2: #include <../src/ksp/ksp/impls/gmres/lgmres/lgmresimpl.h> 4: #define LGMRES_DELTA_DIRECTIONS 10 5: #define LGMRES_DEFAULT_MAXK 30 6: #define LGMRES_DEFAULT_AUGDIM 2 /*default number of augmentation vectors */ 7: static PetscErrorCode KSPLGMRESGetNewVectors(KSP,PetscInt);
8: static PetscErrorCode KSPLGMRESUpdateHessenberg(KSP,PetscInt,PetscBool,PetscReal*);
9: static PetscErrorCode KSPLGMRESBuildSoln(PetscScalar*,Vec,Vec,KSP,PetscInt);
11: PetscErrorCode KSPLGMRESSetAugDim(KSP ksp, PetscInt dim) 12: {
16: PetscTryMethod((ksp),"KSPLGMRESSetAugDim_C",(KSP,PetscInt),(ksp,dim));
17: return(0);
18: }
20: PetscErrorCode KSPLGMRESSetConstant(KSP ksp) 21: {
25: PetscTryMethod((ksp),"KSPLGMRESSetConstant_C",(KSP),(ksp));
26: return(0);
27: }
29: /*
30: KSPSetUp_LGMRES - Sets up the workspace needed by lgmres.
32: This is called once, usually automatically by KSPSolve() or KSPSetUp(),
33: but can be called directly by KSPSetUp().
35: */
36: PetscErrorCode KSPSetUp_LGMRES(KSP ksp) 37: {
39: PetscInt max_k,k, aug_dim;
40: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
43: max_k = lgmres->max_k;
44: aug_dim = lgmres->aug_dim;
45: KSPSetUp_GMRES(ksp);
47: /* need array of pointers to augvecs*/
48: PetscMalloc1(2*aug_dim + AUG_OFFSET,&lgmres->augvecs);
50: lgmres->aug_vecs_allocated = 2 *aug_dim + AUG_OFFSET;
52: PetscMalloc1(2*aug_dim + AUG_OFFSET,&lgmres->augvecs_user_work);
53: PetscMalloc1(aug_dim,&lgmres->aug_order);
54: PetscLogObjectMemory((PetscObject)ksp,(aug_dim)*(4*sizeof(void*) + sizeof(PetscInt)) + AUG_OFFSET*2*sizeof(void*));
56: /* for now we will preallocate the augvecs - because aug_dim << restart
57: ... also keep in mind that we need to keep augvecs from cycle to cycle*/
58: lgmres->aug_vv_allocated = 2* aug_dim + AUG_OFFSET;
59: lgmres->augwork_alloc = 2* aug_dim + AUG_OFFSET;
61: KSPCreateVecs(ksp,lgmres->aug_vv_allocated,&lgmres->augvecs_user_work[0],0,NULL);
62: PetscMalloc1(max_k+1,&lgmres->hwork);
63: PetscLogObjectParents(ksp,lgmres->aug_vv_allocated,lgmres->augvecs_user_work[0]);
64: for (k=0; k<lgmres->aug_vv_allocated; k++) {
65: lgmres->augvecs[k] = lgmres->augvecs_user_work[0][k];
66: }
67: return(0);
68: }
71: /*
73: KSPLGMRESCycle - Run lgmres, possibly with restart. Return residual
74: history if requested.
76: input parameters:
77: . lgmres - structure containing parameters and work areas
79: output parameters:
80: . nres - residuals (from preconditioned system) at each step.
81: If restarting, consider passing nres+it. If null,
82: ignored
83: . itcount - number of iterations used. nres[0] to nres[itcount]
84: are defined. If null, ignored. If null, ignored.
85: . converged - 0 if not converged
88: Notes:
89: On entry, the value in vector VEC_VV(0) should be
90: the initial residual.
93: */
94: PetscErrorCode KSPLGMRESCycle(PetscInt *itcount,KSP ksp) 95: {
96: KSP_LGMRES *lgmres = (KSP_LGMRES*)(ksp->data);
97: PetscReal res_norm, res;
98: PetscReal hapbnd, tt;
99: PetscScalar tmp;
100: PetscBool hapend = PETSC_FALSE; /* indicates happy breakdown ending */
102: PetscInt loc_it; /* local count of # of dir. in Krylov space */
103: PetscInt max_k = lgmres->max_k; /* max approx space size */
104: PetscInt max_it = ksp->max_it; /* max # of overall iterations for the method */
106: /* LGMRES_MOD - new variables*/
107: PetscInt aug_dim = lgmres->aug_dim;
108: PetscInt spot = 0;
109: PetscInt order = 0;
110: PetscInt it_arnoldi; /* number of arnoldi steps to take */
111: PetscInt it_total; /* total number of its to take (=approx space size)*/
112: PetscInt ii, jj;
113: PetscReal tmp_norm;
114: PetscScalar inv_tmp_norm;
115: PetscScalar *avec;
118: /* Number of pseudo iterations since last restart is the number
119: of prestart directions */
120: loc_it = 0;
122: /* LGMRES_MOD: determine number of arnoldi steps to take */
123: /* if approx_constant then we keep the space the same size even if
124: we don't have the full number of aug vectors yet*/
125: if (lgmres->approx_constant) it_arnoldi = max_k - lgmres->aug_ct;
126: else it_arnoldi = max_k - aug_dim;
128: it_total = it_arnoldi + lgmres->aug_ct;
130: /* initial residual is in VEC_VV(0) - compute its norm*/
131: VecNorm(VEC_VV(0),NORM_2,&res_norm);
132: KSPCheckNorm(ksp,res_norm);
133: res = res_norm;
135: /* first entry in right-hand-side of hessenberg system is just
136: the initial residual norm */
137: *GRS(0) = res_norm;
139: /* check for the convergence */
140: if (!res) {
141: if (itcount) *itcount = 0;
142: ksp->reason = KSP_CONVERGED_ATOL;
143: PetscInfo(ksp,"Converged due to zero residual norm on entry\n");
144: return(0);
145: }
147: /* scale VEC_VV (the initial residual) */
148: tmp = 1.0/res_norm; VecScale(VEC_VV(0),tmp);
150: if (ksp->normtype != KSP_NORM_NONE) ksp->rnorm = res;
151: else ksp->rnorm = 0.0;
154: /* note: (lgmres->it) is always set one less than (loc_it) It is used in
155: KSPBUILDSolution_LGMRES, where it is passed to KSPLGMRESBuildSoln.
156: Note that when KSPLGMRESBuildSoln is called from this function,
157: (loc_it -1) is passed, so the two are equivalent */
158: lgmres->it = (loc_it - 1);
161: /* MAIN ITERATION LOOP BEGINNING*/
164: /* keep iterating until we have converged OR generated the max number
165: of directions OR reached the max number of iterations for the method */
166: (*ksp->converged)(ksp,ksp->its,res,&ksp->reason,ksp->cnvP);
168: while (!ksp->reason && loc_it < it_total && ksp->its < max_it) { /* LGMRES_MOD: changed to it_total */
169: KSPLogResidualHistory(ksp,res);
170: lgmres->it = (loc_it - 1);
171: KSPMonitor(ksp,ksp->its,res);
173: /* see if more space is needed for work vectors */
174: if (lgmres->vv_allocated <= loc_it + VEC_OFFSET + 1) {
175: KSPLGMRESGetNewVectors(ksp,loc_it+1);
176: /* (loc_it+1) is passed in as number of the first vector that should
177: be allocated */
178: }
180: /*LGMRES_MOD: decide whether this is an arnoldi step or an aug step */
181: if (loc_it < it_arnoldi) { /* Arnoldi */
182: KSP_PCApplyBAorAB(ksp,VEC_VV(loc_it),VEC_VV(1+loc_it),VEC_TEMP_MATOP);
183: } else { /*aug step */
184: order = loc_it - it_arnoldi + 1; /* which aug step */
185: for (ii=0; ii<aug_dim; ii++) {
186: if (lgmres->aug_order[ii] == order) {
187: spot = ii;
188: break; /* must have this because there will be duplicates before aug_ct = aug_dim */
189: }
190: }
192: VecCopy(A_AUGVEC(spot), VEC_VV(1+loc_it));
193: /*note: an alternate implementation choice would be to only save the AUGVECS and
194: not A_AUGVEC and then apply the PC here to the augvec */
195: }
197: /* update hessenberg matrix and do Gram-Schmidt - new direction is in
198: VEC_VV(1+loc_it)*/
199: (*lgmres->orthog)(ksp,loc_it);
201: /* new entry in hessenburg is the 2-norm of our new direction */
202: VecNorm(VEC_VV(loc_it+1),NORM_2,&tt);
204: *HH(loc_it+1,loc_it) = tt;
205: *HES(loc_it+1,loc_it) = tt;
208: /* check for the happy breakdown */
209: hapbnd = PetscAbsScalar(tt / *GRS(loc_it)); /* GRS(loc_it) contains the res_norm from the last iteration */
210: if (hapbnd > lgmres->haptol) hapbnd = lgmres->haptol;
211: if (tt > hapbnd) {
212: tmp = 1.0/tt;
213: VecScale(VEC_VV(loc_it+1),tmp); /* scale new direction by its norm */
214: } else {
215: PetscInfo2(ksp,"Detected happy breakdown, current hapbnd = %g tt = %g\n",(double)hapbnd,(double)tt);
216: hapend = PETSC_TRUE;
217: }
219: /* Now apply rotations to new col of hessenberg (and right side of system),
220: calculate new rotation, and get new residual norm at the same time*/
221: KSPLGMRESUpdateHessenberg(ksp,loc_it,hapend,&res);
222: if (ksp->reason) break;
224: loc_it++;
225: lgmres->it = (loc_it-1); /* Add this here in case it has converged */
227: PetscObjectSAWsTakeAccess((PetscObject)ksp);
228: ksp->its++;
229: if (ksp->normtype != KSP_NORM_NONE) ksp->rnorm = res;
230: else ksp->rnorm = 0.0;
231: PetscObjectSAWsGrantAccess((PetscObject)ksp);
233: (*ksp->converged)(ksp,ksp->its,res,&ksp->reason,ksp->cnvP);
235: /* Catch error in happy breakdown and signal convergence and break from loop */
236: if (hapend) {
237: if (!ksp->reason) {
238: if (ksp->errorifnotconverged) SETERRQ1(PetscObjectComm((PetscObject)ksp),PETSC_ERR_NOT_CONVERGED,"You reached the happy break down, but convergence was not indicated. Residual norm = %g",(double)res);
239: else {
240: ksp->reason = KSP_DIVERGED_BREAKDOWN;
241: break;
242: }
243: }
244: }
245: }
246: /* END OF ITERATION LOOP */
247: KSPLogResidualHistory(ksp,res);
249: /* Monitor if we know that we will not return for a restart */
250: if (ksp->reason || ksp->its >= max_it) {
251: KSPMonitor(ksp, ksp->its, res);
252: }
254: if (itcount) *itcount = loc_it;
256: /*
257: Down here we have to solve for the "best" coefficients of the Krylov
258: columns, add the solution values together, and possibly unwind the
259: preconditioning from the solution
260: */
262: /* Form the solution (or the solution so far) */
263: /* Note: must pass in (loc_it-1) for iteration count so that KSPLGMRESBuildSoln
264: properly navigates */
266: KSPLGMRESBuildSoln(GRS(0),ksp->vec_sol,ksp->vec_sol,ksp,loc_it-1);
269: /* LGMRES_MOD collect aug vector and A*augvector for future restarts -
270: only if we will be restarting (i.e. this cycle performed it_total
271: iterations) */
272: if (!ksp->reason && ksp->its < max_it && aug_dim > 0) {
274: /*AUG_TEMP contains the new augmentation vector (assigned in KSPLGMRESBuildSoln) */
275: if (!lgmres->aug_ct) {
276: spot = 0;
277: lgmres->aug_ct++;
278: } else if (lgmres->aug_ct < aug_dim) {
279: spot = lgmres->aug_ct;
280: lgmres->aug_ct++;
281: } else { /* truncate */
282: for (ii=0; ii<aug_dim; ii++) {
283: if (lgmres->aug_order[ii] == aug_dim) spot = ii;
284: }
285: }
289: VecCopy(AUG_TEMP, AUGVEC(spot));
290: /*need to normalize */
291: VecNorm(AUGVEC(spot), NORM_2, &tmp_norm);
293: inv_tmp_norm = 1.0/tmp_norm;
295: VecScale(AUGVEC(spot),inv_tmp_norm);
297: /*set new aug vector to order 1 - move all others back one */
298: for (ii=0; ii < aug_dim; ii++) AUG_ORDER(ii)++;
299: AUG_ORDER(spot) = 1;
301: /*now add the A*aug vector to A_AUGVEC(spot) - this is independ. of preconditioning type*/
302: /* want V*H*y - y is in GRS, V is in VEC_VV and H is in HES */
305: /* first do H+*y */
306: avec = lgmres->hwork;
307: PetscArrayzero(avec,it_total+1);
308: for (ii=0; ii < it_total + 1; ii++) {
309: for (jj=0; jj <= ii+1 && jj < it_total+1; jj++) {
310: avec[jj] += *HES(jj ,ii) * *GRS(ii);
311: }
312: }
314: /*now multiply result by V+ */
315: VecSet(VEC_TEMP,0.0);
316: VecMAXPY(VEC_TEMP, it_total+1, avec, &VEC_VV(0)); /*answer is in VEC_TEMP*/
318: /*copy answer to aug location and scale*/
319: VecCopy(VEC_TEMP, A_AUGVEC(spot));
320: VecScale(A_AUGVEC(spot),inv_tmp_norm);
321: }
322: return(0);
323: }
325: /*
326: KSPSolve_LGMRES - This routine applies the LGMRES method.
329: Input Parameter:
330: . ksp - the Krylov space object that was set to use lgmres
332: Output Parameter:
333: . outits - number of iterations used
335: */
337: PetscErrorCode KSPSolve_LGMRES(KSP ksp)338: {
340: PetscInt cycle_its; /* iterations done in a call to KSPLGMRESCycle */
341: PetscInt itcount; /* running total of iterations, incl. those in restarts */
342: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
343: PetscBool guess_zero = ksp->guess_zero;
344: PetscInt ii; /*LGMRES_MOD variable */
347: if (ksp->calc_sings && !lgmres->Rsvd) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ORDER,"Must call KSPSetComputeSingularValues() before KSPSetUp() is called");
349: PetscObjectSAWsTakeAccess((PetscObject)ksp);
351: ksp->its = 0;
352: lgmres->aug_ct = 0;
353: lgmres->matvecs = 0;
355: PetscObjectSAWsGrantAccess((PetscObject)ksp);
357: /* initialize */
358: itcount = 0;
359: ksp->reason = KSP_CONVERGED_ITERATING;
360: /*LGMRES_MOD*/
361: for (ii=0; ii<lgmres->aug_dim; ii++) lgmres->aug_order[ii] = 0;
363: while (!ksp->reason) {
364: /* calc residual - puts in VEC_VV(0) */
365: KSPInitialResidual(ksp,ksp->vec_sol,VEC_TEMP,VEC_TEMP_MATOP,VEC_VV(0),ksp->vec_rhs);
366: KSPLGMRESCycle(&cycle_its,ksp);
367: itcount += cycle_its;
368: if (itcount >= ksp->max_it) {
369: if (!ksp->reason) ksp->reason = KSP_DIVERGED_ITS;
370: break;
371: }
372: ksp->guess_zero = PETSC_FALSE; /* every future call to KSPInitialResidual() will have nonzero guess */
373: }
374: ksp->guess_zero = guess_zero; /* restore if user provided nonzero initial guess */
375: return(0);
376: }
378: /*
380: KSPDestroy_LGMRES - Frees all memory space used by the Krylov method.
382: */
383: PetscErrorCode KSPDestroy_LGMRES(KSP ksp)384: {
385: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
389: PetscFree(lgmres->augvecs);
390: if (lgmres->augwork_alloc) {
391: VecDestroyVecs(lgmres->augwork_alloc,&lgmres->augvecs_user_work[0]);
392: }
393: PetscFree(lgmres->augvecs_user_work);
394: PetscFree(lgmres->aug_order);
395: PetscFree(lgmres->hwork);
396: KSPDestroy_GMRES(ksp);
397: return(0);
398: }
400: /*
401: KSPLGMRESBuildSoln - create the solution from the starting vector and the
402: current iterates.
404: Input parameters:
405: nrs - work area of size it + 1.
406: vguess - index of initial guess
407: vdest - index of result. Note that vguess may == vdest (replace
408: guess with the solution).
409: it - HH upper triangular part is a block of size (it+1) x (it+1)
411: This is an internal routine that knows about the LGMRES internals.
412: */
413: static PetscErrorCode KSPLGMRESBuildSoln(PetscScalar *nrs,Vec vguess,Vec vdest,KSP ksp,PetscInt it)414: {
415: PetscScalar tt;
417: PetscInt ii,k,j;
418: KSP_LGMRES *lgmres = (KSP_LGMRES*)(ksp->data);
419: /*LGMRES_MOD */
420: PetscInt it_arnoldi, it_aug;
421: PetscInt jj, spot = 0;
424: /* Solve for solution vector that minimizes the residual */
426: /* If it is < 0, no lgmres steps have been performed */
427: if (it < 0) {
428: VecCopy(vguess,vdest); /* VecCopy() is smart, exists immediately if vguess == vdest */
429: return(0);
430: }
432: /* so (it+1) lgmres steps HAVE been performed */
434: /* LGMRES_MOD - determine if we need to use augvecs for the soln - do not assume that
435: this is called after the total its allowed for an approx space */
436: if (lgmres->approx_constant) {
437: it_arnoldi = lgmres->max_k - lgmres->aug_ct;
438: } else {
439: it_arnoldi = lgmres->max_k - lgmres->aug_dim;
440: }
441: if (it_arnoldi >= it +1) {
442: it_aug = 0;
443: it_arnoldi = it+1;
444: } else {
445: it_aug = (it + 1) - it_arnoldi;
446: }
448: /* now it_arnoldi indicates the number of matvecs that took place */
449: lgmres->matvecs += it_arnoldi;
452: /* solve the upper triangular system - GRS is the right side and HH is
453: the upper triangular matrix - put soln in nrs */
454: if (*HH(it,it) == 0.0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_CONV_FAILED,"HH(it,it) is identically zero; it = %D GRS(it) = %g",it,(double)PetscAbsScalar(*GRS(it)));
455: if (*HH(it,it) != 0.0) {
456: nrs[it] = *GRS(it) / *HH(it,it);
457: } else {
458: nrs[it] = 0.0;
459: }
461: for (ii=1; ii<=it; ii++) {
462: k = it - ii;
463: tt = *GRS(k);
464: for (j=k+1; j<=it; j++) tt = tt - *HH(k,j) * nrs[j];
465: nrs[k] = tt / *HH(k,k);
466: }
468: /* Accumulate the correction to the soln of the preconditioned prob. in VEC_TEMP */
469: VecSet(VEC_TEMP,0.0); /* set VEC_TEMP components to 0 */
471: /*LGMRES_MOD - if augmenting has happened we need to form the solution
472: using the augvecs */
473: if (!it_aug) { /* all its are from arnoldi */
474: VecMAXPY(VEC_TEMP,it+1,nrs,&VEC_VV(0));
475: } else { /*use aug vecs */
476: /*first do regular krylov directions */
477: VecMAXPY(VEC_TEMP,it_arnoldi,nrs,&VEC_VV(0));
478: /*now add augmented portions - add contribution of aug vectors one at a time*/
481: for (ii=0; ii<it_aug; ii++) {
482: for (jj=0; jj<lgmres->aug_dim; jj++) {
483: if (lgmres->aug_order[jj] == (ii+1)) {
484: spot = jj;
485: break; /* must have this because there will be duplicates before aug_ct = aug_dim */
486: }
487: }
488: VecAXPY(VEC_TEMP,nrs[it_arnoldi+ii],AUGVEC(spot));
489: }
490: }
491: /* now VEC_TEMP is what we want to keep for augmenting purposes - grab before the
492: preconditioner is "unwound" from right-precondtioning*/
493: VecCopy(VEC_TEMP, AUG_TEMP);
495: KSPUnwindPreconditioner(ksp,VEC_TEMP,VEC_TEMP_MATOP);
497: /* add solution to previous solution */
498: /* put updated solution into vdest.*/
499: VecCopy(vguess,vdest);
500: VecAXPY(vdest,1.0,VEC_TEMP);
501: return(0);
502: }
504: /*
506: KSPLGMRESUpdateHessenberg - Do the scalar work for the orthogonalization.
507: Return new residual.
509: input parameters:
511: . ksp - Krylov space object
512: . it - plane rotations are applied to the (it+1)th column of the
513: modified hessenberg (i.e. HH(:,it))
514: . hapend - PETSC_FALSE not happy breakdown ending.
516: output parameters:
517: . res - the new residual
519: */
520: static PetscErrorCode KSPLGMRESUpdateHessenberg(KSP ksp,PetscInt it,PetscBool hapend,PetscReal *res)521: {
522: PetscScalar *hh,*cc,*ss,tt;
523: PetscInt j;
524: KSP_LGMRES *lgmres = (KSP_LGMRES*)(ksp->data);
527: hh = HH(0,it); /* pointer to beginning of column to update - so
528: incrementing hh "steps down" the (it+1)th col of HH*/
529: cc = CC(0); /* beginning of cosine rotations */
530: ss = SS(0); /* beginning of sine rotations */
532: /* Apply all the previously computed plane rotations to the new column
533: of the Hessenberg matrix */
534: /* Note: this uses the rotation [conj(c) s ; -s c], c= cos(theta), s= sin(theta) */
536: for (j=1; j<=it; j++) {
537: tt = *hh;
538: *hh = PetscConj(*cc) * tt + *ss * *(hh+1);
539: hh++;
540: *hh = *cc++ * *hh - (*ss++ * tt);
541: /* hh, cc, and ss have all been incremented one by end of loop */
542: }
544: /*
545: compute the new plane rotation, and apply it to:
546: 1) the right-hand-side of the Hessenberg system (GRS)
547: note: it affects GRS(it) and GRS(it+1)
548: 2) the new column of the Hessenberg matrix
549: note: it affects HH(it,it) which is currently pointed to
550: by hh and HH(it+1, it) (*(hh+1))
551: thus obtaining the updated value of the residual...
552: */
554: /* compute new plane rotation */
556: if (!hapend) {
557: tt = PetscSqrtScalar(PetscConj(*hh) * *hh + PetscConj(*(hh+1)) * *(hh+1));
558: if (tt == 0.0) {
559: ksp->reason = KSP_DIVERGED_NULL;
560: return(0);
561: }
562: *cc = *hh / tt; /* new cosine value */
563: *ss = *(hh+1) / tt; /* new sine value */
565: /* apply to 1) and 2) */
566: *GRS(it+1) = -(*ss * *GRS(it));
567: *GRS(it) = PetscConj(*cc) * *GRS(it);
568: *hh = PetscConj(*cc) * *hh + *ss * *(hh+1);
570: /* residual is the last element (it+1) of right-hand side! */
571: *res = PetscAbsScalar(*GRS(it+1));
573: } else { /* happy breakdown: HH(it+1, it) = 0, therfore we don't need to apply
574: another rotation matrix (so RH doesn't change). The new residual is
575: always the new sine term times the residual from last time (GRS(it)),
576: but now the new sine rotation would be zero...so the residual should
577: be zero...so we will multiply "zero" by the last residual. This might
578: not be exactly what we want to do here -could just return "zero". */
580: *res = 0.0;
581: }
582: return(0);
583: }
585: /*
587: KSPLGMRESGetNewVectors - This routine allocates more work vectors, starting from
588: VEC_VV(it)
590: */
591: static PetscErrorCode KSPLGMRESGetNewVectors(KSP ksp,PetscInt it)592: {
593: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
594: PetscInt nwork = lgmres->nwork_alloc; /* number of work vector chunks allocated */
595: PetscInt nalloc; /* number to allocate */
597: PetscInt k;
600: nalloc = lgmres->delta_allocate; /* number of vectors to allocate
601: in a single chunk */
603: /* Adjust the number to allocate to make sure that we don't exceed the
604: number of available slots (lgmres->vecs_allocated)*/
605: if (it + VEC_OFFSET + nalloc >= lgmres->vecs_allocated) {
606: nalloc = lgmres->vecs_allocated - it - VEC_OFFSET;
607: }
608: if (!nalloc) return(0);
610: lgmres->vv_allocated += nalloc; /* vv_allocated is the number of vectors allocated */
612: /* work vectors */
613: KSPCreateVecs(ksp,nalloc,&lgmres->user_work[nwork],0,NULL);
614: PetscLogObjectParents(ksp,nalloc,lgmres->user_work[nwork]);
615: /* specify size of chunk allocated */
616: lgmres->mwork_alloc[nwork] = nalloc;
618: for (k=0; k < nalloc; k++) {
619: lgmres->vecs[it+VEC_OFFSET+k] = lgmres->user_work[nwork][k];
620: }
623: /* LGMRES_MOD - for now we are preallocating the augmentation vectors */
626: /* increment the number of work vector chunks */
627: lgmres->nwork_alloc++;
628: return(0);
629: }
631: /*
633: KSPBuildSolution_LGMRES
635: Input Parameter:
636: . ksp - the Krylov space object
637: . ptr-
639: Output Parameter:
640: . result - the solution
642: Note: this calls KSPLGMRESBuildSoln - the same function that KSPLGMRESCycle
643: calls directly.
645: */
646: PetscErrorCode KSPBuildSolution_LGMRES(KSP ksp,Vec ptr,Vec *result)647: {
648: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
652: if (!ptr) {
653: if (!lgmres->sol_temp) {
654: VecDuplicate(ksp->vec_sol,&lgmres->sol_temp);
655: PetscLogObjectParent((PetscObject)ksp,(PetscObject)lgmres->sol_temp);
656: }
657: ptr = lgmres->sol_temp;
658: }
659: if (!lgmres->nrs) {
660: /* allocate the work area */
661: PetscMalloc1(lgmres->max_k,&lgmres->nrs);
662: PetscLogObjectMemory((PetscObject)ksp,lgmres->max_k*sizeof(PetscScalar));
663: }
665: KSPLGMRESBuildSoln(lgmres->nrs,ksp->vec_sol,ptr,ksp,lgmres->it);
666: if (result) *result = ptr;
667: return(0);
668: }
670: PetscErrorCode KSPView_LGMRES(KSP ksp,PetscViewer viewer)671: {
672: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
674: PetscBool iascii;
677: KSPView_GMRES(ksp,viewer);
678: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
679: if (iascii) {
680: /*LGMRES_MOD */
681: PetscViewerASCIIPrintf(viewer," aug. dimension=%D\n",lgmres->aug_dim);
682: if (lgmres->approx_constant) {
683: PetscViewerASCIIPrintf(viewer," approx. space size was kept constant.\n");
684: }
685: PetscViewerASCIIPrintf(viewer," number of matvecs=%D\n",lgmres->matvecs);
686: }
687: return(0);
688: }
690: PetscErrorCode KSPSetFromOptions_LGMRES(PetscOptionItems *PetscOptionsObject,KSP ksp)691: {
693: PetscInt aug;
694: KSP_LGMRES *lgmres = (KSP_LGMRES*) ksp->data;
695: PetscBool flg = PETSC_FALSE;
698: KSPSetFromOptions_GMRES(PetscOptionsObject,ksp);
699: PetscOptionsHead(PetscOptionsObject,"KSP LGMRES Options");
700: PetscOptionsBool("-ksp_lgmres_constant","Use constant approx. space size","KSPGMRESSetConstant",lgmres->approx_constant,&lgmres->approx_constant,NULL);
701: PetscOptionsInt("-ksp_lgmres_augment","Number of error approximations to augment the Krylov space with","KSPLGMRESSetAugDim",lgmres->aug_dim,&aug,&flg);
702: if (flg) { KSPLGMRESSetAugDim(ksp,aug); }
703: PetscOptionsTail();
704: return(0);
705: }
707: /*functions for extra lgmres options here*/
708: static PetscErrorCode KSPLGMRESSetConstant_LGMRES(KSP ksp)709: {
710: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
713: lgmres->approx_constant = PETSC_TRUE;
714: return(0);
715: }
717: static PetscErrorCode KSPLGMRESSetAugDim_LGMRES(KSP ksp,PetscInt aug_dim)718: {
719: KSP_LGMRES *lgmres = (KSP_LGMRES*)ksp->data;
722: if (aug_dim < 0) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_OUTOFRANGE,"Augmentation dimension must be positive");
723: if (aug_dim > (lgmres->max_k -1)) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_OUTOFRANGE,"Augmentation dimension must be <= (restart size-1)");
724: lgmres->aug_dim = aug_dim;
725: return(0);
726: }
728: /* end new lgmres functions */
730: /*MC
731: KSPLGMRES - Augments the standard GMRES approximation space with approximations to
732: the error from previous restart cycles.
734: Options Database Keys:
735: + -ksp_gmres_restart <restart> - total approximation space size (Krylov directions + error approximations)
736: . -ksp_gmres_haptol <tol> - sets the tolerance for "happy ending" (exact convergence)
737: . -ksp_gmres_preallocate - preallocate all the Krylov search directions initially (otherwise groups of
738: vectors are allocated as needed)
739: . -ksp_gmres_classicalgramschmidt - use classical (unmodified) Gram-Schmidt to orthogonalize against the Krylov space (fast) (the default)
740: . -ksp_gmres_modifiedgramschmidt - use modified Gram-Schmidt in the orthogonalization (more stable, but slower)
741: . -ksp_gmres_cgs_refinement_type <refine_never,refine_ifneeded,refine_always> - determine if iterative refinement is used to increase the
742: stability of the classical Gram-Schmidt orthogonalization.
743: . -ksp_gmres_krylov_monitor - plot the Krylov space generated
744: . -ksp_lgmres_augment <k> - number of error approximations to augment the Krylov space with
745: - -ksp_lgmres_constant - use a constant approx. space size (only affects restart cycles < num. error approx.(k), i.e. the first k restarts)
747: To run LGMRES(m, k) as described in the above paper, use:
748: -ksp_gmres_restart <m+k>
749: -ksp_lgmres_augment <k>
751: Level: beginner
753: Notes:
754: Supports both left and right preconditioning, but not symmetric.
756: References:
757: . 1. - A. H. Baker, E.R. Jessup, and T.A. Manteuffel. A technique for accelerating the convergence of restarted GMRES. SIAM Journal on Matrix Analysis and Applications, 26 (2005).
759: Developer Notes:
760: This object is subclassed off of KSPGMRES762: Contributed by: Allison Baker
764: .seealso: KSPCreate(), KSPSetType(), KSPType (for list of available types), KSP, KSPFGMRES, KSPGMRES,
765: KSPGMRESSetRestart(), KSPGMRESSetHapTol(), KSPGMRESSetPreAllocateVectors(), KSPGMRESSetOrthogonalization(), KSPGMRESGetOrthogonalization(),
766: KSPGMRESClassicalGramSchmidtOrthogonalization(), KSPGMRESModifiedGramSchmidtOrthogonalization(),
767: KSPGMRESCGSRefinementType, KSPGMRESSetCGSRefinementType(), KSPGMRESGetCGSRefinementType(), KSPGMRESMonitorKrylov(), KSPLGMRESSetAugDim(),
768: KSPGMRESSetConstant()
770: M*/
772: PETSC_EXTERN PetscErrorCode KSPCreate_LGMRES(KSP ksp)773: {
774: KSP_LGMRES *lgmres;
778: PetscNewLog(ksp,&lgmres);
780: ksp->data = (void*)lgmres;
781: ksp->ops->buildsolution = KSPBuildSolution_LGMRES;
783: ksp->ops->setup = KSPSetUp_LGMRES;
784: ksp->ops->solve = KSPSolve_LGMRES;
785: ksp->ops->destroy = KSPDestroy_LGMRES;
786: ksp->ops->view = KSPView_LGMRES;
787: ksp->ops->setfromoptions = KSPSetFromOptions_LGMRES;
788: ksp->ops->computeextremesingularvalues = KSPComputeExtremeSingularValues_GMRES;
789: ksp->ops->computeeigenvalues = KSPComputeEigenvalues_GMRES;
791: KSPSetSupportedNorm(ksp,KSP_NORM_PRECONDITIONED,PC_LEFT,3);
792: KSPSetSupportedNorm(ksp,KSP_NORM_UNPRECONDITIONED,PC_RIGHT,2);
793: KSPSetSupportedNorm(ksp,KSP_NORM_NONE,PC_RIGHT,1);
795: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESSetPreAllocateVectors_C",KSPGMRESSetPreAllocateVectors_GMRES);
796: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESSetOrthogonalization_C",KSPGMRESSetOrthogonalization_GMRES);
797: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESGetOrthogonalization_C",KSPGMRESGetOrthogonalization_GMRES);
798: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESSetRestart_C",KSPGMRESSetRestart_GMRES);
799: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESGetRestart_C",KSPGMRESGetRestart_GMRES);
800: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESSetHapTol_C",KSPGMRESSetHapTol_GMRES);
801: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESSetCGSRefinementType_C",KSPGMRESSetCGSRefinementType_GMRES);
802: PetscObjectComposeFunction((PetscObject)ksp,"KSPGMRESGetCGSRefinementType_C",KSPGMRESGetCGSRefinementType_GMRES);
804: /*LGMRES_MOD add extra functions here - like the one to set num of aug vectors */
805: PetscObjectComposeFunction((PetscObject)ksp,"KSPLGMRESSetConstant_C",KSPLGMRESSetConstant_LGMRES);
806: PetscObjectComposeFunction((PetscObject)ksp,"KSPLGMRESSetAugDim_C",KSPLGMRESSetAugDim_LGMRES);
809: /*defaults */
810: lgmres->haptol = 1.0e-30;
811: lgmres->q_preallocate = 0;
812: lgmres->delta_allocate = LGMRES_DELTA_DIRECTIONS;
813: lgmres->orthog = KSPGMRESClassicalGramSchmidtOrthogonalization;
814: lgmres->nrs = NULL;
815: lgmres->sol_temp = NULL;
816: lgmres->max_k = LGMRES_DEFAULT_MAXK;
817: lgmres->Rsvd = NULL;
818: lgmres->cgstype = KSP_GMRES_CGS_REFINE_NEVER;
819: lgmres->orthogwork = NULL;
821: /*LGMRES_MOD - new defaults */
822: lgmres->aug_dim = LGMRES_DEFAULT_AUGDIM;
823: lgmres->aug_ct = 0; /* start with no aug vectors */
824: lgmres->approx_constant = PETSC_FALSE;
825: lgmres->matvecs = 0;
826: return(0);
827: }