Ticket #311: 311-4-e8953d052534.patch

lemon/list_graph.h

@@ -1311 +1311 @@
       Parent::clear();
     }
 
+    /// Reserve memory for nodes.
+
+    /// Using this function, it is possible to avoid superfluous memory
+    /// allocation: if you know that the graph you want to build will
+    /// be large (e.g. it will contain millions of nodes and/or edges),
+    /// then it is worth reserving space for this amount before starting
+    /// to build the graph.
+    /// \sa reserveEdge()
+    void reserveNode(int n) { nodes.reserve(n); };
+
+    /// Reserve memory for edges.
+
+    /// Using this function, it is possible to avoid superfluous memory
+    /// allocation: if you know that the graph you want to build will
+    /// be large (e.g. it will contain millions of nodes and/or edges),
+    /// then it is worth reserving space for this amount before starting
+    /// to build the graph.
+    /// \sa reserveNode()
+    void reserveEdge(int m) { arcs.reserve(2 * m); };
+
     /// \brief Class to make a snapshot of the graph and restore
     /// it later.
     ///

lemon/smart_graph.h

@@ -691 +691 @@
       Parent::clear();
     }
 
+    /// Reserve memory for nodes.
+
+    /// Using this function, it is possible to avoid superfluous memory
+    /// allocation: if you know that the graph you want to build will
+    /// be large (e.g. it will contain millions of nodes and/or edges),
+    /// then it is worth reserving space for this amount before starting
+    /// to build the graph.
+    /// \sa reserveEdge()
+    void reserveNode(int n) { nodes.reserve(n); };
+
+    /// Reserve memory for edges.
+
+    /// Using this function, it is possible to avoid superfluous memory
+    /// allocation: if you know that the graph you want to build will
+    /// be large (e.g. it will contain millions of nodes and/or edges),
+    /// then it is worth reserving space for this amount before starting
+    /// to build the graph.
+    /// \sa reserveNode()
+    void reserveEdge(int m) { arcs.reserve(2 * m); };
+
   public:
 
     class Snapshot;

test/digraph_test.cc

@@ -35 +35 @@
   checkGraphNodeList(G, 0);
   checkGraphArcList(G, 0);
 
+  G.reserveNode(3);
+  G.reserveArc(4);
+
   Node
     n1 = G.addNode(),
     n2 = G.addNode(),

test/graph_test.cc

@@ -38 +38 @@
   checkGraphEdgeList(G, 0);
   checkGraphArcList(G, 0);
 
+  G.reserveNode(3);
+  G.reserveEdge(3);
+
   Node
     n1 = G.addNode(),
     n2 = G.addNode(),