ZSYR(3f)

NAME
ZSYR - the symmetric rank 1 operation A := alpha*x*( x' ) + A,

SYNOPSIS

SUBROUTINE ZSYR(
    UPLO, N, ALPHA, X, INCX, A, LDA )

CHARACTER
    UPLO

INTEGER
    INCX, LDA, N

COMPLEX*16
    ALPHA

COMPLEX*16
    A( LDA, * ), X( * )

PURPOSE
ZSYR performs the symmetric rank 1 operation where alpha is a complex scalar, x is an n element vector and A is an n by n symmetric matrix.

ARGUMENTS

UPLO     (input) 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        (input) INTEGER
    On entry, N specifies the order of the matrix A. N must be at least zero. Unchanged on exit.

ALPHA    (input) COMPLEX*16
    On entry, ALPHA specifies the scalar alpha. Unchanged on exit.

X        (input) COMPLEX*16 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.

INCX     (input) INTEGER
    On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Unchanged on exit.

A        (input/output) COMPLEX*16 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 symmetric 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 symmetric 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.

LDA      (input) 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.