Hi John (cc: sage-devel),
On Tue, May 6, 2008 at 12:58 AM, John Cremona <[EMAIL PROTECTED]> wrote:
> That certainly looks like a bug in my code. Please can you send me a
> complete example so I can track it down?
Please see
http://trac.sagemath.org/sage_trac/ticket/3111
> You may well be the first person to use this code for real (as opposed
> to made up examples for testing), which is *great*, as there are bound
> to be bugs, and I really want to fix them!
I'm finding your code extremely useful for some work I'm doing related
to Heegner points right now. It's especially useful that I can get
group structures
and fast point counts over non prime fields. I tried to do similar
calculations a
year ago for a course I was teaching and it was a *major* pain since none of
your code existed then. So thanks!!
> John
>
> PS
> I tend to put in assert() statements when testing and take them out
> when I think code is bug-free, but it sounds like it's a good thing
> this one is left in.
assert is an *excellent* thing to use, and we should all use it much more.
One of the great things about assert in Python is that if you run Python
with a certain command line option it magically simply ignores all
assert statements, so they cost nothing. I almost never use asserts
in my code, which is stupid -- we should all be using them way way more.
By the way, Allan Steel uses asserts in his Magma C code way
more than anyone else I've ever seen, and look where it has
got him. :-)
-- William
>
> 2008/5/6 William Stein <[EMAIL PROTECTED]>:
>
>
> > John,
> >
> > I've been computing E(GF(q)) a lot today and keep seeing this:
> >
> >
> >
> > Traceback (click to the left for traceback)
> > ...
> > AssertionError
> >
> > Traceback (most recent call last):
> > File "<stdin>", line 1, in <module>
> > File
> "/Users/was/papers/research/sage_notebook/sage_notebook/worksheets/admin/4/code/570.py",
> > line 6, in <module>
> > scan_lame(E,Integer(67))
> > File
> "/Users/was/build/sage/local/lib/python2.5/site-packages/sympy/plotting/",
> > line 1, in <module>
> >
> > File
> "/Users/was/papers/research/sage_notebook/sage_notebook/worksheets/admin/4/code/569.py",
> > line 10, in scan_lame
> > G, phi = Emod.abelian_group()
> > File
> "/Users/was/build/sage/local/lib/python2.5/site-packages/sage/schemes/elliptic_curves/ell_finite_field.py",
> > line 1121, in abelian_group
> > P2,n2=generic.merge_points((P2,n2),(Q,m),operation='+');
> > File
> "/Users/was/build/sage/local/lib/python2.5/site-packages/sage/groups/generic.py",
> > line 1127, in merge_points
> > assert multiple(g1,n1,operation=operation) == identity
> > AssertionError
> >
> >
> >
> > --
> > William Stein
> > Associate Professor of Mathematics
> > University of Washington
> > http://wstein.org
> >
>
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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