explicitly normalising undirected edges

MaineKuehn · Jul 29, 2018 · 2c440f4 · 2c440f4
1 parent b267e75
commit 2c440f4
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Showing 2 changed files with 3 additions and 2 deletions.
diff --git a/graphi/types/bounded.py b/graphi/types/bounded.py
@@ -41,7 +41,7 @@ def _ensure_bounds(self):
         except TypeError as err:
             raise ValueError('cannot bound %r to %r: %s' % (value, self.value_bound, err))
         if self.undirected:
-            blacklist = {{tail, head} for tail, head in blacklist}
+            blacklist = {(tail, head) if hash(head) > hash(tail) else (head, tail) for tail, head in blacklist}
         for tail, head in blacklist:
             del self._graph[tail:head]
 

diff --git a/graphi/types/undirected.py b/graphi/types/undirected.py
@@ -19,7 +19,8 @@ def __init__(self, start, stop, step=None):
         # start and stop may be unsortable,
         # but the interface guarantees that they
         # are hashable
-        start, stop = {start, stop}
+        if hash(start) > hash(stop):
+            start, stop = stop, start
         super(UndirectedEdge, self).__init__(start, stop, step)
 
     def __eq__(self, other):