PEPSetStoppingTestFunction(), PEPSetConvergenceTest(), PEPStop
    993: @*/
    994: PetscErrorCode PEPSetStoppingTest(PEP pep,PEPStop stop)
    995: {
    999:   switch (stop) {
    1000:     case PEP_STOP_BASIC: pep->stopping = PEPStoppingBasic; break;
    1001:     case PEP_STOP_USER:
    1002:       if (!pep->stoppinguser) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ORDER,"Must call PEPSetStoppingTestFunction() first");
    1003:       pep->stopping = pep->stoppinguser;
    1004:       break;
    1005:     default:
    1006:       SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Invalid 'stop' value");
    1007:   }
    1008:   pep->stop = stop;
    1009:   return(0);
    1010: }

    1012: /*@
    1013:    PEPGetStoppingTest - Gets the method used to decide the termination of the outer
    1014:    loop of the eigensolver.

    1016:    Not Collective

    1018:    Input Parameters:
    1019: .  pep   - eigensolver context obtained from PEPCreate()

    1021:    Output Parameters:
    1022: .  stop  - the type of stopping test

    1024:    Level: advanced

    1026: .seealso: PEPSetStoppingTest(), PEPStop
    1027: @*/
    1028: PetscErrorCode PEPGetStoppingTest(PEP pep,PEPStop *stop)
    1029: {
    1033:   *stop = pep->stop;
    1034:   return(0);
    1035: }

    1037: /*@
    1038:    PEPSetScale - Specifies the scaling strategy to be used.

    1040:    Logically Collective on PEP

    1042:    Input Parameters:
    1043: +  pep    - the eigensolver context
    1044: .  scale  - scaling strategy
    1045: .  alpha  - the scaling factor used in the scalar strategy
    1046: .  Dl     - the left diagonal matrix of the diagonal scaling algorithm
    1047: .  Dr     - the right diagonal matrix of the diagonal scaling algorithm
    1048: .  its    - number of iterations of the diagonal scaling algorithm
    1049: -  lambda - approximation to wanted eigenvalues (modulus)

    1051:    Options Database Keys:
    1052: +  -pep_scale <type> - scaling type, one of <none,scalar,diagonal,both>
    1053: .  -pep_scale_factor <alpha> - the scaling factor
    1054: .  -pep_scale_its <its> - number of iterations
    1055: -  -pep_scale_lambda <lambda> - approximation to eigenvalues

    1057:    Notes:
    1058:    There are two non-exclusive scaling strategies: scalar and diagonal.

    1060:    In the scalar strategy, scaling is applied to the eigenvalue, that is,
    1061:    mu = lambda/alpha is the new eigenvalue and all matrices are scaled
    1062:    accordingly. After solving the scaled problem, the original lambda is
    1063:    recovered. Parameter 'alpha' must be positive. Use PETSC_DECIDE to let
    1064:    the solver compute a reasonable scaling factor.

    1066:    In the diagonal strategy, the solver works implicitly with matrix Dl*A*Dr,
    1067:    where Dl and Dr are appropriate diagonal matrices. This improves the accuracy
    1068:    of the computed results in some cases. The user may provide the Dr and Dl
    1069:    matrices represented as Vec objects storing diagonal elements. If not
    1070:    provided, these matrices are computed internally. This option requires
    1071:    that the polynomial coefficient matrices are of MATAIJ type.
    1072:    The parameter 'its' is the number of iterations performed by the method.
    1073:    Parameter 'lambda' must be positive. Use PETSC_DECIDE or set lambda = 1.0 if
    1074:    no information about eigenvalues is available.

    1076:    Level: intermediate

    1078: .seealso: PEPGetScale()
    1079: @*/
    1080: PetscErrorCode PEPSetScale(PEP pep,PEPScale scale,PetscReal alpha,Vec Dl,Vec Dr,PetscInt its,PetscReal lambda)
    1081: {

    1087:   pep->scale = scale;
    1088:   if (scale==PEP_SCALE_SCALAR || scale==PEP_SCALE_BOTH) {
    1090:     if (alpha == PETSC_DEFAULT || alpha == PETSC_DECIDE) {
    1091:       pep->sfactor = 0.0;
    1092:       pep->sfactor_set = PETSC_FALSE;
    1093:     } else {
    1094:       if (alpha<=0.0) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of alpha. Must be > 0");
    1095:       pep->sfactor = alpha;
    1096:       pep->sfactor_set = PETSC_TRUE;
    1097:     }
    1098:   }
    1099:   if (scale==PEP_SCALE_DIAGONAL || scale==PEP_SCALE_BOTH) {
    1100:     if (Dl) {
    1103:       PetscObjectReference((PetscObject)Dl);
    1104:       VecDestroy(&pep->Dl);
    1105:       pep->Dl = Dl;
    1106:     }
    1107:     if (Dr) {
    1110:       PetscObjectReference((PetscObject)Dr);
    1111:       VecDestroy(&pep->Dr);
    1112:       pep->Dr = Dr;
    1113:     }
    1116:     if (its==PETSC_DECIDE || its==PETSC_DEFAULT) pep->sits = 5;
    1117:     else pep->sits = its;
    1118:     if (lambda==PETSC_DECIDE || lambda==PETSC_DEFAULT) pep->slambda = 1.0;
    1119:     else if (lambda<=0.0) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of lambda. Must be > 0");
    1120:     else pep->slambda = lambda;
    1121:   }
    1122:   pep->state = PEP_STATE_INITIAL;
    1123:   return(0);
    1124: }

    1126: /*@C
    1127:    PEPGetScale - Gets the scaling strategy used by the PEP object, and the
    1128:    associated parameters.

    1130:    Not Collectiv, but vectors are shared by all processors that share the PEP

    1132:    Input Parameter:
    1133: .  pep - the eigensolver context

    1135:    Output Parameters:
    1136: +  scale  - scaling strategy
    1137: .  alpha  - the scaling factor used in the scalar strategy
    1138: .  Dl     - the left diagonal matrix of the diagonal scaling algorithm
    1139: .  Dr     - the right diagonal matrix of the diagonal scaling algorithm
    1140: .  its    - number of iterations of the diagonal scaling algorithm
    1141: -  lambda - approximation to wanted eigenvalues (modulus)

    1143:    Level: intermediate

    1145:    Note:
    1146:    The user can specify NULL for any parameter that is not needed.

    1148:    If Dl or Dr were not set by the user, then the ones computed internally are
    1149:    returned (or a null pointer if called before PEPSetUp).

    1151: .seealso: PEPSetScale(), PEPSetUp()
    1152: @*/
    1153: PetscErrorCode PEPGetScale(PEP pep,PEPScale *scale,PetscReal *alpha,Vec *Dl,Vec *Dr,PetscInt *its,PetscReal *lambda)
    1154: {
    1157:   if (scale)  *scale  = pep->scale;
    1158:   if (alpha)  *alpha  = pep->sfactor;
    1159:   if (Dl)     *Dl     = pep->Dl;
    1160:   if (Dr)     *Dr     = pep->Dr;
    1161:   if (its)    *its    = pep->sits;
    1162:   if (lambda) *lambda = pep->slambda;
    1163:   return(0);
    1164: }

    1166: /*@
    1167:    PEPSetExtract - Specifies the extraction strategy to be used.

    1169:    Logically Collective on PEP

    1171:    Input Parameters:
    1172: +  pep     - the eigensolver context
    1173: -  extract - extraction strategy

    1175:    Options Database Keys:
    1176: .  -pep_extract <type> - extraction type, one of <none,norm,residual,structured>

    1178:    Level: intermediate

    1180: .seealso: PEPGetExtract()
    1181: @*/
    1182: PetscErrorCode PEPSetExtract(PEP pep,PEPExtract extract)
    1183: {
    1187:   pep->extract = extract;
    1188:   return(0);
    1189: }

    1191: /*@
    1192:    PEPGetExtract - Gets the extraction strategy used by the PEP object.

    1194:    Not Collective

    1196:    Input Parameter:
    1197: .  pep - the eigensolver context

    1199:    Output Parameter:
    1200: .  extract - extraction strategy

    1202:    Level: intermediate

    1204: .seealso: PEPSetExtract()
    1205: @*/
    1206: PetscErrorCode PEPGetExtract(PEP pep,PEPExtract *extract)
    1207: {
    1210:   if (extract) *extract = pep->extract;
    1211:   return(0);
    1212: }

    1214: /*@
    1215:    PEPSetRefine - Specifies the refinement type (and options) to be used
    1216:    after the solve.

    1218:    Logically Collective on PEP

    1220:    Input Parameters:
    1221: +  pep    - the polynomial eigensolver context
    1222: .  refine - refinement type
    1223: .  npart  - number of partitions of the communicator
    1224: .  tol    - the convergence tolerance
    1225: .  its    - maximum number of refinement iterations
    1226: -  scheme - which scheme to be used for solving the involved linear systems

    1228:    Options Database Keys:
    1229: +  -pep_refine <type> - refinement type, one of <none,simple,multiple>
    1230: .  -pep_refine_partitions <n> - the number of partitions
    1231: .  -pep_refine_tol <tol> - the tolerance
    1232: .  -pep_refine_its <its> - number of iterations
    1233: -  -pep_refine_scheme - to set the scheme for the linear solves

    1235:    Notes:
    1236:    By default, iterative refinement is disabled, since it may be very
    1237:    costly. There are two possible refinement strategies: simple and multiple.
    1238:    The simple approach performs iterative refinement on each of the
    1239:    converged eigenpairs individually, whereas the multiple strategy works
    1240:    with the invariant pair as a whole, refining all eigenpairs simultaneously.
    1241:    The latter may be required for the case of multiple eigenvalues.

    1243:    In some cases, especially when using direct solvers within the
    1244:    iterative refinement method, it may be helpful for improved scalability
    1245:    to split the communicator in several partitions. The npart parameter
    1246:    indicates how many partitions to use (defaults to 1).

    1248:    The tol and its parameters specify the stopping criterion. In the simple
    1249:    method, refinement continues until the residual of each eigenpair is
    1250:    below the tolerance (tol defaults to the PEP tol, but may be set to a
    1251:    different value). In contrast, the multiple method simply performs its
    1252:    refinement iterations (just one by default).

    1254:    The scheme argument is used to change the way in which linear systems are
    1255:    solved. Possible choices are: explicit, mixed block elimination (MBE),
    1256:    and Schur complement.

    1258:    Level: intermediate

    1260: .seealso: PEPGetRefine()
    1261: @*/
    1262: PetscErrorCode PEPSetRefine(PEP pep,PEPRefine refine,PetscInt npart,PetscReal tol,PetscInt its,PEPRefineScheme scheme)
    1263: {
    1265:   PetscMPIInt    size;

    1274:   pep->refine = refine;
    1275:   if (refine) {  /* process parameters only if not REFINE_NONE */
    1276:     if (npart!=pep->npart) {
    1277:       PetscSubcommDestroy(&pep->refinesubc);
    1278:       KSPDestroy(&pep->refineksp);
    1279:     }
    1280:     if (npart == PETSC_DEFAULT || npart == PETSC_DECIDE) {
    1281:       pep->npart = 1;
    1282:     } else {
    1283:       MPI_Comm_size(PetscObjectComm((PetscObject)pep),&size);
    1284:       if (npart<1 || npart>size) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of npart");
    1285:       pep->npart = npart;
    1286:     }
    1287:     if (tol == PETSC_DEFAULT || tol == PETSC_DECIDE) {
    1288:       pep->rtol = PETSC_DEFAULT;
    1289:     } else {
    1290:       if (tol<=0.0) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of tol. Must be > 0");
    1291:       pep->rtol = tol;
    1292:     }
    1293:     if (its==PETSC_DECIDE || its==PETSC_DEFAULT) {
    1294:       pep->rits = PETSC_DEFAULT;
    1295:     } else {
    1296:       if (its<0) SETERRQ(PetscObjectComm((PetscObject)pep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of its. Must be >= 0");
    1297:       pep->rits = its;
    1298:     }
    1299:     pep->scheme = scheme;
    1300:   }
    1301:   pep->state = PEP_STATE_INITIAL;
    1302:   return(0);
    1303: }

    1305: /*@C
    1306:    PEPGetRefine - Gets the refinement strategy used by the PEP object, and the
    1307:    associated parameters.

    1309:    Not Collective

    1311:    Input Parameter:
    1312: .  pep - the polynomial eigensolver context

    1314:    Output Parameters:
    1315: +  refine - refinement type
    1316: .  npart  - number of partitions of the communicator
    1317: .  tol    - the convergence tolerance
    1318: .  its    - maximum number of refinement iterations
    1319: -  scheme - the scheme used for solving linear systems

    1321:    Level: intermediate

    1323:    Note:
    1324:    The user can specify NULL for any parameter that is not needed.

    1326: .seealso: PEPSetRefine()
    1327: @*/
    1328: PetscErrorCode PEPGetRefine(PEP pep,PEPRefine *refine,PetscInt *npart,PetscReal *tol,PetscInt *its,PEPRefineScheme *scheme)
    1329: {
    1332:   if (refine) *refine = pep->refine;
    1333:   if (npart)  *npart  = pep->npart;
    1334:   if (tol)    *tol    = pep->rtol;
    1335:   if (its)    *its    = pep->rits;
    1336:   if (scheme) *scheme = pep->scheme;
    1337:   return(0);
    1338: }

    1340: /*@C
    1341:    PEPSetOptionsPrefix - Sets the prefix used for searching for all
    1342:    PEP options in the database.

    1344:    Logically Collective on PEP

    1346:    Input Parameters:
    1347: +  pep - the polynomial eigensolver context
    1348: -  prefix - the prefix string to prepend to all PEP option requests

    1350:    Notes:
    1351:    A hyphen (-) must NOT be given at the beginning of the prefix name.
    1352:    The first character of all runtime options is AUTOMATICALLY the
    1353:    hyphen.

    1355:    For example, to distinguish between the runtime options for two
    1356:    different PEP contexts, one could call
    1357: .vb
    1358:       PEPSetOptionsPrefix(pep1,"qeig1_")
    1359:       PEPSetOptionsPrefix(pep2,"qeig2_")
    1360: .ve

    1362:    Level: advanced

    1364: .seealso: PEPAppendOptionsPrefix(), PEPGetOptionsPrefix()
    1365: @*/
    1366: PetscErrorCode PEPSetOptionsPrefix(PEP pep,const char *prefix)
    1367: {

    1372:   if (!pep->st) { PEPGetST(pep,&pep->st); }
    1373:   STSetOptionsPrefix(pep->st,prefix);
    1374:   if (!pep->V) { PEPGetBV(pep,&pep->V); }
    1375:   BVSetOptionsPrefix(pep->V,prefix);
    1376:   if (!pep->ds) { PEPGetDS(pep,&pep->ds); }
    1377:   DSSetOptionsPrefix(pep->ds,prefix);
    1378:   if (!pep->rg) { PEPGetRG(pep,&pep->rg); }
    1379:   RGSetOptionsPrefix(pep->rg,prefix);
    1380:   PetscObjectSetOptionsPrefix((PetscObject)pep,prefix);
    1381:   return(0);
    1382: }

    1384: /*@C
    1385:    PEPAppendOptionsPrefix - Appends to the prefix used for searching for all
    1386:    PEP options in the database.

    1388:    Logically Collective on PEP

    1390:    Input Parameters:
    1391: +  pep - the polynomial eigensolver context
    1392: -  prefix - the prefix string to prepend to all PEP option requests

    1394:    Notes:
    1395:    A hyphen (-) must NOT be given at the beginning of the prefix name.
    1396:    The first character of all runtime options is AUTOMATICALLY the hyphen.

    1398:    Level: advanced

    1400: .seealso: PEPSetOptionsPrefix(), PEPGetOptionsPrefix()
    1401: @*/
    1402: PetscErrorCode PEPAppendOptionsPrefix(PEP pep,const char *prefix)
    1403: {

    1408:   if (!pep->st) { PEPGetST(pep,&pep->st); }
    1409:   STAppendOptionsPrefix(pep->st,prefix);
    1410:   if (!pep->V) { PEPGetBV(pep,&pep->V); }
    1411:   BVAppendOptionsPrefix(pep->V,prefix);
    1412:   if (!pep->ds) { PEPGetDS(pep,&pep->ds); }
    1413:   DSAppendOptionsPrefix(pep->ds,prefix);
    1414:   if (!pep->rg) { PEPGetRG(pep,&pep->rg); }
    1415:   RGAppendOptionsPrefix(pep->rg,prefix);
    1416:   PetscObjectAppendOptionsPrefix((PetscObject)pep,prefix);
    1417:   return(0);
    1418: }

    1420: /*@C
    1421:    PEPGetOptionsPrefix - Gets the prefix used for searching for all
    1422:    PEP options in the database.

    1424:    Not Collective

    1426:    Input Parameters:
    1427: .  pep - the polynomial eigensolver context

    1429:    Output Parameters:
    1430: .  prefix - pointer to the prefix string used is returned

    1432:    Note:
    1433:    On the Fortran side, the user should pass in a string 'prefix' of
    1434:    sufficient length to hold the prefix.

    1436:    Level: advanced

    1438: .seealso: PEPSetOptionsPrefix(), PEPAppendOptionsPrefix()
    1439: @*/
    1440: PetscErrorCode PEPGetOptionsPrefix(PEP pep,const char *prefix[])
    1441: {

    1447:   PetscObjectGetOptionsPrefix((PetscObject)pep,prefix);
    1448:   return(0);
    1449: }