ssymv (l)  Linux Manuals
ssymv: performs the matrixvector operation y := alpha*A*x + beta*y,
NAME
SSYMV  performs the matrixvector operation y := alpha*A*x + beta*y,SYNOPSIS
 SUBROUTINE SSYMV(UPLO,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
 REAL ALPHA,BETA
 INTEGER INCX,INCY,LDA,N
 CHARACTER UPLO
 REAL A(LDA,*),X(*),Y(*)
PURPOSE
SSYMV performs the matrixvector 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  CHARACTER*1.

On entry, UPLO specifies whether the upper or lower
triangular part of the array A is to be referenced as
follows:
UPLO = aqUaq or aquaq Only the upper triangular part of A is to be referenced.
UPLO = aqLaq or aqlaq 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  REAL .
 On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
 A  REAL array of DIMENSION ( LDA, n ).
 Before entry with UPLO = aqUaq or aquaq, 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 = aqLaq or aqlaq, 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  REAL array of 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  REAL .
 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  REAL array of 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.
FURTHER DETAILS
Level 2 Blas routine.
 Written on 22October1986.
Jack Dongarra, Argonne National Lab.
Jeremy Du Croz, Nag Central Office.
Sven Hammarling, Nag Central Office.
Richard Hanson, Sandia National Labs.