
CSYMV(l) ) CSYMV(l)
NAME
CSYMV  perform the matrixvector operation y := alpha*A*x + beta*y,
SYNOPSIS
SUBROUTINE CSYMV( UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY )
CHARACTER UPLO
INTEGER INCX, INCY, LDA, N
COMPLEX ALPHA, BETA
COMPLEX A( LDA, * ), X( * ), Y( * )
PURPOSE
CSYMV performs the matrixvector operation y := alpha*A*x + beta*y, where alpha and beta
are scalars, x and y are n element vectors and A is an n by n symmetric matrix.
ARGUMENTS
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.
A  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 symmetric matrix and the
strictly lower triangular part of A is not referenced. 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. Unchanged on exit.
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.
X  COMPLEX 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  INTEGER
On entry, INCX specifies the increment for the elements of X. INCX must not be
zero. Unchanged on exit.
BETA  COMPLEX
On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need
not be set on input. Unchanged on exit.
Y  COMPLEX array, dimension at least
( 1 + ( N  1 )*abs( INCY ) ). Before entry, the incremented array Y must contain
the n element vector y. On exit, Y is overwritten by the updated vector y.
INCY  INTEGER
On entry, INCY specifies the increment for the elements of Y. INCY must not be
zero. Unchanged on exit.
LAPACK version 3.0 15 June 2000 CSYMV(l) 
