trac #34075: fix merge conflict with 9.7.beta8

src/sage/graphs/bipartite_graph.py

@@ -434,7 +434,7 @@ def __init__(self, data=None, partition=None, check=True, *args, **kwds):
 
                     if check:
                         if (any(left.intersection(self.neighbor_iterator(a)) for a in left) or
-                            any(right.intersection(self.neighbor_iterator(a)) for a in right)):
+                                any(right.intersection(self.neighbor_iterator(a)) for a in right)):
                             raise TypeError("input graph is not bipartite with "
                                             "respect to the given partition")
                     else:
@@ -453,9 +453,8 @@ def __init__(self, data=None, partition=None, check=True, *args, **kwds):
         elif is_Matrix(data):
             # sanity check for mutually exclusive keywords
             if kwds.get("multiedges", False) and kwds.get("weighted", False):
-                raise TypeError(
-                    "weighted multi-edge bipartite graphs from reduced "
-                    "adjacency matrix not supported")
+                raise TypeError("weighted multi-edge bipartite graphs from "
+                                "reduced adjacency matrix not supported")
             Graph.__init__(self, *args, **kwds)
             ncols = data.ncols()
             nrows = data.nrows()
@@ -509,13 +508,12 @@ def __init__(self, data=None, partition=None, check=True, *args, **kwds):
                         elif data.node_type[v] == "Top":
                             self.right.add(v)
                         else:
-                            raise TypeError(
-                                "NetworkX node_type defies bipartite "
-                                "assumption (is not 'Top' or 'Bottom')")
+                            raise TypeError("NetworkX node_type defies bipartite "
+                                            "assumption (is not 'Top' or 'Bottom')")
             elif partition:
                 if check:
                     if (any(left.intersection(self.neighbor_iterator(a)) for a in left) or
-                        any(right.intersection(self.neighbor_iterator(a)) for a in right)):
+                            any(right.intersection(self.neighbor_iterator(a)) for a in right)):
                         raise TypeError("input graph is not bipartite with "
                                         "respect to the given partition")
                 else:
@@ -672,7 +670,7 @@ def add_vertex(self, name=None, left=False, right=False):
         # do nothing if we already have this vertex (idempotent)
         if name is not None and name in self:
             if ((left and name in self.left) or
-                (right and name in self.right)):
+                    (right and name in self.right)):
                 return
             else:
                 raise RuntimeError("cannot add duplicate vertex to other partition")
@@ -772,10 +770,9 @@ def add_vertices(self, vertices, left=False, right=False):
         # check that we're not trying to add vertices to the wrong sets
         # or that a vertex is to be placed in both
         if ((new_left & self.right) or
-            (new_right & self.left) or
-            (new_right & new_left)):
-            raise RuntimeError(
-                "cannot add duplicate vertex to other partition")
+                (new_right & self.left) or
+                (new_right & new_left)):
+            raise RuntimeError("cannot add duplicate vertex to other partition")
 
         # add vertices
         Graph.add_vertices(self, vertices)
@@ -2400,7 +2397,11 @@ class by some canonization function `c`. If `G` and `H` are graphs,
         """
 
         if certificate:
-            C, cert = GenericGraph.canonical_label(self, partition=partition, certificate=certificate, edge_labels=edge_labels, algorithm=algorithm, return_graph=return_graph)
+            C, cert = GenericGraph.canonical_label(self, partition=partition,
+                                                   certificate=certificate,
+                                                   edge_labels=edge_labels,
+                                                   algorithm=algorithm,
+                                                   return_graph=return_graph)
 
         else:
             from sage.groups.perm_gps.partn_ref.refinement_graphs import search_tree

src/sage/graphs/digraph_generators.py

@@ -687,14 +687,14 @@ def nauty_directg(self, graphs, options="", debug=False):
             if out:
                 print(out)
 
-        for l in out.split('\n'):
+        for line in out.split('\n'):
             # directg return graphs in the digraph6 format.
             # digraph6 is very similar with the dig6 format used in sage :
             # digraph6_string = '&' +  dig6_string
             # digraph6 specifications:
             # http://users.cecs.anu.edu.au/~bdm/data/formats.txt
-            if l and l[0] == '&':
-                yield DiGraph(l[1:], format='dig6')
+            if line and line[0] == '&':
+                yield DiGraph(line[1:], format='dig6')
 
     def Complete(self, n, loops=False):
         r"""
@@ -1095,12 +1095,19 @@ def Kautz(self, k, D, vertices='strings'):
 
             sage: K = digraphs.Kautz([1,'a','B'], 2)
             sage: K.edges(sort=True)
-            [('1B', 'B1', '1'), ('1B', 'Ba', 'a'), ('1a', 'a1', '1'), ('1a', 'aB', 'B'), ('B1', '1B', 'B'), ('B1', '1a', 'a'), ('Ba', 'a1', '1'), ('Ba', 'aB', 'B'), ('a1', '1B', 'B'), ('a1', '1a', 'a'), ('aB', 'B1', '1'), ('aB', 'Ba', 'a')]
+            [('1B', 'B1', '1'), ('1B', 'Ba', 'a'), ('1a', 'a1', '1'),
+             ('1a', 'aB', 'B'), ('B1', '1B', 'B'), ('B1', '1a', 'a'),
+             ('Ba', 'a1', '1'), ('Ba', 'aB', 'B'), ('a1', '1B', 'B'),
+             ('a1', '1a', 'a'), ('aB', 'B1', '1'), ('aB', 'Ba', 'a')]
 
             sage: K = digraphs.Kautz([1,'aA','BB'], 2)
             sage: K.edges(sort=True)
-            [('1,BB', 'BB,1', '1'), ('1,BB', 'BB,aA', 'aA'), ('1,aA', 'aA,1', '1'), ('1,aA', 'aA,BB', 'BB'), ('BB,1', '1,BB', 'BB'), ('BB,1', '1,aA', 'aA'), ('BB,aA', 'aA,1', '1'), ('BB,aA', 'aA,BB', 'BB'), ('aA,1', '1,BB', 'BB'), ('aA,1', '1,aA', 'aA'), ('aA,BB', 'BB,1', '1'), ('aA,BB', 'BB,aA', 'aA')]
-
+            [('1,BB', 'BB,1', '1'), ('1,BB', 'BB,aA', 'aA'),
+             ('1,aA', 'aA,1', '1'), ('1,aA', 'aA,BB', 'BB'),
+             ('BB,1', '1,BB', 'BB'), ('BB,1', '1,aA', 'aA'),
+             ('BB,aA', 'aA,1', '1'), ('BB,aA', 'aA,BB', 'BB'),
+             ('aA,1', '1,BB', 'BB'), ('aA,1', '1,aA', 'aA'),
+             ('aA,BB', 'BB,1', '1'), ('aA,BB', 'BB,aA', 'aA')]
 
         TESTS:
 

src/sage/graphs/domination.py

@@ -66,6 +66,7 @@
 from copy import copy
 from sage.rings.integer import Integer
 
+
 def is_dominating(G, dom, focus=None):
     r"""
     Check whether ``dom`` is a dominating set of ``G``.
@@ -101,6 +102,7 @@ def is_dominating(G, dom, focus=None):
 
     return not to_dom
 
+
 def is_redundant(G, dom, focus=None):
     r"""
     Check whether ``dom`` has redundant vertices.
@@ -166,6 +168,7 @@ def is_redundant(G, dom, focus=None):
     # with_private != set(dom)
     return len(with_private) != len(dom)
 
+
 def private_neighbors(G, vertex, dom):
     r"""
     Return the private neighbors of a vertex with respect to other vertices.
@@ -361,6 +364,7 @@ def neighbors_iter(x):
     dom = [v for v in g if b[v]]
     return Integer(len(dom)) if value_only else dom
 
+
 # ==============================================================================
 # Enumeration of minimal dominating set as described in [BDHPR2019]_
 # ==============================================================================
@@ -785,6 +789,7 @@ def tree_search(H, plng, dom, i):
     for dom in tree_search(G, peeling, set(), 0):
         yield {int_to_vertex[v] for v in dom}
 
+
 # ==============================================================================
 # Greedy heuristic for dominating set
 # ==============================================================================

src/sage/graphs/dot2tex_utils.py

@@ -1,17 +1,18 @@
 r"""
 This file contains some utility functions for the interface with dot2tex
 """
-#*****************************************************************************
+# ****************************************************************************
 #      Copyright (C) 2010   Nicolas M. Thiery <nicolas.thiery at u-psud.fr>
 #
 #  Distributed under the terms of the GNU General Public License (GPL)
-#                  http://www.gnu.org/licenses/
-#*****************************************************************************
+#                  https://www.gnu.org/licenses/
+# ****************************************************************************
 
 import re
 from sage.misc.latex import latex
 from sage.misc.cachefunc import cached_function
 
+
 @cached_function
 def have_dot2tex():
     """
@@ -28,7 +29,7 @@ def have_dot2tex():
     try:
         import dot2tex
         # Test for this required feature from dot2tex 2.8.7
-        return dot2tex.dot2tex("graph {}", format = "positions") == {}
+        return dot2tex.dot2tex("graph {}", format="positions") == {}
     except (Exception, SystemExit):
         return False
 
@@ -60,11 +61,12 @@ def assert_have_dot2tex():
         import dot2tex
     except ImportError:
         print(import_error_string)
-        raise # re-raise current exception
+        raise  # re-raise current exception
     else:
-        if dot2tex.dot2tex("graph {}", format = "positions") != {}:
+        if dot2tex.dot2tex("graph {}", format="positions") != {}:
             raise RuntimeError(check_error_string)
 
+
 def quoted_latex(x):
     """
     Strips the latex representation of ``x`` to make it suitable for a
@@ -75,7 +77,8 @@ def quoted_latex(x):
         sage: sage.graphs.dot2tex_utils.quoted_latex(matrix([[1,1],[0,1],[0,0]]))
         '\\left(\\begin{array}{rr}1 & 1 \\\\0 & 1 \\\\0 & 0\\end{array}\\right)'
     """
-    return re.sub("\"|\r|(%[^\n]*)?\n","", latex(x))
+    return re.sub("\"|\r|(%[^\n]*)?\n", "", latex(x))
+
 
 
 def quoted_str(x):
@@ -94,4 +97,4 @@ def quoted_str(x):
         [0 1]\n\
         [0 0]
     """
-    return re.sub("\n",r"\\n\\"+"\n", re.sub("\"|\r|}|{","", str(x)))
+    return re.sub("\n", r"\\n\\"+"\n", re.sub("\"|\r|}|{", "", str(x)))