-///////////////////////////////////////////////////////////////////////////
-// This program is free software: you can redistribute it and/or modify //
-// it under the terms of the version 3 of the GNU General Public License //
-// as published by the Free Software Foundation. //
-// //
-// This program is distributed in the hope that it will be useful, but //
-// WITHOUT ANY WARRANTY; without even the implied warranty of //
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU //
-// General Public License for more details. //
-// //
-// You should have received a copy of the GNU General Public License //
-// along with this program. If not, see <http://www.gnu.org/licenses/>. //
-// //
-// Written by and Copyright (C) Francois Fleuret //
-// Contact <francois.fleuret@idiap.ch> for comments & bug reports //
-///////////////////////////////////////////////////////////////////////////
+/*
+ * 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>
+ *
+ * This file is part of mtp.
+ *
+ * mtp is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * mtp is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with selector. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
#ifndef MTP_GRAPH_H
#define MTP_GRAPH_H
+#include <iostream>
+
+using namespace std;
+
#include "misc.h"
+#include "path.h"
class Vertex;
class Edge;
class MTPGraph {
- void initialize_work_lengths();
- void update_work_lengths();
- void force_positive_work_lengths();
- void find_shortest_path(Vertex **front, Vertex **new_front);
+
+ // 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();
+
+ // Visit the vertices according to _dp_order and update their
+ // distance from the source
+ void dp_compute_distances();
+
+ // Set in every vertex pred_edge_toward_source correspondingly to
+ // the path of shortest length. The current implementation is
+ // Dijkstra with a Binary Heap (and not with Fibonnaci heap (yet))
+ void find_shortest_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, int *used_edges);
int _nb_vertices, _nb_edges;
Vertex *_source, *_sink;
- Vertex **_front, **_new_front;
+
+ Edge *_edges;
+ Vertex *_vertices;
+
+ // For Dijkstra
+ Vertex **_heap;
+
+ // Updating the distances from the source in that order will work in
+ // the original graph (which has to be a DAG)
+ Vertex **_dp_order;
+
+ // Fills _dp_order
+ void compute_dp_ordering();
public:
- Edge *edges;
- Vertex *vertices;
- MTPGraph(int nb_vertices, int nb_edges, int *from, int *to,
+ // These variables are filled when retrieve_disjoint_paths is called
+ int nb_paths;
+ Path **paths;
+
+ MTPGraph(int nb_vertices, int nb_edges, int *vertex_from, int *vertex_to,
int source, int sink);
~MTPGraph();
- void find_best_paths(scalar_t *lengths, int *result_edge_occupation);
- void print();
- void print_dot();
+ // Compute the family of paths with minimum total length, set the
+ // edge occupied fields accordingly.
+ void find_best_paths(scalar_t *lengths);
+
+ // Retrieve the paths corresponding to the occupied edges, and save
+ // the result in the nb_paths and paths fields. If the paths are not
+ // node-disjoint, there are multiple families of paths that
+ // "explain" the edge occupancies, and this method picks one of them
+ // arbitrarily.
+ void retrieve_disjoint_paths();
+
+ void print(ostream *os);
+ void print_dot(ostream *os);
};
#endif
projects / mtp.git / blobdiff