# HG changeset patch
# User ladanyi
# Date 1138572405 0
# Node ID 9704601de87f565d016e393811da1c043b2bb70c
# Parent  09415ae11103d45885cb305db0068986247facf1
demo for simann

diff -r 09415ae11103 -r 9704601de87f demo/simann_maxcut_demo.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demo/simann_maxcut_demo.cc	Sun Jan 29 22:06:45 2006 +0000
@@ -0,0 +1,123 @@
+/* -*- C++ -*-
+ * demo/simann_maxcut_demo.cc - Part of LEMON, a generic C++ optimization
+ * library
+ *
+ * Copyright (C) 2006 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
+ * (Egervary Research Group on Combinatorial Optimization, EGRES).
+ *
+ * Permission to use, modify and distribute this software is granted
+ * provided that this copyright notice appears in all copies. For
+ * precise terms see the accompanying LICENSE file.
+ *
+ * This software is provided "AS IS" with no warranty of any kind,
+ * express or implied, and with no claim as to its suitability for any
+ * purpose.
+ *
+ */
+
+/// \ingroup demos
+/// \file
+/// \brief A program demonstrating the simulated annealing algorithm class.
+///
+/// This program tries to find a maximal cut in a graph using simulated
+/// annealing. It starts from a random solution and then in each step it
+/// chooses a node and moves it to the other side of the cut.
+///
+/// \include simann_maxcut_demo.cc
+
+#include <iostream>
+#include <cstdlib>
+
+#include <lemon/simann.h>
+#include <lemon/list_graph.h>
+#include <lemon/graph_reader.h>
+
+using namespace lemon;
+
+typedef ListGraph Graph;
+typedef Graph::Node Node;
+typedef Graph::Edge Edge;
+typedef Graph::NodeIt NodeIt;
+typedef Graph::EdgeIt EdgeIt;
+typedef Graph::OutEdgeIt OutEdgeIt;
+typedef Graph::InEdgeIt InEdgeIt;
+
+class Entity : public EntityBase
+{
+  public:
+    Graph& g;
+    Graph::EdgeMap<int>& w;
+    Graph::NodeMap<bool> a;
+    int sum;
+    Node last_moved;
+    Entity(Graph& _g, Graph::EdgeMap<int>& _w) : g(_g), w(_w), a(_g) {}
+    double mutate() {
+      static const int node_num = countNodes(g);
+      int i = 1 + (int) (node_num * (rand() / (RAND_MAX + 1.0)));
+      NodeIt n(g);
+      int j = 1;
+      while (j < i) {
+        ++n;
+        ++j;
+      }
+      for (OutEdgeIt e(g, n); e != INVALID; ++e) {
+        if (a[n] != a[g.target(e)]) sum -= w[e];
+        if (a[n] == a[g.target(e)]) sum += w[e];
+      }
+      for (InEdgeIt e(g, n); e != INVALID; ++e) {
+        if (a[g.source(e)] != a[n]) sum -= w[e];
+        if (a[g.source(e)] == a[n]) sum += w[e];
+      }
+      bool b = a[n];
+      a[n] = !b;
+      last_moved = n;
+      return -sum;
+    }
+    void revert() {
+      for (OutEdgeIt e(g, last_moved); e != INVALID; ++e) {
+        if (a[last_moved] != a[g.target(e)]) sum -= w[e];
+        if (a[last_moved] == a[g.target(e)]) sum += w[e];
+      }
+      for (InEdgeIt e(g, last_moved); e != INVALID; ++e) {
+        if (a[g.source(e)] != a[last_moved]) sum -= w[e];
+        if (a[g.source(e)] == a[last_moved]) sum += w[e];
+      }
+      bool b = a[last_moved];
+      a[last_moved] = !b;
+    }
+    Entity* clone() { return new Entity(*this); }
+    void randomize() {
+      for (NodeIt n(g); n != INVALID; ++n)
+        a[n] = false;
+      for (NodeIt n(g); n != INVALID; ++n)
+        if (rand() < 0.5) a[n] = true;
+      sum = 0;
+      for (EdgeIt e(g); e != INVALID; ++e)
+        if (a[g.source(e)] != a[g.target(e)])
+          sum += w[e];
+    }
+};
+
+int main()
+{
+  Graph g;
+  Graph::EdgeMap<int> w(g);
+
+  GraphReader<Graph> reader("simann_maxcut_demo.lgf", g);
+  reader.readEdgeMap("weight", w);
+  reader.run();
+
+  Entity e(g, w);
+
+  SimAnn simann;
+  SimpleController ctrl;
+  simann.setController(ctrl);
+  simann.setEntity(e);
+  simann.run();
+  
+  Entity* be = (Entity *) simann.getBestEntity();
+  std::cout << be->sum << std::endl;
+  for (NodeIt n(g); n != INVALID; ++n)
+    if (be->a[n]) std::cout << g.id(n) << ": 1" << std::endl;
+    else std::cout << g.id(n) << ": 0" << std::endl;
+}
diff -r 09415ae11103 -r 9704601de87f demo/simann_maxcut_demo.lgf
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demo/simann_maxcut_demo.lgf	Sun Jan 29 22:06:45 2006 +0000
@@ -0,0 +1,22 @@
+@nodeset
+label
+0
+1
+2
+3
+4
+5
+6
+@edgeset
+        weight
+0   3   1
+0   4   1
+1   5   1
+5   2   1
+6   2   1
+0   1   1
+2   1   1
+3   4   1
+4   5   1
+5   6   1
+@end