Graphical Model : message pending

2010-08-25 03:18:14 +00:00
parent f71a91b9a2
commit 4b37da6908
1 changed files with 63 additions and 0 deletions
@@ -0,0 +1,63 @@
+#ifndef __MESSAGE_PENDING_INFERENCE_H
+#define __MESSAGE_PENDING_INFERENCE_H
+
+#include "gm.h"
+
+BEGIN_GRAPHICAL_MODEL_NAMESPACE;
+
+/** The sum-product algorithm with message priority queue:
+  * + Messages are picked to update according to theirs changes in previous iteration.
+  * + Messages are propagated along all edges for a certain number of iterations
+  *   while the total change of messages is bigger than change tolerance.
+  * + Messages are used to calculate beliefs of variable-vertex and average of factor-vertex.
+  */
+template <typename _F>
+    class MessagePriorityInference : public SumProductInference<_F>
+{
+public:
+  typedef SumProductInference<_F>                            _Base;
+  typedef typename _Base::factor_type                        factor_type;         // map from Assignment --> factor_value_type
+  typedef typename _Base::factor_value_type                  factor_value_type;   // a numeric type
+  typedef typename _Base::graph_type                         graph_type;          // FactorGraph<factor_type>
+  typedef typename _Base::vertex_type                        vertex_type;         // Vertex* (see factor_graph.h)
+  typedef typename _Base::vertex_vector_type                 vertex_vector_type;  // Vector<vertex_type>
+  typedef typename _Base::belief_type                        belief_type;         // Map<Value, factor_value_type>
+  typedef typename _Base::belief_map_type                    belief_map_type;     // Map<vertex_type, belief_type>
+  typedef typename _Base::message_type                       message_type;        // Map<Value, factor_value_type>
+  typedef typename _Base::messages_map_type                  messages_map_type;   // Map<vertex_type, Map<vertex_type, message_type> >
+                                                                                  // usage: message[u][v] where u,v are vertex_type
+public:
+  /** Preparing inference on a graph */
+  MessagePriorityInference(const graph_type& graph, ConvergenceMeasure cvm = ConvergenceMeasure())
+    : _Base(graph, cvm) {}
+
+  /** The inference algorithm */
+  void run();
+protected:
+  typedef std::pair<vertex_type, vertex_type>                                vertex_pair_type;
+  typedef std::pair< vertex_pair_type, factor_value_type>                    msg_double_type;
+  typedef Vector<msg_double_type>                                            msg_double_vector_type;
+  struct MsgCompare
+  {
+    bool operator() (const msg_double_type& lhs, const msg_double_type& rhs) const
+    {
+      return lhs.second < rhs.second;
+    }
+  };
+  typedef PriorityQueue<msg_double_type, msg_double_vector_type, MsgCompare> msg_double_queue_type;
+
+  /** Priority queue of messages */
+  msg_double_queue_type message_queue_;
+  /** Total change of messages in an iteration */
+  factor_value_type change_sum;
+
+  /** Init the message queue by updating all messages once */
+  void initMessageQueue();
+
+  /** The L1 difference between two messages */
+  factor_value_type difference(const message_type& oldMsg, const message_type& newMsg);
+};
+
+END_GRAPHICAL_MODEL_NAMESPACE;
+
+#endif