Function gsl_sys::gsl_blas_dgemv

pub unsafe extern "C" fn gsl_blas_dgemv(
    TransA: CBLAS_TRANSPOSE_t, 
    alpha: f64, 
    A: *const gsl_matrix, 
    X: *const gsl_vector, 
    beta: f64, 
    Y: *mut gsl_vector
) -> c_int