1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2021, 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);CHKERRMPI(ierr);
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 NEP283: implementations.
285: Level: developer
286: @*/
287: PetscErrorCode NEPAllocateSolution(NEP nep,PetscInt extra)288: {
290: PetscInt oldsize,newc,requested;
291: PetscLogDouble cnt;
292: PetscRandom rand;
293: Mat T;
294: Vec t;
297: requested = nep->ncv + extra;
299: /* oldsize is zero if this is the first time setup is called */
300: BVGetSizes(nep->V,NULL,NULL,&oldsize);
301: newc = PetscMax(0,requested-oldsize);
303: /* allocate space for eigenvalues and friends */
304: if (requested != oldsize || !nep->eigr) {
305: PetscFree4(nep->eigr,nep->eigi,nep->errest,nep->perm);
306: PetscMalloc4(requested,&nep->eigr,requested,&nep->eigi,requested,&nep->errest,requested,&nep->perm);
307: cnt = newc*sizeof(PetscScalar) + newc*sizeof(PetscReal) + newc*sizeof(PetscInt);
308: PetscLogObjectMemory((PetscObject)nep,cnt);
309: }
311: /* allocate V */
312: if (!nep->V) { NEPGetBV(nep,&nep->V); }
313: if (!oldsize) {
314: if (!((PetscObject)(nep->V))->type_name) {
315: BVSetType(nep->V,BVSVEC);
316: }
317: if (nep->fui==NEP_USER_INTERFACE_SPLIT) T = nep->A[0];
318: else {
319: NEPGetFunction(nep,&T,NULL,NULL,NULL);
320: }
321: MatCreateVecsEmpty(T,&t,NULL);
322: BVSetSizesFromVec(nep->V,t,requested);
323: VecDestroy(&t);
324: } else {
325: BVResize(nep->V,requested,PETSC_FALSE);
326: }
328: /* allocate W */
329: if (nep->twosided) {
330: BVGetRandomContext(nep->V,&rand); /* make sure the random context is available when duplicating */
331: BVDestroy(&nep->W);
332: BVDuplicate(nep->V,&nep->W);
333: }
334: return(0);
335: }