> zero.idx = (y==0 $ x== 0)
> sum(zero.idx)/length(y)
[1] 0
> nz.idx = (y !=0 & x !=0)
> gpd.y.fit2 = gpd.tail(y[nz.idx], upper = 0.01,
+ lower = -0.01)
Problem in U.f: Missing value where logical needed: if(sum(xsc < 0) > 0 | a < 0) {
        ll <- NA
} else {
        ll <-  - tempN * log(a) + (1/k - 1) * sum(log(xsc))
}, while calling subroutine sumsno_c
Use traceback() to see the call stack

使用S-PLUS时出现这种情况，请问高手如何解决？是什么原因造成的？请尽量详细的为小弟解答一番。感谢