represent the rays of wall by a matrix. add doctest

Author: yuan-zhou

src/sage/geometry/cone.py

@@ -1007,6 +1007,12 @@ def plot(self, **options):
             sage: quadrant = Cone([(1,0), (0,1)])
             sage: quadrant.plot()
             Graphics object consisting of 9 graphics primitives
+
+        Let's plot a halfplane. See :trac:`25114`.
+
+            sage: halfplane = Cone([(1,0), (0,1), (-1,0)])
+            sage: halfplane.plot()
+            Graphics object consisting of 12 graphics primitives
         """
         tp = ToricPlotter(options, self.lattice().degree(), self.rays())
         return tp.plot_lattice() + tp.plot_rays() + tp.plot_generators()

src/sage/geometry/toric_plotter.py

@@ -651,7 +651,7 @@ def plot_walls(self, walls):
             if lsd == 0:    # Strictly convex wall
                 r1, r2 = (rays[i] for i in wall.ambient_ray_indices())
             elif lsd == 1:  # wall is a half-plane
-                for i, ray in zip(wall.ambient_ray_indices(), wall.rays()):
+                for i, ray in zip(wall.ambient_ray_indices(), wall.rays().matrix()):
                     if ray in S:
                         r1 = rays[i]
                     else: