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zlaqsy.f -

# SYNOPSIS

## Functions/Subroutines

subroutine zlaqsy (UPLO, N, A, LDA, S, SCOND, AMAX, EQUED)

ZLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ.

# Function/Subroutine Documentation

## subroutine zlaqsy (characterUPLO, integerN, complex*16, dimension( lda, * )A, integerLDA, double precision, dimension( * )S, double precisionSCOND, double precisionAMAX, characterEQUED)

ZLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ.
Purpose:
``` ZLAQSY 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 COMPLEX*16 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= 'Y':  Equilibration was done, i.e., A has been replaced by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
NAG Ltd.
Date:
September 2012
Definition at line 135 of file zlaqsy.f.

# Author

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