.TH CSYMV 1 "November 2006" " LAPACK auxiliary routine (version 3.1) " " LAPACK auxiliary routine (version 3.1) " .SH NAME CSYMV - the matrix-vector operation y := alpha*A*x + beta*y, .SH SYNOPSIS .TP 18 SUBROUTINE CSYMV( UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY ) .TP 18 .ti +4 CHARACTER UPLO .TP 18 .ti +4 INTEGER INCX, INCY, LDA, N .TP 18 .ti +4 COMPLEX ALPHA, BETA .TP 18 .ti +4 COMPLEX A( LDA, * ), X( * ), Y( * ) .SH 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. .br .SH ARGUMENTS .TP 9 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 = \(aqU\(aq or \(aqu\(aq Only the upper triangular part of A is to be referenced. UPLO = \(aqL\(aq or \(aql\(aq Only the lower triangular part of A is to be referenced. Unchanged on exit. .TP 9 N (input) INTEGER On entry, N specifies the order of the matrix A. N must be at least zero. Unchanged on exit. .TP 9 ALPHA (input) COMPLEX On entry, ALPHA specifies the scalar alpha. Unchanged on exit. .TP 9 A (input) COMPLEX array, dimension ( LDA, N ) Before entry, with UPLO = \(aqU\(aq or \(aqu\(aq, 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 = \(aqL\(aq or \(aql\(aq, 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. .TP 9 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. .TP 9 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. .TP 9 INCX (input) INTEGER On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Unchanged on exit. .TP 9 BETA (input) 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. .TP 9 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. .TP 9 INCY (input) INTEGER On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Unchanged on exit.