==在R中，具有.Machine $ double.eps精度 [英] == in R, with .Machine$double.eps accuracy

问题描述

在R中，我不得不转换诸如以下的易读代码有点烦人:

In R, I find it a bit annoying to have to transform easy-to-read code like:

if (det(A) == 1)       # not always working because of floating point precision
    ...

到

if (abs(det(A) - 1) < .Machine$double.eps)     # working but bad for readability
    ...

问题:R中是否有内置运算符可以测试值是否等于".Machine$double.eps错误"?像这样的东西:

Question: is there a built-in operator in R that tests if values are equal "up to a .Machine$double.eps error"? Something like:

if (det(A) ==~ 1)       # TRUE even if det(A) = 1 + 1e-17
    ...

推荐答案

一种方法是像这样声明一个函数%=~.

One way would be to declare a function %=~ like this.

`%=~%` <- function(x, y, tol = .Machine$double.eps^0.5) abs(x - y) < tol

2 %=~% (2+1e-15)
#[1] TRUE

然后可以使用您选择的公差tol.

You could then use the tolerance tol of your choice.

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