From: Eleanor McHugh <eleanor@...>
Date: 2008-07-02T22:57:15+09:00
Subject: Re: Arithmetic oddity

On 2 Jul 2008, at 14:25, Minh Tran wrote:
> 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.

And that method also imposes considerable runtime cost. As I said, use  
a comparison such as (2.0).between?(1.99999, 2.00001) as that's:

a. computationally much less expensive;
b. what a floating-point '==' actually means.

Also you should probably read http://en.wikipedia.org/wiki/Floating_point 
  and then do some further research into floating point number  
representations to gain some deeper insight into what is actually  
meant by 2.0 when it's converted into binary format. It may inspire  
you to more elegant ways of solving whatever problem it is that you're  
working on.


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net
----
raise ArgumentError unless @reality.responds_to? :reason