Andrey, The bundle probably would not be of much use to you, since the function takes as input a Sage multivariate polynomial ring element and outputs a Sage elliptic curve over some field, when all you want is symbolic expression in Weierstrass normal form.
Do you have a copy of the implementation of Nagell's algorithm that you were using? I'm curious as to what is taking so long, since there aren't very many complicated steps; it's mostly basic arithmetic. -Bobby On Thu, May 22, 2008 at 1:11 PM, William Stein <[EMAIL PROTECTED]> wrote: > Andrey, > > Check out the hg bundle attached to this ticket: > http://trac.sagemath.org/sage_trac/ticket/1136 > > Bobby Moretti was implementing code for doing this transformation, but > never finished due to a subtle bug in the transformation maps (he gets the > right cubic but not the right maps). It's possible you'll find the above > bundle > useful (no clue). > > On Thu, May 22, 2008 at 1:04 PM, Andrey Novoseltsev <[EMAIL PROTECTED]> wrote: >> >> I tried to convert >> 2*x*y^2 + 2*a5*t*x*y - x^2 + (2*a4 - 8*t^3)*x - 1, >> where a4, a5, and t are some complex parameters (which I would like to >> keep as undetermined parameters), to Weierstrass normal form using >> Nagell's algorithm and was not quite successful since some steps near >> the end do not finish in a reasonable time (i.e. a few minutes). It is >> possible that I have done some mistakes, since I didn't really tested >> my code yet, but Jacob Lewis told me that this algorithm isn't very >> fast anyway. >> >> As far as I can tell, Sage can do this conversion using MAGMA, but >> only over rational field. Can anyone recommend an efficient way of >> doing such a conversion with symbolic coefficients? Or, perhaps, it is >> already done and I just cannot find the proper function? >> >> Thank you! >> Andrey >> >> >> > > > > -- > William Stein > Associate Professor of Mathematics > University of Washington > http://wstein.org > -- Bobby Moretti [EMAIL PROTECTED] -- Bobby Moretti [EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
