Actual source code: nepsetup.c

slepc-3.18.0 2022-10-01
Report Typos and Errors
  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) return 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:     if (nep->P) MatDuplicate(nep->P[0],MAT_DO_NOT_COPY_VALUES,&nep->function_pre);
 69:     MatDuplicate(nep->A[0],MAT_DO_NOT_COPY_VALUES,&nep->jacobian);
 70:     MatGetSize(nep->A[0],&nep->n,NULL);
 71:     MatGetLocalSize(nep->A[0],&nep->nloc,NULL);
 72:     break;
 73:   }

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

 78:   /* check consistency of refinement options */
 79:   if (nep->refine) {
 81:     if (!nep->scheme) {  /* set default scheme */
 82:       NEPRefineGetKSP(nep,&ksp);
 83:       KSPGetPC(ksp,&pc);
 84:       PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
 85:       if (flg) PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
 86:       nep->scheme = flg? NEP_REFINE_SCHEME_MBE: NEP_REFINE_SCHEME_SCHUR;
 87:     }
 88:     if (nep->scheme==NEP_REFINE_SCHEME_MBE) {
 89:       NEPRefineGetKSP(nep,&ksp);
 90:       KSPGetPC(ksp,&pc);
 91:       PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
 92:       if (flg) PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
 94:       MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
 95:       if (size>1) {   /* currently selected PC is a factorization */
 96:         PCFactorGetMatSolverType(pc,&stype);
 97:         PetscStrcmp(stype,MATSOLVERPETSC,&flg);
 99:       }
100:     }
101:     if (nep->scheme==NEP_REFINE_SCHEME_SCHUR) {
103:     }
104:   }
105:   /* call specific solver setup */
106:   PetscUseTypeMethod(nep,setup);

108:   /* set tolerance if not yet set */
109:   if (nep->tol==PETSC_DEFAULT) nep->tol = SLEPC_DEFAULT_TOL;
110:   if (nep->refine) {
111:     if (nep->rtol==PETSC_DEFAULT) nep->rtol = PetscMax(nep->tol/1000,PETSC_MACHINE_EPSILON);
112:     if (nep->rits==PETSC_DEFAULT) nep->rits = (nep->refine==NEP_REFINE_SIMPLE)? 10: 1;
113:   }

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

163:   nep->sc->map    = NULL;
164:   nep->sc->mapobj = NULL;

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

179:   /* process initial vectors */
180:   if (nep->nini<0) {
181:     k = -nep->nini;
183:     BVInsertVecs(nep->V,0,&k,nep->IS,PETSC_TRUE);
184:     SlepcBasisDestroy_Private(&nep->nini,&nep->IS);
185:     nep->nini = k;
186:   }
187:   PetscLogEventEnd(NEP_SetUp,nep,0,0,0);
188:   nep->state = NEP_STATE_SETUP;
189:   return 0;
190: }

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

196:    Collective on nep

198:    Input Parameters:
199: +  nep   - the nonlinear eigensolver context
200: .  n     - number of vectors
201: -  is    - set of basis vectors of the initial space

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

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

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

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

216:    Level: intermediate

218: .seealso: NEPSetUp()
219: @*/
220: PetscErrorCode NEPSetInitialSpace(NEP nep,PetscInt n,Vec is[])
221: {
225:   if (n>0) {
228:   }
229:   SlepcBasisReference_Private(n,is,&nep->nini,&nep->IS);
230:   if (n>0) nep->state = NEP_STATE_INITIAL;
231:   return 0;
232: }

234: /*
235:   NEPSetDimensions_Default - Set reasonable values for ncv, mpd if not set
236:   by the user. This is called at setup.
237:  */
238: PetscErrorCode NEPSetDimensions_Default(NEP nep,PetscInt nev,PetscInt *ncv,PetscInt *mpd)
239: {
240:   if (*ncv!=PETSC_DEFAULT) { /* ncv set */
242:   } else if (*mpd!=PETSC_DEFAULT) { /* mpd set */
243:     *ncv = PetscMin(nep->n,nev+(*mpd));
244:   } else { /* neither set: defaults depend on nev being small or large */
245:     if (nev<500) *ncv = PetscMin(nep->n,PetscMax(2*nev,nev+15));
246:     else {
247:       *mpd = 500;
248:       *ncv = PetscMin(nep->n,nev+(*mpd));
249:     }
250:   }
251:   if (*mpd==PETSC_DEFAULT) *mpd = *ncv;
252:   return 0;
253: }

255: /*@
256:    NEPAllocateSolution - Allocate memory storage for common variables such
257:    as eigenvalues and eigenvectors.

259:    Collective on nep

261:    Input Parameters:
262: +  nep   - eigensolver context
263: -  extra - number of additional positions, used for methods that require a
264:            working basis slightly larger than ncv

266:    Developer Notes:
267:    This is SLEPC_EXTERN because it may be required by user plugin NEP
268:    implementations.

270:    Level: developer

272: .seealso: PEPSetUp()
273: @*/
274: PetscErrorCode NEPAllocateSolution(NEP nep,PetscInt extra)
275: {
276:   PetscInt       oldsize,requested;
277:   PetscRandom    rand;
278:   Mat            T;
279:   Vec            t;

281:   requested = nep->ncv + extra;

283:   /* oldsize is zero if this is the first time setup is called */
284:   BVGetSizes(nep->V,NULL,NULL,&oldsize);

286:   /* allocate space for eigenvalues and friends */
287:   if (requested != oldsize || !nep->eigr) {
288:     PetscFree4(nep->eigr,nep->eigi,nep->errest,nep->perm);
289:     PetscMalloc4(requested,&nep->eigr,requested,&nep->eigi,requested,&nep->errest,requested,&nep->perm);
290:   }

292:   /* allocate V */
293:   if (!nep->V) NEPGetBV(nep,&nep->V);
294:   if (!oldsize) {
295:     if (!((PetscObject)(nep->V))->type_name) BVSetType(nep->V,BVSVEC);
296:     if (nep->fui==NEP_USER_INTERFACE_SPLIT) T = nep->A[0];
297:     else NEPGetFunction(nep,&T,NULL,NULL,NULL);
298:     MatCreateVecsEmpty(T,&t,NULL);
299:     BVSetSizesFromVec(nep->V,t,requested);
300:     VecDestroy(&t);
301:   } else BVResize(nep->V,requested,PETSC_FALSE);

303:   /* allocate W */
304:   if (nep->twosided) {
305:     BVGetRandomContext(nep->V,&rand);  /* make sure the random context is available when duplicating */
306:     BVDestroy(&nep->W);
307:     BVDuplicate(nep->V,&nep->W);
308:   }
309:   return 0;
310: }