.

wcfs/internal/xbtree.py

@@ -250,8 +250,11 @@ def Restructure(ztree, newStructure):
             rn.node.Z = None
 
         def D(a, b):
-            return abs(a.range.klo - b.range.klo) + \
-                   abs(a.range.khi - b.range.khi)
+            def d(x,y):
+                if x == y: return 0     # prevents inf-inf -> nan
+                return abs(x-y)
+            return d(a.range.klo, b.range.klo) + \
+                   d(a.range.khi, b.range.khi)
 
         # prepare cost matrix
         C = np.zeros((len(RNv), len(RZv)))