两个值看似相同，但是matlab说 [英] two values are seemingly the same, yet matlab says the aren't

问题描述

我无法解释这一点.我有两个具有相同值的变量，但是它们并不相同.谁能告诉我我在这里想念的东西吗?

I cannot explain this. I have two variables having the same value, yet they are not identical. Can anybody tell me what I'm missing here?

>> y
y =
3.4000
>> x
x =
3.4000
>> y==x
ans =
 0
>> whos x
 Name      Size            Bytes  Class     Attributes
 x         1x1                 8  double              
>> whos y
 Name      Size            Bytes  Class     Attributes
 y         1x1                 8  double   

这真的让我感到困惑，我发誓这不是在开玩笑.

It's really puzzling for me and I swear it's not a joke.

推荐答案

这是因为浮点精度.试试

It's because of floating point precision. Try

format long g

，然后再次查看x和y.最好将x-y与一些较小的公差值进行比较，而不是对浮点数进行相等性测试

and then look at x and y again. It's better to compare x-y to some small tolerance value rather than doing an equality test on floating point numbers

这篇关于两个值看似相同，但是matlab说的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！