Function sp_dgemv 

pub unsafe extern "C" fn sp_dgemv(
    trans: *mut c_char,
    alpha: c_double,
    A: *mut SuperMatrix,
    x: *mut c_double,
    incx: c_int,
    beta: c_double,
    y: *mut c_double,
    incy: c_int,
) -> c_int