num/denom v's double (was: Re: [LAD] [ANN] LV2 beta3)

Dave Robillard drobilla at
Sat May 26 17:05:45 UTC 2007

On Fri, 2007-05-11 at 18:24 +0100, Steve Harris wrote:
> On 11 May 2007, at 15:07, Fons Adriaensen wrote:
> > On Fri, May 11, 2007 at 03:33:04PM +0200, Lars Luthman wrote:
> >
> >> That sounds like a good argument for two ints to me. Although  
> >> you'd have
> >> to do a lot better than double if you wanted to represent irrational
> >> numbers in binary form. =)
> >
> > Two 32-bit ints can represent (the non-integer part of) most (not all)
> > irrational values to better precision than a double. The algo to find
> > them is a bit mysterious but very simple. Simple example: 355/113 is
> > equal to pi with a relative error of less than 1e-7, not bad for two
> > 3-digit numbers. It's not difficult to find two 32-bit ints that would
> > be better than a double.

So, what's the verdict on this?

Don't want to fall into the perpetual beta with known issue trap, I'd
like to fix the sample rate issue and crank out another beta ASAP..

I'm skeptical we'd ever actually see a plugin that would use rational
sample rate, so I vote double unless:

- rational is required for perfect video sync over long time frames

- someone can provide a concrete example of a realistic plugin that
would require/benefit from rational


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