The FORTRAN level-2 BLAS call for this operation is
Here is replaced by S, D, C, or Z to indicate the datatype of the data (single, double, complex, double precision complex). Parameter UPLO indicates whether A is stored in the upper (UPLO = "Upper") or lower (UPLO = "Lower") triangular portion of array A. Parameter N holds the matrix dimension n . Parameters ALPHA and BETA hold the scaling factors and . Parameters A, X, and Y equal the addresses of where matrix A and vectors x and y start in memory. The leading dimension of the matrix is given in LDA and the strides for the vectors in INCX and INCY.
SUBROUTINE SYMV ( UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY )