比较双精度问题 [英] Compare double in VBA precision problem

问题描述

我在Excel VBA中比较2 double时遇到问题

假设我有以下代码：

  Dim a as double 
 Dim b as double 
a = 0.15 
b = 0.01 
  

在b上进行一些操作之后，b现在等于0.6

然而，与double数据类型相关的不精确性给了我头痛，因为

 如果a = b then 
 //这将永远不会触发
 end if $ b $你是否知道如何去除双精度型的尾随不精确度？
 div class =h2_lin>解决方案

您不能比较浮点值的相等性。请参阅有关比较浮点数，讨论如何处理内在错误。

这不是一个简单的比较一个常量的错误余地，除非你知道肯定什么浮动的绝对范围是事先确定的。

I have trouble comparing 2 double in Excel VBA

suppose that I have the following code

Dim a as double
Dim b as double
a = 0.15
b = 0.01

After a few manipulations on b, b is now equal to 0.6

however the imprecision related to the double data type gives me headache because

if a = b then
 //this will never trigger
end if

Do you know how I can remove the trailing imprecision on the double type?

解决方案

You can't compare floating point values for equality. See this article on "Comparing floating point numbers" for a discussion of how to handle the intrinsic error.

It isn't as simple as comparing to a constant error margin unless you know for sure what the absolute range of the floats is beforehand.

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