#13638: fix adjacency of rays
--------------------------------+-------------------------------------------
Reporter: vbraun | Owner: mhampton
Type: defect | Status: needs_review
Priority: major | Milestone: sage-5.5
Component: geometry | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Volker Braun | Merged in:
Dependencies: | Stopgaps:
--------------------------------+-------------------------------------------
Changes (by vbraun):
* status: new => needs_review
Old description:
> The adjacency of rays in polyhedra isn't right. This impacts some corner
> cases in plotting 2-d non-compact polytopes.
New description:
The adjacency of rays in polyhedra isn't right. This impacts some corner
cases in plotting 2-d non-compact polytopes:
{{{
sage: P = Polyhedron(vertices=[(0, 1), (1, 0), (2, 0), (3, 0), (4, 1)],
rays=[(0,1)]).plot()
---------------------------------------------------------------------------
ValueError Traceback (most recent call
last)
/home/vbraun/opt/sage-5.4.rc1/devel/sage-main/<ipython console> in
<module>()
/home/vbraun/opt/sage-5.4.rc1/local/lib/python2.7/site-
packages/sage/geometry/polyhedron/base.pyc in plot(self, **kwds)
516 render = render_method[self.ambient_dim()]
517 if render != None:
--> 518 return render(self,**kwds)
519 raise NotImplementedError('Plotting of
'+str(self.ambient_dim())+
520 '-dimensional polyhedra not
implemented')
/home/vbraun/opt/sage-5.4.rc1/local/lib/python2.7/site-
packages/sage/geometry/polyhedron/plot.pyc in render_2d(projection,
**kwds)
54 """
55 if is_Polyhedron(projection):
---> 56 projection = Projection(projection)
57 return \
58 projection.render_points_2d(zorder=2, pointsize=10,
**kwds) + \
/home/vbraun/opt/sage-5.4.rc1/local/lib/python2.7/site-
packages/sage/geometry/polyhedron/plot.pyc in __init__(self, polyhedron,
proj)
411
412 if polyhedron.ambient_dim() == 2:
--> 413 self._init_from_2d(polyhedron)
414 elif polyhedron.ambient_dim() == 3:
415 self._init_from_3d(polyhedron)
/home/vbraun/opt/sage-5.4.rc1/local/lib/python2.7/site-
packages/sage/geometry/polyhedron/plot.pyc in _init_from_2d(self,
polyhedron)
630 self._init_points(polyhedron)
631 self._init_lines_arrows(polyhedron)
--> 632 self._init_area_2d(polyhedron)
633
634
/home/vbraun/opt/sage-5.4.rc1/local/lib/python2.7/site-
packages/sage/geometry/polyhedron/plot.pyc in _init_area_2d(self,
polyhedron)
727 assert polyhedron.ambient_dim() == 2, "Requires polyhedron
in 2d"
728 vertices = [v for v in polyhedron.Vrep_generator()]
--> 729 vertices = cyclic_sort_vertices_2d(vertices)
730 coords = []
731
/home/vbraun/opt/sage-5.4.rc1/local/lib/python2.7/site-
packages/sage/geometry/polyhedron/plot.pyc in
cyclic_sort_vertices_2d(Vlist)
188 break;
189 else:
--> 190 raise ValueError
191 return result
192
ValueError:
}}}
Attach [attachment:trac_13638_ray_adjacency_fix.patch]
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13638#comment:1>
Sage <http://www.sagemath.org>
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