lcalc.analytic_rank fails

[Barinder Banwait]

MWE:

sage: A = -17737878703644595885728157881856/2195118875780412735240966796875

sage: B = 76386743039924534000525642916220282669332545616695170155741184/4818546878807463076444691815463494370294881403446197509765625

sage: E = EllipticCurve([A,B])

sage: lcalc.analytic_rank(E)

This produces "***   overflow in t_INT-->t_INT assignment.Segmentation fault (core dumped), followed by "TypeError: unable to convert '' to an integer". It looks like line 385 of sage/lfunctions/lcalc.py is returning the empty string, i.e., 'rank-compute' is failing to compute, probably because of the overflow.

This elliptic curve comes from Elkies and Klagsbrun's recent paper (https://arxiv.org/abs/2003.00077); it is the rank 20 curve with torsion Z/2Z.

Other info:

OS: Ubuntu 18.04.2 LTS, 64bit

Sage installation: Downloaded and unzipped the top link here: http://www.mirrorservice.org/sites/www.sagemath.org/linux/64bit/index.html

SageMath version 9.0, release date 2020-01-01

Using Python 3.7.3

[Peter Bruin]

Hi Barinder,

On my system I get the same error messages as you (but no segmentation fault). This looks like a bug in PARI.  It also happens with the built-in ellanalyticrank function in PARI:

gp> A = -17737878703644595885728157881856/2195118875780412735240966796875;
gp> B = 76386743039924534000525642916220282669332545616695170155741184/4818546878807463076444691815463494370294881403446197509765625;
gp> E = ellinit([A, B]);
gp> ellanalyticrank(E)
  ***   at top-level: ellanalyticrank(E)
  ***                 ^------------------
  *** ellanalyticrank: overflow in t_INT-->ulong assignment.

Do you want to file a PARI bug report?

Best wishes,

Peter

Op woensdag 18 maart 2020 13:36:46 UTC+1 schreef Barinder Banwait:

[Barinder Banwait]

Thanks Peter,

I've just submitted a bug report to PARI/GP - Bug#2212.

Best wishes,
Barinder

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