Trac #34647: some details in permutation groups

mostly a few pep8 changes

URL: https://trac.sagemath.org/34647
Reported by: chapoton
Ticket author(s): Frédéric Chapoton
Reviewer(s): Travis Scrimshaw

src/sage/groups/perm_gps/all.py

@@ -1,17 +1,20 @@
 from .permgroup_named import (SymmetricGroup, AlternatingGroup,
-                       DihedralGroup, SplitMetacyclicGroup, SemidihedralGroup, CyclicPermutationGroup,
-                       DiCyclicGroup, TransitiveGroup, PGL, PSL, PSp,PSU,PGU,
-                       MathieuGroup, KleinFourGroup, QuaternionGroup,
-                       PrimitiveGroup, PrimitiveGroups,
-                       SuzukiGroup, TransitiveGroups, GeneralDihedralGroup)
+                              DihedralGroup, SplitMetacyclicGroup,
+                              SemidihedralGroup, CyclicPermutationGroup,
+                              DiCyclicGroup, TransitiveGroup,
+                              PGL, PSL, PSp, PSU, PGU,
+                              MathieuGroup, KleinFourGroup, QuaternionGroup,
+                              PrimitiveGroup, PrimitiveGroups,
+                              SuzukiGroup, TransitiveGroups,
+                              GeneralDihedralGroup)
 
-from .permgroup import  PermutationGroup, PermutationGroup_generic, PermutationGroup_subgroup, direct_product_permgroups
+from .permgroup import PermutationGroup, PermutationGroup_generic, PermutationGroup_subgroup, direct_product_permgroups
 
 from .constructor import PermutationGroupElement
 
 from .permgroup_morphism import (PermutationGroupMorphism as PermutationGroupMap,
-                                PermutationGroupMorphism_im_gens,
-                                PermutationGroupMorphism_id)
+                                 PermutationGroupMorphism_im_gens,
+                                 PermutationGroupMorphism_id)
 PermutationGroupMorphism = PermutationGroupMorphism_im_gens
 
 from .cubegroup import CubeGroup, RubiksCube

src/sage/groups/perm_gps/constructor.py

@@ -7,7 +7,7 @@
 objects have a more group theoretic flavor than the more combinatorial
 :class:`~sage.combinat.permutation.Permutation`.
 """
-#*****************************************************************************
+# ****************************************************************************
 #       Copyright (C) 2006 William Stein <wstein@gmail.com>
 #       Copyright (C) 2006 David Joyner
 #       Copyright (C) 2019 Vincent Delecroix <20100.delecroix@gmail.com>
@@ -16,16 +16,17 @@
 # it under the terms of the GNU General Public License 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 . import permgroup_element
 from sage.misc.sage_eval import sage_eval
 from sage.misc.lazy_import import lazy_import
 from sage.interfaces.gap import GapElement
-lazy_import('sage.combinat.permutation', ['Permutation', 'from_cycles'])
 from sage.libs.pari.all import pari_gen
 from sage.libs.gap.element import GapElement_Permutation
+lazy_import('sage.combinat.permutation', ['Permutation', 'from_cycles'])
+
 
 def PermutationGroupElement(g, parent=None, check=True):
     r"""
@@ -118,6 +119,7 @@ def PermutationGroupElement(g, parent=None, check=True):
 
     return parent.element_class(g, parent, check)
 
+
 def string_to_tuples(g):
     """
     EXAMPLES::
@@ -136,10 +138,11 @@ def string_to_tuples(g):
         raise ValueError("g (= %s) must be a string" % g)
     elif g == '()':
         return []
-    g = g.replace('\n','').replace(' ', '').replace(')(', '),(').replace(')', ',)')
+    g = g.replace('\n', '').replace(' ', '').replace(')(', '),(').replace(')', ',)')
     g = '[' + g + ']'
     return sage_eval(g, preparse=False)
 
+
 def standardize_generator(g, convert_dict=None, as_cycles=False):
     r"""
     Standardize the input for permutation group elements to a list
@@ -258,6 +261,6 @@ def standardize_generator(g, convert_dict=None, as_cycles=False):
     if convert_dict is not None and needs_conversion:
         g = [tuple([convert_dict[x] for x in cycle]) for cycle in g]
     if not as_cycles:
-        degree = max([1] + [max(cycle+(1,)) for cycle in g])
+        degree = max([1] + [max(cycle + (1,)) for cycle in g])
         g = from_cycles(degree, g)
     return g

src/sage/groups/perm_gps/partn_ref/refinement_graphs.pyx

@@ -7,10 +7,9 @@ EXAMPLES::
 
 REFERENCE:
 
-- [1] McKay, Brendan D. Practical Graph Isomorphism. Congressus Numerantium,
+- [1] McKay, Brendan D. *Practical Graph Isomorphism*. Congressus Numerantium,
   Vol. 30 (1981), pp. 45-87.
 """
-
 # ****************************************************************************
 #       Copyright (C) 2006 - 2011 Robert L. Miller <rlmillster@gmail.com>
 #
@@ -643,9 +642,8 @@ cdef int compare_graphs(int *gamma_1, int *gamma_2, void *S1, void *S2, int degr
     r"""
     Compare gamma_1(S1) and gamma_2(S2).
 
-    Return return -1 if gamma_1(S1) < gamma_2(S2), 0 if gamma_1(S1) ==
-    gamma_2(S2), 1 if gamma_1(S1) > gamma_2(S2).  (Just like the python
-    \code{cmp}) function.
+    Return -1 if gamma_1(S1) < gamma_2(S2), 0 if gamma_1(S1) ==
+    gamma_2(S2), 1 if gamma_1(S1) > gamma_2(S2).
 
     INPUT:
 

src/sage/groups/perm_gps/permgroup_morphism.py

@@ -30,24 +30,26 @@
     Cyclic group of order 4 as a permutation group
 """
 
-#*****************************************************************************
+# ****************************************************************************
 #       Copyright (C) 2006 David Joyner and William Stein <wstein@gmail.com>
 #
 #  Distributed under the terms of the GNU General Public License (GPL)
-#                  http://www.gnu.org/licenses/
-#*****************************************************************************
+#                  https://www.gnu.org/licenses/
+# ****************************************************************************
 
 from sage.categories.morphism import Morphism
 from sage.groups.perm_gps.permgroup import PermutationGroup, PermutationGroup_generic
 
+
 class PermutationGroupMorphism(Morphism):
     """
     A set-theoretic map between PermutationGroups.
     """
     def _repr_type(self):
         """
-        Returns the type of this morphism.  This is used for printing
-        the morphism.
+        Return the type of this morphism.
+
+        This is used for printing the morphism.
 
         EXAMPLES::
 
@@ -60,7 +62,7 @@ def _repr_type(self):
 
     def kernel(self):
         """
-        Returns the kernel of this homomorphism as a permutation group.
+        Return the kernel of this homomorphism as a permutation group.
 
         EXAMPLES::
 
@@ -134,7 +136,7 @@ def image(self, J):
     def __call__(self, g):
         """
         Some python code for wrapping GAP's Images function but only for
-        permutation groups. Returns an error if g is not in G.
+        permutation groups. This returns an error if g is not in G.
 
         EXAMPLES::
 
@@ -148,9 +150,11 @@ def __call__(self, g):
         """
         return self.image(g)
 
+
 class PermutationGroupMorphism_id(PermutationGroupMorphism):
     pass
 
+
 class PermutationGroupMorphism_from_gap(PermutationGroupMorphism):
     def __init__(self, G, H, gap_hom):
         """
@@ -201,7 +205,7 @@ def _repr_defn(self):
 
     def _gap_(self, gap=None):
         """
-        Returns a GAP version of this morphism.
+        Return a GAP version of this morphism.
 
         EXAMPLES::
 
@@ -217,7 +221,7 @@ def _gap_(self, gap=None):
     def __call__(self, g):
         """
         Some python code for wrapping GAP's Images function but only for
-        permutation groups. Returns an error if g is not in G.
+        permutation groups. This returns an error if g is not in G.
 
         EXAMPLES::
 
@@ -236,7 +240,7 @@ def __init__(self, G, H, gens=None):
         """
         Some python code for wrapping GAP's GroupHomomorphismByImages
         function but only for permutation groups. Can be expensive if G is
-        large. Returns "fail" if gens does not generate self or if the map
+        large. This returns "fail" if gens does not generate self or if the map
         does not extend to a group homomorphism, self - other.
 
         EXAMPLES::
@@ -270,8 +274,9 @@ def __init__(self, G, H, gens=None):
 
     def _repr_defn(self):
         """
-        Returns the definition of this morphism.  This is used when
-        printing the morphism.
+        Return the definition of this morphism.
+
+        This is used when printing the morphism.
 
         EXAMPLES::
 
@@ -281,11 +286,11 @@ def _repr_defn(self):
             sage: phi._repr_defn()
             '[(1,2,3,4)] -> [(1,2,3,4)]'
         """
-        return "%s -> %s"%(list(self.domain().gens()), self._images)
+        return "%s -> %s" % (list(self.domain().gens()), self._images)
 
     def _gap_(self):
         """
-        Returns a GAP representation of this morphism.
+        Return a GAP representation of this morphism.
 
         EXAMPLES::
 
@@ -298,9 +303,10 @@ def _gap_(self):
         """
         return self.domain()._gap_().GroupHomomorphismByImages(self.codomain(), self.domain().gens(), self._images)
 
-def is_PermutationGroupMorphism(f):
+
+def is_PermutationGroupMorphism(f) -> bool:
     """
-    Returns True if the argument ``f`` is a PermutationGroupMorphism.
+    Return True if the argument ``f`` is a PermutationGroupMorphism.
 
     EXAMPLES::
 

src/sage/groups/perm_gps/permutation_groups_catalog.py

@@ -26,6 +26,6 @@
 from .permgroup_named import JankoGroup as Janko
 from .permgroup_named import SuzukiSporadicGroup as SuzukiSporadic
 from .permgroup_named import SuzukiGroup as Suzuki
-from .permgroup_named import (PGL, PSL, PSp,PSU,PGU,)
+from .permgroup_named import (PGL, PSL, PSp, PSU, PGU)
 from .permgroup_named import TransitiveGroup as Transitive
 from .cubegroup import CubeGroup as RubiksCube

src/sage/groups/perm_gps/symgp_conjugacy_class.py

@@ -48,7 +48,7 @@ def _repr_(self):
             Conjugacy class of cycle type [4] in
              Symmetric group of order 4! as a permutation group
         """
-        return "Conjugacy class of cycle type %s in %s"%(self._part, self._parent)
+        return "Conjugacy class of cycle type %s in %s" % (self._part, self._parent)
 
     def __eq__(self, other):
         r"""
@@ -167,9 +167,10 @@ def set(self):
         """
         if not self._set:
             self._set = Set(self._parent.element_class(x, self._parent, check=False)
-                            for x in conjugacy_class_iterator(self._part, self._domain) )
+                            for x in conjugacy_class_iterator(self._part, self._domain))
         return self._set
 
+
 class PermutationsConjugacyClass(SymmetricGroupConjugacyClassMixin, ConjugacyClass):
     """
     A conjugacy class of the permutations of `n`.
@@ -197,7 +198,7 @@ def __init__(self, P, part):
             part = elt.cycle_type()
         else:
             elt = P.element_in_conjugacy_classes(part)
-        SymmetricGroupConjugacyClassMixin.__init__(self, range(1, P.n+1), part)
+        SymmetricGroupConjugacyClassMixin.__init__(self, range(1, P.n + 1), part)
         ConjugacyClass.__init__(self, P, elt)
 
     def __iter__(self):
@@ -241,11 +242,12 @@ def set(self):
         """
         if not self._set:
             self._set = Set(from_cycles(self._parent.n, x, self._parent)
-                            for x in conjugacy_class_iterator(self._part, self._domain) )
+                            for x in conjugacy_class_iterator(self._part, self._domain))
         return self._set
 
+
 #####################################################################
-## Helper functions
+# Helper functions
 
 def default_representative(part, G):
     r"""
@@ -284,7 +286,7 @@ def default_representative(part, G):
     total = 0
     cycles = []
     for p in part:
-        cycles.append(tuple(D[total:total+p]))
+        cycles.append(tuple(D[total:total + p]))
         total += p
     return G.element_class(cycles, G, check=False)