Actual source code: gmreig.c

petsc-3.6.4 2016-04-12
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  2: #include <../src/ksp/ksp/impls/gmres/gmresimpl.h>
  3: #include <petscblaslapack.h>

  7: PetscErrorCode KSPComputeExtremeSingularValues_GMRES(KSP ksp,PetscReal *emax,PetscReal *emin)
  8: {
  9: #if defined(PETSC_MISSING_LAPACK_GESVD)
 11:   /*
 12:       The Cray math libraries on T3D/T3E, and early versions of Intel Math Kernel Libraries (MKL)
 13:       for PCs do not seem to have the DGESVD() lapack routines
 14:   */
 15:   SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"GESVD - Lapack routine is unavailable\nNot able to provide singular value estimates.");
 16: #else
 17:   KSP_GMRES      *gmres = (KSP_GMRES*)ksp->data;
 19:   PetscInt       n = gmres->it + 1,i,N = gmres->max_k + 2;
 20:   PetscBLASInt   bn, bN,lwork, idummy,lierr;
 21:   PetscScalar    *R        = gmres->Rsvd,*work = R + N*N,sdummy;
 22:   PetscReal      *realpart = gmres->Dsvd;

 25:   PetscBLASIntCast(n,&bn);
 26:   PetscBLASIntCast(N,&bN);
 27:   PetscBLASIntCast(5*N,&lwork);
 28:   PetscBLASIntCast(N,&idummy);
 29:   if (n <= 0) {
 30:     *emax = *emin = 1.0;
 31:     return(0);
 32:   }
 33:   /* copy R matrix to work space */
 34:   PetscMemcpy(R,gmres->hh_origin,(gmres->max_k+2)*(gmres->max_k+1)*sizeof(PetscScalar));

 36:   /* zero below diagonal garbage */
 37:   for (i=0; i<n; i++) R[i*N+i+1] = 0.0;

 39:   /* compute Singular Values */
 40:   PetscFPTrapPush(PETSC_FP_TRAP_OFF);
 41: #if !defined(PETSC_USE_COMPLEX)
 42:   PetscStackCallBLAS("LAPACKgesvd",LAPACKgesvd_("N","N",&bn,&bn,R,&bN,realpart,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,&lierr));
 43: #else
 44:   PetscStackCallBLAS("LAPACKgesvd",LAPACKgesvd_("N","N",&bn,&bn,R,&bN,realpart,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,realpart+N,&lierr));
 45: #endif
 46:   if (lierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in SVD Lapack routine %d",(int)lierr);
 47:   PetscFPTrapPop();

 49:   *emin = realpart[n-1];
 50:   *emax = realpart[0];
 51: #endif
 52:   return(0);
 53: }

 55: /* ------------------------------------------------------------------------ */
 56: /* ESSL has a different calling sequence for dgeev() and zgeev() than standard LAPACK */
 59: PetscErrorCode KSPComputeEigenvalues_GMRES(KSP ksp,PetscInt nmax,PetscReal *r,PetscReal *c,PetscInt *neig)
 60: {
 61: #if defined(PETSC_HAVE_ESSL)
 62:   KSP_GMRES      *gmres = (KSP_GMRES*)ksp->data;
 64:   PetscInt       n = gmres->it + 1,N = gmres->max_k + 1;
 65:   PetscInt       i,*perm;
 66:   PetscScalar    *R     = gmres->Rsvd;
 67:   PetscScalar    *cwork = R + N*N,sdummy;
 68:   PetscReal      *work,*realpart = gmres->Dsvd;
 69:   PetscBLASInt   zero = 0,bn,bN,idummy,lwork;

 72:   PetscBLASIntCast(n,&bn);
 73:   PetscBLASIntCast(N,&bN);
 74:   idummy = -1;                  /* unused */
 75:   PetscBLASIntCast(5*N,&lwork);
 76:   if (nmax < n) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_SIZ,"Not enough room in work space r and c for eigenvalues");
 77:   *neig = n;

 79:   if (!n) return(0);

 81:   /* copy R matrix to work space */
 82:   PetscMemcpy(R,gmres->hes_origin,N*N*sizeof(PetscScalar));

 84:   /* compute eigenvalues */

 86:   /* for ESSL version need really cwork of length N (complex), 2N
 87:      (real); already at least 5N of space has been allocated */

 89:   PetscMalloc1(lwork,&work);
 90:   PetscFPTrapPush(PETSC_FP_TRAP_OFF);
 91:   PetscStackCallBLAS("LAPACKgeev",LAPACKgeev_(&zero,R,&bN,cwork,&sdummy,&idummy,&idummy,&bn,work,&lwork));
 92:   PetscFPTrapPop();
 93:   PetscFree(work);

 95:   /* For now we stick with the convention of storing the real and imaginary
 96:      components of evalues separately.  But is this what we really want? */
 97:   PetscMalloc1(n,&perm);

 99: #if !defined(PETSC_USE_COMPLEX)
100:   for (i=0; i<n; i++) {
101:     realpart[i] = cwork[2*i];
102:     perm[i]     = i;
103:   }
104:   PetscSortRealWithPermutation(n,realpart,perm);
105:   for (i=0; i<n; i++) {
106:     r[i] = cwork[2*perm[i]];
107:     c[i] = cwork[2*perm[i]+1];
108:   }
109: #else
110:   for (i=0; i<n; i++) {
111:     realpart[i] = PetscRealPart(cwork[i]);
112:     perm[i]     = i;
113:   }
114:   PetscSortRealWithPermutation(n,realpart,perm);
115:   for (i=0; i<n; i++) {
116:     r[i] = PetscRealPart(cwork[perm[i]]);
117:     c[i] = PetscImaginaryPart(cwork[perm[i]]);
118:   }
119: #endif
120:   PetscFree(perm);
121: #elif defined(PETSC_MISSING_LAPACK_GEEV)
123:   SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"GEEV - Lapack routine is unavailable\nNot able to provide eigen values.");
124: #elif !defined(PETSC_USE_COMPLEX)
125:   KSP_GMRES      *gmres = (KSP_GMRES*)ksp->data;
127:   PetscInt       n = gmres->it + 1,N = gmres->max_k + 1,i,*perm;
128:   PetscBLASInt   bn, bN, lwork, idummy, lierr;
129:   PetscScalar    *R        = gmres->Rsvd,*work = R + N*N;
130:   PetscScalar    *realpart = gmres->Dsvd,*imagpart = realpart + N,sdummy;

133:   PetscBLASIntCast(n,&bn);
134:   PetscBLASIntCast(N,&bN);
135:   PetscBLASIntCast(5*N,&lwork);
136:   PetscBLASIntCast(N,&idummy);
137:   if (nmax < n) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_SIZ,"Not enough room in work space r and c for eigenvalues");
138:   *neig = n;

140:   if (!n) return(0);

142:   /* copy R matrix to work space */
143:   PetscMemcpy(R,gmres->hes_origin,N*N*sizeof(PetscScalar));

145:   /* compute eigenvalues */
146:   PetscFPTrapPush(PETSC_FP_TRAP_OFF);
147:   PetscStackCallBLAS("LAPACKgeev",LAPACKgeev_("N","N",&bn,R,&bN,realpart,imagpart,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,&lierr));
148:   if (lierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in LAPACK routine %d",(int)lierr);
149:   PetscFPTrapPop();
150:   PetscMalloc1(n,&perm);
151:   for (i=0; i<n; i++) perm[i] = i;
152:   PetscSortRealWithPermutation(n,realpart,perm);
153:   for (i=0; i<n; i++) {
154:     r[i] = realpart[perm[i]];
155:     c[i] = imagpart[perm[i]];
156:   }
157:   PetscFree(perm);
158: #else
159:   KSP_GMRES      *gmres = (KSP_GMRES*)ksp->data;
161:   PetscInt       n  = gmres->it + 1,N = gmres->max_k + 1,i,*perm;
162:   PetscScalar    *R = gmres->Rsvd,*work = R + N*N,*eigs = work + 5*N,sdummy;
163:   PetscBLASInt   bn,bN,lwork,idummy,lierr;

166:   PetscBLASIntCast(n,&bn);
167:   PetscBLASIntCast(N,&bN);
168:   PetscBLASIntCast(5*N,&lwork);
169:   PetscBLASIntCast(N,&idummy);
170:   if (nmax < n) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_SIZ,"Not enough room in work space r and c for eigenvalues");
171:   *neig = n;

173:   if (!n) return(0);

175:   /* copy R matrix to work space */
176:   PetscMemcpy(R,gmres->hes_origin,N*N*sizeof(PetscScalar));

178:   /* compute eigenvalues */
179:   PetscFPTrapPush(PETSC_FP_TRAP_OFF);
180:   PetscStackCallBLAS("LAPACKgeev",LAPACKgeev_("N","N",&bn,R,&bN,eigs,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,gmres->Dsvd,&lierr));
181:   if (lierr) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in LAPACK routine");
182:   PetscFPTrapPop();
183:   PetscMalloc1(n,&perm);
184:   for (i=0; i<n; i++) perm[i] = i;
185:   for (i=0; i<n; i++) r[i] = PetscRealPart(eigs[i]);
186:   PetscSortRealWithPermutation(n,r,perm);
187:   for (i=0; i<n; i++) {
188:     r[i] = PetscRealPart(eigs[perm[i]]);
189:     c[i] = PetscImaginaryPart(eigs[perm[i]]);
190:   }
191:   PetscFree(perm);
192: #endif
193:   return(0);
194: }