#13883: Fix an assertion in polybori
-------------------------------------------------------+--------------------
Reporter: SimonKing | Owner: malb
Type: defect | Status: new
Priority: major | Milestone:
sage-5.6
Component: commutative algebra | Resolution:
Keywords: polybori FGLMStrategy debug | Work issues:
Report Upstream: Reported upstream. No feedback yet. | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
-------------------------------------------------------+--------------------
Comment (by SimonKing):
We want that old_ring is in degneglex ordering. Shouldn't the following
work
{{{
sage: from polybori import *
sage: target_ring = BooleanPolynomialRing(names=['x','y','z'])
sage: source_ring.<x,y,z> = BooleanPolynomialRing(order="DegNegLex")
sage: ideal = BooleanPolynomialVector([x+z, y+z])
sage: z > y > x
True
sage: FGLMStrategy(source_ring, target_ring, ideal)
}}}
However, it still crashes!
Replying to [comment:6 jpflori]:
> But the following which looks a little better seems to work:
> {{{
> sage: sage: from polybori import *
> sage: sage: B.<x,y,z> = BooleanPolynomialRing(order='lex')
> sage: C = B.clone(ordering=dp_asc)
> sage: sage: ideal = BooleanPolynomialVector([x+z, y+z])
> sage: sage: sage: FGLMStrategy(B, C, ideal)
> <sage.rings.polynomial.pbori.FGLMStrategy object at 0x7379ab0>
> }}}
I can confirm that this works. However, big surprise:
''The following very similar attempt still crashes'':
{{{
sage: from polybori import *
sage: target_ring = BooleanPolynomialRing(3,names=['x','y','z'])
sage: source_ring = target_ring.clone(ordering=dp_asc)
sage: x,y,z = source_ring.gens()
sage: z > y > x
True
sage: ideal = BooleanPolynomialVector([x+z, y+z])
sage: FGLMStrategy(source_ring, target_ring, ideal)
python: groebner/include/polybori/groebner/PolyEntryVector.h:74: virtual
void polybori::groebner::PolyEntryVector::append(const
polybori::groebner::PolyEntry&): Assertion `m_indices.checked(back().lead)
== (size_type)-1' failed.
}}}
So, Alexander, it seems that a misuse of `._change_ordering` is ''not''
the problem. There is a bug, that ought to be fixed.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13883#comment:7>
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.
