1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2018, 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> /*I "slepcnep.h" I*/
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->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: case NEP_USER_INTERFACE_DERIVATIVES:
81: NEPGetDerivatives(nep,&T,NULL,NULL);
82: MatGetSize(T,&nep->n,NULL);
83: MatGetLocalSize(T,&nep->nloc,NULL);
84: break;
85: }
87: /* set default problem type */
88: if (!nep->problem_type) {
89: NEPSetProblemType(nep,NEP_GENERAL);
90: }
92: /* check consistency of refinement options */
93: if (nep->refine) {
94: if (nep->fui!=NEP_USER_INTERFACE_SPLIT) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"Iterative refinement only implemented in split form");
95: if (!nep->scheme) { /* set default scheme */
96: NEPRefineGetKSP(nep,&ksp);
97: KSPGetPC(ksp,&pc);
98: PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
99: if (flg) {
100: PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
101: }
102: nep->scheme = flg? NEP_REFINE_SCHEME_MBE: NEP_REFINE_SCHEME_SCHUR;
103: }
104: if (nep->scheme==NEP_REFINE_SCHEME_MBE) {
105: NEPRefineGetKSP(nep,&ksp);
106: KSPGetPC(ksp,&pc);
107: PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
108: if (flg) {
109: PetscObjectTypeCompareAny((PetscObject)pc,&flg,PCLU,PCCHOLESKY,"");
110: }
111: if (!flg) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"The MBE scheme for refinement requires a direct solver in KSP");
112: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
113: if (size>1) { /* currently selected PC is a factorization */
114: PCFactorGetMatSolverType(pc,&stype);
115: PetscStrcmp(stype,MATSOLVERPETSC,&flg);
116: 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");
117: }
118: }
119: if (nep->scheme==NEP_REFINE_SCHEME_SCHUR) {
120: if (nep->npart>1) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"The Schur scheme for refinement does not support subcommunicators");
121: }
122: }
123: /* call specific solver setup */
124: (*nep->ops->setup)(nep);
126: /* by default, compute eigenvalues close to target */
127: /* nep->target should contain the initial guess for the eigenvalue */
128: if (!nep->which) nep->which = NEP_TARGET_MAGNITUDE;
130: /* set tolerance if not yet set */
131: if (nep->tol==PETSC_DEFAULT) nep->tol = SLEPC_DEFAULT_TOL;
132: if (nep->refine) {
133: if (nep->rtol==PETSC_DEFAULT) nep->rtol = PetscMax(nep->tol/1000,PETSC_MACHINE_EPSILON);
134: if (nep->rits==PETSC_DEFAULT) nep->rits = (nep->refine==NEP_REFINE_SIMPLE)? 10: 1;
135: }
137: /* fill sorting criterion context */
138: switch (nep->which) {
139: case NEP_LARGEST_MAGNITUDE:
140: nep->sc->comparison = SlepcCompareLargestMagnitude;
141: nep->sc->comparisonctx = NULL;
142: break;
143: case NEP_SMALLEST_MAGNITUDE:
144: nep->sc->comparison = SlepcCompareSmallestMagnitude;
145: nep->sc->comparisonctx = NULL;
146: break;
147: case NEP_LARGEST_REAL:
148: nep->sc->comparison = SlepcCompareLargestReal;
149: nep->sc->comparisonctx = NULL;
150: break;
151: case NEP_SMALLEST_REAL:
152: nep->sc->comparison = SlepcCompareSmallestReal;
153: nep->sc->comparisonctx = NULL;
154: break;
155: case NEP_LARGEST_IMAGINARY:
156: nep->sc->comparison = SlepcCompareLargestImaginary;
157: nep->sc->comparisonctx = NULL;
158: break;
159: case NEP_SMALLEST_IMAGINARY:
160: nep->sc->comparison = SlepcCompareSmallestImaginary;
161: nep->sc->comparisonctx = NULL;
162: break;
163: case NEP_TARGET_MAGNITUDE:
164: nep->sc->comparison = SlepcCompareTargetMagnitude;
165: nep->sc->comparisonctx = &nep->target;
166: break;
167: case NEP_TARGET_REAL:
168: nep->sc->comparison = SlepcCompareTargetReal;
169: nep->sc->comparisonctx = &nep->target;
170: break;
171: case NEP_TARGET_IMAGINARY:
172: #if defined(PETSC_USE_COMPLEX)
173: nep->sc->comparison = SlepcCompareTargetImaginary;
174: nep->sc->comparisonctx = &nep->target;
175: #endif
176: break;
177: case NEP_ALL:
178: nep->sc->comparison = SlepcCompareSmallestReal;
179: nep->sc->comparisonctx = NULL;
180: break;
181: case NEP_WHICH_USER:
182: break;
183: }
185: nep->sc->map = NULL;
186: nep->sc->mapobj = NULL;
188: /* fill sorting criterion for DS */
189: DSGetSlepcSC(nep->ds,&sc);
190: sc->comparison = nep->sc->comparison;
191: sc->comparisonctx = nep->sc->comparisonctx;
192: PetscObjectTypeCompare((PetscObject)nep,NEPNLEIGS,&flg);
193: if (!flg) {
194: sc->map = NULL;
195: sc->mapobj = NULL;
196: }
197: if (nep->ncv > nep->n) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"ncv must be the problem size at most");
198: if (nep->nev > nep->ncv) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"nev bigger than ncv");
200: /* process initial vectors */
201: if (nep->nini<0) {
202: k = -nep->nini;
203: if (k>nep->ncv) SETERRQ(PetscObjectComm((PetscObject)nep),1,"The number of initial vectors is larger than ncv");
204: BVInsertVecs(nep->V,0,&k,nep->IS,PETSC_TRUE);
205: SlepcBasisDestroy_Private(&nep->nini,&nep->IS);
206: nep->nini = k;
207: }
208: PetscLogEventEnd(NEP_SetUp,nep,0,0,0);
209: nep->state = NEP_STATE_SETUP;
210: return(0);
211: }
213: /*@C
214: NEPSetInitialSpace - Specify a basis of vectors that constitute the initial
215: space, that is, the subspace from which the solver starts to iterate.
217: Collective on NEP and Vec
219: Input Parameter:
220: + nep - the nonlinear eigensolver context
221: . n - number of vectors
222: - is - set of basis vectors of the initial space
224: Notes:
225: Some solvers start to iterate on a single vector (initial vector). In that case,
226: the other vectors are ignored.
228: These vectors do not persist from one NEPSolve() call to the other, so the
229: initial space should be set every time.
231: The vectors do not need to be mutually orthonormal, since they are explicitly
232: orthonormalized internally.
234: Common usage of this function is when the user can provide a rough approximation
235: of the wanted eigenspace. Then, convergence may be faster.
237: Level: intermediate
238: @*/
239: PetscErrorCode NEPSetInitialSpace(NEP nep,PetscInt n,Vec *is)240: {
246: if (n<0) SETERRQ(PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"Argument n cannot be negative");
247: SlepcBasisReference_Private(n,is,&nep->nini,&nep->IS);
248: if (n>0) nep->state = NEP_STATE_INITIAL;
249: return(0);
250: }
252: /*
253: NEPSetDimensions_Default - Set reasonable values for ncv, mpd if not set
254: by the user. This is called at setup.
255: */
256: PetscErrorCode NEPSetDimensions_Default(NEP nep,PetscInt nev,PetscInt *ncv,PetscInt *mpd)257: {
259: if (*ncv) { /* ncv set */
260: if (*ncv<nev) SETERRQ(PetscObjectComm((PetscObject)nep),1,"The value of ncv must be at least nev");
261: } else if (*mpd) { /* mpd set */
262: *ncv = PetscMin(nep->n,nev+(*mpd));
263: } else { /* neither set: defaults depend on nev being small or large */
264: if (nev<500) *ncv = PetscMin(nep->n,PetscMax(2*nev,nev+15));
265: else {
266: *mpd = 500;
267: *ncv = PetscMin(nep->n,nev+(*mpd));
268: }
269: }
270: if (!*mpd) *mpd = *ncv;
271: return(0);
272: }
274: /*@
275: NEPAllocateSolution - Allocate memory storage for common variables such
276: as eigenvalues and eigenvectors.
278: Collective on NEP280: Input Parameters:
281: + nep - eigensolver context
282: - extra - number of additional positions, used for methods that require a
283: working basis slightly larger than ncv
285: Developers Note:
286: This is PETSC_EXTERN because it may be required by user plugin NEP287: implementations.
289: Level: developer
290: @*/
291: PetscErrorCode NEPAllocateSolution(NEP nep,PetscInt extra)292: {
294: PetscInt oldsize,newc,requested;
295: PetscLogDouble cnt;
296: Mat T;
297: Vec t;
300: requested = nep->ncv + extra;
302: /* oldsize is zero if this is the first time setup is called */
303: BVGetSizes(nep->V,NULL,NULL,&oldsize);
304: newc = PetscMax(0,requested-oldsize);
306: /* allocate space for eigenvalues and friends */
307: if (requested != oldsize || !nep->eigr) {
308: PetscFree4(nep->eigr,nep->eigi,nep->errest,nep->perm);
309: PetscMalloc4(requested,&nep->eigr,requested,&nep->eigi,requested,&nep->errest,requested,&nep->perm);
310: cnt = newc*sizeof(PetscScalar) + newc*sizeof(PetscReal) + newc*sizeof(PetscInt);
311: PetscLogObjectMemory((PetscObject)nep,cnt);
312: }
314: /* allocate V */
315: if (!nep->V) { NEPGetBV(nep,&nep->V); }
316: if (!oldsize) {
317: if (!((PetscObject)(nep->V))->type_name) {
318: BVSetType(nep->V,BVSVEC);
319: }
320: if (nep->fui==NEP_USER_INTERFACE_SPLIT) T = nep->A[0];
321: else {
322: NEPGetFunction(nep,&T,NULL,NULL,NULL);
323: }
324: MatCreateVecsEmpty(T,&t,NULL);
325: BVSetSizesFromVec(nep->V,t,requested);
326: VecDestroy(&t);
327: } else {
328: BVResize(nep->V,requested,PETSC_FALSE);
329: }
330: return(0);
331: }