Actual source code: fgmres.c
1: /* $Id: fgmres.c,v 1.29 2001/08/07 21:30:49 bsmith Exp $ */
3: /*
4: This file implements FGMRES (a Generalized Minimal Residual) method.
5: Reference: Saad, 1993.
7: Preconditioning: It the preconditioner is constant then this fgmres
8: code is equivalent to RIGHT-PRECONDITIONED GMRES.
10: Restarts: Restarts are basically solves with x0 not equal to zero.
11:
12: Contributed by Allison Baker
14: */
16: #include src/sles/ksp/impls/fgmres/fgmresp.h
17: #define FGMRES_DELTA_DIRECTIONS 10
18: #define FGMRES_DEFAULT_MAXK 30
19: static int FGMRESGetNewVectors(KSP,int);
20: static int FGMRESUpdateHessenberg(KSP,int,PetscTruth,PetscReal *);
21: static int BuildFgmresSoln(PetscScalar*,Vec,Vec,KSP,int);
23: /*
25: KSPSetUp_FGMRES - Sets up the workspace needed by fgmres.
27: This is called once, usually automatically by SLESSolve() or SLESSetUp(),
28: but can be called directly by KSPSetUp().
30: */
33: int KSPSetUp_FGMRES(KSP ksp)
34: {
35: unsigned int size,hh,hes,rs,cc;
36: int ierr,max_k,k;
37: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
40: if (ksp->pc_side == PC_SYMMETRIC) {
41: SETERRQ(2,"no symmetric preconditioning for KSPFGMRES");
42: } else if (ksp->pc_side == PC_LEFT) {
43: SETERRQ(2,"no left preconditioning for KSPFGMRES");
44: }
45: max_k = fgmres->max_k;
46: hh = (max_k + 2) * (max_k + 1);
47: hes = (max_k + 1) * (max_k + 1);
48: rs = (max_k + 2);
49: cc = (max_k + 1); /* SS and CC are the same size */
50: size = (hh + hes + rs + 2*cc) * sizeof(PetscScalar);
52: /* Allocate space and set pointers to beginning */
53: PetscMalloc(size,&fgmres->hh_origin);
54: PetscMemzero(fgmres->hh_origin,size);
55: PetscLogObjectMemory(ksp,size); /* HH - modified (by plane
56: rotations) hessenburg */
57: fgmres->hes_origin = fgmres->hh_origin + hh; /* HES - unmodified hessenburg */
58: fgmres->rs_origin = fgmres->hes_origin + hes; /* RS - the right-hand-side of the
59: Hessenberg system */
60: fgmres->cc_origin = fgmres->rs_origin + rs; /* CC - cosines for rotations */
61: fgmres->ss_origin = fgmres->cc_origin + cc; /* SS - sines for rotations */
63: if (ksp->calc_sings) {
64: /* Allocate workspace to hold Hessenberg matrix needed by Eispack */
65: size = (max_k + 3)*(max_k + 9)*sizeof(PetscScalar);
66: PetscMalloc(size,&fgmres->Rsvd);
67: PetscMalloc(5*(max_k+2)*sizeof(PetscReal),&fgmres->Dsvd);
68: PetscLogObjectMemory(ksp,size+5*(max_k+2)*sizeof(PetscReal));
69: }
71: /* Allocate array to hold pointers to user vectors. Note that we need
72: 4 + max_k + 1 (since we need it+1 vectors, and it <= max_k) */
73: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->vecs);
74: fgmres->vecs_allocated = VEC_OFFSET + 2 + max_k;
75: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->user_work);
76: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(int),&fgmres->mwork_alloc);
77: PetscLogObjectMemory(ksp,(VEC_OFFSET+2+max_k)*(2*sizeof(void *)+sizeof(int)));
79: /* New for FGMRES - Allocate array to hold pointers to preconditioned
80: vectors - same sizes as user vectors above */
81: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->prevecs);
82: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->prevecs_user_work);
83: PetscLogObjectMemory(ksp,(VEC_OFFSET+2+max_k)*(2*sizeof(void *)));
86: /* if q_preallocate = 0 then only allocate one "chunck" of space (for
87: 5 vectors) - additional will then be allocated from FGMREScycle()
88: as needed. Otherwise, allocate all of the space that could be needed */
89: if (fgmres->q_preallocate) {
90: fgmres->vv_allocated = VEC_OFFSET + 2 + max_k;
91: } else {
92: fgmres->vv_allocated = 5;
93: }
95: /* space for work vectors */
96: VecDuplicateVecs(VEC_RHS,fgmres->vv_allocated,&fgmres->user_work[0]);
97: PetscLogObjectParents(ksp,fgmres->vv_allocated,fgmres->user_work[0]);
98: for (k=0; k < fgmres->vv_allocated; k++) {
99: fgmres->vecs[k] = fgmres->user_work[0][k];
100: }
102: /* space for preconditioned vectors */
103: VecDuplicateVecs(VEC_RHS,fgmres->vv_allocated,&fgmres->prevecs_user_work[0]);
104: PetscLogObjectParents(ksp,fgmres->vv_allocated,fgmres->prevecs_user_work[0]);
105: for (k=0; k < fgmres->vv_allocated; k++) {
106: fgmres->prevecs[k] = fgmres->prevecs_user_work[0][k];
107: }
109: /* specify how many work vectors have been allocated in this
110: chunck" (the first one) */
111: fgmres->mwork_alloc[0] = fgmres->vv_allocated;
112: fgmres->nwork_alloc = 1;
114: return(0);
115: }
117: /*
118: FGMRESResidual - This routine computes the initial residual (NOT PRECONDITIONED)
119: */
122: static int FGMRESResidual(KSP ksp)
123: {
124: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
125: PetscScalar mone = -1.0;
126: Mat Amat,Pmat;
127: MatStructure pflag;
128: int ierr;
131: PCGetOperators(ksp->B,&Amat,&Pmat,&pflag);
133: /* put A*x into VEC_TEMP */
134: MatMult(Amat,VEC_SOLN,VEC_TEMP);
135: /* now put residual (-A*x + f) into vec_vv(0) */
136: VecWAXPY(&mone,VEC_TEMP,VEC_RHS,VEC_VV(0));
137: return(0);
138: }
140: /*
142: FGMRESCycle - Run fgmres, possibly with restart. Return residual
143: history if requested.
145: input parameters:
146: . fgmres - structure containing parameters and work areas
148: output parameters:
149: . itcount - number of iterations used. If null, ignored.
150: . converged - 0 if not converged
152:
153: Notes:
154: On entry, the value in vector VEC_VV(0) should be
155: the initial residual.
158: */
161: int FGMREScycle(int *itcount,KSP ksp)
162: {
164: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
165: PetscReal res_norm;
166: PetscReal hapbnd,tt;
167: PetscScalar zero = 0.0;
168: PetscScalar tmp;
169: PetscTruth hapend = PETSC_FALSE; /* indicates happy breakdown ending */
170: int ierr;
171: int loc_it; /* local count of # of dir. in Krylov space */
172: int max_k = fgmres->max_k; /* max # of directions Krylov space */
173: int max_it = ksp->max_it; /* max # of overall iterations for the method */
174: Mat Amat,Pmat;
175: MatStructure pflag;
179: /* Number of pseudo iterations since last restart is the number
180: of prestart directions */
181: loc_it = 0;
183: /* initial residual is in VEC_VV(0) - compute its norm*/
184: VecNorm(VEC_VV(0),NORM_2,&res_norm);
186: /* first entry in right-hand-side of hessenberg system is just
187: the initial residual norm */
188: *RS(0) = res_norm;
190: /* check for the convergence - maybe the current guess is good enough */
191: (*ksp->converged)(ksp,ksp->its,res_norm,&ksp->reason,ksp->cnvP);
192: if (ksp->reason) {
193: if (itcount) *itcount = 0;
194: return(0);
195: }
197: /* scale VEC_VV (the initial residual) */
198: tmp = 1.0/res_norm; VecScale(&tmp,VEC_VV(0));
200: /* FYI: AMS calls are for memory snooper */
201: PetscObjectTakeAccess(ksp);
202: ksp->rnorm = res_norm;
203: PetscObjectGrantAccess(ksp);
206: /* note: (fgmres->it) is always set one less than (loc_it) It is used in
207: KSPBUILDSolution_FGMRES, where it is passed to BuildFGmresSoln.
208: Note that when BuildFGmresSoln is called from this function,
209: (loc_it -1) is passed, so the two are equivalent */
210: fgmres->it = (loc_it - 1);
211:
212: /* MAIN ITERATION LOOP BEGINNING*/
213: /* keep iterating until we have converged OR generated the max number
214: of directions OR reached the max number of iterations for the method */
215: (*ksp->converged)(ksp,ksp->its,res_norm,&ksp->reason,ksp->cnvP);
216: while (!ksp->reason && loc_it < max_k && ksp->its < max_it) {
217: KSPLogResidualHistory(ksp,res_norm);
218: fgmres->it = (loc_it - 1);
219: KSPMonitor(ksp,ksp->its,res_norm);
221: /* see if more space is needed for work vectors */
222: if (fgmres->vv_allocated <= loc_it + VEC_OFFSET + 1) {
223: FGMRESGetNewVectors(ksp,loc_it+1);
224: /* (loc_it+1) is passed in as number of the first vector that should
225: be allocated */
226: }
228: /* CHANGE THE PRECONDITIONER? */
229: /* ModifyPC is the callback function that can be used to
230: change the PC or its attributes before its applied */
231: (*fgmres->modifypc)(ksp,ksp->its,loc_it,res_norm,fgmres->modifyctx);
232:
233:
234: /* apply PRECONDITIONER to direction vector and store with
235: preconditioned vectors in prevec */
236: PCApply(ksp->B,VEC_VV(loc_it),PREVEC(loc_it),PC_RIGHT);
237:
238: PCGetOperators(ksp->B,&Amat,&Pmat,&pflag);
239: /* Multiply preconditioned vector by operator - put in VEC_VV(loc_it+1) */
240: MatMult(Amat,PREVEC(loc_it),VEC_VV(1+loc_it));
242:
243: /* update hessenberg matrix and do Gram-Schmidt - new direction is in
244: VEC_VV(1+loc_it)*/
245: (*fgmres->orthog)(ksp,loc_it);
247: /* new entry in hessenburg is the 2-norm of our new direction */
248: VecNorm(VEC_VV(loc_it+1),NORM_2,&tt);
249: *HH(loc_it+1,loc_it) = tt;
250: *HES(loc_it+1,loc_it) = tt;
252: /* Happy Breakdown Check */
253: hapbnd = PetscAbsScalar((tt) / *RS(loc_it));
254: /* RS(loc_it) contains the res_norm from the last iteration */
255: hapbnd = PetscMin(fgmres->haptol,hapbnd);
256: if (tt > hapbnd) {
257: tmp = 1.0/tt;
258: /* scale new direction by its norm */
259: VecScale(&tmp,VEC_VV(loc_it+1));
260: } else {
261: /* This happens when the solution is exactly reached. */
262: /* So there is no new direction... */
263: VecSet(&zero,VEC_TEMP); /* set VEC_TEMP to 0 */
264: hapend = PETSC_TRUE;
265: }
266: /* note that for FGMRES we could get HES(loc_it+1, loc_it) = 0 and the
267: current solution would not be exact if HES was singular. Note that
268: HH non-singular implies that HES is no singular, and HES is guaranteed
269: to be nonsingular when PREVECS are linearly independent and A is
270: nonsingular (in GMRES, the nonsingularity of A implies the nonsingularity
271: of HES). So we should really add a check to verify that HES is nonsingular.*/
273:
274: /* Now apply rotations to new col of hessenberg (and right side of system),
275: calculate new rotation, and get new residual norm at the same time*/
276: FGMRESUpdateHessenberg(ksp,loc_it,hapend,&res_norm);
277: loc_it++;
278: fgmres->it = (loc_it-1); /* Add this here in case it has converged */
279:
280: PetscObjectTakeAccess(ksp);
281: ksp->its++;
282: ksp->rnorm = res_norm;
283: PetscObjectGrantAccess(ksp);
285: (*ksp->converged)(ksp,ksp->its,res_norm,&ksp->reason,ksp->cnvP);
287: /* Catch error in happy breakdown and signal convergence and break from loop */
288: if (hapend) {
289: if (!ksp->reason) {
290: SETERRQ(0,"You reached the happy break down,but convergence was not indicated.");
291: }
292: break;
293: }
294: }
295: /* END OF ITERATION LOOP */
297: KSPLogResidualHistory(ksp,res_norm);
299: /*
300: Monitor if we know that we will not return for a restart */
301: if (ksp->reason || ksp->its >= max_it) {
302: KSPMonitor(ksp,ksp->its,res_norm);
303: }
305: if (itcount) *itcount = loc_it;
307: /*
308: Down here we have to solve for the "best" coefficients of the Krylov
309: columns, add the solution values together, and possibly unwind the
310: preconditioning from the solution
311: */
312:
313: /* Form the solution (or the solution so far) */
314: /* Note: must pass in (loc_it-1) for iteration count so that BuildFgmresSoln
315: properly navigates */
317: BuildFgmresSoln(RS(0),VEC_SOLN,VEC_SOLN,ksp,loc_it-1);
319: return(0);
320: }
322: /*
323: KSPSolve_FGMRES - This routine applies the FGMRES method.
326: Input Parameter:
327: . ksp - the Krylov space object that was set to use fgmres
329: Output Parameter:
330: . outits - number of iterations used
332: */
336: int KSPSolve_FGMRES(KSP ksp,int *outits)
337: {
338: int ierr;
339: int cycle_its; /* iterations done in a call to FGMREScycle */
340: int itcount; /* running total of iterations, incl. those in restarts */
341: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
342: PetscTruth diagonalscale;
345: PCDiagonalScale(ksp->B,&diagonalscale);
346: if (diagonalscale) SETERRQ1(1,"Krylov method %s does not support diagonal scaling",ksp->type_name);
348: PetscObjectTakeAccess(ksp);
349: ksp->its = 0;
350: PetscObjectGrantAccess(ksp);
352: /* initialize */
353: itcount = 0;
355: /* Compute the initial (NOT preconditioned) residual */
356: if (!ksp->guess_zero) {
357: FGMRESResidual(ksp);
358: } else { /* guess is 0 so residual is F (which is in VEC_RHS) */
359: VecCopy(VEC_RHS,VEC_VV(0));
360: }
361: /* now the residual is in VEC_VV(0) - which is what
362: FGMREScycle expects... */
363:
364: FGMREScycle(&cycle_its,ksp);
365: itcount += cycle_its;
366: while (!ksp->reason) {
367: FGMRESResidual(ksp);
368: if (itcount >= ksp->max_it) break;
369: FGMREScycle(&cycle_its,ksp);
370: itcount += cycle_its;
371: }
372: /* mark lack of convergence */
373: if (itcount >= ksp->max_it) ksp->reason = KSP_DIVERGED_ITS;
375: *outits = itcount;
376: return(0);
377: }
379: /*
381: KSPDestroy_FGMRES - Frees all memory space used by the Krylov method.
383: */
386: int KSPDestroy_FGMRES(KSP ksp)
387: {
388: KSP_FGMRES *fgmres = (KSP_FGMRES*)ksp->data;
389: int i,ierr;
392: /* Free the Hessenberg matrices */
393: if (fgmres->hh_origin) {PetscFree(fgmres->hh_origin);}
395: /* Free pointers to user variables */
396: if (fgmres->vecs) {PetscFree(fgmres->vecs);}
397: if (fgmres->prevecs) {PetscFree (fgmres->prevecs);}
399: /* free work vectors */
400: for (i=0; i < fgmres->nwork_alloc; i++) {
401: VecDestroyVecs(fgmres->user_work[i],fgmres->mwork_alloc[i]);
402: }
403: if (fgmres->user_work) {PetscFree(fgmres->user_work);}
405: for (i=0; i < fgmres->nwork_alloc; i++) {
406: VecDestroyVecs(fgmres->prevecs_user_work[i],fgmres->mwork_alloc[i]);
407: }
408: if (fgmres->prevecs_user_work) {PetscFree(fgmres->prevecs_user_work);}
410: if (fgmres->mwork_alloc) {PetscFree(fgmres->mwork_alloc);}
411: if (fgmres->nrs) {PetscFree(fgmres->nrs);}
412: if (fgmres->sol_temp) {VecDestroy(fgmres->sol_temp);}
413: if (fgmres->Rsvd) {PetscFree(fgmres->Rsvd);}
414: if (fgmres->Dsvd) {PetscFree(fgmres->Dsvd);}
415: if (fgmres->modifydestroy) {
416: (*fgmres->modifydestroy)(fgmres->modifyctx);
417: }
418: PetscFree(fgmres);
419: return(0);
420: }
422: /*
423: BuildFgmresSoln - create the solution from the starting vector and the
424: current iterates.
426: Input parameters:
427: nrs - work area of size it + 1.
428: vguess - index of initial guess
429: vdest - index of result. Note that vguess may == vdest (replace
430: guess with the solution).
431: it - HH upper triangular part is a block of size (it+1) x (it+1)
433: This is an internal routine that knows about the FGMRES internals.
434: */
437: static int BuildFgmresSoln(PetscScalar* nrs,Vec vguess,Vec vdest,KSP ksp,int it)
438: {
439: PetscScalar tt,zero = 0.0,one = 1.0;
440: int ierr,ii,k,j;
441: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
444: /* Solve for solution vector that minimizes the residual */
446: /* If it is < 0, no fgmres steps have been performed */
447: if (it < 0) {
448: if (vdest != vguess) {
449: VecCopy(vguess,vdest);
450: }
451: return(0);
452: }
454: /* so fgmres steps HAVE been performed */
456: /* solve the upper triangular system - RS is the right side and HH is
457: the upper triangular matrix - put soln in nrs */
458: nrs[it] = *RS(it) / *HH(it,it);
459: for (ii=1; ii<=it; ii++) {
460: k = it - ii;
461: tt = *RS(k);
462: for (j=k+1; j<=it; j++) tt = tt - *HH(k,j) * nrs[j];
463: nrs[k] = tt / *HH(k,k);
464: }
466: /* Accumulate the correction to the soln of the preconditioned prob. in
467: VEC_TEMP - note that we use the preconditioned vectors */
468: VecSet(&zero,VEC_TEMP); /* set VEC_TEMP components to 0 */
469: VecMAXPY(it+1,nrs,VEC_TEMP,&PREVEC(0));
471: /* put updated solution into vdest.*/
472: if (vdest != vguess) {
473: VecCopy(VEC_TEMP,vdest);
474: VecAXPY(&one,vguess,vdest);
475: } else {/* replace guess with solution */
476: VecAXPY(&one,VEC_TEMP,vdest);
477: }
478: return(0);
479: }
481: /*
483: FGMRESUpdateHessenberg - Do the scalar work for the orthogonalization.
484: Return new residual.
486: input parameters:
488: . ksp - Krylov space object
489: . it - plane rotations are applied to the (it+1)th column of the
490: modified hessenberg (i.e. HH(:,it))
491: . hapend - PETSC_FALSE not happy breakdown ending.
493: output parameters:
494: . res - the new residual
495:
496: */
499: static int FGMRESUpdateHessenberg(KSP ksp,int it,PetscTruth hapend,PetscReal *res)
500: {
501: PetscScalar *hh,*cc,*ss,tt;
502: int j;
503: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
506: hh = HH(0,it); /* pointer to beginning of column to update - so
507: incrementing hh "steps down" the (it+1)th col of HH*/
508: cc = CC(0); /* beginning of cosine rotations */
509: ss = SS(0); /* beginning of sine rotations */
511: /* Apply all the previously computed plane rotations to the new column
512: of the Hessenberg matrix */
513: /* Note: this uses the rotation [conj(c) s ; -s c], c= cos(theta), s= sin(theta),
514: and some refs have [c s ; -conj(s) c] (don't be confused!) */
516: for (j=1; j<=it; j++) {
517: tt = *hh;
518: #if defined(PETSC_USE_COMPLEX)
519: *hh = PetscConj(*cc) * tt + *ss * *(hh+1);
520: #else
521: *hh = *cc * tt + *ss * *(hh+1);
522: #endif
523: hh++;
524: *hh = *cc++ * *hh - (*ss++ * tt);
525: /* hh, cc, and ss have all been incremented one by end of loop */
526: }
528: /*
529: compute the new plane rotation, and apply it to:
530: 1) the right-hand-side of the Hessenberg system (RS)
531: note: it affects RS(it) and RS(it+1)
532: 2) the new column of the Hessenberg matrix
533: note: it affects HH(it,it) which is currently pointed to
534: by hh and HH(it+1, it) (*(hh+1))
535: thus obtaining the updated value of the residual...
536: */
538: /* compute new plane rotation */
540: if (!hapend) {
541: #if defined(PETSC_USE_COMPLEX)
542: tt = PetscSqrtScalar(PetscConj(*hh) * *hh + PetscConj(*(hh+1)) * *(hh+1));
543: #else
544: tt = PetscSqrtScalar(*hh * *hh + *(hh+1) * *(hh+1));
545: #endif
546: if (tt == 0.0) {SETERRQ(PETSC_ERR_KSP_BRKDWN,"Your matrix or preconditioner is the null operator");}
547: *cc = *hh / tt; /* new cosine value */
548: *ss = *(hh+1) / tt; /* new sine value */
550: /* apply to 1) and 2) */
551: *RS(it+1) = - (*ss * *RS(it));
552: #if defined(PETSC_USE_COMPLEX)
553: *RS(it) = PetscConj(*cc) * *RS(it);
554: *hh = PetscConj(*cc) * *hh + *ss * *(hh+1);
555: #else
556: *RS(it) = *cc * *RS(it);
557: *hh = *cc * *hh + *ss * *(hh+1);
558: #endif
560: /* residual is the last element (it+1) of right-hand side! */
561: *res = PetscAbsScalar(*RS(it+1));
563: } else { /* happy breakdown: HH(it+1, it) = 0, therfore we don't need to apply
564: another rotation matrix (so RH doesn't change). The new residual is
565: always the new sine term times the residual from last time (RS(it)),
566: but now the new sine rotation would be zero...so the residual should
567: be zero...so we will multiply "zero" by the last residual. This might
568: not be exactly what we want to do here -could just return "zero". */
569:
570: *res = 0.0;
571: }
572: return(0);
573: }
575: /*
577: FGMRESGetNewVectors - This routine allocates more work vectors, starting from
578: VEC_VV(it), and more preconditioned work vectors, starting
579: from PREVEC(i).
581: */
584: static int FGMRESGetNewVectors(KSP ksp,int it)
585: {
586: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
587: int nwork = fgmres->nwork_alloc; /* number of work vector chunks allocated */
588: int nalloc; /* number to allocate */
589: int k,ierr;
590:
592: nalloc = fgmres->delta_allocate; /* number of vectors to allocate
593: in a single chunk */
595: /* Adjust the number to allocate to make sure that we don't exceed the
596: number of available slots (fgmres->vecs_allocated)*/
597: if (it + VEC_OFFSET + nalloc >= fgmres->vecs_allocated){
598: nalloc = fgmres->vecs_allocated - it - VEC_OFFSET;
599: }
600: if (!nalloc) return(0);
602: fgmres->vv_allocated += nalloc; /* vv_allocated is the number of vectors allocated */
604: /* work vectors */
605: VecDuplicateVecs(VEC_RHS,nalloc,&fgmres->user_work[nwork]);
606: PetscLogObjectParents(ksp,nalloc,fgmres->user_work[nwork]);
607: for (k=0; k < nalloc; k++) {
608: fgmres->vecs[it+VEC_OFFSET+k] = fgmres->user_work[nwork][k];
609: }
610: /* specify size of chunk allocated */
611: fgmres->mwork_alloc[nwork] = nalloc;
613: /* preconditioned vectors */
614: VecDuplicateVecs(VEC_RHS,nalloc,&fgmres->prevecs_user_work[nwork]);
615: PetscLogObjectParents(ksp,nalloc,fgmres->prevecs_user_work[nwork]);
616: for (k=0; k < nalloc; k++) {
617: fgmres->prevecs[it+VEC_OFFSET+k] = fgmres->prevecs_user_work[nwork][k];
618: }
620: /* increment the number of work vector chunks */
621: fgmres->nwork_alloc++;
622: return(0);
623: }
625: /*
627: KSPBuildSolution_FGMRES
629: Input Parameter:
630: . ksp - the Krylov space object
631: . ptr-
633: Output Parameter:
634: . result - the solution
636: Note: this calls BuildFgmresSoln - the same function that FGMREScycle
637: calls directly.
639: */
642: int KSPBuildSolution_FGMRES(KSP ksp,Vec ptr,Vec *result)
643: {
644: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
645: int ierr;
648: if (!ptr) {
649: if (!fgmres->sol_temp) {
650: VecDuplicate(ksp->vec_sol,&fgmres->sol_temp);
651: PetscLogObjectParent(ksp,fgmres->sol_temp);
652: }
653: ptr = fgmres->sol_temp;
654: }
655: if (!fgmres->nrs) {
656: /* allocate the work area */
657: PetscMalloc(fgmres->max_k*sizeof(PetscScalar),&fgmres->nrs);
658: PetscLogObjectMemory(ksp,fgmres->max_k*sizeof(PetscScalar));
659: }
660:
661: BuildFgmresSoln(fgmres->nrs,VEC_SOLN,ptr,ksp,fgmres->it);
662: *result = ptr;
663:
664: return(0);
665: }
667: /*
669: KSPView_FGMRES -Prints information about the current Krylov method
670: being used.
672: */
675: int KSPView_FGMRES(KSP ksp,PetscViewer viewer)
676: {
677: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
678: char *cstr;
679: int ierr;
680: PetscTruth isascii;
683: PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&isascii);
684: if (isascii) {
685: if (fgmres->orthog == KSPGMRESUnmodifiedGramSchmidtOrthogonalization) {
686: cstr = "Unmodified Gram-Schmidt Orthogonalization";
687: } else if (fgmres->orthog == KSPGMRESModifiedGramSchmidtOrthogonalization) {
688: cstr = "Modified Gram-Schmidt Orthogonalization";
689: } else if (fgmres->orthog == KSPGMRESIROrthogonalization) {
690: cstr = "Unmodified Gram-Schmidt + 1 step Iterative Refinement Orthogonalization";
691: } else {
692: cstr = "unknown orthogonalization";
693: }
694: PetscViewerASCIIPrintf(viewer," FGMRES: restart=%d, using %s\n",fgmres->max_k,cstr);
695: } else {
696: SETERRQ(1,"Viewer type not supported for this object");
697: }
698: return(0);
699: }
703: int KSPSetFromOptions_FGMRES(KSP ksp)
704: {
705: int ierr,restart;
706: PetscReal haptol;
707: KSP_FGMRES *gmres = (KSP_FGMRES*)ksp->data;
708: PetscTruth flg;
711: PetscOptionsHead("KSP flexible GMRES Options");
712: PetscOptionsInt("-ksp_gmres_restart","Number of Krylov search directions","KSPGMRESSetRestart",gmres->max_k,&restart,&flg);
713: if (flg) { KSPGMRESSetRestart(ksp,restart); }
714: PetscOptionsReal("-ksp_gmres_haptol","Tolerance for declaring exact convergence (happy ending)","KSPGMRESSetHapTol",gmres->haptol,&haptol,&flg);
715: if (flg) { KSPGMRESSetHapTol(ksp,haptol); }
716: PetscOptionsName("-ksp_gmres_preallocate","Preallocate all Krylov vectors","KSPGMRESSetPreAllocateVectors",&flg);
717: if (flg) {KSPGMRESSetPreAllocateVectors(ksp);}
718: PetscOptionsLogicalGroupBegin("-ksp_gmres_unmodifiedgramschmidt","Use classical (unmodified) Gram-Schmidt (fast)","KSPGMRESSetOrthogonalization",&flg);
719: if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESUnmodifiedGramSchmidtOrthogonalization);}
720: PetscOptionsLogicalGroup("-ksp_gmres_modifiedgramschmidt","Use modified Gram-Schmidt (slow but more stable)","KSPGMRESSetOrthogonalization",&flg);
721: if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESModifiedGramSchmidtOrthogonalization);}
722: PetscOptionsLogicalGroupEnd("-ksp_gmres_irorthog","Use classical Gram-Schmidt with iterative refinement","KSPGMRESSetOrthogonalization",&flg);
723: if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESIROrthogonalization);}
724: PetscOptionsName("-ksp_gmres_krylov_monitor","Graphically plot the Krylov directions","KSPSetMonitor",&flg);
725: if (flg) {
726: PetscViewers viewers;
727: PetscViewersCreate(ksp->comm,&viewers);
728: KSPSetMonitor(ksp,KSPGMRESKrylovMonitor,viewers,(int (*)(void*))PetscViewersDestroy);
729: }
730: PetscOptionsLogicalGroupBegin("-ksp_fgmres_modifypcnochange","do not vary the preconditioner","KSPFGMRESSetModifyPC",&flg);
731: if (flg) {KSPFGMRESSetModifyPC(ksp,KSPFGMRESModifyPCNoChange,0,0);}
732: PetscOptionsLogicalGroupEnd("-ksp_fgmres_modifypcsles","vary the SLES based preconditioner","KSPFGMRESSetModifyPC",&flg);
733: if (flg) {KSPFGMRESSetModifyPC(ksp,KSPFGMRESModifyPCSLES,0,0);}
734: PetscOptionsTail();
735: return(0);
736: }
738: EXTERN int KSPComputeExtremeSingularValues_FGMRES(KSP,PetscReal *,PetscReal *);
739: EXTERN int KSPComputeEigenvalues_FGMRES(KSP,int,PetscReal *,PetscReal *,int *);
741: EXTERN_C_BEGIN
744: int KSPFGMRESSetModifyPC_FGMRES(KSP ksp,int (*fcn)(KSP,int,int,PetscReal,void*),void *ctx,int (*d)(void*))
745: {
748: ((KSP_FGMRES *)ksp->data)->modifypc = fcn;
749: ((KSP_FGMRES *)ksp->data)->modifydestroy = d;
750: ((KSP_FGMRES *)ksp->data)->modifyctx = ctx;
751: return(0);
752: }
753: EXTERN_C_END
755: EXTERN_C_BEGIN
756: EXTERN int KSPGMRESSetPreAllocateVectors_GMRES(KSP);
757: EXTERN int KSPGMRESSetRestart_GMRES(KSP,int);
758: EXTERN int KSPGMRESSetOrthogonalization_GMRES(KSP,int (*)(KSP,int));
759: EXTERN_C_END
763: int KSPDestroy_FGMRES_Internal(KSP ksp)
764: {
765: KSP_FGMRES *gmres = (KSP_FGMRES*)ksp->data;
766: int i,ierr;
769: /* Free the Hessenberg matrix */
770: if (gmres->hh_origin) {PetscFree(gmres->hh_origin);}
772: /* Free the pointer to user variables */
773: if (gmres->vecs) {PetscFree(gmres->vecs);}
775: /* free work vectors */
776: for (i=0; i<gmres->nwork_alloc; i++) {
777: VecDestroyVecs(gmres->user_work[i],gmres->mwork_alloc[i]);
778: }
779: if (gmres->user_work) {PetscFree(gmres->user_work);}
780: if (gmres->mwork_alloc) {PetscFree(gmres->mwork_alloc);}
781: if (gmres->nrs) {PetscFree(gmres->nrs);}
782: if (gmres->sol_temp) {VecDestroy(gmres->sol_temp);}
783: if (gmres->Rsvd) {PetscFree(gmres->Rsvd);}
784: if (gmres->Dsvd) {PetscFree(gmres->Dsvd);}
786: return(0);
787: }
789: EXTERN_C_BEGIN
792: int KSPGMRESSetRestart_FGMRES(KSP ksp,int max_k)
793: {
794: KSP_FGMRES *gmres = (KSP_FGMRES *)ksp->data;
795: int ierr;
798: if (max_k < 1) SETERRQ(1,"Restart must be positive");
799: if (!ksp->setupcalled) {
800: gmres->max_k = max_k;
801: } else if (gmres->max_k != max_k) {
802: gmres->max_k = max_k;
803: ksp->setupcalled = 0;
804: /* free the data structures, then create them again */
805: KSPDestroy_FGMRES_Internal(ksp);
806: }
807: return(0);
808: }
809: EXTERN_C_END
811: EXTERN_C_BEGIN
814: int KSPCreate_FGMRES(KSP ksp)
815: {
816: KSP_FGMRES *fgmres;
817: int ierr;
820: PetscNew(KSP_FGMRES,&fgmres);
821: PetscMemzero(fgmres,sizeof(KSP_FGMRES));
822: PetscLogObjectMemory(ksp,sizeof(KSP_FGMRES));
823: ksp->data = (void*)fgmres;
824: ksp->ops->buildsolution = KSPBuildSolution_FGMRES;
826: ksp->ops->setup = KSPSetUp_FGMRES;
827: ksp->ops->solve = KSPSolve_FGMRES;
828: ksp->ops->destroy = KSPDestroy_FGMRES;
829: ksp->ops->view = KSPView_FGMRES;
830: ksp->ops->setfromoptions = KSPSetFromOptions_FGMRES;
831: ksp->ops->computeextremesingularvalues = KSPComputeExtremeSingularValues_FGMRES;
832: ksp->ops->computeeigenvalues = KSPComputeEigenvalues_FGMRES;
834: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetPreAllocateVectors_C",
835: "KSPGMRESSetPreAllocateVectors_GMRES",
836: KSPGMRESSetPreAllocateVectors_GMRES);
837: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetOrthogonalization_C",
838: "KSPGMRESSetOrthogonalization_GMRES",
839: KSPGMRESSetOrthogonalization_GMRES);
840: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetRestart_C",
841: "KSPGMRESSetRestart_FGMRES",
842: KSPGMRESSetRestart_FGMRES);
843: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPFGMRESSetModifyPC_C",
844: "KSPFGMRESSetModifyPC_FGMRES",
845: KSPFGMRESSetModifyPC_FGMRES);
848: fgmres->haptol = 1.0e-30;
849: fgmres->q_preallocate = 0;
850: fgmres->delta_allocate = FGMRES_DELTA_DIRECTIONS;
851: fgmres->orthog = KSPGMRESUnmodifiedGramSchmidtOrthogonalization;
852: fgmres->nrs = 0;
853: fgmres->sol_temp = 0;
854: fgmres->max_k = FGMRES_DEFAULT_MAXK;
855: fgmres->Rsvd = 0;
856: fgmres->modifypc = KSPFGMRESModifyPCNoChange;
857: fgmres->modifyctx = PETSC_NULL;
858: fgmres->modifydestroy = PETSC_NULL;
860: /*
861: This is not great since it changes this without explicit request from the user
862: but there is no left preconditioning in the FGMRES
863: */
864: PetscLogInfo(ksp,"Warning: Setting PC_SIDE for FGMRES to right!\n");
865: ksp->pc_side = PC_RIGHT;
867: return(0);
868: }
869: EXTERN_C_END