Actual source code: svdsetup.c
slepc-3.21.0 2024-03-30
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: SVD routines for setting up the solver
12: */
14: #include <slepc/private/svdimpl.h>
16: /*@
17: SVDSetOperators - Set the matrices associated with the singular value problem.
19: Collective
21: Input Parameters:
22: + svd - the singular value solver context
23: . A - the matrix associated with the singular value problem
24: - B - the second matrix in the case of GSVD
26: Level: beginner
28: .seealso: SVDSolve(), SVDGetOperators()
29: @*/
30: PetscErrorCode SVDSetOperators(SVD svd,Mat A,Mat B)
31: {
32: PetscInt Ma,Na,Mb,Nb,ma,na,mb,nb,M0,N0,m0,n0;
33: PetscBool samesize=PETSC_TRUE;
35: PetscFunctionBegin;
39: PetscCheckSameComm(svd,1,A,2);
40: if (B) PetscCheckSameComm(svd,1,B,3);
42: /* Check matrix sizes */
43: PetscCall(MatGetSize(A,&Ma,&Na));
44: PetscCall(MatGetLocalSize(A,&ma,&na));
45: if (svd->OP) {
46: PetscCall(MatGetSize(svd->OP,&M0,&N0));
47: PetscCall(MatGetLocalSize(svd->OP,&m0,&n0));
48: if (M0!=Ma || N0!=Na || m0!=ma || n0!=na) samesize = PETSC_FALSE;
49: }
50: if (B) {
51: PetscCall(MatGetSize(B,&Mb,&Nb));
52: PetscCall(MatGetLocalSize(B,&mb,&nb));
53: PetscCheck(Na==Nb,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_WRONG,"Different number of columns in A (%" PetscInt_FMT ") and B (%" PetscInt_FMT ")",Na,Nb);
54: PetscCheck(na==nb,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_WRONG,"Different local column size in A (%" PetscInt_FMT ") and B (%" PetscInt_FMT ")",na,nb);
55: if (svd->OPb) {
56: PetscCall(MatGetSize(svd->OPb,&M0,&N0));
57: PetscCall(MatGetLocalSize(svd->OPb,&m0,&n0));
58: if (M0!=Mb || N0!=Nb || m0!=mb || n0!=nb) samesize = PETSC_FALSE;
59: }
60: }
62: PetscCall(PetscObjectReference((PetscObject)A));
63: if (B) PetscCall(PetscObjectReference((PetscObject)B));
64: if (svd->state && !samesize) PetscCall(SVDReset(svd));
65: else {
66: PetscCall(MatDestroy(&svd->OP));
67: PetscCall(MatDestroy(&svd->OPb));
68: PetscCall(MatDestroy(&svd->A));
69: PetscCall(MatDestroy(&svd->B));
70: PetscCall(MatDestroy(&svd->AT));
71: PetscCall(MatDestroy(&svd->BT));
72: }
73: svd->nrma = 0.0;
74: svd->nrmb = 0.0;
75: svd->OP = A;
76: svd->OPb = B;
77: svd->state = SVD_STATE_INITIAL;
78: PetscFunctionReturn(PETSC_SUCCESS);
79: }
81: /*@
82: SVDGetOperators - Get the matrices associated with the singular value problem.
84: Not Collective
86: Input Parameter:
87: . svd - the singular value solver context
89: Output Parameters:
90: + A - the matrix associated with the singular value problem
91: - B - the second matrix in the case of GSVD
93: Level: intermediate
95: .seealso: SVDSolve(), SVDSetOperators()
96: @*/
97: PetscErrorCode SVDGetOperators(SVD svd,Mat *A,Mat *B)
98: {
99: PetscFunctionBegin;
101: if (A) *A = svd->OP;
102: if (B) *B = svd->OPb;
103: PetscFunctionReturn(PETSC_SUCCESS);
104: }
106: /*@
107: SVDSetSignature - Set the signature matrix defining a hyperbolic singular value problem.
109: Collective
111: Input Parameters:
112: + svd - the singular value solver context
113: - omega - a vector containing the diagonal elements of the signature matrix (or NULL)
115: Notes:
116: The signature matrix is relevant only for hyperbolic problems (HSVD).
117: Use NULL to reset a previously set signature.
119: Level: intermediate
121: .seealso: SVDSetProblemType(), SVDSetOperators(), SVDGetSignature()
122: @*/
123: PetscErrorCode SVDSetSignature(SVD svd,Vec omega)
124: {
125: PetscInt N,Ma,n,ma;
127: PetscFunctionBegin;
129: if (omega) {
131: PetscCheckSameComm(svd,1,omega,2);
132: }
134: if (omega && svd->OP) { /* Check sizes */
135: PetscCall(VecGetSize(omega,&N));
136: PetscCall(VecGetLocalSize(omega,&n));
137: PetscCall(MatGetSize(svd->OP,&Ma,NULL));
138: PetscCall(MatGetLocalSize(svd->OP,&ma,NULL));
139: PetscCheck(N==Ma,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_SIZ,"Global size of signature (%" PetscInt_FMT ") does not match the row size of A (%" PetscInt_FMT ")",N,Ma);
140: PetscCheck(n==ma,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_SIZ,"Local size of signature (%" PetscInt_FMT ") does not match the local row size of A (%" PetscInt_FMT ")",n,ma);
141: }
143: PetscCall(VecDestroy(&svd->omega));
144: if (omega) {
145: PetscCall(VecDuplicate(omega,&svd->omega));
146: PetscCall(VecCopy(omega,svd->omega));
147: }
148: svd->state = SVD_STATE_INITIAL;
149: PetscFunctionReturn(PETSC_SUCCESS);
150: }
152: /*@
153: SVDGetSignature - Get the signature matrix defining a hyperbolic singular value problem.
155: Not Collective
157: Input Parameter:
158: . svd - the singular value solver context
160: Output Parameter:
161: . omega - a vector containing the diagonal elements of the signature matrix
163: Notes:
164: The signature matrix is relevant only for hyperbolic problems (HSVD).
165: If no signature has been set, this function will return a vector of all ones.
167: The user should pass a previously created Vec with the appropriate dimension.
169: Level: intermediate
171: .seealso: SVDSetSignature()
172: @*/
173: PetscErrorCode SVDGetSignature(SVD svd,Vec omega)
174: {
175: PetscFunctionBegin;
178: if (svd->omega) PetscCall(VecCopy(svd->omega,omega));
179: else PetscCall(VecSet(omega,1.0));
180: PetscFunctionReturn(PETSC_SUCCESS);
181: }
183: /*@
184: SVDSetDSType - Sets the type of the internal DS object based on the current
185: settings of the singular value solver.
187: Collective
189: Input Parameter:
190: . svd - singular value solver context
192: Note:
193: This function need not be called explicitly, since it will be called at
194: both SVDSetFromOptions() and SVDSetUp().
196: Level: developer
198: .seealso: SVDSetFromOptions(), SVDSetUp()
199: @*/
200: PetscErrorCode SVDSetDSType(SVD svd)
201: {
202: PetscFunctionBegin;
204: PetscTryTypeMethod(svd,setdstype);
205: PetscFunctionReturn(PETSC_SUCCESS);
206: }
208: /*@
209: SVDSetUp - Sets up all the internal data structures necessary for the
210: execution of the singular value solver.
212: Collective
214: Input Parameter:
215: . svd - singular value solver context
217: Notes:
218: This function need not be called explicitly in most cases, since SVDSolve()
219: calls it. It can be useful when one wants to measure the set-up time
220: separately from the solve time.
222: Level: developer
224: .seealso: SVDCreate(), SVDSolve(), SVDDestroy()
225: @*/
226: PetscErrorCode SVDSetUp(SVD svd)
227: {
228: PetscBool flg;
229: PetscInt M,N,P=0,k,maxnsol,m,Nom,nom;
230: SlepcSC sc;
231: Vec *T;
232: BV bv;
234: PetscFunctionBegin;
236: if (svd->state) PetscFunctionReturn(PETSC_SUCCESS);
237: PetscCall(PetscLogEventBegin(SVD_SetUp,svd,0,0,0));
239: /* reset the convergence flag from the previous solves */
240: svd->reason = SVD_CONVERGED_ITERATING;
242: /* set default solver type (SVDSetFromOptions was not called) */
243: if (!((PetscObject)svd)->type_name) PetscCall(SVDSetType(svd,SVDCROSS));
244: if (!svd->ds) PetscCall(SVDGetDS(svd,&svd->ds));
246: /* check matrices */
247: PetscCheck(svd->OP,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_WRONGSTATE,"SVDSetOperators() must be called first");
249: if (!svd->problem_type) { /* set default problem type */
250: if (svd->OPb) {
251: PetscCheck(!svd->omega,PetscObjectComm((PetscObject)svd),PETSC_ERR_SUP,"There is no support yet for generalized hyperbolic problems");
252: PetscCall(SVDSetProblemType(svd,SVD_GENERALIZED));
253: } else {
254: if (svd->omega) PetscCall(SVDSetProblemType(svd,SVD_HYPERBOLIC));
255: else PetscCall(SVDSetProblemType(svd,SVD_STANDARD));
256: }
257: } else { /* check consistency of problem type set by user */
258: if (svd->OPb) {
259: PetscCheck(svd->isgeneralized,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_INCOMP,"Inconsistent SVD state: the problem type does not match the number of matrices");
260: PetscCheck(!svd->omega,PetscObjectComm((PetscObject)svd),PETSC_ERR_SUP,"There is no support yet for generalized hyperbolic problems");
261: } else {
262: PetscCheck(!svd->isgeneralized,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_INCOMP,"Inconsistent SVD state: the problem type does not match the number of matrices");
263: if (svd->omega) PetscCheck(svd->ishyperbolic,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_INCOMP,"Inconsistent SVD state: the problem type must be set to hyperbolic when passing a signature with SVDSetSignature()");
264: else PetscCheck(!svd->ishyperbolic,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_INCOMP,"Inconsistent SVD state: a hyperbolic problem requires passing a signature with SVDSetSignature()");
265: }
266: }
268: /* set DS type once the default problem type has been determined */
269: PetscCall(SVDSetDSType(svd));
271: /* determine how to handle the transpose */
272: svd->expltrans = PETSC_TRUE;
273: if (svd->impltrans) svd->expltrans = PETSC_FALSE;
274: else {
275: PetscCall(MatHasOperation(svd->OP,MATOP_TRANSPOSE,&flg));
276: if (!flg) svd->expltrans = PETSC_FALSE;
277: else {
278: PetscCall(PetscObjectTypeCompareAny((PetscObject)svd,&flg,SVDLAPACK,SVDSCALAPACK,SVDKSVD,SVDELEMENTAL,""));
279: if (flg) svd->expltrans = PETSC_FALSE;
280: }
281: }
283: /* get matrix dimensions */
284: PetscCall(MatGetSize(svd->OP,&M,&N));
285: if (svd->isgeneralized) {
286: PetscCall(MatGetSize(svd->OPb,&P,NULL));
287: PetscCheck(M+P>=N,PetscObjectComm((PetscObject)svd),PETSC_ERR_SUP,"The case when [A;B] has less rows than columns is not supported");
288: } else if (svd->ishyperbolic) {
289: PetscCall(VecGetSize(svd->omega,&Nom));
290: PetscCall(VecGetLocalSize(svd->omega,&nom));
291: PetscCall(MatGetLocalSize(svd->OP,&m,NULL));
292: PetscCheck(Nom==M,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_SIZ,"Global size of signature (%" PetscInt_FMT ") does not match the row size of A (%" PetscInt_FMT ")",Nom,M);
293: PetscCheck(nom==m,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_SIZ,"Local size of signature (%" PetscInt_FMT ") does not match the local row size of A (%" PetscInt_FMT ")",nom,m);
294: }
296: /* build transpose matrix */
297: PetscCall(MatDestroy(&svd->A));
298: PetscCall(MatDestroy(&svd->AT));
299: PetscCall(PetscObjectReference((PetscObject)svd->OP));
300: if (svd->expltrans) {
301: if (svd->isgeneralized || M>=N) {
302: svd->A = svd->OP;
303: PetscCall(MatHermitianTranspose(svd->OP,MAT_INITIAL_MATRIX,&svd->AT));
304: } else {
305: PetscCall(MatHermitianTranspose(svd->OP,MAT_INITIAL_MATRIX,&svd->A));
306: svd->AT = svd->OP;
307: }
308: } else {
309: if (svd->isgeneralized || M>=N) {
310: svd->A = svd->OP;
311: PetscCall(MatCreateHermitianTranspose(svd->OP,&svd->AT));
312: } else {
313: PetscCall(MatCreateHermitianTranspose(svd->OP,&svd->A));
314: svd->AT = svd->OP;
315: }
316: }
318: /* build transpose matrix B for GSVD */
319: if (svd->isgeneralized) {
320: PetscCall(MatDestroy(&svd->B));
321: PetscCall(MatDestroy(&svd->BT));
322: PetscCall(PetscObjectReference((PetscObject)svd->OPb));
323: if (svd->expltrans) {
324: svd->B = svd->OPb;
325: PetscCall(MatHermitianTranspose(svd->OPb,MAT_INITIAL_MATRIX,&svd->BT));
326: } else {
327: svd->B = svd->OPb;
328: PetscCall(MatCreateHermitianTranspose(svd->OPb,&svd->BT));
329: }
330: }
332: if (!svd->isgeneralized && M<N) {
333: /* swap initial vectors */
334: if (svd->nini || svd->ninil) {
335: T=svd->ISL; svd->ISL=svd->IS; svd->IS=T;
336: k=svd->ninil; svd->ninil=svd->nini; svd->nini=k;
337: }
338: /* swap basis vectors */
339: if (!svd->swapped) { /* only the first time in case of multiple calls */
340: bv=svd->V; svd->V=svd->U; svd->U=bv;
341: svd->swapped = PETSC_TRUE;
342: }
343: }
345: maxnsol = svd->isgeneralized? PetscMin(PetscMin(M,N),P): PetscMin(M,N);
346: svd->ncv = PetscMin(svd->ncv,maxnsol);
347: svd->nsv = PetscMin(svd->nsv,maxnsol);
348: PetscCheck(svd->ncv==PETSC_DEFAULT || svd->nsv<=svd->ncv,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_OUTOFRANGE,"nsv bigger than ncv");
350: /* relative convergence criterion is not allowed in GSVD */
351: if (svd->conv==(SVDConv)-1) PetscCall(SVDSetConvergenceTest(svd,svd->isgeneralized?SVD_CONV_NORM:SVD_CONV_REL));
352: PetscCheck(!svd->isgeneralized || svd->conv!=SVD_CONV_REL,PetscObjectComm((PetscObject)svd),PETSC_ERR_SUP,"Relative convergence criterion is not allowed in GSVD");
354: /* initialization of matrix norm (stardard case only, for GSVD it is done inside setup()) */
355: if (!svd->isgeneralized && svd->conv==SVD_CONV_NORM && !svd->nrma) PetscCall(MatNorm(svd->OP,NORM_INFINITY,&svd->nrma));
357: /* call specific solver setup */
358: PetscUseTypeMethod(svd,setup);
360: /* set tolerance if not yet set */
361: if (svd->tol==(PetscReal)PETSC_DEFAULT) svd->tol = SLEPC_DEFAULT_TOL;
363: /* fill sorting criterion context */
364: PetscCall(DSGetSlepcSC(svd->ds,&sc));
365: sc->comparison = (svd->which==SVD_LARGEST)? SlepcCompareLargestReal: SlepcCompareSmallestReal;
366: sc->comparisonctx = NULL;
367: sc->map = NULL;
368: sc->mapobj = NULL;
370: /* process initial vectors */
371: if (svd->nini<0) {
372: k = -svd->nini;
373: PetscCheck(k<=svd->ncv,PetscObjectComm((PetscObject)svd),PETSC_ERR_USER_INPUT,"The number of initial vectors is larger than ncv");
374: PetscCall(BVInsertVecs(svd->V,0,&k,svd->IS,PETSC_TRUE));
375: PetscCall(SlepcBasisDestroy_Private(&svd->nini,&svd->IS));
376: svd->nini = k;
377: }
378: if (svd->ninil<0) {
379: k = 0;
380: if (svd->leftbasis) {
381: k = -svd->ninil;
382: PetscCheck(k<=svd->ncv,PetscObjectComm((PetscObject)svd),PETSC_ERR_USER_INPUT,"The number of left initial vectors is larger than ncv");
383: PetscCall(BVInsertVecs(svd->U,0,&k,svd->ISL,PETSC_TRUE));
384: } else PetscCall(PetscInfo(svd,"Ignoring initial left vectors\n"));
385: PetscCall(SlepcBasisDestroy_Private(&svd->ninil,&svd->ISL));
386: svd->ninil = k;
387: }
389: PetscCall(PetscLogEventEnd(SVD_SetUp,svd,0,0,0));
390: svd->state = SVD_STATE_SETUP;
391: PetscFunctionReturn(PETSC_SUCCESS);
392: }
394: /*@C
395: SVDSetInitialSpaces - Specify two basis of vectors that constitute the initial
396: right and/or left spaces.
398: Collective
400: Input Parameters:
401: + svd - the singular value solver context
402: . nr - number of right vectors
403: . isr - set of basis vectors of the right initial space
404: . nl - number of left vectors
405: - isl - set of basis vectors of the left initial space
407: Notes:
408: The initial right and left spaces are rough approximations to the right and/or
409: left singular subspaces from which the solver starts to iterate.
410: It is not necessary to provide both sets of vectors.
412: Some solvers start to iterate on a single vector (initial vector). In that case,
413: the other vectors are ignored.
415: These vectors do not persist from one SVDSolve() call to the other, so the
416: initial space should be set every time.
418: The vectors do not need to be mutually orthonormal, since they are explicitly
419: orthonormalized internally.
421: Common usage of this function is when the user can provide a rough approximation
422: of the wanted singular space. Then, convergence may be faster.
424: Level: intermediate
426: .seealso: SVDSetUp()
427: @*/
428: PetscErrorCode SVDSetInitialSpaces(SVD svd,PetscInt nr,Vec isr[],PetscInt nl,Vec isl[])
429: {
430: PetscFunctionBegin;
434: PetscCheck(nr>=0,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_OUTOFRANGE,"Argument nr cannot be negative");
435: if (nr>0) {
436: PetscAssertPointer(isr,3);
438: }
439: PetscCheck(nl>=0,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_OUTOFRANGE,"Argument nl cannot be negative");
440: if (nl>0) {
441: PetscAssertPointer(isl,5);
443: }
444: PetscCall(SlepcBasisReference_Private(nr,isr,&svd->nini,&svd->IS));
445: PetscCall(SlepcBasisReference_Private(nl,isl,&svd->ninil,&svd->ISL));
446: if (nr>0 || nl>0) svd->state = SVD_STATE_INITIAL;
447: PetscFunctionReturn(PETSC_SUCCESS);
448: }
450: /*
451: SVDSetDimensions_Default - Set reasonable values for ncv, mpd if not set
452: by the user. This is called at setup.
453: */
454: PetscErrorCode SVDSetDimensions_Default(SVD svd)
455: {
456: PetscInt N,M,P,maxnsol;
458: PetscFunctionBegin;
459: PetscCall(MatGetSize(svd->OP,&M,&N));
460: maxnsol = PetscMin(M,N);
461: if (svd->isgeneralized) {
462: PetscCall(MatGetSize(svd->OPb,&P,NULL));
463: maxnsol = PetscMin(maxnsol,P);
464: }
465: if (svd->ncv!=PETSC_DEFAULT) { /* ncv set */
466: PetscCheck(svd->ncv>=svd->nsv,PetscObjectComm((PetscObject)svd),PETSC_ERR_USER_INPUT,"The value of ncv must be at least nsv");
467: } else if (svd->mpd!=PETSC_DEFAULT) { /* mpd set */
468: svd->ncv = PetscMin(maxnsol,svd->nsv+svd->mpd);
469: } else { /* neither set: defaults depend on nsv being small or large */
470: if (svd->nsv<500) svd->ncv = PetscMin(maxnsol,PetscMax(2*svd->nsv,10));
471: else {
472: svd->mpd = 500;
473: svd->ncv = PetscMin(maxnsol,svd->nsv+svd->mpd);
474: }
475: }
476: if (svd->mpd==PETSC_DEFAULT) svd->mpd = svd->ncv;
477: PetscFunctionReturn(PETSC_SUCCESS);
478: }
480: /*@
481: SVDAllocateSolution - Allocate memory storage for common variables such
482: as the singular values and the basis vectors.
484: Collective
486: Input Parameters:
487: + svd - eigensolver context
488: - extra - number of additional positions, used for methods that require a
489: working basis slightly larger than ncv
491: Developer Notes:
492: This is SLEPC_EXTERN because it may be required by user plugin SVD
493: implementations.
495: This is called at setup after setting the value of ncv and the flag leftbasis.
497: Level: developer
499: .seealso: SVDSetUp()
500: @*/
501: PetscErrorCode SVDAllocateSolution(SVD svd,PetscInt extra)
502: {
503: PetscInt oldsize,requested;
504: Vec tr,tl;
506: PetscFunctionBegin;
507: requested = svd->ncv + extra;
509: /* oldsize is zero if this is the first time setup is called */
510: PetscCall(BVGetSizes(svd->V,NULL,NULL,&oldsize));
512: /* allocate sigma */
513: if (requested != oldsize || !svd->sigma) {
514: PetscCall(PetscFree3(svd->sigma,svd->perm,svd->errest));
515: if (svd->sign) PetscCall(PetscFree(svd->sign));
516: PetscCall(PetscMalloc3(requested,&svd->sigma,requested,&svd->perm,requested,&svd->errest));
517: if (svd->ishyperbolic) PetscCall(PetscMalloc1(requested,&svd->sign));
518: }
519: /* allocate V */
520: if (!svd->V) PetscCall(SVDGetBV(svd,&svd->V,NULL));
521: if (!oldsize) {
522: if (!((PetscObject)svd->V)->type_name) PetscCall(BVSetType(svd->V,BVMAT));
523: PetscCall(MatCreateVecsEmpty(svd->A,&tr,NULL));
524: PetscCall(BVSetSizesFromVec(svd->V,tr,requested));
525: PetscCall(VecDestroy(&tr));
526: } else PetscCall(BVResize(svd->V,requested,PETSC_FALSE));
527: /* allocate U */
528: if (svd->leftbasis && !svd->isgeneralized) {
529: if (!svd->U) PetscCall(SVDGetBV(svd,NULL,&svd->U));
530: if (!oldsize) {
531: if (!((PetscObject)svd->U)->type_name) PetscCall(BVSetType(svd->U,((PetscObject)svd->V)->type_name));
532: PetscCall(MatCreateVecsEmpty(svd->A,NULL,&tl));
533: PetscCall(BVSetSizesFromVec(svd->U,tl,requested));
534: PetscCall(VecDestroy(&tl));
535: } else PetscCall(BVResize(svd->U,requested,PETSC_FALSE));
536: } else if (svd->isgeneralized) { /* left basis for the GSVD */
537: if (!svd->U) PetscCall(SVDGetBV(svd,NULL,&svd->U));
538: if (!oldsize) {
539: if (!((PetscObject)svd->U)->type_name) PetscCall(BVSetType(svd->U,((PetscObject)svd->V)->type_name));
540: PetscCall(SVDCreateLeftTemplate(svd,&tl));
541: PetscCall(BVSetSizesFromVec(svd->U,tl,requested));
542: PetscCall(VecDestroy(&tl));
543: } else PetscCall(BVResize(svd->U,requested,PETSC_FALSE));
544: }
545: PetscFunctionReturn(PETSC_SUCCESS);
546: }