The polymake backend for polyhedral computations

Note

This backend requires polymake. To install it, type sage -i polymake in the terminal.

AUTHORS:

  • Matthias Köppe (2017-03): initial version
class sage.geometry.polyhedron.backend_polymake.Polyhedron_QQ_polymake(parent, Vrep, Hrep, polymake_polytope=None, **kwds)

Bases: sage.geometry.polyhedron.backend_polymake.Polyhedron_polymake, sage.geometry.polyhedron.base_QQ.Polyhedron_QQ

Polyhedra over \(\QQ\) with polymake.

INPUT:

  • Vrep – a list [vertices, rays, lines] or None
  • Hrep – a list [ieqs, eqns] or None

EXAMPLES:

sage: p = Polyhedron(vertices=[(0,0),(1,0),(0,1)],                 # optional - polymake
....:                rays=[(1,1)], lines=[],
....:                backend='polymake', base_ring=QQ)
sage: TestSuite(p).run(skip='_test_pickling')                      # optional - polymake
class sage.geometry.polyhedron.backend_polymake.Polyhedron_ZZ_polymake(parent, Vrep, Hrep, polymake_polytope=None, **kwds)

Bases: sage.geometry.polyhedron.backend_polymake.Polyhedron_polymake, sage.geometry.polyhedron.base_ZZ.Polyhedron_ZZ

Polyhedra over \(\ZZ\) with polymake.

INPUT:

  • Vrep – a list [vertices, rays, lines] or None
  • Hrep – a list [ieqs, eqns] or None

EXAMPLES:

sage: p = Polyhedron(vertices=[(0,0),(1,0),(0,1)],                 # optional - polymake
....:                rays=[(1,1)], lines=[],
....:                backend='polymake', base_ring=ZZ)
sage: TestSuite(p).run(skip='_test_pickling')                      # optional - polymake
class sage.geometry.polyhedron.backend_polymake.Polyhedron_polymake(parent, Vrep, Hrep, polymake_polytope=None, **kwds)

Bases: sage.geometry.polyhedron.base.Polyhedron_base

Polyhedra with polymake

INPUT:

  • parent – Polyhedra the parent
  • Vrep – a list [vertices, rays, lines] or None; the V-representation of the polyhedron; if None, the polyhedron is determined by the H-representation
  • Hrep – a list [ieqs, eqns] or None; the H-representation of the polyhedron; if None, the polyhedron is determined by the V-representation
  • polymake_polytope – a polymake polytope object

Only one of Vrep, Hrep, or polymake_polytope can be different from None.

EXAMPLES:

sage: p = Polyhedron(vertices=[(0,0),(1,0),(0,1)], rays=[(1,1)],   # optional - polymake
....:                lines=[], backend='polymake')
sage: TestSuite(p).run(skip='_test_pickling')                      # optional - polymake

A lower-dimensional affine cone; we test that there are no mysterious inequalities coming in from the homogenization:

sage: P = Polyhedron(vertices=[(1, 1)], rays=[(0, 1)],             # optional - polymake
....:                backend='polymake')
sage: P.n_inequalities()                                           # optional - polymake
1
sage: P.equations()                                                # optional - polymake
(An equation (1, 0) x - 1 == 0,)

The empty polyhedron:

sage: Polyhedron(eqns=[[1, 0, 0]], backend='polymake')             # optional - polymake
The empty polyhedron in QQ^2

It can also be obtained differently:

sage: P=Polyhedron(ieqs=[[-2, 1, 1], [-3, -1, -1], [-4, 1, -2]],   # optional - polymake
....:              backend='polymake')
sage: P                                                            # optional - polymake
The empty polyhedron in QQ^2
sage: P.Vrepresentation()                                          # optional - polymake
()
sage: P.Hrepresentation()                                          # optional - polymake
(An equation -1 == 0,)

The full polyhedron:

sage: Polyhedron(eqns=[[0, 0, 0]], backend='polymake')             # optional - polymake
A 2-dimensional polyhedron in QQ^2 defined as the convex hull of 1 vertex and 2 lines
sage: Polyhedron(ieqs=[[0, 0, 0]], backend='polymake')             # optional - polymake
A 2-dimensional polyhedron in QQ^2 defined as the convex hull of 1 vertex and 2 lines

Quadratic fields work:

sage: V = polytopes.dodecahedron().vertices_list()
sage: Polyhedron(vertices=V, backend='polymake')                   # optional - polymake
A 3-dimensional polyhedron in (Number Field in sqrt5 with defining polynomial x^2 - 5)^3 defined as the convex hull of 20 vertices