Vertex **c1, **c2, **h;
// omg, that's beautiful
h = heap_slot;
- while(c1 = heap + 2 * (h - heap + 1) - 1, c2 = c1 + 1,
- (c1 < heap + heap_size && (*c1)->distance_from_source < (*h)->distance_from_source)
- ||
- (c2 < heap + heap_size && (*c2)->distance_from_source < (*h)->distance_from_source)
- ) {
- if(c1 < heap + heap_size &&
- !(c2 < heap + heap_size && (*c2)->distance_from_source < (*c1)->distance_from_source)){
- swap(*c1, *h);
- swap((*c1)->heap_slot, (*h)->heap_slot);
- h = c1;
- } else {
+ while(c1 = heap + 2 * (h - heap) + 1,
+ c1 < heap + heap_size &&
+ (c2 = c1 + 1,
+ (*c1)->distance_from_source < (*h)->distance_from_source
+ ||
+ (c2 < heap + heap_size && (*c2)->distance_from_source < (*h)->distance_from_source)
+ )) {
+ if(c2 < heap + heap_size && (*c2)->distance_from_source <= (*c1)->distance_from_source) {
swap(*c2, *h);
swap((*c2)->heap_slot, (*h)->heap_slot);
h = c2;
+ } else {
+ swap(*c1, *h);
+ swap((*c1)->heap_slot, (*h)->heap_slot);
+ h = c1;
}
}
}
paths = 0;
nb_paths = 0;
- if(compute_dp_distances()) {
+ 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.
#endif
}
-int MTPGraph::compute_dp_distances() {
+int MTPGraph::compute_dp_ranks() {
Vertex *v;
Edge *e;
// removes the source, then the nodes with incoming edge only from
// the source, etc. If it can remove all the nodes that way, the
// graph is a DAG. If at some point it can not remove node anymore
- // and there are some remaining nodes, the graph is not a DAG.
+ // and there are some remaining nodes, the graph is not a DAG. The
+ // rank of a node is the iteration at which is it removed, and we
+ // set the distance_from_source fields to this value.
Vertex **active = new Vertex *[_nb_vertices];
active[k] = &_vertices[k];
}
- scalar_t nb_iterations = 1;
+ scalar_t rank = 1;
int nb_active = _nb_vertices, pred_nb_active;
do {
// We set the distance_from_source field of all the vertices with incoming
- // edges to the current nb_iterations value
+ // edges to the current rank value
for(int f = 0; f < nb_active; f++) {
v = active[f];
for(e = v->leaving_edges; e; e = e->next_leaving_edge) {
- e->terminal_vertex->distance_from_source = nb_iterations;
+ e->terminal_vertex->distance_from_source = rank;
}
}
// We keep all the vertices with incoming nodes
for(int f = 0; f < pred_nb_active; f++) {
v = active[f];
- if(v->distance_from_source == nb_iterations) {
+ if(v->distance_from_source == rank) {
active[nb_active++] = v;
}
}
- nb_iterations++;
+ rank++;
} while(nb_active < pred_nb_active);
delete[] active;