#16959: p-primary bound for Sha can be improved
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Reporter: wuthrich | Owner:
Type: defect | Status: needs_review
Priority: major | Milestone: sage-6.4
Component: elliptic curves | Resolution:
Keywords: tate-shafarevich, | Merged in:
shark | Reviewers: William Stein
Authors: Chris Wuthrich | Work issues:
Report Upstream: N/A | Commit:
Branch: | 93d45724d5f8451cf3320e1bde08eaf7fae71e67
u/wuthrich/ticket/16959 | Stopgaps:
Dependencies: |
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Comment (by cremona):
I am wondering why Chris removed me from the CC field....in nay case I
received the email when I was added, and now I have written on the ticket
so you cannot get rid of me!
I think this can be fixed by changing lines 66-70 of
sage/libs/cremona/newforms.pyx:
{{{
a1 = new_bigint(int(E.a1()))
a2 = new_bigint(int(E.a2()))
a3 = new_bigint(int(E.a3()))
a4 = new_bigint(int(E.a4()))
a6 = new_bigint(int(E.a6()))
}}}
Here the E.a1() etc are Sage integers, and they need to be converted into
eclib bigints which are exactly NTL ZZs. This should be possible without
going via Python ints. The new_bigint function is defined near the top
of defs.pxi is a long --> ZZ conversion (just NTL's to_ZZ). If nothing
else, I think NTL can convert decimal strings to ZZs so you could try just
replacing "int" with "str" in those 5 lines?
--
Ticket URL: <http://trac.sagemath.org/ticket/16959#comment:18>
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