#1975: elliptic curve method -- one should trivially be able to implement a toy
version, but can't anymore, which sucks
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Reporter: was | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.4.2
Component: elliptic curves | Keywords:
Author: John Cremona | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Changes (by newvalueoldvalue):
* status: new => needs_review
* author: => John Cremona
Comment:
The patch makes possible what is wanted here. It does two things:
1. in creating an instance of {{{EllipticCurve_generic}}}, if the base
ring is an {{{IntegerModRing}}} it sets the point_class to be
{{{EllipticCurvePoint_finite_field}}}. The is a class with a lot of
functionality, eheras the code previous set this to the class
{{{EllipticCurvePoint}}} (the default for generic elliptic curves) which
has no functionality at all (not even an initialiser!).
2. When a {{{ZeroDivisionError}}} is raised on trying to invert a non-
invertible element of the base ring during point arithmetic, the error
message is expanded when the base ring is an {{{IntegerModRing}}} so that
it shows a factorization of the modulus.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/1975#comment:6>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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