sggbak - genvalue problem A*x = lambda*B*x, by backward transformation on the computed eigenvectors of the balanced pair of matrices output by SGGBAL
SUBROUTINE SGGBAK(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER*1 JOB, SIDE INTEGER N, ILO, IHI, M, LDV, INFO REAL LSCALE(*), RSCALE(*), V(LDV,*) SUBROUTINE SGGBAK_64(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER*1 JOB, SIDE INTEGER*8 N, ILO, IHI, M, LDV, INFO REAL LSCALE(*), RSCALE(*), V(LDV,*) F95 INTERFACE SUBROUTINE GGBAK(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER(LEN=1) :: JOB, SIDE INTEGER :: N, ILO, IHI, M, LDV, INFO REAL, DIMENSION(:) :: LSCALE, RSCALE REAL, DIMENSION(:,:) :: V SUBROUTINE GGBAK_64(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER(LEN=1) :: JOB, SIDE INTEGER(8) :: N, ILO, IHI, M, LDV, INFO REAL, DIMENSION(:) :: LSCALE, RSCALE REAL, DIMENSION(:,:) :: V C INTERFACE #include <sunperf.h> void sggbak(char job, char side, int n, int ilo, int ihi, float *lscale, float *rscale, int m, float *v, int ldv, int *info); void sggbak_64(char job, char side, long n, long ilo, long ihi, float *lscale, float *rscale, long m, float *v, long ldv, long *info);
Oracle Solaris Studio Performance Library sggbak(3P) NAME sggbak - form the right or left eigenvectors of a real generalized ei- genvalue problem A*x = lambda*B*x, by backward transformation on the computed eigenvectors of the balanced pair of matrices output by SGGBAL SYNOPSIS SUBROUTINE SGGBAK(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER*1 JOB, SIDE INTEGER N, ILO, IHI, M, LDV, INFO REAL LSCALE(*), RSCALE(*), V(LDV,*) SUBROUTINE SGGBAK_64(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER*1 JOB, SIDE INTEGER*8 N, ILO, IHI, M, LDV, INFO REAL LSCALE(*), RSCALE(*), V(LDV,*) F95 INTERFACE SUBROUTINE GGBAK(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER(LEN=1) :: JOB, SIDE INTEGER :: N, ILO, IHI, M, LDV, INFO REAL, DIMENSION(:) :: LSCALE, RSCALE REAL, DIMENSION(:,:) :: V SUBROUTINE GGBAK_64(JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO) CHARACTER(LEN=1) :: JOB, SIDE INTEGER(8) :: N, ILO, IHI, M, LDV, INFO REAL, DIMENSION(:) :: LSCALE, RSCALE REAL, DIMENSION(:,:) :: V C INTERFACE #include <sunperf.h> void sggbak(char job, char side, int n, int ilo, int ihi, float *lscale, float *rscale, int m, float *v, int ldv, int *info); void sggbak_64(char job, char side, long n, long ilo, long ihi, float *lscale, float *rscale, long m, float *v, long ldv, long *info); PURPOSE sggbak forms the right or left eigenvectors of a real generalized ei- genvalue problem A*x = lambda*B*x, by backward transformation on the computed eigenvectors of the balanced pair of matrices output by SGG- BAL. ARGUMENTS JOB (input) Specifies the type of backward transformation required: = 'N': do nothing, return immediately; = 'P': do backward transformation for permutation only; = 'S': do backward transformation for scaling only; = 'B': do backward transformations for both permutation and scaling. JOB must be the same as the argument JOB supplied to SGGBAL. SIDE (input) = 'R': V contains right eigenvectors; = 'L': V contains left eigenvectors. N (input) The number of rows of the matrix V. N >= 0. ILO (input) The integers ILO and IHI determined by SGGBAL. 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0. IHI (input) See the description for ILO. LSCALE (input) Details of the permutations and/or scaling factors applied to the left side of A and B, as returned by SGGBAL. RSCALE (input) Details of the permutations and/or scaling factors applied to the right side of A and B, as returned by SGGBAL. M (input) The number of columns of the matrix V. M >= 0. V (input/output) On entry, the matrix of right or left eigenvectors to be transformed, as returned by STGEVC. On exit, V is overwrit- ten by the transformed eigenvectors. LDV (input) The leading dimension of the matrix V. LDV >= max(1,N). INFO (output) = 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value. FURTHER DETAILS See R.C. Ward, Balancing the generalized eigenvalue problem, SIAM J. Sci. Stat. Comp. 2 (1981), 141-152. 7 Nov 2015 sggbak(3P)