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
>
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-- 
William Stein
Professor of Mathematics
University of Washington
http://wstein.org

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