diff -r 3a98a1aa5a8f -r ef09eee53b09 src/hugo/array_map.h
--- a/src/hugo/array_map.h	Wed Sep 22 07:32:57 2004 +0000
+++ b/src/hugo/array_map.h	Wed Sep 22 08:04:31 2004 +0000
@@ -29,6 +29,8 @@
 
   template <typename MapRegistry, typename Value> 
   class ArrayMap : public MapRegistry::MapBase {
+
+    template <typename MR, typename V> friend class ArrayMap;
 		
   public:
 		
@@ -63,10 +65,6 @@
     typedef std::allocator<Value> Allocator;
 
 	
-    /** Default constructor for the map.
-     */
-    ArrayMap() : capacity(0), values(0) {}
-			
     /** Graph and Registry initialized map constructor.
      */
     ArrayMap(const Graph& g, MapRegistry& r) : MapBase(g, r) {
@@ -118,18 +116,19 @@
      */
     ArrayMap& operator=(const ArrayMap& copy) {
       if (&copy == this) return *this;
+      
+      if (MapBase::getGraph() != copy.getGraph()) {
+	if (capacity != 0) {
+	  MapBase::destroy();
+	  allocator.deallocate(values, capacity);
+	}
 
-      if (capacity != 0) {
-	MapBase::destroy();
-	allocator.deallocate(values, capacity);
+	MapBase::operator=(copy);
+	capacity = copy.capacity;
+	if (capacity == 0) return *this;
+	values = allocator.allocate(capacity);      
       }
 
-      MapBase::operator=(copy);
-
-      capacity = copy.capacity;
-      if (capacity == 0) return *this;
-      values = allocator.allocate(capacity);
-
       for (KeyIt it(*MapBase::getGraph()); it != INVALID; ++it) {
 	int id = KeyInfo<Graph, KeyIt>::id(*MapBase::getGraph(), it);
 	allocator.construct(&(values[id]), copy.values[id]);
@@ -142,17 +141,20 @@
      */
     template <typename TT>
     ArrayMap& operator=(const ArrayMap<MapRegistry, TT>& copy) {
-      if (capacity != 0) {
-	MapBase::destroy();
-	allocator.deallocate(values, capacity);
+
+      if (MapBase::getGraph() != copy.getGraph()) {
+	if (capacity != 0) {
+	  MapBase::destroy();
+	  allocator.deallocate(values, capacity);
+	}
+
+	MapBase::operator=(copy);
+
+	capacity = copy.capacity;
+	if (capacity == 0) return *this;
+	values = allocator.allocate(capacity);
       }
 
-      MapBase::operator=(copy);
-
-      capacity = copy.capacity;
-      if (capacity == 0) return *this;
-      values = allocator.allocate(capacity);
-
       for (KeyIt it(*MapBase::getGraph()); it != INVALID; ++it) {
 	int id = KeyInfo<Graph, KeyIt>::id(*MapBase::getGraph(), it);
 	allocator.construct(&(values[id]), copy.values[id]);