Trac #28866: doctest killed due to abort in geometry/polyhedron/base.py

On a clean develop branch running `SageMath version 9.1.beta9, Release
Date: 2020-03-29`, I get:

{{{
$ sage -t --long --memlimit=3600 src/sage/geometry/polyhedron/base.py
too many failed tests, not using stored timings
Running doctests with ID 2020-04-01-21-12-24-30fbb892.
Git branch: develop
Using --optional=4ti2,build,cbc,ccache,cryptominisat,dochtml,dot2tex,e_a
ntic,glucose,latte_int,lidia,lrslib,memlimit,normaliz,notedown,openssl,p
andoc_attributes,pycosat,pynormaliz,rst2ipynb,sage,sage_numerical_backen
ds_coin,sage_numerical_backends_cplex,sage_numerical_backends_gurobi
Doctesting 1 file.
sage -t --long src/sage/geometry/polyhedron/base.py
    [1485 tests, 26.12 s]
----------------------------------------------------------------------
All tests passed!
----------------------------------------------------------------------
Total time for all tests: 26.4 seconds
    cpu time: 24.0 seconds
    cumulative wall time: 26.1 seconds
}}}

while

{{{
sage -t --long --memlimit=3500 src/sage/geometry/polyhedron/base.py
}}}
or
{{{
sage -t --long src/sage/geometry/polyhedron/base.py
}}}

gives

{{{
Using --optional=4ti2,build,cbc,ccache,cryptominisat,dochtml,dot2tex,e_a
ntic,glucose,latte_int,lidia,lrslib,memlimit,normaliz,notedown,openssl,p
andoc_attributes,pycosat,pynormaliz,rst2ipynb,sage,sagenb
Doctesting 1 file.
sage -t --long src/sage/geometry/polyhedron/base.py
**********************************************************************
File "src/sage/geometry/polyhedron/base.py", line 7172, in
sage.geometry.polyhedron.base.Polyhedron_base.integral_points
Failed example:
    P = 1/10*polytopes.hypercube(14)
Exception raised:
    Traceback (most recent call last):
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/doctest/forker.py", line 681, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/doctest/forker.py", line 1123, in compile_and_execute
        exec(compiled, globs)
      File "<doctest
sage.geometry.polyhedron.base.Polyhedron_base.integral_points[12]>",
line 1, in <module>
        P = Integer(1)/Integer(10)*polytopes.hypercube(Integer(14))
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/geometry/polyhedron/library.py", line 2749, in hypercube
        return Polyhedron(vertices=list(itertools.product([1, -1],
repeat=dim)), base_ring=ZZ, backend=backend)
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/geometry/polyhedron/constructor.py", line 626, in
Polyhedron
        return parent(Vrep, Hrep, convert=convert, verbose=verbose)
      File "sage/structure/parent.pyx", line 902, in
sage.structure.parent.Parent.__call__
(build/cythonized/sage/structure/parent.c:9245)
        return mor._call_with_args(x, args, kwds)
      File "sage/structure/coerce_maps.pyx", line 180, in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_with_args
(build/cythonized/sage/structure/coerce_maps.c:5081)
        raise
      File "sage/structure/coerce_maps.pyx", line 175, in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_with_args
(build/cythonized/sage/structure/coerce_maps.c:4969)
        return C._element_constructor(x, *args, **kwds)
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/geometry/polyhedron/parent.py", line 525, in
_element_constructor_
        return self.element_class(self, Vrep, Hrep, **kwds)
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/geometry/polyhedron/base.py", line 121, in __init__
        self._init_from_Vrepresentation(vertices, rays, lines, **kwds)
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/geometry/polyhedron/backend_ppl.py", line 93, in
_init_from_Vrepresentation
        self._init_Vrepresentation_from_ppl(minimize)
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-
packages/sage/geometry/polyhedron/backend_ppl.py", line 161, in
_init_Vrepresentation_from_ppl
        gs = self._ppl_polyhedron.minimized_generators()
      File "ppl/polyhedron.pyx", line 335, in
ppl.polyhedron.Polyhedron.minimized_generators
    RuntimeError: Aborted
**********************************************************************

...

    Killed due to abort
**********************************************************************
Tests run before process (pid=19555) failed:
sage: p = polytopes.hypercube(2) ## line 71 ##
sage: from sage.geometry.polyhedron.base import is_Polyhedron ## line 72
##
sage: is_Polyhedron(p) ## line 73 ##
True

...

sage: v = [(1,0,7,-1), (-2,-2,4,-3), (-1,-1,-1,4), (2,9,0,-5),
(-2,-1,5,1)] ## line 7164 ##
sage: simplex = Polyhedron(v); simplex ## line 7165 ##
A 4-dimensional polyhedron in ZZ^4 defined as the convex hull of 5
vertices
sage: len(simplex.integral_points()) ## line 7167 ##
49
sage: P = 1/10*polytopes.hypercube(14) ## line 7172 ##
sig_error() without sig_on()

----------------------------------------------------------------------
sage -t --long src/sage/geometry/polyhedron/base.py  # Killed due to
abort
----------------------------------------------------------------------
}}}

URL: https://trac.sagemath.org/28866
Reported by: slabbe
Ticket author(s): Jonathan Kliem
Reviewer(s): Sébastien Labbé, Michael Orlitzky, Matthias Koeppe

Author: Release Manager

src/sage/geometry/polyhedron/base.py

@@ -104,6 +104,10 @@ class Polyhedron_base(Element):
 
     - ``Hrep_minimal`` (optional) -- see below
 
+    - ``pref_rep`` -- string (default: ``None``);
+       one of``Vrep`` or ``Hrep`` to pick this in case the backend
+       cannot initialize from complete double description
+
     If both ``Vrep`` and ``Hrep`` are provided, then
     ``Vrep_minimal`` and ``Hrep_minimal`` must be set to ``True``.
 
@@ -113,7 +117,7 @@ class Polyhedron_base(Element):
         sage: TestSuite(p).run()
     """
 
-    def __init__(self, parent, Vrep, Hrep, Vrep_minimal=None, Hrep_minimal=None, **kwds):
+    def __init__(self, parent, Vrep, Hrep, Vrep_minimal=None, Hrep_minimal=None, pref_rep=None, **kwds):
         """
         Initializes the polyhedron.
 
@@ -134,6 +138,35 @@ def __init__(self, parent, Vrep, Hrep, Vrep_minimal=None, Hrep_minimal=None, **k
             Traceback (most recent call last):
             ...
             ValueError: if both Vrep and Hrep are provided, they must be minimal...
+
+        Illustration of ``pref_rep``.
+        Note that ``ppl`` doesn't support precomputed data::
+
+            sage: from sage.geometry.polyhedron.backend_ppl import Polyhedron_QQ_ppl
+            sage: from sage.geometry.polyhedron.parent import Polyhedra_QQ_ppl
+            sage: parent = Polyhedra_QQ_ppl(QQ, 1, 'ppl')
+            sage: p = Polyhedron_QQ_ppl(parent, Vrep, 'nonsense',
+            ....:                       Vrep_minimal=True, Hrep_minimal=True, pref_rep='Vrep')
+            sage: p = Polyhedron_QQ_ppl(parent, 'nonsense', Hrep,
+            ....:                       Vrep_minimal=True, Hrep_minimal=True, pref_rep='Hrep')
+            sage: p = Polyhedron_QQ_ppl(parent, 'nonsense', Hrep,
+            ....:                       Vrep_minimal=True, Hrep_minimal=True, pref_rep='Vrepresentation')
+            Traceback (most recent call last):
+            ...
+            ValueError: ``pref_rep`` must be one of ``(None, 'Vrep', 'Hrep')``
+
+        If the backend supports precomputed data, ``pref_rep`` is ignored::
+
+            sage: p = Polyhedron_field(parent, Vrep, 'nonsense',  # py3
+            ....:                      Vrep_minimal=True, Hrep_minimal=True, pref_rep='Vrep')
+            Traceback (most recent call last):
+            ...
+            TypeError: _init_Hrepresentation() takes 3 positional arguments but 9 were given
+            sage: p = Polyhedron_field(parent, Vrep, 'nonsense',  # py2
+            ....:                      Vrep_minimal=True, Hrep_minimal=True, pref_rep='Vrep')
+            Traceback (most recent call last):
+            ...
+            TypeError: _init_Hrepresentation() takes exactly 3 arguments (9 given)
         """
         Element.__init__(self, parent=parent)
         if Vrep is not None and Hrep is not None:
@@ -144,11 +177,20 @@ def __init__(self, parent, Vrep, Hrep, Vrep_minimal=None, Hrep_minimal=None, **k
                 self._init_from_Vrepresentation_and_Hrepresentation(Vrep, Hrep)
                 return
             else:
-                # Initialize from Hrepresentation if this seems simpler.
-                Vrep = [tuple(Vrep[0]), tuple(Vrep[1]), Vrep[2]]
-                Hrep = [tuple(Hrep[0]), Hrep[1]]
-                if len(Hrep[0]) < len(Vrep[0]) + len(Vrep[1]):
+                if pref_rep is None:
+                    # Initialize from Hrepresentation if this seems simpler.
+                    Vrep = [tuple(Vrep[0]), tuple(Vrep[1]), Vrep[2]]
+                    Hrep = [tuple(Hrep[0]), Hrep[1]]
+                    if len(Hrep[0]) < len(Vrep[0]) + len(Vrep[1]):
+                        pref_rep = 'Hrep'
+                    else:
+                        pref_rep = 'Vrep'
+                if pref_rep == 'Vrep':
+                    Hrep = None
+                elif pref_rep == 'Hrep':
                     Vrep = None
+                else:
+                    raise ValueError("``pref_rep`` must be one of ``(None, 'Vrep', 'Hrep')``")
         if Vrep is not None:
             vertices, rays, lines = Vrep
             if vertices or rays or lines:
@@ -1080,11 +1122,12 @@ def cdd_Hrepresentation(self):
             H-representation
             begin
              4 3 rational
-             1 1 0
-             1 0 1
              1 -1 0
              1 0 -1
+             1 1 0
+             1 0 1
             end
+            <BLANKLINE>
 
             sage: triangle = Polyhedron(vertices = [[1,0],[0,1],[1,1]],base_ring=AA)
             sage: triangle.base_ring()
@@ -4461,36 +4504,30 @@ def dilation(self, scalar):
             sage: test_dilation(polytopes.permutahedron(3)*Polyhedron(rays=[[0,0,1],[0,1,1]], lines=[[1,0,0]]))
         """
         parent = self.parent().base_extend(scalar)
-        one = parent.base_ring().one()
-        if scalar > 0:
-            new_vertices = [ list(scalar*v.vector()) for v in self.vertex_generator() ]
-            new_rays = self.rays()
-            new_lines = self.lines()
-            new_inequalities = [f.vector()*one for f in self.inequality_generator()]
-            for f in new_inequalities:
-                f[0] *= scalar
-            new_equations = [e.vector()*one for e in self.equation_generator()]
-            for e in new_equations:
-                e[0] *= scalar
-        elif scalar < 0:
-            new_vertices = [ list(scalar*v.vector()) for v in self.vertex_generator() ]
-            new_rays = [ list(-r.vector()) for r in self.ray_generator()]
-            new_lines = self.lines()
-            new_inequalities = [-f.vector()*one for f in self.inequality_generator()]
-            for f in new_inequalities:
-                f[0] *= scalar
-            new_equations = [-e.vector()*one for e in self.equation_generator()]
-            for e in new_equations:
-                e[0] *= scalar
-        else:
-            new_vertices = [ self.ambient_space().zero() for v in self.vertex_generator() ]
+
+        if scalar == 0:
+            new_vertices = tuple(self.ambient_space().zero() for v in self.vertex_generator())
             new_rays = []
             new_lines = []
             return parent.element_class(parent, [new_vertices, new_rays, new_lines], None)
 
+        one = parent.base_ring().one()
+        sign = one if scalar > 0 else -one
+
+        make_new_Hrep = lambda h : tuple(scalar*sign*x if i == 0 else sign*x
+                                         for i,x in enumerate(h._vector))
+
+        new_vertices = (tuple(scalar*x for x in v._vector) for v in self.vertex_generator())
+        new_rays = (tuple(sign*x for x in r._vector) for r in self.ray_generator())
+        new_lines = self.line_generator()
+        new_inequalities = map(make_new_Hrep, self.inequality_generator())
+        new_equations = map(make_new_Hrep, self.equation_generator())
+
+        pref_rep = 'Vrep' if self.n_vertices() + self.n_rays() <= self.n_inequalities() else 'Hrep'
+
         return parent.element_class(parent, [new_vertices, new_rays, new_lines],
                                     [new_inequalities, new_equations],
-                                    Vrep_minimal=True, Hrep_minimal=True)
+                                    Vrep_minimal=True, Hrep_minimal=True, pref_rep=pref_rep)
 
     def linear_transformation(self, linear_transf):
         """
@@ -5622,20 +5659,20 @@ def face_lattice(self):
             sage: fl = square.face_lattice();fl
             Finite lattice containing 10 elements with distinguished linear extension
             sage: list(f.ambient_V_indices() for f in fl)
-            [(), (0,), (1,), (2,), (3,), (0, 1), (0, 2), (2, 3), (1, 3), (0, 1, 2, 3)]
+            [(), (0,), (1,), (2,), (3,), (0, 1), (1, 2), (2, 3), (0, 3), (0, 1, 2, 3)]
             sage: poset_element = fl[6]
             sage: a_face = poset_element
             sage: a_face
             A 1-dimensional face of a Polyhedron in ZZ^2 defined as the convex hull of 2 vertices
             sage: a_face.ambient_V_indices()
-            (0, 2)
+            (1, 2)
             sage: set(a_face.ambient_Vrepresentation()) == \
-            ....: set([square.Vrepresentation(0), square.Vrepresentation(2)])
+            ....: set([square.Vrepresentation(1), square.Vrepresentation(2)])
             True
             sage: a_face.ambient_Vrepresentation()
-            (A vertex at (-1, -1), A vertex at (1, -1))
+            (A vertex at (1, 1), A vertex at (-1, 1))
             sage: a_face.ambient_Hrepresentation()
-            (An inequality (0, 1) x + 1 >= 0,)
+            (An inequality (0, -1) x + 1 >= 0,)
 
         A more complicated example::
 
@@ -7958,8 +7995,8 @@ def integral_points(self, threshold=100000):
 
         A case where rounding in the right direction goes a long way::
 
-            sage: P = 1/10*polytopes.hypercube(14)  # long time
-            sage: P.integral_points()  # long time
+            sage: P = 1/10*polytopes.hypercube(14, backend='field')
+            sage: P.integral_points()
             ((0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),)
 
         Finally, the 3-d reflexive polytope number 4078::

src/sage/geometry/polyhedron/face.py

@@ -341,9 +341,9 @@ def __richcmp__(self, other, op):
             sage: square = polytopes.hypercube(2)
             sage: f = square.faces(1)
             sage: matrix(4,4, lambda i,j: ZZ(f[i] <= f[j]))
-            [1 1 0 0]
-            [0 1 0 0]
             [1 1 1 0]
+            [0 1 0 0]
+            [0 1 1 0]
             [1 1 1 1]
             sage: matrix(4,4, lambda i,j: ZZ(f[i] == f[j])) == 1
             True
@@ -379,16 +379,16 @@ def ambient_Hrepresentation(self, index=None):
             sage: square = polytopes.hypercube(2)
             sage: for face in square.face_lattice():
             ....:     print(face.ambient_Hrepresentation())
-            (An inequality (1, 0) x + 1 >= 0, An inequality (0, 1) x + 1 >= 0,
-             An inequality (-1, 0) x + 1 >= 0, An inequality (0, -1) x + 1 >= 0)
-            (An inequality (1, 0) x + 1 >= 0, An inequality (0, 1) x + 1 >= 0)
-            (An inequality (1, 0) x + 1 >= 0, An inequality (0, -1) x + 1 >= 0)
-            (An inequality (0, 1) x + 1 >= 0, An inequality (-1, 0) x + 1 >= 0)
+            (An inequality (-1, 0) x + 1 >= 0, An inequality (0, -1) x + 1 >= 0,
+             An inequality (1, 0) x + 1 >= 0, An inequality (0, 1) x + 1 >= 0)
+            (An inequality (-1, 0) x + 1 >= 0, An inequality (0, 1) x + 1 >= 0)
             (An inequality (-1, 0) x + 1 >= 0, An inequality (0, -1) x + 1 >= 0)
-            (An inequality (1, 0) x + 1 >= 0,)
-            (An inequality (0, 1) x + 1 >= 0,)
+            (An inequality (0, -1) x + 1 >= 0, An inequality (1, 0) x + 1 >= 0)
+            (An inequality (1, 0) x + 1 >= 0, An inequality (0, 1) x + 1 >= 0)
             (An inequality (-1, 0) x + 1 >= 0,)
             (An inequality (0, -1) x + 1 >= 0,)
+            (An inequality (1, 0) x + 1 >= 0,)
+            (An inequality (0, 1) x + 1 >= 0,)
             ()
         """
         if index is None:
@@ -421,16 +421,16 @@ def ambient_Vrepresentation(self, index=None):
             sage: for fl in square.face_lattice():
             ....:     print(fl.ambient_Vrepresentation())
             ()
-            (A vertex at (-1, -1),)
-            (A vertex at (-1, 1),)
             (A vertex at (1, -1),)
             (A vertex at (1, 1),)
-            (A vertex at (-1, -1), A vertex at (-1, 1))
-            (A vertex at (-1, -1), A vertex at (1, -1))
+            (A vertex at (-1, 1),)
+            (A vertex at (-1, -1),)
             (A vertex at (1, -1), A vertex at (1, 1))
-            (A vertex at (-1, 1), A vertex at (1, 1))
-            (A vertex at (-1, -1), A vertex at (-1, 1),
-             A vertex at (1, -1), A vertex at (1, 1))
+            (A vertex at (1, 1), A vertex at (-1, 1))
+            (A vertex at (-1, 1), A vertex at (-1, -1))
+            (A vertex at (1, -1), A vertex at (-1, -1))
+            (A vertex at (1, -1), A vertex at (1, 1),
+             A vertex at (-1, 1), A vertex at (-1, -1))
         """
         if index is None:
             return self._ambient_Vrepresentation

src/sage/geometry/polyhedron/library.py

@@ -2831,26 +2831,25 @@ def hypercube(self, dim, intervals=None, backend=None):
         parent = Polyhedra(ZZ, dim, backend=backend)
         convert = False
 
-        # Preparing the inequalities:
         # If the intervals are (a_1,b_1), ..., (a_dim, b_dim),
         # then the inequalites correspond to
         # b_1,b_2,...,b_dim, a_1,a_2,...,a_dim
         # in that order.
-        ieqs = [[0]*(dim+1) for _ in range(2*dim)]
-        for i in range(dim):
-            ieqs[i][i+1] = -1
-            ieqs[dim+i][i+1] = 1
 
         if intervals is None:
-            cp = list(itertools.product([-1,1], repeat=dim))
-            for i in range(dim):
-                ieqs[i][0]     = 1  # An inequality -x_i + 1 >= 0
-                ieqs[i+dim][0] = 1  # An inequality  x_i + 1 >= 0
+            cp = itertools.product((-1,1), repeat=dim)
+
+            # An inequality -x_i       + 1 >= 0 for i <  dim
+            # resp.          x_{dim-i} + 1 >= 0 for i >= dim
+            ieq_b = lambda i: 1
+
         elif isinstance(intervals, str):
             if intervals == 'zero_one':
-                cp = list(itertools.product([0,1], repeat=dim))
-                for i in range(dim):
-                    ieqs[i][0] = 1  # An inequality -x_i + 1 >= 0
+                cp = itertools.product((0,1), repeat=dim)
+
+                # An inequality -x_i       + 1 >= 0 for i <  dim
+                # resp.          x_{dim-i} + 0 >= 0 for i >= dim
+                ieq_b = lambda i: 1 if i < dim else 0
             else:
                 raise ValueError("the only allowed string is 'zero_one'")
         elif len(intervals) == dim:
@@ -2864,14 +2863,25 @@ def hypercube(self, dim, intervals=None, backend=None):
                 # the specified backend cannot handle the intervals.
                 raise ValueError("specified backend {} cannot handle the intervals".format(backend))
 
-            cp = list(itertools.product(*intervals))
-            for i in range(dim):
-                ieqs[i][0]     =  intervals[i][1]  # An inequality -x_i + b_i >= 0
-                ieqs[i+dim][0] = -intervals[i][0]  # An inequality  x_i - a_i >= 0
+            cp = itertools.product(*intervals)
 
+            # An inequality -x_i       + b_i >= 0 for i <  dim
+            # resp.          x_{dim-i} - a_i >= 0 for i >= dim
+            ieq_b = lambda i: intervals[i][1] if i < dim \
+                              else intervals[i-dim][0]
         else:
             raise ValueError("the dimension of the hypercube must match the number of intervals")
-        return parent([cp, [], []], [ieqs, []], convert=convert, Vrep_minimal=True, Hrep_minimal=True)
+
+        # An inequality -x_i       + ieq_b(i)     >= 0 for i <  dim
+        # resp.          x_{dim-i} + ieq_b(i-dim) >= 0 for i >= dim
+        ieq_A = lambda i, pos: -1 if i == pos           \
+                               else 1 if i == pos + dim \
+                               else 0
+        ieqs = (tuple(ieq_b(i) if pos == 0 else ieq_A(i, pos-1)
+                      for pos in range(dim+1))
+                for i in range(2*dim))
+
+        return parent([cp, [], []], [ieqs, []], convert=convert, Vrep_minimal=True, Hrep_minimal=True, pref_rep='Hrep')
 
     def cube(self, intervals=None, backend=None):
         r"""
@@ -2970,9 +2980,9 @@ def cross_polytope(self, dim, backend=None):
         """
         verts = tuple((ZZ**dim).basis())
         verts += tuple(-v for v in verts)
-        ieqs = tuple((1,) + x for x in itertools.product([-1,1], repeat=dim))
+        ieqs = ((1,) + x for x in itertools.product((-1,1), repeat=dim))
         parent = Polyhedra(ZZ, dim, backend=backend)
-        return parent([verts, [], []], [ieqs, []], Vrep_minimal=True, Hrep_minimal=True)
+        return parent([verts, [], []], [ieqs, []], Vrep_minimal=True, Hrep_minimal=True, pref_rep='Vrep')
 
     def parallelotope(self, generators, backend=None):
         r"""

src/sage/geometry/triangulation/element.py

@@ -606,10 +606,10 @@ def _boundary_simplex_dictionary(self):
             sage: triangulation = polytopes.hypercube(2).triangulate(engine='internal')
             sage: triangulation._boundary_simplex_dictionary()
             {(0, 1): ((0, 1, 3),),
-             (0, 2): ((0, 2, 3),),
-             (0, 3): ((0, 1, 3), (0, 2, 3)),
-             (1, 3): ((0, 1, 3),),
-             (2, 3): ((0, 2, 3),)}
+             (0, 3): ((0, 1, 3),),
+             (1, 2): ((1, 2, 3),),
+             (1, 3): ((0, 1, 3), (1, 2, 3)),
+             (2, 3): ((1, 2, 3),)}
 
             sage: triangulation = polytopes.cube().triangulate(engine='internal')
             sage: triangulation._boundary_simplex_dictionary()
@@ -739,21 +739,21 @@ def normal_cone(self):
 
             sage: triangulation = polytopes.hypercube(2).triangulate(engine='internal')
             sage: triangulation
-            (<0,1,3>, <0,2,3>)
+            (<0,1,3>, <1,2,3>)
             sage: N = triangulation.normal_cone();  N
             4-d cone in 4-d lattice
             sage: N.rays()
-            (-1,  0,  0,  0),
-            ( 1,  0,  1,  0),
-            (-1,  0, -1,  0),
-            ( 1,  0,  0, -1),
-            (-1,  0,  0,  1),
-            ( 1,  1,  0,  0),
-            (-1, -1,  0,  0)
+            ( 0,  0,  0, -1),
+            ( 0,  0,  1,  1),
+            ( 0,  0, -1, -1),
+            ( 1,  0,  0,  1),
+            (-1,  0,  0, -1),
+            ( 0,  1,  0, -1),
+            ( 0, -1,  0,  1)
             in Ambient free module of rank 4
             over the principal ideal domain Integer Ring
             sage: N.dual().rays()
-            (-1, 1, 1, -1)
+            (1, -1, 1, -1)
             in Ambient free module of rank 4
             over the principal ideal domain Integer Ring
 

src/sage/plot/graphics.py

@@ -3403,12 +3403,12 @@ def description(self):
         EXAMPLES::
 
             sage: print(polytopes.hypercube(2).plot().description())
-            Polygon defined by 4 points: [(1.0, 1.0), (-1.0, 1.0), (-1.0, -1.0), (1.0, -1.0)]
-            Line defined by 2 points: [(-1.0, -1.0), (-1.0, 1.0)]
-            Line defined by 2 points: [(-1.0, -1.0), (1.0, -1.0)]
-            Line defined by 2 points: [(-1.0, 1.0), (1.0, 1.0)]
+            Polygon defined by 4 points: [(-1.0, -1.0), (1.0, -1.0), (1.0, 1.0), (-1.0, 1.0)]
+            Line defined by 2 points: [(-1.0, 1.0), (-1.0, -1.0)]
+            Line defined by 2 points: [(1.0, -1.0), (-1.0, -1.0)]
             Line defined by 2 points: [(1.0, -1.0), (1.0, 1.0)]
-            Point set defined by 4 point(s): [(-1.0, -1.0), (-1.0, 1.0), (1.0, -1.0), (1.0, 1.0)]
+            Line defined by 2 points: [(1.0, 1.0), (-1.0, 1.0)]
+            Point set defined by 4 point(s): [(1.0, -1.0), (1.0, 1.0), (-1.0, 1.0), (-1.0, -1.0)]
         """
         data = []
         for g in self: