Provided by: liblapack-doc_3.12.0-3build1.1_all 
NAME
gebak - gebak: back-transform eigvec
SYNOPSIS
Functions
subroutine cgebak (job, side, n, ilo, ihi, scale, m, v, ldv, info)
CGEBAK
subroutine dgebak (job, side, n, ilo, ihi, scale, m, v, ldv, info)
DGEBAK
subroutine sgebak (job, side, n, ilo, ihi, scale, m, v, ldv, info)
SGEBAK
subroutine zgebak (job, side, n, ilo, ihi, scale, m, v, ldv, info)
ZGEBAK
Detailed Description
Function Documentation
subroutine cgebak (character job, character side, integer n, integer ilo, integer ihi, real,
dimension( * ) scale, integer m, complex, dimension( ldv, * ) v, integer ldv, integer
info)
CGEBAK
Purpose:
CGEBAK forms the right or left eigenvectors of a complex general
matrix by backward transformation on the computed eigenvectors of the
balanced matrix output by CGEBAL.
Parameters
JOB
JOB is CHARACTER*1
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 CGEBAL.
SIDE
SIDE is CHARACTER*1
= 'R': V contains right eigenvectors;
= 'L': V contains left eigenvectors.
N
N is INTEGER
The number of rows of the matrix V. N >= 0.
ILO
ILO is INTEGER
IHI
IHI is INTEGER
The integers ILO and IHI determined by CGEBAL.
1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.
SCALE
SCALE is REAL array, dimension (N)
Details of the permutation and scaling factors, as returned
by CGEBAL.
M
M is INTEGER
The number of columns of the matrix V. M >= 0.
V
V is COMPLEX array, dimension (LDV,M)
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
LDV is INTEGER
The leading dimension of the array V. LDV >= max(1,N).
INFO
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
subroutine dgebak (character job, character side, integer n, integer ilo, integer ihi, double
precision, dimension( * ) scale, integer m, double precision, dimension( ldv, * ) v,
integer ldv, integer info)
DGEBAK
Purpose:
DGEBAK forms the right or left eigenvectors of a real general matrix
by backward transformation on the computed eigenvectors of the
balanced matrix output by DGEBAL.
Parameters
JOB
JOB is CHARACTER*1
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 DGEBAL.
SIDE
SIDE is CHARACTER*1
= 'R': V contains right eigenvectors;
= 'L': V contains left eigenvectors.
N
N is INTEGER
The number of rows of the matrix V. N >= 0.
ILO
ILO is INTEGER
IHI
IHI is INTEGER
The integers ILO and IHI determined by DGEBAL.
1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.
SCALE
SCALE is DOUBLE PRECISION array, dimension (N)
Details of the permutation and scaling factors, as returned
by DGEBAL.
M
M is INTEGER
The number of columns of the matrix V. M >= 0.
V
V is DOUBLE PRECISION array, dimension (LDV,M)
On entry, the matrix of right or left eigenvectors to be
transformed, as returned by DHSEIN or DTREVC.
On exit, V is overwritten by the transformed eigenvectors.
LDV
LDV is INTEGER
The leading dimension of the array V. LDV >= max(1,N).
INFO
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
subroutine sgebak (character job, character side, integer n, integer ilo, integer ihi, real,
dimension( * ) scale, integer m, real, dimension( ldv, * ) v, integer ldv, integer info)
SGEBAK
Purpose:
SGEBAK forms the right or left eigenvectors of a real general matrix
by backward transformation on the computed eigenvectors of the
balanced matrix output by SGEBAL.
Parameters
JOB
JOB is CHARACTER*1
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 SGEBAL.
SIDE
SIDE is CHARACTER*1
= 'R': V contains right eigenvectors;
= 'L': V contains left eigenvectors.
N
N is INTEGER
The number of rows of the matrix V. N >= 0.
ILO
ILO is INTEGER
IHI
IHI is INTEGER
The integers ILO and IHI determined by SGEBAL.
1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.
SCALE
SCALE is REAL array, dimension (N)
Details of the permutation and scaling factors, as returned
by SGEBAL.
M
M is INTEGER
The number of columns of the matrix V. M >= 0.
V
V is REAL array, dimension (LDV,M)
On entry, the matrix of right or left eigenvectors to be
transformed, as returned by SHSEIN or STREVC.
On exit, V is overwritten by the transformed eigenvectors.
LDV
LDV is INTEGER
The leading dimension of the array V. LDV >= max(1,N).
INFO
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
subroutine zgebak (character job, character side, integer n, integer ilo, integer ihi, double
precision, dimension( * ) scale, integer m, complex*16, dimension( ldv, * ) v, integer
ldv, integer info)
ZGEBAK
Purpose:
ZGEBAK 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.
Parameters
JOB
JOB is CHARACTER*1
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 ZGEBAL.
SIDE
SIDE is CHARACTER*1
= 'R': V contains right eigenvectors;
= 'L': V contains left eigenvectors.
N
N is INTEGER
The number of rows of the matrix V. N >= 0.
ILO
ILO is INTEGER
IHI
IHI is INTEGER
The integers ILO and IHI determined by ZGEBAL.
1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.
SCALE
SCALE is DOUBLE PRECISION array, dimension (N)
Details of the permutation and scaling factors, as returned
by ZGEBAL.
M
M is INTEGER
The number of columns of the matrix V. M >= 0.
V
V is COMPLEX*16 array, dimension (LDV,M)
On entry, the matrix of right or left eigenvectors to be
transformed, as returned by ZHSEIN or ZTREVC.
On exit, V is overwritten by the transformed eigenvectors.
LDV
LDV is INTEGER
The leading dimension of the array V. LDV >= max(1,N).
INFO
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Author
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