X-Git-Url: https://fleuret.org/cgi-bin/gitweb/gitweb.cgi?a=blobdiff_plain;f=mtp_graph.h;h=f28e460be9ef99b9b9fdca50363fc36e6a0d4cab;hb=09c2607f1569a54f9f77ee5006148937044ee79d;hp=bd805c2b2c863b1c75aa0672f0ede48e267a9862;hpb=68d9c4f175f774d851a32f6069ad04b31924bfac;p=mtp.git

diff --git a/mtp_graph.h b/mtp_graph.h
index bd805c2..f28e460 100644
--- a/mtp_graph.h
+++ b/mtp_graph.h
@@ -1,7 +1,7 @@
 
 /*
- *  mtp is the ``Multi Tracked Path'', an implementation of the
- *  k-shortest path algorithm for multi-target tracking.
+ *  mtp is the ``Multi Tracked Paths'', an implementation of the
+ *  k-shortest paths algorithm for multi-target tracking.
  *
  *  Copyright (c) 2012 Idiap Research Institute, http://www.idiap.ch/
  *  Written by Francois Fleuret <francois.fleuret@idiap.ch>
@@ -37,15 +37,31 @@ class Vertex;
 class Edge;
 
 class MTPGraph {
+  // Uses the estimated vertex distances to the source to make all the
+  // edge lengths positive, resulting in an identical added value to
+  // all the paths from the same initial node to the same final node
+  // (in particular from source to sink)
   void update_positivized_lengths();
+
+  // It may happen that numerical errors in update_positivized_lengths
+  // make the resulting lengths negative, albeit very small. The
+  // following method forces all negative lengths to zero, and prints
+  // the total correction when compiled in VERBOSE mode.
   void force_positivized_lengths();
-  // Set the edge pred_edge_toward_source correspondingly to the path
-  // of shortest length.
+
+  // Set in every vertex pred_edge_toward_source correspondingly to
+  // the path of shortest length. The current implementation is not
+  // Dijkstra's!
   void find_shortest_path();
-  // Follows the path starting on edge e and returns its length. If
-  // nodes is non-null, stores in it the nodes met along the path.
+
+  // Follows the path starting on edge e and returns the number of
+  // nodes to reach the sink. If path is non-null, stores in it the
+  // nodes met along the path, and computes path->length properly.
   int retrieve_one_path(Edge *e, Path *path);
 
+  // Returns if the graph is a DAG
+  int is_dag();
+
   Vertex **_front, **_new_front;
 
   int _nb_vertices, _nb_edges;
@@ -60,12 +76,17 @@ public:
   int nb_paths;
   Path **paths;
 
-  MTPGraph(int nb_vertices, int nb_edges, int *from, int *to,
+  MTPGraph(int nb_vertices, int nb_edges, int *vertex_from, int *vertex_to,
            int source, int sink);
 
   ~MTPGraph();
 
+  // Compute the family of path with minimum total length, set the
+  // edge occupied fields accordingly.
   void find_best_paths(scalar_t *lengths);
+
+  // Retrieve the path corresponding to the occupied edges, and save
+  // the result in the nb_paths and paths fields.
   void retrieve_disjoint_paths();
 
   void print(ostream *os);