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zlaqhp.f -

# SYNOPSIS

## Functions/Subroutines

subroutine zlaqhp (UPLO, N, AP, S, SCOND, AMAX, EQUED)

ZLAQHP scales a Hermitian matrix stored in packed form.

# Function/Subroutine Documentation

## subroutine zlaqhp (characterUPLO, integerN, complex*16, dimension( * )AP, double precision, dimension( * )S, double precisionSCOND, double precisionAMAX, characterEQUED)

ZLAQHP scales a Hermitian matrix stored in packed form.
Purpose:
``` ZLAQHP equilibrates a Hermitian 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
Hermitian matrix A is stored.
= 'U':  Upper triangular
= 'L':  Lower triangular
```
N
```          N is INTEGER
The order of the matrix A.  N >= 0.
```
AP
```          AP is COMPLEX*16 array, dimension (N*(N+1)/2)
On entry, the upper or lower triangle of the Hermitian matrix
A, packed columnwise in a linear array.  The j-th column of A
is stored in the array AP as follows:
if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.

On exit, the equilibrated matrix:  diag(S) * A * diag(S), in
the same storage format as A.
```
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= 'Y':  Equilibration was done, i.e., A has been replaced by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 127 of file zlaqhp.f.

# Author

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