opalcat
请问在用下面程序运算的时候,为什么会出现无法用初始参数评估函数的错误,还有warning message?可能的原因有哪些呢?我换了好几次初始值也不行
for (Nu in 3:203) {
fnk=function(x){
i=1:Nu
n=204
u= y[n-Nu]
a=x[1]
b=x[2]
Nu*log(b)+(1+1/a)*sum(log(1+(a/b)*(y[n-Nu+i]-u)))
}
constrOptim(c(1,1),fnk,NULL,ui=rbind(c(1,0),c(0,1)),ci=c(0.1,0.1))
x<- (constrOptim(c(1,1),fnk,NULL,ui=rbind(c(1,0),c(0,1)),ci=c(0.1,0.1))$par)
a<-cat(x[1], “\n”) }
1.078851
0.7822457
0.5867037
0.4487596
0.4834112
0.2606233
0.1429819
0.2088161
0.2058418
0.2961009
0.3200839
0.3223586
0.4049518
0.5225909
0.6112027
0.7363992
0.5995625
0.7439314
0.759
错误在optim(theta.old, fun, gradient, control = control, method = method, :
无法用初始参数来评估函数
此外: Warning messages:
1: 产生了NaNs in: log(x)
2: 产生了NaNs in: log(x)
3: 产生了NaNs in: log(x)