sgebak.f (3) - Linux Manuals
NAME
sgebak.f -
SYNOPSIS
Functions/Subroutines
subroutine sgebak (JOB, SIDE, N, ILO, IHI, SCALE, M, V, LDV, INFO)
SGEBAK
Function/Subroutine Documentation
subroutine sgebak (characterJOB, characterSIDE, integerN, integerILO, integerIHI, real, dimension( * )SCALE, integerM, real, dimension( ldv, * )V, integerLDV, integerINFO)
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.
SIDESIDE is CHARACTER*1 = 'R': V contains right eigenvectors; = 'L': V contains left eigenvectors.
NN is INTEGER The number of rows of the matrix V. N >= 0.
ILOILO is INTEGER
IHIIHI 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.
SCALESCALE is REAL array, dimension (N) Details of the permutation and scaling factors, as returned by SGEBAL.
MM is INTEGER The number of columns of the matrix V. M >= 0.
VV 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.
LDVLDV is INTEGER The leading dimension of the array V. LDV >= max(1,N).
INFOINFO 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.
Date:
- November 2011
Definition at line 130 of file sgebak.f.
Author
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