
dlaqsy.f(3) LAPACK dlaqsy.f(3)
NAME
dlaqsy.f 
SYNOPSIS
Functions/Subroutines
subroutine dlaqsy (UPLO, N, A, LDA, S, SCOND, AMAX, EQUED)
DLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ.
Function/Subroutine Documentation
subroutine dlaqsy (characterUPLO, integerN, double precision, dimension( lda, * )A,
integerLDA, double precision, dimension( * )S, double precisionSCOND, double
precisionAMAX, characterEQUED)
DLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ.
Purpose:
DLAQSY equilibrates a symmetric matrix A using the scaling factors
in the vector S.
Parameters:
UPLO
UPLO is CHARACTER*1
Specifies whether the upper or lower triangular part of the
symmetric matrix A is stored.
= 'U': Upper triangular
= 'L': Lower triangular
N
N is INTEGER
The order of the matrix A. N >= 0.
A
A is DOUBLE PRECISION array, dimension (LDA,N)
On entry, the symmetric 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
LDA is INTEGER
The leading dimension of the array A. LDA >= max(N,1).
S
S is DOUBLE PRECISION array, dimension (N)
The scale factors for A.
SCOND
SCOND is DOUBLE PRECISION
Ratio of the smallest S(i) to the largest S(i).
AMAX
AMAX is DOUBLE PRECISION
Absolute value of largest matrix entry.
EQUED
EQUED is 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= 'Y': Equilibration was done, i.e., A has been replaced by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).
Internal 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.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
September 2012
Definition at line 134 of file dlaqsy.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 dlaqsy.f(3) 
