如何在 R 中显示并行计算中的代码进度? [英] How to show the progress of code in parallel computation in R?

问题描述

我现在正在处理一个大型数据集，有些函数可能需要几个小时来处理.我想知道如何通过进度条或数字(1,2,3,...,100)显示代码的进度.我想将结果存储为具有两列的数据框.这是一个例子.谢谢.

I am now dealing with a large dataset and some functions may take hours to process. I wonder how I can show the progress of the code through a progress bar or number(1,2,3,...,100). And I want to store the result as a data frame with two columns. Here is an example. Thanks.

require(foreach)
require(doParallel)
require(Kendall)

cores=detectCores()
cl <- makeCluster(cores-1)
registerDoParallel(cl)

mydata=matrix(rnorm(8000*500),ncol = 500)
result=as.data.frame(matrix(nrow = 8000,ncol = 2))
pb <- txtProgressBar(min = 1, max = 8000, style = 3)

foreach(i=1:8000,.packages = "Kendall",.combine = rbind) %dopar%         
{
  abc=MannKendall(mydata[i,])
  result[i,1]=abc$tau
  result[i,2]=abc$sl
  setTxtProgressBar(pb, i)
}
close(pb)
stopCluster(cl)

然而，当我运行代码时，我没有看到任何进度条出现，结果也不对.有什么建议吗?谢谢.

However, when I run the code, I did not see any progress bar showing up and the result is not right. Is there any suggestion? Thanks.

推荐答案

doSNOW 包支持进度条，而 doParallel 不支持.这是在示例中放置进度条的一种方法:

The doSNOW package has support for progress bars, while doParallel does not. Here's a way to put a progress bar in your example:

require(doSNOW)
require(Kendall)
cores <- parallel::detectCores()
cl <- makeSOCKcluster(cores)
registerDoSNOW(cl)
mydata <- matrix(rnorm(8000*500), ncol=500)
pb <- txtProgressBar(min=1, max=8000, style=3)
progress <- function(n) setTxtProgressBar(pb, n)
opts <- list(progress=progress)
result <- 
  foreach(i=1:8000, .packages="Kendall", .options.snow=opts,
          .combine='rbind') %dopar% {
    abc <- MannKendall(mydata[i,])
    data.frame(tau=abc$tau, sl=abc$sl)
  }
close(pb)
stopCluster(cl)

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