CHER2  performs the hermitian rank 2 operation


    A := alpha*x*y**H + conjg( alpha )*y*x**H + A,


 where alpha is a scalar, x and y are n element vectors and A is an n


 by n hermitian matrix.

UPLO

          UPLO is 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.

N

          N is INTEGER


           On entry, N specifies the order of the matrix A.


           N must be at least zero.

ALPHA

          ALPHA is COMPLEX


           On entry, ALPHA specifies the scalar alpha.

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.

INCX

          INCX is INTEGER


           On entry, INCX specifies the increment for the elements of


           X. INCX must not be zero.

Y

          Y is COMPLEX array, dimension at least


           ( 1 + ( n - 1 )*abs( INCY ) ).


           Before entry, the incremented array Y must contain the n


           element vector y.

INCY

          INCY is INTEGER


           On entry, INCY specifies the increment for the elements of


           Y. INCY must not be zero.

A

          A is COMPLEX array, 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 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

          LDA is 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 ).

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

December 2016

  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.