cher

NAME

cher - perform the hermitian rank 1 operation A := alpha*x*conjg( x' ) + A

SYNOPSIS 

  SUBROUTINE CHER( UPLO, N, ALPHA, X, INCX, A, LDA)
  CHARACTER * 1 UPLO
  COMPLEX X(*), A(LDA,*)
  INTEGER N, INCX, LDA
  REAL ALPHA
 
  SUBROUTINE CHER_64( UPLO, N, ALPHA, X, INCX, A, LDA)
  CHARACTER * 1 UPLO
  COMPLEX X(*), A(LDA,*)
  INTEGER*8 N, INCX, LDA
  REAL ALPHA

F95 INTERFACE 

  SUBROUTINE HER( UPLO, [N], ALPHA, X, [INCX], A, [LDA])
  CHARACTER(LEN=1) :: UPLO
  COMPLEX, DIMENSION(:) :: X
  COMPLEX, DIMENSION(:,:) :: A
  INTEGER :: N, INCX, LDA
  REAL :: ALPHA
 
  SUBROUTINE HER_64( UPLO, [N], ALPHA, X, [INCX], A, [LDA])
  CHARACTER(LEN=1) :: UPLO
  COMPLEX, DIMENSION(:) :: X
  COMPLEX, DIMENSION(:,:) :: A
  INTEGER(8) :: N, INCX, LDA
  REAL :: ALPHA

C INTERFACE

#include <sunperf.h>

void cher(char uplo, int n, float alpha, complex *x, int incx, complex *a, int lda);

void cher_64(char uplo, long n, float alpha, complex *x, long incx, complex *a, long 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.

ARGUMENTS

* UPLO (input)
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 (input)
On entry, N specifies the order of the matrix A. N >= 0. Unchanged on exit.

* ALPHA (input)
On entry, ALPHA specifies the scalar alpha. Unchanged on exit.

* X (input)
( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the n element vector x. Unchanged on exit.

* INCX (input)
On entry, INCX specifies the increment for the elements of X. INCX <> 0. Unchanged on exit.

* A (input/output)
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 imaginary parts of the diagonal elements need not be set, they are assumed to be zero, and on exit they are set to zero.

* LDA (input)
On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA >= max( 1, n ). Unchanged on exit.