zhpr()

subroutine zhpr	(	character	uplo,
		integer	n,
		double precision	alpha,
		complex*16, dimension(*)	x,
		integer	incx,
		complex*16, dimension(*)	ap )

ZHPR

Purpose:

!>
!> ZHPR    performs the hermitian rank 1 operation
!>
!>    A := alpha*x*x**H + A,
!>
!> where alpha is a real scalar, x is an n element vector and A is an
!> n by n hermitian matrix, supplied in packed form.
!> 

Parameters

[in]	UPLO	!> UPLO is CHARACTER*1 !> On entry, UPLO specifies whether the upper or lower !> triangular part of the matrix A is supplied in the packed !> array AP as follows: !> !> UPLO = 'U' or 'u' The upper triangular part of A is !> supplied in AP. !> !> UPLO = 'L' or 'l' The lower triangular part of A is !> supplied in AP. !>
[in]	N	!> N is INTEGER !> On entry, N specifies the order of the matrix A. !> N must be at least zero. !>
[in]	ALPHA	!> ALPHA is DOUBLE PRECISION. !> On entry, ALPHA specifies the scalar alpha. !>
[in]	X	!> X is COMPLEX*16 array, dimension at least !> ( 1 + ( n - 1 )*abs( INCX ) ). !> Before entry, the incremented array X must contain the n !> element vector x. !>
[in]	INCX	!> INCX is INTEGER !> On entry, INCX specifies the increment for the elements of !> X. INCX must not be zero. !>
[in,out]	AP	!> AP is COMPLEX*16 array, dimension at least !> ( ( n*( n + 1 ) )/2 ). !> Before entry with UPLO = 'U' or 'u', the array AP must !> contain the upper triangular part of the hermitian matrix !> packed sequentially, column by column, so that AP( 1 ) !> contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) !> and a( 2, 2 ) respectively, and so on. On exit, the array !> AP is overwritten by the upper triangular part of the !> updated matrix. !> Before entry with UPLO = 'L' or 'l', the array AP must !> contain the lower triangular part of the hermitian matrix !> packed sequentially, column by column, so that AP( 1 ) !> contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) !> and a( 3, 1 ) respectively, and so on. On exit, the array !> AP is overwritten by the lower triangular part of the !> updated matrix. !> Note that the imaginary parts of the diagonal elements need !> not be set, they are assumed to be zero, and on exit they !> are set to zero. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:

!>
!>  Level 2 Blas routine.
!>
!>  -- Written on 22-October-1986.
!>     Jack Dongarra, Argonne National Lab.
!>     Jeremy Du Croz, Nag Central Office.
!>     Sven Hammarling, Nag Central Office.
!>     Richard Hanson, Sandia National Labs.
!>