From: Robert Klemme <shortcutter@...>
Date: 2008-07-02T23:01:41+09:00
Subject: Re: Arithmetic oddity

2008/7/2 Minh Tran <mtgred@gmail.com>:
> 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.

But it works only accidentally!  This is likely to break soon again.

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

No, no, no!  The operator works as expected.  There is even an IEEE
standard defining how floating point math has to behave. You must
*never* rely on == when doing float math.  In this case you rather
need to do either of these

- resort to decimal math with BigDecimal

- define equality as a max difference ("epsilon") between two float
values and test that

Kind regards

robert

-- 
use.inject do |as, often| as.you_can - without end