CLAQHE(l) ) CLAQHE(l)NAME
CLAQHE - equilibrate a Hermitian matrix A using the scaling factors in
the vector S
SYNOPSIS
SUBROUTINE CLAQHE( UPLO, N, A, LDA, S, SCOND, AMAX, EQUED )
CHARACTER EQUED, UPLO
INTEGER LDA, N
REAL AMAX, SCOND
REAL S( * )
COMPLEX A( LDA, * )
PURPOSE
CLAQHE equilibrates a Hermitian matrix A using the scaling factors in
the vector S.
ARGUMENTS
UPLO (input) CHARACTER*1
Specifies whether the upper or lower triangular part of the
Hermitian matrix A is stored. = 'U': Upper triangular
= 'L': Lower triangular
N (input) INTEGER
The order of the matrix A. N >= 0.
A (input/output) COMPLEX array, dimension (LDA,N)
On entry, the Hermitian matrix A. If UPLO = 'U', the leading n
by n upper triangular part of A contains the upper triangular
part of the matrix A, and the strictly lower triangular part of
A is not referenced. If UPLO = 'L', the leading n by n lower
triangular part of A contains the lower triangular part of the
matrix A, and the strictly upper triangular part of A is not
referenced.
On exit, if EQUED = 'Y', the equilibrated matrix: diag(S) * A *
diag(S).
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(N,1).
S (input) REAL array, dimension (N)
The scale factors for A.
SCOND (input) REAL
Ratio of the smallest S(i) to the largest S(i).
AMAX (input) REAL
Absolute value of largest matrix entry.
EQUED (output) CHARACTER*1
Specifies whether or not equilibration was done. = 'N': No
equilibration.
= 'Y': Equilibration was done, i.e., A has been replaced by
diag(S) * A * diag(S).
PARAMETERS
THRESH is a threshold value used to decide if scaling should be done
based on the ratio of the scaling factors. If SCOND < THRESH, scaling
is done.
LARGE and SMALL are threshold values used to decide if scaling should
be done based on the absolute size of the largest matrix element. If
AMAX > LARGE or AMAX < SMALL, scaling is done.
LAPACK version 3.0 15 June 2000 CLAQHE(l)
