Bill Allombert on Wed, 03 Feb 2010 18:23:12 +0100 |
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Re: ellap hangs on a large-ish prime |
On Mon, Feb 01, 2010 at 09:50:24PM -0400, Jeremy Porter wrote: > Greetings, > > In iteratively computing values of ellap(E,P) for the curve E = > ellinit([0,0,1,-1,0]) for primes P of increasing size, I noticed that when P > = 2486152157 my iteration would hang. Primes in a similar range (i.e., > nextprime(P+1) = 2486152159) are computed in well under a second, however I > left this value of P to compute overnight without result. > > I initially noticed this when using libpari in a C program, then confirmed > it with the GP calculator. An example follows: > > E = ellinit([0,0,1,-1,0]); > P = 2486152157; > isprime(P) > ellap(E, nextprime(P+1)) > ellap(E, P) Hello Jeremy, This issue should be fixed in PARI 2.3.5 which will be released on Friday. A prerelease is available at <http://pari.math.u-bordeaux.fr/~bill/pari-2.3.5-pre3.tar.gz> for testing. Thanks a lot to have reported this problem! Cheers, Bill.