Karim Belabas on Wed, 18 Jul 2012 14:57:42 +0200 |
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Re: formal ellinit |
* Bill Allombert [2012-07-17 14:07]: > On Tue, Jun 12, 2012 at 11:53:40PM +0200, Karim Belabas wrote: > > * Bill Allombert [2012-06-11 14:06]: > > > I found a way to do a formal ellinit which is sometimes useful: > > > > > > ? a6;a4;a3;a2;a1;E=ellinit([a1,a2,a3,a4,a6],1); > > > ? ## > > > *** last result computed in 0 ms. > > > > > > This is useful because the more straightforward > > > a1;a2;a3;a4;a6;ellinit([a1,a2,a3,a4,a6],1); > > > does not really work (much much slower). > > > > I committed a workaround for the original problem in master: > > This is very useful, thanks. > However your work around only seems to work in char 0, 2 and 3. > > ? E=ellinit([a1,a2,a3,a4,a6]*Mod(1,5)) > *** ellinit: the PARI stack overflows ! > current stack size: 32000000 (30.518 Mbytes) A problem in isinexactall(): one "simple" coefficient in the wrong degree was enough to decide that the whole polynomial was "simple" and that the naive RgX_gcd_simple() was sufficient. Fixed in master. Thanks ! K.B. -- Karim Belabas, IMB (UMR 5251) Tel: (+33) (0)5 40 00 26 17 Universite Bordeaux 1 Fax: (+33) (0)5 40 00 69 50 351, cours de la Liberation http://www.math.u-bordeaux1.fr/~belabas/ F-33405 Talence (France) http://pari.math.u-bordeaux1.fr/ [PARI/GP] `