From: Minh Tran <mtgred@...>
Date: 2008-07-02T22:25:31+09:00
Subject: Re: Arithmetic oddity

I tried with

s = l.map {|e| (e**2).to_s.to_f}

instead of

s = l.map {|e| e**2}

and it now works.

It doesn't look very elegant though to need such kind of hacking to make 
it base operator to work as expected.



Eleanor McHugh wrote:
> On 2 Jul 2008, at 13:48, Minh Tran wrote:
>> It still look odd as the value in s[2] is 2.0 which doesn't seems to
>> have any rounding problem.
>>
>> In any case is there any workaround to fix get the condition as true ?
> 
> Floating point representations are in many cases (such as irrational
> numbers like square root of 2) only approximations to a given value,
> you therefore have to test that the value is accurate to a given
> precision (number of significant digits). For example, given:
> 
>   x = (1.0 + 1.0) ** 0.5
> 
> you could write your test as:
> 
>   (x ** 2.0).between?(1.9999, 2.0001)
> 
> 
> Ellie
> 
> Eleanor McHugh
> Games With Brains
> http://slides.games-with-brains.net
> ----
> raise ArgumentError unless @reality.responds_to? :reason

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