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From "C. Scott Ananian" <csc...@cscott.net>
Subject Re: [lang] [math] org.apache.commons.lang.math.Fraction class
Date Sat, 29 May 2004 17:55:04 GMT
On Sat, 29 May 2004, Phil Steitz wrote:

> One thing that we might want to consider, given the magnitude of the
> changes, is deprecating this in [lang] and moving it to [math].  That way,
> among other things, the (better) continued fraction implementation in
> [math] could be used in getFraction(double).  The improved gcd and checked
> integer arithmetic methods in the patch might also make good additions to
> o.a.c.math.MathUtils.

I also have an implementation of 'BigFraction' which I can contribute.

> One more thing that we need to verify is that the Knuth algorithms are not
> patented or protected a la _Numerical Recipes_.  Given Knuth's public
> position on software patents, I would be surprised if this were the case;
> but we should verify that neither Knuth's publishers nor _NR_ have claims
> that could encumber the implementations in the patch as derivative work
> prior to committing.

The gcd algorithm was published in 1961, so even if it was patented, the
patent has expired.  The other algorithms don't rise the level of
patentability, they're more in the way of 'implementation hints' (albeit
good ones).
 --scott

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