xref: /petsc/src/ksp/ksp/impls/gmres/gmreig.c (revision a790c00499656cdc34e95ec8f15f35cf5f4cdcbb)
1 
2 #include <../src/ksp/ksp/impls/gmres/gmresimpl.h>
3 #include <petscblaslapack.h>
4 
5 #undef __FUNCT__
6 #define __FUNCT__ "KSPComputeExtremeSingularValues_GMRES"
7 PetscErrorCode KSPComputeExtremeSingularValues_GMRES(KSP ksp,PetscReal *emax,PetscReal *emin)
8 {
9 #if defined(PETSC_MISSING_LAPACK_GESVD)
10   PetscFunctionBegin;
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(((PetscObject)ksp)->comm,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;
18   PetscErrorCode ierr;
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;
23 
24   PetscFunctionBegin;
25   bn = PetscBLASIntCast(n);
26   bN = PetscBLASIntCast(N);
27   lwork = PetscBLASIntCast(5*N);
28   idummy = PetscBLASIntCast(N);
29   if (n <= 0) {
30     *emax = *emin = 1.0;
31     PetscFunctionReturn(0);
32   }
33   /* copy R matrix to work space */
34   ierr = PetscMemcpy(R,gmres->hh_origin,(gmres->max_k+2)*(gmres->max_k+1)*sizeof(PetscScalar));CHKERRQ(ierr);
35 
36   /* zero below diagonal garbage */
37   for (i=0; i<n; i++) {
38     R[i*N+i+1] = 0.0;
39   }
40 
41   /* compute Singular Values */
42   ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
43 #if !defined(PETSC_USE_COMPLEX)
44   LAPACKgesvd_("N","N",&bn,&bn,R,&bN,realpart,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,&lierr);
45 #else
46   LAPACKgesvd_("N","N",&bn,&bn,R,&bN,realpart,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,realpart+N,&lierr);
47 #endif
48   if (lierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in SVD Lapack routine %d",(int)lierr);
49   ierr = PetscFPTrapPop();CHKERRQ(ierr);
50 
51   *emin = realpart[n-1];
52   *emax = realpart[0];
53 #endif
54   PetscFunctionReturn(0);
55 }
56 
57 /* ------------------------------------------------------------------------ */
58 /* ESSL has a different calling sequence for dgeev() and zgeev() than standard LAPACK */
59 #undef __FUNCT__
60 #define __FUNCT__ "KSPComputeEigenvalues_GMRES"
61 PetscErrorCode KSPComputeEigenvalues_GMRES(KSP ksp,PetscInt nmax,PetscReal *r,PetscReal *c,PetscInt *neig)
62 {
63 #if defined(PETSC_HAVE_ESSL)
64   KSP_GMRES      *gmres = (KSP_GMRES*)ksp->data;
65   PetscErrorCode ierr;
66   PetscInt       n = gmres->it + 1,N = gmres->max_k + 1,lwork = 5*N;
67   PetscInt       i,*perm;
68   PetscScalar    *R = gmres->Rsvd;
69   PetscScalar    *cwork = R + N*N,sdummy;
70   PetscReal      *work,*realpart = gmres->Dsvd ;
71   PetscBLASInt   zero = 0,idummy = PetscBLASIntCast(N);
72 
73   PetscFunctionBegin;
74   if (nmax < n) SETERRQ(((PetscObject)ksp)->comm,PETSC_ERR_ARG_SIZ,"Not enough room in work space r and c for eigenvalues");
75   *neig = n;
76 
77   if (!n) {
78     PetscFunctionReturn(0);
79   }
80   /* copy R matrix to work space */
81   ierr = PetscMemcpy(R,gmres->hes_origin,N*N*sizeof(PetscScalar));CHKERRQ(ierr);
82 
83   /* compute eigenvalues */
84 
85   /* for ESSL version need really cwork of length N (complex), 2N
86      (real); already at least 5N of space has been allocated */
87 
88   ierr = PetscMalloc(lwork*sizeof(PetscReal),&work);CHKERRQ(ierr);
89   ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
90   LAPACKgeev_(&zero,R,&idummy,cwork,&sdummy,&idummy,&idummy,&n,work,&lwork);
91   ierr = PetscFPTrapPop();CHKERRQ(ierr);
92   ierr = PetscFree(work);CHKERRQ(ierr);
93 
94   /* For now we stick with the convention of storing the real and imaginary
95      components of evalues separately.  But is this what we really want? */
96   ierr = PetscMalloc(n*sizeof(PetscInt),&perm);CHKERRQ(ierr);
97 
98 #if !defined(PETSC_USE_COMPLEX)
99   for (i=0; i<n; i++) {
100     realpart[i] = cwork[2*i];
101     perm[i]     = i;
102   }
103   ierr = PetscSortRealWithPermutation(n,realpart,perm);CHKERRQ(ierr);
104   for (i=0; i<n; i++) {
105     r[i] = cwork[2*perm[i]];
106     c[i] = cwork[2*perm[i]+1];
107   }
108 #else
109   for (i=0; i<n; i++) {
110     realpart[i] = PetscRealPart(cwork[i]);
111     perm[i]     = i;
112   }
113   ierr = PetscSortRealWithPermutation(n,realpart,perm);CHKERRQ(ierr);
114   for (i=0; i<n; i++) {
115     r[i] = PetscRealPart(cwork[perm[i]]);
116     c[i] = PetscImaginaryPart(cwork[perm[i]]);
117   }
118 #endif
119   ierr = PetscFree(perm);CHKERRQ(ierr);
120 #elif defined(PETSC_MISSING_LAPACK_GEEV)
121   PetscFunctionBegin;
122   SETERRQ(((PetscObject)ksp)->comm,PETSC_ERR_SUP,"GEEV - Lapack routine is unavailable\nNot able to provide eigen values.");
123 #elif !defined(PETSC_USE_COMPLEX)
124   KSP_GMRES      *gmres = (KSP_GMRES*)ksp->data;
125   PetscErrorCode ierr;
126   PetscInt       n = gmres->it + 1,N = gmres->max_k + 1,i,*perm;
127   PetscBLASInt   bn, bN, lwork, idummy, lierr;
128   PetscScalar    *R = gmres->Rsvd,*work = R + N*N;
129   PetscScalar    *realpart = gmres->Dsvd,*imagpart = realpart + N,sdummy;
130 
131   PetscFunctionBegin;
132   bn = PetscBLASIntCast(n);
133   bN = PetscBLASIntCast(N);
134   lwork = PetscBLASIntCast(5*N);
135   idummy = PetscBLASIntCast(N);
136   if (nmax < n) SETERRQ(((PetscObject)ksp)->comm,PETSC_ERR_ARG_SIZ,"Not enough room in work space r and c for eigenvalues");
137   *neig = n;
138 
139   if (!n) {
140     PetscFunctionReturn(0);
141   }
142 
143   /* copy R matrix to work space */
144   ierr = PetscMemcpy(R,gmres->hes_origin,N*N*sizeof(PetscScalar));CHKERRQ(ierr);
145 
146   /* compute eigenvalues */
147   ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
148   LAPACKgeev_("N","N",&bn,R,&bN,realpart,imagpart,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,&lierr);
149   if (lierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in LAPACK routine %d",(int)lierr);
150   ierr = PetscFPTrapPop();CHKERRQ(ierr);
151   ierr = PetscMalloc(n*sizeof(PetscInt),&perm);CHKERRQ(ierr);
152   for (i=0; i<n; i++) { perm[i] = i;}
153   ierr = PetscSortRealWithPermutation(n,realpart,perm);CHKERRQ(ierr);
154   for (i=0; i<n; i++) {
155     r[i] = realpart[perm[i]];
156     c[i] = imagpart[perm[i]];
157   }
158   ierr = PetscFree(perm);CHKERRQ(ierr);
159 #else
160   KSP_GMRES      *gmres = (KSP_GMRES*)ksp->data;
161   PetscErrorCode ierr;
162   PetscInt       n = gmres->it + 1,N = gmres->max_k + 1,i,*perm;
163   PetscScalar    *R = gmres->Rsvd,*work = R + N*N,*eigs = work + 5*N,sdummy;
164   PetscBLASInt   bn,bN,lwork,idummy,lierr;
165 
166   PetscFunctionBegin;
167   bn = PetscBLASIntCast(n);
168   bN = PetscBLASIntCast(N);
169   lwork = PetscBLASIntCast(5*N);
170   idummy = PetscBLASIntCast(N);
171   if (nmax < n) SETERRQ(((PetscObject)ksp)->comm,PETSC_ERR_ARG_SIZ,"Not enough room in work space r and c for eigenvalues");
172   *neig = n;
173 
174   if (!n) {
175     PetscFunctionReturn(0);
176   }
177   /* copy R matrix to work space */
178   ierr = PetscMemcpy(R,gmres->hes_origin,N*N*sizeof(PetscScalar));CHKERRQ(ierr);
179 
180   /* compute eigenvalues */
181   ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
182   LAPACKgeev_("N","N",&bn,R,&bN,eigs,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,gmres->Dsvd,&lierr);
183   if (lierr) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in LAPACK routine");
184   ierr = PetscFPTrapPop();CHKERRQ(ierr);
185   ierr = PetscMalloc(n*sizeof(PetscInt),&perm);CHKERRQ(ierr);
186   for (i=0; i<n; i++) { perm[i] = i;}
187   for (i=0; i<n; i++) { r[i]    = PetscRealPart(eigs[i]);}
188   ierr = PetscSortRealWithPermutation(n,r,perm);CHKERRQ(ierr);
189   for (i=0; i<n; i++) {
190     r[i] = PetscRealPart(eigs[perm[i]]);
191     c[i] = PetscImaginaryPart(eigs[perm[i]]);
192   }
193   ierr = PetscFree(perm);CHKERRQ(ierr);
194 #endif
195   PetscFunctionReturn(0);
196 }
197 
198 
199 
200 
201