Deprecate is_Fan, is_NefPartition, is_PointCollection, is_ToricLattice, is_ToricLatticeElement, is_ToricLatticeQuotient

src/sage/geometry/cone.py

@@ -212,8 +212,8 @@
 from sage.geometry.point_collection import PointCollection
 from sage.geometry.polyhedron.constructor import Polyhedron
 from sage.geometry.hasse_diagram import lattice_from_incidences
-from sage.geometry.toric_lattice import (ToricLattice, is_ToricLattice,
-                                         is_ToricLatticeQuotient)
+from sage.geometry.toric_lattice import (ToricLattice, ToricLattice_generic,
+                                         ToricLattice_quotient)
 from sage.geometry.toric_plotter import ToricPlotter, label_list
 from sage.geometry.relative_interior import RelativeInterior
 from sage.graphs.digraph import DiGraph
@@ -471,7 +471,7 @@ def Cone(rays, lattice=None, check=True, normalize=True):
     if not check or not rays:
         return ConvexRationalPolyhedralCone(rays, lattice)
     # Any set of rays forms a cone, but we want to keep only generators
-    if is_ToricLatticeQuotient(lattice):
+    if isinstance(lattice, ToricLattice_quotient):
         gs = Generator_System(
                         PPL_point(Linear_Expression(lattice(0).vector(), 0)))
         for r in rays:
@@ -620,7 +620,7 @@ def try_base_extend(ring):
     p = try_base_extend(ZZ)
     if p is not None:
         return p
-    if is_ToricLattice(parent(data)):
+    if isinstance(parent(data), ToricLattice_generic):
         raise TypeError("the point %s and %s have incompatible "
                         "lattices" % (data, body))
 
@@ -720,7 +720,7 @@ def normalize_rays(rays, lattice):
     if rays:
         if lattice is None:
             ray_parent = parent(rays[0])
-            lattice = (ray_parent if is_ToricLattice(ray_parent)
+            lattice = (ray_parent if isinstance(ray_parent, ToricLattice_generic)
                                   else ToricLattice(len(rays[0])))
         if lattice.base_ring() is not ZZ:
             raise TypeError("lattice must be a free module over ZZ")
@@ -2006,7 +2006,7 @@ def _repr_(self):
         result = "%d-d" % self.dim()
         if self.ambient() is self:
             result += " cone in"
-            if is_ToricLattice(self.lattice()):
+            if isinstance(self.lattice(), ToricLattice_generic):
                 result += " %s" % self.lattice()
             else:
                 result += " %d-d lattice" % self.lattice_dim()
@@ -3661,7 +3661,7 @@ def strict_quotient(self):
         # for sublattices. But it seems to be the most natural choice
         # for names. If many subcones land in the same lattice -
         # that's just how it goes.
-        if is_ToricLattice(L):
+        if isinstance(L, ToricLattice_generic):
             S = ToricLattice(Q.dimension(), L._name, L._dual_name,
                              L._latex_name, L._latex_dual_name)
         else:

src/sage/geometry/fan.py

@@ -250,7 +250,7 @@
                                 normalize_rays)
 from sage.geometry.hasse_diagram import lattice_from_incidences
 from sage.geometry.point_collection import PointCollection
-from sage.geometry.toric_lattice import ToricLattice, is_ToricLattice
+from sage.geometry.toric_lattice import ToricLattice, ToricLattice_generic
 from sage.geometry.toric_plotter import ToricPlotter
 from sage.graphs.digraph import DiGraph
 from sage.matrix.constructor import matrix
@@ -279,12 +279,19 @@ def is_Fan(x) -> bool:
 
         sage: from sage.geometry.fan import is_Fan
         sage: is_Fan(1)
+        doctest:warning...
+        DeprecationWarning: The function is_Fan is deprecated; use 'isinstance(..., RationalPolyhedralFan)' instead.
+        See https://github.com/sagemath/sage/issues/38126 for details.
         False
         sage: fan = toric_varieties.P2().fan(); fan                                     # needs palp
         Rational polyhedral fan in 2-d lattice N
         sage: is_Fan(fan)                                                               # needs palp
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38126,
+                "The function is_Fan is deprecated; "
+                "use 'isinstance(..., RationalPolyhedralFan)' instead.")
     return isinstance(x, RationalPolyhedralFan)
 
 
@@ -1330,7 +1337,7 @@ def __richcmp__(self, right, op):
             sage: f2 is f3
             False
         """
-        if is_Fan(right):
+        if isinstance(right, RationalPolyhedralFan):
             return richcmp([self.rays(), self.virtual_rays(),
                             self.generating_cones()],
                            [right.rays(), right.virtual_rays(),
@@ -1397,7 +1404,7 @@ def _compute_cone_lattice(self):
         not even need to check if it is complete::
 
             sage: fan = toric_varieties.P1xP1().fan()                                   # needs palp
-            sage: fan.cone_lattice() # indirect doctest                                 # needs palp
+            sage: fan.cone_lattice()  # indirect doctest                                # needs palp
             Finite lattice containing 10 elements with distinguished linear extension
 
         These 10 elements are: 1 origin, 4 rays, 4 generating cones, 1 fan.
@@ -1679,7 +1686,7 @@ def cartesian_product(self, other, lattice=None):
             sage: _.ngenerating_cones()
             6
         """
-        assert is_Fan(other)
+        assert isinstance(other, RationalPolyhedralFan)
         rc = super().cartesian_product(other, lattice)
         self_cones = [cone.ambient_ray_indices() for cone in self]
         n = self.nrays()
@@ -1859,7 +1866,7 @@ def _repr_(self) -> str:
             'Rational polyhedral fan in 2-d lattice'
         """
         result = "Rational polyhedral fan in"
-        if is_ToricLattice(self.lattice()):
+        if isinstance(self.lattice(), ToricLattice_generic):
             result += " %s" % self.lattice()
         else:
             result += " %d-d lattice" % self.lattice_dim()

src/sage/geometry/fan_morphism.py

@@ -80,7 +80,7 @@
 
 from sage.categories.homset import Hom
 from sage.geometry.cone import Cone
-from sage.geometry.fan import Fan, is_Fan
+from sage.geometry.fan import Fan, RationalPolyhedralFan
 from sage.matrix.constructor import matrix
 from sage.matrix.special import identity_matrix
 from sage.structure.element import is_Matrix
@@ -270,8 +270,8 @@ def __init__(self, morphism, domain_fan,
             Codomain fan: Rational polyhedral fan in 2-d lattice N
             sage: TestSuite(fm).run(skip="_test_category")
         """
-        assert is_Fan(domain_fan)
-        if is_Fan(codomain):
+        assert isinstance(domain_fan, RationalPolyhedralFan)
+        if isinstance(codomain, RationalPolyhedralFan):
             codomain, codomain_fan = codomain.lattice(), codomain
         else:
             codomain_fan = None

src/sage/geometry/lattice_polytope.py

@@ -127,9 +127,8 @@
 from sage.geometry.cone import _ambient_space_point, integral_length
 from sage.geometry.hasse_diagram import lattice_from_incidences
 from sage.geometry.point_collection import (PointCollection,
-                                            is_PointCollection,
                                             read_palp_point_collection)
-from sage.geometry.toric_lattice import ToricLattice, is_ToricLattice
+from sage.geometry.toric_lattice import ToricLattice, ToricLattice_generic
 from sage.groups.perm_gps.permgroup_named import SymmetricGroup
 
 from sage.misc.lazy_import import lazy_import
@@ -318,7 +317,7 @@ def LatticePolytope(data, compute_vertices=True, n=0, lattice=None):
     if isinstance(data, LatticePolytopeClass):
         data = data._vertices
         compute_vertices = False
-    if (is_PointCollection(data) and
+    if (isinstance(data, PointCollection) and
         (lattice is None or lattice is data.module())):
         return LatticePolytopeClass(data, compute_vertices)
     if isinstance(data, str):
@@ -328,7 +327,7 @@ def LatticePolytope(data, compute_vertices=True, n=0, lattice=None):
         f.close()
     if isinstance(data, (IOBase, StringIO)):
         data = read_palp_point_collection(data)
-    if not is_PointCollection(data) and not isinstance(data, (list, tuple)):
+    if not isinstance(data, PointCollection) and not isinstance(data, (list, tuple)):
         try:
             data = list(data)
         except TypeError:
@@ -338,7 +337,7 @@ def LatticePolytope(data, compute_vertices=True, n=0, lattice=None):
             raise ValueError("lattice must be given explicitly for "
                              "empty polytopes!")
         try:
-            if is_ToricLattice(data[0].parent()):
+            if isinstance(data[0].parent(), ToricLattice_generic):
                 lattice = data[0].parent()
         except AttributeError:
             pass
@@ -934,7 +933,7 @@ def _embed(self, data):
             return data
         self._compute_embedding()
         M = self.lattice()
-        if is_PointCollection(data):
+        if isinstance(data, PointCollection):
             r = [M(self._embedding_matrix * point + self._shift_vector)
                  for point in data]
             for point in r:
@@ -1103,7 +1102,7 @@ def _pullback(self, data):
         self._compute_embedding()
         if data is self._vertices:
             return self._sublattice_polytope._vertices
-        if is_PointCollection(data):
+        if isinstance(data, PointCollection):
             r = [self._pullback(point) for point in data]
             for point in r:
                 point.set_immutable()
@@ -1334,7 +1333,7 @@ def _repr_(self):
                         parts.insert(-1, "#%d" % self.index())
             except ValueError:
                 pass
-            if is_ToricLattice(self.lattice()):
+            if isinstance(self.lattice(), ToricLattice_generic):
                 parts.append(str(self.lattice()))
             else:
                 parts.append("%d-d lattice" % self.lattice_dim())
@@ -4199,15 +4198,19 @@ def is_NefPartition(x):
 
     EXAMPLES::
 
-        sage: from sage.geometry.lattice_polytope import is_NefPartition
-        sage: is_NefPartition(1)
+        sage: from sage.geometry.lattice_polytope import NefPartition
+        sage: isinstance(1, NefPartition)
         False
         sage: o = lattice_polytope.cross_polytope(3)
         sage: np = o.nef_partitions()[0]; np                                            # needs palp
         Nef-partition {0, 1, 3} ⊔ {2, 4, 5}
-        sage: is_NefPartition(np)                                                       # needs palp
+        sage: isinstance(np, NefPartition)                                                       # needs palp
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38126,
+                "The function is_NefPartition is deprecated; "
+                "use 'isinstance(..., NefPartition)' instead.")
     return isinstance(x, NefPartition)
 
 
@@ -4408,7 +4411,7 @@ def __eq__(self, other):
             sage: np == 0
             False
         """
-        return (is_NefPartition(other)
+        return (isinstance(other, NefPartition)
                 and self._Delta_polar == other._Delta_polar
                 and self._vertex_to_part == other._vertex_to_part)
 
@@ -5989,7 +5992,7 @@ def write_palp_matrix(m, ofile=None, comment="", format=None):
            0    1    0    0   -1    0
            0    0    1    0    0   -1
     """
-    if is_PointCollection(m):
+    if isinstance(m, PointCollection):
         m = m.column_matrix()
     if format is None:
         n = max(len(str(m[i,j]))

src/sage/geometry/point_collection.pyx

@@ -98,13 +98,17 @@ def is_PointCollection(x):
 
     EXAMPLES::
 
-        sage: from sage.geometry.point_collection import is_PointCollection
-        sage: is_PointCollection(1)
+        sage: from sage.geometry.point_collection import PointCollection
+        sage: isinstance(1, PointCollection)
         False
         sage: c = Cone([(0,0,1), (1,0,1), (0,1,1), (1,1,1)])
-        sage: is_PointCollection(c.rays())
+        sage: isinstance(c.rays(), PointCollection)
         True
     """
+    from sage.misc.superseded import deprecation_cython
+    deprecation_cython(38126,
+                       "The function is_PointCollection is deprecated; "
+                       "use 'isinstance(..., PointCollection)' instead.")
     return isinstance(x, PointCollection)
 
 
@@ -665,7 +669,7 @@ cdef class PointCollection(SageObject):
             N+N(1, 1, 1, 1, 1, 1)
             in 6-d lattice N+N
         """
-        assert is_PointCollection(other)
+        assert isinstance(other, PointCollection)
         if module is None:
             module = self._module.direct_sum(other.module())
         P = [list(p) for p in self]

src/sage/geometry/toric_lattice.py

@@ -145,8 +145,7 @@
 #                  https://www.gnu.org/licenses/
 # ****************************************************************************
 
-from sage.geometry.toric_lattice_element import (ToricLatticeElement,
-                                                 is_ToricLatticeElement)
+from sage.geometry.toric_lattice_element import ToricLatticeElement
 from sage.geometry.toric_plotter import ToricPlotter
 from sage.misc.latex import latex
 from sage.structure.all import parent
@@ -180,13 +179,21 @@ def is_ToricLattice(x):
         sage: from sage.geometry.toric_lattice import (
         ....:   is_ToricLattice)
         sage: is_ToricLattice(1)
+        doctest:warning...
+        DeprecationWarning: The function is_ToricLattice is deprecated;
+        use 'isinstance(..., ToricLattice_generic)' instead.
+        See https://github.com/sagemath/sage/issues/38126 for details.
         False
         sage: N = ToricLattice(3)
         sage: N
         3-d lattice N
         sage: is_ToricLattice(N)
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38126,
+                "The function is_ToricLattice is deprecated; "
+                "use 'isinstance(..., ToricLattice_generic)' instead.")
     return isinstance(x, ToricLattice_generic)
 
 
@@ -207,6 +214,10 @@ def is_ToricLatticeQuotient(x):
         sage: from sage.geometry.toric_lattice import (
         ....:   is_ToricLatticeQuotient)
         sage: is_ToricLatticeQuotient(1)
+        doctest:warning...
+        DeprecationWarning: The function is_ToricLatticeQuotient is deprecated;
+        use 'isinstance(..., ToricLattice_quotient)' instead.
+        See https://github.com/sagemath/sage/issues/38126 for details.
         False
         sage: N = ToricLattice(3)
         sage: N
@@ -220,6 +231,10 @@ def is_ToricLatticeQuotient(x):
         sage: is_ToricLatticeQuotient(Q)
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38126,
+                "The function is_ToricLatticeQuotient is deprecated; "
+                "use 'isinstance(..., ToricLattice_quotient)' instead.")
     return isinstance(x, ToricLattice_quotient)
 
 
@@ -445,7 +460,7 @@ def __call__(self, *args, **kwds):
             coordinates = [ZZ(_) for _ in args]
         except TypeError:
             # Prohibit conversion of elements of other lattices
-            if (is_ToricLatticeElement(args[0])
+            if (isinstance(args[0], ToricLatticeElement)
                 and args[0].parent().ambient_module()
                 is not self.ambient_module()):
                 raise TypeError("%s cannot be converted to %s!"
@@ -471,7 +486,7 @@ def _coerce_map_from_(self, other):
             TypeError: N(1, 2, 3) cannot be converted to 3-d lattice M!
 
         """
-        if (is_ToricLattice(other) and
+        if (isinstance(other, ToricLattice_generic) and
             other.ambient_module() is not self.ambient_module()):
             return None
         return super()._convert_map_from_(other)
@@ -624,14 +639,14 @@ def intersection(self, other):
             True
         """
         # Lattice-specific input check
-        if not is_ToricLattice(other):
+        if not isinstance(other, ToricLattice_generic):
             raise TypeError("%s is not a toric lattice!" % other)
         if self.ambient_module() != other.ambient_module():
             raise ValueError("%s and %s have different ambient lattices!" %
                              (self, other))
         # Construct a generic intersection, but make sure to return a lattice.
         I = super().intersection(other)
-        if not is_ToricLattice(I):
+        if not isinstance(I, ToricLattice_generic):
             I = self.ambient_module().submodule(I.basis())
         return I
 
@@ -756,7 +771,7 @@ def saturation(self):
             True
         """
         S = super().saturation()
-        return S if is_ToricLattice(S) else self.ambient_module().submodule(S)
+        return S if isinstance(S, ToricLattice_generic) else self.ambient_module().submodule(S)
 
     def span(self, gens, base_ring=ZZ, *args, **kwds):
         r"""
@@ -799,7 +814,7 @@ def span(self, gens, base_ring=ZZ, *args, **kwds):
         if base_ring is ZZ and all(g in A for g in gens):
             return ToricLattice_sublattice(A, gens)
         for g in gens:
-            if is_ToricLatticeElement(g) and g not in A:
+            if isinstance(g, ToricLatticeElement) and g not in A:
                 raise ValueError("%s cannot generate a sublattice of %s"
                                  % (g, A))
         return super().span(gens, base_ring, *args, **kwds)
@@ -853,7 +868,7 @@ def span_of_basis(self, basis, base_ring=ZZ, *args, **kwds):
         if base_ring is ZZ and all(g in A for g in basis):
             return ToricLattice_sublattice_with_basis(A, basis)
         for g in basis:
-            if is_ToricLatticeElement(g) and g not in A:
+            if isinstance(g, ToricLatticeElement) and g not in A:
                 raise ValueError("%s cannot generate a sublattice of %s"
                                  % (g, A))
         return super().span_of_basis(basis, base_ring, *args, **kwds)