重复使用其输出作为自己输入的 R 函数 [英] R function that uses its output as its own input repeatedly

问题描述

给定 R 函数 auto(如下)，我想知道是否有可能从 psfor 循环输出的第二次运行开始code> 用作 pr?

Given R function auto (below), I was wondering if it might be possible that from the second run of the for loop output of ps be used as pr?

例如，如果循环要进行 3 次(即 length(n) = 3)，则在循环的第一次运行中使用 pr照原样，但是从第二次运行开始，之前运行的 ps(即 ps(x))的结果取代了 pr最多length(n)个.

For example, if loop is going to go 3 times (i.e., length(n) = 3), then in the first run of the loop pr is used as is, but from the second run the result of ps (i.e., ps(x)) from the run before takes the place of pr up to the number of length(n).

所以，在第一次运行 for 循环之后，每次，来自前一次运行的 ps(x) 都扮演了 pr 为下一次运行.我的最终目标是将这种方式得到的最终ps曲线.

So, after the first run of the for loop, each time, ps(x) from the previous run takes the role of pr for the next run. My ultimate goal is to curve the final ps obtained in this manner.

auto <- function(n, dat){

for(i in 1:length(n)){           
 pr = function(x) dbeta(x, 1, 1)
 lk = function(x) dbinom(dat[i], n[i], x) # So, here first `n = 100` and 
 ps = function(x) pr(x)*lk(x)             # `dat = 55` will go thru first 
  }                                       # round of the loop and produce
 curve(ps)                                # a `ps`. But in the second run of
}                                         # the loop, the `ps` just
# Example of use:                         # produced will be used as `pr`
auto(n = c(100, 50), dat = c(55, 60) )    # for `n = 50` and `dat = 60`
                                          # to produce a new `ps`.

推荐答案

不确定我是否完全理解问题.我在 for 循环中添加了一个 if 语句来检查它是否是第一次迭代.如果是，它将通过您的原始语句定义 pr.如果不是，则通过 pr(x) * 由 i-1 子集的前一次迭代的 lk(x) 函数定义它.不过我确定我在这里遗漏了一些东西..

Not sure I fully understand the problem. I added an if statement in the for loop to check if its the first iteration. If it is, it would define pr, by your original statement. if not, define it by pr(x) * the lk(x) function of the previous iteration which subsets by i-1. I'm sure I'm missing something here though..

我也很困惑 x 输入的来源.

I'm also confused where the x input is coming from.

auto <- function(n, dat){

  for(i in 1:length(n)){
    if(i == 1){pr = function(x) dbeta(x, 1, 1)} else{pr = function(x) dbeta(x, 1, 1) * function(x) dbinom(dat[i-1], n[i-1], x)}
    lk = function(x) dbinom(dat[i], n[i], x)
    ps = function(x) pr(x)*lk(x)
  }
  curve(ps)
}
# Example of use:
auto(n = c(100, 50), dat = c(55, 60) )

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