PEP8 fixes to distance_regular.

1 files changed, 29 insertions, 30 deletions

diff --git a/networkx/algorithms/distance_regular.py b/networkx/algorithms/distance_regular.py
index c17744d7..e057228e 100644
--- a/networkx/algorithms/distance_regular.py
+++ b/networkx/algorithms/distance_regular.py
@@ -1,4 +1,4 @@
-#    Copyright (C) 2011 by 
+#    Copyright (C) 2011 by
 #    Dheeraj M R <dheerajrav@gmail.com>
 #    Aric Hagberg <aric.hagberg@gmail.com>
 #    All rights reserved.
@@ -8,15 +8,14 @@
 Distance-regular graphs
 =======================
 """
-from itertools import product
-
 import networkx as nx
 from networkx.utils import not_implemented_for
 
 __author__ = """\n""".join(['Dheeraj M R <dheerajrav@gmail.com>',
                             'Aric Hagberg <aric.hagberg@gmail.com>'])
 
-__all__ = ['is_distance_regular','intersection_array','global_parameters']
+__all__ = ['is_distance_regular', 'intersection_array', 'global_parameters']
+
 
 def is_distance_regular(G):
     """Returns True if the graph is distance regular, False otherwise.
@@ -41,7 +40,7 @@ def is_distance_regular(G):
     >>> G=nx.hypercube_graph(6)
     >>> nx.is_distance_regular(G)
     True
-    
+
     See Also
     --------
     intersection_array, global_parameters
@@ -52,18 +51,19 @@ def is_distance_regular(G):
 
     References
     ----------
-    .. [1] Brouwer, A. E.; Cohen, A. M.; and Neumaier, A. 
+    .. [1] Brouwer, A. E.; Cohen, A. M.; and Neumaier, A.
         Distance-Regular Graphs. New York: Springer-Verlag, 1989.
-    .. [2] Weisstein, Eric W. "Distance-Regular Graph." 
+    .. [2] Weisstein, Eric W. "Distance-Regular Graph."
         http://mathworld.wolfram.com/Distance-RegularGraph.html
 
     """
     try:
-        a=intersection_array(G)
+        intersection_array(G)
         return True
     except nx.NetworkXError:
         return False
 
+
 def global_parameters(b, c):
     """Return global parameters for a given intersection array.
 
@@ -71,7 +71,7 @@ def global_parameters(b, c):
     such that for any 2 vertices x,y in G at a distance i=d(x,y), there
     are exactly c_i neighbors of y at a distance of i-1 from x and b_i
     neighbors of y at a distance of i+1 from x.
-    
+
     Thus, a distance regular graph has the global parameters,
     [[c_0,a_0,b_0],[c_1,a_1,b_1],......,[c_d,a_d,b_d]] for the
     intersection array  [b_0,b_1,.....b_{d-1};c_1,c_2,.....c_d]
@@ -97,13 +97,13 @@ def global_parameters(b, c):
 
     References
     ----------
-    .. [1] Weisstein, Eric W. "Global Parameters." 
-       From MathWorld--A Wolfram Web Resource. 
-       http://mathworld.wolfram.com/GlobalParameters.html 
+    .. [1] Weisstein, Eric W. "Global Parameters."
+       From MathWorld--A Wolfram Web Resource.
+       http://mathworld.wolfram.com/GlobalParameters.html
 
     See Also
     --------
-    intersection_array 
+    intersection_array
     """
     return ((y, b[0] - x - y, x) for x, y in zip(b + [0], [0] + c))
 
@@ -117,7 +117,7 @@ def intersection_array(G):
     are exactly c_i neighbors of y at a distance of i-1 from x and b_i
     neighbors of y at a distance of i+1 from x.
 
-    A distance regular graph'sintersection array is given by, 
+    A distance regular graph's intersection array is given by,
     [b_0,b_1,.....b_{d-1};c_1,c_2,.....c_d]
 
     Parameters
@@ -126,7 +126,7 @@ def intersection_array(G):
 
     Returns
     -------
-    b,c: tuple of lists 
+    b,c: tuple of lists
 
     Examples
     --------
@@ -136,10 +136,9 @@ def intersection_array(G):
 
     References
     ----------
-    .. [1] Weisstein, Eric W. "Intersection Array." 
-       From MathWorld--A Wolfram Web Resource. 
+    .. [1] Weisstein, Eric W. "Intersection Array."
+       From MathWorld--A Wolfram Web Resource.
        http://mathworld.wolfram.com/IntersectionArray.html
-    
 
     See Also
     --------
@@ -147,15 +146,15 @@ def intersection_array(G):
     """
     # test for regular graph (all degrees must be equal)
     degree = G.degree_iter()
-    (_,k) = next(degree)
-    for _,knext in degree:
+    (_, k) = next(degree)
+    for _, knext in degree:
         if knext != k:
             raise nx.NetworkXError('Graph is not distance regular.')
         k = knext
-    path_length = nx.all_pairs_shortest_path_length(G)  
+    path_length = nx.all_pairs_shortest_path_length(G)
     diameter = max([max(path_length[n].values()) for n in path_length])
-    bint = {} # 'b' intersection array
-    cint = {} # 'c' intersection array
+    bint = {}  # 'b' intersection array
+    cint = {}  # 'c' intersection array
     for u in G:
         for v in G:
             try:
@@ -163,13 +162,13 @@ def intersection_array(G):
             except KeyError:  # graph must be connected
                 raise nx.NetworkXError('Graph is not distance regular.')
             # number of neighbors of v at a distance of i-1 from u
-            c = len([n for n in G[v] if path_length[n][u]==i-1])
+            c = len([n for n in G[v] if path_length[n][u] == i - 1])
             # number of neighbors of v at a distance of i+1 from u
-            b = len([n for n in G[v] if path_length[n][u]==i+1])
+            b = len([n for n in G[v] if path_length[n][u] == i + 1])
             # b,c are independent of u and v
-            if cint.get(i,c) != c or bint.get(i,b) != b:
+            if cint.get(i, c) != c or bint.get(i, b) != b:
                 raise nx.NetworkXError('Graph is not distance regular')
-            bint[i] = b 
-            cint[i] = c 
-    return ([bint.get(i,0) for i in range(diameter)],
-            [cint.get(i+1,0) for i in range(diameter)])
+            bint[i] = b
+            cint[i] = c
+    return ([bint.get(j, 0) for j in range(diameter)],
+            [cint.get(j + 1, 0) for j in range(diameter)])