--- dbCellMapping.cc.o	2018-05-11 11:46:36.416064830 -0400
+++ dbCellMapping.cc	2018-05-11 11:47:02.921846210 -0400
@@ -75,6 +75,12 @@
 	return *this;
   }
 
+  SortedCellIndexIterator &operator--() 
+  {
+    --m_n;
+	return *this;
+  }
+
   SortedCellIndexIterator &operator+=(size_t n) 
   {
     m_n += n;