无法在 R 中并行化具有多个参数的函数

Question

我尝试并行化一个简单的函数，该函数将两个数字相加并在库中R使用时打印结果。这是我的代码：mclapplyparallel

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library(doParallel)\nt = list(list(1,1),list(2,2),list(3,3))\nf <- function (a,b){\n    print(a + b)\n}\nmclapply(t,f)\n

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但它返回错误：

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Warning message in mclapply(t, f):\n\xe2\x80\x9call scheduled cores encountered errors in user code\xe2\x80\x9d\n

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[[1]]\n[1] "Error in print(a + b) : argument \\"b\\" is missing, with no default\\n"\nattr(,"class")\n[1] "try-error"\nattr(,"condition")\n<simpleError in print(a + b): argument "b" is missing, with no default>\n\n[[2]]\n[1] "Error in print(a + b) : argument \\"b\\" is missing, with no default\\n"\nattr(,"class")\n[1] "try-error"\nattr(,"condition")\n<simpleError in print(a + b): argument "b" is missing, with no default>\n\n[[3]]\n[1] "Error in print(a + b) : argument \\"b\\" is missing, with no default\\n"\nattr(,"class")\n[1] "try-error"\nattr(,"condition")\n<simpleError in print(a + b): argument "b" is missing, with no default>\n

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有人可以告诉我我在这里做错了什么吗？

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我尝试搜索如何并行运行具有多个参数的函数，但没有找到答案。

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Answer 1

mclapply正在为列表中的每个元素调用该函数，该列表本身就是一个列表。因此，每次调用该函数时，您都会向其传递一个列表，而不是其他任何内容。您需要解压函数中的列表：

library(doParallel)
t = list(list(1,1),list(2,2),list(3,3))
f <- function (a){
  print(a[[1]] + a[[2]])
}
mclapply(t,f)