Haskell中的高精度浮点数？ [英] High precision floating point numbers in Haskell?

问题描述

我知道Haskell具有原生数据类型，它允许你有非常大的整数，例如

 >>让x = 131242358045284502395482305 
>> x 
 131242358045284502395482305 
  

按预期工作。我想知道是否有一个类似的大精度浮点本地结构，我可以使用，所以像

 >> ;让x = 5.0000000000000000000000001 
>> x 
 5.0000000000000000000000001 
  

是可能的。如果我在Haskell中输入它，如果超过15个小数位（双精度），它会截断为5。 解决方案

取决于您正在寻找什么：

• 浮动和 Double - 几乎所有你知道的和来自Floats和Doubles的所有其他语言的Love。
haskell.org/packages/archive/base/latest/doc/html/Prelude.html#t:Rationalrel =noreferrer> Rational 这是比率 整数 s

• FixedPoint - 此包提供任意大小的定点值。例如，如果您想要一个由64个整数位和64个小数位表示的数字，您可以使用 FixedPoint6464 。如果你想要一个1024位整数和8位小数的数字，那么使用 $（mkFixedPoint 1024 8）来产生类型 FixedPoint1024_8 数字包 - 非常酷。
b $ b

I know Haskell has native data types which allow you to have really big integers so things like

>> let x = 131242358045284502395482305
>> x
131242358045284502395482305

work as expected. I was wondering if there was a similar "large precision float" native structure I could be using, so things like

>> let x = 5.0000000000000000000000001
>> x
5.0000000000000000000000001

could be possible. If I enter this in Haskell, it truncates down to 5 if I go beyond 15 decimal places (double precision).

解决方案

Depending on exactly what you are looking for:

• Float and Double - pretty much what you know and "love" from Floats and Doubles in all other languages.
• Rational which is a Ratio of Integers
• FixedPoint - This package provides arbitrary sized fixed point values. For example, if you want a number that is represented by 64 integral bits and 64 fractional bits you can use FixedPoint6464. If you want a number that is 1024 integral bits and 8 fractional bits then use $(mkFixedPoint 1024 8) to generate type FixedPoint1024_8.
• EDIT: And yes, I just learned about the numbers package mentioned above - very cool.

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