Date: 2022-03-31T15:29:31+00:00

Actual source code: nepsetup.c
slepc-3.17.0 2022-03-31
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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:    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: {
     36:   PetscInt       k;
     37:   SlepcSC        sc;
     38:   Mat            T;
     39:   PetscBool      flg;
     40:   KSP            ksp;
     41:   PC             pc;
     42:   PetscMPIInt    size;
     43:   MatSolverType  stype;

     46:   NEPCheckProblem(nep,1);
     47:   if (nep->state) PetscFunctionReturn(0);
     48:   PetscLogEventBegin(NEP_SetUp,nep,0,0,0);

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

     53:   /* set default solver type (NEPSetFromOptions was not called) */
     54:   if (!((PetscObject)nep)->type_name) NEPSetType(nep,NEPRII);
     55:   if (nep->useds && !nep->ds) NEPGetDS(nep,&nep->ds);
     56:   if (!nep->rg) NEPGetRG(nep,&nep->rg);
     57:   if (!((PetscObject)nep->rg)->type_name) RGSetType(nep->rg,RGINTERVAL);

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

     80:   /* set default problem type */
     81:   if (!nep->problem_type) NEPSetProblemType(nep,NEP_GENERAL);

     83:   /* check consistency of refinement options */
     84:   if (nep->refine) {
     86:     if (!nep->scheme) {  /* set default scheme */
     87:       NEPRefineGetKSP(nep,&ksp);
     88:       KSPGetPC(ksp,&pc);
     89:       PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
     90:       if (flg) PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
     91:       nep->scheme = flg? NEP_REFINE_SCHEME_MBE: NEP_REFINE_SCHEME_SCHUR;
     92:     }
     93:     if (nep->scheme==NEP_REFINE_SCHEME_MBE) {
     94:       NEPRefineGetKSP(nep,&ksp);
     95:       KSPGetPC(ksp,&pc);
     96:       PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
     97:       if (flg) PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
     99:       MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
    100:       if (size>1) {   /* currently selected PC is a factorization */
    101:         PCFactorGetMatSolverType(pc,&stype);
    102:         PetscStrcmp(stype,MATSOLVERPETSC,&flg);
    104:       }
    105:     }
    106:     if (nep->scheme==NEP_REFINE_SCHEME_SCHUR) {
    108:     }
    109:   }
    110:   /* call specific solver setup */
    111:   (*nep->ops->setup)(nep);

    113:   /* set tolerance if not yet set */
    114:   if (nep->tol==PETSC_DEFAULT) nep->tol = SLEPC_DEFAULT_TOL;
    115:   if (nep->refine) {
    116:     if (nep->rtol==PETSC_DEFAULT) nep->rtol = PetscMax(nep->tol/1000,PETSC_MACHINE_EPSILON);
    117:     if (nep->rits==PETSC_DEFAULT) nep->rits = (nep->refine==NEP_REFINE_SIMPLE)? 10: 1;
    118:   }

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

    168:   nep->sc->map    = NULL;
    169:   nep->sc->mapobj = NULL;

    171:   /* fill sorting criterion for DS */
    172:   if (nep->useds) {
    173:     DSGetSlepcSC(nep->ds,&sc);
    174:     sc->comparison    = nep->sc->comparison;
    175:     sc->comparisonctx = nep->sc->comparisonctx;
    176:     PetscObjectTypeCompare((PetscObject)nep,NEPNLEIGS,&flg);
    177:     if (!flg) {
    178:       sc->map    = NULL;
    179:       sc->mapobj = NULL;
    180:     }
    181:   }

    184:   /* process initial vectors */
    185:   if (nep->nini<0) {
    186:     k = -nep->nini;
    188:     BVInsertVecs(nep->V,0,&k,nep->IS,PETSC_TRUE);
    189:     SlepcBasisDestroy_Private(&nep->nini,&nep->IS);
    190:     nep->nini = k;
    191:   }
    192:   PetscLogEventEnd(NEP_SetUp,nep,0,0,0);
    193:   nep->state = NEP_STATE_SETUP;
    194:   PetscFunctionReturn(0);
    195: }

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

    201:    Collective on nep

    203:    Input Parameters:
    204: +  nep   - the nonlinear eigensolver context
    205: .  n     - number of vectors
    206: -  is    - set of basis vectors of the initial space

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

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

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

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

    221:    Level: intermediate

    223: .seealso: NEPSetUp()
    224: @*/
    225: PetscErrorCode NEPSetInitialSpace(NEP nep,PetscInt n,Vec is[])
    226: {
    230:   if (n>0) {
    233:   }
    234:   SlepcBasisReference_Private(n,is,&nep->nini,&nep->IS);
    235:   if (n>0) nep->state = NEP_STATE_INITIAL;
    236:   PetscFunctionReturn(0);
    237: }

    239: /*
    240:   NEPSetDimensions_Default - Set reasonable values for ncv, mpd if not set
    241:   by the user. This is called at setup.
    242:  */
    243: PetscErrorCode NEPSetDimensions_Default(NEP nep,PetscInt nev,PetscInt *ncv,PetscInt *mpd)
    244: {
    245:   if (*ncv!=PETSC_DEFAULT) { /* ncv set */
    247:   } else if (*mpd!=PETSC_DEFAULT) { /* mpd set */
    248:     *ncv = PetscMin(nep->n,nev+(*mpd));
    249:   } else { /* neither set: defaults depend on nev being small or large */
    250:     if (nev<500) *ncv = PetscMin(nep->n,PetscMax(2*nev,nev+15));
    251:     else {
    252:       *mpd = 500;
    253:       *ncv = PetscMin(nep->n,nev+(*mpd));
    254:     }
    255:   }
    256:   if (*mpd==PETSC_DEFAULT) *mpd = *ncv;
    257:   PetscFunctionReturn(0);
    258: }

    260: /*@
    261:    NEPAllocateSolution - Allocate memory storage for common variables such
    262:    as eigenvalues and eigenvectors.

    264:    Collective on nep

    266:    Input Parameters:
    267: +  nep   - eigensolver context
    268: -  extra - number of additional positions, used for methods that require a
    269:            working basis slightly larger than ncv

    271:    Developer Notes:
    272:    This is SLEPC_EXTERN because it may be required by user plugin NEP
    273:    implementations.

    275:    Level: developer

    277: .seealso: PEPSetUp()
    278: @*/
    279: PetscErrorCode NEPAllocateSolution(NEP nep,PetscInt extra)
    280: {
    281:   PetscInt       oldsize,newc,requested;
    282:   PetscLogDouble cnt;
    283:   PetscRandom    rand;
    284:   Mat            T;
    285:   Vec            t;

    287:   requested = nep->ncv + extra;

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

    293:   /* allocate space for eigenvalues and friends */
    294:   if (requested != oldsize || !nep->eigr) {
    295:     PetscFree4(nep->eigr,nep->eigi,nep->errest,nep->perm);
    296:     PetscMalloc4(requested,&nep->eigr,requested,&nep->eigi,requested,&nep->errest,requested,&nep->perm);
    297:     cnt = newc*sizeof(PetscScalar) + newc*sizeof(PetscReal) + newc*sizeof(PetscInt);
    298:     PetscLogObjectMemory((PetscObject)nep,cnt);
    299:   }

    301:   /* allocate V */
    302:   if (!nep->V) NEPGetBV(nep,&nep->V);
    303:   if (!oldsize) {
    304:     if (!((PetscObject)(nep->V))->type_name) BVSetType(nep->V,BVSVEC);
    305:     if (nep->fui==NEP_USER_INTERFACE_SPLIT) T = nep->A[0];
    306:     else NEPGetFunction(nep,&T,NULL,NULL,NULL);
    307:     MatCreateVecsEmpty(T,&t,NULL);
    308:     BVSetSizesFromVec(nep->V,t,requested);
    309:     VecDestroy(&t);
    310:   } else BVResize(nep->V,requested,PETSC_FALSE);

    312:   /* allocate W */
    313:   if (nep->twosided) {
    314:     BVGetRandomContext(nep->V,&rand);  /* make sure the random context is available when duplicating */
    315:     BVDestroy(&nep->W);
    316:     BVDuplicate(nep->V,&nep->W);
    317:   }
    318:   PetscFunctionReturn(0);
    319: }