CSYMV(1) LAPACK auxiliary routine (version 3.2) CSYMV(1)NAME
CSYMV - performs the matrix-vector 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 matrix-vector operation where alpha and beta are
scalars, x and y are n element vectors 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 refer‐
enced. 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
On entry, ALPHA specifies the scalar alpha. Unchanged on
exit.
A (input) 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 sym‐
metric matrix and the strictly upper triangular part of A is
not referenced. Unchanged on exit.
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.
X (input) 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 (input) INTEGER
On entry, INCX specifies the increment for the elements of X.
INCX must not be zero. Unchanged on exit.
BETA (input) COMPLEX
On entry, BETA specifies the scalar beta. When BETA is sup‐
plied as zero then Y need not be set on input. Unchanged on
exit.
Y (input/output) 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 (input) INTEGER
On entry, INCY specifies the increment for the elements of Y.
INCY must not be zero. Unchanged on exit.
LAPACK auxiliary routine (versioNovember 2008 CSYMV(1)
