From: Marnen Laibow-Koser <marnen@...>
Date: 2009-11-15T10:41:15+09:00
Subject: Re: Trajectories

Eleanor McHugh wrote:
> On 15 Nov 2009, at 01:19, Marnen Laibow-Koser wrote:
>>
>> IEEE floats have no advantages that I can see and huge  
>> disadvantages.  I
>> just don't see them as being even slightly appropriate or useful for
>> math.
> 
> Because often expressing non-integral values as floating-point in code
> better represents intent than using fixed-point math, 

True, perhaps.  Ward was doing fixed-point currency, so expressing 
amounts as pennies is semantically clear.

But that's where BigDecimal comes in.  It's clearly a floating-point 
number, but it's actually accurate.  Semantically clear, numerically 
precise.  What more could you want? :)

> and unless the
> latter will have a performance or accuracy advantage for a given
> problem I consider semantic simplicity to be my primary design
> criterion.

BigDecimal is no less semantically simple than Float (particularly when 
coupled with Ruby's operator overloading), and it will always have an 
accuracy advantage for any conceivable problem.

> 
> That said I agree that floating-point sucks and that many programmers
> use it in a carefree manner that suggests they're unaware of the
> limitations it imposes.
> 
> 
> Ellie
> 

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
Posted via http://www.ruby-forum.com/.