cspr()

subroutine cspr	(	character	uplo,
		integer	n,
		complex	alpha,
		complex, dimension( * )	x,
		integer	incx,
		complex, dimension( * )	ap )

CSPR performs the symmetrical rank-1 update of a complex symmetric packed matrix.

Download CSPR + dependencies [TGZ] [ZIP] [TXT]

Purpose:

!>
!> CSPR    performs the symmetric rank 1 operation
!>
!>    A := alpha*x*x**H + A,
!>
!> where alpha is a complex scalar, x is an n element vector and A is an
!> n by n symmetric 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. !> !> Unchanged on exit. !>
[in]	N	!> N is INTEGER !> On entry, N specifies the order of the matrix A. !> N must be at least zero. !> Unchanged on exit. !>
[in]	ALPHA	!> ALPHA is COMPLEX !> On entry, ALPHA specifies the scalar alpha. !> Unchanged on exit. !>
[in]	X	!> X is COMPLEX array, dimension at least !> ( 1 + ( N - 1 )*abs( INCX ) ). !> Before entry, the incremented array X must contain the N- !> element vector x. !> Unchanged on exit. !>
[in]	INCX	!> INCX is INTEGER !> On entry, INCX specifies the increment for the elements of !> X. INCX must not be zero. !> Unchanged on exit. !>
[in,out]	AP	!> AP is COMPLEX 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 symmetric 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 symmetric 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.