
ZSPMV(l) ) ZSPMV(l)
NAME
ZSPMV  perform the matrixvector operation y := alpha*A*x + beta*y,
SYNOPSIS
SUBROUTINE ZSPMV( UPLO, N, ALPHA, AP, X, INCX, BETA, Y, INCY )
CHARACTER UPLO
INTEGER INCX, INCY, N
COMPLEX*16 ALPHA, BETA
COMPLEX*16 AP( * ), X( * ), Y( * )
PURPOSE
ZSPMV 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, supplied
in packed form.
ARGUMENTS
UPLO  CHARACTER*1
On entry, UPLO specifies whether the upper or lower triangular part of the matrix A
is supplied in the packed array AP as follows:
UPLO = 'U' or 'u' The upper triangular part of A is supplied in AP.
UPLO = 'L' or 'l' The lower triangular part of A is supplied in AP.
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*16
On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
AP  COMPLEX*16 array, dimension at least
( ( N*( N + 1 ) )/2 ). Before entry, with UPLO = 'U' or 'u', the array AP must
contain the upper triangular part of the symmetric matrix packed sequentially, col
umn by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a(
1, 2 ) and a( 2, 2 ) respectively, and so on. Before entry, with UPLO = 'L' or
'l', the array AP must contain the lower triangular part of the symmetric matrix
packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 )
and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on. Unchanged on
exit.
X  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  INTEGER
On entry, INCX specifies the increment for the elements of X. INCX must not be
zero. Unchanged on exit.
BETA  COMPLEX*16
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*16 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 ZSPMV(l) 
