我正在研究通过最小化平方和来估计参数的问题。需要的方程是:
我optim
在包装中使用stats
:
# provide the values for a test dataset (the y estimated should be 1.41)
pvector <- c(0.0036,0.0156,0.0204,0.0325,0.1096,0.1446,0.1843,0.4518)
zobs <- c(0.0971,0.0914,0.1629,0.1623,0.3840,0.5155,0.3648,0.6639)
# make input of the C value
c <- function(y){
gamma(y)/((gamma(y*(1-pvector)))*(gamma(y*pvector)))
}
# make input of the gamma function
F1 <- function(y){
f1 <- function(x){
c*(1-x)^(y*(1-pvector)-1)*x^(y*pvector-1)
}
return (f1)
}
# integration over x
int <- function(y){
integrate (F1(y),lower =0.001, upper =1)
}
# write the function for minimization
f2 <- function(y) {
sum ((int-zobs)^2)
}
# minimization
optim(0.01,f2, method = "Brent", lower =0, upper = 1000, hessian=TRUE)
这没有用。我收到以下错误消息:
int - zobs 中的错误:二元运算符的非数字参数
我认为函数的编写方式肯定存在根本性的错误。