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: */
31: #undef __FUNCT__
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: PetscLogObjectMemory(ksp,size); /* HH - modified (by plane
55: rotations) hessenburg */
56: fgmres->hes_origin = fgmres->hh_origin + hh; /* HES - unmodified hessenburg */
57: fgmres->rs_origin = fgmres->hes_origin + hes; /* RS - the right-hand-side of the
58: Hessenberg system */
59: fgmres->cc_origin = fgmres->rs_origin + rs; /* CC - cosines for rotations */
60: fgmres->ss_origin = fgmres->cc_origin + cc; /* SS - sines for rotations */
62: if (ksp->calc_sings) {
63: /* Allocate workspace to hold Hessenberg matrix needed by Eispack */
64: size = (max_k + 3)*(max_k + 9)*sizeof(PetscScalar);
65: PetscMalloc(size,&fgmres->Rsvd);
66: PetscMalloc(5*(max_k+2)*sizeof(PetscReal),&fgmres->Dsvd);
67: PetscLogObjectMemory(ksp,size+5*(max_k+2)*sizeof(PetscReal));
68: }
70: /* Allocate array to hold pointers to user vectors. Note that we need
71: 4 + max_k + 1 (since we need it+1 vectors, and it <= max_k) */
72: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->vecs);
73: fgmres->vecs_allocated = VEC_OFFSET + 2 + max_k;
74: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->user_work);
75: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(int),&fgmres->mwork_alloc);
76: PetscLogObjectMemory(ksp,(VEC_OFFSET+2+max_k)*(2*sizeof(void *)+sizeof(int)));
78: /* New for FGMRES - Allocate array to hold pointers to preconditioned
79: vectors - same sizes as user vectors above */
80: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->prevecs);
81: PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&fgmres->prevecs_user_work);
82: PetscLogObjectMemory(ksp,(VEC_OFFSET+2+max_k)*(2*sizeof(void *)));
85: /* if q_preallocate = 0 then only allocate one "chunck" of space (for
86: 5 vectors) - additional will then be allocated from FGMREScycle()
87: as needed. Otherwise, allocate all of the space that could be needed */
88: if (fgmres->q_preallocate) {
89: fgmres->vv_allocated = VEC_OFFSET + 2 + max_k;
90: } else {
91: fgmres->vv_allocated = 5;
92: }
94: /* space for work vectors */
95: VecDuplicateVecs(VEC_RHS,fgmres->vv_allocated,&fgmres->user_work[0]);
96: PetscLogObjectParents(ksp,fgmres->vv_allocated,fgmres->user_work[0]);
97: for (k=0; k < fgmres->vv_allocated; k++) {
98: fgmres->vecs[k] = fgmres->user_work[0][k];
99: }
101: /* space for preconditioned vectors */
102: VecDuplicateVecs(VEC_RHS,fgmres->vv_allocated,&fgmres->prevecs_user_work[0]);
103: PetscLogObjectParents(ksp,fgmres->vv_allocated,fgmres->prevecs_user_work[0]);
104: for (k=0; k < fgmres->vv_allocated; k++) {
105: fgmres->prevecs[k] = fgmres->prevecs_user_work[0][k];
106: }
108: /* specify how many work vectors have been allocated in this
109: chunck" (the first one) */
110: fgmres->mwork_alloc[0] = fgmres->vv_allocated;
111: fgmres->nwork_alloc = 1;
113: return(0);
114: }
116: /*
117: FGMRESResidual - This routine computes the initial residual (NOT PRECONDITIONED)
118: */
119: #undef __FUNCT__
121: static int FGMRESResidual(KSP ksp)
122: {
123: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
124: PetscScalar mone = -1.0;
125: Mat Amat,Pmat;
126: MatStructure pflag;
127: int ierr;
130: PCGetOperators(ksp->B,&Amat,&Pmat,&pflag);
132: /* put A*x into VEC_TEMP */
133: MatMult(Amat,VEC_SOLN,VEC_TEMP);
134: /* now put residual (-A*x + f) into vec_vv(0) */
135: VecWAXPY(&mone,VEC_TEMP,VEC_RHS,VEC_VV(0));
136: return(0);
137: }
139: /*
141: FGMRESCycle - Run fgmres, possibly with restart. Return residual
142: history if requested.
144: input parameters:
145: . fgmres - structure containing parameters and work areas
147: output parameters:
148: . itcount - number of iterations used. If null, ignored.
149: . converged - 0 if not converged
151:
152: Notes:
153: On entry, the value in vector VEC_VV(0) should be
154: the initial residual.
157: */
158: #undef __FUNCT__
160: int FGMREScycle(int *itcount,KSP ksp)
161: {
163: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
164: PetscReal res_norm;
165: PetscReal hapbnd,tt;
166: PetscScalar zero = 0.0;
167: PetscScalar tmp;
168: PetscTruth hapend = PETSC_FALSE; /* indicates happy breakdown ending */
169: int ierr;
170: int loc_it; /* local count of # of dir. in Krylov space */
171: int max_k = fgmres->max_k; /* max # of directions Krylov space */
172: int max_it = ksp->max_it; /* max # of overall iterations for the method */
173: Mat Amat,Pmat;
174: MatStructure pflag;
178: /* Number of pseudo iterations since last restart is the number
179: of prestart directions */
180: loc_it = 0;
182: /* initial residual is in VEC_VV(0) - compute its norm*/
183: ierr = VecNorm(VEC_VV(0),NORM_2,&res_norm);
185: /* first entry in right-hand-side of hessenberg system is just
186: the initial residual norm */
187: *RS(0) = res_norm;
189: /* check for the convergence - maybe the current guess is good enough */
190: (*ksp->converged)(ksp,ksp->its,res_norm,&ksp->reason,ksp->cnvP);
191: if (ksp->reason) {
192: if (itcount) *itcount = 0;
193: return(0);
194: }
196: /* scale VEC_VV (the initial residual) */
197: tmp = 1.0/res_norm; VecScale(&tmp,VEC_VV(0));
199: /* FYI: AMS calls are for memory snooper */
200: PetscObjectTakeAccess(ksp);
201: ksp->rnorm = res_norm;
202: PetscObjectGrantAccess(ksp);
205: /* note: (fgmres->it) is always set one less than (loc_it) It is used in
206: KSPBUILDSolution_FGMRES, where it is passed to BuildFGmresSoln.
207: Note that when BuildFGmresSoln is called from this function,
208: (loc_it -1) is passed, so the two are equivalent */
209: fgmres->it = (loc_it - 1);
210:
211: /* MAIN ITERATION LOOP BEGINNING*/
212: /* keep iterating until we have converged OR generated the max number
213: of directions OR reached the max number of iterations for the method */
214: (*ksp->converged)(ksp,ksp->its,res_norm,&ksp->reason,ksp->cnvP);
215: while (!ksp->reason && loc_it < max_k && ksp->its < max_it) {
216: KSPLogResidualHistory(ksp,res_norm);
217: fgmres->it = (loc_it - 1);
218: KSPMonitor(ksp,ksp->its,res_norm);
220: /* see if more space is needed for work vectors */
221: if (fgmres->vv_allocated <= loc_it + VEC_OFFSET + 1) {
222: FGMRESGetNewVectors(ksp,loc_it+1);
223: /* (loc_it+1) is passed in as number of the first vector that should
224: be allocated */
225: }
227: /* CHANGE THE PRECONDITIONER? */
228: /* ModifyPC is the callback function that can be used to
229: change the PC or its attributes before its applied */
230: (*fgmres->modifypc)(ksp,ksp->its,loc_it,res_norm,fgmres->modifyctx);
231:
232:
233: /* apply PRECONDITIONER to direction vector and store with
234: preconditioned vectors in prevec */
235: PCApply(ksp->B,VEC_VV(loc_it),PREVEC(loc_it));
236:
237: PCGetOperators(ksp->B,&Amat,&Pmat,&pflag);
238: /* Multiply preconditioned vector by operator - put in VEC_VV(loc_it+1) */
239: MatMult(Amat,PREVEC(loc_it),VEC_VV(1+loc_it));
241:
242: /* update hessenberg matrix and do Gram-Schmidt - new direction is in
243: VEC_VV(1+loc_it)*/
244: (*fgmres->orthog)(ksp,loc_it);
246: /* new entry in hessenburg is the 2-norm of our new direction */
247: VecNorm(VEC_VV(loc_it+1),NORM_2,&tt);
248: *HH(loc_it+1,loc_it) = tt;
249: *HES(loc_it+1,loc_it) = tt;
251: /* Happy Breakdown Check */
252: hapbnd = PetscAbsScalar((tt) / *RS(loc_it));
253: /* RS(loc_it) contains the res_norm from the last iteration */
254: hapbnd = PetscMin(fgmres->haptol,hapbnd);
255: if (tt > hapbnd) {
256: tmp = 1.0/tt;
257: /* scale new direction by its norm */
258: VecScale(&tmp,VEC_VV(loc_it+1));
259: } else {
260: /* This happens when the solution is exactly reached. */
261: /* So there is no new direction... */
262: ierr = VecSet(&zero,VEC_TEMP); /* set VEC_TEMP to 0 */
263: hapend = PETSC_TRUE;
264: }
265: /* note that for FGMRES we could get HES(loc_it+1, loc_it) = 0 and the
266: current solution would not be exact if HES was singular. Note that
267: HH non-singular implies that HES is no singular, and HES is guaranteed
268: to be nonsingular when PREVECS are linearly independent and A is
269: nonsingular (in GMRES, the nonsingularity of A implies the nonsingularity
270: of HES). So we should really add a check to verify that HES is nonsingular.*/
272:
273: /* Now apply rotations to new col of hessenberg (and right side of system),
274: calculate new rotation, and get new residual norm at the same time*/
275: FGMRESUpdateHessenberg(ksp,loc_it,hapend,&res_norm);
276: loc_it++;
277: fgmres->it = (loc_it-1); /* Add this here in case it has converged */
278:
279: PetscObjectTakeAccess(ksp);
280: ksp->its++;
281: ksp->rnorm = res_norm;
282: PetscObjectGrantAccess(ksp);
284: (*ksp->converged)(ksp,ksp->its,res_norm,&ksp->reason,ksp->cnvP);
286: /* Catch error in happy breakdown and signal convergence and break from loop */
287: if (hapend) {
288: if (!ksp->reason) {
289: SETERRQ(0,"You reached the happy break down,but convergence was not indicated.");
290: }
291: break;
292: }
293: }
294: /* END OF ITERATION LOOP */
296: KSPLogResidualHistory(ksp,res_norm);
298: /*
299: Monitor if we know that we will not return for a restart */
300: if (ksp->reason || ksp->its >= max_it) {
301: KSPMonitor(ksp,ksp->its,res_norm);
302: }
304: if (itcount) *itcount = loc_it;
306: /*
307: Down here we have to solve for the "best" coefficients of the Krylov
308: columns, add the solution values together, and possibly unwind the
309: preconditioning from the solution
310: */
311:
312: /* Form the solution (or the solution so far) */
313: /* Note: must pass in (loc_it-1) for iteration count so that BuildFgmresSoln
314: properly navigates */
316: BuildFgmresSoln(RS(0),VEC_SOLN,VEC_SOLN,ksp,loc_it-1);
318: return(0);
319: }
321: /*
322: KSPSolve_FGMRES - This routine applies the FGMRES method.
325: Input Parameter:
326: . ksp - the Krylov space object that was set to use fgmres
328: Output Parameter:
329: . outits - number of iterations used
331: */
332: #undef __FUNCT__
335: int KSPSolve_FGMRES(KSP ksp,int *outits)
336: {
337: int ierr;
338: int cycle_its; /* iterations done in a call to FGMREScycle */
339: int itcount; /* running total of iterations, incl. those in restarts */
340: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
341: PetscTruth diagonalscale;
344: ierr = PCDiagonalScale(ksp->B,&diagonalscale);
345: if (diagonalscale) SETERRQ1(1,"Krylov method %s does not support diagonal scaling",ksp->type_name);
347: PetscObjectTakeAccess(ksp);
348: ksp->its = 0;
349: PetscObjectGrantAccess(ksp);
351: /* initialize */
352: itcount = 0;
354: /* Compute the initial (NOT preconditioned) residual */
355: if (!ksp->guess_zero) {
356: FGMRESResidual(ksp);
357: } else { /* guess is 0 so residual is F (which is in VEC_RHS) */
358: VecCopy(VEC_RHS,VEC_VV(0));
359: }
360: /* now the residual is in VEC_VV(0) - which is what
361: FGMREScycle expects... */
362:
363: ierr = FGMREScycle(&cycle_its,ksp);
364: itcount += cycle_its;
365: while (!ksp->reason) {
366: ierr = FGMRESResidual(ksp);
367: if (itcount >= ksp->max_it) break;
368: ierr = FGMREScycle(&cycle_its,ksp);
369: itcount += cycle_its;
370: }
371: /* mark lack of convergence */
372: if (itcount >= ksp->max_it) ksp->reason = KSP_DIVERGED_ITS;
374: *outits = itcount;
375: return(0);
376: }
378: /*
380: KSPDestroy_FGMRES - Frees all memory space used by the Krylov method.
382: */
383: #undef __FUNCT__
385: int KSPDestroy_FGMRES(KSP ksp)
386: {
387: KSP_FGMRES *fgmres = (KSP_FGMRES*)ksp->data;
388: int i,ierr;
391: /* Free the Hessenberg matrices */
392: if (fgmres->hh_origin) {PetscFree(fgmres->hh_origin);}
394: /* Free pointers to user variables */
395: if (fgmres->vecs) {PetscFree(fgmres->vecs);}
396: if (fgmres->prevecs) {PetscFree (fgmres->prevecs);}
398: /* free work vectors */
399: for (i=0; i < fgmres->nwork_alloc; i++) {
400: VecDestroyVecs(fgmres->user_work[i],fgmres->mwork_alloc[i]);
401: }
402: if (fgmres->user_work) {PetscFree(fgmres->user_work);}
404: for (i=0; i < fgmres->nwork_alloc; i++) {
405: VecDestroyVecs(fgmres->prevecs_user_work[i],fgmres->mwork_alloc[i]);
406: }
407: if (fgmres->prevecs_user_work) {PetscFree(fgmres->prevecs_user_work);}
409: if (fgmres->mwork_alloc) {PetscFree(fgmres->mwork_alloc);}
410: if (fgmres->nrs) {PetscFree(fgmres->nrs);}
411: if (fgmres->sol_temp) {VecDestroy(fgmres->sol_temp);}
412: if (fgmres->Rsvd) {PetscFree(fgmres->Rsvd);}
413: if (fgmres->Dsvd) {PetscFree(fgmres->Dsvd);}
414: if (fgmres->modifydestroy) {
415: (*fgmres->modifydestroy)(fgmres->modifyctx);
416: }
417: PetscFree(fgmres);
418: return(0);
419: }
421: /*
422: BuildFgmresSoln - create the solution from the starting vector and the
423: current iterates.
425: Input parameters:
426: nrs - work area of size it + 1.
427: vguess - index of initial guess
428: vdest - index of result. Note that vguess may == vdest (replace
429: guess with the solution).
430: it - HH upper triangular part is a block of size (it+1) x (it+1)
432: This is an internal routine that knows about the FGMRES internals.
433: */
434: #undef __FUNCT__
436: static int BuildFgmresSoln(PetscScalar* nrs,Vec vguess,Vec vdest,KSP ksp,int it)
437: {
438: PetscScalar tt,zero = 0.0,one = 1.0;
439: int ierr,ii,k,j;
440: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
443: /* Solve for solution vector that minimizes the residual */
445: /* If it is < 0, no fgmres steps have been performed */
446: if (it < 0) {
447: if (vdest != vguess) {
448: VecCopy(vguess,vdest);
449: }
450: return(0);
451: }
453: /* so fgmres steps HAVE been performed */
455: /* solve the upper triangular system - RS is the right side and HH is
456: the upper triangular matrix - put soln in nrs */
457: nrs[it] = *RS(it) / *HH(it,it);
458: for (ii=1; ii<=it; ii++) {
459: k = it - ii;
460: tt = *RS(k);
461: for (j=k+1; j<=it; j++) tt = tt - *HH(k,j) * nrs[j];
462: nrs[k] = tt / *HH(k,k);
463: }
465: /* Accumulate the correction to the soln of the preconditioned prob. in
466: VEC_TEMP - note that we use the preconditioned vectors */
467: VecSet(&zero,VEC_TEMP); /* set VEC_TEMP components to 0 */
468: VecMAXPY(it+1,nrs,VEC_TEMP,&PREVEC(0));
470: /* put updated solution into vdest.*/
471: if (vdest != vguess) {
472: VecCopy(VEC_TEMP,vdest);
473: VecAXPY(&one,vguess,vdest);
474: } else {/* replace guess with solution */
475: VecAXPY(&one,VEC_TEMP,vdest);
476: }
477: return(0);
478: }
480: /*
482: FGMRESUpdateHessenberg - Do the scalar work for the orthogonalization.
483: Return new residual.
485: input parameters:
487: . ksp - Krylov space object
488: . it - plane rotations are applied to the (it+1)th column of the
489: modified hessenberg (i.e. HH(:,it))
490: . hapend - PETSC_FALSE not happy breakdown ending.
492: output parameters:
493: . res - the new residual
494:
495: */
496: #undef __FUNCT__
498: static int FGMRESUpdateHessenberg(KSP ksp,int it,PetscTruth hapend,PetscReal *res)
499: {
500: PetscScalar *hh,*cc,*ss,tt;
501: int j;
502: KSP_FGMRES *fgmres = (KSP_FGMRES *)(ksp->data);
505: hh = HH(0,it); /* pointer to beginning of column to update - so
506: incrementing hh "steps down" the (it+1)th col of HH*/
507: cc = CC(0); /* beginning of cosine rotations */
508: ss = SS(0); /* beginning of sine rotations */
510: /* Apply all the previously computed plane rotations to the new column
511: of the Hessenberg matrix */
512: /* Note: this uses the rotation [conj(c) s ; -s c], c= cos(theta), s= sin(theta),
513: and some refs have [c s ; -conj(s) c] (don't be confused!) */
515: for (j=1; j<=it; j++) {
516: tt = *hh;
517: #if defined(PETSC_USE_COMPLEX)
518: *hh = PetscConj(*cc) * tt + *ss * *(hh+1);
519: #else
520: *hh = *cc * tt + *ss * *(hh+1);
521: #endif
522: hh++;
523: *hh = *cc++ * *hh - (*ss++ * tt);
524: /* hh, cc, and ss have all been incremented one by end of loop */
525: }
527: /*
528: compute the new plane rotation, and apply it to:
529: 1) the right-hand-side of the Hessenberg system (RS)
530: note: it affects RS(it) and RS(it+1)
531: 2) the new column of the Hessenberg matrix
532: note: it affects HH(it,it) which is currently pointed to
533: by hh and HH(it+1, it) (*(hh+1))
534: thus obtaining the updated value of the residual...
535: */
537: /* compute new plane rotation */
539: if (!hapend) {
540: #if defined(PETSC_USE_COMPLEX)
541: tt = PetscSqrtScalar(PetscConj(*hh) * *hh + PetscConj(*(hh+1)) * *(hh+1));
542: #else
543: tt = PetscSqrtScalar(*hh * *hh + *(hh+1) * *(hh+1));
544: #endif
545: if (tt == 0.0) {SETERRQ(PETSC_ERR_KSP_BRKDWN,"Your matrix or preconditioner is the null operator");}
546: *cc = *hh / tt; /* new cosine value */
547: *ss = *(hh+1) / tt; /* new sine value */
549: /* apply to 1) and 2) */
550: *RS(it+1) = - (*ss * *RS(it));
551: #if defined(PETSC_USE_COMPLEX)
552: *RS(it) = PetscConj(*cc) * *RS(it);
553: *hh = PetscConj(*cc) * *hh + *ss * *(hh+1);
554: #else
555: *RS(it) = *cc * *RS(it);
556: *hh = *cc * *hh + *ss * *(hh+1);
557: #endif
559: /* residual is the last element (it+1) of right-hand side! */
560: *res = PetscAbsScalar(*RS(it+1));
562: } else { /* happy breakdown: HH(it+1, it) = 0, therfore we don't need to apply
563: another rotation matrix (so RH doesn't change). The new residual is
564: always the new sine term times the residual from last time (RS(it)),
565: but now the new sine rotation would be zero...so the residual should
566: be zero...so we will multiply "zero" by the last residual. This might
567: not be exactly what we want to do here -could just return "zero". */
568:
569: *res = 0.0;
570: }
571: return(0);
572: }
574: /*
576: FGMRESGetNewVectors - This routine allocates more work vectors, starting from
577: VEC_VV(it), and more preconditioned work vectors, starting
578: from PREVEC(i).
580: */
581: #undef __FUNCT__
583: static int FGMRESGetNewVectors(KSP ksp,int it)
584: {
585: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
586: int nwork = fgmres->nwork_alloc; /* number of work vector chunks allocated */
587: int nalloc; /* number to allocate */
588: int k,ierr;
589:
591: nalloc = fgmres->delta_allocate; /* number of vectors to allocate
592: in a single chunk */
594: /* Adjust the number to allocate to make sure that we don't exceed the
595: number of available slots (fgmres->vecs_allocated)*/
596: if (it + VEC_OFFSET + nalloc >= fgmres->vecs_allocated){
597: nalloc = fgmres->vecs_allocated - it - VEC_OFFSET;
598: }
599: if (!nalloc) return(0);
601: fgmres->vv_allocated += nalloc; /* vv_allocated is the number of vectors allocated */
603: /* work vectors */
604: VecDuplicateVecs(VEC_RHS,nalloc,&fgmres->user_work[nwork]);
605: PetscLogObjectParents(ksp,nalloc,fgmres->user_work[nwork]);
606: for (k=0; k < nalloc; k++) {
607: fgmres->vecs[it+VEC_OFFSET+k] = fgmres->user_work[nwork][k];
608: }
609: /* specify size of chunk allocated */
610: fgmres->mwork_alloc[nwork] = nalloc;
612: /* preconditioned vectors */
613: VecDuplicateVecs(VEC_RHS,nalloc,&fgmres->prevecs_user_work[nwork]);
614: PetscLogObjectParents(ksp,nalloc,fgmres->prevecs_user_work[nwork]);
615: for (k=0; k < nalloc; k++) {
616: fgmres->prevecs[it+VEC_OFFSET+k] = fgmres->prevecs_user_work[nwork][k];
617: }
619: /* increment the number of work vector chunks */
620: fgmres->nwork_alloc++;
621: return(0);
622: }
624: /*
626: KSPBuildSolution_FGMRES
628: Input Parameter:
629: . ksp - the Krylov space object
630: . ptr-
632: Output Parameter:
633: . result - the solution
635: Note: this calls BuildFgmresSoln - the same function that FGMREScycle
636: calls directly.
638: */
639: #undef __FUNCT__
641: int KSPBuildSolution_FGMRES(KSP ksp,Vec ptr,Vec *result)
642: {
643: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
644: int ierr;
647: if (!ptr) {
648: if (!fgmres->sol_temp) {
649: VecDuplicate(ksp->vec_sol,&fgmres->sol_temp);
650: PetscLogObjectParent(ksp,fgmres->sol_temp);
651: }
652: ptr = fgmres->sol_temp;
653: }
654: if (!fgmres->nrs) {
655: /* allocate the work area */
656: PetscMalloc(fgmres->max_k*sizeof(PetscScalar),&fgmres->nrs);
657: PetscLogObjectMemory(ksp,fgmres->max_k*sizeof(PetscScalar));
658: }
659:
660: BuildFgmresSoln(fgmres->nrs,VEC_SOLN,ptr,ksp,fgmres->it);
661: *result = ptr;
662:
663: return(0);
664: }
666: /*
668: KSPView_FGMRES -Prints information about the current Krylov method
669: being used.
671: */
672: #undef __FUNCT__
674: int KSPView_FGMRES(KSP ksp,PetscViewer viewer)
675: {
676: KSP_FGMRES *fgmres = (KSP_FGMRES *)ksp->data;
677: char *cstr;
678: int ierr;
679: PetscTruth isascii;
682: PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&isascii);
683: if (isascii) {
684: if (fgmres->orthog == KSPGMRESUnmodifiedGramSchmidtOrthogonalization) {
685: cstr = "Unmodified Gram-Schmidt Orthogonalization";
686: } else if (fgmres->orthog == KSPGMRESModifiedGramSchmidtOrthogonalization) {
687: cstr = "Modified Gram-Schmidt Orthogonalization";
688: } else if (fgmres->orthog == KSPGMRESIROrthogonalization) {
689: cstr = "Unmodified Gram-Schmidt + 1 step Iterative Refinement Orthogonalization";
690: } else {
691: cstr = "unknown orthogonalization";
692: }
693: PetscViewerASCIIPrintf(viewer," FGMRES: restart=%d, using %sn",fgmres->max_k,cstr);
694: } else {
695: SETERRQ(1,"Viewer type not supported for this object");
696: }
697: return(0);
698: }
700: #undef __FUNCT__
702: int KSPSetFromOptions_FGMRES(KSP ksp)
703: {
704: int ierr,restart;
705: PetscReal haptol;
706: KSP_FGMRES *gmres = (KSP_FGMRES*)ksp->data;
707: PetscTruth flg;
710: PetscOptionsHead("KSP flexible GMRES Options");
711: PetscOptionsInt("-ksp_gmres_restart","Number of Krylov search directions","KSPGMRESSetRestart",gmres->max_k,&restart,&flg);
712: if (flg) { KSPGMRESSetRestart(ksp,restart); }
713: PetscOptionsReal("-ksp_gmres_haptol","Tolerance for declaring exact convergence (happy ending)","KSPGMRESSetHapTol",gmres->haptol,&haptol,&flg);
714: if (flg) { KSPGMRESSetHapTol(ksp,haptol); }
715: PetscOptionsName("-ksp_gmres_preallocate","Preallocate all Krylov vectors","KSPGMRESSetPreAllocateVectors",&flg);
716: if (flg) {KSPGMRESSetPreAllocateVectors(ksp);}
717: PetscOptionsLogicalGroupBegin("-ksp_gmres_unmodifiedgramschmidt","Use classical (unmodified) Gram-Schmidt (fast)","KSPGMRESSetOrthogonalization",&flg);
718: if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESUnmodifiedGramSchmidtOrthogonalization);}
719: PetscOptionsLogicalGroup("-ksp_gmres_modifiedgramschmidt","Use modified Gram-Schmidt (slow but more stable)","KSPGMRESSetOrthogonalization",&flg);
720: if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESModifiedGramSchmidtOrthogonalization);}
721: PetscOptionsLogicalGroupEnd("-ksp_gmres_irorthog","Use classical Gram-Schmidt with iterative refinement","KSPGMRESSetOrthogonalization",&flg);
722: if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESIROrthogonalization);}
723: PetscOptionsName("-ksp_gmres_krylov_monitor","Graphically plot the Krylov directions","KSPSetMonitor",&flg);
724: if (flg) {
725: PetscViewers viewers;
726: PetscViewersCreate(ksp->comm,&viewers);
727: KSPSetMonitor(ksp,KSPGMRESKrylovMonitor,viewers,(int (*)(void*))PetscViewersDestroy);
728: }
729: PetscOptionsLogicalGroupBegin("-ksp_fgmres_modifypcnochange","do not vary the preconditioner","KSPFGMRESSetModifyPC",&flg);
730: if (flg) {KSPFGMRESSetModifyPC(ksp,KSPFGMRESModifyPCNoChange,0,0);}
731: PetscOptionsLogicalGroupEnd("-ksp_fgmres_modifypcsles","vary the SLES based preconditioner","KSPFGMRESSetModifyPC",&flg);
732: if (flg) {KSPFGMRESSetModifyPC(ksp,KSPFGMRESModifyPCSLES,0,0);}
733: PetscOptionsTail();
734: return(0);
735: }
737: EXTERN_C_BEGIN
738: #undef __FUNCT__
740: int KSPFGMRESSetModifyPC_FGMRES(KSP ksp,int (*fcn)(KSP,int,int,PetscReal,void*),void *ctx,int (*d)(void*))
741: {
744: ((KSP_FGMRES *)ksp->data)->modifypc = fcn;
745: ((KSP_FGMRES *)ksp->data)->modifydestroy = d;
746: ((KSP_FGMRES *)ksp->data)->modifyctx = ctx;
747: return(0);
748: }
749: EXTERN_C_END
751: EXTERN_C_BEGIN
752: EXTERN int KSPGMRESSetPreAllocateVectors_GMRES(KSP);
753: EXTERN int KSPGMRESSetRestart_GMRES(KSP,int);
754: EXTERN int KSPGMRESSetOrthogonalization_GMRES(KSP,int (*)(KSP,int));
755: EXTERN_C_END
757: EXTERN_C_BEGIN
758: #undef __FUNCT__
760: int KSPCreate_FGMRES(KSP ksp)
761: {
762: KSP_FGMRES *fgmres;
763: int ierr;
766: PetscNew(KSP_FGMRES,&fgmres);
767: PetscMemzero(fgmres,sizeof(KSP_FGMRES));
768: PetscLogObjectMemory(ksp,sizeof(KSP_FGMRES));
769: ksp->data = (void*)fgmres;
770: ksp->ops->buildsolution = KSPBuildSolution_FGMRES;
772: ksp->ops->setup = KSPSetUp_FGMRES;
773: ksp->ops->solve = KSPSolve_FGMRES;
774: ksp->ops->destroy = KSPDestroy_FGMRES;
775: ksp->ops->view = KSPView_FGMRES;
776: ksp->ops->setfromoptions = KSPSetFromOptions_FGMRES;
777: ksp->ops->computeextremesingularvalues = 0;
778: ksp->ops->computeeigenvalues = 0;
780: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetPreAllocateVectors_C",
781: "KSPGMRESSetPreAllocateVectors_GMRES",
782: KSPGMRESSetPreAllocateVectors_GMRES);
783: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetOrthogonalization_C",
784: "KSPGMRESSetOrthogonalization_GMRES",
785: KSPGMRESSetOrthogonalization_GMRES);
786: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetRestart_C",
787: "KSPGMRESSetRestart_GMRES",
788: KSPGMRESSetRestart_GMRES);
789: PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPFGMRESSetModifyPC_C",
790: "KSPFGMRESSetModifyPC_FGMRES",
791: KSPFGMRESSetModifyPC_FGMRES);
794: fgmres->haptol = 1.0e-30;
795: fgmres->q_preallocate = 0;
796: fgmres->delta_allocate = FGMRES_DELTA_DIRECTIONS;
797: fgmres->orthog = KSPGMRESUnmodifiedGramSchmidtOrthogonalization;
798: fgmres->nrs = 0;
799: fgmres->sol_temp = 0;
800: fgmres->max_k = FGMRES_DEFAULT_MAXK;
801: fgmres->Rsvd = 0;
802: fgmres->modifypc = KSPFGMRESModifyPCNoChange;
803: fgmres->modifyctx = PETSC_NULL;
804: fgmres->modifydestroy = PETSC_NULL;
806: /*
807: This is not great since it changes this without explicit request from the user
808: but there is no left preconditioning in the FGMRES
809: */
810: PetscLogInfo(ksp,"Warning: Setting PC_SIDE for FGMRES to right!n");
811: ksp->pc_side = PC_RIGHT;
813: return(0);
814: }
815: EXTERN_C_END