From: Francois Fleuret <francois@fleuret.org>
Date: Tue, 21 Aug 2012 21:12:09 +0000 (-0700)
Subject: Added a method to save the results in dot format.
X-Git-Url: https://fleuret.org/cgi-bin/gitweb/gitweb.cgi?p=mtp.git;a=commitdiff_plain;h=58f6c3e7578dcef2007819bbdad95d144e547d44

Added a method to save the results in dot format.
---

diff --git a/mtp.cc b/mtp.cc
index 529ba80..94dde64 100644
--- a/mtp.cc
+++ b/mtp.cc
@@ -53,9 +53,9 @@ public:
 class Vertex {
 public:
   int id;
-  // These are the leaving edges
+
   Edge *first_edge;
-  scalar_t distance;
+  scalar_t distance_from_source;
 
   Vertex *pred_vertex;
   Edge *pred_edge;
@@ -63,9 +63,9 @@ public:
   Vertex() { first_edge = 0; }
 
   inline void add_edge(Edge *e) {
-    if(first_edge) { first_edge->pred = e; }
     e->next = first_edge;
     e->pred = 0;
+    if(first_edge) { first_edge->pred = e; }
     first_edge = e;
   }
 
@@ -77,22 +77,25 @@ public:
 };
 
 class Graph {
-public:
+  void initialize_work_lengths();
+  void update_work_length();
+  void find_shortest_path(Vertex **front, Vertex **new_front);
+
   int nb_vertices;
   Edge *edge_heap;
   Vertex *vertices;
   Vertex *source, *sink;
 
+public:
   Graph(int nb_vertices, int nb_edges, int *from, int *to, scalar_t *lengths,
         int source, int sink);
+
   ~Graph();
 
-  void initialize_work_lengths();
-  void update_work_length();
-  void find_shortest_path();
   void find_best_paths();
   void print();
   void print_occupied_edges();
+  void dot_print();
 };
 
 void Graph::print() {
@@ -115,6 +118,23 @@ void Graph::print_occupied_edges() {
   }
 }
 
+void Graph::dot_print() {
+  cout << "digraph {" << endl;
+  cout << "  node[shape=circle];" << endl;
+  for(int n = 0; n < nb_vertices; n++) {
+    for(Edge *e = vertices[n].first_edge; e; e = e->next) {
+      int a = n, b = e->terminal_vertex->id;
+      if(e->occupied) {
+        int c = a; a = b; b = c;
+        cout << "  " << a << " -> " << b << " [style=bold,color=black,label=\"" << -e->length << "\"];" << endl;
+      } else {
+        cout << "  " << a << " -> " << b << " [color=gray,label=\"" << e->length << "\"];" << endl;
+      }
+    }
+  }
+  cout << "}" << endl;
+}
+
 Graph::Graph(int nb_vrt, int nb_edges,
              int *from, int *to, scalar_t *lengths,
              int src, int snk) {
@@ -159,16 +179,14 @@ void Graph::initialize_work_lengths() {
 
 void Graph::update_work_length() {
   for(int n = 0; n < nb_vertices; n++) {
-    scalar_t d = vertices[n].distance;
+    scalar_t d = vertices[n].distance_from_source;
     for(Edge *e = vertices[n].first_edge; e; e = e->next) {
-      e->work_length += d - e->terminal_vertex->distance;
+      e->work_length += d - e->terminal_vertex->distance_from_source;
     }
   }
 }
 
-void Graph::find_shortest_path() {
-  Vertex **front = new Vertex *[nb_vertices];
-  Vertex **new_front = new Vertex *[nb_vertices];
+void Graph::find_shortest_path(Vertex **front, Vertex **new_front) {
   Vertex **tmp_front;
   int tmp_front_size;
   Vertex *v, *tv;
@@ -187,24 +205,24 @@ void Graph::find_shortest_path() {
 #endif
 
   for(int v = 0; v < nb_vertices; v++) {
-    vertices[v].distance = FLT_MAX;
+    vertices[v].distance_from_source = FLT_MAX;
     vertices[v].pred_vertex = 0;
     vertices[v].pred_edge = 0;
   }
 
   int front_size = 0, new_front_size;
   front[front_size++] = source;
-  source->distance = 0;
+  source->distance_from_source = 0;
 
   do {
     new_front_size = 0;
     for(int f = 0; f < front_size; f++) {
       v = front[f];
       for(Edge *e = v->first_edge; e; e = e->next) {
-        d = v->distance + e->work_length;
+        d = v->distance_from_source + e->work_length;
         tv = e->terminal_vertex;
-        if(d < tv->distance) {
-          tv->distance = d;
+        if(d < tv->distance_from_source) {
+          tv->distance_from_source = d;
           tv->pred_vertex = v;
           tv->pred_edge = e;
           new_front[new_front_size++] = tv;
@@ -220,41 +238,29 @@ void Graph::find_shortest_path() {
     new_front_size = front_size;
     front_size = tmp_front_size;
   } while(front_size > 0);
-
-  delete[] front;
-  delete[] new_front;
 }
 
 void Graph::find_best_paths() {
+  Vertex **front = new Vertex *[nb_vertices];
+  Vertex **new_front = new Vertex *[nb_vertices];
+
   scalar_t total_length;
 
   initialize_work_lengths();
 
   do {
-#ifdef VERBOSE
-    print();
-#endif
-
     total_length = 0.0;
-    find_shortest_path();
+    find_shortest_path(front, new_front);
     update_work_length();
 
     // Do we reach the sink?
     if(sink->pred_edge) {
 
-#ifdef VERBOSE
-      cout << "VERBOSE there is a path reaching the sink" << endl;
-#endif
-
       // If yes, compute the length of the best path
       for(Vertex *v = sink; v->pred_edge; v = v->pred_vertex) {
         total_length += v->pred_edge->length;
       }
 
-#ifdef VERBOSE
-      cout << "VERBOSE total_length " << total_length << endl;
-#endif
-
       // If that length is negative
       if(total_length < 0.0) {
         // Invert all the edges along the best path
@@ -270,6 +276,24 @@ void Graph::find_best_paths() {
       }
     }
   } while(total_length < 0.0);
+
+  // // We put all occupied edges back to their original orientations
+  // for(int n = 0; n < nb_vertices; n++) {
+    // Vertex *v = &vertices[n];
+    // for(Edge *e = v->first_edge; e; e = e->next) {
+      // if(e->occupied) {
+        // e->terminal_vertex = v->pred_vertex;
+        // e->length = - e->length;
+        // e->work_length = 0;
+        // v->pred_vertex->del_edge(e);
+        // v->add_edge(e);
+      // }
+    // }
+  // }
+
+
+  delete[] front;
+  delete[] new_front;
 }
 
 //////////////////////////////////////////////////////////////////////
@@ -291,10 +315,10 @@ int main(int argc, char **argv) {
     (*file) >> nb_vertices >> nb_edges;
     (*file) >> source >> sink;
 
-    cout << "INPUT nb_edges " << nb_edges << endl;
-    cout << "INPUT nb_vertices " << nb_vertices << endl;
-    cout << "INPUT source " << source << endl;
-    cout << "INPUT sink " << sink << endl;
+    // cout << "INPUT nb_edges " << nb_edges << endl;
+    // cout << "INPUT nb_vertices " << nb_vertices << endl;
+    // cout << "INPUT source " << source << endl;
+    // cout << "INPUT sink " << sink << endl;
 
     scalar_t *el = new scalar_t[nb_edges];
     int *ea = new int[nb_edges];
@@ -302,13 +326,17 @@ int main(int argc, char **argv) {
 
     for(int e = 0; e < nb_edges; e++) {
       (*file) >> ea[e] >> eb[e] >> el[e];
-      cout << "INPUT_EDGE " << ea[e] << " " << eb[e] << " " << el[e] << endl;
     }
 
+    // for(int e = 0; e < nb_edges; e++) {
+      // cout << "INPUT_EDGE " << ea[e] << " " << eb[e] << " " << el[e] << endl;
+    // }
+
     Graph graph(nb_vertices, nb_edges, ea, eb, el, source, sink);
 
     graph.find_best_paths();
-    graph.print_occupied_edges();
+    // graph.print_occupied_edges();
+    graph.dot_print();
 
     delete[] el;
     delete[] ea;