Ticket #11763: trac_11763_ZZ_polyhedron-rebase.patch

File trac_11763_ZZ_polyhedron-rebase.patch, 14.1 KB (added by davidloeffler, 8 years ago)

Rebased for new patch at 11634

  • doc/en/reference/geometry.rst 

    # HG changeset patch
# User Volker Braun <vbraun@stp.dias.ie>
# Date 1315501129 14400
# Node ID 01ee8583d6d33ad70ced4ac52f0c5c237335fddb
# Parent  fcf92c73da9d7fd61a4cdc525e877a7c9a9f603e
Trac #11763: Add ZZ as allowed base ring for polyhedra

diff --git a/doc/en/reference/geometry.rst b/doc/en/reference/geometry.rst
    a b  
    2525   sage/geometry/polyhedron/plot
    2626   sage/geometry/polyhedron/base
    2727   sage/geometry/polyhedron/base_QQ
     28   sage/geometry/polyhedron/base_ZZ
    2829   sage/geometry/polyhedron/base_RDF
    2930   sage/geometry/polyhedron/backend_cdd
    3031   sage/geometry/polyhedron/backend_ppl

  • sage/geometry/polyhedron/backend_ppl.py 

    diff --git a/sage/geometry/polyhedron/backend_ppl.py b/sage/geometry/polyhedron/backend_ppl.py
    a b  
    1111    Variable, Linear_Expression,
    1212    line, ray, point )
    1313
     14from base import Polyhedron_base
    1415from base_QQ import Polyhedron_QQ
     16from base_ZZ import Polyhedron_ZZ
    1517from representation import (
    1618    PolyhedronRepresentation,
    1719    Hrepresentation,
    … …  
    2224
    2325
    2426#########################################################################
    25 class Polyhedron_QQ_ppl(Polyhedron_QQ):
     27class Polyhedron_ppl(Polyhedron_base):
    2628    """
    27     Polyhedra over `\QQ` with ppl
     29    Polyhedra with ppl
    2830
    2931    INPUT:
    3032
    … …  
    6365        EXAMPLES::
    6466
    6567            sage: p = Polyhedron(backend='ppl')
    66             sage: from sage.geometry.polyhedron.backend_ppl import Polyhedron_QQ_ppl
    67             sage: Polyhedron_QQ_ppl._init_from_Vrepresentation(p, 2, [], [], [])
     68            sage: from sage.geometry.polyhedron.backend_ppl import Polyhedron_ppl
     69            sage: Polyhedron_ppl._init_from_Vrepresentation(p, 2, [], [], [])
    6870        """
    6971        gs = Generator_System()
    7072        if vertices is None: vertices = []
    … …  
    106108        EXAMPLES::
    107109
    108110            sage: p = Polyhedron(backend='ppl')
    109             sage: from sage.geometry.polyhedron.backend_ppl import Polyhedron_QQ_ppl
    110             sage: Polyhedron_QQ_ppl._init_from_Hrepresentation(p, 2, [], [])
     111            sage: from sage.geometry.polyhedron.backend_ppl import Polyhedron_ppl
     112            sage: Polyhedron_ppl._init_from_Hrepresentation(p, 2, [], [])
    111113        """
    112114        cs = Constraint_System()
    113115        if ieqs is None: ieqs = []
    … …  
    212214            The empty polyhedron in QQ^0
    213215            sage: Polyhedron(backend='ppl')._init_empty_polyhedron(0)
    214216        """
    215         super(Polyhedron_QQ_ppl, self)._init_empty_polyhedron(ambient_dim)
     217        super(Polyhedron_ppl, self)._init_empty_polyhedron(ambient_dim)
    216218        self._ppl_polyhedron = C_Polyhedron(ambient_dim, 'empty')
    217219
    218220
     221
     222
     223#########################################################################
     224class Polyhedron_QQ_ppl(Polyhedron_ppl, Polyhedron_QQ):
     225    """
     226    Polyhedra over `\QQ` with ppl
     227
     228    INPUT:
     229
     230    - ``ambient_dim`` -- integer. The dimension of the ambient space.
     231
     232    - ``Vrep`` -- a list ``[vertices, rays, lines]``.
     233       
     234    - ``Hrep`` -- a list ``[ieqs, eqns]``.
     235
     236    EXAMPLES::
     237
     238        sage: p = Polyhedron(vertices=[(0,0),(1,0),(0,1)], rays=[(1,1)], lines=[],
     239        ...                  backend='ppl', base_ring=QQ)
     240        sage: TestSuite(p).run(skip='_test_pickling')
     241    """
     242    pass
     243
     244
     245#########################################################################
     246class Polyhedron_ZZ_ppl(Polyhedron_ppl, Polyhedron_ZZ):
     247    """
     248    Polyhedra over `\ZZ` with ppl
     249
     250    INPUT:
     251
     252    - ``ambient_dim`` -- integer. The dimension of the ambient space.
     253
     254    - ``Vrep`` -- a list ``[vertices, rays, lines]``.
     255       
     256    - ``Hrep`` -- a list ``[ieqs, eqns]``.
     257
     258    EXAMPLES::
     259
     260        sage: p = Polyhedron(vertices=[(0,0),(1,0),(0,1)], rays=[(1,1)], lines=[])
     261        ...                  backend='ppl', base_ring=ZZ)
     262        sage: TestSuite(p).run(skip='_test_pickling')
     263    """
     264    pass

  • sage/geometry/polyhedron/base.py 

    diff --git a/sage/geometry/polyhedron/base.py b/sage/geometry/polyhedron/base.py
    a b  
    537537            desc += 'A ' + repr(self.dim()) + '-dimensional polyhedron'
    538538        desc += ' in '
    539539        if self.field()==QQ: desc += 'QQ'
    540         else:                desc += 'RDF'
     540        if   self.base_ring() is QQ:  desc += 'QQ'
     541        elif self.base_ring() is ZZ:  desc += 'ZZ'
     542        elif self.base_ring() is RDF: desc += 'RDF'
     543        else: assert False
    541544        desc += '^' + repr(self.ambient_dim())
    542545
    543546        if self.n_vertices()>0:
    … …  
    13501353            sage: poly_test.ambient_space()
    13511354            Vector space of dimension 4 over Rational Field
    13521355        """
    1353         from sage.modules.free_module import VectorSpace
    1354         return VectorSpace(self.base_ring(), self.ambient_dim())
     1356        from sage.modules.free_module import FreeModule
     1357        return FreeModule(self.base_ring(), self.ambient_dim())
    13551358
    13561359    Vrepresentation_space = ambient_space
    13571360

  • new file sage/geometry/polyhedron/base_ZZ.py 

    diff --git a/sage/geometry/polyhedron/base_ZZ.py b/sage/geometry/polyhedron/base_ZZ.py
new file mode 100644
    - +  
     1"""
     2Base class for polyhedra over `\ZZ`
     3"""
     4
     5########################################################################
     6#       Copyright (C) 2011 Volker Braun <vbraun.name@gmail.com>
     7#
     8#  Distributed under the terms of the GNU General Public License (GPL)
     9#
     10#                  http://www.gnu.org/licenses/
     11########################################################################
     12
     13
     14
     15from sage.rings.all import ZZ, QQ
     16from sage.misc.all import cached_method
     17from sage.matrix.constructor import matrix
     18
     19from constructor import Polyhedron
     20from base import Polyhedron_base
     21
     22
     23
     24#########################################################################
     25class Polyhedron_ZZ(Polyhedron_base):
     26    """
     27    Base class for Polyhedra over `\ZZ`
     28
     29    TESTS::
     30     
     31        sage: p = Polyhedron([(0,0)], base_ring=ZZ);  p
     32        A 0-dimensional polyhedron in ZZ^2 defined as the convex hull of 1 vertex
     33        sage: TestSuite(p).run(skip='_test_pickling')
     34    """
     35    def _is_zero(self, x):
     36        """
     37        Test whether ``x`` is zero.
     38       
     39        INPUT:
     40
     41        - ``x`` -- a number in the base ring.
     42
     43        OUTPUT:
     44
     45        Boolean.
     46
     47        EXAMPLES::
     48         
     49            sage: p = Polyhedron([(0,0)], base_ring=ZZ)
     50            sage: p._is_zero(0)
     51            True
     52            sage: p._is_zero(1/100000)
     53            False
     54        """
     55        return x==0
     56
     57    def _is_nonneg(self, x):
     58        """
     59        Test whether ``x`` is nonnegative.
     60       
     61        INPUT:
     62
     63        - ``x`` -- a number in the base ring.
     64
     65        OUTPUT:
     66
     67        Boolean.
     68
     69        EXAMPLES::
     70         
     71            sage: p = Polyhedron([(0,0)], base_ring=ZZ)
     72            sage: p._is_nonneg(1)
     73            True
     74            sage: p._is_nonneg(-1/100000)
     75            False
     76        """
     77        return x>=0
     78
     79    def _is_positive(self, x):
     80        """
     81        Test whether ``x`` is positive.
     82       
     83        INPUT:
     84
     85        - ``x`` -- a number in the base ring.
     86
     87        OUTPUT:
     88
     89        Boolean.
     90
     91        EXAMPLES::
     92         
     93            sage: p = Polyhedron([(0,0)], base_ring=ZZ)
     94            sage: p._is_positive(1)
     95            True
     96            sage: p._is_positive(0)
     97            False
     98        """
     99        return x>0
     100
     101    _base_ring = ZZ
     102     
     103    def is_lattice_polytope(self):
     104        r"""
     105        Return whether the polyhedron is a lattice polytope.
     106       
     107        OUTPUT:
     108
     109        ``True`` if the polyhedron is compact and has only integral
     110        vertices, ``False`` otherwise.
     111       
     112        EXAMPLES::
     113       
     114            sage: polytopes.cross_polytope(3).is_lattice_polytope()
     115            True
     116            sage: polytopes.regular_polygon(5).is_lattice_polytope()
     117            False
     118        """
     119        return True
     120
     121    @cached_method
     122    def polar(self):
     123        """
     124        Return the polar (dual) polytope.
     125
     126        The polytope must have the IP-property (see
     127        :meth:`has_IP_property`), that is, the origin must be an
     128        interior point. In particular, it must be full-dimensional.
     129
     130        OUTPUT:
     131
     132        The polytope whose vertices are the coefficient vectors of the
     133        inequalities of ``self`` with inhomogeneous term normalized to
     134        unity.
     135
     136        EXAMPLES::
     137
     138            sage: p = Polyhedron(vertices=[(1,0,0),(0,1,0),(0,0,1),(-1,-1,-1)], base_ring=ZZ)
     139            sage: p.polar()
     140            A 3-dimensional polyhedron in ZZ^3 defined as the convex hull of 4 vertices
     141            sage: type(_)
     142            <class 'sage.geometry.polyhedron.backend_ppl.Polyhedron_ZZ_ppl'>
     143            sage: p.polar().base_ring()
     144            Integer Ring
     145        """
     146        if not self.has_IP_property():
     147            raise ValueError('The polytope must have the IP property.')
     148
     149        vertices = [ ieq.A()/ieq.b() for
     150                     ieq in self.inequality_generator() ]
     151        if all( all(v_i in ZZ for v_i in v) for v in vertices):
     152            return Polyhedron(vertices=vertices, base_ring=ZZ)
     153        else:
     154            return Polyhedron(vertices=vertices, base_ring=QQ)
     155
     156    @cached_method
     157    def is_reflexive(self):
     158        """
     159        EXAMPLES::
     160
     161            sage: p = Polyhedron(vertices=[(1,0,0),(0,1,0),(0,0,1),(-1,-1,-1)], base_ring=ZZ)
     162            sage: p.is_reflexive()
     163            True
     164        """
     165        return self.polar().is_lattice_polytope()
     166
     167    @cached_method
     168    def has_IP_property(self):
     169        """
     170        Test whether the polyhedron has the IP property.
     171       
     172        The IP (interior point) property means that
     173       
     174        * ``self`` is compact (a polytope).
     175
     176        * ``self`` contains the origin.
     177
     178        This implies that
     179       
     180        * ``self`` is full-dimensional.
     181       
     182        * The dual polyhedron is again a polytope (that is, a compact
     183          polyhedron), though not necessarily a lattice polytope.
     184
     185        REFERENCES::
     186
     187        ..  [PALP]
     188            Maximilian Kreuzer, Harald Skarke:
     189            "PALP: A Package for Analyzing Lattice Polytopes
     190            with Applications to Toric Geometry"
     191            Comput.Phys.Commun. 157 (2004) 87-106
     192            http://arxiv.org/abs/math/0204356
     193        """
     194        return self.is_compact() and self.contains(self.ambient_space().zero())
     195
     196    def fibrations(self):
     197        """
     198        EXAMPLES::
     199
     200            sage: P = Polyhedron(toric_varieties.P4_11169().fan().rays(), base_ring=ZZ)
     201            sage: list( P.fibrations() )
     202            [A 2-dimensional polyhedron in QQ^4 defined as the convex hull of 3 vertices]
     203        """
     204        if not self.has_IP_property():
     205            raise ValueError('The polytope must have the IP property.')
     206        # todo: just go through pairs of points on the same facet
     207        fiber_dimension = 2
     208        points = self.integral_points()
     209        fibers = set()
     210        for i1 in range(0,len(points)):
     211            p1 = points[i1]
     212            if p1.is_zero():
     213                continue
     214            for i2 in range(i1+1,len(points)):
     215                p2 = points[i2]
     216                if p2.is_zero():
     217                    continue
     218                plane_12 = Polyhedron(lines=[p1,p2])
     219                if plane_12.dim() != 2:
     220                    continue
     221                fiber = self.intersection(plane_12)
     222                if not fiber.is_lattice_polytope():
     223                    continue
     224                fiber_matrix = matrix(ZZ,sorted(fiber.integral_points()))
     225                fiber_matrix.set_immutable()
     226                if fiber_matrix not in fibers:
     227                    yield fiber
     228                    fibers.update([fiber_matrix])
     229               
     230
     231
     232
     233       
     234     
     235
     236
     237

  • sage/geometry/polyhedron/constructor.py 

    diff --git a/sage/geometry/polyhedron/constructor.py b/sage/geometry/polyhedron/constructor.py
    a b  
    159159      * ``'cddf'``: cdd with floating-point coefficients
    160160
    161161      * ``'ppl'``: use ppl
    162         (:mod:`~sage.geometry.polyhedron.backend_ppl`) with `\QQ`
    163         coefficients.
     162        (:mod:`~sage.geometry.polyhedron.backend_ppl`) with `\QQ` or
     163        `\ZZ` coefficients depending on ``base_ring``.
    164164
    165165    Some backends support further optional arguments:
    166166
    … …  
    272272        ambient_dim = 0
    273273
    274274    if backend is not None:
    275         if backend=='ppl':
     275        if backend=='ppl' and base_ring is QQ:
    276276            from backend_ppl import Polyhedron_QQ_ppl
    277277            return Polyhedron_QQ_ppl(ambient_dim, Vrep, Hrep, minimize=minimize)
     278        if backend=='ppl' and base_ring is ZZ:
     279            from backend_ppl import Polyhedron_ZZ_ppl
     280            return Polyhedron_ZZ_ppl(ambient_dim, Vrep, Hrep, minimize=minimize)
    278281        if backend=='cddr':
    279282            from backend_cdd import Polyhedron_QQ_cdd
    280283            return Polyhedron_QQ_cdd(ambient_dim, Vrep, Hrep, verbose=verbose)
    281284        if backend=='cddf':
    282285            from backend_cdd import Polyhedron_RDF_cdd
    283286            return Polyhedron_RDF_cdd(ambient_dim, Vrep, Hrep, verbose=verbose)
     287        raise ValueError('No suitable backend implemented.')
    284288
    285289    if base_ring is QQ:
    286290        from backend_ppl import Polyhedron_QQ_ppl
    … …  
    288292    elif base_ring is RDF:
    289293        from backend_cdd import Polyhedron_RDF_cdd
    290294        return Polyhedron_RDF_cdd(ambient_dim, Vrep, Hrep, verbose=verbose)
     295    elif base_ring is ZZ:
     296        from backend_ppl import Polyhedron_ZZ_ppl
     297        return Polyhedron_ZZ_ppl(ambient_dim, Vrep, Hrep, minimize=minimize)
    291298    else:
    292299        raise ValueError('Polyhedron objects can only be constructed over QQ and RDF')
    293300

  • sage/geometry/polyhedron/representation.py 

    diff --git a/sage/geometry/polyhedron/representation.py b/sage/geometry/polyhedron/representation.py
    a b  
    6060            (1, 2, 3)
    6161            sage: TestSuite(pr).run(skip='_test_pickling')
    6262        """
    63         self._representation_data = tuple(data)
     63        R = polyhedron.base_ring()
     64        self._representation_data = tuple(R(x) for x in data)
    6465        self._polyhedron = polyhedron
    6566
    6667    def __len__(self):