sgebak()

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

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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

[in]	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. !>
[in]	SIDE	!> SIDE is CHARACTER*1 !> = 'R': V contains right eigenvectors; !> = 'L': V contains left eigenvectors. !>
[in]	N	!> N is INTEGER !> The number of rows of the matrix V. N >= 0. !>
[in]	ILO	!> ILO is INTEGER !>
[in]	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. !>
[in]	SCALE	!> SCALE is REAL array, dimension (N) !> Details of the permutation and scaling factors, as returned !> by SGEBAL. !>
[in]	M	!> M is INTEGER !> The number of columns of the matrix V. M >= 0. !>
[in,out]	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. !>
[in]	LDV	!> LDV is INTEGER !> The leading dimension of the array V. LDV >= max(1,N). !>
[out]	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.