boost/libs/graph/example/astar-cities.cpp
2021-10-05 21:37:46 +02:00

238 lines
7.1 KiB
C++

//
//=======================================================================
// Copyright (c) 2004 Kristopher Beevers
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
//
#include <boost/graph/astar_search.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/random.hpp>
#include <boost/random.hpp>
#include <boost/graph/graphviz.hpp>
#include <ctime>
#include <vector>
#include <list>
#include <iostream>
#include <fstream>
#include <math.h> // for sqrt
using namespace boost;
using namespace std;
// auxiliary types
struct location
{
float y, x; // lat, long
};
typedef float cost;
template < class Name, class LocMap > class city_writer
{
public:
city_writer(Name n, LocMap l, float _minx, float _maxx, float _miny,
float _maxy, unsigned int _ptx, unsigned int _pty)
: name(n)
, loc(l)
, minx(_minx)
, maxx(_maxx)
, miny(_miny)
, maxy(_maxy)
, ptx(_ptx)
, pty(_pty)
{
}
template < class Vertex >
void operator()(ostream& out, const Vertex& v) const
{
float px = 1 - (loc[v].x - minx) / (maxx - minx);
float py = (loc[v].y - miny) / (maxy - miny);
out << "[label=\"" << name[v] << "\", pos=\""
<< static_cast< unsigned int >(ptx * px) << ","
<< static_cast< unsigned int >(pty * py) << "\", fontsize=\"11\"]";
}
private:
Name name;
LocMap loc;
float minx, maxx, miny, maxy;
unsigned int ptx, pty;
};
template < class WeightMap > class time_writer
{
public:
time_writer(WeightMap w) : wm(w) {}
template < class Edge > void operator()(ostream& out, const Edge& e) const
{
out << "[label=\"" << wm[e] << "\", fontsize=\"11\"]";
}
private:
WeightMap wm;
};
// euclidean distance heuristic
template < class Graph, class CostType, class LocMap >
class distance_heuristic : public astar_heuristic< Graph, CostType >
{
public:
typedef typename graph_traits< Graph >::vertex_descriptor Vertex;
distance_heuristic(LocMap l, Vertex goal) : m_location(l), m_goal(goal) {}
CostType operator()(Vertex u)
{
CostType dx = m_location[m_goal].x - m_location[u].x;
CostType dy = m_location[m_goal].y - m_location[u].y;
return ::sqrt(dx * dx + dy * dy);
}
private:
LocMap m_location;
Vertex m_goal;
};
struct found_goal
{
}; // exception for termination
// visitor that terminates when we find the goal
template < class Vertex >
class astar_goal_visitor : public boost::default_astar_visitor
{
public:
astar_goal_visitor(Vertex goal) : m_goal(goal) {}
template < class Graph > void examine_vertex(Vertex u, Graph& g)
{
if (u == m_goal)
throw found_goal();
}
private:
Vertex m_goal;
};
int main(int argc, char** argv)
{
// specify some types
typedef adjacency_list< listS, vecS, undirectedS, no_property,
property< edge_weight_t, cost > >
mygraph_t;
typedef property_map< mygraph_t, edge_weight_t >::type WeightMap;
typedef mygraph_t::vertex_descriptor vertex;
typedef mygraph_t::edge_descriptor edge_descriptor;
typedef std::pair< int, int > edge;
// specify data
enum nodes
{
Troy,
LakePlacid,
Plattsburgh,
Massena,
Watertown,
Utica,
Syracuse,
Rochester,
Buffalo,
Ithaca,
Binghamton,
Woodstock,
NewYork,
N
};
const char* name[] = { "Troy", "Lake Placid", "Plattsburgh", "Massena",
"Watertown", "Utica", "Syracuse", "Rochester", "Buffalo", "Ithaca",
"Binghamton", "Woodstock", "New York" };
location locations[] = { // lat/long
{ 42.73, 73.68 }, { 44.28, 73.99 }, { 44.70, 73.46 }, { 44.93, 74.89 },
{ 43.97, 75.91 }, { 43.10, 75.23 }, { 43.04, 76.14 }, { 43.17, 77.61 },
{ 42.89, 78.86 }, { 42.44, 76.50 }, { 42.10, 75.91 }, { 42.04, 74.11 },
{ 40.67, 73.94 }
};
edge edge_array[]
= { edge(Troy, Utica), edge(Troy, LakePlacid), edge(Troy, Plattsburgh),
edge(LakePlacid, Plattsburgh), edge(Plattsburgh, Massena),
edge(LakePlacid, Massena), edge(Massena, Watertown),
edge(Watertown, Utica), edge(Watertown, Syracuse),
edge(Utica, Syracuse), edge(Syracuse, Rochester),
edge(Rochester, Buffalo), edge(Syracuse, Ithaca),
edge(Ithaca, Binghamton), edge(Ithaca, Rochester),
edge(Binghamton, Troy), edge(Binghamton, Woodstock),
edge(Binghamton, NewYork), edge(Syracuse, Binghamton),
edge(Woodstock, Troy), edge(Woodstock, NewYork) };
unsigned int num_edges = sizeof(edge_array) / sizeof(edge);
cost weights[] = { // estimated travel time (mins)
96, 134, 143, 65, 115, 133, 117, 116, 74, 56, 84, 73, 69, 70, 116, 147,
173, 183, 74, 71, 124
};
// create graph
mygraph_t g(N);
WeightMap weightmap = get(edge_weight, g);
for (std::size_t j = 0; j < num_edges; ++j)
{
edge_descriptor e;
bool inserted;
boost::tie(e, inserted)
= add_edge(edge_array[j].first, edge_array[j].second, g);
weightmap[e] = weights[j];
}
// pick random start/goal
boost::mt19937 gen(std::time(0));
vertex start = random_vertex(g, gen);
vertex goal = random_vertex(g, gen);
cout << "Start vertex: " << name[start] << endl;
cout << "Goal vertex: " << name[goal] << endl;
ofstream dotfile;
dotfile.open("test-astar-cities.dot");
write_graphviz(dotfile, g,
city_writer< const char**, location* >(
name, locations, 73.46, 78.86, 40.67, 44.93, 480, 400),
time_writer< WeightMap >(weightmap));
vector< mygraph_t::vertex_descriptor > p(num_vertices(g));
vector< cost > d(num_vertices(g));
try
{
// call astar named parameter interface
astar_search_tree(g, start,
distance_heuristic< mygraph_t, cost, location* >(locations, goal),
predecessor_map(
make_iterator_property_map(p.begin(), get(vertex_index, g)))
.distance_map(
make_iterator_property_map(d.begin(), get(vertex_index, g)))
.visitor(astar_goal_visitor< vertex >(goal)));
}
catch (found_goal fg)
{ // found a path to the goal
list< vertex > shortest_path;
for (vertex v = goal;; v = p[v])
{
shortest_path.push_front(v);
if (p[v] == v)
break;
}
cout << "Shortest path from " << name[start] << " to " << name[goal]
<< ": ";
list< vertex >::iterator spi = shortest_path.begin();
cout << name[start];
for (++spi; spi != shortest_path.end(); ++spi)
cout << " -> " << name[*spi];
cout << endl << "Total travel time: " << d[goal] << endl;
return 0;
}
cout << "Didn't find a path from " << name[start] << "to" << name[goal]
<< "!" << endl;
return 0;
}