zgebak(3P) Sun Performance Library zgebak(3P)NAMEzgebak - form the right or left eigenvectors of a complex general
matrix by backward transformation on the computed eigenvectors of the
balanced matrix output by ZGEBAL
SYNOPSIS
SUBROUTINE ZGEBAK(JOB, SIDE, N, ILO, IHI, SCALE, M, V, LDV, INFO)
CHARACTER * 1 JOB, SIDE
DOUBLE COMPLEX V(LDV,*)
INTEGER N, ILO, IHI, M, LDV, INFO
DOUBLE PRECISION SCALE(*)
SUBROUTINE ZGEBAK_64(JOB, SIDE, N, ILO, IHI, SCALE, M, V, LDV, INFO)
CHARACTER * 1 JOB, SIDE
DOUBLE COMPLEX V(LDV,*)
INTEGER*8 N, ILO, IHI, M, LDV, INFO
DOUBLE PRECISION SCALE(*)
F95 INTERFACE
SUBROUTINE GEBAK(JOB, SIDE, [N], ILO, IHI, SCALE, [M], V, [LDV],
[INFO])
CHARACTER(LEN=1) :: JOB, SIDE
COMPLEX(8), DIMENSION(:,:) :: V
INTEGER :: N, ILO, IHI, M, LDV, INFO
REAL(8), DIMENSION(:) :: SCALE
SUBROUTINE GEBAK_64(JOB, SIDE, [N], ILO, IHI, SCALE, [M], V, [LDV],
[INFO])
CHARACTER(LEN=1) :: JOB, SIDE
COMPLEX(8), DIMENSION(:,:) :: V
INTEGER(8) :: N, ILO, IHI, M, LDV, INFO
REAL(8), DIMENSION(:) :: SCALE
C INTERFACE
#include <sunperf.h>
void zgebak(char job, char side, int n, int ilo, int ihi, double
*scale, int m, doublecomplex *v, int ldv, int *info);
void zgebak_64(char job, char side, long n, long ilo, long ihi, double
*scale, long m, doublecomplex *v, long ldv, long *info);
PURPOSEzgebak forms the right or left eigenvectors of a complex general matrix
by backward transformation on the computed eigenvectors of the balanced
matrix output by ZGEBAL.
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 transfor‐
mations for both permutation and scaling. JOB must be the
same as the argument JOB supplied to ZGEBAL.
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 integer ILO determined by ZGEBAL. 1 <= ILO <= IHI <= N,
if N > 0; ILO=1 and IHI=0, if N=0.
IHI (input)
The integer IHI determined by ZGEBAL. 1 <= ILO <= IHI <= N,
if N > 0; ILO=1 and IHI=0, if N=0.
SCALE (input)
Details of the permutation and scaling factors, as returned
by ZGEBAL.
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 CHSEIN or CTREVC. On exit, V is
overwritten by the transformed eigenvectors.
LDV (input)
The leading dimension of the array V. LDV >= max(1,N).
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value.
6 Mar 2009 zgebak(3P)