当setMethod(或setGeneric)中的参数太多时,R挂起

Question

基本上,当setMethodor或(setGeneric)中存在许多参数时,它的工作速度非常慢.

这是一个基本的例子:

setClassUnion(name = "mNumeric", members = c("missing", "numeric"))
setClass(Class = "classA", representation = representation(ID = "character"))

setGeneric("foo", function(r, i, ..., m = 1, D = 1, U = 999, K = 0.005, 
                           E1 = -5, E2 = 5, E3 = 1, E4 = 1, E5 = 1, E6 = 1,
                           A1 = -5, A2 = 5, A3 = 1, A4 = 1, A5 = 1, A6 = 1)
                  {standardGeneric ("foo")})

setMethod(f = "foo", 
  signature = c(r = "ANY", i = "classA", m = "mNumeric", D = "mNumeric", 
                U = "mNumeric", K = "mNumeric", E1 = "mNumeric", E2 = "mNumeric",
                E3 = "mNumeric", E4 = "mNumeric", E5 = "mNumeric", E6 = "mNumeric", 
                A1 = "mNumeric", A2 = "mNumeric", A3 = "mNumeric", A4 = "mNumeric", 
                A5 = "mNumeric", A6 = "mNumeric"),
  function(r, i, ..., m, D, U, K, E1, E2, E3, E4, E5, E6, A1, A2, A3, A4, A5, A6)
    {print("Function can made it here..")})

#Program hangs after the following code. (at least five minutes)
foo(r = 1, i = new("classA", ID = "ID1"))

我发现这与班级无关.你可以把一个numeric类放进去r,它会做同样的事情.如果我削减参数的数量,它将起作用.

我怀疑它尝试" to find an inherited method for function ‘foo’ for signature ‘"numeric", "classA", "missing", ...",这导致R挂起.这里是对这个主题的一个很好的讨论.

因为如果我使用较少的参数运行相同的代码,它会工作

setGeneric("foo", function(r, i, ..., m = 1, D = 1, U = 999, K = 0.005, 
                           E1 = -5, E2 = 5, E3 = 1, E4 = 1)
          {standardGeneric ("foo")})

setMethod(f = "foo", 
  signature = c(r = "ANY", i = "classA", m = "mNumeric", D = "mNumeric", 
                U = "mNumeric", K = "mNumeric", E1 = "mNumeric", E2 = "mNumeric",
                E3 = "mNumeric", E4 = "mNumeric"),
  function(r, i, ..., m, D, U, K, E1, E2, E3, E4)
  {print("Function can made it here..")})

foo(r = 1, i = new("classA", ID = "ID1"))

为什么会这样？任何想法将不胜感激.

Answer 1

我有类似的问题。S4似乎是所有可能的签名组合。这会减慢速度。解决方案是签名中的元素尽可能少。

您可以在这里找到详细信息https://stat.ethz.ch/pipermail/r-devel/2015-May/071092.html