Actual source code: nleigs.c

  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:    SLEPc nonlinear eigensolver: "nleigs"

 13:    Method: NLEIGS

 15:    Algorithm:

 17:        Fully rational Krylov method for nonlinear eigenvalue problems.

 19:    References:

 21:        [1] S. Guttel et al., "NLEIGS: A class of robust fully rational Krylov
 22:            method for nonlinear eigenvalue problems", SIAM J. Sci. Comput.
 23:            36(6):A2842-A2864, 2014.
 24: */

 26: #include <slepc/private/nepimpl.h>
 27: #include <slepcblaslapack.h>
 28: #include "nleigs.h"

 30: PetscErrorCode NEPNLEIGSBackTransform(PetscObject ob,PetscInt n,PetscScalar *valr,PetscScalar *vali)
 31: {
 32:   NEP         nep;
 33:   PetscInt    j;
 34: #if !PetscDefined(USE_COMPLEX)
 35:   PetscScalar t;
 36: #endif

 38:   PetscFunctionBegin;
 39:   nep = (NEP)ob;
 40: #if !PetscDefined(USE_COMPLEX)
 41:   for (j=0;j<n;j++) {
 42:     if (vali[j] == 0) valr[j] = 1.0 / valr[j] + nep->target;
 43:     else {
 44:       t = valr[j] * valr[j] + vali[j] * vali[j];
 45:       valr[j] = valr[j] / t + nep->target;
 46:       vali[j] = - vali[j] / t;
 47:     }
 48:   }
 49: #else
 50:   for (j=0;j<n;j++) {
 51:     valr[j] = 1.0 / valr[j] + nep->target;
 52:   }
 53: #endif
 54:   PetscFunctionReturn(PETSC_SUCCESS);
 55: }

 57: /* Computes the roots of a polynomial */
 58: static PetscErrorCode NEPNLEIGSAuxiliarPRootFinder(PetscInt deg,PetscScalar *polcoeffs,PetscScalar *wr,PetscScalar *wi,PetscBool *avail)
 59: {
 60:   PetscScalar    *C;
 61:   PetscBLASInt   n_,lwork;
 62:   PetscInt       i;
 63: #if PetscDefined(USE_COMPLEX)
 64:   PetscReal      *rwork=NULL;
 65: #endif
 66:   PetscScalar    *work;
 67:   PetscBLASInt   info;

 69:   PetscFunctionBegin;
 70:   *avail = PETSC_TRUE;
 71:   if (deg>0) {
 72:     PetscCall(PetscCalloc1(deg*deg,&C));
 73:     PetscCall(PetscBLASIntCast(deg,&n_));
 74:     for (i=0;i<deg-1;i++) {
 75:       C[(deg+1)*i+1]   = 1.0;
 76:       C[(deg-1)*deg+i] = -polcoeffs[deg-i]/polcoeffs[0];
 77:     }
 78:     C[deg*deg+-1] = -polcoeffs[1]/polcoeffs[0];
 79:     PetscCall(PetscBLASIntCast(3*deg,&lwork));

 81:     PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
 82: #if !PetscDefined(USE_COMPLEX)
 83:     PetscCall(PetscMalloc1(lwork,&work));
 84:     PetscCallBLAS("LAPACKgeev",LAPACKgeev_("N","N",&n_,C,&n_,wr,wi,NULL,&n_,NULL,&n_,work,&lwork,&info));
 85:     if (info) *avail = PETSC_FALSE;
 86:     PetscCall(PetscFree(work));
 87: #else
 88:     PetscCall(PetscMalloc2(2*deg,&rwork,lwork,&work));
 89:     PetscCallBLAS("LAPACKgeev",LAPACKgeev_("N","N",&n_,C,&n_,wr,NULL,&n_,NULL,&n_,work,&lwork,rwork,&info));
 90:     if (info) *avail = PETSC_FALSE;
 91:     PetscCall(PetscFree2(rwork,work));
 92: #endif
 93:     PetscCall(PetscFPTrapPop());
 94:     PetscCall(PetscFree(C));
 95:   }
 96:   PetscFunctionReturn(PETSC_SUCCESS);
 97: }

 99: static PetscErrorCode NEPNLEIGSAuxiliarRmDuplicates(PetscInt nin,PetscScalar *pin,PetscInt *nout,PetscScalar *pout,PetscInt max)
100: {
101:   PetscInt i,j;

103:   PetscFunctionBegin;
104:   for (i=0;i<nin;i++) {
105:     if (max && *nout>=max) break;
106:     pout[(*nout)++] = pin[i];
107:     for (j=0;j<*nout-1;j++)
108:       if (PetscAbsScalar(pin[i]-pout[j])<PETSC_MACHINE_EPSILON*100) {
109:         (*nout)--;
110:         break;
111:       }
112:   }
113:   PetscFunctionReturn(PETSC_SUCCESS);
114: }

116: static PetscErrorCode NEPNLEIGSFNSingularities(FN f,PetscInt *nisol,PetscScalar **isol,PetscBool *rational)
117: {
118:   FNCombineType  ctype;
119:   FN             f1,f2;
120:   PetscInt       i,nq,nisol1,nisol2;
121:   PetscScalar    *qcoeff,*wr,*wi,*isol1,*isol2;
122:   PetscBool      flg,avail,rat1,rat2;

124:   PetscFunctionBegin;
125:   *rational = PETSC_FALSE;
126:   PetscCall(PetscObjectTypeCompare((PetscObject)f,FNRATIONAL,&flg));
127:   if (flg) {
128:     *rational = PETSC_TRUE;
129:     PetscCall(FNRationalGetDenominator(f,&nq,&qcoeff));
130:     if (nq>1) {
131:       PetscCall(PetscMalloc2(nq-1,&wr,nq-1,&wi));
132:       PetscCall(NEPNLEIGSAuxiliarPRootFinder(nq-1,qcoeff,wr,wi,&avail));
133:       if (avail) {
134:         PetscCall(PetscCalloc1(nq-1,isol));
135:         *nisol = 0;
136:         for (i=0;i<nq-1;i++)
137: #if !PetscDefined(USE_COMPLEX)
138:           if (wi[i]==0)
139: #endif
140:             (*isol)[(*nisol)++] = wr[i];
141:         nq = *nisol; *nisol = 0;
142:         for (i=0;i<nq;i++) wr[i] = (*isol)[i];
143:         PetscCall(NEPNLEIGSAuxiliarRmDuplicates(nq,wr,nisol,*isol,0));
144:         PetscCall(PetscFree2(wr,wi));
145:       } else { *nisol=0; *isol = NULL; }
146:     } else { *nisol = 0; *isol = NULL; }
147:     PetscCall(PetscFree(qcoeff));
148:   }
149:   PetscCall(PetscObjectTypeCompare((PetscObject)f,FNCOMBINE,&flg));
150:   if (flg) {
151:     PetscCall(FNCombineGetChildren(f,&ctype,&f1,&f2));
152:     if (ctype != FN_COMBINE_COMPOSE && ctype != FN_COMBINE_DIVIDE) {
153:       PetscCall(NEPNLEIGSFNSingularities(f1,&nisol1,&isol1,&rat1));
154:       PetscCall(NEPNLEIGSFNSingularities(f2,&nisol2,&isol2,&rat2));
155:       if (nisol1+nisol2>0) {
156:         PetscCall(PetscCalloc1(nisol1+nisol2,isol));
157:         *nisol = 0;
158:         PetscCall(NEPNLEIGSAuxiliarRmDuplicates(nisol1,isol1,nisol,*isol,0));
159:         PetscCall(NEPNLEIGSAuxiliarRmDuplicates(nisol2,isol2,nisol,*isol,0));
160:       }
161:       *rational = (rat1&&rat2)?PETSC_TRUE:PETSC_FALSE;
162:       PetscCall(PetscFree(isol1));
163:       PetscCall(PetscFree(isol2));
164:     }
165:   }
166:   PetscFunctionReturn(PETSC_SUCCESS);
167: }

169: static PetscErrorCode NEPNLEIGSRationalSingularities(NEP nep,PetscInt *ndptx,PetscScalar *dxi,PetscBool *rational)
170: {
171:   PetscInt       nt,i,nisol;
172:   FN             f;
173:   PetscScalar    *isol;
174:   PetscBool      rat;

176:   PetscFunctionBegin;
177:   *rational = PETSC_TRUE;
178:   *ndptx = 0;
179:   PetscCall(NEPGetSplitOperatorInfo(nep,&nt,NULL));
180:   for (i=0;i<nt;i++) {
181:     PetscCall(NEPGetSplitOperatorTerm(nep,i,NULL,&f));
182:     PetscCall(NEPNLEIGSFNSingularities(f,&nisol,&isol,&rat));
183:     if (nisol) {
184:       PetscCall(NEPNLEIGSAuxiliarRmDuplicates(nisol,isol,ndptx,dxi,0));
185:       PetscCall(PetscFree(isol));
186:     }
187:     *rational = ((*rational)&&rat)?PETSC_TRUE:PETSC_FALSE;
188:   }
189:   PetscFunctionReturn(PETSC_SUCCESS);
190: }

192: #if defined(SLEPC_MISSING_LAPACK_GGEV3)
193: #define LAPGEEV "ggev"
194: #else
195: #define LAPGEEV "ggev3"
196: #endif

198: /*  Adaptive Anderson-Antoulas algorithm */
199: static PetscErrorCode NEPNLEIGSAAAComputation(NEP nep,PetscInt ndpt,PetscScalar *ds,PetscScalar *F,PetscInt *ndptx,PetscScalar *dxi)
200: {
201:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
202:   PetscScalar    mean=0.0,*z,*f,*C,*A,*VT,*work,*ww,szero=0.0,sone=1.0;
203:   PetscScalar    *N,*D;
204:   PetscReal      *S,norm,err,*R;
205:   PetscInt       i,k,j,idx=0,cont;
206:   PetscBLASInt   n_,m_,lda_,lwork,one=1;
207: #if PetscDefined(USE_COMPLEX)
208:   PetscReal      *rwork;
209: #endif

211:   PetscFunctionBegin;
212:   PetscCall(PetscBLASIntCast(8*ndpt,&lwork));
213:   PetscCall(PetscMalloc5(ndpt,&R,ndpt,&z,ndpt,&f,ndpt*ndpt,&C,ndpt,&ww));
214:   PetscCall(PetscMalloc6(ndpt*ndpt,&A,ndpt,&S,ndpt*ndpt,&VT,lwork,&work,ndpt,&D,ndpt,&N));
215: #if PetscDefined(USE_COMPLEX)
216:   PetscCall(PetscMalloc1(8*ndpt,&rwork));
217: #endif
218:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
219:   norm = 0.0;
220:   for (i=0;i<ndpt;i++) {
221:     mean += F[i];
222:     norm = PetscMax(PetscAbsScalar(F[i]),norm);
223:   }
224:   mean /= ndpt;
225:   PetscCall(PetscBLASIntCast(ndpt,&lda_));
226:   for (i=0;i<ndpt;i++) R[i] = PetscAbsScalar(F[i]-mean);
227:   /* next support point */
228:   err = 0.0;
229:   for (i=0;i<ndpt;i++) if (R[i]>=err) {idx = i; err = R[i];}
230:   for (k=0;k<ndpt-1;k++) {
231:     z[k] = ds[idx]; f[k] = F[idx]; R[idx] = -1.0;
232:     /* next column of Cauchy matrix */
233:     for (i=0;i<ndpt;i++) {
234:       C[i+k*ndpt] = 1.0/(ds[i]-ds[idx]);
235:     }

237:     PetscCall(PetscArrayzero(A,ndpt*ndpt));
238:     cont = 0;
239:     for (i=0;i<ndpt;i++) {
240:       if (R[i]!=-1.0) {
241:         for (j=0;j<=k;j++)A[cont+j*ndpt] = C[i+j*ndpt]*F[i]-C[i+j*ndpt]*f[j];
242:         cont++;
243:       }
244:     }
245:     PetscCall(PetscBLASIntCast(cont,&m_));
246:     PetscCall(PetscBLASIntCast(k+1,&n_));
247: #if PetscDefined(USE_COMPLEX)
248:     PetscCallLAPACKInfo("LAPACKgesvd",LAPACKgesvd_("N","A",&m_,&n_,A,&lda_,S,NULL,&lda_,VT,&lda_,work,&lwork,rwork,&info));
249: #else
250:     PetscCallLAPACKInfo("LAPACKgesvd",LAPACKgesvd_("N","A",&m_,&n_,A,&lda_,S,NULL,&lda_,VT,&lda_,work,&lwork,&info));
251: #endif
252:     for (i=0;i<=k;i++) {
253:       ww[i] = PetscConj(VT[i*ndpt+k]);
254:       D[i] = ww[i]*f[i];
255:     }
256:     PetscCallBLAS("BLASgemv",BLASgemv_("N",&lda_,&n_,&sone,C,&lda_,D,&one,&szero,N,&one));
257:     PetscCallBLAS("BLASgemv",BLASgemv_("N",&lda_,&n_,&sone,C,&lda_,ww,&one,&szero,D,&one));
258:     for (i=0;i<ndpt;i++) if (R[i]>=0) R[i] = PetscAbsScalar(F[i]-N[i]/D[i]);
259:     /* next support point */
260:     err = 0.0;
261:     for (i=0;i<ndpt;i++) if (R[i]>=err) {idx = i; err = R[i];}
262:     if (err <= ctx->ddtol*norm) break;
263:   }

265:   PetscCheck(k<ndpt-1,PetscObjectComm((PetscObject)nep),PETSC_ERR_CONV_FAILED,"Failed to determine singularities automatically in general problem");
266:   /* poles */
267:   PetscCall(PetscArrayzero(C,ndpt*ndpt));
268:   PetscCall(PetscArrayzero(A,ndpt*ndpt));
269:   for (i=0;i<=k;i++) {
270:     C[i+ndpt*i] = 1.0;
271:     A[(i+1)*ndpt] = ww[i];
272:     A[i+1] = 1.0;
273:     A[i+1+(i+1)*ndpt] = z[i];
274:   }
275:   C[0] = 0.0; C[k+1+(k+1)*ndpt] = 1.0;
276:   n_++;
277: #if PetscDefined(USE_COMPLEX)
278:   PetscCallLAPACKInfo("LAPACK" LAPGEEV,LAPACKggevalt_("N","N",&n_,A,&lda_,C,&lda_,D,N,NULL,&lda_,NULL,&lda_,work,&lwork,rwork,&info));
279: #else
280:   PetscCallLAPACKInfo("LAPACK" LAPGEEV,LAPACKggevalt_("N","N",&n_,A,&lda_,C,&lda_,D,VT,N,NULL,&lda_,NULL,&lda_,work,&lwork,&info));
281: #endif
282:   cont = 0.0;
283:   for (i=0;i<n_;i++) if (N[i]!=0.0) {
284:     dxi[cont++] = D[i]/N[i];
285:   }
286:   *ndptx = cont;
287:   PetscCall(PetscFPTrapPop());
288:   PetscCall(PetscFree5(R,z,f,C,ww));
289:   PetscCall(PetscFree6(A,S,VT,work,D,N));
290: #if PetscDefined(USE_COMPLEX)
291:   PetscCall(PetscFree(rwork));
292: #endif
293:   PetscFunctionReturn(PETSC_SUCCESS);
294: }

296: /*  Singularities using Adaptive Anderson-Antoulas algorithm */
297: static PetscErrorCode NEPNLEIGSAAASingularities(NEP nep,PetscInt ndpt,PetscScalar *ds,PetscInt *ndptx,PetscScalar *dxi)
298: {
299:   Vec            u,v,w;
300:   PetscRandom    rand=NULL;
301:   PetscScalar    *F,*isol;
302:   PetscInt       i,k,nisol,nt;
303:   Mat            T;
304:   FN             f;

306:   PetscFunctionBegin;
307:   PetscCall(PetscMalloc1(ndpt,&F));
308:   if (nep->fui==NEP_USER_INTERFACE_SPLIT) {
309:     PetscCall(PetscMalloc1(ndpt,&isol));
310:     *ndptx = 0;
311:     PetscCall(NEPGetSplitOperatorInfo(nep,&nt,NULL));
312:     nisol = *ndptx;
313:     for (k=0;k<nt;k++) {
314:       PetscCall(NEPGetSplitOperatorTerm(nep,k,NULL,&f));
315:       for (i=0;i<ndpt;i++) PetscCall(FNEvaluateFunction(f,ds[i],&F[i]));
316:       PetscCall(NEPNLEIGSAAAComputation(nep,ndpt,ds,F,&nisol,isol));
317:       if (nisol) PetscCall(NEPNLEIGSAuxiliarRmDuplicates(nisol,isol,ndptx,dxi,ndpt));
318:     }
319:     PetscCall(PetscFree(isol));
320:   } else {
321:     PetscCall(MatCreateVecs(nep->function,&u,NULL));
322:     PetscCall(VecDuplicate(u,&v));
323:     PetscCall(VecDuplicate(u,&w));
324:     if (nep->V) PetscCall(BVGetRandomContext(nep->V,&rand));
325:     PetscCall(VecSetRandom(u,rand));
326:     PetscCall(VecNormalize(u,NULL));
327:     PetscCall(VecSetRandom(v,rand));
328:     PetscCall(VecNormalize(v,NULL));
329:     T = nep->function;
330:     for (i=0;i<ndpt;i++) {
331:       PetscCall(NEPComputeFunction(nep,ds[i],T,T));
332:       PetscCall(MatMult(T,v,w));
333:       PetscCall(VecDot(w,u,&F[i]));
334:     }
335:     PetscCall(NEPNLEIGSAAAComputation(nep,ndpt,ds,F,ndptx,dxi));
336:     PetscCall(VecDestroy(&u));
337:     PetscCall(VecDestroy(&v));
338:     PetscCall(VecDestroy(&w));
339:   }
340:   PetscCall(PetscFree(F));
341:   PetscFunctionReturn(PETSC_SUCCESS);
342: }

344: static PetscErrorCode NEPNLEIGSLejaBagbyPoints(NEP nep)
345: {
346:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
347:   PetscInt       i,k,ndpt=NDPOINTS,ndptx=NDPOINTS;
348:   PetscScalar    *ds,*dsi,*dxi,*nrs,*nrxi,*s=ctx->s,*xi=ctx->xi,*beta=ctx->beta;
349:   PetscReal      maxnrs,minnrxi;
350:   PetscBool      rational;
351: #if !PetscDefined(USE_COMPLEX)
352:   PetscReal      a,b,h;
353: #endif

355:   PetscFunctionBegin;
356:   if (!ctx->computesingularities && nep->problem_type!=NEP_RATIONAL) ndpt = ndptx = LBPOINTS;
357:   PetscCall(PetscMalloc5(ndpt+1,&ds,ndpt+1,&dsi,ndpt,&dxi,ndpt+1,&nrs,ndpt,&nrxi));

359:   /* Discretize the target region boundary */
360:   PetscCall(RGComputeContour(nep->rg,ndpt,ds,dsi));
361: #if !PetscDefined(USE_COMPLEX)
362:   for (i=0;i<ndpt;i++) if (dsi[i]!=0.0) break;
363:   if (i<ndpt) {
364:     PetscCheck(nep->problem_type==NEP_RATIONAL,PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"NLEIGS with real arithmetic requires the target set to be included in the real axis");
365:     /* Select a segment in the real axis */
366:     PetscCall(RGComputeBoundingBox(nep->rg,&a,&b,NULL,NULL));
367:     PetscCheck(a>-PETSC_MAX_REAL && b<PETSC_MAX_REAL,PetscObjectComm((PetscObject)nep),PETSC_ERR_USER_INPUT,"NLEIGS requires a bounded target set");
368:     h = (b-a)/ndpt;
369:     for (i=0;i<ndpt;i++) {ds[i] = a+h*i; dsi[i] = 0.0;}
370:   }
371: #endif
372:   /* Discretize the singularity region */
373:   if (ctx->computesingularities) PetscCall(ctx->computesingularities(nep,&ndptx,dxi,ctx->singularitiesctx));
374:   else {
375:     if (nep->problem_type==NEP_RATIONAL) {
376:       PetscCall(NEPNLEIGSRationalSingularities(nep,&ndptx,dxi,&rational));
377:       PetscCheck(rational,PetscObjectComm((PetscObject)nep),PETSC_ERR_CONV_FAILED,"Failed to determine singularities automatically in rational problem; consider solving the problem as general");
378:     } else {
379:       /* AAA algorithm */
380:       PetscCall(NEPNLEIGSAAASingularities(nep,ndpt,ds,&ndptx,dxi));
381:     }
382:   }
383:   /* Look for Leja-Bagby points in the discretization sets */
384:   s[0]  = ds[0];
385:   xi[0] = (ndptx>0)?dxi[0]:PETSC_INFINITY;
386:   PetscCheck(PetscAbsScalar(xi[0])>=10*PETSC_MACHINE_EPSILON,PetscObjectComm((PetscObject)nep),PETSC_ERR_USER_INPUT,"Singularity point 0 is nearly zero: %g; consider removing the singularity or shifting the problem",(double)PetscAbsScalar(xi[0]));
387:   beta[0] = 1.0; /* scaling factors are also computed here */
388:   for (i=0;i<ndpt;i++) {
389:     nrs[i] = 1.0;
390:     nrxi[i] = 1.0;
391:   }
392:   for (k=1;k<ctx->ddmaxit;k++) {
393:     maxnrs = 0.0;
394:     minnrxi = PETSC_MAX_REAL;
395:     for (i=0;i<ndpt;i++) {
396:       nrs[i] *= ((ds[i]-s[k-1])/(1.0-ds[i]/xi[k-1]))/beta[k-1];
397:       if (PetscAbsScalar(nrs[i])>maxnrs) {maxnrs = PetscAbsScalar(nrs[i]); s[k] = ds[i];}
398:     }
399:     if (ndptx>k) {
400:       for (i=1;i<ndptx;i++) {
401:         nrxi[i] *= ((dxi[i]-s[k-1])/(1.0-dxi[i]/xi[k-1]))/beta[k-1];
402:         if (PetscAbsScalar(nrxi[i])<minnrxi) {minnrxi = PetscAbsScalar(nrxi[i]); xi[k] = dxi[i];}
403:       }
404:       PetscCheck(PetscAbsScalar(xi[k])>=10*PETSC_MACHINE_EPSILON,PetscObjectComm((PetscObject)nep),PETSC_ERR_USER_INPUT,"Singularity point %" PetscInt_FMT " is nearly zero: %g; consider removing the singularity or shifting the problem",k,(double)PetscAbsScalar(xi[k]));
405:     } else xi[k] = PETSC_INFINITY;
406:     beta[k] = maxnrs;
407:   }
408:   PetscCall(PetscFree5(ds,dsi,dxi,nrs,nrxi));
409:   PetscFunctionReturn(PETSC_SUCCESS);
410: }

412: PetscErrorCode NEPNLEIGSEvalNRTFunct(NEP nep,PetscInt k,PetscScalar sigma,PetscScalar *b)
413: {
414:   NEP_NLEIGS  *ctx=(NEP_NLEIGS*)nep->data;
415:   PetscInt    i;
416:   PetscScalar *beta=ctx->beta,*s=ctx->s,*xi=ctx->xi;

418:   PetscFunctionBegin;
419:   b[0] = 1.0/beta[0];
420:   for (i=0;i<k;i++) {
421:     b[i+1] = ((sigma-s[i])*b[i])/(beta[i+1]*(1.0-sigma/xi[i]));
422:   }
423:   PetscFunctionReturn(PETSC_SUCCESS);
424: }

426: static PetscErrorCode MatMult_Fun(Mat A,Vec x,Vec y)
427: {
428:   NEP_NLEIGS_MATSHELL *ctx;
429:   PetscInt            i;

431:   PetscFunctionBeginUser;
432:   PetscCall(MatShellGetContext(A,&ctx));
433:   PetscCall(MatMult(ctx->A[0],x,y));
434:   if (ctx->coeff[0]!=1.0) PetscCall(VecScale(y,ctx->coeff[0]));
435:   for (i=1;i<ctx->nmat;i++) {
436:     PetscCall(MatMult(ctx->A[i],x,ctx->t));
437:     PetscCall(VecAXPY(y,ctx->coeff[i],ctx->t));
438:   }
439:   PetscFunctionReturn(PETSC_SUCCESS);
440: }

442: static PetscErrorCode MatMultTranspose_Fun(Mat A,Vec x,Vec y)
443: {
444:   NEP_NLEIGS_MATSHELL *ctx;
445:   PetscInt            i;

447:   PetscFunctionBeginUser;
448:   PetscCall(MatShellGetContext(A,&ctx));
449:   PetscCall(MatMultTranspose(ctx->A[0],x,y));
450:   if (ctx->coeff[0]!=1.0) PetscCall(VecScale(y,ctx->coeff[0]));
451:   for (i=1;i<ctx->nmat;i++) {
452:     PetscCall(MatMultTranspose(ctx->A[i],x,ctx->t));
453:     PetscCall(VecAXPY(y,ctx->coeff[i],ctx->t));
454:   }
455:   PetscFunctionReturn(PETSC_SUCCESS);
456: }

458: static PetscErrorCode MatGetDiagonal_Fun(Mat A,Vec diag)
459: {
460:   NEP_NLEIGS_MATSHELL *ctx;
461:   PetscInt            i;

463:   PetscFunctionBeginUser;
464:   PetscCall(MatShellGetContext(A,&ctx));
465:   PetscCall(MatGetDiagonal(ctx->A[0],diag));
466:   if (ctx->coeff[0]!=1.0) PetscCall(VecScale(diag,ctx->coeff[0]));
467:   for (i=1;i<ctx->nmat;i++) {
468:     PetscCall(MatGetDiagonal(ctx->A[i],ctx->t));
469:     PetscCall(VecAXPY(diag,ctx->coeff[i],ctx->t));
470:   }
471:   PetscFunctionReturn(PETSC_SUCCESS);
472: }

474: static PetscErrorCode MatDuplicate_Fun(Mat A,MatDuplicateOption op,Mat *B)
475: {
476:   PetscInt            m,n,M,N,i;
477:   NEP_NLEIGS_MATSHELL *ctxnew,*ctx;
478:   PetscErrorCodeFn    *fun;

480:   PetscFunctionBeginUser;
481:   PetscCall(MatShellGetContext(A,&ctx));
482:   PetscCall(PetscNew(&ctxnew));
483:   ctxnew->nmat = ctx->nmat;
484:   ctxnew->maxnmat = ctx->maxnmat;
485:   PetscCall(PetscMalloc2(ctxnew->maxnmat,&ctxnew->A,ctxnew->maxnmat,&ctxnew->coeff));
486:   for (i=0;i<ctx->nmat;i++) {
487:     PetscCall(PetscObjectReference((PetscObject)ctx->A[i]));
488:     ctxnew->A[i] = ctx->A[i];
489:     ctxnew->coeff[i] = ctx->coeff[i];
490:   }
491:   PetscCall(MatGetSize(ctx->A[0],&M,&N));
492:   PetscCall(MatGetLocalSize(ctx->A[0],&m,&n));
493:   PetscCall(VecDuplicate(ctx->t,&ctxnew->t));
494:   PetscCall(MatCreateShell(PetscObjectComm((PetscObject)A),m,n,M,N,(void*)ctxnew,B));
495:   PetscCall(MatShellSetManageScalingShifts(*B));
496:   PetscCall(MatShellGetOperation(A,MATOP_MULT,&fun));
497:   PetscCall(MatShellSetOperation(*B,MATOP_MULT,fun));
498:   PetscCall(MatShellGetOperation(A,MATOP_MULT_TRANSPOSE,&fun));
499:   PetscCall(MatShellSetOperation(*B,MATOP_MULT_TRANSPOSE,fun));
500:   PetscCall(MatShellGetOperation(A,MATOP_GET_DIAGONAL,&fun));
501:   PetscCall(MatShellSetOperation(*B,MATOP_GET_DIAGONAL,fun));
502:   PetscCall(MatShellGetOperation(A,MATOP_DUPLICATE,&fun));
503:   PetscCall(MatShellSetOperation(*B,MATOP_DUPLICATE,fun));
504:   PetscCall(MatShellGetOperation(A,MATOP_DESTROY,&fun));
505:   PetscCall(MatShellSetOperation(*B,MATOP_DESTROY,fun));
506:   PetscCall(MatShellGetOperation(A,MATOP_AXPY,&fun));
507:   PetscCall(MatShellSetOperation(*B,MATOP_AXPY,fun));
508:   PetscFunctionReturn(PETSC_SUCCESS);
509: }

511: static PetscErrorCode MatDestroy_Fun(Mat A)
512: {
513:   NEP_NLEIGS_MATSHELL *ctx;
514:   PetscInt            i;

516:   PetscFunctionBeginUser;
517:   if (A) {
518:     PetscCall(MatShellGetContext(A,&ctx));
519:     for (i=0;i<ctx->nmat;i++) PetscCall(MatDestroy(&ctx->A[i]));
520:     PetscCall(VecDestroy(&ctx->t));
521:     PetscCall(PetscFree2(ctx->A,ctx->coeff));
522:     PetscCall(PetscFree(ctx));
523:   }
524:   PetscFunctionReturn(PETSC_SUCCESS);
525: }

527: static PetscErrorCode MatAXPY_Fun(Mat Y,PetscScalar a,Mat X,MatStructure str)
528: {
529:   NEP_NLEIGS_MATSHELL *ctxY,*ctxX;
530:   PetscInt            i,j;
531:   PetscBool           found,has;

533:   PetscFunctionBeginUser;
534:   PetscCall(MatShellGetContext(Y,&ctxY));
535:   PetscCall(MatShellGetContext(X,&ctxX));
536:   for (i=0;i<ctxX->nmat;i++) {
537:     found = PETSC_FALSE;
538:     for (j=0;!found&&j<ctxY->nmat;j++) {
539:       if (ctxX->A[i]==ctxY->A[j]) {
540:         found = PETSC_TRUE;
541:         ctxY->coeff[j] += a*ctxX->coeff[i];
542:       }
543:     }
544:     if (!found) {
545:       ctxY->coeff[ctxY->nmat] = a*ctxX->coeff[i];
546:       ctxY->A[ctxY->nmat] = ctxX->A[i];
547:       PetscCall(MatHasOperation(ctxX->A[i],MATOP_MULT_TRANSPOSE,&has));
548:       if (!has) PetscCall(MatShellSetOperation(ctxY->A[ctxY->nmat],MATOP_MULT_TRANSPOSE,NULL));
549:       PetscCall(MatHasOperation(ctxX->A[i],MATOP_GET_DIAGONAL,&has));
550:       if (!has) PetscCall(MatShellSetOperation(ctxY->A[ctxY->nmat],MATOP_GET_DIAGONAL,NULL));
551:       ctxY->nmat++;
552:       PetscCall(PetscObjectReference((PetscObject)ctxX->A[i]));
553:     }
554:   }
555:   PetscFunctionReturn(PETSC_SUCCESS);
556: }

558: static PetscErrorCode MatScale_Fun(Mat M,PetscScalar a)
559: {
560:   NEP_NLEIGS_MATSHELL *ctx;
561:   PetscInt            i;

563:   PetscFunctionBeginUser;
564:   PetscCall(MatShellGetContext(M,&ctx));
565:   for (i=0;i<ctx->nmat;i++) ctx->coeff[i] *= a;
566:   PetscFunctionReturn(PETSC_SUCCESS);
567: }

569: static PetscErrorCode NLEIGSMatToMatShellArray(Mat A,Mat *Ms,PetscInt maxnmat)
570: {
571:   NEP_NLEIGS_MATSHELL *ctx;
572:   PetscInt            m,n,M,N;
573:   PetscBool           has;

575:   PetscFunctionBegin;
576:   PetscCall(MatHasOperation(A,MATOP_DUPLICATE,&has));
577:   PetscCheck(has,PetscObjectComm((PetscObject)A),PETSC_ERR_USER,"MatDuplicate operation required");
578:   PetscCall(PetscNew(&ctx));
579:   ctx->maxnmat = maxnmat;
580:   PetscCall(PetscMalloc2(ctx->maxnmat,&ctx->A,ctx->maxnmat,&ctx->coeff));
581:   PetscCall(MatDuplicate(A,MAT_COPY_VALUES,&ctx->A[0]));
582:   ctx->nmat = 1;
583:   ctx->coeff[0] = 1.0;
584:   PetscCall(MatCreateVecs(A,&ctx->t,NULL));
585:   PetscCall(MatGetSize(A,&M,&N));
586:   PetscCall(MatGetLocalSize(A,&m,&n));
587:   PetscCall(MatCreateShell(PetscObjectComm((PetscObject)A),m,n,M,N,(void*)ctx,Ms));
588:   PetscCall(MatShellSetManageScalingShifts(*Ms));
589:   PetscCall(MatShellSetOperation(*Ms,MATOP_MULT,(PetscErrorCodeFn*)MatMult_Fun));
590:   PetscCall(MatHasOperation(A,MATOP_MULT_TRANSPOSE,&has));
591:   if (has) PetscCall(MatShellSetOperation(*Ms,MATOP_MULT_TRANSPOSE,(PetscErrorCodeFn*)MatMultTranspose_Fun));
592:   PetscCall(MatHasOperation(A,MATOP_GET_DIAGONAL,&has));
593:   if (has) PetscCall(MatShellSetOperation(*Ms,MATOP_GET_DIAGONAL,(PetscErrorCodeFn*)MatGetDiagonal_Fun));
594:   PetscCall(MatShellSetOperation(*Ms,MATOP_DUPLICATE,(PetscErrorCodeFn*)MatDuplicate_Fun));
595:   PetscCall(MatShellSetOperation(*Ms,MATOP_DESTROY,(PetscErrorCodeFn*)MatDestroy_Fun));
596:   PetscCall(MatShellSetOperation(*Ms,MATOP_AXPY,(PetscErrorCodeFn*)MatAXPY_Fun));
597:   PetscCall(MatShellSetOperation(*Ms,MATOP_SCALE,(PetscErrorCodeFn*)MatScale_Fun));
598:   PetscFunctionReturn(PETSC_SUCCESS);
599: }

601: /*
602:    MatIsShellAny - returns true if any of the n matrices is a shell matrix
603:  */
604: static PetscErrorCode MatIsShellAny(Mat *A,PetscInt n,PetscBool *shell)
605: {
606:   PetscInt       i;
607:   PetscBool      flg;

609:   PetscFunctionBegin;
610:   *shell = PETSC_FALSE;
611:   for (i=0;i<n;i++) {
612:     PetscCall(MatIsShell(A[i],&flg));
613:     if (flg) { *shell = PETSC_TRUE; break; }
614:   }
615:   PetscFunctionReturn(PETSC_SUCCESS);
616: }

618: static PetscErrorCode NEPNLEIGSDividedDifferences_split(NEP nep)
619: {
620:   PetscErrorCode ierr;
621:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
622:   PetscInt       k,j,i,maxnmat,nmax;
623:   PetscReal      norm0,norm,*matnorm;
624:   PetscScalar    *s=ctx->s,*beta=ctx->beta,*xi=ctx->xi,*b,alpha,*coeffs,*pK,*pH,sone=1.0;
625:   Mat            T,P,Ts,K,H;
626:   PetscBool      shell,hasmnorm=PETSC_FALSE,matrix=PETSC_TRUE;
627:   PetscBLASInt   n_;

629:   PetscFunctionBegin;
630:   nmax = ctx->ddmaxit;
631:   PetscCall(PetscMalloc1(nep->nt*nmax,&ctx->coeffD));
632:   PetscCall(PetscMalloc3(nmax+1,&b,nmax+1,&coeffs,nep->nt,&matnorm));
633:   for (j=0;j<nep->nt;j++) {
634:     PetscCall(MatHasOperation(nep->A[j],MATOP_NORM,&hasmnorm));
635:     if (!hasmnorm) break;
636:     PetscCall(MatNorm(nep->A[j],NORM_INFINITY,matnorm+j));
637:   }
638:   /* Try matrix functions scheme */
639:   PetscCall(PetscCalloc2(nmax*nmax,&pK,nmax*nmax,&pH));
640:   for (i=0;i<nmax-1;i++) {
641:     pK[(nmax+1)*i]   = 1.0;
642:     pK[(nmax+1)*i+1] = beta[i+1]/xi[i];
643:     pH[(nmax+1)*i]   = s[i];
644:     pH[(nmax+1)*i+1] = beta[i+1];
645:   }
646:   pH[nmax*nmax-1] = s[nmax-1];
647:   pK[nmax*nmax-1] = 1.0;
648:   PetscCall(PetscBLASIntCast(nmax,&n_));
649:   PetscCallBLAS("BLAStrsm",BLAStrsm_("R","L","N","U",&n_,&n_,&sone,pK,&n_,pH,&n_));
650:   /* The matrix to be used is in H. K will be a work-space matrix */
651:   PetscCall(MatCreateSeqDense(PETSC_COMM_SELF,nmax,nmax,pH,&H));
652:   PetscCall(MatCreateSeqDense(PETSC_COMM_SELF,nmax,nmax,pK,&K));
653:   for (j=0;matrix&&j<nep->nt;j++) {
654:     PetscCall(PetscPushErrorHandler(PetscReturnErrorHandler,NULL));
655:     ierr = FNEvaluateFunctionMat(nep->f[j],H,K);
656:     PetscCall(PetscPopErrorHandler());
657:     if (!ierr) {
658:       for (i=0;i<nmax;i++) ctx->coeffD[j+i*nep->nt] = pK[i]*beta[0];
659:     } else {
660:       matrix = PETSC_FALSE;
661:       PetscCall(PetscFPTrapPop());
662:     }
663:   }
664:   PetscCall(MatDestroy(&H));
665:   PetscCall(MatDestroy(&K));
666:   if (!matrix) {
667:     for (j=0;j<nep->nt;j++) {
668:       PetscCall(FNEvaluateFunction(nep->f[j],s[0],ctx->coeffD+j));
669:       ctx->coeffD[j] *= beta[0];
670:     }
671:   }
672:   if (hasmnorm) {
673:     norm0 = 0.0;
674:     for (j=0;j<nep->nt;j++) norm0 += matnorm[j]*PetscAbsScalar(ctx->coeffD[j]);
675:   } else {
676:     norm0 = 0.0;
677:     for (j=0;j<nep->nt;j++) norm0 = PetscMax(PetscAbsScalar(ctx->coeffD[j]),norm0);
678:   }
679:   ctx->nmat = ctx->ddmaxit;
680:   for (k=1;k<ctx->ddmaxit;k++) {
681:     if (!matrix) {
682:       PetscCall(NEPNLEIGSEvalNRTFunct(nep,k,s[k],b));
683:       for (i=0;i<nep->nt;i++) {
684:         PetscCall(FNEvaluateFunction(nep->f[i],s[k],ctx->coeffD+k*nep->nt+i));
685:         for (j=0;j<k;j++) {
686:           ctx->coeffD[k*nep->nt+i] -= b[j]*ctx->coeffD[i+nep->nt*j];
687:         }
688:         ctx->coeffD[k*nep->nt+i] /= b[k];
689:       }
690:     }
691:     if (hasmnorm) {
692:       norm = 0.0;
693:       for (j=0;j<nep->nt;j++) norm += matnorm[j]*PetscAbsScalar(ctx->coeffD[k*nep->nt+j]);
694:     } else {
695:       norm = 0.0;
696:       for (j=0;j<nep->nt;j++) norm = PetscMax(PetscAbsScalar(ctx->coeffD[k*nep->nt+j]),norm);
697:     }
698:     if (k>1 && norm/norm0 < ctx->ddtol) {
699:       ctx->nmat = k+1;
700:       break;
701:     }
702:   }
703:   if (!ctx->ksp) PetscCall(NEPNLEIGSGetKSPs(nep,&ctx->nshiftsw,&ctx->ksp));
704:   PetscCall(MatIsShellAny(nep->A,nep->nt,&shell));
705:   maxnmat = PetscMax(ctx->ddmaxit,nep->nt);
706:   for (i=0;i<ctx->nshiftsw;i++) {
707:     PetscCall(NEPNLEIGSEvalNRTFunct(nep,ctx->nmat-1,ctx->shifts[i],coeffs));
708:     if (!shell) PetscCall(MatDuplicate(nep->A[0],MAT_COPY_VALUES,&T));
709:     else PetscCall(NLEIGSMatToMatShellArray(nep->A[0],&T,maxnmat));
710:     if (nep->P) { /* user-defined preconditioner */
711:       PetscCall(MatDuplicate(nep->P[0],MAT_COPY_VALUES,&P));
712:     } else P=T;
713:     alpha = 0.0;
714:     for (j=0;j<ctx->nmat;j++) alpha += coeffs[j]*ctx->coeffD[j*nep->nt];
715:     PetscCall(MatScale(T,alpha));
716:     if (nep->P) PetscCall(MatScale(P,alpha));
717:     for (k=1;k<nep->nt;k++) {
718:       alpha = 0.0;
719:       for (j=0;j<ctx->nmat;j++) alpha += coeffs[j]*ctx->coeffD[j*nep->nt+k];
720:       if (shell) PetscCall(NLEIGSMatToMatShellArray(nep->A[k],&Ts,maxnmat));
721:       PetscCall(MatAXPY(T,alpha,shell?Ts:nep->A[k],nep->mstr));
722:       if (nep->P) PetscCall(MatAXPY(P,alpha,nep->P[k],nep->mstrp));
723:       if (shell) PetscCall(MatDestroy(&Ts));
724:     }
725:     PetscCall(NEP_KSPSetOperators(ctx->ksp[i],T,P));
726:     PetscCall(KSPSetUp(ctx->ksp[i]));
727:     PetscCall(MatDestroy(&T));
728:     if (nep->P) PetscCall(MatDestroy(&P));
729:   }
730:   PetscCall(PetscFree3(b,coeffs,matnorm));
731:   PetscCall(PetscFree2(pK,pH));
732:   PetscFunctionReturn(PETSC_SUCCESS);
733: }

735: static PetscErrorCode NEPNLEIGSDividedDifferences_callback(NEP nep)
736: {
737:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
738:   PetscInt       k,j,i,maxnmat;
739:   PetscReal      norm0,norm;
740:   PetscScalar    *s=ctx->s,*beta=ctx->beta,*b,*coeffs;
741:   Mat            *D=ctx->D,*DP,T,P;
742:   PetscBool      shell,has,precond=(nep->function_pre!=nep->function)?PETSC_TRUE:PETSC_FALSE;
743:   PetscRandom    rand=NULL;

745:   PetscFunctionBegin;
746:   PetscCall(PetscMalloc2(ctx->ddmaxit+1,&b,ctx->ddmaxit+1,&coeffs));
747:   if (nep->V) PetscCall(BVGetRandomContext(nep->V,&rand));
748:   T = nep->function;
749:   P = nep->function_pre;
750:   PetscCall(NEPComputeFunction(nep,s[0],T,P));
751:   PetscCall(MatIsShell(T,&shell));
752:   maxnmat = PetscMax(ctx->ddmaxit,nep->nt);
753:   if (!shell) PetscCall(MatDuplicate(T,MAT_COPY_VALUES,&D[0]));
754:   else PetscCall(NLEIGSMatToMatShellArray(T,&D[0],maxnmat));
755:   if (beta[0]!=1.0) PetscCall(MatScale(D[0],1.0/beta[0]));
756:   PetscCall(MatHasOperation(D[0],MATOP_NORM,&has));
757:   if (has) PetscCall(MatNorm(D[0],NORM_FROBENIUS,&norm0));
758:   else PetscCall(MatNormApproximate(D[0],NORM_2,1,&norm0));
759:   if (precond) {
760:     PetscCall(PetscMalloc1(ctx->ddmaxit,&DP));
761:     PetscCall(MatDuplicate(P,MAT_COPY_VALUES,&DP[0]));
762:   }
763:   ctx->nmat = ctx->ddmaxit;
764:   for (k=1;k<ctx->ddmaxit;k++) {
765:     PetscCall(NEPNLEIGSEvalNRTFunct(nep,k,s[k],b));
766:     PetscCall(NEPComputeFunction(nep,s[k],T,P));
767:     if (!shell) PetscCall(MatDuplicate(T,MAT_COPY_VALUES,&D[k]));
768:     else PetscCall(NLEIGSMatToMatShellArray(T,&D[k],maxnmat));
769:     for (j=0;j<k;j++) PetscCall(MatAXPY(D[k],-b[j],D[j],nep->mstr));
770:     PetscCall(MatScale(D[k],1.0/b[k]));
771:     PetscCall(MatHasOperation(D[k],MATOP_NORM,&has));
772:     if (has) PetscCall(MatNorm(D[k],NORM_FROBENIUS,&norm));
773:     else PetscCall(MatNormApproximate(D[k],NORM_2,1,&norm));
774:     if (precond) {
775:       PetscCall(MatDuplicate(P,MAT_COPY_VALUES,&DP[k]));
776:       for (j=0;j<k;j++) PetscCall(MatAXPY(DP[k],-b[j],DP[j],nep->mstrp));
777:       PetscCall(MatScale(DP[k],1.0/b[k]));
778:     }
779:     if (k>1 && norm/norm0 < ctx->ddtol && k>1) {
780:       ctx->nmat = k+1;
781:       break;
782:     }
783:   }
784:   if (!ctx->ksp) PetscCall(NEPNLEIGSGetKSPs(nep,&ctx->nshiftsw,&ctx->ksp));
785:   for (i=0;i<ctx->nshiftsw;i++) {
786:     PetscCall(NEPNLEIGSEvalNRTFunct(nep,ctx->nmat-1,ctx->shifts[i],coeffs));
787:     PetscCall(MatDuplicate(D[0],MAT_COPY_VALUES,&T));
788:     if (coeffs[0]!=1.0) PetscCall(MatScale(T,coeffs[0]));
789:     for (j=1;j<ctx->nmat;j++) PetscCall(MatAXPY(T,coeffs[j],D[j],nep->mstr));
790:     if (precond) {
791:       PetscCall(MatDuplicate(DP[0],MAT_COPY_VALUES,&P));
792:       if (coeffs[0]!=1.0) PetscCall(MatScale(P,coeffs[0]));
793:       for (j=1;j<ctx->nmat;j++) PetscCall(MatAXPY(P,coeffs[j],DP[j],nep->mstrp));
794:     } else P=T;
795:     PetscCall(NEP_KSPSetOperators(ctx->ksp[i],T,P));
796:     PetscCall(KSPSetUp(ctx->ksp[i]));
797:     PetscCall(MatDestroy(&T));
798:   }
799:   PetscCall(PetscFree2(b,coeffs));
800:   if (precond) {
801:     PetscCall(MatDestroy(&P));
802:     PetscCall(MatDestroyMatrices(ctx->nmat,&DP));
803:   }
804:   PetscFunctionReturn(PETSC_SUCCESS);
805: }

807: /*
808:    NEPKrylovConvergence - This is the analogue to EPSKrylovConvergence.
809: */
810: static PetscErrorCode NEPNLEIGSKrylovConvergence(NEP nep,PetscBool getall,PetscInt kini,PetscInt nits,PetscReal betah,PetscScalar betak,PetscInt *kout,Vec *w)
811: {
812:   PetscInt       k,newk,marker,inside;
813:   PetscScalar    re,im;
814:   PetscReal      resnorm,tt;
815:   PetscBool      istrivial;
816:   NEP_NLEIGS     *ctx = (NEP_NLEIGS*)nep->data;

818:   PetscFunctionBegin;
819:   PetscCall(RGIsTrivial(nep->rg,&istrivial));
820:   marker = -1;
821:   if (nep->trackall) getall = PETSC_TRUE;
822:   for (k=kini;k<kini+nits;k++) {
823:     /* eigenvalue */
824:     re = nep->eigr[k];
825:     im = nep->eigi[k];
826:     if (!istrivial) {
827:       if (!ctx->nshifts) PetscCall(NEPNLEIGSBackTransform((PetscObject)nep,1,&re,&im));
828:       PetscCall(RGCheckInside(nep->rg,1,&re,&im,&inside));
829:       if (marker==-1 && inside<0) marker = k;
830:     }
831:     newk = k;
832:     PetscCall(DSVectors(nep->ds,DS_MAT_X,&newk,&resnorm));
833:     tt = ctx->nshifts?SlepcAbsEigenvalue(betak-nep->eigr[k]*betah,nep->eigi[k]*betah):betah;
834:     resnorm *=  PetscAbsReal(tt);
835:     /* error estimate */
836:     PetscCall((*nep->converged)(nep,nep->eigr[k],nep->eigi[k],resnorm,&nep->errest[k],nep->convergedctx));
837:     if (marker==-1 && nep->errest[k] >= nep->tol) marker = k;
838:     if (newk==k+1) {
839:       nep->errest[k+1] = nep->errest[k];
840:       k++;
841:     }
842:     if (marker!=-1 && !getall) break;
843:   }
844:   if (marker!=-1) k = marker;
845:   *kout = k;
846:   PetscFunctionReturn(PETSC_SUCCESS);
847: }

849: static PetscErrorCode NEPSetUp_NLEIGS(NEP nep)
850: {
851:   PetscInt       k,in;
852:   PetscScalar    zero=0.0;
853:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
854:   SlepcSC        sc;
855:   PetscBool      istrivial;

857:   PetscFunctionBegin;
858:   PetscCall(NEPSetDimensions_Default(nep,nep->nev,&nep->ncv,&nep->mpd));
859:   PetscCheck(nep->ncv<=nep->nev+nep->mpd,PetscObjectComm((PetscObject)nep),PETSC_ERR_USER_INPUT,"The value of ncv must not be larger than nev+mpd");
860:   if (nep->max_it==PETSC_DETERMINE) nep->max_it = PetscMax(5000,2*nep->n/nep->ncv);
861:   if (!ctx->ddmaxit) ctx->ddmaxit = LBPOINTS;
862:   PetscCall(RGIsTrivial(nep->rg,&istrivial));
863:   PetscCheck(!istrivial,PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"NEPNLEIGS requires a nontrivial region defining the target set");
864:   if (!nep->which) nep->which = NEP_TARGET_MAGNITUDE;
865:   PetscCheck(nep->which==NEP_TARGET_MAGNITUDE || nep->which==NEP_TARGET_REAL || nep->which==NEP_TARGET_IMAGINARY || nep->which==NEP_WHICH_USER,PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"This solver supports only target selection of eigenvalues");

867:   /* Initialize the NLEIGS context structure */
868:   k = ctx->ddmaxit;
869:   PetscCall(PetscMalloc4(k,&ctx->s,k,&ctx->xi,k,&ctx->beta,k,&ctx->D));
870:   nep->data = ctx;
871:   if (nep->tol==(PetscReal)PETSC_DETERMINE) nep->tol = SLEPC_DEFAULT_TOL;
872:   if (ctx->ddtol==(PetscReal)PETSC_DETERMINE) ctx->ddtol = nep->tol/10.0;
873:   if (!ctx->keep) ctx->keep = 0.5;

875:   /* Compute Leja-Bagby points and scaling values */
876:   PetscCall(NEPNLEIGSLejaBagbyPoints(nep));
877:   if (nep->problem_type!=NEP_RATIONAL) {
878:     PetscCall(RGCheckInside(nep->rg,1,&nep->target,&zero,&in));
879:     PetscCheck(in>=0,PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"The target is not inside the target set");
880:   }

882:   /* Compute the divided difference matrices */
883:   if (nep->fui==NEP_USER_INTERFACE_SPLIT) PetscCall(NEPNLEIGSDividedDifferences_split(nep));
884:   else PetscCall(NEPNLEIGSDividedDifferences_callback(nep));
885:   PetscCall(NEPAllocateSolution(nep,ctx->nmat-1));
886:   PetscCall(NEPSetWorkVecs(nep,4));
887:   if (!ctx->fullbasis) {
888:     PetscCheck(!nep->twosided,PetscObjectComm((PetscObject)nep),PETSC_ERR_SUP,"Two-sided variant requires the full-basis option, rerun with -nep_nleigs_full_basis");
889:     /* set-up DS and transfer split operator functions */
890:     PetscCall(DSSetType(nep->ds,ctx->nshifts?DSGNHEP:DSNHEP));
891:     PetscCall(DSAllocate(nep->ds,nep->ncv+1));
892:     PetscCall(DSGetSlepcSC(nep->ds,&sc));
893:     if (!ctx->nshifts) sc->map = NEPNLEIGSBackTransform;
894:     PetscCall(DSSetExtraRow(nep->ds,PETSC_TRUE));
895:     sc->mapobj        = (PetscObject)nep;
896:     sc->rg            = nep->rg;
897:     sc->comparison    = nep->sc->comparison;
898:     sc->comparisonctx = nep->sc->comparisonctx;
899:     PetscCall(BVDestroy(&ctx->V));
900:     PetscCall(BVCreateTensor(nep->V,ctx->nmat-1,&ctx->V));
901:     nep->ops->solve          = NEPSolve_NLEIGS;
902:     nep->ops->computevectors = NEPComputeVectors_Schur;
903:   } else {
904:     PetscCall(NEPSetUp_NLEIGS_FullBasis(nep));
905:     nep->ops->solve          = NEPSolve_NLEIGS_FullBasis;
906:     nep->ops->computevectors = NULL;
907:   }
908:   PetscFunctionReturn(PETSC_SUCCESS);
909: }

911: /*
912:   Extend the TOAR basis by applying the matrix operator
913:   over a vector which is decomposed on the TOAR way
914:   Input:
915:     - S,V: define the latest Arnoldi vector (nv vectors in V)
916:   Output:
917:     - t: new vector extending the TOAR basis
918:     - r: temporally coefficients to compute the TOAR coefficients
919:          for the new Arnoldi vector
920:   Workspace: t_ (two vectors)
921: */
922: static PetscErrorCode NEPTOARExtendBasis(NEP nep,PetscInt idxrktg,PetscScalar *S,PetscInt ls,PetscInt nv,BV W,BV V,Vec t,PetscScalar *r,PetscInt lr,Vec *t_)
923: {
924:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
925:   PetscInt       deg=ctx->nmat-1,k,j;
926:   Vec            v=t_[0],q=t_[1],w;
927:   PetscScalar    *beta=ctx->beta,*s=ctx->s,*xi=ctx->xi,*coeffs,sigma;

929:   PetscFunctionBegin;
930:   if (!ctx->ksp) PetscCall(NEPNLEIGSGetKSPs(nep,&ctx->nshiftsw,&ctx->ksp));
931:   sigma = ctx->shifts[idxrktg];
932:   PetscCall(BVSetActiveColumns(nep->V,0,nv));
933:   PetscCall(PetscMalloc1(ctx->nmat,&coeffs));
934:   PetscCheck(PetscAbsScalar(s[deg-2]-sigma)>100*PETSC_MACHINE_EPSILON,PETSC_COMM_SELF,PETSC_ERR_CONV_FAILED,"Breakdown in NLEIGS");
935:   /* i-part stored in (i-1) position */
936:   for (j=0;j<nv;j++) {
937:     r[(deg-2)*lr+j] = (S[(deg-2)*ls+j]+(beta[deg-1]/xi[deg-2])*S[(deg-1)*ls+j])/(s[deg-2]-sigma);
938:   }
939:   PetscCall(BVSetActiveColumns(W,0,deg));
940:   PetscCall(BVGetColumn(W,deg-1,&w));
941:   PetscCall(BVMultVec(V,1.0/beta[deg],0,w,S+(deg-1)*ls));
942:   PetscCall(BVRestoreColumn(W,deg-1,&w));
943:   PetscCall(BVGetColumn(W,deg-2,&w));
944:   PetscCall(BVMultVec(V,1.0,0.0,w,r+(deg-2)*lr));
945:   PetscCall(BVRestoreColumn(W,deg-2,&w));
946:   for (k=deg-2;k>0;k--) {
947:     PetscCheck(PetscAbsScalar(s[k-1]-sigma)>100*PETSC_MACHINE_EPSILON,PETSC_COMM_SELF,PETSC_ERR_CONV_FAILED,"Breakdown in NLEIGS");
948:     for (j=0;j<nv;j++) r[(k-1)*lr+j] = (S[(k-1)*ls+j]+(beta[k]/xi[k-1])*S[k*ls+j]-beta[k]*(1.0-sigma/xi[k-1])*r[k*lr+j])/(s[k-1]-sigma);
949:     PetscCall(BVGetColumn(W,k-1,&w));
950:     PetscCall(BVMultVec(V,1.0,0.0,w,r+(k-1)*lr));
951:     PetscCall(BVRestoreColumn(W,k-1,&w));
952:   }
953:   if (nep->fui==NEP_USER_INTERFACE_SPLIT) {
954:     for (j=0;j<ctx->nmat-2;j++) coeffs[j] = ctx->coeffD[nep->nt*j];
955:     coeffs[ctx->nmat-2] = ctx->coeffD[nep->nt*(ctx->nmat-1)];
956:     PetscCall(BVMultVec(W,1.0,0.0,v,coeffs));
957:     PetscCall(MatMult(nep->A[0],v,q));
958:     for (k=1;k<nep->nt;k++) {
959:       for (j=0;j<ctx->nmat-2;j++) coeffs[j] = ctx->coeffD[nep->nt*j+k];
960:       coeffs[ctx->nmat-2] = ctx->coeffD[nep->nt*(ctx->nmat-1)+k];
961:       PetscCall(BVMultVec(W,1.0,0,v,coeffs));
962:       PetscCall(MatMult(nep->A[k],v,t));
963:       PetscCall(VecAXPY(q,1.0,t));
964:     }
965:     PetscCall(KSPSolve(ctx->ksp[idxrktg],q,t));
966:     PetscCall(VecScale(t,-1.0));
967:   } else {
968:     for (k=0;k<deg-1;k++) {
969:       PetscCall(BVGetColumn(W,k,&w));
970:       PetscCall(MatMult(ctx->D[k],w,q));
971:       PetscCall(BVRestoreColumn(W,k,&w));
972:       PetscCall(BVInsertVec(W,k,q));
973:     }
974:     PetscCall(BVGetColumn(W,deg-1,&w));
975:     PetscCall(MatMult(ctx->D[deg],w,q));
976:     PetscCall(BVRestoreColumn(W,k,&w));
977:     PetscCall(BVInsertVec(W,k,q));
978:     for (j=0;j<ctx->nmat-1;j++) coeffs[j] = 1.0;
979:     PetscCall(BVMultVec(W,1.0,0.0,q,coeffs));
980:     PetscCall(KSPSolve(ctx->ksp[idxrktg],q,t));
981:     PetscCall(VecScale(t,-1.0));
982:   }
983:   PetscCall(PetscFree(coeffs));
984:   PetscFunctionReturn(PETSC_SUCCESS);
985: }

987: /*
988:   Compute TOAR coefficients of the blocks of the new Arnoldi vector computed
989: */
990: static PetscErrorCode NEPTOARCoefficients(NEP nep,PetscScalar sigma,PetscInt nv,PetscScalar *S,PetscInt ls,PetscScalar *r,PetscInt lr,PetscScalar *x,PetscScalar *work)
991: {
992:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
993:   PetscInt       k,j,d=ctx->nmat-1;
994:   PetscScalar    *t=work;

996:   PetscFunctionBegin;
997:   PetscCall(NEPNLEIGSEvalNRTFunct(nep,d-1,sigma,t));
998:   for (k=0;k<d-1;k++) {
999:     for (j=0;j<=nv;j++) r[k*lr+j] += t[k]*x[j];
1000:   }
1001:   for (j=0;j<=nv;j++) r[(d-1)*lr+j] = t[d-1]*x[j];
1002:   PetscFunctionReturn(PETSC_SUCCESS);
1003: }

1005: /*
1006:   Compute continuation vector coefficients for the Rational-Krylov run.
1007:   dim(work) >= (end-ini)*(end-ini+1) + end+1 + 2*(end-ini+1), dim(t) = end.
1008: */
1009: static PetscErrorCode NEPNLEIGS_RKcontinuation(NEP nep,PetscInt ini,PetscInt end,PetscScalar *K,PetscScalar *H,PetscInt ld,PetscScalar sigma,PetscScalar *S,PetscInt lds,PetscScalar *cont,PetscScalar *t,PetscScalar *work)
1010: {
1011:   PetscScalar    *x,*W,*tau,sone=1.0,szero=0.0;
1012:   PetscInt       i,j,n1,n,nwu=0;
1013:   PetscBLASInt   n_,n1_,one=1,dim,lds_;
1014:   NEP_NLEIGS     *ctx = (NEP_NLEIGS*)nep->data;

1016:   PetscFunctionBegin;
1017:   if (!ctx->nshifts || !end) {
1018:     t[0] = 1;
1019:     PetscCall(PetscArraycpy(cont,S+end*lds,lds));
1020:   } else {
1021:     n   = end-ini;
1022:     n1  = n+1;
1023:     x   = work+nwu;
1024:     nwu += end+1;
1025:     tau = work+nwu;
1026:     nwu += n;
1027:     W   = work+nwu;
1028:     nwu += n1*n;
1029:     for (j=ini;j<end;j++) {
1030:       for (i=ini;i<=end;i++) W[(j-ini)*n1+i-ini] = K[j*ld+i] -H[j*ld+i]*sigma;
1031:     }
1032:     PetscCall(PetscBLASIntCast(n,&n_));
1033:     PetscCall(PetscBLASIntCast(n1,&n1_));
1034:     PetscCall(PetscBLASIntCast(end+1,&dim));
1035:     PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
1036:     PetscCallLAPACKInfo("LAPACKgeqrf",LAPACKgeqrf_(&n1_,&n_,W,&n1_,tau,work+nwu,&n1_,&info));
1037:     for (i=0;i<end;i++) t[i] = 0.0;
1038:     t[end] = 1.0;
1039:     for (j=n-1;j>=0;j--) {
1040:       for (i=0;i<ini+j;i++) x[i] = 0.0;
1041:       x[ini+j] = 1.0;
1042:       for (i=j+1;i<n1;i++) x[i+ini] = W[i+n1*j];
1043:       tau[j] = PetscConj(tau[j]);
1044:       PetscCallBLAS("LAPACKlarf",LAPACKlarf_("L",&dim,&one,x,&one,tau+j,t,&dim,work+nwu));
1045:     }
1046:     PetscCall(PetscBLASIntCast(lds,&lds_));
1047:     PetscCallBLAS("BLASgemv",BLASgemv_("N",&lds_,&n1_,&sone,S,&lds_,t,&one,&szero,cont,&one));
1048:     PetscCall(PetscFPTrapPop());
1049:   }
1050:   PetscFunctionReturn(PETSC_SUCCESS);
1051: }

1053: /*
1054:   Compute a run of Arnoldi iterations
1055: */
1056: static PetscErrorCode NEPNLEIGSTOARrun(NEP nep,Mat MK,Mat MH,BV W,PetscInt k,PetscInt *M,PetscReal *betah,PetscScalar *betak,PetscBool *breakdown,Vec *t_)
1057: {
1058:   NEP_NLEIGS     *ctx = (NEP_NLEIGS*)nep->data;
1059:   PetscInt       i,j,m=*M,lwa,deg=ctx->nmat-1,lds,nqt,ld,l,ldh;
1060:   Vec            t;
1061:   PetscReal      norm=0.0;
1062:   PetscScalar    *x,*work,*tt,sigma=1.0,*cont,*S,*K=NULL,*H;
1063:   PetscBool      lindep;
1064:   Mat            MS;

1066:   PetscFunctionBegin;
1067:   *betah = 0.0; *betak = 0.0;
1068:   PetscCall(MatDenseGetArray(MH,&H));
1069:   if (MK) PetscCall(MatDenseGetArray(MK,&K));
1070:   PetscCall(MatDenseGetLDA(MH,&ldh));
1071:   PetscCall(BVTensorGetFactors(ctx->V,NULL,&MS));
1072:   PetscCall(MatDenseGetArray(MS,&S));
1073:   PetscCall(BVGetSizes(nep->V,NULL,NULL,&ld));
1074:   lds = ld*deg;
1075:   PetscCall(BVGetActiveColumns(nep->V,&l,&nqt));
1076:   lwa = PetscMax(ld,deg)+(m+1)*(m+1)+4*(m+1);
1077:   PetscCall(PetscMalloc4(ld,&x,lwa,&work,m+1,&tt,lds,&cont));
1078:   PetscCall(BVSetActiveColumns(ctx->V,0,m));
1079:   for (j=k;j<m;j++) {
1080:     sigma = ctx->shifts[(++ctx->idxrk)%ctx->nshiftsw];

1082:     /* Continuation vector */
1083:     PetscCall(NEPNLEIGS_RKcontinuation(nep,0,j,K,H,ldh,sigma,S,lds,cont,tt,work));

1085:     /* apply operator */
1086:     PetscCall(BVGetColumn(nep->V,nqt,&t));
1087:     PetscCall(NEPTOARExtendBasis(nep,(ctx->idxrk)%ctx->nshiftsw,cont,ld,nqt,W,nep->V,t,S+(j+1)*lds,ld,t_));
1088:     PetscCall(BVRestoreColumn(nep->V,nqt,&t));

1090:     /* orthogonalize */
1091:     PetscCall(BVOrthogonalizeColumn(nep->V,nqt,x,&norm,&lindep));
1092:     if (!lindep) {
1093:       x[nqt] = norm;
1094:       PetscCall(BVScaleColumn(nep->V,nqt,1.0/norm));
1095:       nqt++;
1096:     } else x[nqt] = 0.0;

1098:     PetscCall(NEPTOARCoefficients(nep,sigma,nqt-1,cont,ld,S+(j+1)*lds,ld,x,work));

1100:     /* Level-2 orthogonalization */
1101:     PetscCall(BVOrthogonalizeColumn(ctx->V,j+1,H+j*ldh,&norm,breakdown));
1102:     H[j+1+ldh*j] = norm;
1103:     if (ctx->nshifts && MK) {
1104:       for (i=0;i<=j;i++) K[i+ldh*j] = sigma*H[i+ldh*j] + tt[i];
1105:       K[j+1+ldh*j] = sigma*H[j+1+ldh*j];
1106:     }
1107:     if (*breakdown) {
1108:       *M = j+1;
1109:       break;
1110:     }
1111:     PetscCall(BVScaleColumn(ctx->V,j+1,1.0/norm));
1112:     PetscCall(BVSetActiveColumns(nep->V,l,nqt));
1113:   }
1114:   *betah = norm;
1115:   if (ctx->nshifts) *betak = norm*sigma;
1116:   PetscCall(PetscFree4(x,work,tt,cont));
1117:   PetscCall(MatDenseRestoreArray(MS,&S));
1118:   PetscCall(MatDenseRestoreArray(MH,&H));
1119:   if (MK) PetscCall(MatDenseRestoreArray(MK,&K));
1120:   PetscCall(BVTensorRestoreFactors(ctx->V,NULL,&MS));
1121:   PetscFunctionReturn(PETSC_SUCCESS);
1122: }

1124: PetscErrorCode NEPSolve_NLEIGS(NEP nep)
1125: {
1126:   NEP_NLEIGS        *ctx = (NEP_NLEIGS*)nep->data;
1127:   PetscInt          i,k=0,l,nv=0,ld,lds,nq;
1128:   PetscInt          deg=ctx->nmat-1,nconv=0,dsn,dsk;
1129:   PetscScalar       *pU,betak=0,*eigr,*eigi;
1130:   const PetscScalar *S;
1131:   PetscReal         betah;
1132:   PetscBool         falselock=PETSC_FALSE,breakdown=PETSC_FALSE;
1133:   BV                W;
1134:   Mat               H,K=NULL,MS,MQ,U;

1136:   PetscFunctionBegin;
1137:   if (ctx->lock) {
1138:     /* undocumented option to use a cheaper locking instead of the true locking */
1139:     PetscCall(PetscOptionsGetBool(NULL,NULL,"-nep_nleigs_falselocking",&falselock,NULL));
1140:   }

1142:   PetscCall(BVGetSizes(nep->V,NULL,NULL,&ld));
1143:   lds = deg*ld;
1144:   if (!ctx->nshifts) PetscCall(PetscMalloc2(nep->ncv,&eigr,nep->ncv,&eigi));
1145:   else { eigr = nep->eigr; eigi = nep->eigi; }
1146:   PetscCall(BVDuplicateResize(nep->V,PetscMax(nep->nt-1,ctx->nmat-1),&W));

1148:   /* clean projected matrix (including the extra-arrow) */
1149:   PetscCall(DSSetDimensions(nep->ds,PETSC_DETERMINE,PETSC_DETERMINE,PETSC_DETERMINE));
1150:   PetscCall(DSGetMat(nep->ds,DS_MAT_A,&H));
1151:   PetscCall(MatZeroEntries(H));
1152:   PetscCall(DSRestoreMat(nep->ds,DS_MAT_A,&H));
1153:   if (ctx->nshifts) {
1154:     PetscCall(DSGetMat(nep->ds,DS_MAT_B,&H));
1155:     PetscCall(MatZeroEntries(H));
1156:     PetscCall(DSRestoreMat(nep->ds,DS_MAT_B,&H));
1157:   }

1159:   /* Get the starting Arnoldi vector */
1160:   PetscCall(BVTensorBuildFirstColumn(ctx->V,nep->nini));

1162:   /* Restart loop */
1163:   l = 0;
1164:   while (nep->reason == NEP_CONVERGED_ITERATING) {
1165:     nep->its++;

1167:     /* Compute an nv-step Krylov relation */
1168:     nv = PetscMin(nep->nconv+nep->mpd,nep->ncv);
1169:     if (ctx->nshifts) PetscCall(DSGetMat(nep->ds,DS_MAT_A,&K));
1170:     PetscCall(DSGetMat(nep->ds,ctx->nshifts?DS_MAT_B:DS_MAT_A,&H));
1171:     PetscCall(NEPNLEIGSTOARrun(nep,K,H,W,nep->nconv+l,&nv,&betah,&betak,&breakdown,nep->work));
1172:     PetscCall(DSRestoreMat(nep->ds,ctx->nshifts?DS_MAT_B:DS_MAT_A,&H));
1173:     if (ctx->nshifts) PetscCall(DSRestoreMat(nep->ds,DS_MAT_A,&K));
1174:     PetscCall(DSSetDimensions(nep->ds,nv,nep->nconv,nep->nconv+l));
1175:     if (l==0) PetscCall(DSSetState(nep->ds,DS_STATE_INTERMEDIATE));
1176:     else PetscCall(DSSetState(nep->ds,DS_STATE_RAW));

1178:     /* Solve projected problem */
1179:     PetscCall(DSSolve(nep->ds,nep->eigr,nep->eigi));
1180:     PetscCall(DSSort(nep->ds,nep->eigr,nep->eigi,NULL,NULL,NULL));
1181:     PetscCall(DSUpdateExtraRow(nep->ds));
1182:     PetscCall(DSSynchronize(nep->ds,nep->eigr,nep->eigi));

1184:     /* Check convergence */
1185:     PetscCall(NEPNLEIGSKrylovConvergence(nep,PETSC_FALSE,nep->nconv,nv-nep->nconv,betah,betak,&k,nep->work));
1186:     PetscCall((*nep->stopping)(nep,nep->its,nep->max_it,k,nep->nev,&nep->reason,nep->stoppingctx));

1188:     /* Update l */
1189:     if (nep->reason != NEP_CONVERGED_ITERATING || breakdown) l = 0;
1190:     else {
1191:       l = PetscMax(1,(PetscInt)((nv-k)*ctx->keep));
1192:       PetscCall(DSGetTruncateSize(nep->ds,k,nv,&l));
1193:       if (!breakdown) {
1194:         /* Prepare the Rayleigh quotient for restart */
1195:         PetscCall(DSGetDimensions(nep->ds,&dsn,NULL,&dsk,NULL));
1196:         PetscCall(DSSetDimensions(nep->ds,dsn,k,dsk));
1197:         PetscCall(DSTruncate(nep->ds,k+l,PETSC_FALSE));
1198:       }
1199:     }
1200:     nconv = k;
1201:     if (!ctx->lock && nep->reason == NEP_CONVERGED_ITERATING && !breakdown) { l += k; k = 0; }
1202:     if (l) PetscCall(PetscInfo(nep,"Preparing to restart keeping l=%" PetscInt_FMT " vectors\n",l));

1204:     /* Update S */
1205:     PetscCall(DSGetMat(nep->ds,ctx->nshifts?DS_MAT_Z:DS_MAT_Q,&MQ));
1206:     PetscCall(BVMultInPlace(ctx->V,MQ,nep->nconv,k+l));
1207:     PetscCall(DSRestoreMat(nep->ds,ctx->nshifts?DS_MAT_Z:DS_MAT_Q,&MQ));

1209:     /* Copy last column of S */
1210:     PetscCall(BVCopyColumn(ctx->V,nv,k+l));

1212:     if (breakdown && nep->reason == NEP_CONVERGED_ITERATING) {
1213:       /* Stop if breakdown */
1214:       PetscCall(PetscInfo(nep,"Breakdown (it=%" PetscInt_FMT " norm=%g)\n",nep->its,(double)betah));
1215:       nep->reason = NEP_DIVERGED_BREAKDOWN;
1216:     }
1217:     if (nep->reason != NEP_CONVERGED_ITERATING) l--;
1218:     /* truncate S */
1219:     PetscCall(BVGetActiveColumns(nep->V,NULL,&nq));
1220:     if (k+l+deg<=nq) {
1221:       PetscCall(BVSetActiveColumns(ctx->V,nep->nconv,k+l+1));
1222:       if (!falselock && ctx->lock) PetscCall(BVTensorCompress(ctx->V,k-nep->nconv));
1223:       else PetscCall(BVTensorCompress(ctx->V,0));
1224:     }
1225:     nep->nconv = k;
1226:     if (!ctx->nshifts) {
1227:       for (i=0;i<nv;i++) { eigr[i] = nep->eigr[i]; eigi[i] = nep->eigi[i]; }
1228:       PetscCall(NEPNLEIGSBackTransform((PetscObject)nep,nv,eigr,eigi));
1229:     }
1230:     PetscCall(NEPMonitor(nep,nep->its,nconv,eigr,eigi,nep->errest,nv));
1231:   }
1232:   nep->nconv = nconv;
1233:   if (nep->nconv>0) {
1234:     PetscCall(BVSetActiveColumns(ctx->V,0,nep->nconv));
1235:     PetscCall(BVGetActiveColumns(nep->V,NULL,&nq));
1236:     PetscCall(BVSetActiveColumns(nep->V,0,nq));
1237:     if (nq>nep->nconv) {
1238:       PetscCall(BVTensorCompress(ctx->V,nep->nconv));
1239:       PetscCall(BVSetActiveColumns(nep->V,0,nep->nconv));
1240:       nq = nep->nconv;
1241:     }
1242:     if (ctx->nshifts) {
1243:       PetscCall(DSGetMat(nep->ds,DS_MAT_B,&MQ));
1244:       PetscCall(BVMultInPlace(ctx->V,MQ,0,nep->nconv));
1245:       PetscCall(DSRestoreMat(nep->ds,DS_MAT_B,&MQ));
1246:     }
1247:     PetscCall(BVTensorGetFactors(ctx->V,NULL,&MS));
1248:     PetscCall(MatDenseGetArrayRead(MS,&S));
1249:     PetscCall(PetscMalloc1(nq*nep->nconv,&pU));
1250:     for (i=0;i<nep->nconv;i++) PetscCall(PetscArraycpy(pU+i*nq,S+i*lds,nq));
1251:     PetscCall(MatDenseRestoreArrayRead(MS,&S));
1252:     PetscCall(BVTensorRestoreFactors(ctx->V,NULL,&MS));
1253:     PetscCall(MatCreateSeqDense(PETSC_COMM_SELF,nq,nep->nconv,pU,&U));
1254:     PetscCall(BVSetActiveColumns(nep->V,0,nq));
1255:     PetscCall(BVMultInPlace(nep->V,U,0,nep->nconv));
1256:     PetscCall(BVSetActiveColumns(nep->V,0,nep->nconv));
1257:     PetscCall(MatDestroy(&U));
1258:     PetscCall(PetscFree(pU));
1259:     PetscCall(DSTruncate(nep->ds,nep->nconv,PETSC_TRUE));
1260:   }

1262:   /* Map eigenvalues back to the original problem */
1263:   if (!ctx->nshifts) {
1264:     PetscCall(NEPNLEIGSBackTransform((PetscObject)nep,nep->nconv,nep->eigr,nep->eigi));
1265:     PetscCall(PetscFree2(eigr,eigi));
1266:   }
1267:   PetscCall(BVDestroy(&W));
1268:   PetscFunctionReturn(PETSC_SUCCESS);
1269: }

1271: static PetscErrorCode NEPNLEIGSSetSingularitiesFunction_NLEIGS(NEP nep,NEPNLEIGSSingularitiesFn *fun,PetscCtx ctx)
1272: {
1273:   NEP_NLEIGS *nepctx=(NEP_NLEIGS*)nep->data;

1275:   PetscFunctionBegin;
1276:   if (fun) nepctx->computesingularities = fun;
1277:   if (ctx) nepctx->singularitiesctx     = ctx;
1278:   nep->state = NEP_STATE_INITIAL;
1279:   PetscFunctionReturn(PETSC_SUCCESS);
1280: }

1282: /*@
1283:    NEPNLEIGSSetSingularitiesFunction - Sets a user-defined callback function
1284:    to compute a discretization of the singularity set (the values where
1285:    $T(\cdot)$ is not analytic).

1287:    Logically Collective

1289:    Input Parameters:
1290: +  nep - the nonlinear eigensolver context
1291: .  fun - user function (if `NULL` then `NEP` retains any previously set value)
1292: -  ctx - [optional] user-defined context for private data for the function
1293:          (may be `NULL`, in which case `NEP` retains any previously set value)

1295:    Notes:
1296:    If the problem type has been set to `NEP_RATIONAL` with `NEPSetProblemType()`,
1297:    then it is not necessary to set the singularities explicitly since the
1298:    solver will try to determine them automatically.

1300:    If the problem is `NEP_GENERAL`, it is also possible to omit the
1301:    singularities callback. In that case, a discretization of the singularity
1302:    set is approximated via the AAA algorithm {cite:p}`Nak18,Els19`.

1304:    Level: intermediate

1306: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSGetSingularitiesFunction()`, `NEPSetProblemType()`
1307: @*/
1308: PetscErrorCode NEPNLEIGSSetSingularitiesFunction(NEP nep,NEPNLEIGSSingularitiesFn *fun,PetscCtx ctx)
1309: {
1310:   PetscFunctionBegin;
1312:   PetscTryMethod(nep,"NEPNLEIGSSetSingularitiesFunction_C",(NEP,NEPNLEIGSSingularitiesFn*,PetscCtx),(nep,fun,ctx));
1313:   PetscFunctionReturn(PETSC_SUCCESS);
1314: }

1316: static PetscErrorCode NEPNLEIGSGetSingularitiesFunction_NLEIGS(NEP nep,NEPNLEIGSSingularitiesFn **fun,PetscCtxRt ctx)
1317: {
1318:   NEP_NLEIGS *nepctx=(NEP_NLEIGS*)nep->data;

1320:   PetscFunctionBegin;
1321:   if (fun) *fun = nepctx->computesingularities;
1322:   if (ctx) *(void**)ctx = nepctx->singularitiesctx;
1323:   PetscFunctionReturn(PETSC_SUCCESS);
1324: }

1326: /*@
1327:    NEPNLEIGSGetSingularitiesFunction - Returns the callback function and optionally the user
1328:    provided context for computing a discretization of the singularity set.

1330:    Not Collective

1332:    Input Parameter:
1333: .  nep - the nonlinear eigensolver context

1335:    Output Parameters:
1336: +  fun - location to put the function (or `NULL`)
1337: -  ctx - location to stash the function context (or `NULL`)

1339:    Level: intermediate

1341: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSSetSingularitiesFunction()`
1342: @*/
1343: PetscErrorCode NEPNLEIGSGetSingularitiesFunction(NEP nep,NEPNLEIGSSingularitiesFn **fun,PetscCtxRt ctx)
1344: {
1345:   PetscFunctionBegin;
1347:   PetscUseMethod(nep,"NEPNLEIGSGetSingularitiesFunction_C",(NEP,NEPNLEIGSSingularitiesFn**,PetscCtxRt),(nep,fun,ctx));
1348:   PetscFunctionReturn(PETSC_SUCCESS);
1349: }

1351: static PetscErrorCode NEPNLEIGSSetRestart_NLEIGS(NEP nep,PetscReal keep)
1352: {
1353:   NEP_NLEIGS *ctx=(NEP_NLEIGS*)nep->data;

1355:   PetscFunctionBegin;
1356:   if (keep==(PetscReal)PETSC_DEFAULT || keep==(PetscReal)PETSC_DECIDE) ctx->keep = 0.5;
1357:   else {
1358:     PetscCheck(keep>=0.1 && keep<=0.9,PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"The keep argument must be in the range [0.1,0.9]");
1359:     ctx->keep = keep;
1360:   }
1361:   PetscFunctionReturn(PETSC_SUCCESS);
1362: }

1364: /*@
1365:    NEPNLEIGSSetRestart - Sets the restart parameter for the NLEIGS
1366:    method, in particular the proportion of basis vectors that must be kept
1367:    after restart.

1369:    Logically Collective

1371:    Input Parameters:
1372: +  nep  - the nonlinear eigensolver context
1373: -  keep - the number of vectors to be kept at restart

1375:    Options Database Key:
1376: .  -nep_nleigs_restart keep - sets the restart parameter

1378:    Notes:
1379:    Allowed values are in the range [0.1,0.9]. The default is 0.5.

1381:    Level: advanced

1383: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSGetRestart()`
1384: @*/
1385: PetscErrorCode NEPNLEIGSSetRestart(NEP nep,PetscReal keep)
1386: {
1387:   PetscFunctionBegin;
1390:   PetscTryMethod(nep,"NEPNLEIGSSetRestart_C",(NEP,PetscReal),(nep,keep));
1391:   PetscFunctionReturn(PETSC_SUCCESS);
1392: }

1394: static PetscErrorCode NEPNLEIGSGetRestart_NLEIGS(NEP nep,PetscReal *keep)
1395: {
1396:   NEP_NLEIGS *ctx=(NEP_NLEIGS*)nep->data;

1398:   PetscFunctionBegin;
1399:   *keep = ctx->keep;
1400:   PetscFunctionReturn(PETSC_SUCCESS);
1401: }

1403: /*@
1404:    NEPNLEIGSGetRestart - Gets the restart parameter used in the NLEIGS method.

1406:    Not Collective

1408:    Input Parameter:
1409: .  nep - the nonlinear eigensolver context

1411:    Output Parameter:
1412: .  keep - the restart parameter

1414:    Level: advanced

1416: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSSetRestart()`
1417: @*/
1418: PetscErrorCode NEPNLEIGSGetRestart(NEP nep,PetscReal *keep)
1419: {
1420:   PetscFunctionBegin;
1422:   PetscAssertPointer(keep,2);
1423:   PetscUseMethod(nep,"NEPNLEIGSGetRestart_C",(NEP,PetscReal*),(nep,keep));
1424:   PetscFunctionReturn(PETSC_SUCCESS);
1425: }

1427: static PetscErrorCode NEPNLEIGSSetLocking_NLEIGS(NEP nep,PetscBool lock)
1428: {
1429:   NEP_NLEIGS *ctx=(NEP_NLEIGS*)nep->data;

1431:   PetscFunctionBegin;
1432:   ctx->lock = lock;
1433:   PetscFunctionReturn(PETSC_SUCCESS);
1434: }

1436: /*@
1437:    NEPNLEIGSSetLocking - Choose between locking and non-locking variants of
1438:    the NLEIGS method.

1440:    Logically Collective

1442:    Input Parameters:
1443: +  nep  - the nonlinear eigensolver context
1444: -  lock - true if the locking variant must be selected

1446:    Options Database Key:
1447: .  -nep_nleigs_locking (true|false) - sets the locking flag

1449:    Notes:
1450:    The default is to lock converged eigenpairs when the method restarts.
1451:    This behavior can be changed so that all directions are kept in the
1452:    working subspace even if already converged to working accuracy (the
1453:    non-locking variant).

1455:    Level: advanced

1457: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSGetLocking()`
1458: @*/
1459: PetscErrorCode NEPNLEIGSSetLocking(NEP nep,PetscBool lock)
1460: {
1461:   PetscFunctionBegin;
1464:   PetscTryMethod(nep,"NEPNLEIGSSetLocking_C",(NEP,PetscBool),(nep,lock));
1465:   PetscFunctionReturn(PETSC_SUCCESS);
1466: }

1468: static PetscErrorCode NEPNLEIGSGetLocking_NLEIGS(NEP nep,PetscBool *lock)
1469: {
1470:   NEP_NLEIGS *ctx=(NEP_NLEIGS*)nep->data;

1472:   PetscFunctionBegin;
1473:   *lock = ctx->lock;
1474:   PetscFunctionReturn(PETSC_SUCCESS);
1475: }

1477: /*@
1478:    NEPNLEIGSGetLocking - Gets the locking flag used in the NLEIGS method.

1480:    Not Collective

1482:    Input Parameter:
1483: .  nep - the nonlinear eigensolver context

1485:    Output Parameter:
1486: .  lock - the locking flag

1488:    Level: advanced

1490: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSSetLocking()`
1491: @*/
1492: PetscErrorCode NEPNLEIGSGetLocking(NEP nep,PetscBool *lock)
1493: {
1494:   PetscFunctionBegin;
1496:   PetscAssertPointer(lock,2);
1497:   PetscUseMethod(nep,"NEPNLEIGSGetLocking_C",(NEP,PetscBool*),(nep,lock));
1498:   PetscFunctionReturn(PETSC_SUCCESS);
1499: }

1501: static PetscErrorCode NEPNLEIGSSetInterpolation_NLEIGS(NEP nep,PetscReal tol,PetscInt degree)
1502: {
1503:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;

1505:   PetscFunctionBegin;
1506:   if (tol == (PetscReal)PETSC_DETERMINE) {
1507:     ctx->ddtol = PETSC_DETERMINE;
1508:     nep->state = NEP_STATE_INITIAL;
1509:   } else if (tol != (PetscReal)PETSC_CURRENT) {
1510:     PetscCheck(tol>0.0,PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of tol. Must be > 0");
1511:     ctx->ddtol = tol;
1512:   }
1513:   if (degree == PETSC_DETERMINE) {
1514:     ctx->ddmaxit = 0;
1515:     if (nep->state) PetscCall(NEPReset(nep));
1516:     nep->state = NEP_STATE_INITIAL;
1517:   } else if (degree != PETSC_CURRENT) {
1518:     PetscCheck(degree>0,PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_OUTOFRANGE,"Illegal value of degree. Must be > 0");
1519:     if (ctx->ddmaxit != degree) {
1520:       ctx->ddmaxit = degree;
1521:       if (nep->state) PetscCall(NEPReset(nep));
1522:       nep->state = NEP_STATE_INITIAL;
1523:     }
1524:   }
1525:   PetscFunctionReturn(PETSC_SUCCESS);
1526: }

1528: /*@
1529:    NEPNLEIGSSetInterpolation - Sets the tolerance and maximum degree
1530:    when building the interpolation via divided differences.

1532:    Collective

1534:    Input Parameters:
1535: +  nep    - the nonlinear eigensolver context
1536: .  tol    - tolerance to stop computing divided differences
1537: -  degree - maximum degree of interpolation

1539:    Options Database Keys:
1540: +  -nep_nleigs_interpolation_tol tol       - sets the tolerance to stop computing divided differences
1541: -  -nep_nleigs_interpolation_degree degree - sets the maximum degree of interpolation

1543:    Note:
1544:    `PETSC_CURRENT` can be used to preserve the current value of any of the
1545:    arguments, and `PETSC_DETERMINE` to set them to a default value.

1547:    Level: advanced

1549: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSGetInterpolation()`
1550: @*/
1551: PetscErrorCode NEPNLEIGSSetInterpolation(NEP nep,PetscReal tol,PetscInt degree)
1552: {
1553:   PetscFunctionBegin;
1557:   PetscTryMethod(nep,"NEPNLEIGSSetInterpolation_C",(NEP,PetscReal,PetscInt),(nep,tol,degree));
1558:   PetscFunctionReturn(PETSC_SUCCESS);
1559: }

1561: static PetscErrorCode NEPNLEIGSGetInterpolation_NLEIGS(NEP nep,PetscReal *tol,PetscInt *degree)
1562: {
1563:   NEP_NLEIGS *ctx=(NEP_NLEIGS*)nep->data;

1565:   PetscFunctionBegin;
1566:   if (tol)    *tol    = ctx->ddtol;
1567:   if (degree) *degree = ctx->ddmaxit;
1568:   PetscFunctionReturn(PETSC_SUCCESS);
1569: }

1571: /*@
1572:    NEPNLEIGSGetInterpolation - Gets the tolerance and maximum degree
1573:    when building the interpolation via divided differences.

1575:    Not Collective

1577:    Input Parameter:
1578: .  nep - the nonlinear eigensolver context

1580:    Output Parameters:
1581: +  tol    - tolerance to stop computing divided differences
1582: -  degree - maximum degree of interpolation

1584:    Level: advanced

1586: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSSetInterpolation()`
1587: @*/
1588: PetscErrorCode NEPNLEIGSGetInterpolation(NEP nep,PetscReal *tol,PetscInt *degree)
1589: {
1590:   PetscFunctionBegin;
1592:   PetscTryMethod(nep,"NEPNLEIGSGetInterpolation_C",(NEP,PetscReal*,PetscInt*),(nep,tol,degree));
1593:   PetscFunctionReturn(PETSC_SUCCESS);
1594: }

1596: static PetscErrorCode NEPNLEIGSSetRKShifts_NLEIGS(NEP nep,PetscInt ns,PetscScalar *shifts)
1597: {
1598:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
1599:   PetscInt       i;

1601:   PetscFunctionBegin;
1602:   PetscCheck(ns>=0,PetscObjectComm((PetscObject)nep),PETSC_ERR_ARG_WRONG,"Number of shifts must be non-negative");
1603:   if (ctx->nshifts) PetscCall(PetscFree(ctx->shifts));
1604:   for (i=0;i<ctx->nshiftsw;i++) PetscCall(KSPDestroy(&ctx->ksp[i]));
1605:   PetscCall(PetscFree(ctx->ksp));
1606:   ctx->ksp = NULL;
1607:   if (ns) {
1608:     PetscCall(PetscMalloc1(ns,&ctx->shifts));
1609:     for (i=0;i<ns;i++) ctx->shifts[i] = shifts[i];
1610:   }
1611:   ctx->nshifts = ns;
1612:   nep->state   = NEP_STATE_INITIAL;
1613:   PetscFunctionReturn(PETSC_SUCCESS);
1614: }

1616: /*@
1617:    NEPNLEIGSSetRKShifts - Sets a list of shifts to be used in the Rational
1618:    Krylov method.

1620:    Collective

1622:    Input Parameters:
1623: +  nep    - the nonlinear eigensolver context
1624: .  ns     - number of shifts
1625: -  shifts - array of scalar values specifying the shifts

1627:    Options Database Key:
1628: .  -nep_nleigs_rk_shifts s0,s1,... - sets the list of shifts

1630:    Notes:
1631:    If only one shift is provided, the built subspace is equivalent to
1632:    shift-and-invert Krylov-Schur (provided that the absolute convergence
1633:    criterion is used). Otherwise, the rational Krylov variant is run.

1635:    In the case of real scalars, complex shifts are not allowed. In the
1636:    command line, a comma-separated list of complex values can be provided with
1637:    the format `[+/-][realnumber][+/-]realnumberi` with no spaces, e.g.
1638:    `-nep_nleigs_rk_shifts 1.0+2.0i,1.5+2.0i,1.0+1.5i`.

1640:    Use `ns=0` to remove previously set shifts.

1642:    Level: advanced

1644: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSGetRKShifts()`
1645: @*/
1646: PetscErrorCode NEPNLEIGSSetRKShifts(NEP nep,PetscInt ns,PetscScalar shifts[])
1647: {
1648:   PetscFunctionBegin;
1651:   if (ns) PetscAssertPointer(shifts,3);
1652:   PetscTryMethod(nep,"NEPNLEIGSSetRKShifts_C",(NEP,PetscInt,PetscScalar*),(nep,ns,shifts));
1653:   PetscFunctionReturn(PETSC_SUCCESS);
1654: }

1656: static PetscErrorCode NEPNLEIGSGetRKShifts_NLEIGS(NEP nep,PetscInt *ns,PetscScalar **shifts)
1657: {
1658:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
1659:   PetscInt       i;

1661:   PetscFunctionBegin;
1662:   *ns = ctx->nshifts;
1663:   if (ctx->nshifts) {
1664:     PetscCall(PetscMalloc1(ctx->nshifts,shifts));
1665:     for (i=0;i<ctx->nshifts;i++) (*shifts)[i] = ctx->shifts[i];
1666:   }
1667:   PetscFunctionReturn(PETSC_SUCCESS);
1668: }

1670: /*@
1671:    NEPNLEIGSGetRKShifts - Gets the list of shifts used in the Rational
1672:    Krylov method.

1674:    Not Collective

1676:    Input Parameter:
1677: .  nep - the nonlinear eigensolver context

1679:    Output Parameters:
1680: +  ns     - number of shifts
1681: -  shifts - array of shifts

1683:    Note:
1684:    The user is responsible for deallocating the returned array.

1686:    Level: advanced

1688: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSSetRKShifts()`
1689: @*/
1690: PetscErrorCode NEPNLEIGSGetRKShifts(NEP nep,PetscInt *ns,PetscScalar *shifts[]) PeNS
1691: {
1692:   PetscFunctionBegin;
1694:   PetscAssertPointer(ns,2);
1695:   PetscAssertPointer(shifts,3);
1696:   PetscTryMethod(nep,"NEPNLEIGSGetRKShifts_C",(NEP,PetscInt*,PetscScalar**),(nep,ns,shifts));
1697:   PetscFunctionReturn(PETSC_SUCCESS);
1698: }

1700: static PetscErrorCode NEPNLEIGSGetKSPs_NLEIGS(NEP nep,PetscInt *nsolve,KSP **ksp)
1701: {
1702:   NEP_NLEIGS     *ctx = (NEP_NLEIGS*)nep->data;
1703:   PetscInt       i;
1704:   PC             pc;

1706:   PetscFunctionBegin;
1707:   if (!ctx->ksp) {
1708:     PetscCall(NEPNLEIGSSetShifts(nep,&ctx->nshiftsw));
1709:     PetscCall(PetscMalloc1(ctx->nshiftsw,&ctx->ksp));
1710:     for (i=0;i<ctx->nshiftsw;i++) {
1711:       PetscCall(KSPCreate(PetscObjectComm((PetscObject)nep),&ctx->ksp[i]));
1712:       PetscCall(PetscObjectIncrementTabLevel((PetscObject)ctx->ksp[i],(PetscObject)nep,1));
1713:       PetscCall(KSPSetOptionsPrefix(ctx->ksp[i],((PetscObject)nep)->prefix));
1714:       PetscCall(KSPAppendOptionsPrefix(ctx->ksp[i],"nep_nleigs_"));
1715:       PetscCall(PetscObjectSetOptions((PetscObject)ctx->ksp[i],((PetscObject)nep)->options));
1716:       PetscCall(KSPSetErrorIfNotConverged(ctx->ksp[i],PETSC_TRUE));
1717:       PetscCall(KSPSetTolerances(ctx->ksp[i],1e-3*SlepcDefaultTol(nep->tol),PETSC_CURRENT,PETSC_CURRENT,PETSC_CURRENT));
1718:       PetscCall(KSPGetPC(ctx->ksp[i],&pc));
1719:       if ((nep->fui==NEP_USER_INTERFACE_SPLIT && nep->P) || (nep->fui==NEP_USER_INTERFACE_CALLBACK && nep->function_pre!=nep->function)) {
1720:         PetscCall(KSPSetType(ctx->ksp[i],KSPBCGS));
1721:         PetscCall(PCSetType(pc,PCBJACOBI));
1722:       } else {
1723:         PetscCall(KSPSetType(ctx->ksp[i],KSPPREONLY));
1724:         PetscCall(PCSetType(pc,PCLU));
1725:       }
1726:     }
1727:   }
1728:   if (nsolve) *nsolve = ctx->nshiftsw;
1729:   if (ksp)    *ksp    = ctx->ksp;
1730:   PetscFunctionReturn(PETSC_SUCCESS);
1731: }

1733: /*@
1734:    NEPNLEIGSGetKSPs - Retrieve the array of linear solver objects associated with
1735:    the nonlinear eigenvalue solver.

1737:    Collective

1739:    Input Parameter:
1740: .  nep - the nonlinear eigensolver context

1742:    Output Parameters:
1743: +  nsolve - number of returned `KSP` objects
1744: -  ksp - array of linear solver object

1746:    Note:
1747:    The number of `KSP` objects is equal to the number of shifts provided by the user,
1748:    or 1 if the user did not provide shifts.

1750:    Level: advanced

1752: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSSetRKShifts()`
1753: @*/
1754: PetscErrorCode NEPNLEIGSGetKSPs(NEP nep,PetscInt *nsolve,KSP **ksp)
1755: {
1756:   PetscFunctionBegin;
1758:   PetscUseMethod(nep,"NEPNLEIGSGetKSPs_C",(NEP,PetscInt*,KSP**),(nep,nsolve,ksp));
1759:   PetscFunctionReturn(PETSC_SUCCESS);
1760: }

1762: static PetscErrorCode NEPNLEIGSSetFullBasis_NLEIGS(NEP nep,PetscBool fullbasis)
1763: {
1764:   NEP_NLEIGS *ctx=(NEP_NLEIGS*)nep->data;

1766:   PetscFunctionBegin;
1767:   if (fullbasis!=ctx->fullbasis) {
1768:     ctx->fullbasis = fullbasis;
1769:     nep->state     = NEP_STATE_INITIAL;
1770:     nep->useds     = PetscNot(fullbasis);
1771:   }
1772:   PetscFunctionReturn(PETSC_SUCCESS);
1773: }

1775: /*@
1776:    NEPNLEIGSSetFullBasis - Choose between TOAR-basis (default) and full-basis
1777:    variants of the NLEIGS method.

1779:    Logically Collective

1781:    Input Parameters:
1782: +  nep       - the nonlinear eigensolver context
1783: -  fullbasis - true if the full-basis variant must be selected

1785:    Options Database Key:
1786: .  -nep_nleigs_full_basis (true|false) - sets the full-basis flag

1788:    Notes:
1789:    The default is to use a compact representation of the Krylov basis, that is,
1790:    $V = (I \otimes U) S$, with a `BVTENSOR`. This behavior can be changed so that
1791:    the full basis $V$ is explicitly stored and operated with. This variant is more
1792:    expensive in terms of memory and computation, but is necessary in some cases,
1793:    particularly for two-sided computations, see `NEPSetTwoSided()`.

1795:    In the full-basis variant, the NLEIGS solver uses an `EPS` object to explicitly
1796:    solve the linearized eigenproblem, see `NEPNLEIGSGetEPS()`.

1798:    Level: advanced

1800: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSGetFullBasis()`, `NEPNLEIGSGetEPS()`, `NEPSetTwoSided()`, `BVCreateTensor()`
1801: @*/
1802: PetscErrorCode NEPNLEIGSSetFullBasis(NEP nep,PetscBool fullbasis)
1803: {
1804:   PetscFunctionBegin;
1807:   PetscTryMethod(nep,"NEPNLEIGSSetFullBasis_C",(NEP,PetscBool),(nep,fullbasis));
1808:   PetscFunctionReturn(PETSC_SUCCESS);
1809: }

1811: static PetscErrorCode NEPNLEIGSGetFullBasis_NLEIGS(NEP nep,PetscBool *fullbasis)
1812: {
1813:   NEP_NLEIGS *ctx=(NEP_NLEIGS*)nep->data;

1815:   PetscFunctionBegin;
1816:   *fullbasis = ctx->fullbasis;
1817:   PetscFunctionReturn(PETSC_SUCCESS);
1818: }

1820: /*@
1821:    NEPNLEIGSGetFullBasis - Gets the flag that indicates if NLEIGS is using the
1822:    full-basis variant.

1824:    Not Collective

1826:    Input Parameter:
1827: .  nep - the nonlinear eigensolver context

1829:    Output Parameter:
1830: .  fullbasis - the flag

1832:    Level: advanced

1834: .seealso: [](ch:nep), `NEPNLEIGS`, `NEPNLEIGSSetFullBasis()`
1835: @*/
1836: PetscErrorCode NEPNLEIGSGetFullBasis(NEP nep,PetscBool *fullbasis)
1837: {
1838:   PetscFunctionBegin;
1840:   PetscAssertPointer(fullbasis,2);
1841:   PetscUseMethod(nep,"NEPNLEIGSGetFullBasis_C",(NEP,PetscBool*),(nep,fullbasis));
1842:   PetscFunctionReturn(PETSC_SUCCESS);
1843: }

1845: #define SHIFTMAX 30

1847: static PetscErrorCode NEPSetFromOptions_NLEIGS(NEP nep,PetscOptionItems PetscOptionsObject)
1848: {
1849:   NEP_NLEIGS     *ctx = (NEP_NLEIGS*)nep->data;
1850:   PetscInt       i=0,k;
1851:   PetscBool      flg1,flg2,b;
1852:   PetscReal      r;
1853:   PetscScalar    array[SHIFTMAX];

1855:   PetscFunctionBegin;
1856:   PetscOptionsHeadBegin(PetscOptionsObject,"NEP NLEIGS Options");

1858:     PetscCall(PetscOptionsReal("-nep_nleigs_restart","Proportion of vectors kept after restart","NEPNLEIGSSetRestart",0.5,&r,&flg1));
1859:     if (flg1) PetscCall(NEPNLEIGSSetRestart(nep,r));

1861:     PetscCall(PetscOptionsBool("-nep_nleigs_locking","Choose between locking and non-locking variants","NEPNLEIGSSetLocking",PETSC_FALSE,&b,&flg1));
1862:     if (flg1) PetscCall(NEPNLEIGSSetLocking(nep,b));

1864:     PetscCall(PetscOptionsBool("-nep_nleigs_full_basis","Choose between TOAR and full-basis variants","NEPNLEIGSSetFullBasis",PETSC_FALSE,&b,&flg1));
1865:     if (flg1) PetscCall(NEPNLEIGSSetFullBasis(nep,b));

1867:     PetscCall(NEPNLEIGSGetInterpolation(nep,&r,&i));
1868:     if (!i) i = PETSC_DETERMINE;
1869:     PetscCall(PetscOptionsInt("-nep_nleigs_interpolation_degree","Maximum number of terms for interpolation via divided differences","NEPNLEIGSSetInterpolation",i,&i,&flg1));
1870:     PetscCall(PetscOptionsReal("-nep_nleigs_interpolation_tol","Tolerance for interpolation via divided differences","NEPNLEIGSSetInterpolation",r,&r,&flg2));
1871:     if (flg1 || flg2) PetscCall(NEPNLEIGSSetInterpolation(nep,r,i));

1873:     k = SHIFTMAX;
1874:     for (i=0;i<k;i++) array[i] = 0;
1875:     PetscCall(PetscOptionsScalarArray("-nep_nleigs_rk_shifts","Shifts for Rational Krylov","NEPNLEIGSSetRKShifts",array,&k,&flg1));
1876:     if (flg1) PetscCall(NEPNLEIGSSetRKShifts(nep,k,array));

1878:   PetscOptionsHeadEnd();

1880:   if (!ctx->ksp) PetscCall(NEPNLEIGSGetKSPs(nep,&ctx->nshiftsw,&ctx->ksp));
1881:   for (i=0;i<ctx->nshiftsw;i++) PetscCall(KSPSetFromOptions(ctx->ksp[i]));

1883:   if (ctx->fullbasis) {
1884:     if (!ctx->eps) PetscCall(NEPNLEIGSGetEPS(nep,&ctx->eps));
1885:     PetscCall(EPSSetFromOptions(ctx->eps));
1886:   }
1887:   PetscFunctionReturn(PETSC_SUCCESS);
1888: }

1890: static PetscErrorCode NEPView_NLEIGS(NEP nep,PetscViewer viewer)
1891: {
1892:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;
1893:   PetscBool      isascii;
1894:   PetscInt       i;
1895:   char           str[50];

1897:   PetscFunctionBegin;
1898:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii));
1899:   if (isascii) {
1900:     PetscCall(PetscViewerASCIIPrintf(viewer,"  %d%% of basis vectors kept after restart\n",(int)(100*ctx->keep)));
1901:     if (ctx->fullbasis) PetscCall(PetscViewerASCIIPrintf(viewer,"  using the full-basis variant\n"));
1902:     else PetscCall(PetscViewerASCIIPrintf(viewer,"  using the %slocking variant\n",ctx->lock?"":"non-"));
1903:     PetscCall(PetscViewerASCIIPrintf(viewer,"  divided difference terms: used=%" PetscInt_FMT ", max=%" PetscInt_FMT "\n",ctx->nmat,ctx->ddmaxit));
1904:     PetscCall(PetscViewerASCIIPrintf(viewer,"  tolerance for divided difference convergence: %g\n",(double)ctx->ddtol));
1905:     if (ctx->nshifts) {
1906:       PetscCall(PetscViewerASCIIPrintf(viewer,"  RK shifts: "));
1907:       PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_FALSE));
1908:       for (i=0;i<ctx->nshifts;i++) {
1909:         PetscCall(SlepcSNPrintfScalar(str,sizeof(str),ctx->shifts[i],PETSC_FALSE));
1910:         PetscCall(PetscViewerASCIIPrintf(viewer,"%s%s",str,(i<ctx->nshifts-1)?",":""));
1911:       }
1912:       PetscCall(PetscViewerASCIIPrintf(viewer,"\n"));
1913:       PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_TRUE));
1914:     }
1915:     if (!ctx->ksp) PetscCall(NEPNLEIGSGetKSPs(nep,&ctx->nshiftsw,&ctx->ksp));
1916:     PetscCall(PetscViewerASCIIPushTab(viewer));
1917:     PetscCall(KSPView(ctx->ksp[0],viewer));
1918:     PetscCall(PetscViewerASCIIPopTab(viewer));
1919:     if (ctx->fullbasis) {
1920:       if (!ctx->eps) PetscCall(NEPNLEIGSGetEPS(nep,&ctx->eps));
1921:       PetscCall(PetscViewerASCIIPushTab(viewer));
1922:       PetscCall(EPSView(ctx->eps,viewer));
1923:       PetscCall(PetscViewerASCIIPopTab(viewer));
1924:     }
1925:   }
1926:   PetscFunctionReturn(PETSC_SUCCESS);
1927: }

1929: static PetscErrorCode NEPReset_NLEIGS(NEP nep)
1930: {
1931:   PetscInt       k;
1932:   NEP_NLEIGS     *ctx=(NEP_NLEIGS*)nep->data;

1934:   PetscFunctionBegin;
1935:   if (nep->fui==NEP_USER_INTERFACE_SPLIT) PetscCall(PetscFree(ctx->coeffD));
1936:   else {
1937:     for (k=0;k<ctx->nmat;k++) PetscCall(MatDestroy(&ctx->D[k]));
1938:   }
1939:   PetscCall(PetscFree4(ctx->s,ctx->xi,ctx->beta,ctx->D));
1940:   for (k=0;k<ctx->nshiftsw;k++) PetscCall(KSPReset(ctx->ksp[k]));
1941:   PetscCall(VecDestroy(&ctx->vrn));
1942:   if (ctx->fullbasis) {
1943:     PetscCall(MatDestroy(&ctx->A));
1944:     PetscCall(EPSReset(ctx->eps));
1945:     for (k=0;k<4;k++) PetscCall(VecDestroy(&ctx->w[k]));
1946:   }
1947:   PetscFunctionReturn(PETSC_SUCCESS);
1948: }

1950: static PetscErrorCode NEPDestroy_NLEIGS(NEP nep)
1951: {
1952:   PetscInt       k;
1953:   NEP_NLEIGS     *ctx = (NEP_NLEIGS*)nep->data;

1955:   PetscFunctionBegin;
1956:   PetscCall(BVDestroy(&ctx->V));
1957:   for (k=0;k<ctx->nshiftsw;k++) PetscCall(KSPDestroy(&ctx->ksp[k]));
1958:   PetscCall(PetscFree(ctx->ksp));
1959:   if (ctx->nshifts) PetscCall(PetscFree(ctx->shifts));
1960:   if (ctx->fullbasis) PetscCall(EPSDestroy(&ctx->eps));
1961:   PetscCall(PetscFree(nep->data));
1962:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetSingularitiesFunction_C",NULL));
1963:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetSingularitiesFunction_C",NULL));
1964:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetRestart_C",NULL));
1965:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetRestart_C",NULL));
1966:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetLocking_C",NULL));
1967:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetLocking_C",NULL));
1968:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetInterpolation_C",NULL));
1969:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetInterpolation_C",NULL));
1970:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetRKShifts_C",NULL));
1971:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetRKShifts_C",NULL));
1972:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetKSPs_C",NULL));
1973:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetFullBasis_C",NULL));
1974:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetFullBasis_C",NULL));
1975:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetEPS_C",NULL));
1976:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetEPS_C",NULL));
1977:   PetscFunctionReturn(PETSC_SUCCESS);
1978: }

1980: /*MC
1981:    NEPNLEIGS - NEPNLEIGS = "nleigs" - The NLEIGS method.

1983:    Notes:
1984:    This solver implements the NLEIGS method {cite:p}`Gut14`, which
1985:    is based on rational interpolation followed by linearization.
1986:    In our implementation, the linear eigensolver for the linearization
1987:    operates with a compressed Krylov basis, as in the TOAR polynomial
1988:    eigensolver, see the detailed description in {cite:p}`Cam21`.

1990:    This method is particularly appropriate for nonlinear problems with
1991:    singularities. The solver will try to determine the singularities
1992:    automatically, but the user can also provide them with
1993:    `NEPNLEIGSSetSingularitiesFunction()`.

1995:    By default, the solver performs the static NLEIGS variant, with
1996:    constant shift given by `NEPSetTarget()`. But the dynamic variant
1997:    (rational Krylov) is also available if a list of shifts is given
1998:    in `NEPNLEIGSSetRKShifts()`.

2000:    `NEPNLEIGS` also implements a two-sided variant for computing left
2001:    eigenvectors when `NEPSetTwoSided()` has been set.

2003:    Apart from working with the compressed basis, it is also possible
2004:    to enable the operation with an explicit basis for the linear
2005:    eigensolver, see `NEPNLEIGSSetFullBasis()`. This allows using
2006:    other eigensolvers via an `EPS` object obtained with `NEPNLEIGSGetEPS()`.
2007:    Also, the explicit basis is activated in the two-sided variant.

2009:    Level: beginner

2011: .seealso: [](ch:nep), `NEP`, `NEPType`, `NEPSetType()`, `NEPNLEIGSSetSingularitiesFunction()`, `NEPSetTarget()`, `NEPNLEIGSSetRKShifts()`, `NEPNLEIGSSetFullBasis()`, `NEPNLEIGSGetEPS()`, `NEPSetTwoSided()`
2012: M*/
2013: SLEPC_EXTERN PetscErrorCode NEPCreate_NLEIGS(NEP nep)
2014: {
2015:   NEP_NLEIGS     *ctx;

2017:   PetscFunctionBegin;
2018:   PetscCall(PetscNew(&ctx));
2019:   nep->data  = (void*)ctx;
2020:   ctx->lock  = PETSC_TRUE;
2021:   ctx->ddtol = PETSC_DETERMINE;

2023:   nep->useds = PETSC_TRUE;

2025:   nep->ops->setup          = NEPSetUp_NLEIGS;
2026:   nep->ops->setfromoptions = NEPSetFromOptions_NLEIGS;
2027:   nep->ops->view           = NEPView_NLEIGS;
2028:   nep->ops->destroy        = NEPDestroy_NLEIGS;
2029:   nep->ops->reset          = NEPReset_NLEIGS;

2031:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetSingularitiesFunction_C",NEPNLEIGSSetSingularitiesFunction_NLEIGS));
2032:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetSingularitiesFunction_C",NEPNLEIGSGetSingularitiesFunction_NLEIGS));
2033:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetRestart_C",NEPNLEIGSSetRestart_NLEIGS));
2034:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetRestart_C",NEPNLEIGSGetRestart_NLEIGS));
2035:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetLocking_C",NEPNLEIGSSetLocking_NLEIGS));
2036:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetLocking_C",NEPNLEIGSGetLocking_NLEIGS));
2037:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetInterpolation_C",NEPNLEIGSSetInterpolation_NLEIGS));
2038:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetInterpolation_C",NEPNLEIGSGetInterpolation_NLEIGS));
2039:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetRKShifts_C",NEPNLEIGSSetRKShifts_NLEIGS));
2040:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetRKShifts_C",NEPNLEIGSGetRKShifts_NLEIGS));
2041:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetKSPs_C",NEPNLEIGSGetKSPs_NLEIGS));
2042:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetFullBasis_C",NEPNLEIGSSetFullBasis_NLEIGS));
2043:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetFullBasis_C",NEPNLEIGSGetFullBasis_NLEIGS));
2044:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSSetEPS_C",NEPNLEIGSSetEPS_NLEIGS));
2045:   PetscCall(PetscObjectComposeFunction((PetscObject)nep,"NEPNLEIGSGetEPS_C",NEPNLEIGSGetEPS_NLEIGS));
2046:   PetscFunctionReturn(PETSC_SUCCESS);
2047: }