From: Roger Pack <rogerpack2005@...>
Date: 2009-02-22T07:08:18+09:00
Subject: Re: floating point rounding error?

> 1. existing code might be broken

True

> 2. efficiency (Float is faster than BigDecimal)

Can't disagree with that.


> 3. standards (AFAIK the Float implementation is backed by an ISO
> standard while I am not sure whether this is the case for BigDecimal).

True.

> 4. limited use: while your particular example will work as you expect,
> BigDecimal is still not a real number (in math terms) but still a
> rational number => rounding errors for other numbers will be introduced
> when switching from Float to BigDecimal by default.

The only real benefit of it is that it won't bite "as often," for better 
or worse.
This is a learning curve that could hit you at the edges [adding 
extremely small and extremely large numbers, for example] and not during 
normal day use :)

One "almost good" answer would be to have ruby output float to strings 
by default with enough precision to be able to recreate the original.


Thoughts?
-=r
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