Bug in product of polyhedra

[Victor Miller]

The cartesian product of two polyhedra doesn't work if their dimensions are different:

Consider the following (just run on sagenb.org):

sage: B1 = Polyhedron(vertice=[(0,),(1,)])
sage: B1

A 1-dimensional polyhedron in ZZ^1 defined as the convex hull of 2
vertices

sage: B2 = B1*B1
sage: B1

A 2-dimensional polyhedron in ZZ^2 defined as the convex hull of 4
vertices

sage: B3 = B2*B1

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "_sage_input_6.py", line 10, in <module>
    exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8 -*-\\n" + _support_.preparse_worksheet_cell(base64.b64decode("QjMgPSBCMipCMQ=="),globals())+"\\n"); execfile(os.path.abspath("___code___.py"))
  File "", line 1, in <module>
   
  File "/tmp/tmpf3Clrp/___code___.py", line 2, in <module>
    exec compile(u'B3 = B2*B1
  File "", line 1, in <module>
   
  File "/sagenb/sage_install/sage-5.11-boxen-x86_64-Linux/local/lib/python2.7/site-packages/sage/categories/magmas.py", line 313, in __mul__
    return get_coercion_model().bin_op(self, right, operator.mul)
  File "coerce.pyx", line 710, in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:8280)
  File "coerce.pyx", line 797, in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:7263)
  File "coerce.pyx", line 1272, in sage.structure.coerce.CoercionModel_cache_maps.get_action (sage/structure/coerce.c:12184)
  File "coerce.pyx", line 1389, in sage.structure.coerce.CoercionModel_cache_maps.discover_action (sage/structure/coerce.c:13239)
  File "parent.pyx", line 2417, in sage.structure.parent.Parent.get_action (sage/structure/parent.c:16728)
  File "parent.pyx", line 2493, in sage.structure.parent.Parent.discover_action (sage/structure/parent.c:17728)
  File "coerce_actions.pyx", line 217, in sage.structure.coerce_actions.detect_element_action (sage/structure/coerce_actions.c:5512)
  File "element.pyx", line 716, in sage.structure.element.Element._acted_upon_ (sage/structure/element.c:6579)
  File "/sagenb/sage_install/sage-5.11-boxen-x86_64-Linux/local/lib/python2.7/site-packages/sage/geometry/polyhedron/base.py", line 2620, in _acted_upon_
    return self.product(actor)
  File "element.pyx", line 3231, in sage.structure.element.NamedBinopMethod.__call__ (sage/structure/element.c:24955)
  File "coerce.pyx", line 998, in sage.structure.coerce.CoercionModel_cache_maps.canonical_coercion (sage/structure/coerce.c:9730)
TypeError: no common canonical parent for objects with parents: 'Polyhedra in ZZ^2' and 'Polyhedra in ZZ^1'

[Volker Braun]

Thanks, this is now http://trac.sagemath.org/ticket/15253