diff -r 9632ea8be6ca -r e9ed28955421 src/hugo/graph_wrapper.h
--- a/src/hugo/graph_wrapper.h	Fri May 07 08:18:30 2004 +0000
+++ b/src/hugo/graph_wrapper.h	Fri May 07 08:48:11 2004 +0000
@@ -806,6 +806,13 @@
       return ((!e.backward) ? this->graph->bNode(e.in) : 
 	      this->graph->bNode(e.out)); }
 
+    /// Gives back the opposite edge.
+    Edge opposite(const Edge& e) const { 
+      Edge f=e;
+      f.backward=!f.backward;
+      return f;
+    }
+
 //    int nodeNum() const { return graph->nodeNum(); }
     //FIXME
     void edgeNum() const { }