#12452: make it possible to inherit from sage.symbolic.expression.Expression.
------------------------------------------------------------+---------------
Reporter: burcin | Owner:
burcin
Type: enhancement | Status:
needs_work
Priority: minor | Milestone:
sage-5.0
Component: symbolics | Keywords:
Cernay2012
Work_issues: devise potential use cases, speed regression | Upstream:
N/A
Reviewer: Jean-Pierre Flori, Florent Hivert | Author:
Burcin Erocal
Merged: | Dependencies:
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Changes (by jpflori):
* cc: jpflori (added)
* status: needs_review => needs_work
* work_issues: => devise potential use cases, speed regression
Comment:
Replying to [comment:5 burcin]:
> No, this will not solve your problem. It only allows one to carry around
some information with symbolic expressions. Even then, to handle the
propagation of that info, you'd have to implement many methods yourself.
I'm not convinced if there is a real use case for this actually. There
were many requests on sage-support, but AFAICT, all those actually needed
indexed expressions not their own expression class.
I thought about what Florent told me in the RER before I fell asleep, and
it indeed looks completely non-trivial to build an actual useful extension
of the Expression class.
In particular dealing with commutativity of the addition or things like
that, in order not to restrict to additionning elements in the new
subclass.
> > - is there any measurable slowdown because of the extra work ?
> Yes, definitely: http://groups.google.com/group/sage-
support/msg/511d84f6d744621e That was based on an earlier version of this
patch.
That's quite bad.
I'll have a look at the latest patch.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12452#comment:6>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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