Simplified compute_dp_ranks.

[mtp.git] / mtp_graph.cc

diff --git a/mtp_graph.cc b/mtp_graph.cc
index 0fe3cf0..80f9f05 100644 (file)
--- a/mtp_graph.cc
+++ b/mtp_graph.cc
@@ -159,10 +159,10 @@ MTPGraph::MTPGraph(int nb_vertices, int nb_edges,
   _sink = &_vertices[sink];
 
   for(int e = 0; e < nb_edges; e++) {
-    _vertices[vertex_from[e]].add_leaving_edge(_edges + e);
+    _vertices[vertex_from[e]].add_leaving_edge(&_edges[e]);
     _edges[e].occupied = 0;
-    _edges[e].origin_vertex = _vertices + vertex_from[e];
-    _edges[e].terminal_vertex = _vertices + vertex_to[e];
+    _edges[e].origin_vertex = &_vertices[vertex_from[e]];
+    _edges[e].terminal_vertex = &_vertices[vertex_to[e]];
   }
 
   for(int v = 0; v < _nb_vertices; v++) {
@@ -205,67 +205,61 @@ void MTPGraph::compute_dp_ranks() {
   // set the distance_from_source fields to this value.
 
   int *nb_predecessors = new int[_nb_vertices];
-  int *without_predecessors = new int[_nb_vertices];
-  int *new_without_predecessors = new int[_nb_vertices];
-  int nb_without_predecessors, new_nb_without_predecessors;
+  Vertex **bunch = new Vertex *[_nb_vertices];
+
+  Vertex **already_processed = bunch, **front = bunch, **fresh = bunch;
 
   for(int k = 0; k < _nb_vertices; k++) {
     nb_predecessors[k] = 0;
   }
 
   for(int k = 0; k < _nb_vertices; k++) {
-    v = _vertices + k;
+    v = &_vertices[k];
     for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {
-      tv = e->terminal_vertex - _vertices;
+      tv = int(e->terminal_vertex - _vertices);
       nb_predecessors[tv]++;
     }
   }
 
-  nb_without_predecessors = 0;
   for(int k = 0; k < _nb_vertices; k++) {
     if(nb_predecessors[k] == 0) {
-      without_predecessors[nb_without_predecessors++] = k;
+      *(front++) = _vertices + k;
     }
   }
 
   scalar_t rank = 1;
-  while(nb_without_predecessors > 0) {
-    new_nb_without_predecessors = 0;
-    for(int l = 0; l < nb_without_predecessors; l++) {
-      v = _vertices + without_predecessors[l];
+  while(already_processed < front) {
+    fresh = front;
+    while(already_processed < front) {
+      v = *(already_processed++);
       v->distance_from_source = rank;
       for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {
-        tv = e->terminal_vertex - _vertices;
+        tv = int(e->terminal_vertex - _vertices);
         nb_predecessors[tv]--;
         ASSERT(nb_predecessors[tv] >= 0);
         if(nb_predecessors[tv] == 0) {
-          new_without_predecessors[new_nb_without_predecessors++] = tv;
+          *(fresh++) = e->terminal_vertex;
         }
       }
     }
-
-    swap(without_predecessors, new_without_predecessors);
-    nb_without_predecessors = new_nb_without_predecessors;
+    front = fresh;
     rank++;
   }
 
-  for(int k = 0; k < _nb_vertices; k++) {
-    if(nb_predecessors[k] > 0) {
-      cerr << __FILE__ << ": The graph is not a DAG." << endl;
-      abort();
-    }
+  if(already_processed < bunch + _nb_vertices) {
+    cerr << __FILE__ << ": The graph is not a DAG." << endl;
+    abort();
   }
 
   delete[] nb_predecessors;
-  delete[] without_predecessors;
-  delete[] new_without_predecessors;
+  delete[] bunch;
 }
 
 //////////////////////////////////////////////////////////////////////
 
 void MTPGraph::print(ostream *os) {
   for(int k = 0; k < _nb_edges; k++) {
-    Edge *e = _edges + k;
+    Edge *e = &_edges[k];
     (*os) << e->origin_vertex - _vertices
           << " -> "
           << e->terminal_vertex - _vertices
@@ -283,7 +277,7 @@ void MTPGraph::print_dot(ostream *os) {
   (*os) << "        " << _source - _vertices << " [peripheries=2];" << endl;
   (*os) << "        " << _sink - _vertices << " [peripheries=2];" << endl;
   for(int k = 0; k < _nb_edges; k++) {
-    Edge *e = _edges + k;
+    Edge *e = &_edges[k];
     (*os) << "        "
           << e->origin_vertex - _vertices
           << " -> "
@@ -301,7 +295,7 @@ void MTPGraph::print_dot(ostream *os) {
 
 void MTPGraph::update_positivized_lengths() {
   for(int k = 0; k < _nb_edges; k++) {
-    Edge *e = _edges + k;
+    Edge *e = &_edges[k];
     e->positivized_length +=
       e->origin_vertex->distance_from_source - e->terminal_vertex->distance_from_source;
   }
@@ -313,7 +307,7 @@ void MTPGraph::force_positivized_lengths() {
   scalar_t max_error = 0.0;
 #endif
   for(int k = 0; k < _nb_edges; k++) {
-    Edge *e = _edges + k;
+    Edge *e = &_edges[k];
 
     if(e->positivized_length < 0) {
 #ifdef VERBOSE
@@ -456,7 +450,7 @@ void MTPGraph::find_best_paths(scalar_t *lengths) {
   // Put back the graph in its original state (i.e. invert edges which
   // have been inverted in the process)
   for(int k = 0; k < _nb_edges; k++) {
-    e = _edges + k;
+    e = &_edges[k];
     if(e->occupied) { e->invert(); }
   }
 }
@@ -466,13 +460,13 @@ int MTPGraph::retrieve_one_path(Edge *e, Path *path) {
   int l = 0, nb_occupied_next;
 
   if(path) {
-    path->nodes[l++] = e->origin_vertex - _vertices;
+    path->nodes[l++] = int(e->origin_vertex - _vertices);
     path->length = e->length;
   } else l++;
 
   while(e->terminal_vertex != _sink) {
     if(path) {
-      path->nodes[l++] = e->terminal_vertex - _vertices;
+      path->nodes[l++] = int(e->terminal_vertex - _vertices);
       path->length += e->length;
     } else l++;
 
@@ -497,7 +491,7 @@ int MTPGraph::retrieve_one_path(Edge *e, Path *path) {
   }
 
   if(path) {
-    path->nodes[l++] = e->terminal_vertex - _vertices;
+    path->nodes[l++] = int(e->terminal_vertex - _vertices);
     path->length += e->length;
   } else l++;