Re: [boost] rational with finite precision

From: Daryle Walker (darylew_at_[hidden])
Date: 2004-12-20 19:52:30

On 12/11/04 5:03 AM, "Andras Erdei" <aerdei_at_[hidden]> wrote:

[The problem: It occurs when using boost::rational with limited-size integer
types, typically the built-in ones.  A basic rational operation may have the
numerator and/or denominator overflowing, leading to a garbage "sideflowed"
result, even though the true result is between representable values.]

[SNIP]
> fixing rational<> to work with finite precision integers
> so that for calculations like the above we get the best
> representable approximation (in this case 3197/1540 =
> 2.076, precise to 7 digits) is pretty straightforward
> -- the gcd() function implicitly calculates all
> representable approximations -- but would require
> rewriting the whole class

I would like to see precise directions of the algorithms that give the
closest representable result (that have to try avoiding internal overflow).

-- 
Daryle Walker
Mac, Internet, and Video Game Junkie
darylew AT hotmail DOT com