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

Actual source code: nepsetup.c
slepc-3.14.2 2021-02-01
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2020, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */
     10: /*
     11:    NEP routines related to problem setup
     12: */

     14: #include <slepc/private/nepimpl.h>

     16: /*@
     17:    NEPSetUp - Sets up all the internal data structures necessary for the
     18:    execution of the NEP solver.

     20:    Collective on nep

     22:    Input Parameter:
     23: .  nep   - solver context

     25:    Notes:
     26:    This function need not be called explicitly in most cases, since NEPSolve()
     27:    calls it. It can be useful when one wants to measure the set-up time
     28:    separately from the solve time.

     30:    Level: developer

     32: .seealso: NEPCreate(), NEPSolve(), NEPDestroy()
     33: @*/
     34: PetscErrorCode NEPSetUp(NEP nep)
     35: {
     37:   PetscInt       k;
     38:   SlepcSC        sc;
     39:   Mat            T;
     40:   PetscBool      flg;
     41:   KSP            ksp;
     42:   PC             pc;
     43:   PetscMPIInt    size;
     44:   MatSolverType  stype;

     48:   NEPCheckProblem(nep,1);
     49:   if (nep->state) return(0);
     50:   PetscLogEventBegin(NEP_SetUp,nep,0,0,0);

     52:   /* reset the convergence flag from the previous solves */
     53:   nep->reason = NEP_CONVERGED_ITERATING;

     55:   /* set default solver type (NEPSetFromOptions was not called) */
     56:   if (!((PetscObject)nep)->type_name) {
     57:     NEPSetType(nep,NEPRII);
     58:   }
     59:   if (nep->useds && !nep->ds) { NEPGetDS(nep,&nep->ds); }
     60:   if (!nep->rg) { NEPGetRG(nep,&nep->rg); }
     61:   if (!((PetscObject)nep->rg)->type_name) {
     62:     RGSetType(nep->rg,RGINTERVAL);
     63:   }

     65:   /* set problem dimensions */
     66:   switch (nep->fui) {
     67:   case NEP_USER_INTERFACE_CALLBACK:
     68:     NEPGetFunction(nep,&T,NULL,NULL,NULL);
     69:     MatGetSize(T,&nep->n,NULL);
     70:     MatGetLocalSize(T,&nep->nloc,NULL);
     71:     break;
     72:   case NEP_USER_INTERFACE_SPLIT:
     73:     MatDuplicate(nep->A[0],MAT_DO_NOT_COPY_VALUES,&nep->function);
     74:     MatDuplicate(nep->A[0],MAT_DO_NOT_COPY_VALUES,&nep->jacobian);
     75:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->function);
     76:     PetscLogObjectParent((PetscObject)nep,(PetscObject)nep->jacobian);
     77:     MatGetSize(nep->A[0],&nep->n,NULL);
     78:     MatGetLocalSize(nep->A[0],&nep->nloc,NULL);
     79:     break;
     80:   }

     82:   /* set default problem type */
     83:   if (!nep->problem_type) {
     84:     NEPSetProblemType(nep,NEP_GENERAL);
     85:   }

     87:   /* check consistency of refinement options */
     88:   if (nep->refine) {
     89:     if (nep->fui!=NEP_USER_INTERFACE_SPLIT) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"Iterative refinement only implemented in split form");
     90:     if (!nep->scheme) {  /* set default scheme */
     91:       NEPRefineGetKSP(nep,&ksp);
     92:       KSPGetPC(ksp,&pc);
     93:       PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
     94:       if (flg) {
     95:         PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
     96:       }
     97:       nep->scheme = flg? NEP_REFINE_SCHEME_MBE: NEP_REFINE_SCHEME_SCHUR;
     98:     }
     99:     if (nep->scheme==NEP_REFINE_SCHEME_MBE) {
    100:       NEPRefineGetKSP(nep,&ksp);
    101:       KSPGetPC(ksp,&pc);
    102:       PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
    103:       if (flg) {
    104:         PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
    105:       }
    106:       if (!flg) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"The MBE scheme for refinement requires a direct solver in KSP");
    107:       MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
    108:       if (size>1) {   /* currently selected PC is a factorization */
    109:         PCFactorGetMatSolverType(pc,&stype);
    110:         PetscStrcmp(stype,MATSOLVERPETSC,&flg);
    111:         if (flg) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"For Newton refinement, you chose to solve linear systems with a factorization, but in parallel runs you need to select an external package");
    112:       }
    113:     }
    114:     if (nep->scheme==NEP_REFINE_SCHEME_SCHUR) {
    115:       if (nep->npart>1) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"The Schur scheme for refinement does not support subcommunicators");
    116:     }
    117:   }
    118:   /* call specific solver setup */
    119:   (*nep->ops->setup)(nep);

    121:   /* set tolerance if not yet set */
    122:   if (nep->tol==PETSC_DEFAULT) nep->tol = SLEPC_DEFAULT_TOL;
    123:   if (nep->refine) {
    124:     if (nep->rtol==PETSC_DEFAULT) nep->rtol = PetscMax(nep->tol/1000,PETSC_MACHINE_EPSILON);
    125:     if (nep->rits==PETSC_DEFAULT) nep->rits = (nep->refine==NEP_REFINE_SIMPLE)? 10: 1;
    126:   }

    128:   /* fill sorting criterion context */
    129:   switch (nep->which) {
    130:     case NEP_LARGEST_MAGNITUDE:
    131:       nep->sc->comparison    = SlepcCompareLargestMagnitude;
    132:       nep->sc->comparisonctx = NULL;
    133:       break;
    134:     case NEP_SMALLEST_MAGNITUDE:
    135:       nep->sc->comparison    = SlepcCompareSmallestMagnitude;
    136:       nep->sc->comparisonctx = NULL;
    137:       break;
    138:     case NEP_LARGEST_REAL:
    139:       nep->sc->comparison    = SlepcCompareLargestReal;
    140:       nep->sc->comparisonctx = NULL;
    141:       break;
    142:     case NEP_SMALLEST_REAL:
    143:       nep->sc->comparison    = SlepcCompareSmallestReal;
    144:       nep->sc->comparisonctx = NULL;
    145:       break;
    146:     case NEP_LARGEST_IMAGINARY:
    147:       nep->sc->comparison    = SlepcCompareLargestImaginary;
    148:       nep->sc->comparisonctx = NULL;
    149:       break;
    150:     case NEP_SMALLEST_IMAGINARY:
    151:       nep->sc->comparison    = SlepcCompareSmallestImaginary;
    152:       nep->sc->comparisonctx = NULL;
    153:       break;
    154:     case NEP_TARGET_MAGNITUDE:
    155:       nep->sc->comparison    = SlepcCompareTargetMagnitude;
    156:       nep->sc->comparisonctx = &nep->target;
    157:       break;
    158:     case NEP_TARGET_REAL:
    159:       nep->sc->comparison    = SlepcCompareTargetReal;
    160:       nep->sc->comparisonctx = &nep->target;
    161:       break;
    162:     case NEP_TARGET_IMAGINARY:
    163: #if defined(PETSC_USE_COMPLEX)
    164:       nep->sc->comparison    = SlepcCompareTargetImaginary;
    165:       nep->sc->comparisonctx = &nep->target;
    166: #endif
    167:       break;
    168:     case NEP_ALL:
    169:       nep->sc->comparison    = SlepcCompareSmallestReal;
    170:       nep->sc->comparisonctx = NULL;
    171:       break;
    172:     case NEP_WHICH_USER:
    173:       break;
    174:   }

    176:   nep->sc->map    = NULL;
    177:   nep->sc->mapobj = NULL;

    179:   /* fill sorting criterion for DS */
    180:   if (nep->useds) {
    181:     DSGetSlepcSC(nep->ds,&sc);
    182:     sc->comparison    = nep->sc->comparison;
    183:     sc->comparisonctx = nep->sc->comparisonctx;
    184:     PetscObjectTypeCompare((PetscObject)nep,NEPNLEIGS,&flg);
    185:     if (!flg) {
    186:       sc->map    = NULL;
    187:       sc->mapobj = NULL;
    188:     }
    189:   }
    190:   if (nep->nev > nep->ncv) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"nev bigger than ncv");

    192:   /* process initial vectors */
    193:   if (nep->nini<0) {
    194:     k = -nep->nini;
    195:     if (k>nep->ncv) SETERRQ(PetscObjectComm((PetscObject)nep),1,"The number of initial vectors is larger than ncv");
    196:     BVInsertVecs(nep->V,0,&k,nep->IS,PETSC_TRUE);
    197:     SlepcBasisDestroy_Private(&nep->nini,&nep->IS);
    198:     nep->nini = k;
    199:   }
    200:   PetscLogEventEnd(NEP_SetUp,nep,0,0,0);
    201:   nep->state = NEP_STATE_SETUP;
    202:   return(0);
    203: }

    205: /*@C
    206:    NEPSetInitialSpace - Specify a basis of vectors that constitute the initial
    207:    space, that is, the subspace from which the solver starts to iterate.

    209:    Collective on nep

    211:    Input Parameter:
    212: +  nep   - the nonlinear eigensolver context
    213: .  n     - number of vectors
    214: -  is    - set of basis vectors of the initial space

    216:    Notes:
    217:    Some solvers start to iterate on a single vector (initial vector). In that case,
    218:    the other vectors are ignored.

    220:    These vectors do not persist from one NEPSolve() call to the other, so the
    221:    initial space should be set every time.

    223:    The vectors do not need to be mutually orthonormal, since they are explicitly
    224:    orthonormalized internally.

    226:    Common usage of this function is when the user can provide a rough approximation
    227:    of the wanted eigenspace. Then, convergence may be faster.

    229:    Level: intermediate
    230: @*/
    231: PetscErrorCode NEPSetInitialSpace(NEP nep,PetscInt n,Vec is[])
    232: {

    238:   if (n<0) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"Argument n cannot be negative");
    239:   if (n>0) {
    242:   }
    243:   SlepcBasisReference_Private(n,is,&nep->nini,&nep->IS);
    244:   if (n>0) nep->state = NEP_STATE_INITIAL;
    245:   return(0);
    246: }

    248: /*
    249:   NEPSetDimensions_Default - Set reasonable values for ncv, mpd if not set
    250:   by the user. This is called at setup.
    251:  */
    252: PetscErrorCode NEPSetDimensions_Default(NEP nep,PetscInt nev,PetscInt *ncv,PetscInt *mpd)
    253: {
    255:   if (*ncv!=PETSC_DEFAULT) { /* ncv set */
    256:     if (*ncv<nev) SETERRQ(PetscObjectComm((PetscObject)nep),1,"The value of ncv must be at least nev");
    257:   } else if (*mpd!=PETSC_DEFAULT) { /* mpd set */
    258:     *ncv = PetscMin(nep->n,nev+(*mpd));
    259:   } else { /* neither set: defaults depend on nev being small or large */
    260:     if (nev<500) *ncv = PetscMin(nep->n,PetscMax(2*nev,nev+15));
    261:     else {
    262:       *mpd = 500;
    263:       *ncv = PetscMin(nep->n,nev+(*mpd));
    264:     }
    265:   }
    266:   if (*mpd==PETSC_DEFAULT) *mpd = *ncv;
    267:   return(0);
    268: }

    270: /*@
    271:    NEPAllocateSolution - Allocate memory storage for common variables such
    272:    as eigenvalues and eigenvectors.

    274:    Collective on nep

    276:    Input Parameters:
    277: +  nep   - eigensolver context
    278: -  extra - number of additional positions, used for methods that require a
    279:            working basis slightly larger than ncv

    281:    Developers Note:
    282:    This is SLEPC_EXTERN because it may be required by user plugin NEP
    283:    implementations.

    285:    Level: developer
    286: @*/
    287: PetscErrorCode NEPAllocateSolution(NEP nep,PetscInt extra)
    288: {
    290:   PetscInt       oldsize,newc,requested;
    291:   PetscLogDouble cnt;
    292:   Mat            T;
    293:   Vec            t;

    296:   requested = nep->ncv + extra;

    298:   /* oldsize is zero if this is the first time setup is called */
    299:   BVGetSizes(nep->V,NULL,NULL,&oldsize);
    300:   newc = PetscMax(0,requested-oldsize);

    302:   /* allocate space for eigenvalues and friends */
    303:   if (requested != oldsize || !nep->eigr) {
    304:     PetscFree4(nep->eigr,nep->eigi,nep->errest,nep->perm);
    305:     PetscMalloc4(requested,&nep->eigr,requested,&nep->eigi,requested,&nep->errest,requested,&nep->perm);
    306:     cnt = newc*sizeof(PetscScalar) + newc*sizeof(PetscReal) + newc*sizeof(PetscInt);
    307:     PetscLogObjectMemory((PetscObject)nep,cnt);
    308:   }

    310:   /* allocate V */
    311:   if (!nep->V) { NEPGetBV(nep,&nep->V); }
    312:   if (!oldsize) {
    313:     if (!((PetscObject)(nep->V))->type_name) {
    314:       BVSetType(nep->V,BVSVEC);
    315:     }
    316:     if (nep->fui==NEP_USER_INTERFACE_SPLIT) T = nep->A[0];
    317:     else {
    318:       NEPGetFunction(nep,&T,NULL,NULL,NULL);
    319:     }
    320:     MatCreateVecsEmpty(T,&t,NULL);
    321:     BVSetSizesFromVec(nep->V,t,requested);
    322:     VecDestroy(&t);
    323:   } else {
    324:     BVResize(nep->V,requested,PETSC_FALSE);
    325:   }

    327:   /* allocate W */
    328:   if (nep->twosided) {
    329:     BVDestroy(&nep->W);
    330:     BVDuplicate(nep->V,&nep->W);
    331:   }
    332:   return(0);
    333: }