using namespace std;
-typedef float scalar_t;
+#include "mtp_graph.h"
-#ifdef DEBUG
-#define ASSERT(x) if(!(x)) { \
- std::cerr << "ASSERT FAILED IN " << __FILE__ << ":" << __LINE__ << endl; \
- abort(); \
-}
-#else
-#define ASSERT(x)
-#endif
-
-class Vertex;
-
-class Edge {
-public:
- int id, occupied;
- scalar_t length, work_length;
- Vertex *terminal_vertex;
- Edge *next, *pred;
-};
-
-class Vertex {
-public:
- int id, iteration;
- Edge *root_edge;
- scalar_t distance_from_source;
- Vertex *pred_vertex;
- Edge *pred_edge;
-
- Vertex() { root_edge = 0; }
-
- inline void add_edge(Edge *e) {
- e->next = root_edge;
- e->pred = 0;
- if(root_edge) { root_edge->pred = e; }
- root_edge = e;
- }
-
- inline void del_edge(Edge *e) {
- if(e == root_edge) { root_edge = e->next; }
- if(e->pred) { e->pred->next = e->next; }
- if(e->next) { e->next->pred = e->pred; }
- }
-};
-
-class Graph {
- 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 find_best_paths(int *result_edge_occupation);
- void print();
-};
-
-void Graph::print() {
- for(int n = 0; n < nb_vertices; n++) {
- for(Edge *e = vertices[n].root_edge; e; e = e->next) {
- cout << n << " -> " << e->terminal_vertex->id << " " << e->length;
- if(e->occupied) {
- cout << " *";
- }
- cout << endl;
- }
- }
-}
-
-Graph::Graph(int nb_vrt, int nb_edges,
- int *from, int *to, scalar_t *lengths,
- int src, int snk) {
- nb_vertices = nb_vrt;
-
- edge_heap = new Edge[nb_edges];
- vertices = new Vertex[nb_vertices];
-
- source = &vertices[src];
- sink = &vertices[snk];
-
- for(int v = 0; v < nb_vertices; v++) {
- vertices[v].id = v;
- }
-
- for(int e = 0; e < nb_edges; e++) {
- vertices[from[e]].add_edge(&edge_heap[e]);
- edge_heap[e].occupied = 0;
- edge_heap[e].id = e;
- edge_heap[e].length = lengths[e];
- edge_heap[e].terminal_vertex = &vertices[to[e]];
- }
-}
-
-Graph::~Graph() {
- delete[] vertices;
- delete[] edge_heap;
-}
-
-void Graph::initialize_work_lengths() {
- scalar_t length_min = 0;
- for(int n = 0; n < nb_vertices; n++) {
- for(Edge *e = vertices[n].root_edge; e; e = e->next) {
- length_min = min(e->length, length_min);
- }
- }
- for(int n = 0; n < nb_vertices; n++) {
- for(Edge *e = vertices[n].root_edge; e; e = e->next) {
- e->work_length = e->length - length_min;
- }
- }
-}
-
-void Graph::update_work_length() {
- for(int n = 0; n < nb_vertices; n++) {
- scalar_t d = vertices[n].distance_from_source;
- for(Edge *e = vertices[n].root_edge; e; e = e->next) {
- e->work_length += d - e->terminal_vertex->distance_from_source;
- }
- }
-}
-
-void Graph::find_shortest_path(Vertex **front, Vertex **new_front) {
- Vertex **tmp_front;
- int tmp_front_size;
- Vertex *v, *tv;
- scalar_t d;
-
-#ifdef VERBOSE
- scalar_t residual_error = 0.0;
-#endif
- for(int n = 0; n < nb_vertices; n++) {
- for(Edge *e = vertices[n].root_edge; e; e = e->next) {
- if(e->work_length < 0) {
-#ifdef VERBOSE
- residual_error -= e->work_length;
-#endif
- e->work_length = 0.0;
- }
- }
- }
-#ifdef VERBOSE
- cerr << "residual_error " << residual_error << endl;
-#endif
-
- for(int v = 0; v < nb_vertices; v++) {
- vertices[v].distance_from_source = FLT_MAX;
- vertices[v].pred_vertex = 0;
- vertices[v].pred_edge = 0;
- vertices[v].iteration = 0;
- }
-
- int iteration = 0;
-
- int front_size = 0, new_front_size;
- front[front_size++] = source;
- source->distance_from_source = 0;
-
- do {
- new_front_size = 0;
- iteration++;
- for(int f = 0; f < front_size; f++) {
- v = front[f];
- for(Edge *e = v->root_edge; e; e = e->next) {
- d = v->distance_from_source + e->work_length;
- tv = e->terminal_vertex;
- if(d < tv->distance_from_source) {
- tv->distance_from_source = d;
- tv->pred_vertex = v;
- tv->pred_edge = e;
- if(tv->iteration < iteration) {
- new_front[new_front_size++] = tv;
- tv->iteration = iteration;
- }
- }
- }
- }
-
- tmp_front = new_front;
- new_front = front;
- front = tmp_front;
-
- tmp_front_size = new_front_size;
- new_front_size = front_size;
- front_size = tmp_front_size;
- } while(front_size > 0);
-}
-
-void Graph::find_best_paths(int *result_edge_occupation) {
- Vertex **front = new Vertex *[nb_vertices];
- Vertex **new_front = new Vertex *[nb_vertices];
-
- scalar_t total_length;
-
- initialize_work_lengths();
-
- do {
- total_length = 0.0;
- find_shortest_path(front, new_front);
- update_work_length();
-
- // Do we reach the sink?
- if(sink->pred_edge) {
-
- // 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;
- }
-
- // If that length is negative
- if(total_length < 0.0) {
- // Invert all the edges along the best path
- for(Vertex *v = sink; v->pred_edge; v = v->pred_vertex) {
- Edge *e = v->pred_edge;
- e->terminal_vertex = v->pred_vertex;
- e->occupied = 1 - e->occupied;
- e->length = - e->length;
- e->work_length = - e->work_length;
- v->pred_vertex->del_edge(e);
- v->add_edge(e);
- }
- }
- }
- } while(total_length < 0.0);
-
- delete[] front;
- delete[] new_front;
-
- for(int n = 0; n < nb_vertices; n++) {
- Vertex *v = &vertices[n];
- for(Edge *e = v->root_edge; e; e = e->next) {
- result_edge_occupation[e->id] = e->occupied;
- }
- }
-}
+//////////////////////////////////////////////////////////////////////
void find_best_paths(int nb_vertices,
int nb_edges, int *ea, int *eb, scalar_t *el,
int source, int sink,
int *result_edge_occupation) {
- Graph graph(nb_vertices, nb_edges, ea, eb, el, source, sink);
- graph.find_best_paths(result_edge_occupation);
+ MTPGraph graph(nb_vertices, nb_edges, ea, eb, source, sink);
+ graph.find_best_paths(el, result_edge_occupation);
}
void dot_print(int nb_vertices,
projects / mtp.git / blobdiff