Karim BELABAS on Thu, 18 Apr 2002 14:32:51 +0200 (MEST)


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Re: GP algdep() bug?


On Wed, 17 Apr 2002, Michael Somos wrote:
> I am using a CVS version a few weeks old and getting expected result :
>
> ? algdep(sin(1),2)
> %1 = 15022667*x^2 - 9294001*x - 2816519
[...]
> but using the up-to-the-minute CVS version on another platform I get :
[...]
> ? algdep(sin(1),2)
> %1 = 20837219769947.44558715315281
>
> Could something have changed in the last few weeks for 'algdep()'?

The current CVS version uses PSLQ instead of LLL / HJLS to find integral
relations [ undocumented for now, the code is in a _very_ unstable state ].

The output means that PSLQ failed and any relation (in algdep context: a
minimal polynomial) has height > 20837... I believe the current output is
more useful than the former one.

Thanks for testing the CVS code !

    Karim.
-- 
Karim Belabas                    Tel: (+33) (0)1 69 15 57 48
Dép. de Mathematiques, Bat. 425  Fax: (+33) (0)1 69 15 60 19
Université Paris-Sud             Email: Karim.Belabas@math.u-psud.fr
F-91405 Orsay (France)           http://www.math.u-psud.fr/~belabas
--
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