Actual source code: nrefine.c
slepc-3.10.1 2018-10-23
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2018, 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:    Newton refinement for polynomial eigenproblems.

     13:    References:

     15:        [1] T. Betcke and D. Kressner, "Perturbation, extraction and refinement
     16:            of invariant pairs for matrix polynomials", Linear Algebra Appl.
     17:            435(3):514-536, 2011.

     19:        [2] C. Campos and J.E. Roman, "Parallel iterative refinement in
     20:            polynomial eigenvalue problems", Numer. Linear Algebra Appl. 23(4):
     21:            730-745, 2016.
     22: */

     24: #include <slepc/private/pepimpl.h>
     25: #include <slepcblaslapack.h>

     27: typedef struct {
     28:   Mat          *A,M1;
     29:   BV           V,M2,M3,W;
     30:   PetscInt     k,nmat;
     31:   PetscScalar  *fih,*work,*M4;
     32:   PetscBLASInt *pM4;
     33:   PetscBool    compM1;
     34:   Vec          t;
     35: } FSubctx;

     37: typedef struct {
     38:   Mat          E[2],M1;
     39:   Vec          tN,ttN,t1,vseq;
     40:   VecScatter   scatterctx;
     41:   PetscBool    compM1;
     42:   PetscInt     *map0,*map1,*idxg,*idxp;
     43:   PetscSubcomm subc;
     44:   VecScatter   scatter_sub;
     45:   VecScatter   *scatter_id,*scatterp_id;
     46:   Mat          *A;
     47:   BV           V,W,M2,M3,Wt;
     48:   PetscScalar  *M4,*w,*wt,*d,*dt;
     49:   Vec          t,tg,Rv,Vi,tp,tpg;
     50:   PetscInt     idx,*cols;
     51: } MatExplicitCtx;

     53: static PetscErrorCode MatFSMult(Mat M ,Vec x,Vec y)
     54: {
     55: #if defined(PETSC_MISSING_LAPACK_GETRS)
     57:   SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"GETRS - Lapack routine is unavailable");
     58: #else
     60:   FSubctx        *ctx;
     61:   PetscInt       k,i;
     62:   PetscScalar    *c;
     63:   PetscBLASInt   k_,one=1,info;

     66:   MatShellGetContext(M,&ctx);
     67:   VecCopy(x,ctx->t);
     68:   k    = ctx->k;
     69:   c    = ctx->work;
     70:   PetscBLASIntCast(k,&k_);
     71:   MatMult(ctx->M1,x,y);
     72:   VecConjugate(ctx->t);
     73:   BVDotVec(ctx->M3,ctx->t,c);
     74:   for (i=0;i<k;i++) c[i] = PetscConj(c[i]);
     75:   PetscStackCallBLAS("LAPACKgetrs",LAPACKgetrs_("N",&k_,&one,ctx->M4,&k_,ctx->pM4,c,&k_,&info));
     76:   SlepcCheckLapackInfo("getrs",info);
     77:   BVMultVec(ctx->M2,-1.0,1.0,y,c);
     78:   return(0);
     79: #endif
     80: }

     82: /*
     83:   Evaluates the first d elements of the polynomial basis
     84:   on a given matrix H which is considered to be triangular
     85: */
     86: static PetscErrorCode PEPEvaluateBasisforMatrix(PEP pep,PetscInt nm,PetscInt k,PetscScalar *H,PetscInt ldh,PetscScalar *fH)
     87: {
     89:   PetscInt       i,j,ldfh=nm*k,off,nmat=pep->nmat;
     90:   PetscReal      *a=pep->pbc,*b=pep->pbc+nmat,*g=pep->pbc+2*nmat,t;
     91:   PetscScalar    corr=0.0,alpha,beta;
     92:   PetscBLASInt   k_,ldh_,ldfh_;

     95:   PetscBLASIntCast(ldh,&ldh_);
     96:   PetscBLASIntCast(k,&k_);
     97:   PetscBLASIntCast(ldfh,&ldfh_);
     98:   PetscMemzero(fH,nm*k*k*sizeof(PetscScalar));
     99:   if (nm>0) for (j=0;j<k;j++) fH[j+j*ldfh] = 1.0;
    100:   if (nm>1) {
    101:     t = b[0]/a[0];
    102:     off = k;
    103:     for (j=0;j<k;j++) {
    104:       for (i=0;i<k;i++) fH[off+i+j*ldfh] = H[i+j*ldh]/a[0];
    105:       fH[j+j*ldfh] -= t;
    106:     }
    107:   }
    108:   for (i=2;i<nm;i++) {
    109:     off = i*k;
    110:     if (i==2) {
    111:       for (j=0;j<k;j++) {
    112:         fH[off+j+j*ldfh] = 1.0;
    113:         H[j+j*ldh] -= b[1];
    114:       }
    115:     } else {
    116:       for (j=0;j<k;j++) {
    117:         PetscMemcpy(fH+off+j*ldfh,fH+(i-2)*k+j*ldfh,k*sizeof(PetscScalar));
    118:         H[j+j*ldh] += corr-b[i-1];
    119:       }
    120:     }
    121:     corr  = b[i-1];
    122:     beta  = -g[i-1]/a[i-1];
    123:     alpha = 1/a[i-1];
    124:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&alpha,H,&ldh_,fH+(i-1)*k,&ldfh_,&beta,fH+off,&ldfh_));
    125:   }
    126:   for (j=0;j<k;j++) H[j+j*ldh] += corr;
    127:   return(0);
    128: }

    130: static PetscErrorCode NRefSysSetup_shell(PEP pep,PetscInt k,PetscScalar *fH,PetscScalar *S,PetscInt lds,PetscScalar *fh,PetscScalar h,FSubctx *ctx)
    131: {
    132: #if defined(PETSC_MISSING_LAPACK_GESV)
    134:   SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"GESV - Lapack routine is unavailable");
    135: #else
    136:   PetscErrorCode    ierr;
    137:   PetscScalar       *DHii,*T12,*Tr,*Ts,*array,s,ss,sone=1.0,zero=0.0,*M4=ctx->M4,t,*v,*T;
    138:   const PetscScalar *m3,*m2;
    139:   PetscInt          i,d,j,nmat=pep->nmat,lda=nmat*k,deg=nmat-1,nloc;
    140:   PetscReal         *a=pep->pbc,*b=pep->pbc+nmat,*g=pep->pbc+2*nmat;
    141:   PetscBLASInt      k_,lda_,lds_,nloc_,one=1,info;
    142:   Mat               *A=ctx->A,Mk,M1=ctx->M1,P;
    143:   BV                V=ctx->V,M2=ctx->M2,M3=ctx->M3,W=ctx->W;
    144:   MatStructure      str;
    145:   Vec               vc;

    148:   STGetMatStructure(pep->st,&str);
    149:   PetscMalloc3(nmat*k*k,&T12,k*k,&Tr,PetscMax(k*k,nmat),&Ts);
    150:   DHii = T12;
    151:   PetscMemzero(DHii,k*k*nmat*sizeof(PetscScalar));
    152:   for (i=0;i<k;i++) DHii[k+i+i*lda] = 1.0/a[0];
    153:   for (d=2;d<nmat;d++) {
    154:     for (j=0;j<k;j++) {
    155:       for (i=0;i<k;i++) {
    156:         DHii[d*k+i+j*lda] = ((h-b[d-1])*DHii[(d-1)*k+i+j*lda]+fH[(d-1)*k+i+j*lda]-g[d-1]*DHii[(d-2)*k+i+j*lda])/(a[d-1]);
    157:       }
    158:     }
    159:   }
    160:   /* T11 */
    161:   if (!ctx->compM1) {
    162:     MatCopy(A[0],M1,DIFFERENT_NONZERO_PATTERN);
    163:     PEPEvaluateBasis(pep,h,0,Ts,NULL);
    164:     for (j=1;j<nmat;j++) {
    165:       MatAXPY(M1,Ts[j],A[j],str);
    166:     }
    167:   }

    169:   /* T22 */
    170:   PetscBLASIntCast(lds,&lds_);
    171:   PetscBLASIntCast(k,&k_);
    172:   PetscBLASIntCast(lda,&lda_);
    173:   PetscStackCallBLAS("BLASgemm",BLASgemm_("C","N",&k_,&k_,&k_,&sone,S,&lds_,S,&lds_,&zero,Tr,&k_));
    174:   for (i=1;i<deg;i++) {
    175:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,Tr,&k_,DHii+i*k,&lda_,&zero,Ts,&k_));
    176:     s = (i==1)?0.0:1.0;
    177:     PetscStackCallBLAS("BLASgemm",BLASgemm_("C","N",&k_,&k_,&k_,&sone,fH+i*k,&lda_,Ts,&k_,&s,M4,&k_));
    178:   }
    179:   for (i=0;i<k;i++) for (j=0;j<i;j++) { t=M4[i+j*k];M4[i+j*k]=M4[j+i*k];M4[j+i*k]=t; }

    181:   /* T12 */
    182:   MatCreateSeqDense(PETSC_COMM_SELF,k,k,NULL,&Mk);
    183:   for (i=1;i<nmat;i++) {
    184:     MatDenseGetArray(Mk,&array);
    185:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,S,&lds_,DHii+i*k,&lda_,&zero,array,&k_));
    186:     MatDenseRestoreArray(Mk,&array);
    187:     BVSetActiveColumns(W,0,k);
    188:     BVMult(W,1.0,0.0,V,Mk);
    189:     if (i==1) {
    190:       BVMatMult(W,A[i],M2);
    191:     } else {
    192:       BVMatMult(W,A[i],M3); /* using M3 as work space */
    193:       BVMult(M2,1.0,1.0,M3,NULL);
    194:     }
    195:   }

    197:   /* T21 */
    198:   MatDenseGetArray(Mk,&array);
    199:   for (i=1;i<deg;i++) {
    200:     s = (i==1)?0.0:1.0;
    201:     ss = PetscConj(fh[i]);
    202:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&ss,S,&lds_,fH+i*k,&lda_,&s,array,&k_));
    203:   }
    204:   MatDenseRestoreArray(Mk,&array);
    205:   BVSetActiveColumns(M3,0,k);
    206:   BVMult(M3,1.0,0.0,V,Mk);
    207:   for (i=0;i<k;i++) {
    208:     BVGetColumn(M3,i,&vc);
    209:     VecConjugate(vc);
    210:     BVRestoreColumn(M3,i,&vc);
    211:   }
    212:   MatDestroy(&Mk);
    213:   PetscFree3(T12,Tr,Ts);

    215:   VecGetLocalSize(ctx->t,&nloc);
    216:   PetscBLASIntCast(nloc,&nloc_);
    217:   PetscMalloc1(nloc*k,&T);
    218:   KSPGetOperators(pep->refineksp,NULL,&P);
    219:   if (!ctx->compM1) { MatCopy(ctx->M1,P,SAME_NONZERO_PATTERN); }
    220:   BVGetArrayRead(ctx->M2,&m2);
    221:   BVGetArrayRead(ctx->M3,&m3);
    222:   VecGetArray(ctx->t,&v);
    223:   for (i=0;i<nloc;i++) for (j=0;j<k;j++) T[j+i*k] = m3[i+j*nloc];
    224:   PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&k_,&nloc_,ctx->M4,&k_,ctx->pM4,T,&k_,&info));
    225:   SlepcCheckLapackInfo("gesv",info);
    226:   for (i=0;i<nloc;i++) v[i] = BLASdot_(&k_,m2+i,&nloc_,T+i*k,&one);
    227:   VecRestoreArray(ctx->t,&v);
    228:   BVRestoreArrayRead(ctx->M2,&m2);
    229:   BVRestoreArrayRead(ctx->M3,&m3);
    230:   MatDiagonalSet(P,ctx->t,ADD_VALUES);
    231:   PetscFree(T);
    232:   KSPSetUp(pep->refineksp);
    233:   return(0);
    234: #endif
    235: }

    237: static PetscErrorCode NRefSysSolve_shell(KSP ksp,PetscInt nmat,Vec Rv,PetscScalar *Rh,PetscInt k,Vec dVi,PetscScalar *dHi)
    238: {
    239: #if defined(PETSC_MISSING_LAPACK_GETRS)
    241:   SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"GETRS - Lapack routine is unavailable");
    242: #else
    244:   PetscScalar    *t0;
    245:   PetscBLASInt   k_,one=1,info,lda_;
    246:   PetscInt       i,lda=nmat*k;
    247:   Mat            M;
    248:   FSubctx        *ctx;

    251:   KSPGetOperators(ksp,&M,NULL);
    252:   MatShellGetContext(M,&ctx);
    253:   PetscCalloc1(k,&t0);
    254:   PetscBLASIntCast(lda,&lda_);
    255:   PetscBLASIntCast(k,&k_);
    256:   for (i=0;i<k;i++) t0[i] = Rh[i];
    257:   PetscStackCallBLAS("LAPACKgetrs",LAPACKgetrs_("N",&k_,&one,ctx->M4,&k_,ctx->pM4,t0,&k_,&info));
    258:   SlepcCheckLapackInfo("getrs",info);
    259:   BVMultVec(ctx->M2,-1.0,1.0,Rv,t0);
    260:   KSPSolve(ksp,Rv,dVi);
    261:   VecConjugate(dVi);
    262:   BVDotVec(ctx->M3,dVi,dHi);
    263:   VecConjugate(dVi);
    264:   for (i=0;i<k;i++) dHi[i] = Rh[i]-PetscConj(dHi[i]);
    265:   PetscStackCallBLAS("LAPACKgetrs",LAPACKgetrs_("N",&k_,&one,ctx->M4,&k_,ctx->pM4,dHi,&k_,&info));
    266:   SlepcCheckLapackInfo("getrs",info);
    267:   PetscFree(t0);
    268:   return(0);
    269: #endif
    270: }

    272: /*
    273:    Computes the residual P(H,V*S)*e_j for the polynomial
    274: */
    275: static PetscErrorCode NRefRightSide(PetscInt nmat,PetscReal *pcf,Mat *A,PetscInt k,BV V,PetscScalar *S,PetscInt lds,PetscInt j,PetscScalar *H,PetscInt ldh,PetscScalar *fH,PetscScalar *DfH,PetscScalar *dH,BV dV,PetscScalar *dVS,PetscInt rds,Vec Rv,PetscScalar *Rh,BV W,Vec t)
    276: {
    278:   PetscScalar    *DS0,*DS1,*F,beta=0.0,sone=1.0,none=-1.0,tt=0.0,*h,zero=0.0,*Z,*c0;
    279:   PetscReal      *a=pcf,*b=pcf+nmat,*g=b+nmat;
    280:   PetscInt       i,ii,jj,lda;
    281:   PetscBLASInt   lda_,k_,ldh_,lds_,nmat_,k2_,krds_,j_,one=1;
    282:   Mat            M0;
    283:   Vec            w;

    286:   PetscMalloc4(k*nmat,&h,k*k,&DS0,k*k,&DS1,k*k,&Z);
    287:   lda = k*nmat;
    288:   PetscBLASIntCast(k,&k_);
    289:   PetscBLASIntCast(lds,&lds_);
    290:   PetscBLASIntCast(lda,&lda_);
    291:   PetscBLASIntCast(nmat,&nmat_);
    292:   PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&nmat_,&k_,&sone,S,&lds_,fH+j*lda,&k_,&zero,h,&k_));
    293:   MatCreateSeqDense(PETSC_COMM_SELF,k,nmat,h,&M0);
    294:   BVSetActiveColumns(W,0,nmat);
    295:   BVMult(W,1.0,0.0,V,M0);
    296:   MatDestroy(&M0);

    298:   BVGetColumn(W,0,&w);
    299:   MatMult(A[0],w,Rv);
    300:   BVRestoreColumn(W,0,&w);
    301:   for (i=1;i<nmat;i++) {
    302:     BVGetColumn(W,i,&w);
    303:     MatMult(A[i],w,t);
    304:     BVRestoreColumn(W,i,&w);
    305:     VecAXPY(Rv,1.0,t);
    306:   }
    307:   /* Update right-hand side */
    308:   if (j) {
    309:     PetscBLASIntCast(ldh,&ldh_);
    310:     PetscMemzero(Z,k*k*sizeof(PetscScalar));
    311:     PetscMemzero(DS0,k*k*sizeof(PetscScalar));
    312:     PetscMemcpy(Z+(j-1)*k,dH+(j-1)*k,k*sizeof(PetscScalar));
    313:     /* Update DfH */
    314:     for (i=1;i<nmat;i++) {
    315:       if (i>1) {
    316:         beta = -g[i-1];
    317:         PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,fH+(i-1)*k,&lda_,Z,&k_,&beta,DS0,&k_));
    318:         tt += -b[i-1];
    319:         for (ii=0;ii<k;ii++) H[ii+ii*ldh] += tt;
    320:         tt = b[i-1];
    321:         beta = 1.0/a[i-1];
    322:         PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&beta,DS1,&k_,H,&ldh_,&beta,DS0,&k_));
    323:         F = DS0; DS0 = DS1; DS1 = F;
    324:       } else {
    325:         PetscMemzero(DS1,k*k*sizeof(PetscScalar));
    326:         for (ii=0;ii<k;ii++) DS1[ii+(j-1)*k] = Z[ii+(j-1)*k]/a[0];
    327:       }
    328:       for (jj=j;jj<k;jj++) {
    329:         for (ii=0;ii<k;ii++) DfH[k*i+ii+jj*lda] += DS1[ii+jj*k];
    330:       }
    331:     }
    332:     for (ii=0;ii<k;ii++) H[ii+ii*ldh] += tt;
    333:     /* Update right-hand side */
    334:     PetscBLASIntCast(2*k,&k2_);
    335:     PetscBLASIntCast(j,&j_);
    336:     PetscBLASIntCast(k+rds,&krds_);
    337:     c0 = DS0;
    338:     PetscMemzero(Rh,k*sizeof(PetscScalar));
    339:     for (i=0;i<nmat;i++) {
    340:       PetscStackCallBLAS("BLASgemv",BLASgemv_("N",&krds_,&j_,&sone,dVS,&k2_,fH+j*lda+i*k,&one,&zero,h,&one));
    341:       PetscStackCallBLAS("BLASgemv",BLASgemv_("N",&k_,&k_,&sone,S,&lds_,DfH+i*k+j*lda,&one,&sone,h,&one));
    342:       BVMultVec(V,1.0,0.0,t,h);
    343:       BVSetActiveColumns(dV,0,rds);
    344:       BVMultVec(dV,1.0,1.0,t,h+k);
    345:       BVGetColumn(W,i,&w);
    346:       MatMult(A[i],t,w);
    347:       BVRestoreColumn(W,i,&w);
    348:       if (i>0 && i<nmat-1) {
    349:         PetscStackCallBLAS("BLASgemv",BLASgemv_("C",&k_,&k_,&sone,S,&lds_,h,&one,&zero,c0,&one));
    350:         PetscStackCallBLAS("BLASgemv",BLASgemv_("C",&k_,&k_,&none,fH+i*k,&lda_,c0,&one,&sone,Rh,&one));
    351:       }
    352:     }

    354:     for (i=0;i<nmat;i++) h[i] = -1.0;
    355:     BVMultVec(W,1.0,1.0,Rv,h);
    356:   }
    357:   PetscFree4(h,DS0,DS1,Z);
    358:   return(0);
    359: }

    361: static PetscErrorCode NRefSysSolve_mbe(PetscInt k,PetscInt sz,BV W,PetscScalar *w,BV Wt,PetscScalar *wt,PetscScalar *d,PetscScalar *dt,KSP ksp,BV T2,BV T3 ,PetscScalar *T4,PetscBool trans,Vec x1,PetscScalar *x2,Vec sol1,PetscScalar *sol2,Vec vw)
    362: {
    364:   PetscInt       i,j,incf,incc;
    365:   PetscScalar    *y,*g,*xx2,*ww,y2,*dd;
    366:   Vec            v,t,xx1;
    367:   BV             WW,T;

    370:   PetscMalloc3(sz,&y,sz,&g,k,&xx2);
    371:   if (trans) {
    372:     WW = W; ww = w; dd = d; T = T3; incf = 0; incc = 1;
    373:   } else {
    374:     WW = Wt; ww = wt; dd = dt; T = T2; incf = 1; incc = 0;
    375:   }
    376:   xx1 = vw;
    377:   VecCopy(x1,xx1);
    378:   PetscMemcpy(xx2,x2,sz*sizeof(PetscScalar));
    379:   PetscMemzero(sol2,k*sizeof(PetscScalar));
    380:   for (i=sz-1;i>=0;i--) {
    381:     BVGetColumn(WW,i,&v);
    382:     VecConjugate(v);
    383:     VecDot(xx1,v,y+i);
    384:     VecConjugate(v);
    385:     BVRestoreColumn(WW,i,&v);
    386:     for (j=0;j<i;j++) y[i] += ww[j+i*k]*xx2[j];
    387:     y[i] = -(y[i]-xx2[i])/dd[i];
    388:     BVGetColumn(T,i,&t);
    389:     VecAXPY(xx1,-y[i],t);
    390:     BVRestoreColumn(T,i,&t);
    391:     for(j=0;j<=i;j++) xx2[j] -= y[i]*T4[j*incf+incc*i+(i*incf+incc*j)*k];
    392:     g[i] = xx2[i];
    393:   }
    394:   if (trans) {
    395:     KSPSolveTranspose(ksp,xx1,sol1);
    396:   } else {
    397:     KSPSolve(ksp,xx1,sol1);
    398:   }
    399:   if (trans) {
    400:     WW = Wt; ww = wt; dd = dt; T = T2; incf = 1; incc = 0;
    401:   } else {
    402:     WW = W; ww = w; dd = d; T = T3; incf = 0; incc = 1;
    403:   }
    404:   for (i=0;i<sz;i++) {
    405:     BVGetColumn(T,i,&t);
    406:     VecConjugate(t);
    407:     VecDot(sol1,t,&y2);
    408:     VecConjugate(t);
    409:     BVRestoreColumn(T,i,&t);
    410:     for (j=0;j<i;j++) y2 += sol2[j]*T4[j*incf+incc*i+(i*incf+incc*j)*k];
    411:     y2 = (g[i]-y2)/dd[i];
    412:     BVGetColumn(WW,i,&v);
    413:     VecAXPY(sol1,-y2,v);
    414:     for (j=0;j<i;j++) sol2[j] -= ww[j+i*k]*y2;
    415:     sol2[i] = y[i]+y2;
    416:     BVRestoreColumn(WW,i,&v);
    417:   }
    418:   PetscFree3(y,g,xx2);
    419:   return(0);
    420: }

    422: static PetscErrorCode NRefSysSetup_mbe(PEP pep,PetscInt k,KSP ksp,PetscScalar *fH,PetscScalar *S,PetscInt lds,PetscScalar *fh,PetscScalar h,BV V,MatExplicitCtx *matctx)
    423: {
    425:   PetscInt       i,j,l,nmat=pep->nmat,lda=nmat*k,deg=nmat-1;
    426:   Mat            M1=matctx->M1,*A,*At,Mk;
    427:   PetscReal      *a=pep->pbc,*b=pep->pbc+nmat,*g=pep->pbc+2*nmat;
    428:   PetscScalar    s,ss,*DHii,*T12,*array,*Ts,*Tr,*M4=matctx->M4,sone=1.0,zero=0.0;
    429:   PetscScalar    *w=matctx->w,*wt=matctx->wt,*d=matctx->d,*dt=matctx->dt;
    430:   PetscBLASInt   lds_,lda_,k_;
    431:   MatStructure   str;
    432:   PetscBool      flg;
    433:   BV             M2=matctx->M2,M3=matctx->M3,W=matctx->W,Wt=matctx->Wt;
    434:   Vec            vc,vc2;

    437:   PetscMalloc3(nmat*k*k,&T12,k*k,&Tr,PetscMax(k*k,nmat),&Ts);
    438:   STGetMatStructure(pep->st,&str);
    439:   STGetTransform(pep->st,&flg);
    440:   if (flg) {
    441:     PetscMalloc1(pep->nmat,&At);
    442:     for (i=0;i<pep->nmat;i++) {
    443:       STGetMatrixTransformed(pep->st,i,&At[i]);
    444:     }
    445:   } else At = pep->A;
    446:   if (matctx->subc) A = matctx->A;
    447:   else A = At;
    448:   /* Form the explicit system matrix */
    449:   DHii = T12;
    450:   PetscMemzero(DHii,k*k*nmat*sizeof(PetscScalar));
    451:   for (i=0;i<k;i++) DHii[k+i+i*lda] = 1.0/a[0];
    452:   for (l=2;l<nmat;l++) {
    453:     for (j=0;j<k;j++) {
    454:       for (i=0;i<k;i++) {
    455:         DHii[l*k+i+j*lda] = ((h-b[l-1])*DHii[(l-1)*k+i+j*lda]+fH[(l-1)*k+i+j*lda]-g[l-1]*DHii[(l-2)*k+i+j*lda])/a[l-1];
    456:       }
    457:     }
    458:   }

    460:   /* T11 */
    461:   if (!matctx->compM1) {
    462:     MatCopy(A[0],M1,DIFFERENT_NONZERO_PATTERN);
    463:     PEPEvaluateBasis(pep,h,0,Ts,NULL);
    464:     for (j=1;j<nmat;j++) {
    465:       MatAXPY(M1,Ts[j],A[j],str);
    466:     }
    467:   }

    469:   /* T22 */
    470:   PetscBLASIntCast(lds,&lds_);
    471:   PetscBLASIntCast(k,&k_);
    472:   PetscBLASIntCast(lda,&lda_);
    473:   PetscStackCallBLAS("BLASgemm",BLASgemm_("C","N",&k_,&k_,&k_,&sone,S,&lds_,S,&lds_,&zero,Tr,&k_));
    474:   for (i=1;i<deg;i++) {
    475:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,Tr,&k_,DHii+i*k,&lda_,&zero,Ts,&k_));
    476:     s = (i==1)?0.0:1.0;
    477:     PetscStackCallBLAS("BLASgemm",BLASgemm_("C","N",&k_,&k_,&k_,&sone,fH+i*k,&lda_,Ts,&k_,&s,M4,&k_));
    478:   }

    480:   /* T12 */
    481:   MatCreateSeqDense(PETSC_COMM_SELF,k,k,NULL,&Mk);
    482:   for (i=1;i<nmat;i++) {
    483:     MatDenseGetArray(Mk,&array);
    484:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,S,&lds_,DHii+i*k,&lda_,&zero,array,&k_));
    485:     MatDenseRestoreArray(Mk,&array);
    486:     BVSetActiveColumns(W,0,k);
    487:     BVMult(W,1.0,0.0,V,Mk);
    488:     if (i==1) {
    489:       BVMatMult(W,A[i],M2);
    490:     } else {
    491:       BVMatMult(W,A[i],M3); /* using M3 as work space */
    492:       BVMult(M2,1.0,1.0,M3,NULL);
    493:     }
    494:   }

    496:   /* T21 */
    497:   MatDenseGetArray(Mk,&array);
    498:   for (i=1;i<deg;i++) {
    499:     s = (i==1)?0.0:1.0;
    500:     ss = PetscConj(fh[i]);
    501:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&ss,S,&lds_,fH+i*k,&lda_,&s,array,&k_));
    502:   }
    503:   MatDenseRestoreArray(Mk,&array);
    504:   BVSetActiveColumns(M3,0,k);
    505:   BVMult(M3,1.0,0.0,V,Mk);
    506:   for (i=0;i<k;i++) {
    507:     BVGetColumn(M3,i,&vc);
    508:     VecConjugate(vc);
    509:     BVRestoreColumn(M3,i,&vc);
    510:   }

    512:   KSPSetOperators(ksp,M1,M1);
    513:   KSPSetUp(ksp);
    514:   MatDestroy(&Mk);

    516:   /* Set up for BEMW */
    517:   for (i=0;i<k;i++) {
    518:     BVGetColumn(M2,i,&vc);
    519:     BVGetColumn(W,i,&vc2);
    520:     NRefSysSolve_mbe(k,i,W,w,Wt,wt,d,dt,ksp,M2,M3,M4,PETSC_FALSE,vc,M4+i*k,vc2,w+i*k,matctx->t);
    521:     BVRestoreColumn(M2,i,&vc);
    522:     BVGetColumn(M3,i,&vc);
    523:     VecConjugate(vc);
    524:     VecDot(vc2,vc,&d[i]);
    525:     VecConjugate(vc);
    526:     BVRestoreColumn(M3,i,&vc);
    527:     for (j=0;j<i;j++) d[i] += M4[i+j*k]*w[j+i*k];
    528:     d[i] = M4[i+i*k]-d[i];
    529:     BVRestoreColumn(W,i,&vc2);

    531:     BVGetColumn(M3,i,&vc);
    532:     BVGetColumn(Wt,i,&vc2);
    533:     for (j=0;j<=i;j++) Ts[j] = M4[i+j*k];
    534:     NRefSysSolve_mbe(k,i,W,w,Wt,wt,d,dt,ksp,M2,M3,M4,PETSC_TRUE,vc,Ts,vc2,wt+i*k,matctx->t);
    535:     BVRestoreColumn(M3,i,&vc);
    536:     BVGetColumn(M2,i,&vc);
    537:     VecConjugate(vc2);
    538:     VecDot(vc,vc2,&dt[i]);
    539:     VecConjugate(vc2);
    540:     BVRestoreColumn(M2,i,&vc);
    541:     for (j=0;j<i;j++) dt[i] += M4[j+i*k]*wt[j+i*k];
    542:     dt[i] = M4[i+i*k]-dt[i];
    543:     BVRestoreColumn(Wt,i,&vc2);
    544:   }

    546:   if (flg) {
    547:     PetscFree(At);
    548:   }
    549:   PetscFree3(T12,Tr,Ts);
    550:   return(0);
    551: }

    553: static PetscErrorCode NRefSysSetup_explicit(PEP pep,PetscInt k,KSP ksp,PetscScalar *fH,PetscScalar *S,PetscInt lds,PetscScalar *fh,PetscScalar h,BV V,MatExplicitCtx *matctx,BV W)
    554: {
    555:   PetscErrorCode    ierr;
    556:   PetscInt          i,j,d,n,n0,m0,n1,m1,nmat=pep->nmat,lda=nmat*k,deg=nmat-1;
    557:   PetscInt          *idxg=matctx->idxg,*idxp=matctx->idxp,idx,ncols;
    558:   Mat               M,*E=matctx->E,*A,*At,Mk,Md;
    559:   PetscReal         *a=pep->pbc,*b=pep->pbc+nmat,*g=pep->pbc+2*nmat;
    560:   PetscScalar       s,ss,*DHii,*T22,*T21,*T12,*Ts,*Tr,*array,*ts,sone=1.0,zero=0.0;
    561:   PetscBLASInt      lds_,lda_,k_;
    562:   const PetscInt    *idxmc;
    563:   const PetscScalar *valsc,*carray;
    564:   MatStructure      str;
    565:   Vec               vc,vc0;
    566:   PetscBool         flg;

    569:   PetscMalloc5(k*k,&T22,k*k,&T21,nmat*k*k,&T12,k*k,&Tr,k*k,&Ts);
    570:   STGetMatStructure(pep->st,&str);
    571:   KSPGetOperators(ksp,&M,NULL);
    572:   MatGetOwnershipRange(E[1],&n1,&m1);
    573:   MatGetOwnershipRange(E[0],&n0,&m0);
    574:   MatGetOwnershipRange(M,&n,NULL);
    575:   PetscMalloc1(nmat,&ts);
    576:   STGetTransform(pep->st,&flg);
    577:   if (flg) {
    578:     PetscMalloc1(pep->nmat,&At);
    579:     for (i=0;i<pep->nmat;i++) {
    580:       STGetMatrixTransformed(pep->st,i,&At[i]);
    581:     }
    582:   } else At = pep->A;
    583:   if (matctx->subc) A = matctx->A;
    584:   else A = At;
    585:   /* Form the explicit system matrix */
    586:   DHii = T12;
    587:   PetscMemzero(DHii,k*k*nmat*sizeof(PetscScalar));
    588:   for (i=0;i<k;i++) DHii[k+i+i*lda] = 1.0/a[0];
    589:   for (d=2;d<nmat;d++) {
    590:     for (j=0;j<k;j++) {
    591:       for (i=0;i<k;i++) {
    592:         DHii[d*k+i+j*lda] = ((h-b[d-1])*DHii[(d-1)*k+i+j*lda]+fH[(d-1)*k+i+j*lda]-g[d-1]*DHii[(d-2)*k+i+j*lda])/a[d-1];
    593:       }
    594:     }
    595:   }

    597:   /* T11 */
    598:   if (!matctx->compM1) {
    599:     MatCopy(A[0],E[0],DIFFERENT_NONZERO_PATTERN);
    600:     PEPEvaluateBasis(pep,h,0,Ts,NULL);
    601:     for (j=1;j<nmat;j++) {
    602:       MatAXPY(E[0],Ts[j],A[j],str);
    603:     }
    604:   }
    605:   for (i=n0;i<m0;i++) {
    606:     MatGetRow(E[0],i,&ncols,&idxmc,&valsc);
    607:     idx = n+i-n0;
    608:     for (j=0;j<ncols;j++) {
    609:       idxg[j] = matctx->map0[idxmc[j]];
    610:     }
    611:     MatSetValues(M,1,&idx,ncols,idxg,valsc,INSERT_VALUES);
    612:     MatRestoreRow(E[0],i,&ncols,&idxmc,&valsc);
    613:   }

    615:   /* T22 */
    616:   PetscBLASIntCast(lds,&lds_);
    617:   PetscBLASIntCast(k,&k_);
    618:   PetscBLASIntCast(lda,&lda_);
    619:   PetscStackCallBLAS("BLASgemm",BLASgemm_("C","N",&k_,&k_,&k_,&sone,S,&lds_,S,&lds_,&zero,Tr,&k_));
    620:   for (i=1;i<deg;i++) {
    621:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,Tr,&k_,DHii+i*k,&lda_,&zero,Ts,&k_));
    622:     s = (i==1)?0.0:1.0;
    623:     PetscStackCallBLAS("BLASgemm",BLASgemm_("C","N",&k_,&k_,&k_,&sone,fH+i*k,&lda_,Ts,&k_,&s,T22,&k_));
    624:   }
    625:   for (j=0;j<k;j++) idxp[j] = matctx->map1[j];
    626:   for (i=0;i<m1-n1;i++) {
    627:     idx = n+m0-n0+i;
    628:     for (j=0;j<k;j++) {
    629:       Tr[j] = T22[n1+i+j*k];
    630:     }
    631:     MatSetValues(M,1,&idx,k,idxp,Tr,INSERT_VALUES);
    632:   }

    634:   /* T21 */
    635:   for (i=1;i<deg;i++) {
    636:     s = (i==1)?0.0:1.0;
    637:     ss = PetscConj(fh[i]);
    638:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&ss,S,&lds_,fH+i*k,&lda_,&s,T21,&k_));
    639:   }
    640:   BVSetActiveColumns(W,0,k);
    641:   MatCreateSeqDense(PETSC_COMM_SELF,k,k,T21,&Mk);
    642:   BVMult(W,1.0,0.0,V,Mk);
    643:   for (i=0;i<k;i++) {
    644:     BVGetColumn(W,i,&vc);
    645:     VecConjugate(vc);
    646:     VecGetArrayRead(vc,&carray);
    647:     idx = matctx->map1[i];
    648:     MatSetValues(M,1,&idx,m0-n0,matctx->map0+n0,carray,INSERT_VALUES);
    649:     VecRestoreArrayRead(vc,&carray);
    650:     BVRestoreColumn(W,i,&vc);
    651:   }

    653:   /* T12 */
    654:   for (i=1;i<nmat;i++) {
    655:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,S,&lds_,DHii+i*k,&lda_,&zero,Ts,&k_));
    656:     for (j=0;j<k;j++) {
    657:       PetscMemcpy(T12+i*k+j*lda,Ts+j*k,k*sizeof(PetscScalar));
    658:     }
    659:   }
    660:   MatCreateSeqDense(PETSC_COMM_SELF,k,nmat-1,NULL,&Md);
    661:   for (i=0;i<nmat;i++) ts[i] = 1.0;
    662:   for (j=0;j<k;j++) {
    663:     MatDenseGetArray(Md,&array);
    664:     PetscMemcpy(array,T12+k+j*lda,(nmat-1)*k*sizeof(PetscScalar));
    665:     MatDenseRestoreArray(Md,&array);
    666:     BVSetActiveColumns(W,0,nmat-1);
    667:     BVMult(W,1.0,0.0,V,Md);
    668:     for (i=nmat-1;i>0;i--) {
    669:       BVGetColumn(W,i-1,&vc0);
    670:       BVGetColumn(W,i,&vc);
    671:       MatMult(A[i],vc0,vc);
    672:       BVRestoreColumn(W,i-1,&vc0);
    673:       BVRestoreColumn(W,i,&vc);
    674:     }
    675:     BVSetActiveColumns(W,1,nmat);
    676:     BVGetColumn(W,0,&vc0);
    677:     BVMultVec(W,1.0,0.0,vc0,ts);
    678:     VecGetArrayRead(vc0,&carray);
    679:     idx = matctx->map1[j];
    680:     MatSetValues(M,m0-n0,matctx->map0+n0,1,&idx,carray,INSERT_VALUES);
    681:     VecRestoreArrayRead(vc0,&carray);
    682:     BVRestoreColumn(W,0,&vc0);
    683:   }
    684:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
    685:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
    686:   KSPSetOperators(ksp,M,M);
    687:   KSPSetUp(ksp);
    688:   PetscFree(ts);
    689:   MatDestroy(&Mk);
    690:   MatDestroy(&Md);
    691:   if (flg) {
    692:     PetscFree(At);
    693:   }
    694:   PetscFree5(T22,T21,T12,Tr,Ts);
    695:   return(0);
    696: }

    698: static PetscErrorCode NRefSysSolve_explicit(PetscInt k,KSP ksp,Vec Rv,PetscScalar *Rh,Vec dVi,PetscScalar *dHi,MatExplicitCtx *matctx)
    699: {
    700:   PetscErrorCode    ierr;
    701:   PetscInt          n0,m0,n1,m1,i;
    702:   PetscScalar       *arrayV;
    703:   const PetscScalar *array;

    706:   MatGetOwnershipRange(matctx->E[1],&n1,&m1);
    707:   MatGetOwnershipRange(matctx->E[0],&n0,&m0);

    709:   /* Right side */
    710:   VecGetArrayRead(Rv,&array);
    711:   VecSetValues(matctx->tN,m0-n0,matctx->map0+n0,array,INSERT_VALUES);
    712:   VecRestoreArrayRead(Rv,&array);
    713:   VecSetValues(matctx->tN,m1-n1,matctx->map1+n1,Rh+n1,INSERT_VALUES);
    714:   VecAssemblyBegin(matctx->tN);
    715:   VecAssemblyEnd(matctx->tN);

    717:   /* Solve */
    718:   KSPSolve(ksp,matctx->tN,matctx->ttN);

    720:   /* Retrieve solution */
    721:   VecGetArray(dVi,&arrayV);
    722:   VecGetArrayRead(matctx->ttN,&array);
    723:   PetscMemcpy(arrayV,array,(m0-n0)*sizeof(PetscScalar));
    724:   VecRestoreArray(dVi,&arrayV);
    725:   if (!matctx->subc) {
    726:     VecGetArray(matctx->t1,&arrayV);
    727:     for (i=0;i<m1-n1;i++) arrayV[i] =  array[m0-n0+i];
    728:     VecRestoreArray(matctx->t1,&arrayV);
    729:     VecRestoreArrayRead(matctx->ttN,&array);
    730:     VecScatterBegin(matctx->scatterctx,matctx->t1,matctx->vseq,INSERT_VALUES,SCATTER_FORWARD);
    731:     VecScatterEnd(matctx->scatterctx,matctx->t1,matctx->vseq,INSERT_VALUES,SCATTER_FORWARD);
    732:     VecGetArrayRead(matctx->vseq,&array);
    733:     for (i=0;i<k;i++) dHi[i] = array[i];
    734:     VecRestoreArrayRead(matctx->vseq,&array);
    735:   }
    736:   return(0);
    737: }

    739: static PetscErrorCode NRefSysIter(PetscInt i,PEP pep,PetscInt k,KSP ksp,PetscScalar *fH,PetscScalar *S,PetscInt lds,PetscScalar *fh,PetscScalar *H,PetscInt ldh,Vec Rv,PetscScalar *Rh,BV V,Vec dVi,PetscScalar *dHi,MatExplicitCtx *matctx,BV W)
    740: {
    741:   PetscErrorCode    ierr;
    742:   PetscInt          j,m,lda=pep->nmat*k,n0,m0,idx;
    743:   PetscMPIInt       root,len;
    744:   PetscScalar       *array2,h;
    745:   const PetscScalar *array;
    746:   Vec               R,Vi;
    747:   FSubctx           *ctx;
    748:   Mat               M;

    751:   if (!matctx || !matctx->subc) {
    752:     for (j=0;j<pep->nmat;j++) fh[j] = fH[j*k+i+i*lda];
    753:     h   = H[i+i*ldh];
    754:     idx = i;
    755:     R   = Rv;
    756:     Vi  = dVi;
    757:     switch (pep->scheme) {
    758:     case PEP_REFINE_SCHEME_EXPLICIT:
    759:       NRefSysSetup_explicit(pep,k,ksp,fH,S,lds,fh,h,V,matctx,W);
    760:       matctx->compM1 = PETSC_FALSE;
    761:       break;
    762:     case PEP_REFINE_SCHEME_MBE:
    763:       NRefSysSetup_mbe(pep,k,ksp,fH,S,lds,fh,h,V,matctx);
    764:       matctx->compM1 = PETSC_FALSE;
    765:       break;
    766:     case PEP_REFINE_SCHEME_SCHUR:
    767:       KSPGetOperators(ksp,&M,NULL);
    768:       MatShellGetContext(M,&ctx);
    769:       NRefSysSetup_shell(pep,k,fH,S,lds,fh,h,ctx);
    770:       ctx->compM1 = PETSC_FALSE;
    771:       break;
    772:     }
    773:   } else {
    774:     if (i%matctx->subc->n==0 && (idx=i+matctx->subc->color)<k) {
    775:       for (j=0;j<pep->nmat;j++) fh[j] = fH[j*k+idx+idx*lda];
    776:       h = H[idx+idx*ldh];
    777:       matctx->idx = idx;
    778:       switch (pep->scheme) {
    779:       case PEP_REFINE_SCHEME_EXPLICIT:
    780:         NRefSysSetup_explicit(pep,k,ksp,fH,S,lds,fh,h,matctx->V,matctx,matctx->W);
    781:         matctx->compM1 = PETSC_FALSE;
    782:         break;
    783:       case PEP_REFINE_SCHEME_MBE:
    784:         NRefSysSetup_mbe(pep,k,ksp,fH,S,lds,fh,h,matctx->V,matctx);
    785:         matctx->compM1 = PETSC_FALSE;
    786:         break;
    787:       case PEP_REFINE_SCHEME_SCHUR:
    788:         break;
    789:       }
    790:     } else idx = matctx->idx;
    791:     VecScatterBegin(matctx->scatter_id[i%matctx->subc->n],Rv,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    792:     VecScatterEnd(matctx->scatter_id[i%matctx->subc->n],Rv,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    793:     VecGetArrayRead(matctx->tg,&array);
    794:     VecPlaceArray(matctx->t,array);
    795:     VecCopy(matctx->t,matctx->Rv);
    796:     VecResetArray(matctx->t);
    797:     VecRestoreArrayRead(matctx->tg,&array);
    798:     R  = matctx->Rv;
    799:     Vi = matctx->Vi;
    800:   }
    801:   if (idx==i && idx<k) {
    802:     switch (pep->scheme) {
    803:       case PEP_REFINE_SCHEME_EXPLICIT:
    804:         NRefSysSolve_explicit(k,ksp,R,Rh,Vi,dHi,matctx);
    805:         break;
    806:       case PEP_REFINE_SCHEME_MBE:
    807:         NRefSysSolve_mbe(k,k,matctx->W,matctx->w,matctx->Wt,matctx->wt,matctx->d,matctx->dt,ksp,matctx->M2,matctx->M3 ,matctx->M4,PETSC_FALSE,R,Rh,Vi,dHi,matctx->t);
    808:         break;
    809:       case PEP_REFINE_SCHEME_SCHUR:
    810:         NRefSysSolve_shell(ksp,pep->nmat,R,Rh,k,Vi,dHi);
    811:         break;
    812:     }
    813:   }
    814:   if (matctx && matctx->subc) {
    815:     VecGetLocalSize(Vi,&m);
    816:     VecGetArrayRead(Vi,&array);
    817:     VecGetArray(matctx->tg,&array2);
    818:     PetscMemcpy(array2,array,m*sizeof(PetscScalar));
    819:     VecRestoreArray(matctx->tg,&array2);
    820:     VecRestoreArrayRead(Vi,&array);
    821:     VecScatterBegin(matctx->scatter_id[i%matctx->subc->n],matctx->tg,dVi,INSERT_VALUES,SCATTER_REVERSE);
    822:     VecScatterEnd(matctx->scatter_id[i%matctx->subc->n],matctx->tg,dVi,INSERT_VALUES,SCATTER_REVERSE);
    823:     switch (pep->scheme) {
    824:     case PEP_REFINE_SCHEME_EXPLICIT:
    825:       MatGetOwnershipRange(matctx->E[0],&n0,&m0);
    826:       VecGetArrayRead(matctx->ttN,&array);
    827:       VecPlaceArray(matctx->tp,array+m0-n0);
    828:       VecScatterBegin(matctx->scatterp_id[i%matctx->subc->n],matctx->tp,matctx->tpg,INSERT_VALUES,SCATTER_FORWARD);
    829:       VecScatterEnd(matctx->scatterp_id[i%matctx->subc->n],matctx->tp,matctx->tpg,INSERT_VALUES,SCATTER_FORWARD);
    830:       VecResetArray(matctx->tp);
    831:       VecRestoreArrayRead(matctx->ttN,&array);
    832:       VecGetArrayRead(matctx->tpg,&array);
    833:       for (j=0;j<k;j++) dHi[j] = array[j];
    834:       VecRestoreArrayRead(matctx->tpg,&array);
    835:       break;
    836:      case PEP_REFINE_SCHEME_MBE:
    837:       root = 0;
    838:       for (j=0;j<i%matctx->subc->n;j++) root += matctx->subc->subsize[j];
    839:       PetscMPIIntCast(k,&len);
    840:       MPI_Bcast(dHi,len,MPIU_SCALAR,root,matctx->subc->dupparent);
    841:       break;
    842:     case PEP_REFINE_SCHEME_SCHUR:
    843:       break;
    844:     }
    845:   }
    846:   return(0);
    847: }

    849: static PetscErrorCode PEPNRefForwardSubstitution(PEP pep,PetscInt k,PetscScalar *S,PetscInt lds,PetscScalar *H,PetscInt ldh,PetscScalar *fH,BV dV,PetscScalar *dVS,PetscInt *rds,PetscScalar *dH,PetscInt lddh,KSP ksp,MatExplicitCtx *matctx)
    850: {
    852:   PetscInt       i,nmat=pep->nmat,lda=nmat*k;
    853:   PetscScalar    *fh,*Rh,*DfH;
    854:   PetscReal      norm;
    855:   BV             W;
    856:   Vec            Rv,t,dvi;
    857:   FSubctx        *ctx;
    858:   Mat            M,*At;
    859:   PetscBool      flg,lindep;

    862:   PetscMalloc2(nmat*k*k,&DfH,k,&Rh);
    863:   *rds = 0;
    864:   BVCreateVec(pep->V,&Rv);
    865:   switch (pep->scheme) {
    866:   case PEP_REFINE_SCHEME_EXPLICIT:
    867:     BVCreateVec(pep->V,&t);
    868:     BVDuplicateResize(pep->V,PetscMax(k,nmat),&W);
    869:     PetscMalloc1(nmat,&fh);
    870:     break;
    871:   case PEP_REFINE_SCHEME_MBE:
    872:     if (matctx->subc) {
    873:       BVCreateVec(pep->V,&t);
    874:       BVDuplicateResize(pep->V,PetscMax(k,nmat),&W);
    875:     } else {
    876:       W = matctx->W;
    877:       PetscObjectReference((PetscObject)W);
    878:       t = matctx->t;
    879:       PetscObjectReference((PetscObject)t);
    880:     }
    881:     BVScale(matctx->W,0.0);
    882:     BVScale(matctx->Wt,0.0);
    883:     BVScale(matctx->M2,0.0);
    884:     BVScale(matctx->M3,0.0);
    885:     PetscMalloc1(nmat,&fh);
    886:     break;
    887:   case PEP_REFINE_SCHEME_SCHUR:
    888:     KSPGetOperators(ksp,&M,NULL);
    889:     MatShellGetContext(M,&ctx);
    890:     BVCreateVec(pep->V,&t);
    891:     BVDuplicateResize(pep->V,PetscMax(k,nmat),&W);
    892:     fh = ctx->fih;
    893:     break;
    894:   }
    895:   PetscMemzero(dVS,2*k*k*sizeof(PetscScalar));
    896:   PetscMemzero(DfH,lda*k*sizeof(PetscScalar));
    897:   STGetTransform(pep->st,&flg);
    898:   if (flg) {
    899:     PetscMalloc1(pep->nmat,&At);
    900:     for (i=0;i<pep->nmat;i++) {
    901:       STGetMatrixTransformed(pep->st,i,&At[i]);
    902:     }
    903:   } else At = pep->A;

    905:   /* Main loop for computing the ith columns of dX and dS */
    906:   for (i=0;i<k;i++) {
    907:     /* Compute and update i-th column of the right hand side */
    908:     PetscMemzero(Rh,k*sizeof(PetscScalar));
    909:     NRefRightSide(nmat,pep->pbc,At,k,pep->V,S,lds,i,H,ldh,fH,DfH,dH,dV,dVS,*rds,Rv,Rh,W,t);

    911:     /* Update and solve system */
    912:     BVGetColumn(dV,i,&dvi);
    913:     NRefSysIter(i,pep,k,ksp,fH,S,lds,fh,H,ldh,Rv,Rh,pep->V,dvi,dH+i*k,matctx,W);
    914:     /* Orthogonalize computed solution */
    915:     BVOrthogonalizeVec(pep->V,dvi,dVS+i*2*k,&norm,&lindep);
    916:     BVRestoreColumn(dV,i,&dvi);
    917:     if (!lindep) {
    918:       BVOrthogonalizeColumn(dV,i,dVS+k+i*2*k,&norm,&lindep);
    919:       if (!lindep) {
    920:         dVS[k+i+i*2*k] = norm;
    921:         BVScaleColumn(dV,i,1.0/norm);
    922:         (*rds)++;
    923:       }
    924:     }
    925:   }
    926:   BVSetActiveColumns(dV,0,*rds);
    927:   VecDestroy(&t);
    928:   VecDestroy(&Rv);
    929:   BVDestroy(&W);
    930:   if (flg) {
    931:     PetscFree(At);
    932:   }
    933:   PetscFree2(DfH,Rh);
    934:   if (pep->scheme!=PEP_REFINE_SCHEME_SCHUR) { PetscFree(fh); }
    935:   return(0);
    936: }

    938: static PetscErrorCode NRefOrthogStep(PEP pep,PetscInt k,PetscScalar *H,PetscInt ldh,PetscScalar *fH,PetscScalar *S,PetscInt lds)
    939: {
    940: #if defined(PETSC_MISSING_LAPACK_GEQRF)
    942:   SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"GEQRF - Lapack routine is unavailable");
    943: #else
    945:   PetscInt       j,nmat=pep->nmat,deg=nmat-1,lda=nmat*k,ldg;
    946:   PetscScalar    *G,*tau,sone=1.0,zero=0.0,*work;
    947:   PetscBLASInt   lds_,k_,ldh_,info,ldg_,lda_;

    950:   PetscMalloc3(k,&tau,k,&work,deg*k*k,&G);
    951:   PetscBLASIntCast(lds,&lds_);
    952:   PetscBLASIntCast(lda,&lda_);
    953:   PetscBLASIntCast(k,&k_);

    955:   /* Form auxiliary matrix for the orthogonalization step */
    956:   ldg = deg*k;
    957:   PEPEvaluateBasisforMatrix(pep,nmat,k,H,ldh,fH);
    958:   PetscBLASIntCast(ldg,&ldg_);
    959:   PetscBLASIntCast(ldh,&ldh_);
    960:   for (j=0;j<deg;j++) {
    961:     PetscStackCallBLAS("BLASgemm",BLASgemm_("N","N",&k_,&k_,&k_,&sone,S,&lds_,fH+j*k,&lda_,&zero,G+j*k,&ldg_));
    962:   }
    963:   /* Orthogonalize and update S */
    964:   PetscStackCallBLAS("LAPACKgeqrf",LAPACKgeqrf_(&ldg_,&k_,G,&ldg_,tau,work,&k_,&info));
    965:   SlepcCheckLapackInfo("geqrf",info);
    966:   PetscStackCallBLAS("BLAStrsm",BLAStrsm_("R","U","N","N",&k_,&k_,&sone,G,&ldg_,S,&lds_));

    968:   /* Update H */
    969:   PetscStackCallBLAS("BLAStrmm",BLAStrmm_("L","U","N","N",&k_,&k_,&sone,G,&ldg_,H,&ldh_));
    970:   PetscStackCallBLAS("BLAStrsm",BLAStrsm_("R","U","N","N",&k_,&k_,&sone,G,&ldg_,H,&ldh_));
    971:   PetscFree3(tau,work,G);
    972:   return(0);
    973: #endif
    974: }

    976: static PetscErrorCode PEPNRefUpdateInvPair(PEP pep,PetscInt k,PetscScalar *H,PetscInt ldh,PetscScalar *fH,PetscScalar *dH,PetscScalar *S,PetscInt lds,BV dV,PetscScalar *dVS,PetscInt rds)
    977: {
    978: #if defined(PETSC_MISSING_LAPACK_GEQRF) || defined(PETSC_MISSING_LAPACK_ORGQR)
    980:   SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"GEQRF/ORGQR - Lapack routine is unavailable");
    981: #else
    983:   PetscInt       i,j,nmat=pep->nmat,lda=nmat*k;
    984:   PetscScalar    *tau,*array,*work;
    985:   PetscBLASInt   lds_,k_,lda_,ldh_,kdrs_,info,k2_;
    986:   Mat            M0;

    989:   PetscMalloc2(k,&tau,k,&work);
    990:   PetscBLASIntCast(lds,&lds_);
    991:   PetscBLASIntCast(lda,&lda_);
    992:   PetscBLASIntCast(ldh,&ldh_);
    993:   PetscBLASIntCast(k,&k_);
    994:   PetscBLASIntCast(2*k,&k2_);
    995:   PetscBLASIntCast((k+rds),&kdrs_);
    996:   /* Update H */
    997:   for (j=0;j<k;j++) {
    998:     for (i=0;i<k;i++) H[i+j*ldh] -= dH[i+j*k];
    999:   }
    1000:   /* Update V */
    1001:   for (j=0;j<k;j++) {
    1002:     for (i=0;i<k;i++) dVS[i+j*2*k] = -dVS[i+j*2*k]+S[i+j*lds];
    1003:     for (i=k;i<2*k;i++) dVS[i+j*2*k] = -dVS[i+j*2*k];
    1004:   }
    1005:   PetscStackCallBLAS("LAPACKgeqrf",LAPACKgeqrf_(&kdrs_,&k_,dVS,&k2_,tau,work,&k_,&info));
    1006:   SlepcCheckLapackInfo("geqrf",info);
    1007:   /* Copy triangular matrix in S */
    1008:   for (j=0;j<k;j++) {
    1009:     for (i=0;i<=j;i++) S[i+j*lds] = dVS[i+j*2*k];
    1010:     for (i=j+1;i<k;i++) S[i+j*lds] = 0.0;
    1011:   }
    1012:   PetscStackCallBLAS("LAPACKorgqr",LAPACKorgqr_(&k2_,&k_,&k_,dVS,&k2_,tau,work,&k_,&info));
    1013:   SlepcCheckLapackInfo("orgqr",info);
    1014:   MatCreateSeqDense(PETSC_COMM_SELF,k,k,NULL,&M0);
    1015:   MatDenseGetArray(M0,&array);
    1016:   for (j=0;j<k;j++) {
    1017:     PetscMemcpy(array+j*k,dVS+j*2*k,k*sizeof(PetscScalar));
    1018:   }
    1019:   MatDenseRestoreArray(M0,&array);
    1020:   BVMultInPlace(pep->V,M0,0,k);
    1021:   if (rds) {
    1022:     MatDenseGetArray(M0,&array);
    1023:     for (j=0;j<k;j++) {
    1024:       PetscMemcpy(array+j*k,dVS+k+j*2*k,rds*sizeof(PetscScalar));
    1025:     }
    1026:     MatDenseRestoreArray(M0,&array);
    1027:     BVMultInPlace(dV,M0,0,k);
    1028:     BVMult(pep->V,1.0,1.0,dV,NULL);
    1029:   }
    1030:   MatDestroy(&M0);
    1031:   NRefOrthogStep(pep,k,H,ldh,fH,S,lds);
    1032:   PetscFree2(tau,work);
    1033:   return(0);
    1034: #endif
    1035: }

    1037: static PetscErrorCode PEPNRefSetUp(PEP pep,PetscInt k,PetscScalar *H,PetscInt ldh,MatExplicitCtx *matctx,PetscBool ini)
    1038: {
    1039:   PetscErrorCode    ierr;
    1040:   FSubctx           *ctx;
    1041:   PetscScalar       t,*coef;
    1042:   const PetscScalar *array;
    1043:   MatStructure      str;
    1044:   PetscInt          j,nmat=pep->nmat,n0,m0,n1,m1,n0_,m0_,n1_,m1_,N0,N1,p,*idx1,*idx2,count,si,i,l0;
    1045:   MPI_Comm          comm;
    1046:   PetscMPIInt       np;
    1047:   const PetscInt    *rgs0,*rgs1;
    1048:   Mat               B,C,*E,*A,*At;
    1049:   IS                is1,is2;
    1050:   Vec               v;
    1051:   PetscBool         flg;
    1052:   Mat               M,P;

    1055:   PetscMalloc1(nmat,&coef);
    1056:   STGetTransform(pep->st,&flg);
    1057:   if (flg) {
    1058:     PetscMalloc1(pep->nmat,&At);
    1059:     for (i=0;i<pep->nmat;i++) {
    1060:       STGetMatrixTransformed(pep->st,i,&At[i]);
    1061:     }
    1062:   } else At = pep->A;
    1063:   switch (pep->scheme) {
    1064:   case PEP_REFINE_SCHEME_EXPLICIT:
    1065:     if (ini) {
    1066:       if (matctx->subc) {
    1067:         A = matctx->A;
    1068:         comm = PetscSubcommChild(matctx->subc);
    1069:       } else {
    1070:         A = At;
    1071:         PetscObjectGetComm((PetscObject)pep,&comm);
    1072:       }
    1073:       E = matctx->E;
    1074:       STGetMatStructure(pep->st,&str);
    1075:       MatDuplicate(A[0],MAT_COPY_VALUES,&E[0]);
    1076:       j = (matctx->subc)?matctx->subc->color:0;
    1077:       PEPEvaluateBasis(pep,H[j+j*ldh],0,coef,NULL);
    1078:       for (j=1;j<nmat;j++) {
    1079:         MatAXPY(E[0],coef[j],A[j],str);
    1080:       }
    1081:       MatCreateDense(comm,PETSC_DECIDE,PETSC_DECIDE,k,k,NULL,&E[1]);
    1082:       MatAssemblyBegin(E[1],MAT_FINAL_ASSEMBLY);
    1083:       MatAssemblyEnd(E[1],MAT_FINAL_ASSEMBLY);
    1084:       MatGetOwnershipRange(E[0],&n0,&m0);
    1085:       MatGetOwnershipRange(E[1],&n1,&m1);
    1086:       MatGetOwnershipRangeColumn(E[0],&n0_,&m0_);
    1087:       MatGetOwnershipRangeColumn(E[1],&n1_,&m1_);
    1088:       /* T12 and T21 are computed from V and V*, so,
    1089:          they must have the same column and row ranges */
    1090:       if (m0_-n0_ != m0-n0) SETERRQ(PETSC_COMM_SELF,1,"Inconsistent dimensions");
    1091:       MatCreateDense(comm,m0-n0,m1_-n1_,PETSC_DECIDE,PETSC_DECIDE,NULL,&B);
    1092:       MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
    1093:       MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
    1094:       MatCreateDense(comm,m1-n1,m0_-n0_,PETSC_DECIDE,PETSC_DECIDE,NULL,&C);
    1095:       MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
    1096:       MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
    1097:       MatCreateTile(1.0,E[0],1.0,B,1.0,C,1.0,E[1],&M);
    1098:       MatDestroy(&B);
    1099:       MatDestroy(&C);
    1100:       matctx->compM1 = PETSC_TRUE;
    1101:       MatGetSize(E[0],NULL,&N0);
    1102:       MatGetSize(E[1],NULL,&N1);
    1103:       MPI_Comm_size(PetscObjectComm((PetscObject)M),&np);
    1104:       MatGetOwnershipRanges(E[0],&rgs0);
    1105:       MatGetOwnershipRanges(E[1],&rgs1);
    1106:       PetscMalloc4(PetscMax(k,N1),&matctx->idxp,N0,&matctx->idxg,N0,&matctx->map0,N1,&matctx->map1);
    1107:       /* Create column (and row) mapping */
    1108:       for (p=0;p<np;p++) {
    1109:         for (j=rgs0[p];j<rgs0[p+1];j++) matctx->map0[j] = j+rgs1[p];
    1110:         for (j=rgs1[p];j<rgs1[p+1];j++) matctx->map1[j] = j+rgs0[p+1];
    1111:       }
    1112:       MatCreateVecs(M,NULL,&matctx->tN);
    1113:       MatCreateVecs(matctx->E[1],NULL,&matctx->t1);
    1114:       VecDuplicate(matctx->tN,&matctx->ttN);
    1115:       if (matctx->subc) {
    1116:         MPI_Comm_size(PetscObjectComm((PetscObject)pep),&np);
    1117:         count = np*k;
    1118:         PetscMalloc2(count,&idx1,count,&idx2);
    1119:         VecCreateMPI(PetscObjectComm((PetscObject)pep),m1-n1,PETSC_DECIDE,&matctx->tp);
    1120:         VecGetOwnershipRange(matctx->tp,&l0,NULL);
    1121:         VecCreateMPI(PetscObjectComm((PetscObject)pep),k,PETSC_DECIDE,&matctx->tpg);
    1122:         for (si=0;si<matctx->subc->n;si++) {
    1123:           if (matctx->subc->color==si) {
    1124:             j=0;
    1125:             if (matctx->subc->color==si) {
    1126:               for (p=0;p<np;p++) {
    1127:                 for (i=n1;i<m1;i++) {
    1128:                   idx1[j] = l0+i-n1;
    1129:                   idx2[j++] =p*k+i;
    1130:                 }
    1131:               }
    1132:             }
    1133:             count = np*(m1-n1);
    1134:           } else count =0;
    1135:           ISCreateGeneral(PetscObjectComm((PetscObject)pep),count,idx1,PETSC_COPY_VALUES,&is1);
    1136:           ISCreateGeneral(PetscObjectComm((PetscObject)pep),count,idx2,PETSC_COPY_VALUES,&is2);
    1137:           VecScatterCreate(matctx->tp,is1,matctx->tpg,is2,&matctx->scatterp_id[si]);
    1138:           ISDestroy(&is1);
    1139:           ISDestroy(&is2);
    1140:         }
    1141:         PetscFree2(idx1,idx2);
    1142:       } else {
    1143:         VecScatterCreateToAll(matctx->t1,&matctx->scatterctx,&matctx->vseq);
    1144:       }
    1145:       P = M;
    1146:     } else {
    1147:       if (matctx->subc) {
    1148:         /* Scatter vectors pep->V */
    1149:         for (i=0;i<k;i++) {
    1150:           BVGetColumn(pep->V,i,&v);
    1151:           VecScatterBegin(matctx->scatter_sub,v,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    1152:           VecScatterEnd(matctx->scatter_sub,v,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    1153:           BVRestoreColumn(pep->V,i,&v);
    1154:           VecGetArrayRead(matctx->tg,&array);
    1155:           VecPlaceArray(matctx->t,(const PetscScalar*)array);
    1156:           BVInsertVec(matctx->V,i,matctx->t);
    1157:           VecResetArray(matctx->t);
    1158:           VecRestoreArrayRead(matctx->tg,&array);
    1159:         }
    1160:       }
    1161:     }
    1162:     break;
    1163:   case PEP_REFINE_SCHEME_MBE:
    1164:     if (ini) {
    1165:       if (matctx->subc) {
    1166:         A = matctx->A;
    1167:         comm = PetscSubcommChild(matctx->subc);
    1168:       } else {
    1169:         matctx->V = pep->V;
    1170:         A = At;
    1171:         PetscObjectGetComm((PetscObject)pep,&comm);
    1172:         MatCreateVecs(pep->A[0],&matctx->t,NULL);
    1173:       }
    1174:       STGetMatStructure(pep->st,&str);
    1175:       MatDuplicate(A[0],MAT_COPY_VALUES,&matctx->M1);
    1176:       j = (matctx->subc)?matctx->subc->color:0;
    1177:       PEPEvaluateBasis(pep,H[j+j*ldh],0,coef,NULL);
    1178:       for (j=1;j<nmat;j++) {
    1179:         MatAXPY(matctx->M1,coef[j],A[j],str);
    1180:       }
    1181:       BVDuplicateResize(matctx->V,PetscMax(k,pep->nmat),&matctx->W);
    1182:       BVDuplicateResize(matctx->V,k,&matctx->M2);
    1183:       BVDuplicate(matctx->M2,&matctx->M3);
    1184:       BVDuplicate(matctx->M2,&matctx->Wt);
    1185:       PetscMalloc5(k*k,&matctx->M4,k*k,&matctx->w,k*k,&matctx->wt,k,&matctx->d,k,&matctx->dt);
    1186:       matctx->compM1 = PETSC_TRUE;
    1187:       M = matctx->M1;
    1188:       P = M;
    1189:     }
    1190:     break;
    1191:   case PEP_REFINE_SCHEME_SCHUR:
    1192:     if (ini) {
    1193:       PetscObjectGetComm((PetscObject)pep,&comm);
    1194:       MatGetSize(At[0],&m0,&n0);
    1195:       PetscMalloc1(1,&ctx);
    1196:       STGetMatStructure(pep->st,&str);
    1197:       /* Create a shell matrix to solve the linear system */
    1198:       ctx->V = pep->V;
    1199:       ctx->k = k; ctx->nmat = nmat;
    1200:       PetscMalloc5(nmat,&ctx->A,k*k,&ctx->M4,k,&ctx->pM4,2*k*k,&ctx->work,nmat,&ctx->fih);
    1201:       for (i=0;i<nmat;i++) ctx->A[i] = At[i];
    1202:       PetscMemzero(ctx->M4,k*k*sizeof(PetscScalar));
    1203:       MatCreateShell(comm,PETSC_DECIDE,PETSC_DECIDE,m0,n0,ctx,&M);
    1204:       MatShellSetOperation(M,MATOP_MULT,(void(*)(void))MatFSMult);
    1205:       BVDuplicateResize(ctx->V,PetscMax(k,pep->nmat),&ctx->W);
    1206:       BVDuplicateResize(ctx->V,k,&ctx->M2);
    1207:       BVDuplicate(ctx->M2,&ctx->M3);
    1208:       BVCreateVec(pep->V,&ctx->t);
    1209:       MatDuplicate(At[0],MAT_COPY_VALUES,&ctx->M1);
    1210:       PEPEvaluateBasis(pep,H[0],0,coef,NULL);
    1211:       for (j=1;j<nmat;j++) {
    1212:         MatAXPY(ctx->M1,coef[j],At[j],str);
    1213:       }
    1214:       MatDuplicate(At[0],MAT_COPY_VALUES,&P);
    1215:       /* Compute a precond matrix for the system */
    1216:       t = H[0];
    1217:       PEPEvaluateBasis(pep,t,0,coef,NULL);
    1218:       for (j=1;j<nmat;j++) {
    1219:         MatAXPY(P,coef[j],At[j],str);
    1220:       }
    1221:       ctx->compM1 = PETSC_TRUE;
    1222:     }
    1223:     break;
    1224:   }
    1225:   if (ini) {
    1226:     PEPRefineGetKSP(pep,&pep->refineksp);
    1227:     KSPSetErrorIfNotConverged(pep->refineksp,PETSC_TRUE);
    1228:     KSPSetOperators(pep->refineksp,M,P);
    1229:     KSPSetFromOptions(pep->refineksp);
    1230:   }

    1232:   if (!ini && matctx && matctx->subc) {
    1233:      /* Scatter vectors pep->V */
    1234:     for (i=0;i<k;i++) {
    1235:       BVGetColumn(pep->V,i,&v);
    1236:       VecScatterBegin(matctx->scatter_sub,v,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    1237:       VecScatterEnd(matctx->scatter_sub,v,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    1238:       BVRestoreColumn(pep->V,i,&v);
    1239:       VecGetArrayRead(matctx->tg,&array);
    1240:       VecPlaceArray(matctx->t,(const PetscScalar*)array);
    1241:       BVInsertVec(matctx->V,i,matctx->t);
    1242:       VecResetArray(matctx->t);
    1243:       VecRestoreArrayRead(matctx->tg,&array);
    1244:     }
    1245:    }
    1246:   PetscFree(coef);
    1247:   if (flg) {
    1248:     PetscFree(At);
    1249:   }
    1250:   return(0);
    1251: }

    1253: static PetscErrorCode NRefSubcommSetup(PEP pep,PetscInt k,MatExplicitCtx *matctx,PetscInt nsubc)
    1254: {
    1255:   PetscErrorCode    ierr;
    1256:   PetscInt          i,si,j,m0,n0,nloc0,nloc_sub,*idx1,*idx2;
    1257:   IS                is1,is2;
    1258:   BVType            type;
    1259:   Vec               v;
    1260:   const PetscScalar *array;
    1261:   Mat               *A;
    1262:   PetscBool         flg;

    1265:   STGetTransform(pep->st,&flg);
    1266:   if (flg) {
    1267:     PetscMalloc1(pep->nmat,&A);
    1268:     for (i=0;i<pep->nmat;i++) {
    1269:       STGetMatrixTransformed(pep->st,i,&A[i]);
    1270:     }
    1271:   } else A = pep->A;

    1273:   /* Duplicate pep matrices */
    1274:   PetscMalloc3(pep->nmat,&matctx->A,nsubc,&matctx->scatter_id,nsubc,&matctx->scatterp_id);
    1275:   for (i=0;i<pep->nmat;i++) {
    1276:     MatCreateRedundantMatrix(A[i],0,PetscSubcommChild(matctx->subc),MAT_INITIAL_MATRIX,&matctx->A[i]);
    1277:   }

    1279:   /* Create Scatter */
    1280:   MatCreateVecs(matctx->A[0],&matctx->t,NULL);
    1281:   MatGetLocalSize(matctx->A[0],&nloc_sub,NULL);
    1282:   VecCreateMPI(PetscSubcommContiguousParent(matctx->subc),nloc_sub,PETSC_DECIDE,&matctx->tg);
    1283:   BVGetColumn(pep->V,0,&v);
    1284:   VecGetOwnershipRange(v,&n0,&m0);
    1285:   nloc0 = m0-n0;
    1286:   PetscMalloc2(matctx->subc->n*nloc0,&idx1,matctx->subc->n*nloc0,&idx2);
    1287:   j = 0;
    1288:   for (si=0;si<matctx->subc->n;si++) {
    1289:     for (i=n0;i<m0;i++) {
    1290:       idx1[j]   = i;
    1291:       idx2[j++] = i+pep->n*si;
    1292:     }
    1293:   }
    1294:   ISCreateGeneral(PetscObjectComm((PetscObject)pep),matctx->subc->n*nloc0,idx1,PETSC_COPY_VALUES,&is1);
    1295:   ISCreateGeneral(PetscObjectComm((PetscObject)pep),matctx->subc->n*nloc0,idx2,PETSC_COPY_VALUES,&is2);
    1296:   VecScatterCreate(v,is1,matctx->tg,is2,&matctx->scatter_sub);
    1297:   ISDestroy(&is1);
    1298:   ISDestroy(&is2);
    1299:   for (si=0;si<matctx->subc->n;si++) {
    1300:     j=0;
    1301:     for (i=n0;i<m0;i++) {
    1302:       idx1[j] = i;
    1303:       idx2[j++] = i+pep->n*si;
    1304:     }
    1305:     ISCreateGeneral(PetscObjectComm((PetscObject)pep),nloc0,idx1,PETSC_COPY_VALUES,&is1);
    1306:     ISCreateGeneral(PetscObjectComm((PetscObject)pep),nloc0,idx2,PETSC_COPY_VALUES,&is2);
    1307:     VecScatterCreate(v,is1,matctx->tg,is2,&matctx->scatter_id[si]);
    1308:     ISDestroy(&is1);
    1309:     ISDestroy(&is2);
    1310:   }
    1311:   BVRestoreColumn(pep->V,0,&v);
    1312:   PetscFree2(idx1,idx2);

    1314:   /* Duplicate pep->V vecs */
    1315:   BVGetType(pep->V,&type);
    1316:   BVCreate(PetscSubcommChild(matctx->subc),&matctx->V);
    1317:   BVSetType(matctx->V,type);
    1318:   BVSetSizesFromVec(matctx->V,matctx->t,k);
    1319:   if (pep->scheme==PEP_REFINE_SCHEME_EXPLICIT) {
    1320:     BVDuplicateResize(matctx->V,PetscMax(k,pep->nmat),&matctx->W);
    1321:   }
    1322:   for (i=0;i<k;i++) {
    1323:     BVGetColumn(pep->V,i,&v);
    1324:     VecScatterBegin(matctx->scatter_sub,v,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    1325:     VecScatterEnd(matctx->scatter_sub,v,matctx->tg,INSERT_VALUES,SCATTER_FORWARD);
    1326:     BVRestoreColumn(pep->V,i,&v);
    1327:     VecGetArrayRead(matctx->tg,&array);
    1328:     VecPlaceArray(matctx->t,(const PetscScalar*)array);
    1329:     BVInsertVec(matctx->V,i,matctx->t);
    1330:     VecResetArray(matctx->t);
    1331:     VecRestoreArrayRead(matctx->tg,&array);
    1332:   }

    1334:   VecDuplicate(matctx->t,&matctx->Rv);
    1335:   VecDuplicate(matctx->t,&matctx->Vi);
    1336:   if (flg) {
    1337:     PetscFree(A);
    1338:   }
    1339:   return(0);
    1340: }

    1342: static PetscErrorCode NRefSubcommDestroy(PEP pep,MatExplicitCtx *matctx)
    1343: {
    1345:   PetscInt       i;

    1348:   VecScatterDestroy(&matctx->scatter_sub);
    1349:   for (i=0;i<matctx->subc->n;i++) {
    1350:     VecScatterDestroy(&matctx->scatter_id[i]);
    1351:   }
    1352:   for (i=0;i<pep->nmat;i++) {
    1353:     MatDestroy(&matctx->A[i]);
    1354:   }
    1355:   if (pep->scheme==PEP_REFINE_SCHEME_EXPLICIT) {
    1356:     for (i=0;i<matctx->subc->n;i++) {
    1357:       VecScatterDestroy(&matctx->scatterp_id[i]);
    1358:     }
    1359:     VecDestroy(&matctx->tp);
    1360:     VecDestroy(&matctx->tpg);
    1361:     BVDestroy(&matctx->W);
    1362:   }
    1363:   PetscFree3(matctx->A,matctx->scatter_id,matctx->scatterp_id);
    1364:   BVDestroy(&matctx->V);
    1365:   VecDestroy(&matctx->t);
    1366:   VecDestroy(&matctx->tg);
    1367:   VecDestroy(&matctx->Rv);
    1368:   VecDestroy(&matctx->Vi);
    1369:   return(0);
    1370: }

    1372: PetscErrorCode PEPNewtonRefinement_TOAR(PEP pep,PetscScalar sigma,PetscInt *maxits,PetscReal *tol,PetscInt k,PetscScalar *S,PetscInt lds)
    1373: {
    1374: #if defined(PETSC_MISSING_LAPACK_GETRF) || defined(PETSC_MISSING_LAPACK_GETRI)
    1376:   SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"GETRF/GETRI - Lapack routine is unavailable");
    1377: #else
    1379:   PetscScalar    *H,*work,*dH,*fH,*dVS;
    1380:   PetscInt       ldh,i,j,its=1,nmat=pep->nmat,nsubc=pep->npart,rds;
    1381:   PetscBLASInt   k_,ld_,*p,info;
    1382:   BV             dV;
    1383:   PetscBool      sinvert,flg;
    1384:   MatExplicitCtx *matctx=NULL;
    1385:   Vec            v;
    1386:   Mat            M,P;
    1387:   FSubctx        *ctx;

    1390:   PetscLogEventBegin(PEP_Refine,pep,0,0,0);
    1391:   if (k > pep->n) SETERRQ1(PetscObjectComm((PetscObject)pep),1,"Multiple Refinement available only for invariant pairs of dimension smaller than n=%D",pep->n);
    1392:   /* the input tolerance is not being taken into account (by the moment) */
    1393:   its = *maxits;
    1394:   PetscMalloc3(k*k,&dH,nmat*k*k,&fH,k,&work);
    1395:   DSGetLeadingDimension(pep->ds,&ldh);
    1396:   DSGetArray(pep->ds,DS_MAT_A,&H);
    1397:   DSRestoreArray(pep->ds,DS_MAT_A,&H);
    1398:   PetscMalloc1(2*k*k,&dVS);
    1399:   STGetTransform(pep->st,&flg);
    1400:   if (!flg && pep->st && pep->ops->backtransform) { /* BackTransform */
    1401:     PetscBLASIntCast(k,&k_);
    1402:     PetscBLASIntCast(ldh,&ld_);
    1403:     PetscObjectTypeCompare((PetscObject)pep->st,STSINVERT,&sinvert);
    1404:     if (sinvert) {
    1405:       DSGetArray(pep->ds,DS_MAT_A,&H);
    1406:       PetscMalloc1(k,&p);
    1407:       PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&k_,&k_,H,&ld_,p,&info));
    1408:       SlepcCheckLapackInfo("getrf",info);
    1409:       PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&k_,H,&ld_,p,work,&k_,&info));
    1410:       SlepcCheckLapackInfo("getri",info);
    1411:       DSRestoreArray(pep->ds,DS_MAT_A,&H);
    1412:       pep->ops->backtransform = NULL;
    1413:     }
    1414:     if (sigma!=0.0) {
    1415:       DSGetArray(pep->ds,DS_MAT_A,&H);
    1416:       for (i=0;i<k;i++) H[i+ldh*i] += sigma;
    1417:       DSRestoreArray(pep->ds,DS_MAT_A,&H);
    1418:       pep->ops->backtransform = NULL;
    1419:     }
    1420:   }
    1421:   if ((pep->scale==PEP_SCALE_BOTH || pep->scale==PEP_SCALE_SCALAR) && pep->sfactor!=1.0) {
    1422:     DSGetArray(pep->ds,DS_MAT_A,&H);
    1423:     for (j=0;j<k;j++) {
    1424:       for (i=0;i<k;i++) H[i+j*ldh] *= pep->sfactor;
    1425:     }
    1426:     DSRestoreArray(pep->ds,DS_MAT_A,&H);
    1427:     if (!flg) {
    1428:       /* Restore original values */
    1429:       for (i=0;i<pep->nmat;i++){
    1430:         pep->pbc[pep->nmat+i] *= pep->sfactor;
    1431:         pep->pbc[2*pep->nmat+i] *= pep->sfactor*pep->sfactor;
    1432:       }
    1433:     }
    1434:   }
    1435:   if ((pep->scale==PEP_SCALE_DIAGONAL || pep->scale==PEP_SCALE_BOTH) && pep->Dr) {
    1436:     for (i=0;i<k;i++) {
    1437:       BVGetColumn(pep->V,i,&v);
    1438:       VecPointwiseMult(v,v,pep->Dr);
    1439:       BVRestoreColumn(pep->V,i,&v);
    1440:     }
    1441:   }
    1442:   DSGetArray(pep->ds,DS_MAT_A,&H);

    1444:   NRefOrthogStep(pep,k,H,ldh,fH,S,lds);
    1445:   /* check if H is in Schur form */
    1446:   for (i=0;i<k-1;i++) {
    1447:     if (H[i+1+i*ldh]!=0.0) {
    1448: #if !defined(PETSC_USE_COMPLEX)
    1449:       SETERRQ(PetscObjectComm((PetscObject)pep),1,"Iterative Refinement requires the complex Schur form of the projected matrix");
    1450: #else
    1451:       SETERRQ(PetscObjectComm((PetscObject)pep),1,"Iterative Refinement requires an upper triangular projected matrix");
    1452: #endif
    1453:     }
    1454:   }
    1455:   if (nsubc>k) SETERRQ(PetscObjectComm((PetscObject)pep),1,"Amount of subcommunicators should not be larger than the invariant pair dimension");
    1456:   BVSetActiveColumns(pep->V,0,k);
    1457:   BVDuplicateResize(pep->V,k,&dV);
    1458:   PetscLogObjectParent((PetscObject)pep,(PetscObject)dV);
    1459:   if (pep->scheme!=PEP_REFINE_SCHEME_SCHUR) {
    1460:     PetscMalloc1(1,&matctx);
    1461:     if (nsubc>1) { /* spliting in subcommunicators */
    1462:       matctx->subc = pep->refinesubc;
    1463:       NRefSubcommSetup(pep,k,matctx,nsubc);
    1464:     } else matctx->subc=NULL;
    1465:   }

    1467:   /* Loop performing iterative refinements */
    1468:   for (i=0;i<its;i++) {
    1469:     /* Pre-compute the polynomial basis evaluated in H */
    1470:     PEPEvaluateBasisforMatrix(pep,nmat,k,H,ldh,fH);
    1471:     PEPNRefSetUp(pep,k,H,ldh,matctx,PetscNot(i));
    1472:     /* Solve the linear system */
    1473:     PEPNRefForwardSubstitution(pep,k,S,lds,H,ldh,fH,dV,dVS,&rds,dH,k,pep->refineksp,matctx);
    1474:     /* Update X (=V*S) and H, and orthogonalize [X;X*fH1;...;XfH(deg-1)] */
    1475:     PEPNRefUpdateInvPair(pep,k,H,ldh,fH,dH,S,lds,dV,dVS,rds);
    1476:   }
    1477:   DSRestoreArray(pep->ds,DS_MAT_A,&H);
    1478:   if (!flg && sinvert) {
    1479:     PetscFree(p);
    1480:   }
    1481:   PetscFree3(dH,fH,work);
    1482:   PetscFree(dVS);
    1483:   BVDestroy(&dV);
    1484:   switch (pep->scheme) {
    1485:   case PEP_REFINE_SCHEME_EXPLICIT:
    1486:     for (i=0;i<2;i++) {
    1487:       MatDestroy(&matctx->E[i]);
    1488:     }
    1489:     PetscFree4(matctx->idxp,matctx->idxg,matctx->map0,matctx->map1);
    1490:     VecDestroy(&matctx->tN);
    1491:     VecDestroy(&matctx->ttN);
    1492:     VecDestroy(&matctx->t1);
    1493:     if (nsubc>1) {
    1494:       NRefSubcommDestroy(pep,matctx);
    1495:     } else {
    1496:       VecDestroy(&matctx->vseq);
    1497:       VecScatterDestroy(&matctx->scatterctx);
    1498:     }
    1499:     PetscFree(matctx);
    1500:     KSPGetOperators(pep->refineksp,&M,NULL);
    1501:     MatDestroy(&M);
    1502:     break;
    1503:   case PEP_REFINE_SCHEME_MBE:
    1504:     BVDestroy(&matctx->W);
    1505:     BVDestroy(&matctx->Wt);
    1506:     BVDestroy(&matctx->M2);
    1507:     BVDestroy(&matctx->M3);
    1508:     MatDestroy(&matctx->M1);
    1509:     VecDestroy(&matctx->t);
    1510:     PetscFree5(matctx->M4,matctx->w,matctx->wt,matctx->d,matctx->dt);
    1511:     if (nsubc>1) {
    1512:       NRefSubcommDestroy(pep,matctx);
    1513:     }
    1514:     PetscFree(matctx);
    1515:     break;
    1516:   case PEP_REFINE_SCHEME_SCHUR:
    1517:     KSPGetOperators(pep->refineksp,&M,&P);
    1518:     MatShellGetContext(M,&ctx);
    1519:     PetscFree5(ctx->A,ctx->M4,ctx->pM4,ctx->work,ctx->fih);
    1520:     MatDestroy(&ctx->M1);
    1521:     BVDestroy(&ctx->M2);
    1522:     BVDestroy(&ctx->M3);
    1523:     BVDestroy(&ctx->W);
    1524:     VecDestroy(&ctx->t);
    1525:     PetscFree(ctx);
    1526:     MatDestroy(&M);
    1527:     MatDestroy(&P);
    1528:     break;
    1529:   }
    1530:   PetscLogEventEnd(PEP_Refine,pep,0,0,0);
    1531:   return(0);
    1532: #endif
    1533: }