帮助我改进我的引导程序

请考虑以下代码:

require(Hmisc)
num.boots <- 10
data <- rchisq(500, df = 5) #generate fake data

#create bins
binx <- cut(data, breaks = 10)
binx <- levels(binx)
binx <- sub("^.*\\,", "", binx)
binx <- as.numeric(substr(binx, 1, nchar(binx) - 1))

#pre-allocate a matrix to be filled with samples
output <- matrix(NA, nrow = num.boots, ncol = length(binx)) 

#do random sampling from the vector and calculate percent
# of values equal or smaller to the bin number (i)
for (i in 1:num.boots) {
    walk.pair.sample <- sample(data, size = length(data), replace = TRUE)
    data.cut <- cut2(x = walk.pair.sample, cuts = binx)
    data.cut <- table(data.cut)/sum(table(data.cut))
    output[i, ] <- data.cut
}

#do some plotting
plot(1:10, seq(0, max(output), length.out = nrow(output)), type = "n", xlab = "", ylab = "")

for (i in 1:nrow(output)) {
    lines(1:10, output[i, 1:nrow(output)])
}

#mean values by columns
output.mean <- apply(output, 2, mean)
lines(output.mean, col="red", lwd = 3)
legend(x = 8, y = 0.25, legend = "mean", col = "red", lty = "solid", lwd = 3)

我想知道是否可以为boot:boot()函数提供一个长度为n>1的函数作为其输出?有可能吗?

这是我无力的尝试,但我一定做错了什么。

require(boot)
bootstrapDistances <- function(data, binx) {
    data.cut <- cut2(x = data, cuts = binx)
    data.cut <- table(data.cut)/sum(table(data.cut))
    return(data.cut)
}

> x <- boot(data = data, statistic = bootstrapDistances, R = 100)
Error in cut.default(x, k2) : 'breaks' are not unique

我真的不明白为什么 Hmisc::cut2() 在中工作不正常 boot() 打电话,但当我打电话给 for() 循环(参见上面的代码)。是我的逻辑 bootstrapDistances() 功能可行 BoT() ?任何提示都非常感谢。

编辑:。

aniko建议我这样修改我的函数,包括一个索引。在阅读boot()的文档时,我不清楚它是如何工作的,这解释了为什么函数可能不工作。以下是Aniko建议的新功能:

bootstrapDistances2 <- function(data, idx, binx) { 
  data.cut <- cut2(x = data[idx], cuts = binx) 
  data.cut <- table(data.cut)/sum(table(data.cut)) 
  return(data.cut) 
} 

但是,我设法产生了一个错误,我仍在研究如何删除它。

> x <- boot(data = data, statistic = bootstrapDistances2, R = 100, binx = binx)
Error in t.star[r, ] <- statistic(data, i[r, ], ...) : 
  number of items to replace is not a multiple of replacement length

重新启动R会话(也尝试了另一个版本2.10.1)后,它似乎工作正常。