#16625: projection_direction broken for polytopes
----------------------------+------------------------
       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.
>
> ----
>
> 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 ;-)

New description:

 From [http://ask.sagemath.org/question/23223/projection_direction-broken-
 for-polytopes/ this ask.sagemath question], the two following should be
 different, but aren't.
 {{{
 poly = polytopes.twenty_four_cell()
 poly.show()

 poly.show(projection_direction=[2,5,11,17])
 }}}

--

--
Ticket URL: <http://trac.sagemath.org/ticket/16625#comment:3>
Sage <http://www.sagemath.org>
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