Trac #33452: adjust error messages in topology/

as in #33367

plus a few other details about https and pep8

URL: https://trac.sagemath.org/33452
Reported by: chapoton
Ticket author(s): Frédéric Chapoton
Reviewer(s): Matthias Koeppe

Author: Release Manager

src/sage/topology/cell_complex.py

@@ -41,7 +41,7 @@
 #  as published by the Free Software Foundation; either version 2 of
 #  the License, or (at your option) any later version.
 #
-#                  http://www.gnu.org/licenses/
+#                  https://www.gnu.org/licenses/
 ########################################################################
 
 from sage.structure.sage_object import SageObject
@@ -1002,7 +1002,7 @@ def cohomology_ring(self, base_ring=QQ):
             sage: T.cohomology_ring()
             Traceback (most recent call last):
             ...
-            ValueError: This simplicial complex must be immutable. Call set_immutable().
+            ValueError: this simplicial complex must be immutable; call set_immutable()
             sage: T.set_immutable()
             sage: T.cohomology_ring()
             Cohomology ring of Simplicial complex with 9 vertices and
@@ -1226,5 +1226,3 @@ def _repr_(self):
         else:
             cells_string = " and 1 %s" % cell_name
         return Name + " complex " + vertex_string + cells_string
-
-

src/sage/topology/cubical_complex.py

@@ -145,17 +145,17 @@ def __init__(self, data):
                 try:
                     Integer(x[0])
                 except TypeError:
-                    raise ValueError("The interval %s is not of the correct form" % x)
+                    raise ValueError("the interval %s is not of the correct form" % x)
                 if x[0] + 1 == x[1]:
                     nondegenerate.append(i)
                 elif x[0] != x[1]:
-                    raise ValueError("The interval %s is not of the correct form" % x)
+                    raise ValueError("the interval %s is not of the correct form" % x)
                 new_data.append(tuple(x))
             elif len(x) == 1:
                 y = tuple(x)
                 new_data.append(y+y)
             elif len(x) != 1:
-                raise ValueError("The interval %s is not of the correct form" % x)
+                raise ValueError("the interval %s is not of the correct form" % x)
             i += 1
         self.__tuple = tuple(new_data)
         self.__nondegenerate = nondegenerate
@@ -356,10 +356,10 @@ def face(self, n, upper=True):
             sage: C.face(3)
             Traceback (most recent call last):
             ...
-            ValueError: Can only compute the nth face if 0 <= n < dim.
+            ValueError: can only compute the nth face if 0 <= n < dim
         """
         if n < 0 or n >= self.dimension():
-            raise ValueError("Can only compute the nth face if 0 <= n < dim.")
+            raise ValueError("can only compute the nth face if 0 <= n < dim")
         idx = self.nondegenerate_intervals()[n]
         t = self.__tuple
         if upper:
@@ -456,7 +456,7 @@ def _compare_for_gluing(self, other):
         """
         d = self.dimension()
         if d != other.dimension():
-            raise ValueError("Cubes must be of the same dimension.")
+            raise ValueError("cubes must be of the same dimension")
         insert_self = []
         insert_other = []
         translate = []
@@ -847,7 +847,7 @@ class :class:`Cube`, or lists or tuples suitable for conversion to
         sage: S1.join(S1)
         Traceback (most recent call last):
         ...
-        NotImplementedError: Joins are not implemented for cubical complexes.
+        NotImplementedError: joins are not implemented for cubical complexes
 
     Therefore, neither are cones or suspensions.
     """
@@ -1065,7 +1065,7 @@ def cells(self, subcomplex=None):
         if subcomplex not in self._cells:
             if subcomplex is not None and subcomplex.dimension() > -1:
                 if not subcomplex.is_subcomplex(self):
-                    raise ValueError("The 'subcomplex' is not actually a subcomplex.")
+                    raise ValueError("the 'subcomplex' is not actually a subcomplex")
             # Cells is the dictionary of cells in self but not in
             # subcomplex, indexed by dimension
             Cells = {}
@@ -1381,9 +1381,9 @@ def join(self, other):
             sage: C1.join(C1)
             Traceback (most recent call last):
             ...
-            NotImplementedError: Joins are not implemented for cubical complexes.
+            NotImplementedError: joins are not implemented for cubical complexes
         """
-        raise NotImplementedError("Joins are not implemented for cubical complexes.")
+        raise NotImplementedError("joins are not implemented for cubical complexes")
 
     # Use * to mean 'join':
     # __mul__ = join
@@ -1405,10 +1405,10 @@ def cone(self):
             sage: C1.cone()
             Traceback (most recent call last):
             ...
-            NotImplementedError: Cones are not implemented for cubical complexes.
+            NotImplementedError: cones are not implemented for cubical complexes
         """
-        #return self.join(cubical_complexes.Cube(0))
-        raise NotImplementedError("Cones are not implemented for cubical complexes.")
+        # return self.join(cubical_complexes.Cube(0))
+        raise NotImplementedError("cones are not implemented for cubical complexes")
 
     def suspension(self, n=1):
         r"""
@@ -1430,7 +1430,7 @@ def suspension(self, n=1):
             sage: C1.suspension()
             Traceback (most recent call last):
             ...
-            NotImplementedError: Suspensions are not implemented for cubical complexes.
+            NotImplementedError: suspensions are not implemented for cubical complexes
         """
 #         if n<0:
 #             raise ValueError, "n must be non-negative."
@@ -1439,7 +1439,7 @@ def suspension(self, n=1):
 #         if n==1:
 #             return self.join(cubical_complexes.Sphere(0))
 #         return self.suspension().suspension(int(n-1))
-        raise NotImplementedError("Suspensions are not implemented for cubical complexes.")
+        raise NotImplementedError("suspensions are not implemented for cubical complexes")
 
     def product(self, other):
         r"""
@@ -1562,7 +1562,7 @@ def connected_sum(self, other):
         # C x 0 and C x 1, putting in its place (its boundary) x (0,1).
         if not (self.is_pure() and other.is_pure() and
                 self.dimension() == other.dimension()):
-            raise ValueError("Complexes are not pure of the same dimension.")
+            raise ValueError("complexes are not pure of the same dimension")
 
         self_facets = list(self.maximal_cells())
         other_facets = list(other.maximal_cells())
@@ -1939,6 +1939,7 @@ def Cube(self, n):
         if n == 0:
             return CubicalComplex([Cube([[0]])])
         else:
-            return CubicalComplex([Cube([[0,1]]*n)])
+            return CubicalComplex([Cube([[0, 1]] * n)])
+
 
 cubical_complexes = CubicalComplexExamples()

src/sage/topology/delta_complex.py

@@ -308,7 +308,7 @@ def store_bdry(simplex, faces):
                         new_data[dim] = []
                     for x in data:
                         if not isinstance(x, Simplex):
-                            raise TypeError("Each key in the data dictionary must be a simplex.")
+                            raise TypeError("each key in the data dictionary must be a simplex")
                         old_data_by_dim[x.dimension()].append(x)
                     old_delayed = {}
                     for dim in range(dimension, -1, -1):
@@ -338,7 +338,7 @@ def store_bdry(simplex, faces):
                                     current[bdry] = store_bdry(bdry, bdry.faces())
                                     new_data[dim].append(current[bdry])
                                 else:
-                                    raise ValueError("In the data dictionary, there is a value which is a simplex not already in the dictionary.  This is not allowed.")
+                                    raise ValueError("in the data dictionary, there is a value which is a simplex not already in the dictionary")
                             elif isinstance(bdry, (list, tuple)):
                                 # case 2
                                 # boundary is a list or tuple
@@ -367,8 +367,8 @@ def store_bdry(simplex, faces):
                     faces = new_data[d-1]
                     for j in range(d+1):
                         if not all(faces[s[j]][i] == faces[s[i]][j-1] for i in range(j)):
-                            msg = "Simplicial identity d_i d_j = d_{j-1} d_i fails"
-                            msg += " for j=%s, in dimension %s"%(j,d)
+                            msg = "simplicial identity d_i d_j = d_{j-1} d_i fails"
+                            msg += " for j=%s, in dimension %s" % (j, d)
                             raise ValueError(msg)
         # self._cells_dict: dictionary indexed by dimension d: for
         # each d, have list or tuple of simplices, and for each
@@ -557,7 +557,7 @@ def cells(self, subcomplex=None):
                     cells[d] = [None]*l   # get rid of all cells
                 return cells
             else:
-                raise ValueError("This is not a subcomplex of self.")
+                raise ValueError("this is not a subcomplex of self")
         else:
             subcomplex_cells = subcomplex._is_subcomplex_of[self]
             for d in range(0, max(subcomplex_cells.keys())+1):
@@ -919,7 +919,7 @@ def suspension(self, n=1):
             {0: 0, 1: 0, 2: 0, 3: Z}
         """
         if n<0:
-            raise ValueError("n must be non-negative.")
+            raise ValueError("n must be non-negative")
         if n==0:
             return self
         if n==1:
@@ -1156,7 +1156,7 @@ def connected_sum(self, other):
             Z x Z x C2
         """
         if not self.dimension() == other.dimension():
-            raise ValueError("Complexes are not of the same dimension.")
+            raise ValueError("complexes are not of the same dimension")
         dim = self.dimension()
         # Look at the last simplex in the list of top-dimensional
         # simplices for each complex.  If there are identifications on
@@ -1487,9 +1487,9 @@ def barycentric_subdivision(self):
             sage: K.barycentric_subdivision()
             Traceback (most recent call last):
             ...
-            NotImplementedError: Barycentric subdivisions are not implemented for Delta complexes.
+            NotImplementedError: barycentric subdivisions are not implemented for Delta complexes
         """
-        raise NotImplementedError("Barycentric subdivisions are not implemented for Delta complexes.")
+        raise NotImplementedError("barycentric subdivisions are not implemented for Delta complexes")
 
     def n_chains(self, n, base_ring=None, cochains=False):
         r"""
@@ -1666,7 +1666,8 @@ def Torus(self):
             sage: delta_complexes.Torus().homology(1)
             Z x Z
         """
-        return DeltaComplex(( ((),),  ((0,0), (0,0), (0,0)), ((1,2,0), (0, 2, 1))))
+        return DeltaComplex((((),), ((0, 0), (0, 0), (0, 0)),
+                             ((1, 2, 0), (0, 2, 1))))
 
     def RealProjectivePlane(self):
         r"""
@@ -1687,7 +1688,8 @@ def RealProjectivePlane(self):
             sage: P.cohomology(dim=2, base_ring=GF(2))
             Vector space of dimension 1 over Finite Field of size 2
         """
-        return DeltaComplex(( ((), ()),  ((1,0), (1,0), (0,0)), ((1,0,2), (0,1,2))))
+        return DeltaComplex((((), ()), ((1, 0), (1, 0), (0, 0)),
+                             ((1, 0, 2), (0, 1, 2))))
 
     def KleinBottle(self):
         r"""
@@ -1701,7 +1703,8 @@ def KleinBottle(self):
             sage: delta_complexes.KleinBottle()
             Delta complex with 1 vertex and 7 simplices
         """
-        return DeltaComplex(( ((),),  ((0,0), (0,0), (0,0)), ((1,2,0), (0, 1, 2))))
+        return DeltaComplex((((),), ((0, 0), (0, 0), (0, 0)),
+                             ((1, 2, 0), (0, 1, 2))))
 
     def Simplex(self, n):
         r"""
@@ -1770,8 +1773,9 @@ def SurfaceOfGenus(self, g, orientable=True):
         else:
             X = delta_complexes.RealProjectivePlane()
         S = X
-        for i in range(g-1):
+        for i in range(g - 1):
             S = S.connected_sum(X)
         return S
 
+
 delta_complexes = DeltaComplexExamples()

src/sage/topology/filtered_simplicial_complex.py

@@ -735,4 +735,3 @@ def _simplicial_(self):
             Simplicial complex with vertex set (0, 1, 2, 3) and facets {(0, 1, 2), (0, 2, 3)}
         """
         return SimplicialComplex(self._filtration_dict)
-

src/sage/topology/simplicial_complex.py

@@ -119,17 +119,17 @@
     sage: hash(S)
     Traceback (most recent call last):
     ...
-    ValueError: This simplicial complex must be immutable. Call set_immutable().
+    ValueError: this simplicial complex must be immutable; call set_immutable()
     sage: S = SimplicialComplex([[1,4], [2,4]])
     sage: S.set_immutable()
     sage: S.add_face([1,3])
     Traceback (most recent call last):
     ...
-    ValueError: This simplicial complex is not mutable
+    ValueError: this simplicial complex is not mutable
     sage: S.remove_face([1,3])
     Traceback (most recent call last):
     ...
-    ValueError: This simplicial complex is not mutable
+    ValueError: this simplicial complex is not mutable
     sage: hash(S) == hash(S)
     True
 
@@ -1134,7 +1134,7 @@ def __hash__(self):
             sage: hash(S)
             Traceback (most recent call last):
             ...
-            ValueError: This simplicial complex must be immutable. Call set_immutable().
+            ValueError: this simplicial complex must be immutable; call set_immutable()
             sage: S.set_immutable()
             sage: hash(S) == hash(S)
             True
@@ -1145,7 +1145,7 @@ def __hash__(self):
             True
         """
         if not self._is_immutable:
-            raise ValueError("This simplicial complex must be immutable. Call set_immutable().")
+            raise ValueError("this simplicial complex must be immutable; call set_immutable()")
         return hash(frozenset(self._facets))
 
     def __eq__(self, right):
@@ -1903,7 +1903,7 @@ def suspension(self, n=1, is_mutable=True):
             (0, 1, 2, 3, 4, 5, 6, 7)
         """
         if n < 0:
-            raise ValueError("n must be non-negative.")
+            raise ValueError("n must be non-negative")
         if n == 0:
             return self
         if n == 1:
@@ -2555,7 +2555,7 @@ def add_face(self, face):
             sage: X.add_face([0,1])
         """
         if self._is_immutable:
-            raise ValueError("This simplicial complex is not mutable")
+            raise ValueError("this simplicial complex is not mutable")
 
         vertex_to_index = self._translation_to_numeric()
 
@@ -2673,7 +2673,7 @@ def remove_face(self, face, check=False):
             Simplicial complex with vertex set (1, 2, 3) and facets {(3,), (1, 2)}
         """
         if self._is_immutable:
-            raise ValueError("This simplicial complex is not mutable")
+            raise ValueError("this simplicial complex is not mutable")
 
         getindex = self._translation_to_numeric().__getitem__
         simplex = Simplex(sorted(face, key=getindex))
@@ -3165,7 +3165,6 @@ def is_shellable(self, certificate=False):
                     it.append(iter(set(facets)))
                 continue
 
-
             # The shelling condition is precisely that intersection is
             #    a pure complex of one dimension less and stop if this fails
             common = set(F).intersection(set(cur_complex.vertices()))

src/sage/topology/simplicial_complex_examples.py

@@ -390,8 +390,10 @@ def RealProjectivePlane():
                               [2, 3, 5], [2, 4, 5]],
                               name='Minimal triangulation of the real projective plane')
 
+
 ProjectivePlane = RealProjectivePlane
 
+
 def KleinBottle():
     """
     A minimal triangulation of the Klein bottle, as presented for example
@@ -436,7 +438,7 @@ def SurfaceOfGenus(g, orientable=True):
     """
     if g == 0:
         if not orientable:
-            raise ValueError("No non-orientable surface of genus zero.")
+            raise ValueError("no non-orientable surface of genus zero")
         else:
             return Sphere(2)
     if orientable:
@@ -490,7 +492,7 @@ def MooreSpace(q):
         Triangulation of the mod 8 Moore space
     """
     if q <= 1:
-        raise ValueError("The mod q Moore space is only defined if q is at least 2")
+        raise ValueError("the mod q Moore space is only defined if q is at least 2")
     if q == 2:
         return RealProjectivePlane()
     facets = []

src/sage/topology/simplicial_complex_homset.py

@@ -41,7 +41,7 @@
 
 """
 
-#*****************************************************************************
+# ****************************************************************************
 # Copyright (C) 2009 D. Benjamin Antieau <[email protected]>
 #
 #  Distributed under the terms of the GNU General Public License (GPL)
@@ -53,9 +53,9 @@
 #  See the GNU General Public License for more details; the full text
 #  is available at:
 #
-#                  http://www.gnu.org/licenses/
+#                  https://www.gnu.org/licenses/
 #
-#*****************************************************************************
+# ****************************************************************************
 
 import sage.categories.homset
 from .simplicial_complex_morphism import SimplicialComplexMorphism
@@ -193,4 +193,3 @@ def an_element(self):
                 raise TypeError("there are no morphisms from a non-empty simplicial complex to an empty simplicial complex")
         f = {x: i for x in X_vertices}
         return SimplicialComplexMorphism(f, self._domain, self._codomain)
-