generate ordering by breadth-first-search, a lot faster than before

release/4.3a0
Kai Ni 2010-01-08 04:12:23 +00:00
parent 8d22b3aca2
commit 215ff24d0f
1 changed files with 40 additions and 22 deletions

View File

@ -9,6 +9,8 @@
#include <boost/assign/std/list.hpp> // for operator +=
#include <boost/foreach.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/breadth_first_search.hpp>
#include "Ordering.h"
@ -18,40 +20,56 @@ using namespace boost::assign;
#define FOREACH_PAIR( KEY, VAL, COL) BOOST_FOREACH (boost::tie(KEY,VAL),COL)
class key_visitor : public boost::default_bfs_visitor {
public:
key_visitor(Ordering& ordering_in) : ordering_(ordering_in) {}
template <typename Vertex, typename Graph> void discover_vertex(Vertex u, const Graph& g) const {
string key = boost::get(boost::vertex_name, g, u);
ordering_.push_front(key);
}
Ordering& ordering_;
};
/* ************************************************************************* */
Ordering::Ordering(const map<string, string>& p_map) {
// find the root
string root;
bool foundRoot = false;
typedef boost::adjacency_list<
boost::vecS, boost::vecS, boost::undirectedS,
boost::property<boost::vertex_name_t, string> > Graph;
typedef boost::graph_traits<Graph>::vertex_descriptor Vertex;
// build the graph corresponding to the predecessor map
Graph g(0);
map<string, Vertex> key2vertex;
Vertex v1, v2, root;
string child, parent;
bool foundRoot = false;
FOREACH_PAIR(child, parent, p_map) {
if (key2vertex.find(child) == key2vertex.end()) {
v1 = add_vertex(child, g);
key2vertex.insert(make_pair(child, v1));
} else
v1 = key2vertex[child];
if (key2vertex.find(parent) == key2vertex.end()) {
v2 = add_vertex(parent, g);
key2vertex.insert(make_pair(parent, v2));
} else
v2 = key2vertex[parent];
if (child.compare(parent) == 0) {
root = child;
root = v1;
foundRoot = true;
break;
}
} else
boost::add_edge(v1, v2, g);
}
push_front(root);
if (!foundRoot)
throw invalid_argument("Ordering: invalid predecessor map!");
// push front the nodes from the root level to the leaf level
list<string> parents(1, root);
while(!parents.empty()){
list<string> children;
BOOST_FOREACH(string key, parents){
FOREACH_PAIR(child, parent, p_map){
if (parent.compare(key)==0 && child.compare(key)!=0) {
children.push_back(child);
push_front(child);
}
}
}
parents = children;
}
// breadth first visit on the graph
key_visitor vis(*this);
boost::breadth_first_search(g, root, boost::visitor(vis));
}
/* ************************************************************************* */