From: Hal Fulton <hal9000@...>
Date: 2004-05-13T04:15:59+09:00
Subject: Re: Major Addition Bug?

Sean O'Dell wrote:
> On Wednesday 12 May 2004 09:53, ts wrote:
> 
>>>>>>>"S" == Sean O'Dell <sean@celsoft.com> writes:
>>
>>S> raise "false" if ((625.91 + 900.00 + 22.00) != 1547.91)
>>
>> Well, this is well known
> 
> 
> Well known?  I had no idea this bug existed until I wrote a line of code that 
> double-checked the arithmetic from a different app.  I have code all over 
> doing simple arithmetic like this.  Ruby can't add 3 simple numbers?  I don't 
> mean to be disproportionately negative, but that shakes my faith more than a 
> little.  It's just simple arithmetic.  How old is this bug?  When is it 
> getting fixed?

Offhand I'd say this bug dates back to the 1940s, and isn't
getting fixed any time soon.

Seriously, I think it's a matter of trying to store an infinite
number of digits in a finite number of bits.

For a daily life example: How many digits does it take to store
"1/3" exactly?  0.333333...



Hal