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 lower (UPLO = "Lower") or upper (UPLO = "Upper") triangular part of A. Parameter N holds the matrix dimension n . Parameter ALPHA holds the scaling factor . Parameters a and x equal the addresses of where matrix A and vector x start in memory. The leading dimensions of the matrix is given in LDA and the stride of the vector in INCX.
SUBROUTINE SYR ( UPLO, N, ALPHA, X, INCX, A, LDA )