如何在R中派生进程 [英] How to fork processes in R

问题描述

我试图了解R的多核软件包所实现的分叉系统.包示例为:

I'm trying to understand the forking system implemented by R's multicore package. The package example is:

p <- fork()
if (inherits(p, "masterProcess")) {
  cat("I’m a child! ", Sys.getpid(), "\n")
  exit(,"I was a child")
}
cat("I’m the master\n")
unserialize(readChildren(1.5))

，但在R交互式控制台中粘贴后似乎无效.有没有人举过在R的多核或并行包中使用fork()的示例?

but it doesn't seem to work when pasted in the R interactive console. Does anyone have an example of using fork() with R's multicore or parallel packages?

推荐答案

多核软件包为我工作"中的fork示例；尝试example(fork).仅在非Windows系统上支持fork.

The fork example in the multicore package 'works for me' ; try example(fork). fork is only supported on non-Windows systems.

我认为parallel中的等效函数是mcparallel()进行派生然后评估表达式，而mcollect()则在完成后检索结果.所以

I think the equivalent functions in parallel are mcparallel() to fork and then evaluate an expression, and mcollect() to retrieve the result when done. So

id = mcparallel({ Sys.sleep(5); TRUE })

立即返回，但进程正在运行，并且

returns immediately but the process is running, and

mccollect(id)

将在5秒后返回TRUE.除了分叉进程和主进程之间的集合外，没有其他通信.使用例如套接字来实现双向通信将是有趣的，并且不会带来太大的挑战.

will return TRUE after 5 seconds. There is no communication other than the collection between the forked and master process; it would be interesting and not too challenging to implement two-way communication using, e.g., sockets.

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