#9880: Segfault in PyNaC 0.2.0.p4
-------------------------+--------------------------------------------------
Reporter: jpflori | Owner: burcin
Type: defect | Status: needs_review
Priority: major | Milestone: sage-4.6.2
Component: symbolics | Keywords: pynac
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
-------------------------+--------------------------------------------------
Comment(by jpflori):
Replying to [comment:24 vbraun]:
> Burcin: If you are working on pynac, can you add some private
function/method that exposes the GiNaC order to Sage in addition to the
Sage (printing) order? Then we can add some randomized testing to make
sure that both are strict weak orders.
Calling the _cmp_ method of an expression should give you access to pynac
internal ordering (i.e. with the patched spkg, it is GiNaC original
ordering; with the old one you would get the modified order currently used
by pynac).
For example (with the new spkg):
{{{
sage: var('a b')
(a, b)
sage: x._cmp_(a)
1
sage: a._cmp_(b)
1
sage: a+b
a + b
sage: x+a
a + x
}}}
In GiNaC order, vars are ordered according to creation order iirc. So here
we have x (automatically created) > a > b.
For printing, we use lexicographic order a > b > x and print bigger terms
first.
To check it the only current way is to look at what gets printed, the
internal ordering is used for everything else.
I'll try to post a minimal patch to have access to that order in sage.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9880#comment:25>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
