cher2(3) [debian man page]

CHER2(3)							   BLAS routine 							  CHER2(3)

NAME

       CHER2 - perform the hermitian rank 2 operation	A := alpha*x*conjg( y' ) + conjg( alpha )*y*conjg( x' ) + A,

SYNOPSIS

       SUBROUTINE CHER2 ( UPLO, N, ALPHA, X, INCX, Y, INCY, A, LDA )

	   COMPLEX	ALPHA

	   INTEGER	INCX, INCY, LDA, N

	   CHARACTER*1	UPLO

	   COMPLEX	A( LDA, * ), X( * ), Y( * )

PURPOSE

       CHER2  performs the hermitian rank 2 operation

       where alpha is a scalar, x and y are n element vectors 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  - COMPLEX 	.
	      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.

       Y      - COMPLEX 	 array of dimension at least
	      ( 1 + ( n - 1 )*abs( INCY ) ).  Before entry, the incremented array Y must contain the n element vector y.  Unchanged on exit.

       INCY   - INTEGER.
	      On entry, INCY specifies the increment for the elements of Y. INCY 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  triangu-
	      lar  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    - 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.

	      Level 2 Blas routine.

	      -- Written on 22-October-1986.  Jack Dongarra, Argonne National Lab.  Jeremy Du Croz, Nag Central Office.  Sven Hammarling, Nag Cen-
	      tral Office.  Richard Hanson, Sandia National Labs.

BLAS routine							  16 October 1992							  CHER2(3)