#16625: Schlegel doesn't work for all polytopes
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Reporter: kcrisman | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.3
Component: geometry | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Description changed by kcrisman:
Old description:
> In comments for [http://ask.sagemath.org/question/23223
> /projection_direction-broken-for-polytopes/ this ask.sagemath question],
> we see that
> {{{
> sage: P8 = polytopes.n_cube(4)
> sage: P8.schlegel([2,5,11,17])
> AttributeError: 'Polyhedra_ZZ_ppl_with_category.element_class' object has
> no attribute 'schlegel'
> }}}
> while for polytopes defined over `QQ` this isn't a problem. The
> documentation for polytope plotting doesn't seem to indicate this, other
> than a mysterious and ill-placed
> [http://www.sagemath.org/doc/reference/geometry/sage/geometry/polyhedron/plot.html#sage.geometry.polyhedron.plot.Projection.tikz
> todo in the tikz method], which might not even be related.
>
> ----
>
> On a related note, from the same question, the two following should be
> different, but aren't. This is a different bug; apparently it used to
> work.
> {{{
> poly = polytopes.twenty_four_cell()
> poly.show()
>
> poly.show(projection_direction=[2,5,11,17])
> }}}
New description:
In comments for [http://ask.sagemath.org/question/23223
/projection_direction-broken-for-polytopes/ this ask.sagemath question],
we see that
{{{
sage: P8 = polytopes.n_cube(4)
sage: P8.schlegel([2,5,11,17])
AttributeError: 'Polyhedra_ZZ_ppl_with_category.element_class' object has
no attribute 'schlegel'
}}}
while for polytopes defined over `QQ` this isn't a problem. The
documentation for polytope plotting doesn't seem to indicate this, other
than a mysterious and ill-placed
[http://www.sagemath.org/doc/reference/geometry/sage/geometry/polyhedron/plot.html#sage.geometry.polyhedron.plot.Projection.tikz
todo in the tikz method], which might not even be related.
----
Two related things which may or may not be bugs.
From the same question, the two following should be different, but aren't.
This is a different bug; apparently it used to work.
{{{
poly = polytopes.twenty_four_cell()
poly.show()
poly.show(projection_direction=[2,5,11,17])
}}}
Also,
{{{
sage: P8.base_ring?
Type: instancemethod
String form: <bound method
Polyhedra_ZZ_ppl_with_category.element_class.base_ring of A 4-dimensional
polyhedron in ZZ^4 defined as the convex hull of 16 vertices>
Definition: P8.base_ring(self)
Docstring:
Return the base ring.
OUTPUT:
Either "QQ" (exact arithmetic using gmp, default) or "RDF" (double
precision floating-point arithmetic)
EXAMPLES:
sage: triangle = Polyhedron(vertices = [[1,0],[0,1],[1,1]])
sage: triangle.base_ring() == ZZ
True
}}}
I particularly like how the **example** directly contradicts the
documentation ;-)
--
--
Ticket URL: <http://trac.sagemath.org/ticket/16625#comment:1>
Sage <http://www.sagemath.org>
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