#include "mtp_graph.h"
+#include <cmath>
#include <float.h>
using namespace std;
class Vertex {
public:
- Edge *leaving_edges;
scalar_t distance_from_source;
Edge *pred_edge_toward_source;
+
+ Edge *leaving_edge_list_root;
Vertex **heap_slot;
Vertex();
//////////////////////////////////////////////////////////////////////
Vertex::Vertex() {
- leaving_edges = 0;
+ leaving_edge_list_root = 0;
}
void Vertex::add_leaving_edge(Edge *e) {
- e->next_leaving_edge = leaving_edges;
+ e->next_leaving_edge = leaving_edge_list_root;
e->pred_leaving_edge = 0;
- if(leaving_edges) { leaving_edges->pred_leaving_edge = e; }
- leaving_edges = e;
+ if(leaving_edge_list_root) {
+ leaving_edge_list_root->pred_leaving_edge = e;
+ }
+ leaving_edge_list_root = e;
}
void Vertex::del_leaving_edge(Edge *e) {
- if(e == leaving_edges) {
- leaving_edges = e->next_leaving_edge;
+ if(e == leaving_edge_list_root) {
+ leaving_edge_list_root = e->next_leaving_edge;
}
if(e->pred_leaving_edge) {
e->pred_leaving_edge->next_leaving_edge = e->next_leaving_edge;
//////////////////////////////////////////////////////////////////////
-static int compare_vertex(const void *v1, const void *v2) {
+static int compare_vertices_on_distance(const void *v1, const void *v2) {
scalar_t delta =
(*((Vertex **) v1))->distance_from_source -
(*((Vertex **) v2))->distance_from_source;
else return 0;
}
+//////////////////////////////////////////////////////////////////////
+
MTPGraph::MTPGraph(int nb_vertices, int nb_edges,
int *vertex_from, int *vertex_to,
int source, int sink) {
paths = 0;
nb_paths = 0;
- if(compute_dp_ranks()) {
- // Here the distance_from_source field of every vertex is the
- // number of DP iterations needed to update it. Hence we only have
- // to process the vertex in that order.
- for(int v = 0; v < _nb_vertices; v++) { _dp_order[v] = &_vertices[v]; }
- qsort(_dp_order, _nb_vertices, sizeof(Vertex *), compare_vertex);
- } else {
- cerr << __FILE__ << ": This graph is not a DAG." << endl;
- abort();
- }
+ compute_dp_ranks();
+ for(int v = 0; v < _nb_vertices; v++) { _dp_order[v] = &_vertices[v]; }
+ qsort(_dp_order, _nb_vertices, sizeof(Vertex *), compare_vertices_on_distance);
}
MTPGraph::~MTPGraph() {
delete[] paths;
}
-int MTPGraph::compute_dp_ranks() {
+//////////////////////////////////////////////////////////////////////
+
+void MTPGraph::compute_dp_ranks() {
Vertex *v;
Edge *e;
+ int tv;
// This procedure computes for each node the longest link from the
// source and abort if the graph is not a DAG. It works by removing
// rank of a node is the iteration at which is it removed, and we
// set the distance_from_source fields to this value.
- Vertex **with_predecessor = new Vertex *[_nb_vertices];
+ 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;
- // All the nodes are with_predecessor at first
for(int k = 0; k < _nb_vertices; k++) {
- _vertices[k].distance_from_source = 0;
- with_predecessor[k] = &_vertices[k];
+ nb_predecessors[k] = 0;
}
- scalar_t rank = 1;
- int nb_with_predecessor = _nb_vertices, pred_nb_with_predecessor;
-
- do {
- // We set the distance_from_source field of all the vertices with incoming
- // edges to the current rank value
- for(int f = 0; f < nb_with_predecessor; f++) {
- v = with_predecessor[f];
- for(e = v->leaving_edges; e; e = e->next_leaving_edge) {
- e->terminal_vertex->distance_from_source = rank;
- }
+ for(int k = 0; k < _nb_vertices; k++) {
+ v = _vertices + k;
+ for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {
+ tv = e->terminal_vertex - _vertices;
+ nb_predecessors[tv]++;
}
+ }
- pred_nb_with_predecessor = nb_with_predecessor;
- nb_with_predecessor = 0;
+ nb_without_predecessors = 0;
+ for(int k = 0; k < _nb_vertices; k++) {
+ if(nb_predecessors[k] == 0) {
+ without_predecessors[nb_without_predecessors++] = k;
+ }
+ }
- // We keep all the vertices with incoming nodes
- for(int f = 0; f < pred_nb_with_predecessor; f++) {
- v = with_predecessor[f];
- if(v->distance_from_source == rank) {
- with_predecessor[nb_with_predecessor++] = v;
+ 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];
+ v->distance_from_source = rank;
+ for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {
+ tv = 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;
+ }
}
}
+ swap(without_predecessors, new_without_predecessors);
+ nb_without_predecessors = new_nb_without_predecessors;
rank++;
- } while(nb_with_predecessor < pred_nb_with_predecessor);
+ }
- delete[] with_predecessor;
+ for(int k = 0; k < _nb_vertices; k++) {
+ if(nb_predecessors[k] > 0) {
+ cerr << __FILE__ << ": The graph is not a DAG." << endl;
+ abort();
+ }
+ }
- return nb_with_predecessor == 0;
+ delete[] nb_predecessors;
+ delete[] without_predecessors;
+ delete[] new_without_predecessors;
}
//////////////////////////////////////////////////////////////////////
for(int k = 0; k < _nb_edges; k++) {
Edge *e = _edges + k;
(*os) << e->origin_vertex - _vertices
- << " -> "
- << e->terminal_vertex - _vertices
- << " "
- << e->length;
- if(e->occupied) {
- (*os) << " *";
- }
+ << " -> "
+ << e->terminal_vertex - _vertices
+ << " (" << e->length << ")";
+ if(e->occupied) { (*os) << " *"; }
(*os) << endl;
}
}
for(int k = 0; k < _nb_vertices; k++) {
v = _dp_order[k];
- for(e = v->leaving_edges; e; e = e->next_leaving_edge) {
+ for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {
d = v->distance_from_source + e->positivized_length;
tv = e->terminal_vertex;
if(d < tv->distance_from_source) {
// Now update the neighbors of the node currently closest to the
// source
- for(e = v->leaving_edges; e; e = e->next_leaving_edge) {
+ for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {
d = v->distance_from_source + e->positivized_length;
tv = e->terminal_vertex;
if(d < tv->distance_from_source) {
} else l++;
nb_occupied_next = 0;
- for(f = e->terminal_vertex->leaving_edges; f; f = f->next_leaving_edge) {
+ for(f = e->terminal_vertex->leaving_edge_list_root; f; f = f->next_leaving_edge) {
if(f->occupied) { nb_occupied_next++; next = f; }
}
delete[] paths;
nb_paths = 0;
- for(e = _source->leaving_edges; e; e = e->next_leaving_edge) {
+ for(e = _source->leaving_edge_list_root; e; e = e->next_leaving_edge) {
if(e->occupied) { nb_paths++; }
}
paths = new Path *[nb_paths];
p = 0;
- for(e = _source->leaving_edges; e; e = e->next_leaving_edge) {
+ for(e = _source->leaving_edge_list_root; e; e = e->next_leaving_edge) {
if(e->occupied) {
l = retrieve_one_path(e, 0);
paths[p] = new Path(l);
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