我的问题是基于似然函数的cross-validation 算法，  但我的似然函数除了有带宽h，还有另一个参数阈值un，问题如下：
we use leave-one-out cross-validation to select them here. The optimal values for h and un are then obtained by maximizing

CV (h, un) = sum(  log f ( Yi ;   α^  (xi) ),
where α^ (xi) is the fitted value with the i th αbservation removed and using bandwidth and threshold combination (h, un).

大家有没有这种问题的程序，或者知道同类型问题的包，求解答，不甚感激哈。