Ticket #9972: trac_9972_remove_enhanced_cones_and_fans.patch

sage/geometry/fan.py

@@ -2389 +2389 @@
             gens.append( sum([ self.ray(i)[d] * ring.gen(i) 
                                for i in range(0, self.nrays()) ]) )
         return ring.ideal(gens)
-
-
-class EnhancedCone(Cone_of_fan):
-    r"""
-    Construct an enhanced cone.
-
-    Enhanced cones are similar to "regular" :class:`convex rational polyhedral
-    cones <sage.geometry.cone.ConvexRationalPolyhedralCone>` or, more
-    precisely, to :class:`cones of fans <Cone_of_fan>`, but may have some
-    extra functionality. :class:`EnhancedCone` class by itself does not
-    provide any of such extra functionality, but in conjunction with
-    :class:`EnhancedFan` allows convenient derivation of new classes and
-    ensures CPU- and memory-efficient interaction between regular cones and
-    their enhanced copies.
-
-    INPUT:
-
-    - ``cone`` -- :class:`Cone_of_fan`;
-
-    - ``ambient`` -- ambient fan of this cone. If not given, will be the same
-      as for ``cone``;
-
-    OR (these parameters must be given as keywords):
-
-    - ``ambient`` -- ambient fan of this cone;
-
-    - ``ambient_ray_indices`` -- increasing list or tuple of integers, indices
-      of rays of ``ambient`` generating this cone.
-
-    OUTPUT:
-
-    - enhanced cone of exactly the same structure as ``cone``.
-
-    EXAMPLES::
-
-        sage: from sage.geometry.fan import EnhancedCone
-        sage: fan = FaceFan(lattice_polytope.octahedron(2))
-        sage: econe = EnhancedCone(fan.generating_cone(0))
-        sage: econe == fan.generating_cone(0)
-        True
-        sage: econe is fan.generating_cone(0)
-        False
-    """
-
-    def __init__(self, cone=None, ambient=None, ambient_ray_indices=None):
-        r"""
-        See :class:`EnhancedCone` for documentation.
-
-        TESTS::
-
-            sage: from sage.geometry.fan import EnhancedCone
-            sage: fan = FaceFan(lattice_polytope.octahedron(2))
-            sage: econe = EnhancedCone(fan.generating_cone(0))
-            sage: econe == fan.generating_cone(0)
-            True
-            sage: econe is fan.generating_cone(0)
-            False
-            sage: TestSuite(econe).run()
-        """
-        if cone is None:
-            # Then both other attributes must be given and we can make cone
-            # We try to keep "the level of enhancement" the same for all cones
-            # of the same ambient
-            base = ambient._base_fan if is_EnhancedFan(ambient) else ambient
-            if is_EnhancedFan(base):
-                cone_type = base._cone_type
-            elif is_Fan(base):
-                cone_type = Cone_of_fan
-            else:
-                cone_type = ConvexRationalPolyhedralCone
-            cone = cone_type(ambient=base,
-                             ambient_ray_indices=ambient_ray_indices)
-        for attribute in [# Cone attributes
-                          "_rays",
-                          "_lattice",
-                          # _ambient will be set later
-                          "_ambient_ray_indices",
-                          # Cached attributes copied for efficiency
-                          "_is_strictly_convex"]:
-            setattr(self, attribute, getattr(cone, attribute))
-        self._ambient = ambient if ambient is not None else cone.ambient()
-
-
-def is_EnhancedCone(x):
-    r"""
-    Check if ``x`` is an enhanced cone.
-
-    INPUT:
-
-    - ``x`` -- anything.
-
-    OUTPUT:
-
-    - ``True`` if ``x`` is an enhanced cone and ``False`` otherwise.
-
-    EXAMPLES::
-
-        sage: from sage.geometry.fan import (
-        ...     EnhancedCone, is_EnhancedCone)
-        sage: is_EnhancedCone(1)
-        False
-        sage: cone = Cone([(1,0), (0,1)])
-        sage: is_EnhancedCone(cone)
-        False
-        sage: fan = FaceFan(lattice_polytope.octahedron(2))
-        sage: econe = EnhancedCone(fan.generating_cone(0))
-        sage: is_EnhancedCone(econe)
-        True
-    """
-    return isinstance(x, EnhancedCone)
-
-
-class EnhancedFan(RationalPolyhedralFan):
-    r"""
-    Construct an enhanced fan.
-
-    Enhanced fans are similar to "regular" :class:`rational polyhedral fans
-    <RationalPolyhedralFan>`, but may have some extra functionality on the
-    levels of fans themselves as well as their cones. :class:`EnhancedFan`
-    class by itself does not provide any extra functionality, but allows
-    convenient derivation of new classes and ensures CPU- and memory-efficient
-    interaction between regular fans and their enhanced copies.
-
-    INPUT:
-
-    - ``fan`` -- :class:`rational polyhedral fan <RationalPolyhedralFan>`;
-
-    - ``cone_type`` -- class derived from :class:`EnhancedCone`.
-
-    OUTPUT:
-
-    - enhanced fan of exactly the same structure as ``fan``, but all of its
-      associated cones are objects of ``cone_type``.
-
-    EXAMPLES::
-
-        sage: from sage.geometry.fan import (
-        ...     EnhancedCone, EnhancedFan, is_EnhancedCone)
-        sage: fan = FaceFan(lattice_polytope.octahedron(2))
-        sage: efan = EnhancedFan(fan, EnhancedCone)
-        sage: is_EnhancedCone(efan.generating_cone(0))
-        True
-    """
-
-    def __init__(self, fan, cone_type):
-        r"""
-        See :class:`EnhancedFan` for documentation.
-
-        TESTS::
-
-            sage: from sage.geometry.fan import (
-            ...     EnhancedCone, EnhancedFan, is_EnhancedCone)
-            sage: fan = FaceFan(lattice_polytope.octahedron(2))
-            sage: efan = EnhancedFan(fan, EnhancedCone)
-            sage: is_EnhancedCone(efan.generating_cone(0))
-            True
-            sage: TestSuite(efan).run()
-        """
-        for attribute in [# Fan attributes
-                          "_rays",
-                          "_lattice"]:
-            setattr(self, attribute, getattr(fan, attribute))
-        self._base_fan = fan
-        self._cone_type = cone_type
-        self._generating_cones = tuple(cone_type(cone, self) for cone in fan)
-
-    def _compute_cone_lattice(self):
-        r"""
-        Compute the cone lattice of ``self``.
-
-        See :meth:`~RationalPolyhedralFan.cone_lattice` for documentation.
-
-        TESTS::
-
-            sage: from sage.geometry.fan import (
-            ...     EnhancedCone, EnhancedFan, is_EnhancedCone)
-            sage: fan = FaceFan(lattice_polytope.octahedron(2))
-            sage: efan = EnhancedFan(fan, EnhancedCone)
-            sage: L = efan.cone_lattice() # indirect doctest
-            sage: L
-            Finite poset containing 10 elements
-            sage: is_EnhancedCone(L[0].element)
-            True
-        """
-        # Actual computation of the lattice is done in the "usual" fan
-        L =  self._base_fan.cone_lattice()
-        # We just copy its structure using the appropriate class for cones
-        elements = []
-        for element in L:
-            cone = element.element
-            if is_Cone(cone):
-                elements.append(self._cone_type(cone, ambient=self))
-            else:
-                # The last element is the fan itself
-                elements.append(self)
-        self._cone_lattice = FinitePoset(L, elements)
-
-
-def is_EnhancedFan(x):
-    r"""
-    Check if ``x`` is an enhanced fan.
-
-    INPUT:
-
-    - ``x`` -- anything.
-
-    OUTPUT:
-
-    - ``True`` if ``x`` is an enhanced fan and ``False`` otherwise.
-
-    EXAMPLES::
-
-        sage: from sage.geometry.fan import (
-        ...     EnhancedCone, EnhancedFan, is_EnhancedFan)
-        sage: is_EnhancedFan(1)
-        False
-        sage: fan = FaceFan(lattice_polytope.octahedron(2))
-        sage: is_EnhancedFan(fan)
-        False
-        sage: efan = EnhancedFan(fan, EnhancedCone)
-        sage: is_EnhancedFan(efan)
-        True
-    """
-    return isinstance(x, EnhancedFan)

sage/schemes/generic/toric_variety.py

@@ -230 +230 @@
 #*****************************************************************************
 
 from sage.geometry.cone import Cone, is_Cone
-from sage.geometry.fan import Fan, EnhancedCone, EnhancedFan, is_EnhancedFan
+from sage.geometry.fan import Fan
 from sage.matrix.all import matrix
 from sage.misc.all import latex, prod
 from sage.modules.free_module_element import vector
@@ -252 +252 @@
 DEFAULT_PREFIX = "z"
 
 
-class Cone_of_toric_variety(EnhancedCone):
-    r"""
-    Construct a cone associated to a toric variety.
-
-    INPUT:
-
-    - same as for :class:`~sage.geometry.fan.EnhancedCone`.
-
-    TESTS::
-
-        sage: cone = Cone([(1,2), (3,4)])
-        sage: X = AffineToricVariety(cone)
-        sage: Xcone = X.fan().generating_cone(0)
-        sage: Xcone == cone
-        True
-        sage: Xcone.toric_variety()
-        2-d affine toric variety
-        sage: cone.toric_variety()
-        Traceback (most recent call last):
-        ...
-        AttributeError: 'ConvexRationalPolyhedralCone'
-        object has no attribute 'toric_variety'
-        """
-
-    def toric_variety(self):
-        r"""
-        Return the toric variety associated to ``self``.
-
-        OUTPUT:
-
-        - :class:`toric variety <ToricVariety_field>`.
-
-        EXAMPLES::
-
-            sage: cone = Cone([(1,2), (3,4)])
-            sage: X = AffineToricVariety(cone)
-            sage: Xcone = X.fan().generating_cone(0)
-            sage: Xcone.toric_variety()
-            2-d affine toric variety
-        """
-        return self.ambient().toric_variety()
-
-
-class Fan_of_toric_variety(EnhancedFan):
-    r"""
-    Construct a fan associated to a toric variety.
-
-    This class binds an existing fan to a toric variety: the constructed fan
-    is exactly the same as the input one, but it (and all of its cones) will
-    know the associated toric variety.
-
-    INPUT:
-
-    - ``fan`` -- :class:`rational polyhedral fan
-      <sage.geometry.fan.RationalPolyhedralFan>`;
-
-    - ``toric_variety`` -- :class:`toric variety <ToricVariety_field>`.
-
-    TESTS::
-
-        sage: fan = FaceFan(lattice_polytope.octahedron(3))
-        sage: P = ToricVariety(fan)
-        sage: P.fan() == fan
-        True
-        sage: P.fan().toric_variety()
-        3-d toric variety covered by 8 affine patches
-        sage: fan.toric_variety()
-        Traceback (most recent call last):
-        ...
-        AttributeError: 'RationalPolyhedralFan'
-        object has no attribute 'toric_variety'
-    """
-
-    def __init__(self, fan, toric_variety):
-        r"""
-        See :class:`Fan_of_toric_variety` for documentation.
-
-        TESTS::
-
-            sage: fan = FaceFan(lattice_polytope.octahedron(3))
-            sage: P = ToricVariety(fan)
-            sage: P.fan() == fan
-            True
-            sage: P.fan().toric_variety()
-            3-d toric variety covered by 8 affine patches
-            sage: fan.toric_variety()
-            Traceback (most recent call last):
-            ...
-            AttributeError: 'RationalPolyhedralFan'
-            object has no attribute 'toric_variety'
-
-        Check that newly constructed cones have appropriate type::
-        
-            sage: P2 = toric_varieties.P2()
-            sage: c = P2.fan().cone_containing((0,1))
-            sage: type(c)
-            <class 'sage.schemes.generic.toric_variety.Cone_of_toric_variety'>
-        """
-        # Strip all existing enhancements
-        while is_EnhancedFan(fan):
-            fan = fan._base_fan
-        super(Fan_of_toric_variety, self).__init__(fan, Cone_of_toric_variety)
-        self._toric_variety = toric_variety
-
-    def toric_variety(self):
-        r"""
-        Return the toric variety associated to ``self``.
-
-        OUTPUT:
-
-        - :class:`toric variety <ToricVariety_field>`.
-
-        EXAMPLES::
-
-            sage: fan = FaceFan(lattice_polytope.octahedron(3))
-            sage: P = ToricVariety(fan)
-            sage: P.fan().toric_variety()
-            3-d toric variety covered by 8 affine patches
-        """
-        return self._toric_variety
-
-
 def is_ToricVariety(x):
     r"""
     Check if ``x`` is a toric variety.
@@ -576 +454 @@
             sage: fan = FaceFan(lattice_polytope.octahedron(2))
             sage: P1xP1 = ToricVariety(fan)
         """
-        self._fan = Fan_of_toric_variety(fan, self)
+        self._fan = fan
         super(ToricVariety_field, self).__init__(fan.lattice_dim(),
                                                  base_field)
         self._torus_factor_dim = fan.lattice_dim() - fan.dim()
@@ -1124 +1002 @@
             sage: P1xP1 = ToricVariety(fan)
             sage: P1xP1.fan()
             Rational polyhedral fan in 2-d lattice N
-            sage: P1xP1.fan() == fan
+            sage: P1xP1.fan() is fan
             True
             sage: P1xP1.fan(1)[0]
             1-d cone of Rational polyhedral fan in 2-d lattice N