Bill Allombert on Sat, 17 Dec 2016 17:16:15 +0100 |
[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]
Re: Ratpoint |
On Sat, Dec 17, 2016 at 03:33:54PM +0000, John Cremona wrote: > On 17 December 2016 at 14:40, Bill Allombert > <Bill.Allombert@math.u-bordeaux.fr> wrote: > > On Sat, Dec 17, 2016 at 08:11:27AM +0000, Jenn Macleod wrote: > >> Does anybody have a Pari implementation of Michael Stoll's ratpoint.c code? > >> > >> This would be of great use in my doodlings. > > > > Denis Simon descent code include one: > > <http://www.math.unicaen.fr/~simon/ellQ.gp> > > function ratpoint. > > > > This is misleading. Denis Simon's code needs a function to find > solutions to y^2=f(x) where f is integral of degree 3 or 4, and he > provides a function called ratpoint() to do this. It is *not* the > same as Michael Stoll's independent C program of that name. Stoll's > program ratpoints.c (which he developed from old code by Elkies) is > more general in several ways (deg(f) essentially arbitrary) and also > probably much faster. This is very true. However Denis functions is not limited to degree 3/4 polynomials. Cheers, Bill.