Date: 2024-10-28T09:13:18+00:00

Actual source code: krylovschur.c
slepc-3.22.1 2024-10-28
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

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

     13:    Method: Krylov-Schur

     15:    Algorithm:

     17:        Single-vector Krylov-Schur method for non-symmetric problems,
     18:        including harmonic extraction.

     20:    References:

     22:        [1] "Krylov-Schur Methods in SLEPc", SLEPc Technical Report STR-7,
     23:            available at https://slepc.upv.es.

     25:        [2] G.W. Stewart, "A Krylov-Schur Algorithm for Large Eigenproblems",
     26:            SIAM J. Matrix Anal. App. 23(3):601-614, 2001.

     28:        [3] "Practical Implementation of Harmonic Krylov-Schur", SLEPc Technical
     29:             Report STR-9, available at https://slepc.upv.es.
     30: */

     32: #include <slepc/private/epsimpl.h>
     33: #include "krylovschur.h"

     35: PetscErrorCode EPSGetArbitraryValues(EPS eps,PetscScalar *rr,PetscScalar *ri)
     36: {
     37:   PetscInt       i,newi,ld,n,l;
     38:   Vec            xr=eps->work[0],xi=eps->work[1];
     39:   PetscScalar    re,im,*Zr,*Zi,*X;

     41:   PetscFunctionBegin;
     42:   PetscCall(DSGetLeadingDimension(eps->ds,&ld));
     43:   PetscCall(DSGetDimensions(eps->ds,&n,&l,NULL,NULL));
     44:   for (i=l;i<n;i++) {
     45:     re = eps->eigr[i];
     46:     im = eps->eigi[i];
     47:     PetscCall(STBackTransform(eps->st,1,&re,&im));
     48:     newi = i;
     49:     PetscCall(DSVectors(eps->ds,DS_MAT_X,&newi,NULL));
     50:     PetscCall(DSGetArray(eps->ds,DS_MAT_X,&X));
     51:     Zr = X+i*ld;
     52:     if (newi==i+1) Zi = X+newi*ld;
     53:     else Zi = NULL;
     54:     PetscCall(EPSComputeRitzVector(eps,Zr,Zi,eps->V,xr,xi));
     55:     PetscCall(DSRestoreArray(eps->ds,DS_MAT_X,&X));
     56:     PetscCall((*eps->arbitrary)(re,im,xr,xi,rr+i,ri+i,eps->arbitraryctx));
     57:   }
     58:   PetscFunctionReturn(PETSC_SUCCESS);
     59: }

     61: static PetscErrorCode EPSSetUp_KrylovSchur_Filter(EPS eps)
     62: {
     63:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
     64:   PetscBool       estimaterange=PETSC_TRUE;
     65:   PetscReal       rleft,rright;
     66:   Mat             A;

     68:   PetscFunctionBegin;
     69:   EPSCheckHermitianCondition(eps,PETSC_TRUE," with polynomial filter");
     70:   EPSCheckStandardCondition(eps,PETSC_TRUE," with polynomial filter");
     71:   PetscCheck(eps->intb<PETSC_MAX_REAL || eps->inta>PETSC_MIN_REAL,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONG,"The defined computational interval should have at least one of their sides bounded");
     72:   EPSCheckUnsupportedCondition(eps,EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION | EPS_FEATURE_EXTRACTION,PETSC_TRUE," with polynomial filter");
     73:   if (eps->tol==(PetscReal)PETSC_DETERMINE) eps->tol = SLEPC_DEFAULT_TOL*1e-2;  /* use tighter tolerance */
     74:   PetscCall(STFilterSetInterval(eps->st,eps->inta,eps->intb));
     75:   if (!ctx->estimatedrange) {
     76:     PetscCall(STFilterGetRange(eps->st,&rleft,&rright));
     77:     estimaterange = (!rleft && !rright)? PETSC_TRUE: PETSC_FALSE;
     78:   }
     79:   if (estimaterange) { /* user did not set a range */
     80:     PetscCall(STGetMatrix(eps->st,0,&A));
     81:     PetscCall(MatEstimateSpectralRange_EPS(A,&rleft,&rright));
     82:     PetscCall(PetscInfo(eps,"Setting eigenvalue range to [%g,%g]\n",(double)rleft,(double)rright));
     83:     PetscCall(STFilterSetRange(eps->st,rleft,rright));
     84:     ctx->estimatedrange = PETSC_TRUE;
     85:   }
     86:   if (eps->ncv==PETSC_DETERMINE && eps->nev==1) eps->nev = 40;  /* user did not provide nev estimation */
     87:   PetscCall(EPSSetDimensions_Default(eps,eps->nev,&eps->ncv,&eps->mpd));
     88:   PetscCheck(eps->ncv<=eps->nev+eps->mpd,PetscObjectComm((PetscObject)eps),PETSC_ERR_USER_INPUT,"The value of ncv must not be larger than nev+mpd");
     89:   if (eps->max_it==PETSC_DETERMINE) eps->max_it = PetscMax(100,2*eps->n/eps->ncv);
     90:   PetscFunctionReturn(PETSC_SUCCESS);
     91: }

     93: static PetscErrorCode EPSSetUp_KrylovSchur(EPS eps)
     94: {
     95:   PetscReal         eta;
     96:   PetscBool         isfilt=PETSC_FALSE;
     97:   BVOrthogType      otype;
     98:   BVOrthogBlockType obtype;
     99:   EPS_KRYLOVSCHUR   *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    100:   enum { EPS_KS_DEFAULT,EPS_KS_SYMM,EPS_KS_SLICE,EPS_KS_FILTER,EPS_KS_INDEF,EPS_KS_TWOSIDED } variant;

    102:   PetscFunctionBegin;
    103:   if (eps->which==EPS_ALL) {  /* default values in case of spectrum slicing or polynomial filter  */
    104:     PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STFILTER,&isfilt));
    105:     if (isfilt) PetscCall(EPSSetUp_KrylovSchur_Filter(eps));
    106:     else PetscCall(EPSSetUp_KrylovSchur_Slice(eps));
    107:   } else if (eps->isstructured) {
    108:     PetscCall(EPSSetUp_KrylovSchur_BSE(eps));
    109:     PetscFunctionReturn(PETSC_SUCCESS);
    110:   } else {
    111:     PetscCall(EPSSetDimensions_Default(eps,eps->nev,&eps->ncv,&eps->mpd));
    112:     PetscCheck(eps->ncv<=eps->nev+eps->mpd,PetscObjectComm((PetscObject)eps),PETSC_ERR_USER_INPUT,"The value of ncv must not be larger than nev+mpd");
    113:     if (eps->max_it==PETSC_DETERMINE) eps->max_it = PetscMax(100,2*eps->n/eps->ncv);
    114:     if (!eps->which) PetscCall(EPSSetWhichEigenpairs_Default(eps));
    115:   }
    116:   PetscCheck(ctx->lock || eps->mpd>=eps->ncv,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"Should not use mpd parameter in non-locking variant");

    118:   EPSCheckDefiniteCondition(eps,eps->arbitrary," with arbitrary selection of eigenpairs");

    120:   PetscCheck(eps->extraction==EPS_RITZ || eps->extraction==EPS_HARMONIC,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"Unsupported extraction type");

    122:   if (!ctx->keep) ctx->keep = 0.5;

    124:   PetscCall(EPSAllocateSolution(eps,1));
    125:   PetscCall(EPS_SetInnerProduct(eps));
    126:   if (eps->arbitrary) PetscCall(EPSSetWorkVecs(eps,2));
    127:   else if (eps->ishermitian && !eps->ispositive) PetscCall(EPSSetWorkVecs(eps,1));

    129:   /* dispatch solve method */
    130:   if (eps->ishermitian) {
    131:     if (eps->which==EPS_ALL) {
    132:       EPSCheckDefiniteCondition(eps,eps->which==EPS_ALL," with spectrum slicing");
    133:       variant = isfilt? EPS_KS_FILTER: EPS_KS_SLICE;
    134:     } else if (eps->isgeneralized && !eps->ispositive) {
    135:       variant = EPS_KS_INDEF;
    136:     } else {
    137:       switch (eps->extraction) {
    138:         case EPS_RITZ:     variant = EPS_KS_SYMM; break;
    139:         case EPS_HARMONIC: variant = EPS_KS_DEFAULT; break;
    140:         default: SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"Unsupported extraction type");
    141:       }
    142:     }
    143:   } else if (eps->twosided) {
    144:     variant = EPS_KS_TWOSIDED;
    145:   } else {
    146:     switch (eps->extraction) {
    147:       case EPS_RITZ:     variant = EPS_KS_DEFAULT; break;
    148:       case EPS_HARMONIC: variant = EPS_KS_DEFAULT; break;
    149:       default: SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"Unsupported extraction type");
    150:     }
    151:   }
    152:   switch (variant) {
    153:     case EPS_KS_DEFAULT:
    154:       eps->ops->solve = EPSSolve_KrylovSchur_Default;
    155:       eps->ops->computevectors = EPSComputeVectors_Schur;
    156:       PetscCall(DSSetType(eps->ds,DSNHEP));
    157:       PetscCall(DSSetExtraRow(eps->ds,PETSC_TRUE));
    158:       PetscCall(DSAllocate(eps->ds,eps->ncv+1));
    159:       break;
    160:     case EPS_KS_SYMM:
    161:     case EPS_KS_FILTER:
    162:       eps->ops->solve = EPSSolve_KrylovSchur_Default;
    163:       eps->ops->computevectors = EPSComputeVectors_Hermitian;
    164:       PetscCall(DSSetType(eps->ds,DSHEP));
    165:       PetscCall(DSSetCompact(eps->ds,PETSC_TRUE));
    166:       PetscCall(DSSetExtraRow(eps->ds,PETSC_TRUE));
    167:       PetscCall(DSAllocate(eps->ds,eps->ncv+1));
    168:       break;
    169:     case EPS_KS_SLICE:
    170:       eps->ops->solve = EPSSolve_KrylovSchur_Slice;
    171:       eps->ops->computevectors = EPSComputeVectors_Slice;
    172:       break;
    173:     case EPS_KS_INDEF:
    174:       eps->ops->solve = EPSSolve_KrylovSchur_Indefinite;
    175:       eps->ops->computevectors = EPSComputeVectors_Indefinite;
    176:       PetscCall(DSSetType(eps->ds,DSGHIEP));
    177:       PetscCall(DSSetCompact(eps->ds,PETSC_TRUE));
    178:       PetscCall(DSSetExtraRow(eps->ds,PETSC_TRUE));
    179:       PetscCall(DSAllocate(eps->ds,eps->ncv+1));
    180:       /* force reorthogonalization for pseudo-Lanczos */
    181:       PetscCall(BVGetOrthogonalization(eps->V,&otype,NULL,&eta,&obtype));
    182:       PetscCall(BVSetOrthogonalization(eps->V,otype,BV_ORTHOG_REFINE_ALWAYS,eta,obtype));
    183:       break;
    184:     case EPS_KS_TWOSIDED:
    185:       eps->ops->solve = EPSSolve_KrylovSchur_TwoSided;
    186:       eps->ops->computevectors = EPSComputeVectors_Schur;
    187:       PetscCall(DSSetType(eps->ds,DSNHEPTS));
    188:       PetscCall(DSAllocate(eps->ds,eps->ncv+1));
    189:       PetscCall(DSSetExtraRow(eps->ds,PETSC_TRUE));
    190:       break;
    191:     default: SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_PLIB,"Unexpected error");
    192:   }
    193:   PetscFunctionReturn(PETSC_SUCCESS);
    194: }

    196: static PetscErrorCode EPSSetUpSort_KrylovSchur(EPS eps)
    197: {
    198:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    199:   SlepcSC         sc;
    200:   PetscBool       isfilt;

    202:   PetscFunctionBegin;
    203:   PetscCall(EPSSetUpSort_Default(eps));
    204:   if (eps->which==EPS_ALL) {
    205:     PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STFILTER,&isfilt));
    206:     if (isfilt) {
    207:       PetscCall(DSGetSlepcSC(eps->ds,&sc));
    208:       sc->rg            = NULL;
    209:       sc->comparison    = SlepcCompareLargestReal;
    210:       sc->comparisonctx = NULL;
    211:       sc->map           = NULL;
    212:       sc->mapobj        = NULL;
    213:     } else {
    214:       if (!ctx->global && ctx->sr->numEigs>0) {
    215:         PetscCall(DSGetSlepcSC(eps->ds,&sc));
    216:         sc->rg            = NULL;
    217:         sc->comparison    = SlepcCompareLargestMagnitude;
    218:         sc->comparisonctx = NULL;
    219:         sc->map           = NULL;
    220:         sc->mapobj        = NULL;
    221:       }
    222:     }
    223:   }
    224:   PetscFunctionReturn(PETSC_SUCCESS);
    225: }

    227: PetscErrorCode EPSSolve_KrylovSchur_Default(EPS eps)
    228: {
    229:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    230:   PetscInt        j,*pj,k,l,nv,ld,nconv;
    231:   Mat             U,Op,H,T;
    232:   PetscScalar     *g;
    233:   PetscReal       beta,gamma=1.0;
    234:   PetscBool       breakdown,harmonic,hermitian;

    236:   PetscFunctionBegin;
    237:   PetscCall(DSGetLeadingDimension(eps->ds,&ld));
    238:   harmonic = (eps->extraction==EPS_HARMONIC || eps->extraction==EPS_REFINED_HARMONIC)?PETSC_TRUE:PETSC_FALSE;
    239:   hermitian = (eps->ishermitian && !harmonic)?PETSC_TRUE:PETSC_FALSE;
    240:   if (harmonic) PetscCall(PetscMalloc1(ld,&g));
    241:   if (eps->arbitrary) pj = &j;
    242:   else pj = NULL;

    244:   /* Get the starting Arnoldi vector */
    245:   PetscCall(EPSGetStartVector(eps,0,NULL));
    246:   l = 0;

    248:   /* Restart loop */
    249:   while (eps->reason == EPS_CONVERGED_ITERATING) {
    250:     eps->its++;

    252:     /* Compute an nv-step Arnoldi factorization */
    253:     nv = PetscMin(eps->nconv+eps->mpd,eps->ncv);
    254:     PetscCall(DSSetDimensions(eps->ds,nv,eps->nconv,eps->nconv+l));
    255:     PetscCall(STGetOperator(eps->st,&Op));
    256:     if (hermitian) {
    257:       PetscCall(DSGetMat(eps->ds,DS_MAT_T,&T));
    258:       PetscCall(BVMatLanczos(eps->V,Op,T,eps->nconv+l,&nv,&beta,&breakdown));
    259:       PetscCall(DSRestoreMat(eps->ds,DS_MAT_T,&T));
    260:     } else {
    261:       PetscCall(DSGetMat(eps->ds,DS_MAT_A,&H));
    262:       PetscCall(BVMatArnoldi(eps->V,Op,H,eps->nconv+l,&nv,&beta,&breakdown));
    263:       PetscCall(DSRestoreMat(eps->ds,DS_MAT_A,&H));
    264:     }
    265:     PetscCall(STRestoreOperator(eps->st,&Op));
    266:     PetscCall(DSSetDimensions(eps->ds,nv,eps->nconv,eps->nconv+l));
    267:     PetscCall(DSSetState(eps->ds,l?DS_STATE_RAW:DS_STATE_INTERMEDIATE));
    268:     PetscCall(BVSetActiveColumns(eps->V,eps->nconv,nv));

    270:     /* Compute translation of Krylov decomposition if harmonic extraction used */
    271:     if (PetscUnlikely(harmonic)) PetscCall(DSTranslateHarmonic(eps->ds,eps->target,beta,PETSC_FALSE,g,&gamma));

    273:     /* Solve projected problem */
    274:     PetscCall(DSSolve(eps->ds,eps->eigr,eps->eigi));
    275:     if (PetscUnlikely(eps->arbitrary)) {
    276:       PetscCall(EPSGetArbitraryValues(eps,eps->rr,eps->ri));
    277:       j=1;
    278:     }
    279:     PetscCall(DSSort(eps->ds,eps->eigr,eps->eigi,eps->rr,eps->ri,pj));
    280:     PetscCall(DSUpdateExtraRow(eps->ds));
    281:     PetscCall(DSSynchronize(eps->ds,eps->eigr,eps->eigi));

    283:     /* Check convergence */
    284:     PetscCall(EPSKrylovConvergence(eps,PETSC_FALSE,eps->nconv,nv-eps->nconv,beta,0.0,gamma,&k));
    285:     PetscCall((*eps->stopping)(eps,eps->its,eps->max_it,k,eps->nev,&eps->reason,eps->stoppingctx));
    286:     nconv = k;

    288:     /* Update l */
    289:     if (eps->reason != EPS_CONVERGED_ITERATING || breakdown || k==nv) l = 0;
    290:     else {
    291:       l = PetscMax(1,(PetscInt)((nv-k)*ctx->keep));
    292:       if (!hermitian) PetscCall(DSGetTruncateSize(eps->ds,k,nv,&l));
    293:     }
    294:     if (!ctx->lock && l>0) { l += k; k = 0; } /* non-locking variant: reset no. of converged pairs */
    295:     if (l) PetscCall(PetscInfo(eps,"Preparing to restart keeping l=%" PetscInt_FMT " vectors\n",l));

    297:     if (eps->reason == EPS_CONVERGED_ITERATING) {
    298:       if (PetscUnlikely(breakdown || k==nv)) {
    299:         /* Start a new Arnoldi factorization */
    300:         PetscCall(PetscInfo(eps,"Breakdown in Krylov-Schur method (it=%" PetscInt_FMT " norm=%g)\n",eps->its,(double)beta));
    301:         if (k<eps->nev) {
    302:           PetscCall(EPSGetStartVector(eps,k,&breakdown));
    303:           if (breakdown) {
    304:             eps->reason = EPS_DIVERGED_BREAKDOWN;
    305:             PetscCall(PetscInfo(eps,"Unable to generate more start vectors\n"));
    306:           }
    307:         }
    308:       } else {
    309:         /* Undo translation of Krylov decomposition */
    310:         if (PetscUnlikely(harmonic)) {
    311:           PetscCall(DSSetDimensions(eps->ds,nv,k,l));
    312:           PetscCall(DSTranslateHarmonic(eps->ds,0.0,beta,PETSC_TRUE,g,&gamma));
    313:           /* gamma u^ = u - U*g~ */
    314:           PetscCall(BVSetActiveColumns(eps->V,0,nv));
    315:           PetscCall(BVMultColumn(eps->V,-1.0,1.0,nv,g));
    316:           PetscCall(BVScaleColumn(eps->V,nv,1.0/gamma));
    317:           PetscCall(BVSetActiveColumns(eps->V,eps->nconv,nv));
    318:           PetscCall(DSSetDimensions(eps->ds,nv,k,nv));
    319:         }
    320:         /* Prepare the Rayleigh quotient for restart */
    321:         PetscCall(DSTruncate(eps->ds,k+l,PETSC_FALSE));
    322:       }
    323:     }
    324:     /* Update the corresponding vectors V(:,idx) = V*Q(:,idx) */
    325:     PetscCall(DSGetMat(eps->ds,DS_MAT_Q,&U));
    326:     PetscCall(BVMultInPlace(eps->V,U,eps->nconv,k+l));
    327:     PetscCall(DSRestoreMat(eps->ds,DS_MAT_Q,&U));

    329:     if (eps->reason == EPS_CONVERGED_ITERATING && !breakdown) PetscCall(BVCopyColumn(eps->V,nv,k+l));
    330:     eps->nconv = k;
    331:     PetscCall(EPSMonitor(eps,eps->its,nconv,eps->eigr,eps->eigi,eps->errest,nv));
    332:   }

    334:   if (harmonic) PetscCall(PetscFree(g));
    335:   PetscCall(DSTruncate(eps->ds,eps->nconv,PETSC_TRUE));
    336:   PetscFunctionReturn(PETSC_SUCCESS);
    337: }

    339: static PetscErrorCode EPSKrylovSchurSetRestart_KrylovSchur(EPS eps,PetscReal keep)
    340: {
    341:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    343:   PetscFunctionBegin;
    344:   if (keep==(PetscReal)PETSC_DEFAULT || keep==(PetscReal)PETSC_DECIDE) ctx->keep = 0.5;
    345:   else {
    346:     PetscCheck(keep>=0.1 && keep<=0.9,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"The keep argument %g must be in the range [0.1,0.9]",(double)keep);
    347:     ctx->keep = keep;
    348:   }
    349:   PetscFunctionReturn(PETSC_SUCCESS);
    350: }

    352: /*@
    353:    EPSKrylovSchurSetRestart - Sets the restart parameter for the Krylov-Schur
    354:    method, in particular the proportion of basis vectors that must be kept
    355:    after restart.

    357:    Logically Collective

    359:    Input Parameters:
    360: +  eps - the eigenproblem solver context
    361: -  keep - the number of vectors to be kept at restart

    363:    Options Database Key:
    364: .  -eps_krylovschur_restart - Sets the restart parameter

    366:    Notes:
    367:    Allowed values are in the range [0.1,0.9]. The default is 0.5.

    369:    Level: advanced

    371: .seealso: EPSKrylovSchurGetRestart()
    372: @*/
    373: PetscErrorCode EPSKrylovSchurSetRestart(EPS eps,PetscReal keep)
    374: {
    375:   PetscFunctionBegin;
    378:   PetscTryMethod(eps,"EPSKrylovSchurSetRestart_C",(EPS,PetscReal),(eps,keep));
    379:   PetscFunctionReturn(PETSC_SUCCESS);
    380: }

    382: static PetscErrorCode EPSKrylovSchurGetRestart_KrylovSchur(EPS eps,PetscReal *keep)
    383: {
    384:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    386:   PetscFunctionBegin;
    387:   *keep = ctx->keep;
    388:   PetscFunctionReturn(PETSC_SUCCESS);
    389: }

    391: /*@
    392:    EPSKrylovSchurGetRestart - Gets the restart parameter used in the
    393:    Krylov-Schur method.

    395:    Not Collective

    397:    Input Parameter:
    398: .  eps - the eigenproblem solver context

    400:    Output Parameter:
    401: .  keep - the restart parameter

    403:    Level: advanced

    405: .seealso: EPSKrylovSchurSetRestart()
    406: @*/
    407: PetscErrorCode EPSKrylovSchurGetRestart(EPS eps,PetscReal *keep)
    408: {
    409:   PetscFunctionBegin;
    411:   PetscAssertPointer(keep,2);
    412:   PetscUseMethod(eps,"EPSKrylovSchurGetRestart_C",(EPS,PetscReal*),(eps,keep));
    413:   PetscFunctionReturn(PETSC_SUCCESS);
    414: }

    416: static PetscErrorCode EPSKrylovSchurSetLocking_KrylovSchur(EPS eps,PetscBool lock)
    417: {
    418:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    420:   PetscFunctionBegin;
    421:   ctx->lock = lock;
    422:   PetscFunctionReturn(PETSC_SUCCESS);
    423: }

    425: /*@
    426:    EPSKrylovSchurSetLocking - Choose between locking and non-locking variants of
    427:    the Krylov-Schur method.

    429:    Logically Collective

    431:    Input Parameters:
    432: +  eps  - the eigenproblem solver context
    433: -  lock - true if the locking variant must be selected

    435:    Options Database Key:
    436: .  -eps_krylovschur_locking - Sets the locking flag

    438:    Notes:
    439:    The default is to lock converged eigenpairs when the method restarts.
    440:    This behaviour can be changed so that all directions are kept in the
    441:    working subspace even if already converged to working accuracy (the
    442:    non-locking variant).

    444:    Level: advanced

    446: .seealso: EPSKrylovSchurGetLocking()
    447: @*/
    448: PetscErrorCode EPSKrylovSchurSetLocking(EPS eps,PetscBool lock)
    449: {
    450:   PetscFunctionBegin;
    453:   PetscTryMethod(eps,"EPSKrylovSchurSetLocking_C",(EPS,PetscBool),(eps,lock));
    454:   PetscFunctionReturn(PETSC_SUCCESS);
    455: }

    457: static PetscErrorCode EPSKrylovSchurGetLocking_KrylovSchur(EPS eps,PetscBool *lock)
    458: {
    459:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    461:   PetscFunctionBegin;
    462:   *lock = ctx->lock;
    463:   PetscFunctionReturn(PETSC_SUCCESS);
    464: }

    466: /*@
    467:    EPSKrylovSchurGetLocking - Gets the locking flag used in the Krylov-Schur
    468:    method.

    470:    Not Collective

    472:    Input Parameter:
    473: .  eps - the eigenproblem solver context

    475:    Output Parameter:
    476: .  lock - the locking flag

    478:    Level: advanced

    480: .seealso: EPSKrylovSchurSetLocking()
    481: @*/
    482: PetscErrorCode EPSKrylovSchurGetLocking(EPS eps,PetscBool *lock)
    483: {
    484:   PetscFunctionBegin;
    486:   PetscAssertPointer(lock,2);
    487:   PetscUseMethod(eps,"EPSKrylovSchurGetLocking_C",(EPS,PetscBool*),(eps,lock));
    488:   PetscFunctionReturn(PETSC_SUCCESS);
    489: }

    491: static PetscErrorCode EPSKrylovSchurSetPartitions_KrylovSchur(EPS eps,PetscInt npart)
    492: {
    493:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    494:   PetscMPIInt     size;
    495:   PetscInt        newnpart;

    497:   PetscFunctionBegin;
    498:   if (npart == PETSC_DEFAULT || npart == PETSC_DECIDE) {
    499:     newnpart = 1;
    500:   } else {
    501:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)eps),&size));
    502:     PetscCheck(npart>0 && npart<=size,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of npart");
    503:     newnpart = npart;
    504:   }
    505:   if (ctx->npart!=newnpart) {
    506:     if (ctx->npart>1) {
    507:       PetscCall(PetscSubcommDestroy(&ctx->subc));
    508:       if (ctx->commset) {
    509:         PetscCallMPI(MPI_Comm_free(&ctx->commrank));
    510:         ctx->commset = PETSC_FALSE;
    511:       }
    512:     }
    513:     PetscCall(EPSDestroy(&ctx->eps));
    514:     ctx->npart = newnpart;
    515:     eps->state = EPS_STATE_INITIAL;
    516:   }
    517:   PetscFunctionReturn(PETSC_SUCCESS);
    518: }

    520: /*@
    521:    EPSKrylovSchurSetPartitions - Sets the number of partitions for the
    522:    case of doing spectrum slicing for a computational interval with the
    523:    communicator split in several sub-communicators.

    525:    Logically Collective

    527:    Input Parameters:
    528: +  eps   - the eigenproblem solver context
    529: -  npart - number of partitions

    531:    Options Database Key:
    532: .  -eps_krylovschur_partitions <npart> - Sets the number of partitions

    534:    Notes:
    535:    By default, npart=1 so all processes in the communicator participate in
    536:    the processing of the whole interval. If npart>1 then the interval is
    537:    divided into npart subintervals, each of them being processed by a
    538:    subset of processes.

    540:    The interval is split proportionally unless the separation points are
    541:    specified with EPSKrylovSchurSetSubintervals().

    543:    Level: advanced

    545: .seealso: EPSKrylovSchurSetSubintervals(), EPSSetInterval()
    546: @*/
    547: PetscErrorCode EPSKrylovSchurSetPartitions(EPS eps,PetscInt npart)
    548: {
    549:   PetscFunctionBegin;
    552:   PetscTryMethod(eps,"EPSKrylovSchurSetPartitions_C",(EPS,PetscInt),(eps,npart));
    553:   PetscFunctionReturn(PETSC_SUCCESS);
    554: }

    556: static PetscErrorCode EPSKrylovSchurGetPartitions_KrylovSchur(EPS eps,PetscInt *npart)
    557: {
    558:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    560:   PetscFunctionBegin;
    561:   *npart  = ctx->npart;
    562:   PetscFunctionReturn(PETSC_SUCCESS);
    563: }

    565: /*@
    566:    EPSKrylovSchurGetPartitions - Gets the number of partitions of the
    567:    communicator in case of spectrum slicing.

    569:    Not Collective

    571:    Input Parameter:
    572: .  eps - the eigenproblem solver context

    574:    Output Parameter:
    575: .  npart - number of partitions

    577:    Level: advanced

    579: .seealso: EPSKrylovSchurSetPartitions()
    580: @*/
    581: PetscErrorCode EPSKrylovSchurGetPartitions(EPS eps,PetscInt *npart)
    582: {
    583:   PetscFunctionBegin;
    585:   PetscAssertPointer(npart,2);
    586:   PetscUseMethod(eps,"EPSKrylovSchurGetPartitions_C",(EPS,PetscInt*),(eps,npart));
    587:   PetscFunctionReturn(PETSC_SUCCESS);
    588: }

    590: static PetscErrorCode EPSKrylovSchurSetDetectZeros_KrylovSchur(EPS eps,PetscBool detect)
    591: {
    592:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    594:   PetscFunctionBegin;
    595:   ctx->detect = detect;
    596:   eps->state  = EPS_STATE_INITIAL;
    597:   PetscFunctionReturn(PETSC_SUCCESS);
    598: }

    600: /*@
    601:    EPSKrylovSchurSetDetectZeros - Sets a flag to enforce detection of
    602:    zeros during the factorizations throughout the spectrum slicing computation.

    604:    Logically Collective

    606:    Input Parameters:
    607: +  eps    - the eigenproblem solver context
    608: -  detect - check for zeros

    610:    Options Database Key:
    611: .  -eps_krylovschur_detect_zeros - Check for zeros; this takes an optional
    612:    bool value (0/1/no/yes/true/false)

    614:    Notes:
    615:    A zero in the factorization indicates that a shift coincides with an eigenvalue.

    617:    This flag is turned off by default, and may be necessary in some cases,
    618:    especially when several partitions are being used. This feature currently
    619:    requires an external package for factorizations with support for zero
    620:    detection, e.g. MUMPS.

    622:    Level: advanced

    624: .seealso: EPSKrylovSchurSetPartitions(), EPSSetInterval()
    625: @*/
    626: PetscErrorCode EPSKrylovSchurSetDetectZeros(EPS eps,PetscBool detect)
    627: {
    628:   PetscFunctionBegin;
    631:   PetscTryMethod(eps,"EPSKrylovSchurSetDetectZeros_C",(EPS,PetscBool),(eps,detect));
    632:   PetscFunctionReturn(PETSC_SUCCESS);
    633: }

    635: static PetscErrorCode EPSKrylovSchurGetDetectZeros_KrylovSchur(EPS eps,PetscBool *detect)
    636: {
    637:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    639:   PetscFunctionBegin;
    640:   *detect = ctx->detect;
    641:   PetscFunctionReturn(PETSC_SUCCESS);
    642: }

    644: /*@
    645:    EPSKrylovSchurGetDetectZeros - Gets the flag that enforces zero detection
    646:    in spectrum slicing.

    648:    Not Collective

    650:    Input Parameter:
    651: .  eps - the eigenproblem solver context

    653:    Output Parameter:
    654: .  detect - whether zeros detection is enforced during factorizations

    656:    Level: advanced

    658: .seealso: EPSKrylovSchurSetDetectZeros()
    659: @*/
    660: PetscErrorCode EPSKrylovSchurGetDetectZeros(EPS eps,PetscBool *detect)
    661: {
    662:   PetscFunctionBegin;
    664:   PetscAssertPointer(detect,2);
    665:   PetscUseMethod(eps,"EPSKrylovSchurGetDetectZeros_C",(EPS,PetscBool*),(eps,detect));
    666:   PetscFunctionReturn(PETSC_SUCCESS);
    667: }

    669: static PetscErrorCode EPSKrylovSchurSetDimensions_KrylovSchur(EPS eps,PetscInt nev,PetscInt ncv,PetscInt mpd)
    670: {
    671:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    673:   PetscFunctionBegin;
    674:   if (nev != PETSC_CURRENT) {
    675:     PetscCheck(nev>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of nev. Must be > 0");
    676:     ctx->nev = nev;
    677:   }
    678:   if (ncv == PETSC_DETERMINE) {
    679:     ctx->ncv = PETSC_DETERMINE;
    680:   } else if (ncv != PETSC_CURRENT) {
    681:     PetscCheck(ncv>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of ncv. Must be > 0");
    682:     ctx->ncv = ncv;
    683:   }
    684:   if (mpd == PETSC_DETERMINE) {
    685:     ctx->mpd = PETSC_DETERMINE;
    686:   } else if (mpd != PETSC_CURRENT) {
    687:     PetscCheck(mpd>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of mpd. Must be > 0");
    688:     ctx->mpd = mpd;
    689:   }
    690:   eps->state = EPS_STATE_INITIAL;
    691:   PetscFunctionReturn(PETSC_SUCCESS);
    692: }

    694: /*@
    695:    EPSKrylovSchurSetDimensions - Sets the dimensions used for each subsolve
    696:    step in case of doing spectrum slicing for a computational interval.
    697:    The meaning of the parameters is the same as in EPSSetDimensions().

    699:    Logically Collective

    701:    Input Parameters:
    702: +  eps - the eigenproblem solver context
    703: .  nev - number of eigenvalues to compute
    704: .  ncv - the maximum dimension of the subspace to be used by the subsolve
    705: -  mpd - the maximum dimension allowed for the projected problem

    707:    Options Database Key:
    708: +  -eps_krylovschur_nev <nev> - Sets the number of eigenvalues
    709: .  -eps_krylovschur_ncv <ncv> - Sets the dimension of the subspace
    710: -  -eps_krylovschur_mpd <mpd> - Sets the maximum projected dimension

    712:    Note:
    713:    Use PETSC_DETERMINE for ncv and mpd to assign a default value. For any
    714:    of the arguments, use PETSC_CURRENT to preserve the current value.

    716:    Level: advanced

    718: .seealso: EPSKrylovSchurGetDimensions(), EPSSetDimensions(), EPSSetInterval()
    719: @*/
    720: PetscErrorCode EPSKrylovSchurSetDimensions(EPS eps,PetscInt nev,PetscInt ncv,PetscInt mpd)
    721: {
    722:   PetscFunctionBegin;
    727:   PetscTryMethod(eps,"EPSKrylovSchurSetDimensions_C",(EPS,PetscInt,PetscInt,PetscInt),(eps,nev,ncv,mpd));
    728:   PetscFunctionReturn(PETSC_SUCCESS);
    729: }

    731: static PetscErrorCode EPSKrylovSchurGetDimensions_KrylovSchur(EPS eps,PetscInt *nev,PetscInt *ncv,PetscInt *mpd)
    732: {
    733:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    735:   PetscFunctionBegin;
    736:   if (nev) *nev = ctx->nev;
    737:   if (ncv) *ncv = ctx->ncv;
    738:   if (mpd) *mpd = ctx->mpd;
    739:   PetscFunctionReturn(PETSC_SUCCESS);
    740: }

    742: /*@
    743:    EPSKrylovSchurGetDimensions - Gets the dimensions used for each subsolve
    744:    step in case of doing spectrum slicing for a computational interval.

    746:    Not Collective

    748:    Input Parameter:
    749: .  eps - the eigenproblem solver context

    751:    Output Parameters:
    752: +  nev - number of eigenvalues to compute
    753: .  ncv - the maximum dimension of the subspace to be used by the subsolve
    754: -  mpd - the maximum dimension allowed for the projected problem

    756:    Level: advanced

    758: .seealso: EPSKrylovSchurSetDimensions()
    759: @*/
    760: PetscErrorCode EPSKrylovSchurGetDimensions(EPS eps,PetscInt *nev,PetscInt *ncv,PetscInt *mpd)
    761: {
    762:   PetscFunctionBegin;
    764:   PetscUseMethod(eps,"EPSKrylovSchurGetDimensions_C",(EPS,PetscInt*,PetscInt*,PetscInt*),(eps,nev,ncv,mpd));
    765:   PetscFunctionReturn(PETSC_SUCCESS);
    766: }

    768: static PetscErrorCode EPSKrylovSchurSetSubintervals_KrylovSchur(EPS eps,PetscReal* subint)
    769: {
    770:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    771:   PetscInt        i;

    773:   PetscFunctionBegin;
    774:   PetscCheck(subint[0]==eps->inta && subint[ctx->npart]==eps->intb,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONG,"First and last values must match the endpoints of EPSSetInterval()");
    775:   for (i=0;i<ctx->npart;i++) PetscCheck(subint[i]<=subint[i+1],PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONG,"Array must contain values in ascending order");
    776:   if (ctx->subintervals) PetscCall(PetscFree(ctx->subintervals));
    777:   PetscCall(PetscMalloc1(ctx->npart+1,&ctx->subintervals));
    778:   for (i=0;i<ctx->npart+1;i++) ctx->subintervals[i] = subint[i];
    779:   ctx->subintset = PETSC_TRUE;
    780:   eps->state = EPS_STATE_INITIAL;
    781:   PetscFunctionReturn(PETSC_SUCCESS);
    782: }

    784: /*@
    785:    EPSKrylovSchurSetSubintervals - Sets the points that delimit the
    786:    subintervals to be used in spectrum slicing with several partitions.

    788:    Logically Collective

    790:    Input Parameters:
    791: +  eps    - the eigenproblem solver context
    792: -  subint - array of real values specifying subintervals

    794:    Notes:
    795:    This function must be called after EPSKrylovSchurSetPartitions(). For npart
    796:    partitions, the argument subint must contain npart+1 real values sorted in
    797:    ascending order, subint_0, subint_1, ..., subint_npart, where the first
    798:    and last values must coincide with the interval endpoints set with
    799:    EPSSetInterval().

    801:    The subintervals are then defined by two consecutive points [subint_0,subint_1],
    802:    [subint_1,subint_2], and so on.

    804:    Level: advanced

    806: .seealso: EPSKrylovSchurSetPartitions(), EPSKrylovSchurGetSubintervals(), EPSSetInterval()
    807: @*/
    808: PetscErrorCode EPSKrylovSchurSetSubintervals(EPS eps,PetscReal subint[])
    809: {
    810:   PetscFunctionBegin;
    812:   PetscAssertPointer(subint,2);
    813:   PetscTryMethod(eps,"EPSKrylovSchurSetSubintervals_C",(EPS,PetscReal*),(eps,subint));
    814:   PetscFunctionReturn(PETSC_SUCCESS);
    815: }

    817: static PetscErrorCode EPSKrylovSchurGetSubintervals_KrylovSchur(EPS eps,PetscReal **subint)
    818: {
    819:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    820:   PetscInt        i;

    822:   PetscFunctionBegin;
    823:   if (!ctx->subintset) {
    824:     PetscCheck(eps->state,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Must call EPSSetUp() first");
    825:     PetscCheck(ctx->sr,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Only available in interval computations, see EPSSetInterval()");
    826:   }
    827:   PetscCall(PetscMalloc1(ctx->npart+1,subint));
    828:   for (i=0;i<=ctx->npart;i++) (*subint)[i] = ctx->subintervals[i];
    829:   PetscFunctionReturn(PETSC_SUCCESS);
    830: }

    832: /*@C
    833:    EPSKrylovSchurGetSubintervals - Returns the points that delimit the
    834:    subintervals used in spectrum slicing with several partitions.

    836:    Not Collective

    838:    Input Parameter:
    839: .  eps    - the eigenproblem solver context

    841:    Output Parameter:
    842: .  subint - array of real values specifying subintervals

    844:    Notes:
    845:    If the user passed values with EPSKrylovSchurSetSubintervals(), then the
    846:    same values are returned. Otherwise, the values computed internally are
    847:    obtained.

    849:    This function is only available for spectrum slicing runs.

    851:    The returned array has length npart+1 (see EPSKrylovSchurGetPartitions())
    852:    and should be freed by the user.

    854:    Fortran Notes:
    855:    The calling sequence from Fortran is
    856: .vb
    857:    EPSKrylovSchurGetSubintervals(eps,subint,ierr)
    858:    double precision subint(npart+1) output
    859: .ve

    861:    Level: advanced

    863: .seealso: EPSKrylovSchurSetSubintervals(), EPSKrylovSchurGetPartitions(), EPSSetInterval()
    864: @*/
    865: PetscErrorCode EPSKrylovSchurGetSubintervals(EPS eps,PetscReal **subint)
    866: {
    867:   PetscFunctionBegin;
    869:   PetscAssertPointer(subint,2);
    870:   PetscUseMethod(eps,"EPSKrylovSchurGetSubintervals_C",(EPS,PetscReal**),(eps,subint));
    871:   PetscFunctionReturn(PETSC_SUCCESS);
    872: }

    874: static PetscErrorCode EPSKrylovSchurGetInertias_KrylovSchur(EPS eps,PetscInt *n,PetscReal **shifts,PetscInt **inertias)
    875: {
    876:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    877:   PetscInt        i,numsh;
    878:   EPS_SR          sr = ctx->sr;

    880:   PetscFunctionBegin;
    881:   PetscCheck(eps->state,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Must call EPSSetUp() first");
    882:   PetscCheck(ctx->sr,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Only available in interval computations, see EPSSetInterval()");
    883:   switch (eps->state) {
    884:   case EPS_STATE_INITIAL:
    885:     break;
    886:   case EPS_STATE_SETUP:
    887:     numsh = ctx->npart+1;
    888:     if (n) *n = numsh;
    889:     if (shifts) {
    890:       PetscCall(PetscMalloc1(numsh,shifts));
    891:       (*shifts)[0] = eps->inta;
    892:       if (ctx->npart==1) (*shifts)[1] = eps->intb;
    893:       else for (i=1;i<numsh;i++) (*shifts)[i] = ctx->subintervals[i];
    894:     }
    895:     if (inertias) {
    896:       PetscCall(PetscMalloc1(numsh,inertias));
    897:       (*inertias)[0] = (sr->dir==1)?sr->inertia0:sr->inertia1;
    898:       if (ctx->npart==1) (*inertias)[1] = (sr->dir==1)?sr->inertia1:sr->inertia0;
    899:       else for (i=1;i<numsh;i++) (*inertias)[i] = (*inertias)[i-1]+ctx->nconv_loc[i-1];
    900:     }
    901:     break;
    902:   case EPS_STATE_SOLVED:
    903:   case EPS_STATE_EIGENVECTORS:
    904:     numsh = ctx->nshifts;
    905:     if (n) *n = numsh;
    906:     if (shifts) {
    907:       PetscCall(PetscMalloc1(numsh,shifts));
    908:       for (i=0;i<numsh;i++) (*shifts)[i] = ctx->shifts[i];
    909:     }
    910:     if (inertias) {
    911:       PetscCall(PetscMalloc1(numsh,inertias));
    912:       for (i=0;i<numsh;i++) (*inertias)[i] = ctx->inertias[i];
    913:     }
    914:     break;
    915:   }
    916:   PetscFunctionReturn(PETSC_SUCCESS);
    917: }

    919: /*@C
    920:    EPSKrylovSchurGetInertias - Gets the values of the shifts and their
    921:    corresponding inertias in case of doing spectrum slicing for a
    922:    computational interval.

    924:    Not Collective

    926:    Input Parameter:
    927: .  eps - the eigenproblem solver context

    929:    Output Parameters:
    930: +  n        - number of shifts, including the endpoints of the interval
    931: .  shifts   - the values of the shifts used internally in the solver
    932: -  inertias - the values of the inertia in each shift

    934:    Notes:
    935:    If called after EPSSolve(), all shifts used internally by the solver are
    936:    returned (including both endpoints and any intermediate ones). If called
    937:    before EPSSolve() and after EPSSetUp() then only the information of the
    938:    endpoints of subintervals is available.

    940:    This function is only available for spectrum slicing runs.

    942:    The returned arrays should be freed by the user. Can pass NULL in any of
    943:    the two arrays if not required.

    945:    Fortran Notes:
    946:    The calling sequence from Fortran is
    947: .vb
    948:    EPSKrylovSchurGetInertias(eps,n,shifts,inertias,ierr)
    949:    integer n
    950:    double precision shifts(*)
    951:    integer inertias(*)
    952: .ve
    953:    The arrays should be at least of length n. The value of n can be determined
    954:    by an initial call
    955: .vb
    956:    EPSKrylovSchurGetInertias(eps,n,PETSC_NULL_REAL_ARRAY,PETSC_NULL_INTEGER_ARRAY,ierr)
    957: .ve

    959:    Level: advanced

    961: .seealso: EPSSetInterval(), EPSKrylovSchurSetSubintervals()
    962: @*/
    963: PetscErrorCode EPSKrylovSchurGetInertias(EPS eps,PetscInt *n,PetscReal *shifts[],PetscInt *inertias[])
    964: {
    965:   PetscFunctionBegin;
    967:   PetscAssertPointer(n,2);
    968:   PetscUseMethod(eps,"EPSKrylovSchurGetInertias_C",(EPS,PetscInt*,PetscReal**,PetscInt**),(eps,n,shifts,inertias));
    969:   PetscFunctionReturn(PETSC_SUCCESS);
    970: }

    972: static PetscErrorCode EPSKrylovSchurGetSubcommInfo_KrylovSchur(EPS eps,PetscInt *k,PetscInt *n,Vec *v)
    973: {
    974:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    975:   EPS_SR          sr = ((EPS_KRYLOVSCHUR*)ctx->eps->data)->sr;

    977:   PetscFunctionBegin;
    978:   PetscCheck(eps->state,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Must call EPSSetUp() first");
    979:   PetscCheck(ctx->sr,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Only available in interval computations, see EPSSetInterval()");
    980:   if (k) *k = (ctx->npart==1)? 0: ctx->subc->color;
    981:   if (n) *n = sr->numEigs;
    982:   if (v) PetscCall(BVCreateVec(sr->V,v));
    983:   PetscFunctionReturn(PETSC_SUCCESS);
    984: }

    986: /*@
    987:    EPSKrylovSchurGetSubcommInfo - Gets information related to the case of
    988:    doing spectrum slicing for a computational interval with multiple
    989:    communicators.

    991:    Collective on the subcommunicator (if v is given)

    993:    Input Parameter:
    994: .  eps - the eigenproblem solver context

    996:    Output Parameters:
    997: +  k - index of the subinterval for the calling process
    998: .  n - number of eigenvalues found in the k-th subinterval
    999: -  v - a vector owned by processes in the subcommunicator with dimensions
    1000:        compatible for locally computed eigenvectors (or NULL)

    1002:    Notes:
    1003:    This function is only available for spectrum slicing runs.

    1005:    The returned Vec should be destroyed by the user.

    1007:    Level: advanced

    1009: .seealso: EPSSetInterval(), EPSKrylovSchurSetPartitions(), EPSKrylovSchurGetSubcommPairs()
    1010: @*/
    1011: PetscErrorCode EPSKrylovSchurGetSubcommInfo(EPS eps,PetscInt *k,PetscInt *n,Vec *v)
    1012: {
    1013:   PetscFunctionBegin;
    1015:   PetscUseMethod(eps,"EPSKrylovSchurGetSubcommInfo_C",(EPS,PetscInt*,PetscInt*,Vec*),(eps,k,n,v));
    1016:   PetscFunctionReturn(PETSC_SUCCESS);
    1017: }

    1019: static PetscErrorCode EPSKrylovSchurGetSubcommPairs_KrylovSchur(EPS eps,PetscInt i,PetscScalar *eig,Vec v)
    1020: {
    1021:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    1022:   EPS_SR          sr = ((EPS_KRYLOVSCHUR*)ctx->eps->data)->sr;

    1024:   PetscFunctionBegin;
    1025:   EPSCheckSolved(eps,1);
    1026:   PetscCheck(ctx->sr,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Only available in interval computations, see EPSSetInterval()");
    1027:   PetscCheck(i>=0 && i<sr->numEigs,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Argument 2 out of range");
    1028:   if (eig) *eig = sr->eigr[sr->perm[i]];
    1029:   if (v) PetscCall(BVCopyVec(sr->V,sr->perm[i],v));
    1030:   PetscFunctionReturn(PETSC_SUCCESS);
    1031: }

    1033: /*@
    1034:    EPSKrylovSchurGetSubcommPairs - Gets the i-th eigenpair stored
    1035:    internally in the subcommunicator to which the calling process belongs.

    1037:    Collective on the subcommunicator (if v is given)

    1039:    Input Parameters:
    1040: +  eps - the eigenproblem solver context
    1041: -  i   - index of the solution

    1043:    Output Parameters:
    1044: +  eig - the eigenvalue
    1045: -  v   - the eigenvector

    1047:    Notes:
    1048:    It is allowed to pass NULL for v if the eigenvector is not required.
    1049:    Otherwise, the caller must provide a valid Vec objects, i.e.,
    1050:    it must be created by the calling program with EPSKrylovSchurGetSubcommInfo().

    1052:    The index i should be a value between 0 and n-1, where n is the number of
    1053:    vectors in the local subinterval, see EPSKrylovSchurGetSubcommInfo().

    1055:    Level: advanced

    1057: .seealso: EPSSetInterval(), EPSKrylovSchurSetPartitions(), EPSKrylovSchurGetSubcommInfo(), EPSKrylovSchurGetSubcommMats()
    1058: @*/
    1059: PetscErrorCode EPSKrylovSchurGetSubcommPairs(EPS eps,PetscInt i,PetscScalar *eig,Vec v)
    1060: {
    1061:   PetscFunctionBegin;
    1064:   PetscUseMethod(eps,"EPSKrylovSchurGetSubcommPairs_C",(EPS,PetscInt,PetscScalar*,Vec),(eps,i,eig,v));
    1065:   PetscFunctionReturn(PETSC_SUCCESS);
    1066: }

    1068: static PetscErrorCode EPSKrylovSchurGetSubcommMats_KrylovSchur(EPS eps,Mat *A,Mat *B)
    1069: {
    1070:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    1072:   PetscFunctionBegin;
    1073:   PetscCheck(ctx->sr,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Only available in interval computations, see EPSSetInterval()");
    1074:   PetscCheck(eps->state,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Must call EPSSetUp() first");
    1075:   PetscCall(EPSGetOperators(ctx->eps,A,B));
    1076:   PetscFunctionReturn(PETSC_SUCCESS);
    1077: }

    1079: /*@
    1080:    EPSKrylovSchurGetSubcommMats - Gets the eigenproblem matrices stored
    1081:    internally in the subcommunicator to which the calling process belongs.

    1083:    Collective on the subcommunicator

    1085:    Input Parameter:
    1086: .  eps - the eigenproblem solver context

    1088:    Output Parameters:
    1089: +  A  - the matrix associated with the eigensystem
    1090: -  B  - the second matrix in the case of generalized eigenproblems

    1092:    Notes:
    1093:    This is the analog of EPSGetOperators(), but returns the matrices distributed
    1094:    differently (in the subcommunicator rather than in the parent communicator).

    1096:    These matrices should not be modified by the user.

    1098:    Level: advanced

    1100: .seealso: EPSSetInterval(), EPSKrylovSchurSetPartitions(), EPSKrylovSchurGetSubcommInfo()
    1101: @*/
    1102: PetscErrorCode EPSKrylovSchurGetSubcommMats(EPS eps,Mat *A,Mat *B)
    1103: {
    1104:   PetscFunctionBegin;
    1106:   PetscTryMethod(eps,"EPSKrylovSchurGetSubcommMats_C",(EPS,Mat*,Mat*),(eps,A,B));
    1107:   PetscFunctionReturn(PETSC_SUCCESS);
    1108: }

    1110: static PetscErrorCode EPSKrylovSchurUpdateSubcommMats_KrylovSchur(EPS eps,PetscScalar a,PetscScalar ap,Mat Au,PetscScalar b,PetscScalar bp, Mat Bu,MatStructure str,PetscBool globalup)
    1111: {
    1112:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data,*subctx;
    1113:   Mat             A,B=NULL,Ag,Bg=NULL;
    1114:   PetscBool       reuse=PETSC_TRUE;

    1116:   PetscFunctionBegin;
    1117:   PetscCheck(ctx->sr,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Only available in interval computations, see EPSSetInterval()");
    1118:   PetscCheck(eps->state,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Must call EPSSetUp() first");
    1119:   PetscCall(EPSGetOperators(eps,&Ag,&Bg));
    1120:   PetscCall(EPSGetOperators(ctx->eps,&A,&B));

    1122:   PetscCall(MatScale(A,a));
    1123:   if (Au) PetscCall(MatAXPY(A,ap,Au,str));
    1124:   if (B) PetscCall(MatScale(B,b));
    1125:   if (Bu) PetscCall(MatAXPY(B,bp,Bu,str));
    1126:   PetscCall(EPSSetOperators(ctx->eps,A,B));

    1128:   /* Update stored matrix state */
    1129:   subctx = (EPS_KRYLOVSCHUR*)ctx->eps->data;
    1130:   PetscCall(MatGetState(A,&subctx->Astate));
    1131:   if (B) PetscCall(MatGetState(B,&subctx->Bstate));

    1133:   /* Update matrices in the parent communicator if requested by user */
    1134:   if (globalup) {
    1135:     if (ctx->npart>1) {
    1136:       if (!ctx->isrow) {
    1137:         PetscCall(MatGetOwnershipIS(Ag,&ctx->isrow,&ctx->iscol));
    1138:         reuse = PETSC_FALSE;
    1139:       }
    1140:       if (str==DIFFERENT_NONZERO_PATTERN || str==UNKNOWN_NONZERO_PATTERN) reuse = PETSC_FALSE;
    1141:       if (ctx->submata && !reuse) PetscCall(MatDestroyMatrices(1,&ctx->submata));
    1142:       PetscCall(MatCreateSubMatrices(A,1,&ctx->isrow,&ctx->iscol,(reuse)?MAT_REUSE_MATRIX:MAT_INITIAL_MATRIX,&ctx->submata));
    1143:       PetscCall(MatCreateMPIMatConcatenateSeqMat(((PetscObject)Ag)->comm,ctx->submata[0],PETSC_DECIDE,MAT_REUSE_MATRIX,&Ag));
    1144:       if (B) {
    1145:         if (ctx->submatb && !reuse) PetscCall(MatDestroyMatrices(1,&ctx->submatb));
    1146:         PetscCall(MatCreateSubMatrices(B,1,&ctx->isrow,&ctx->iscol,(reuse)?MAT_REUSE_MATRIX:MAT_INITIAL_MATRIX,&ctx->submatb));
    1147:         PetscCall(MatCreateMPIMatConcatenateSeqMat(((PetscObject)Bg)->comm,ctx->submatb[0],PETSC_DECIDE,MAT_REUSE_MATRIX,&Bg));
    1148:       }
    1149:     }
    1150:     PetscCall(MatGetState(Ag,&ctx->Astate));
    1151:     if (Bg) PetscCall(MatGetState(Bg,&ctx->Bstate));
    1152:   }
    1153:   PetscCall(EPSSetOperators(eps,Ag,Bg));
    1154:   PetscFunctionReturn(PETSC_SUCCESS);
    1155: }

    1157: /*@
    1158:    EPSKrylovSchurUpdateSubcommMats - Update the eigenproblem matrices stored
    1159:    internally in the subcommunicator to which the calling process belongs.

    1161:    Collective

    1163:    Input Parameters:
    1164: +  eps - the eigenproblem solver context
    1165: .  s   - scalar that multiplies the existing A matrix
    1166: .  a   - scalar used in the axpy operation on A
    1167: .  Au  - matrix used in the axpy operation on A
    1168: .  t   - scalar that multiplies the existing B matrix
    1169: .  b   - scalar used in the axpy operation on B
    1170: .  Bu  - matrix used in the axpy operation on B
    1171: .  str - structure flag
    1172: -  globalup - flag indicating if global matrices must be updated

    1174:    Notes:
    1175:    This function modifies the eigenproblem matrices at the subcommunicator level,
    1176:    and optionally updates the global matrices in the parent communicator. The updates
    1177:    are expressed as A <-- s*A + a*Au,  B <-- t*B + b*Bu.

    1179:    It is possible to update one of the matrices, or both.

    1181:    The matrices Au and Bu must be equal in all subcommunicators.

    1183:    The str flag is passed to the MatAXPY() operations to perform the updates.

    1185:    If globalup is true, communication is carried out to reconstruct the updated
    1186:    matrices in the parent communicator. The user must be warned that if global
    1187:    matrices are not in sync with subcommunicator matrices, the errors computed
    1188:    by EPSComputeError() will be wrong even if the computed solution is correct
    1189:    (the synchronization may be done only once at the end).

    1191:    Level: advanced

    1193: .seealso: EPSSetInterval(), EPSKrylovSchurSetPartitions(), EPSKrylovSchurGetSubcommMats()
    1194: @*/
    1195: PetscErrorCode EPSKrylovSchurUpdateSubcommMats(EPS eps,PetscScalar s,PetscScalar a,Mat Au,PetscScalar t,PetscScalar b,Mat Bu,MatStructure str,PetscBool globalup)
    1196: {
    1197:   PetscFunctionBegin;
    1207:   PetscTryMethod(eps,"EPSKrylovSchurUpdateSubcommMats_C",(EPS,PetscScalar,PetscScalar,Mat,PetscScalar,PetscScalar,Mat,MatStructure,PetscBool),(eps,s,a,Au,t,b,Bu,str,globalup));
    1208:   PetscFunctionReturn(PETSC_SUCCESS);
    1209: }

    1211: PetscErrorCode EPSKrylovSchurGetChildEPS(EPS eps,EPS *childeps)
    1212: {
    1213:   EPS_KRYLOVSCHUR  *ctx=(EPS_KRYLOVSCHUR*)eps->data,*ctx_local;
    1214:   Mat              A,B=NULL,Ar=NULL,Br=NULL;
    1215:   PetscMPIInt      rank;
    1216:   PetscObjectState Astate,Bstate=0;
    1217:   PetscObjectId    Aid,Bid=0;
    1218:   STType           sttype;
    1219:   PetscInt         nmat;
    1220:   const char       *prefix;
    1221:   MPI_Comm         child;

    1223:   PetscFunctionBegin;
    1224:   PetscCall(EPSGetOperators(eps,&A,&B));
    1225:   if (ctx->npart==1) {
    1226:     if (!ctx->eps) PetscCall(EPSCreate(((PetscObject)eps)->comm,&ctx->eps));
    1227:     PetscCall(EPSGetOptionsPrefix(eps,&prefix));
    1228:     PetscCall(EPSSetOptionsPrefix(ctx->eps,prefix));
    1229:     PetscCall(EPSSetOperators(ctx->eps,A,B));
    1230:   } else {
    1231:     PetscCall(MatGetState(A,&Astate));
    1232:     PetscCall(PetscObjectGetId((PetscObject)A,&Aid));
    1233:     if (B) {
    1234:       PetscCall(MatGetState(B,&Bstate));
    1235:       PetscCall(PetscObjectGetId((PetscObject)B,&Bid));
    1236:     }
    1237:     if (!ctx->subc) {
    1238:       /* Create context for subcommunicators */
    1239:       PetscCall(PetscSubcommCreate(PetscObjectComm((PetscObject)eps),&ctx->subc));
    1240:       PetscCall(PetscSubcommSetNumber(ctx->subc,ctx->npart));
    1241:       PetscCall(PetscSubcommSetType(ctx->subc,PETSC_SUBCOMM_CONTIGUOUS));
    1242:       PetscCall(PetscSubcommGetChild(ctx->subc,&child));

    1244:       /* Duplicate matrices */
    1245:       PetscCall(MatCreateRedundantMatrix(A,0,child,MAT_INITIAL_MATRIX,&Ar));
    1246:       ctx->Astate = Astate;
    1247:       ctx->Aid = Aid;
    1248:       PetscCall(MatPropagateSymmetryOptions(A,Ar));
    1249:       if (B) {
    1250:         PetscCall(MatCreateRedundantMatrix(B,0,child,MAT_INITIAL_MATRIX,&Br));
    1251:         ctx->Bstate = Bstate;
    1252:         ctx->Bid = Bid;
    1253:         PetscCall(MatPropagateSymmetryOptions(B,Br));
    1254:       }
    1255:     } else {
    1256:       PetscCall(PetscSubcommGetChild(ctx->subc,&child));
    1257:       if (ctx->Astate != Astate || (B && ctx->Bstate != Bstate) || ctx->Aid != Aid || (B && ctx->Bid != Bid)) {
    1258:         PetscCall(STGetNumMatrices(ctx->eps->st,&nmat));
    1259:         if (nmat) PetscCall(EPSGetOperators(ctx->eps,&Ar,&Br));
    1260:         PetscCall(MatCreateRedundantMatrix(A,0,child,MAT_INITIAL_MATRIX,&Ar));
    1261:         ctx->Astate = Astate;
    1262:         ctx->Aid = Aid;
    1263:         PetscCall(MatPropagateSymmetryOptions(A,Ar));
    1264:         if (B) {
    1265:           PetscCall(MatCreateRedundantMatrix(B,0,child,MAT_INITIAL_MATRIX,&Br));
    1266:           ctx->Bstate = Bstate;
    1267:           ctx->Bid = Bid;
    1268:           PetscCall(MatPropagateSymmetryOptions(B,Br));
    1269:         }
    1270:         PetscCall(EPSSetOperators(ctx->eps,Ar,Br));
    1271:         PetscCall(MatDestroy(&Ar));
    1272:         PetscCall(MatDestroy(&Br));
    1273:       }
    1274:     }

    1276:     /* Create auxiliary EPS */
    1277:     if (!ctx->eps) {
    1278:       PetscCall(EPSCreate(child,&ctx->eps));
    1279:       PetscCall(EPSGetOptionsPrefix(eps,&prefix));
    1280:       PetscCall(EPSSetOptionsPrefix(ctx->eps,prefix));
    1281:       PetscCall(EPSSetOperators(ctx->eps,Ar,Br));
    1282:       PetscCall(MatDestroy(&Ar));
    1283:       PetscCall(MatDestroy(&Br));
    1284:     }
    1285:     /* Create subcommunicator grouping processes with same rank */
    1286:     if (!ctx->commset) {
    1287:       PetscCallMPI(MPI_Comm_rank(child,&rank));
    1288:       PetscCallMPI(MPI_Comm_split(((PetscObject)eps)->comm,rank,ctx->subc->color,&ctx->commrank));
    1289:       ctx->commset = PETSC_TRUE;
    1290:     }
    1291:   }
    1292:   PetscCall(EPSSetType(ctx->eps,((PetscObject)eps)->type_name));
    1293:   PetscCall(STGetType(eps->st,&sttype));
    1294:   PetscCall(STSetType(ctx->eps->st,sttype));

    1296:   ctx_local = (EPS_KRYLOVSCHUR*)ctx->eps->data;
    1297:   ctx_local->npart = ctx->npart;
    1298:   ctx_local->global = PETSC_FALSE;
    1299:   ctx_local->eps = eps;
    1300:   ctx_local->subc = ctx->subc;
    1301:   ctx_local->commrank = ctx->commrank;
    1302:   *childeps = ctx->eps;
    1303:   PetscFunctionReturn(PETSC_SUCCESS);
    1304: }

    1306: static PetscErrorCode EPSKrylovSchurGetKSP_KrylovSchur(EPS eps,KSP *ksp)
    1307: {
    1308:   EPS_KRYLOVSCHUR *ctx=(EPS_KRYLOVSCHUR*)eps->data;
    1309:   ST              st;
    1310:   PetscBool       isfilt;

    1312:   PetscFunctionBegin;
    1313:   PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STFILTER,&isfilt));
    1314:   PetscCheck(eps->which==EPS_ALL && !isfilt,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_WRONGSTATE,"Only available in interval computations with spectrum slicing");
    1315:   PetscCall(EPSKrylovSchurGetChildEPS(eps,&ctx->eps));
    1316:   PetscCall(EPSGetST(ctx->eps,&st));
    1317:   PetscCall(STGetOperator(st,NULL));
    1318:   PetscCall(STGetKSP(st,ksp));
    1319:   PetscFunctionReturn(PETSC_SUCCESS);
    1320: }

    1322: /*@
    1323:    EPSKrylovSchurGetKSP - Retrieve the linear solver object associated with the
    1324:    internal EPS object in case of doing spectrum slicing for a computational interval.

    1326:    Collective

    1328:    Input Parameter:
    1329: .  eps - the eigenproblem solver context

    1331:    Output Parameter:
    1332: .  ksp - the internal KSP object

    1334:    Notes:
    1335:    When invoked to compute all eigenvalues in an interval with spectrum
    1336:    slicing, EPSKRYLOVSCHUR creates another EPS object internally that is
    1337:    used to compute eigenvalues by chunks near selected shifts. This function
    1338:    allows access to the KSP object associated to this internal EPS object.

    1340:    This function is only available for spectrum slicing runs. In case of
    1341:    having more than one partition, the returned KSP will be different
    1342:    in MPI processes belonging to different partitions. Hence, if required,
    1343:    EPSKrylovSchurSetPartitions() must be called BEFORE this function.

    1345:    Level: advanced

    1347: .seealso: EPSSetInterval(), EPSKrylovSchurSetPartitions()
    1348: @*/
    1349: PetscErrorCode EPSKrylovSchurGetKSP(EPS eps,KSP *ksp)
    1350: {
    1351:   PetscFunctionBegin;
    1353:   PetscUseMethod(eps,"EPSKrylovSchurGetKSP_C",(EPS,KSP*),(eps,ksp));
    1354:   PetscFunctionReturn(PETSC_SUCCESS);
    1355: }

    1357: static PetscErrorCode EPSKrylovSchurSetBSEType_KrylovSchur(EPS eps,EPSKrylovSchurBSEType bse)
    1358: {
    1359:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    1361:   PetscFunctionBegin;
    1362:   switch (bse) {
    1363:     case EPS_KRYLOVSCHUR_BSE_SHAO:
    1364:     case EPS_KRYLOVSCHUR_BSE_GRUNING:
    1365:     case EPS_KRYLOVSCHUR_BSE_PROJECTEDBSE:
    1366:       if (ctx->bse != bse) {
    1367:         ctx->bse = bse;
    1368:         eps->state = EPS_STATE_INITIAL;
    1369:       }
    1370:       break;
    1371:     default:
    1372:       SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Invalid BSE type");
    1373:   }
    1374:   PetscFunctionReturn(PETSC_SUCCESS);
    1375: }

    1377: /*@
    1378:    EPSKrylovSchurSetBSEType - Sets the method to be used for BSE structured eigenproblems
    1379:    in the Krylov-Schur solver.

    1381:    Logically Collective

    1383:    Input Parameters:
    1384: +  eps - the eigenproblem solver context
    1385: -  bse - the BSE method

    1387:    Options Database Key:
    1388: .  -eps_krylovschur_bse_type - Sets the BSE type (either 'shao', 'gruning', or 'projectedbse')

    1390:    Level: advanced

    1392: .seealso: EPSKrylovSchurGetBSEType(), EPSKrylovSchurBSEType, MatCreateBSE()
    1393: @*/
    1394: PetscErrorCode EPSKrylovSchurSetBSEType(EPS eps,EPSKrylovSchurBSEType bse)
    1395: {
    1396:   PetscFunctionBegin;
    1399:   PetscTryMethod(eps,"EPSKrylovSchurSetBSEType_C",(EPS,EPSKrylovSchurBSEType),(eps,bse));
    1400:   PetscFunctionReturn(PETSC_SUCCESS);
    1401: }

    1403: static PetscErrorCode EPSKrylovSchurGetBSEType_KrylovSchur(EPS eps,EPSKrylovSchurBSEType *bse)
    1404: {
    1405:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;

    1407:   PetscFunctionBegin;
    1408:   *bse = ctx->bse;
    1409:   PetscFunctionReturn(PETSC_SUCCESS);
    1410: }

    1412: /*@
    1413:    EPSKrylovSchurGetBSEType - Gets the method used for BSE structured eigenproblems
    1414:    in the Krylov-Schur solver.

    1416:    Not Collective

    1418:    Input Parameter:
    1419: .  eps - the eigenproblem solver context

    1421:    Output Parameter:
    1422: .  bse - the BSE method

    1424:    Level: advanced

    1426: .seealso: EPSKrylovSchurSetBSEType(), EPSKrylovSchurBSEType, MatCreateBSE()
    1427: @*/
    1428: PetscErrorCode EPSKrylovSchurGetBSEType(EPS eps,EPSKrylovSchurBSEType *bse)
    1429: {
    1430:   PetscFunctionBegin;
    1432:   PetscAssertPointer(bse,2);
    1433:   PetscUseMethod(eps,"EPSKrylovSchurGetBSEType_C",(EPS,EPSKrylovSchurBSEType*),(eps,bse));
    1434:   PetscFunctionReturn(PETSC_SUCCESS);
    1435: }

    1437: static PetscErrorCode EPSSetFromOptions_KrylovSchur(EPS eps,PetscOptionItems *PetscOptionsObject)
    1438: {
    1439:   EPS_KRYLOVSCHUR       *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    1440:   PetscBool             flg,lock,b,f1,f2,f3,isfilt;
    1441:   PetscReal             keep;
    1442:   PetscInt              i,j,k;
    1443:   KSP                   ksp;
    1444:   EPSKrylovSchurBSEType bse;

    1446:   PetscFunctionBegin;
    1447:   PetscOptionsHeadBegin(PetscOptionsObject,"EPS Krylov-Schur Options");

    1449:     PetscCall(PetscOptionsReal("-eps_krylovschur_restart","Proportion of vectors kept after restart","EPSKrylovSchurSetRestart",0.5,&keep,&flg));
    1450:     if (flg) PetscCall(EPSKrylovSchurSetRestart(eps,keep));

    1452:     PetscCall(PetscOptionsBool("-eps_krylovschur_locking","Choose between locking and non-locking variants","EPSKrylovSchurSetLocking",PETSC_TRUE,&lock,&flg));
    1453:     if (flg) PetscCall(EPSKrylovSchurSetLocking(eps,lock));

    1455:     i = ctx->npart;
    1456:     PetscCall(PetscOptionsInt("-eps_krylovschur_partitions","Number of partitions of the communicator for spectrum slicing","EPSKrylovSchurSetPartitions",ctx->npart,&i,&flg));
    1457:     if (flg) PetscCall(EPSKrylovSchurSetPartitions(eps,i));

    1459:     b = ctx->detect;
    1460:     PetscCall(PetscOptionsBool("-eps_krylovschur_detect_zeros","Check zeros during factorizations at subinterval boundaries","EPSKrylovSchurSetDetectZeros",ctx->detect,&b,&flg));
    1461:     if (flg) PetscCall(EPSKrylovSchurSetDetectZeros(eps,b));

    1463:     i = 1;
    1464:     j = k = PETSC_DECIDE;
    1465:     PetscCall(PetscOptionsInt("-eps_krylovschur_nev","Number of eigenvalues to compute in each subsolve (only for spectrum slicing)","EPSKrylovSchurSetDimensions",40,&i,&f1));
    1466:     PetscCall(PetscOptionsInt("-eps_krylovschur_ncv","Number of basis vectors in each subsolve (only for spectrum slicing)","EPSKrylovSchurSetDimensions",80,&j,&f2));
    1467:     PetscCall(PetscOptionsInt("-eps_krylovschur_mpd","Maximum dimension of projected problem in each subsolve (only for spectrum slicing)","EPSKrylovSchurSetDimensions",80,&k,&f3));
    1468:     if (f1 || f2 || f3) PetscCall(EPSKrylovSchurSetDimensions(eps,i,j,k));

    1470:     PetscCall(PetscOptionsEnum("-eps_krylovschur_bse_type","Method for BSE structured eigenproblems","EPSKrylovSchurSetBSEType",EPSKrylovSchurBSETypes,(PetscEnum)ctx->bse,(PetscEnum*)&bse,&flg));
    1471:     if (flg) PetscCall(EPSKrylovSchurSetBSEType(eps,bse));

    1473:   PetscOptionsHeadEnd();

    1475:   /* set options of child KSP in spectrum slicing */
    1476:   if (eps->which==EPS_ALL) {
    1477:     if (!eps->st) PetscCall(EPSGetST(eps,&eps->st));
    1478:     PetscCall(EPSSetDefaultST(eps));
    1479:     PetscCall(STSetFromOptions(eps->st));  /* need to advance this to check ST type */
    1480:     PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STFILTER,&isfilt));
    1481:     if (!isfilt) {
    1482:       PetscCall(EPSKrylovSchurGetKSP_KrylovSchur(eps,&ksp));
    1483:       PetscCall(KSPSetFromOptions(ksp));
    1484:     }
    1485:   }
    1486:   PetscFunctionReturn(PETSC_SUCCESS);
    1487: }

    1489: static PetscErrorCode EPSView_KrylovSchur(EPS eps,PetscViewer viewer)
    1490: {
    1491:   EPS_KRYLOVSCHUR *ctx = (EPS_KRYLOVSCHUR*)eps->data;
    1492:   PetscBool       isascii,isfilt;
    1493:   KSP             ksp;
    1494:   PetscViewer     sviewer;

    1496:   PetscFunctionBegin;
    1497:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii));
    1498:   if (isascii) {
    1499:     PetscCall(PetscViewerASCIIPrintf(viewer,"  %d%% of basis vectors kept after restart\n",(int)(100*ctx->keep)));
    1500:     PetscCall(PetscViewerASCIIPrintf(viewer,"  using the %slocking variant\n",ctx->lock?"":"non-"));
    1501:     if (eps->problem_type==EPS_BSE) PetscCall(PetscViewerASCIIPrintf(viewer,"  BSE method: %s\n",EPSKrylovSchurBSETypes[ctx->bse]));
    1502:     if (eps->which==EPS_ALL) {
    1503:       PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STFILTER,&isfilt));
    1504:       if (isfilt) PetscCall(PetscViewerASCIIPrintf(viewer,"  using filtering to extract all eigenvalues in an interval\n"));
    1505:       else {
    1506:         PetscCall(PetscViewerASCIIPrintf(viewer,"  doing spectrum slicing with nev=%" PetscInt_FMT ", ncv=%" PetscInt_FMT ", mpd=%" PetscInt_FMT "\n",ctx->nev,ctx->ncv,ctx->mpd));
    1507:         if (ctx->npart>1) {
    1508:           PetscCall(PetscViewerASCIIPrintf(viewer,"  multi-communicator spectrum slicing with %" PetscInt_FMT " partitions\n",ctx->npart));
    1509:           if (ctx->detect) PetscCall(PetscViewerASCIIPrintf(viewer,"  detecting zeros when factorizing at subinterval boundaries\n"));
    1510:         }
    1511:         /* view child KSP */
    1512:         PetscCall(EPSKrylovSchurGetKSP_KrylovSchur(eps,&ksp));
    1513:         PetscCall(PetscViewerASCIIPushTab(viewer));
    1514:         if (ctx->npart>1 && ctx->subc) {
    1515:           PetscCall(PetscViewerGetSubViewer(viewer,ctx->subc->child,&sviewer));
    1516:           if (!ctx->subc->color) PetscCall(KSPView(ksp,sviewer));
    1517:           PetscCall(PetscViewerFlush(sviewer));
    1518:           PetscCall(PetscViewerRestoreSubViewer(viewer,ctx->subc->child,&sviewer));
    1519:           /* extra call needed because of the two calls to PetscViewerASCIIPushSynchronized() in PetscViewerGetSubViewer() */
    1520:           PetscCall(PetscViewerASCIIPopSynchronized(viewer));
    1521:         } else PetscCall(KSPView(ksp,viewer));
    1522:         PetscCall(PetscViewerASCIIPopTab(viewer));
    1523:       }
    1524:     }
    1525:   }
    1526:   PetscFunctionReturn(PETSC_SUCCESS);
    1527: }

    1529: static PetscErrorCode EPSDestroy_KrylovSchur(EPS eps)
    1530: {
    1531:   PetscBool      isfilt;

    1533:   PetscFunctionBegin;
    1534:   PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STFILTER,&isfilt));
    1535:   if (eps->which==EPS_ALL && !isfilt) PetscCall(EPSDestroy_KrylovSchur_Slice(eps));
    1536:   PetscCall(PetscFree(eps->data));
    1537:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetRestart_C",NULL));
    1538:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetRestart_C",NULL));
    1539:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetLocking_C",NULL));
    1540:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetLocking_C",NULL));
    1541:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetPartitions_C",NULL));
    1542:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetPartitions_C",NULL));
    1543:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetDetectZeros_C",NULL));
    1544:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetDetectZeros_C",NULL));
    1545:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetDimensions_C",NULL));
    1546:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetDimensions_C",NULL));
    1547:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetSubintervals_C",NULL));
    1548:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubintervals_C",NULL));
    1549:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetInertias_C",NULL));
    1550:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubcommInfo_C",NULL));
    1551:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubcommPairs_C",NULL));
    1552:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubcommMats_C",NULL));
    1553:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurUpdateSubcommMats_C",NULL));
    1554:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetKSP_C",NULL));
    1555:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetBSEType_C",NULL));
    1556:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetBSEType_C",NULL));
    1557:   PetscFunctionReturn(PETSC_SUCCESS);
    1558: }

    1560: static PetscErrorCode EPSReset_KrylovSchur(EPS eps)
    1561: {
    1562:   PetscBool      isfilt;

    1564:   PetscFunctionBegin;
    1565:   PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STFILTER,&isfilt));
    1566:   if (eps->which==EPS_ALL && !isfilt) PetscCall(EPSReset_KrylovSchur_Slice(eps));
    1567:   PetscFunctionReturn(PETSC_SUCCESS);
    1568: }

    1570: static PetscErrorCode EPSSetDefaultST_KrylovSchur(EPS eps)
    1571: {
    1572:   PetscFunctionBegin;
    1573:   if (eps->which==EPS_ALL) {
    1574:     if (!((PetscObject)eps->st)->type_name) PetscCall(STSetType(eps->st,STSINVERT));
    1575:   }
    1576:   PetscFunctionReturn(PETSC_SUCCESS);
    1577: }

    1579: SLEPC_EXTERN PetscErrorCode EPSCreate_KrylovSchur(EPS eps)
    1580: {
    1581:   EPS_KRYLOVSCHUR *ctx;

    1583:   PetscFunctionBegin;
    1584:   PetscCall(PetscNew(&ctx));
    1585:   eps->data   = (void*)ctx;
    1586:   ctx->lock   = PETSC_TRUE;
    1587:   ctx->nev    = 1;
    1588:   ctx->ncv    = PETSC_DETERMINE;
    1589:   ctx->mpd    = PETSC_DETERMINE;
    1590:   ctx->npart  = 1;
    1591:   ctx->detect = PETSC_FALSE;
    1592:   ctx->global = PETSC_TRUE;

    1594:   eps->useds = PETSC_TRUE;

    1596:   /* solve and computevectors determined at setup */
    1597:   eps->ops->setup          = EPSSetUp_KrylovSchur;
    1598:   eps->ops->setupsort      = EPSSetUpSort_KrylovSchur;
    1599:   eps->ops->setfromoptions = EPSSetFromOptions_KrylovSchur;
    1600:   eps->ops->destroy        = EPSDestroy_KrylovSchur;
    1601:   eps->ops->reset          = EPSReset_KrylovSchur;
    1602:   eps->ops->view           = EPSView_KrylovSchur;
    1603:   eps->ops->backtransform  = EPSBackTransform_Default;
    1604:   eps->ops->setdefaultst   = EPSSetDefaultST_KrylovSchur;

    1606:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetRestart_C",EPSKrylovSchurSetRestart_KrylovSchur));
    1607:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetRestart_C",EPSKrylovSchurGetRestart_KrylovSchur));
    1608:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetLocking_C",EPSKrylovSchurSetLocking_KrylovSchur));
    1609:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetLocking_C",EPSKrylovSchurGetLocking_KrylovSchur));
    1610:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetPartitions_C",EPSKrylovSchurSetPartitions_KrylovSchur));
    1611:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetPartitions_C",EPSKrylovSchurGetPartitions_KrylovSchur));
    1612:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetDetectZeros_C",EPSKrylovSchurSetDetectZeros_KrylovSchur));
    1613:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetDetectZeros_C",EPSKrylovSchurGetDetectZeros_KrylovSchur));
    1614:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetDimensions_C",EPSKrylovSchurSetDimensions_KrylovSchur));
    1615:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetDimensions_C",EPSKrylovSchurGetDimensions_KrylovSchur));
    1616:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetSubintervals_C",EPSKrylovSchurSetSubintervals_KrylovSchur));
    1617:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubintervals_C",EPSKrylovSchurGetSubintervals_KrylovSchur));
    1618:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetInertias_C",EPSKrylovSchurGetInertias_KrylovSchur));
    1619:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubcommInfo_C",EPSKrylovSchurGetSubcommInfo_KrylovSchur));
    1620:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubcommPairs_C",EPSKrylovSchurGetSubcommPairs_KrylovSchur));
    1621:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetSubcommMats_C",EPSKrylovSchurGetSubcommMats_KrylovSchur));
    1622:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurUpdateSubcommMats_C",EPSKrylovSchurUpdateSubcommMats_KrylovSchur));
    1623:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetKSP_C",EPSKrylovSchurGetKSP_KrylovSchur));
    1624:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurSetBSEType_C",EPSKrylovSchurSetBSEType_KrylovSchur));
    1625:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSKrylovSchurGetBSEType_C",EPSKrylovSchurGetBSEType_KrylovSchur));
    1626:   PetscFunctionReturn(PETSC_SUCCESS);
    1627: }