pub unsafe extern "C" fn tsk_ld_calc_get_r2_array(
    self_: *mut tsk_ld_calc_t,
    a: tsk_id_t,
    direction: c_int,
    max_sites: tsk_size_t,
    max_distance: f64,
    r2: *mut f64,
    num_r2_values: *mut tsk_size_t
) -> c_int