NAME
cher - perform the hermitian rank 1 operation A :=
alpha*x*conjg( x' ) + A
SYNOPSIS
SUBROUTINE CHER ( UPLO, N, ALPHA, X, INCX, A, LDA )
REAL ALPHA
INTEGER INCX, LDA, N
CHARACTER*1 UPLO
COMPLEX A( LDA, * ), X( * )
#include <sunperf.h>
void cher(char uplo, int n, float alpha, complex *cx, int
incx, complex *ca, int lda) ;
PURPOSE
CHER performs the hermitian rank 1 operation A :=
alpha*x*conjg( x' ) + A where alpha is a real scalar, x is
an n element vector and A is an n by n hermitian matrix.
PARAMETERS
UPLO - CHARACTER*1.
On entry, UPLO specifies whether the upper or
lower triangular part of the array A is to be
referenced as follows:
UPLO = 'U' or 'u' Only the upper triangular part
of A is to be referenced.
UPLO = 'L' or 'l' Only the lower triangular part
of A is to be referenced.
Unchanged on exit.
N - INTEGER.
On entry, N specifies the order of the matrix A.
N must be at least zero. Unchanged on exit.
ALPHA - REAL .
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
X - COMPLEX array of dimension at least
( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the
incremented array X must contain the n element
vector x. Unchanged on exit.
INCX - INTEGER.
On entry, INCX specifies the increment for the
elements of X. INCX must not be zero. Unchanged
on exit.
A - COMPLEX array of DIMENSION ( LDA, n ).
Before entry with UPLO = 'U' or 'u', the leading
n by n upper triangular part of the array A must
contain the upper triangular part of the hermitian
matrix and the strictly lower triangular part of A
is not referenced. On exit, the upper triangular
part of the array A is overwritten by the upper
triangular part of the updated matrix. Before
entry with UPLO = 'L' or 'l', the leading n by n
lower triangular part of the array A must contain
the lower triangular part of the hermitian matrix
and the strictly upper triangular part of A is not
referenced. On exit, the lower triangular part of
the array A is overwritten by the lower triangular
part of the updated matrix. Note that the ima-
ginary parts of the diagonal elements need not be
set, they are assumed to be zero, and on exit they
are set to zero.
LDA - INTEGER.
On entry, LDA specifies the first dimension of A
as declared in the calling (sub) program. LDA must
be at least max( 1, n ). Unchanged on exit.
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