zlaqhp.f man page

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= 'Y':  Equilibration was done, i.e., A has been replaced by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

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 127 of file zlaqhp.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

zlaqhp(3) is an alias of zlaqhp.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK