Actual source code: bvlapack.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:    BV private kernels that use the LAPACK
 12: */

 14: #include <slepc/private/bvimpl.h>
 15: #include <slepcblaslapack.h>

 17: /*
 18:     Reduction operation to compute sqrt(x**2+y**2) when normalizing vectors
 19: */
 20: SLEPC_EXTERN void MPIAPI SlepcPythag(void *in,void *inout,PetscMPIInt *len,MPI_Datatype *datatype)
 21: {
 22:   PetscBLASInt i,n=*len;
 23:   PetscReal    *x = (PetscReal*)in,*y = (PetscReal*)inout;

 25:   PetscFunctionBegin;
 26:   if (PetscUnlikely(*datatype!=MPIU_REAL)) {
 27:     (void)(*PetscErrorPrintf)("Only implemented for MPIU_REAL data type");
 28:     MPI_Abort(PETSC_COMM_WORLD,1);
 29:   }
 30:   for (i=0;i<n;i++) y[i] = SlepcAbs(x[i],y[i]);
 31:   PetscFunctionReturnVoid();
 32: }

 34: /*
 35:     Compute ||A|| for an mxn matrix
 36: */
 37: PetscErrorCode BVNorm_LAPACK_Private(BV bv,PetscInt m_,PetscInt n_,const PetscScalar *A,PetscInt lda_,NormType type,PetscReal *nrm,PetscBool mpi)
 38: {
 39:   PetscBLASInt   m,n,lda,i,j;
 40:   PetscMPIInt    len;
 41:   PetscReal      lnrm,*rwork=NULL,*rwork2=NULL;

 43:   PetscFunctionBegin;
 44:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
 45:   PetscCall(PetscBLASIntCast(m_,&m));
 46:   PetscCall(PetscBLASIntCast(n_,&n));
 47:   PetscCall(PetscBLASIntCast(lda_,&lda));
 48:   if (type==NORM_FROBENIUS || type==NORM_2) {
 49:     lnrm = LAPACKlange_("F",&m,&n,(PetscScalar*)A,&lda,rwork);
 50:     if (mpi) PetscCallMPI(MPIU_Allreduce(&lnrm,nrm,1,MPIU_REAL,MPIU_LAPY2,PetscObjectComm((PetscObject)bv)));
 51:     else *nrm = lnrm;
 52:     PetscCall(PetscLogFlops(2.0*m*n));
 53:   } else if (type==NORM_1) {
 54:     if (mpi) {
 55:       PetscCall(BVAllocateWork_Private(bv,2*n_));
 56:       rwork = (PetscReal*)bv->work;
 57:       rwork2 = rwork+n_;
 58:       PetscCall(PetscArrayzero(rwork,n_));
 59:       PetscCall(PetscArrayzero(rwork2,n_));
 60:       for (j=0;j<n_;j++) {
 61:         for (i=0;i<m_;i++) {
 62:           rwork[j] += PetscAbsScalar(A[i+j*lda_]);
 63:         }
 64:       }
 65:       PetscCall(PetscMPIIntCast(n_,&len));
 66:       PetscCallMPI(MPIU_Allreduce(rwork,rwork2,len,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)bv)));
 67:       *nrm = 0.0;
 68:       for (j=0;j<n_;j++) if (rwork2[j] > *nrm) *nrm = rwork2[j];
 69:     } else {
 70:       *nrm = LAPACKlange_("O",&m,&n,(PetscScalar*)A,&lda,rwork);
 71:     }
 72:     PetscCall(PetscLogFlops(1.0*m*n));
 73:   } else if (type==NORM_INFINITY) {
 74:     PetscCall(BVAllocateWork_Private(bv,m_));
 75:     rwork = (PetscReal*)bv->work;
 76:     lnrm = LAPACKlange_("I",&m,&n,(PetscScalar*)A,&lda,rwork);
 77:     if (mpi) PetscCallMPI(MPIU_Allreduce(&lnrm,nrm,1,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)bv)));
 78:     else *nrm = lnrm;
 79:     PetscCall(PetscLogFlops(1.0*m*n));
 80:   }
 81:   PetscCall(PetscFPTrapPop());
 82:   PetscFunctionReturn(PETSC_SUCCESS);
 83: }

 85: /*
 86:     Normalize the columns of an mxn matrix A
 87: */
 88: PetscErrorCode BVNormalize_LAPACK_Private(BV bv,PetscInt m_,PetscInt n_,const PetscScalar *A,PetscInt lda_,PetscScalar *eigi,PetscBool mpi)
 89: {
 90:   PetscBLASInt   m,lda,j,k,zero=0;
 91:   PetscMPIInt    len;
 92:   PetscReal      *norms,*rwork=NULL,*rwork2=NULL,done=1.0;

 94:   PetscFunctionBegin;
 95:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
 96:   PetscCall(PetscBLASIntCast(m_,&m));
 97:   PetscCall(PetscBLASIntCast(lda_,&lda));
 98:   PetscCall(BVAllocateWork_Private(bv,2*n_));
 99:   rwork = (PetscReal*)bv->work;
100:   rwork2 = rwork+n_;
101:   /* compute local norms */
102:   for (j=0;j<n_;j++) {
103:     k = 1;
104:     if (!PetscDefined(USE_COMPLEX) && eigi && eigi[j] != 0.0) k = 2;
105:     rwork[j] = LAPACKlange_("F",&m,&k,(PetscScalar*)(A+j*lda_),&lda,rwork2);
106:     if (k==2) { rwork[j+1] = rwork[j]; j++; }
107:   }
108:   /* reduction to get global norms */
109:   if (mpi) {
110:     PetscCall(PetscMPIIntCast(n_,&len));
111:     PetscCall(PetscArrayzero(rwork2,n_));
112:     PetscCallMPI(MPIU_Allreduce(rwork,rwork2,len,MPIU_REAL,MPIU_LAPY2,PetscObjectComm((PetscObject)bv)));
113:     norms = rwork2;
114:   } else norms = rwork;
115:   /* scale columns */
116:   for (j=0;j<n_;j++) {
117:     k = 1;
118: #if !PetscDefined(USE_COMPLEX)
119:     if (eigi && eigi[j] != 0.0) k = 2;
120: #endif
121:     PetscCallLAPACKInfo("LAPACKlascl",LAPACKlascl_("G",&zero,&zero,norms+j,&done,&m,&k,(PetscScalar*)(A+j*lda_),&lda,&info));
122:     if (k==2) j++;
123:   }
124:   PetscCall(PetscLogFlops(3.0*m*n_));
125:   PetscCall(PetscFPTrapPop());
126:   PetscFunctionReturn(PETSC_SUCCESS);
127: }

129: /*
130:    Compute the upper Cholesky factor in R and its inverse in S.
131:    If S == R then the inverse overwrites the Cholesky factor.
132:  */
133: PetscErrorCode BVMatCholInv_LAPACK_Private(BV bv,Mat R,Mat S)
134: {
135:   PetscInt       i,k,l,n,m,ld,lds;
136:   PetscScalar    *pR,*pS;
137:   PetscBLASInt   info,n_ = 0,m_ = 0,ld_,lds_;

139:   PetscFunctionBegin;
140:   l = bv->l;
141:   k = bv->k;
142:   PetscCall(MatGetSize(R,&m,NULL));
143:   n = k-l;
144:   PetscCall(PetscBLASIntCast(m,&m_));
145:   PetscCall(PetscBLASIntCast(n,&n_));
146:   ld  = m;
147:   ld_ = m_;
148:   PetscCall(MatDenseGetArray(R,&pR));

150:   if (S==R) {
151:     PetscCall(BVAllocateWork_Private(bv,m*k));
152:     pS = bv->work;
153:     lds = ld;
154:     lds_ = ld_;
155:   } else {
156:     PetscCall(MatDenseGetArray(S,&pS));
157:     PetscCall(MatGetSize(S,&lds,NULL));
158:     PetscCall(PetscBLASIntCast(lds,&lds_));
159:   }

161:   /* save a copy of matrix in S */
162:   for (i=l;i<k;i++) PetscCall(PetscArraycpy(pS+i*lds+l,pR+i*ld+l,n));

164:   /* compute upper Cholesky factor in R */
165:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
166:   PetscCallBLAS("LAPACKpotrf",LAPACKpotrf_("U",&n_,pR+l*ld+l,&ld_,&info));
167:   PetscCall(PetscLogFlops((1.0*n*n*n)/3.0));

169:   if (info) {  /* LAPACKpotrf failed, retry on diagonally perturbed matrix */
170:     for (i=l;i<k;i++) {
171:       PetscCall(PetscArraycpy(pR+i*ld+l,pS+i*lds+l,n));
172:       pR[i+i*ld] += 50.0*PETSC_MACHINE_EPSILON;
173:     }
174:     PetscCallLAPACKInfo("LAPACKpotrf",LAPACKpotrf_("U",&n_,pR+l*ld+l,&ld_,&info));
175:     PetscCall(PetscLogFlops((1.0*n*n*n)/3.0));
176:   }

178:   /* compute S = inv(R) */
179:   if (S==R) {
180:     PetscCallLAPACKInfo("LAPACKtrtri",LAPACKtrtri_("U","N",&n_,pR+l*ld+l,&ld_,&info));
181:   } else {
182:     PetscCall(PetscArrayzero(pS+l*lds,(k-l)*k));
183:     for (i=l;i<k;i++) PetscCall(PetscArraycpy(pS+i*lds+l,pR+i*ld+l,n));
184:     PetscCallLAPACKInfo("LAPACKtrtri",LAPACKtrtri_("U","N",&n_,pS+l*lds+l,&lds_,&info));
185:   }
186:   PetscCall(PetscFPTrapPop());
187:   PetscCall(PetscLogFlops(0.33*n*n*n));

189:   /* Zero out entries below the diagonal */
190:   for (i=l;i<k-1;i++) {
191:     PetscCall(PetscArrayzero(pR+i*ld+i+1,(k-i-1)));
192:     if (S!=R) PetscCall(PetscArrayzero(pS+i*lds+i+1,(k-i-1)));
193:   }
194:   PetscCall(MatDenseRestoreArray(R,&pR));
195:   if (S!=R) PetscCall(MatDenseRestoreArray(S,&pS));
196:   PetscFunctionReturn(PETSC_SUCCESS);
197: }

199: /*
200:    Compute the inverse of an upper triangular matrix R, store it in S.
201:    If S == R then the inverse overwrites R.
202:  */
203: PetscErrorCode BVMatTriInv_LAPACK_Private(BV bv,Mat R,Mat S)
204: {
205:   PetscInt       i,k,l,n,m,ld,lds;
206:   PetscScalar    *pR,*pS;
207:   PetscBLASInt   n_,m_ = 0,ld_,lds_;

209:   PetscFunctionBegin;
210:   l = bv->l;
211:   k = bv->k;
212:   PetscCall(MatGetSize(R,&m,NULL));
213:   n = k-l;
214:   PetscCall(PetscBLASIntCast(m,&m_));
215:   PetscCall(PetscBLASIntCast(n,&n_));
216:   ld  = m;
217:   ld_ = m_;
218:   PetscCall(MatDenseGetArray(R,&pR));

220:   if (S==R) {
221:     PetscCall(BVAllocateWork_Private(bv,m*k));
222:     pS = bv->work;
223:     lds = ld;
224:     lds_ = ld_;
225:   } else {
226:     PetscCall(MatDenseGetArray(S,&pS));
227:     PetscCall(MatGetSize(S,&lds,NULL));
228:     PetscCall(PetscBLASIntCast(lds,&lds_));
229:   }

231:   /* compute S = inv(R) */
232:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
233:   if (S==R) {
234:     PetscCallLAPACKInfo("LAPACKtrtri",LAPACKtrtri_("U","N",&n_,pR+l*ld+l,&ld_,&info));
235:   } else {
236:     PetscCall(PetscArrayzero(pS+l*lds,(k-l)*k));
237:     for (i=l;i<k;i++) PetscCall(PetscArraycpy(pS+i*lds+l,pR+i*ld+l,n));
238:     PetscCallLAPACKInfo("LAPACKtrtri",LAPACKtrtri_("U","N",&n_,pS+l*lds+l,&lds_,&info));
239:   }
240:   PetscCall(PetscFPTrapPop());
241:   PetscCall(PetscLogFlops(0.33*n*n*n));

243:   PetscCall(MatDenseRestoreArray(R,&pR));
244:   if (S!=R) PetscCall(MatDenseRestoreArray(S,&pS));
245:   PetscFunctionReturn(PETSC_SUCCESS);
246: }

248: /*
249:    Compute the matrix to be used for post-multiplying the basis in the SVQB
250:    block orthogonalization method.
251:    On input R = V'*V, on output S = D*U*Lambda^{-1/2} where (U,Lambda) is
252:    the eigendecomposition of D*R*D with D=diag(R)^{-1/2}.
253:    If S == R then the result overwrites R.
254:  */
255: PetscErrorCode BVMatSVQB_LAPACK_Private(BV bv,Mat R,Mat S)
256: {
257:   PetscInt       i,j,k,l,n,m,ld,lds;
258:   PetscScalar    *pR,*pS,*D,*work,a;
259:   PetscReal      *eig,dummy;
260:   PetscBLASInt   lwork,n_,m_ = 0,ld_,lds_;
261: #if PetscDefined(USE_COMPLEX)
262:   PetscReal      *rwork,rdummy;
263: #endif

265:   PetscFunctionBegin;
266:   l = bv->l;
267:   k = bv->k;
268:   PetscCall(MatGetSize(R,&m,NULL));
269:   PetscCall(MatDenseGetLDA(R,&ld));
270:   n = k-l;
271:   PetscCall(PetscBLASIntCast(m,&m_));
272:   PetscCall(PetscBLASIntCast(n,&n_));
273:   ld_ = m_;
274:   PetscCall(MatDenseGetArray(R,&pR));

276:   if (S==R) {
277:     pS = pR;
278:     lds = ld;
279:     lds_ = ld_;
280:   } else {
281:     PetscCall(MatDenseGetArray(S,&pS));
282:     PetscCall(MatDenseGetLDA(S,&lds));
283:     PetscCall(PetscBLASIntCast(lds,&lds_));
284:   }
285:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));

287:   /* workspace query and memory allocation */
288:   lwork = -1;
289: #if PetscDefined(USE_COMPLEX)
290:   PetscCallLAPACKInfo("LAPACKsyev",LAPACKsyev_("V","L",&n_,pS,&lds_,&dummy,&a,&lwork,&rdummy,&info));
291:   PetscCall(PetscBLASIntCast((PetscInt)PetscRealPart(a),&lwork));
292:   PetscCall(PetscMalloc4(n,&eig,n,&D,lwork,&work,PetscMax(1,3*n-2),&rwork));
293: #else
294:   PetscCallLAPACKInfo("LAPACKsyev",LAPACKsyev_("V","L",&n_,pS,&lds_,&dummy,&a,&lwork,&info));
295:   PetscCall(PetscBLASIntCast((PetscInt)a,&lwork));
296:   PetscCall(PetscMalloc3(n,&eig,n,&D,lwork,&work));
297: #endif

299:   /* copy and scale matrix */
300:   for (i=l;i<k;i++) D[i-l] = 1.0/PetscSqrtReal(PetscRealPart(pR[i+i*ld]));
301:   for (i=l;i<k;i++) for (j=l;j<k;j++) pS[i+j*lds] = pR[i+j*ld]*D[i-l];
302:   for (j=l;j<k;j++) for (i=l;i<k;i++) pS[i+j*lds] *= D[j-l];

304:   /* compute eigendecomposition */
305: #if PetscDefined(USE_COMPLEX)
306:   PetscCallLAPACKInfo("LAPACKsyev",LAPACKsyev_("V","L",&n_,pS+l*lds+l,&lds_,eig,work,&lwork,rwork,&info));
307: #else
308:   PetscCallLAPACKInfo("LAPACKsyev",LAPACKsyev_("V","L",&n_,pS+l*lds+l,&lds_,eig,work,&lwork,&info));
309: #endif

311:   if (S!=R) {   /* R = U' */
312:     for (i=l;i<k;i++) for (j=l;j<k;j++) pR[i+j*ld] = pS[j+i*lds];
313:   }

315:   /* compute S = D*U*Lambda^{-1/2} */
316:   for (i=l;i<k;i++) for (j=l;j<k;j++) pS[i+j*lds] *= D[i-l];
317:   for (j=l;j<k;j++) for (i=l;i<k;i++) pS[i+j*lds] /= PetscSqrtReal(eig[j-l]);

319:   if (S!=R) {   /* compute R = inv(S) = Lambda^{1/2}*U'/D */
320:     for (i=l;i<k;i++) for (j=l;j<k;j++) pR[i+j*ld] *= PetscSqrtReal(eig[i-l]);
321:     for (j=l;j<k;j++) for (i=l;i<k;i++) pR[i+j*ld] /= D[j-l];
322:   }

324: #if PetscDefined(USE_COMPLEX)
325:   PetscCall(PetscFree4(eig,D,work,rwork));
326: #else
327:   PetscCall(PetscFree3(eig,D,work));
328: #endif
329:   PetscCall(PetscLogFlops(9.0*n*n*n));
330:   PetscCall(PetscFPTrapPop());

332:   PetscCall(MatDenseRestoreArray(R,&pR));
333:   if (S!=R) PetscCall(MatDenseRestoreArray(S,&pS));
334:   PetscFunctionReturn(PETSC_SUCCESS);
335: }

337: /*
338:     QR factorization of an mxn matrix via parallel TSQR
339: */
340: PetscErrorCode BVOrthogonalize_LAPACK_TSQR(BV bv,PetscInt m_,PetscInt n_,PetscScalar *Q,PetscInt ldq_,PetscScalar *R,PetscInt ldr)
341: {
342:   PetscInt       level,plevel,nlevels,lda,worklen;
343:   PetscBLASInt   m,n,ldq,i,j,k,l,nb,sz,lwork;
344:   PetscScalar    *tau,*work,*A=NULL,*QQ=NULL,*Qhalf,*C=NULL,one=1.0,zero=0.0;
345:   PetscMPIInt    rank,size,count,stride,powtwo,s = 0;
346:   MPI_Datatype   tmat;

348:   PetscFunctionBegin;
349:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
350:   PetscCall(PetscBLASIntCast(m_,&m));
351:   PetscCall(PetscBLASIntCast(n_,&n));
352:   PetscCall(PetscBLASIntCast(ldq_,&ldq));
353:   k  = PetscMin(m,n);
354:   nb = 16;
355:   lda = 2*n;
356:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)bv),&size));
357:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)bv),&rank));
358:   nlevels = (PetscInt)PetscCeilReal(PetscLog2Real((PetscReal)size));
359:   PetscCall(PetscMPIIntCast(PetscPowInt(2,(PetscInt)PetscFloorReal(PetscLog2Real((PetscReal)size))),&powtwo));
360:   worklen = n+n*nb;
361:   if (nlevels) worklen += n*lda+n*lda*nlevels+n*lda;
362:   PetscCall(BVAllocateWork_Private(bv,worklen));
363:   tau  = bv->work;
364:   work = bv->work+n;
365:   PetscCall(PetscBLASIntCast(n*nb,&lwork));
366:   if (nlevels) {
367:     A  = bv->work+n+n*nb;
368:     QQ = bv->work+n+n*nb+n*lda;
369:     C  = bv->work+n+n*nb+n*lda+n*lda*nlevels;
370:   }

372:   /* Compute QR */
373:   PetscCallLAPACKInfo("LAPACKgeqrf",LAPACKgeqrf_(&m,&n,Q,&ldq,tau,work,&lwork,&info));

375:   /* Extract R */
376:   if (R || nlevels) {
377:     for (j=0;j<n;j++) {
378:       for (i=0;i<=PetscMin(j,m-1);i++) {
379:         if (nlevels) A[i+j*lda] = Q[i+j*ldq];
380:         else R[i+j*ldr] = Q[i+j*ldq];
381:       }
382:       for (i=PetscMin(j,m-1)+1;i<n;i++) {
383:         if (nlevels) A[i+j*lda] = 0.0;
384:         else R[i+j*ldr] = 0.0;
385:       }
386:     }
387:   }

389:   /* Compute orthogonal matrix in Q */
390:   PetscCallLAPACKInfo("LAPACKorgqr",LAPACKorgqr_(&m,&k,&k,Q,&ldq,tau,work,&lwork,&info));

392:   if (nlevels) {

394:     PetscCall(PetscMPIIntCast(n,&count));
395:     PetscCall(PetscMPIIntCast(lda,&stride));
396:     PetscCall(PetscBLASIntCast(lda,&l));
397:     PetscCallMPI(MPI_Type_vector(count,count,stride,MPIU_SCALAR,&tmat));
398:     PetscCallMPI(MPI_Type_commit(&tmat));

400:     for (level=nlevels;level>=1;level--) {

402:       plevel = PetscPowInt(2,level);
403:       PetscCall(PetscMPIIntCast(plevel*PetscFloorReal(rank/(PetscReal)plevel)+(rank+PetscPowInt(2,level-1))%plevel,&s));

405:       /* Stack triangular matrices */
406:       if (rank<s && s<size) {  /* send top part, receive bottom part */
407:         PetscCallMPI(MPI_Sendrecv(A,1,tmat,s,111,A+n,1,tmat,s,111,PetscObjectComm((PetscObject)bv),MPI_STATUS_IGNORE));
408:       } else if (s<size) {  /* copy top to bottom, receive top part */
409:         PetscCallMPI(MPI_Sendrecv(A,1,tmat,rank,111,A+n,1,tmat,rank,111,PetscObjectComm((PetscObject)bv),MPI_STATUS_IGNORE));
410:         PetscCallMPI(MPI_Sendrecv(A+n,1,tmat,s,111,A,1,tmat,s,111,PetscObjectComm((PetscObject)bv),MPI_STATUS_IGNORE));
411:       }
412:       if (level<nlevels && size!=powtwo) {  /* for cases when size is not a power of 2 */
413:         if (rank<size-powtwo) {  /* send bottom part */
414:           PetscCallMPI(MPI_Send(A+n,1,tmat,rank+powtwo,111,PetscObjectComm((PetscObject)bv)));
415:         } else if (rank>=powtwo) {  /* receive bottom part */
416:           PetscCallMPI(MPI_Recv(A+n,1,tmat,rank-powtwo,111,PetscObjectComm((PetscObject)bv),MPI_STATUS_IGNORE));
417:         }
418:       }
419:       /* Compute QR and build orthogonal matrix */
420:       if (level<nlevels || (level==nlevels && s<size)) {
421:         PetscCallLAPACKInfo("LAPACKgeqrf",LAPACKgeqrf_(&l,&n,A,&l,tau,work,&lwork,&info));
422:         PetscCall(PetscArraycpy(QQ+(level-1)*n*lda,A,n*lda));
423:         PetscCallLAPACKInfo("LAPACKorgqr",LAPACKorgqr_(&l,&n,&n,QQ+(level-1)*n*lda,&l,tau,work,&lwork,&info));
424:         for (j=0;j<n;j++) {
425:           for (i=j+1;i<n;i++) A[i+j*lda] = 0.0;
426:         }
427:       } else if (level==nlevels) {  /* only one triangular matrix, set Q=I */
428:         PetscCall(PetscArrayzero(QQ+(level-1)*n*lda,n*lda));
429:         for (j=0;j<n;j++) QQ[j+j*lda+(level-1)*n*lda] = 1.0;
430:       }
431:     }

433:     /* Extract R */
434:     if (R) {
435:       for (j=0;j<n;j++) {
436:         for (i=0;i<=j;i++) R[i+j*ldr] = A[i+j*lda];
437:         for (i=j+1;i<n;i++) R[i+j*ldr] = 0.0;
438:       }
439:     }

441:     /* Accumulate orthogonal matrices */
442:     for (level=1;level<=nlevels;level++) {
443:       plevel = PetscPowInt(2,level);
444:       PetscCall(PetscMPIIntCast(plevel*PetscFloorReal(rank/(PetscReal)plevel)+(rank+PetscPowInt(2,level-1))%plevel,&s));
445:       Qhalf = (rank<s)? QQ+(level-1)*n*lda: QQ+(level-1)*n*lda+n;
446:       if (level<nlevels) {
447:         PetscCallBLAS("BLASgemm",BLASgemm_("N","N",&l,&n,&n,&one,QQ+level*n*lda,&l,Qhalf,&l,&zero,C,&l));
448:         PetscCall(PetscArraycpy(QQ+level*n*lda,C,n*lda));
449:       } else {
450:         for (i=0;i<m/l;i++) {
451:           PetscCallBLAS("BLASgemm",BLASgemm_("N","N",&l,&n,&n,&one,Q+i*l,&ldq,Qhalf,&l,&zero,C,&l));
452:           for (j=0;j<n;j++) PetscCall(PetscArraycpy(Q+i*l+j*ldq,C+j*l,l));
453:         }
454:         sz = m%l;
455:         if (sz) {
456:           PetscCallBLAS("BLASgemm",BLASgemm_("N","N",&sz,&n,&n,&one,Q+(m/l)*l,&ldq,Qhalf,&l,&zero,C,&l));
457:           for (j=0;j<n;j++) PetscCall(PetscArraycpy(Q+(m/l)*l+j*ldq,C+j*l,sz));
458:         }
459:       }
460:     }

462:     PetscCallMPI(MPI_Type_free(&tmat));
463:   }

465:   PetscCall(PetscLogFlops(3.0*m*n*n));
466:   PetscCall(PetscFPTrapPop());
467:   PetscFunctionReturn(PETSC_SUCCESS);
468: }

470: /*
471:     Reduction operation to compute [~,Rout]=qr([Rin1;Rin2]) in the TSQR algorithm;
472:     all matrices are upper triangular stored in packed format
473: */
474: SLEPC_EXTERN void MPIAPI SlepcGivensPacked(void *in,void *inout,PetscMPIInt *len,MPI_Datatype *datatype)
475: {
476:   PetscBLASInt   n,i,j,k,one=1;
477:   PetscMPIInt    tsize;
478:   PetscScalar    v,s,*R2=(PetscScalar*)in,*R1=(PetscScalar*)inout;
479:   PetscReal      c;

481:   PetscFunctionBegin;
482:   PetscCallMPIAbort(PETSC_COMM_SELF,MPI_Type_size(*datatype,&tsize));  /* we assume len=1 */
483:   tsize /= sizeof(PetscScalar);
484:   n = (-1+(PetscBLASInt)PetscSqrtReal(1+8*tsize))/2;
485:   for (j=0;j<n;j++) {
486:     for (i=0;i<=j;i++) {
487:       LAPACKlartg_(R1+(2*n-j-1)*j/2+j,R2+(2*n-i-1)*i/2+j,&c,&s,&v);
488:       R1[(2*n-j-1)*j/2+j] = v;
489:       k = n-j-1;
490:       if (k) BLASrot_(&k,R1+(2*n-j-1)*j/2+j+1,&one,R2+(2*n-i-1)*i/2+j+1,&one,&c,&s);
491:     }
492:   }
493:   PetscFunctionReturnVoid();
494: }

496: /*
497:     Computes the R factor of the QR factorization of an mxn matrix via parallel TSQR
498: */
499: PetscErrorCode BVOrthogonalize_LAPACK_TSQR_OnlyR(BV bv,PetscInt m_,PetscInt n_,PetscScalar *Q,PetscInt ldq_,PetscScalar *R,PetscInt ldr)
500: {
501:   PetscInt       worklen;
502:   PetscBLASInt   m,n,ldq,i,j,s,nb,lwork;
503:   PetscScalar    *tau,*work,*A=NULL,*R1=NULL,*R2=NULL;
504:   PetscMPIInt    size,count;
505:   MPI_Datatype   tmat;

507:   PetscFunctionBegin;
508:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
509:   PetscCall(PetscBLASIntCast(m_,&m));
510:   PetscCall(PetscBLASIntCast(n_,&n));
511:   PetscCall(PetscBLASIntCast(ldq_,&ldq));
512:   nb = 16;
513:   s  = n+n*(n-1)/2;  /* length of packed triangular matrix */
514:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)bv),&size));
515:   worklen = n+n*nb+2*s+ldq*n;
516:   PetscCall(BVAllocateWork_Private(bv,worklen));
517:   tau  = bv->work;
518:   work = bv->work+n;
519:   R1   = bv->work+n+n*nb;
520:   R2   = bv->work+n+n*nb+s;
521:   A    = bv->work+n+n*nb+2*s;
522:   PetscCall(PetscBLASIntCast(n*nb,&lwork));
523:   PetscCall(PetscArraycpy(A,Q,ldq*n));

525:   /* Compute QR */
526:   PetscCallLAPACKInfo("LAPACKgeqrf",LAPACKgeqrf_(&m,&n,A,&ldq,tau,work,&lwork,&info));

528:   if (size==1) {
529:     /* Extract R */
530:     for (j=0;j<n;j++) {
531:       for (i=0;i<=PetscMin(j,m-1);i++) R[i+j*ldr] = A[i+j*ldq];
532:       for (i=PetscMin(j,m-1)+1;i<n;i++) R[i+j*ldr] = 0.0;
533:     }
534:   } else {
535:     /* Use MPI reduction operation to obtain global R */
536:     PetscCall(PetscMPIIntCast(s,&count));
537:     PetscCallMPI(MPI_Type_contiguous(count,MPIU_SCALAR,&tmat));
538:     PetscCallMPI(MPI_Type_commit(&tmat));
539:     for (i=0;i<n;i++) {
540:       for (j=i;j<n;j++) R1[(2*n-i-1)*i/2+j] = (i<m)?A[i+j*ldq]:0.0;
541:     }
542:     PetscCallMPI(MPIU_Allreduce(R1,R2,1,tmat,MPIU_TSQR,PetscObjectComm((PetscObject)bv)));
543:     for (i=0;i<n;i++) {
544:       for (j=0;j<i;j++) R[i+j*ldr] = 0.0;
545:       for (j=i;j<n;j++) R[i+j*ldr] = R2[(2*n-i-1)*i/2+j];
546:     }
547:     PetscCallMPI(MPI_Type_free(&tmat));
548:   }

550:   PetscCall(PetscLogFlops(3.0*m*n*n));
551:   PetscCall(PetscFPTrapPop());
552:   PetscFunctionReturn(PETSC_SUCCESS);
553: }