bad error message in SupersingularModule constructor

[williamstein]

sage: SupersingularModule(15)
Traceback (most recent call last):
...
ValueError: order of finite field must be a prime power

The error message should say something like:

NotImplementedError: supersingular module of non-prime level not yet implemented

Component: modular forms

Issue created by migration from https://trac.sagemath.org/ticket/4307

[aghitza]

comment:2

Having looked at the code in ssmod.py, it seems to me that any nontrivial functionality is only implemented for level 1 at the moment. Two things that I tried: dimension() and hecke_matrix().

The attached patch raises ValueErrors if the characteristic is not prime or if the level is not coprime to the characteristic, and a NotImplementedError if the level is > 1.

Extending the functionality in ssmod.py to general levels is right up my alley, so I'll look into doing it in the near future. The code could also use more documentation and tests.

[sagetrac-mabshoff]

comment:3

Alex,

please add doctests that show the new behavior to the not yet existing class SupersingularModule(hecke.HeckeModule_free_module) docstring.

Cheers,

Michael

[aghitza]

comment:4

Attachment: trac4307-ssmod_init.patch.gz

Yes. Done, and replaced the patch.

[craigcitro]

comment:5

Looks good.

[sagetrac-mabshoff]

comment:6

Merged in Sage 3.2.alpha1