#include <iostream>
#include <float.h>
+#include <stdlib.h>
using namespace std;
class Edge {
public:
int id, occupied;
- scalar_t length, work_length;
+ scalar_t length, positivized_length;
Vertex *origin_vertex, *terminal_vertex;
// These are the links in the origin_vertex leaving edge list
- Edge *next, *pred;
+ Edge *next_leaving_edge, *pred_leaving_edge;
inline void revert();
};
class Vertex {
public:
- int id, iteration;
- Edge *root_edge;
+ int id;
+ Edge *leaving_edges;
scalar_t distance_from_source;
Edge *best_pred_edge_to_source;
+ int iteration; // Used in find_shortest_path to know if we already
+ // added this vertex to the front
Vertex();
inline void add_edge(Edge *e);
inline void del_edge(Edge *e);
void Edge::revert() {
length = - length;
- work_length = 0;
+ positivized_length = 0;
origin_vertex->del_edge(this);
terminal_vertex->add_edge(this);
Vertex *t = terminal_vertex;
//////////////////////////////////////////////////////////////////////
Vertex::Vertex() {
- root_edge = 0;
+ leaving_edges = 0;
}
void Vertex::add_edge(Edge *e) {
- e->next = root_edge;
- e->pred = 0;
- if(root_edge) { root_edge->pred = e; }
- root_edge = e;
+ e->next_leaving_edge = leaving_edges;
+ e->pred_leaving_edge = 0;
+ if(leaving_edges) { leaving_edges->pred_leaving_edge = e; }
+ leaving_edges = e;
}
void Vertex::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; }
+ if(e == leaving_edges) { leaving_edges = e->next_leaving_edge; }
+ if(e->pred_leaving_edge) { e->pred_leaving_edge->next_leaving_edge = e->next_leaving_edge; }
+ if(e->next_leaving_edge) { e->next_leaving_edge->pred_leaving_edge = e->pred_leaving_edge; }
}
//////////////////////////////////////////////////////////////////////
-void MTPGraph::print() {
- for(int k = 0; k < _nb_edges; k++) {
- Edge *e = _edges + k;
- cout << e->origin_vertex->id
- << " -> "
- << e->terminal_vertex->id
- << " "
- << e->length;
- if(e->occupied) {
- cout << " *";
- }
- cout << endl;
- }
+Path::Path(int l) {
+ length = l;
+ nodes = new int[length];
}
-void MTPGraph::print_dot() {
- cout << "digraph {" << endl;
- cout << " node[shape=circle];" << endl;
- for(int k = 0; k < _nb_edges; k++) {
- Edge *e = _edges + k;
- if(e->occupied) {
- cout << " " << e->origin_vertex->id << " -> " << e->terminal_vertex->id
- << " [style=bold,color=black,label=\"" << -e->length << "\"];" << endl;
- } else {
- cout << " " << e->origin_vertex->id << " -> " << e->terminal_vertex->id
- << " [color=gray,label=\"" << e->length << "\"];" << endl;
- }
- }
- cout << "}" << endl;
+Path::~Path() {
+ delete[] nodes;
}
+//////////////////////////////////////////////////////////////////////
+
MTPGraph::MTPGraph(int nb_vertices, int nb_edges,
int *from, int *to,
int source, int sink) {
_edges[e].terminal_vertex = _vertices + to[e];
}
+ paths = 0;
+ nb_paths = 0;
}
MTPGraph::~MTPGraph() {
delete[] _edges;
delete[] _front;
delete[] _new_front;
+ for(int p = 0; p < nb_paths; p++) delete paths[p];
+ delete[] paths;
+}
+
+//////////////////////////////////////////////////////////////////////
+
+void MTPGraph::print(ostream *os) {
+ for(int k = 0; k < _nb_edges; k++) {
+ Edge *e = _edges + k;
+ (*os) << e->origin_vertex->id
+ << " -> "
+ << e->terminal_vertex->id
+ << " "
+ << e->length;
+ if(e->occupied) {
+ (*os) << " *";
+ }
+ (*os) << endl;
+ }
+}
+
+void MTPGraph::print_dot(ostream *os) {
+ (*os) << "digraph {" << endl;
+ (*os) << " node[shape=circle];" << endl;
+ for(int k = 0; k < _nb_edges; k++) {
+ Edge *e = _edges + k;
+ // (*os) << " " << e->origin_vertex->id << " -> " << e->terminal_vertex->id
+ // << ";"
+ // << endl;
+ if(e->occupied) {
+ (*os) << " " << e->origin_vertex->id << " -> " << e->terminal_vertex->id
+ << " [style=bold,color=black,label=\"" << e->length << "\"];" << endl;
+ } else {
+ (*os) << " " << e->origin_vertex->id << " -> " << e->terminal_vertex->id
+ << " [color=gray,label=\"" << e->length << "\"];" << endl;
+ }
+ }
+ (*os) << "}" << endl;
}
-void MTPGraph::initialize_work_lengths_with_min() {
+//////////////////////////////////////////////////////////////////////
+
+void MTPGraph::initialize_positivized_lengths_with_min() {
scalar_t length_min = 0;
for(int n = 0; n < _nb_vertices; n++) {
- for(Edge *e = _vertices[n].root_edge; e; e = e->next) {
+ for(Edge *e = _vertices[n].leaving_edges; e; e = e->next_leaving_edge) {
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;
+ for(Edge *e = _vertices[n].leaving_edges; e; e = e->next_leaving_edge) {
+ e->positivized_length = e->length - length_min;
}
}
}
-void MTPGraph::update_work_lengths() {
+void MTPGraph::update_positivized_lengths() {
for(int k = 0; k < _nb_edges; k++) {
Edge *e = _edges + k;
- e->work_length += e->terminal_vertex->distance_from_source - e->terminal_vertex->distance_from_source;
+ e->positivized_length +=
+ e->origin_vertex->distance_from_source - e->terminal_vertex->distance_from_source;
}
}
-void MTPGraph::force_positive_work_lengths() {
+void MTPGraph::force_positivized_lengths() {
#ifdef VERBOSE
scalar_t residual_error = 0.0;
+ scalar_t max_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) {
+ for(Edge *e = _vertices[n].leaving_edges; e; e = e->next_leaving_edge) {
+ if(e->positivized_length < 0) {
#ifdef VERBOSE
- residual_error -= e->work_length;
+ residual_error -= e->positivized_length;
+ max_error = max(max_error, fabs(e->positivized_length));
#endif
- e->work_length = 0.0;
+ e->positivized_length = 0.0;
}
}
}
#ifdef VERBOSE
- cerr << "residual_error " << residual_error << endl;
+ cerr << "residual_error " << residual_error << " max_error " << residual_error << endl;
#endif
}
Vertex **tmp_front;
int tmp_front_size;
Vertex *v, *tv;
+ Edge *e;
scalar_t d;
for(int v = 0; v < _nb_vertices; v++) {
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;
+ for(e = v->leaving_edges; e; e = e->next_leaving_edge) {
+ d = v->distance_from_source + e->positivized_length;
tv = e->terminal_vertex;
if(d < tv->distance_from_source) {
tv->distance_from_source = d;
tmp_front_size = _new_front_size;
_new_front_size = _front_size;
_front_size = tmp_front_size;
+ cout << "_front_size = " << _front_size << endl;
} while(_front_size > 0);
}
-void MTPGraph::find_best_paths(scalar_t *lengths, int *result_edge_occupation) {
+void MTPGraph::find_best_paths(scalar_t *lengths) {
scalar_t total_length;
Vertex *v;
Edge *e;
for(int e = 0; e < _nb_edges; e++) {
_edges[e].length = lengths[e];
- _edges[e].work_length = _edges[e].length;
+ _edges[e].occupied = 0;
+ _edges[e].positivized_length = _edges[e].length;
}
// We use one iteration of find_shortest_path simply to propagate
// the distance to make all the edge lengths positive.
find_shortest_path(_front, _new_front);
- update_work_lengths();
+ update_positivized_lengths();
// #warning
- // initialize_work_lengths_with_min();
+ // initialize_positivized_lengths_with_min();
do {
- force_positive_work_lengths();
+ force_positivized_lengths();
find_shortest_path(_front, _new_front);
- update_work_lengths();
+ update_positivized_lengths();
total_length = 0.0;
// If that length is negative
if(total_length < 0.0) {
#ifdef VERBOSE
- cout << "Found a path of length " << total_length << endl;
+ cerr << "Found a path of length " << total_length << endl;
#endif
// Invert all the edges along the best path
v = _sink;
e = v->best_pred_edge_to_source;
v = e->origin_vertex;
e->revert();
+ // This is the only place where we change the occupations of
+ // edges
e->occupied = 1 - e->occupied;
}
}
for(int k = 0; k < _nb_edges; k++) {
Edge *e = _edges + k;
if(e->occupied) { e->revert(); }
- result_edge_occupation[k] = e->occupied;
+ }
+}
+
+int MTPGraph::retrieve_one_path(Edge *e, int *nodes) {
+ Edge *f, *next = 0;
+ int l = 0;
+
+ if(nodes) { nodes[l++] = e->origin_vertex->id; }
+ else l++;
+
+ while(e->terminal_vertex != _sink) {
+ if(nodes) { nodes[l++] = e->terminal_vertex->id; }
+ else l++;
+ int nb_choices = 0;
+ for(f = e->terminal_vertex->leaving_edges; f; f = f->next_leaving_edge) {
+ if(f->occupied) { nb_choices++; next = f; }
+ if(nb_choices == 0) {
+ cerr << "Non-sink path end point?!" << endl;
+ abort();
+ }
+ if(nb_choices > 1) {
+ cerr << "Non node-disjoint path, can not retrieve." << endl;
+ abort();
+ }
+ }
+ e = next;
+ }
+
+ if(nodes) { nodes[l++] = e->terminal_vertex->id; }
+ else l++;
+
+ return l;
+}
+
+void MTPGraph::retrieve_disjoint_paths() {
+ Edge *e;
+
+ for(int p = 0; p < nb_paths; p++) delete paths[p];
+ delete[] paths;
+
+ nb_paths = 0;
+ for(e = _source->leaving_edges; e; e = e->next_leaving_edge) {
+ if(e->occupied) { nb_paths++; }
+ }
+
+ paths = new Path *[nb_paths];
+
+ int p = 0;
+ for(e = _source->leaving_edges; e; e = e->next_leaving_edge) {
+ if(e->occupied) {
+ int l = retrieve_one_path(e, 0);
+ paths[p] = new Path(l);
+ retrieve_one_path(e, paths[p]->nodes);
+ p++;
+ }
}
}
projects / mtp.git / blobdiff