I tried this example myself and got a similar failure. The error message is not very informative, but what's happening is that PARI-GP (which Simon's 2-descent script uses) is raising an error, because the fundamental units of the number fields coming up in the 2-descent calculation are too big for it to handle.
As Sage relies on launching an external script to do this computation, it doesn't always handle gracefully cases when the external script fails; hence the bizarre error message. David On 5 February 2014 22:53, raman kurdi <[email protected]> wrote: > Thank you very much for your message. > I used simon_two_descent(), for [0,0,0,- 9588522241, 399039337488961], > but Sage says " name 'ans' is not defined". I do not know what 'ans' > is. > Best, > Raman > > > On 2/6/14, William Stein <[email protected]> wrote: >> On Wed, Feb 5, 2014 at 1:06 PM, raman kurdi <[email protected]> >> wrote: >>> Hi Sage, >>> >>> I have some curves with rank at least 4. But I can not compute the >>> rank by Mwrank. I use (' -p 200 -v 0'). >>> Could you please help me? >>> >> >> You might find this example useful, which shows your first curve has rank >> 5. >> >> sage: E = EllipticCurve((0, 0, 0, -591361, 144600625)) >> sage: %time E.simon_two_descent() # output implies rank of 2-selmer is >> 5... >> CPU times: user 744 ms, sys: 40 ms, total: 784 ms >> Wall time: 1.99 s >> (5, >> 5, >> [(281 : 785 : 1), >> (600 : 2405 : 1), >> (625 : 4375 : 1), >> (719 : 9545 : 1), >> (769 : 12025 : 1)]) >> sage: E.root_number() # means rank is odd >> -1 >> >> The algorithm used by simon_two_descent is different than the one in >> mwrank, and works better to get info about the rank in some cases. >> >> William >> >>> Best, >>> Raman >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "sage-support" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/sage-support. >>> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> >> -- >> William Stein >> Professor of Mathematics >> University of Washington >> http://wstein.org >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sage-support" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/sage-support. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
