Re: Accessing the ellsea function from Pari 2.4.3 (svn-r11688)

[Hamish Ivey-Law <hlaw@iml.univ-mrs.fr>]

Bill Allombert-3 wrote:
> 
> On Sun, Apr 26, 2009 at 01:46:29PM +0200, Bill Allombert wrote:
>> On Wed, Apr 22, 2009 at 07:44:00AM -0700, Hamish Ivey-Law wrote:
>> > 
>> > Hello Pari-users,
>> > 
>> > I would like to be able to access the function
>> > 
>> >   GEN ellsea(GEN E, GEN p, long EARLY_ABORT)
>> > 
>> > defined in  src/modules/ellsea.c  from the GP command-line.  I know
>> this is
>> > indirectly accessible via the  ellap  command, but I would like to be
>> able
>> > to use the early abort feature which is not accessible via  ellap.  I
>> > thought all I had to do was
>> > 
>> > ? install("ellsea", "GGL")
>> > 
>> > but, although this makes  ellsea  show up in the list of available
>> commands,
>> > when I try to use it I get a bus error:
>> > 
>> > ? ellsea(E, p, 1)
>> >   ***   bug in PARI/GP (Bus Error), please report
>> >   ***   Break loop: type <Return> three times, or Control-d, to go back
>> to
>> > GP)
>> > 
>> > (here  p  is a random 128-bit prime and  E  is a random curve over 
>> FF_p).
>> > 
>> > Does anyone have any idea why this isn't working?  Is the "GGL"
>> prototype
>> > for the  ellsea  function incorrect, or is this actually a problem in
>> Pari? 
>> > In case it matters, I do have the SEAdata package installed.
>> 
>> Hello, thanks for your report,
>> 
>> I have never tested ellsea(,,1) and it is unfortuantely suffering from
>> various
>> bugs. I will try to fix them in the SVN version.
> 
> Hopefully, this should be fixed in SVN version r11693.
> If you still have proble, please post the value of E and p that cause
> the crash.
> 
> Cheers,
> Bill.
> 
> 

It seems to be working fine now.  Thanks Bill!

I have a related offer (possibly should be to pari-devel): I've expanded the
SEAdata package database with the Atkin modular polynomials for primes
between 400 and 500 (I just converted the polynomials from David Kohel's
database: http://echidna.maths.usyd.edu.au/kohel/dbs/PolMod_Atk.tgz).  If
you want them for the SEAdata package, just tell me who to send them to.  If
I'm the only person looking for curves over 512-bit fields then I guess you
might not want to expand the size of the (compressed) SEAdata package by
11MB (the uncompressed package is about 22MB bigger).

Cheers,
Hamish.
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