property_put
Assigns a fixed constant value to a property map entry when an event occurs. Useful for initialization or for marking specific edges (e.g. back edges).
Defined in: <boost/graph/visitors.hpp>
Models: EventVisitor
Typical event: any
Example
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <boost/graph/visitors.hpp>
#include <boost/property_map/property_map.hpp>
#include <iostream>
#include <vector>
int main() {
using namespace boost;
using Graph = adjacency_list<vecS, vecS, directedS,
no_property, property<edge_index_t, int>>;
using Edge = graph_traits<Graph>::edge_descriptor;
Graph g(4);
add_edge(0, 1, 0, g);
add_edge(1, 2, 1, g);
add_edge(2, 0, 2, g); // creates a back edge
add_edge(1, 3, 3, g);
// Mark back edges with true using property_put
std::vector<bool> is_back(num_edges(g), false);
auto edge_id = get(edge_index, g);
auto back_map = make_iterator_property_map(is_back.begin(), edge_id);
auto vis = make_dfs_visitor(
put_property(back_map, true, on_back_edge())
);
depth_first_search(g, visitor(vis));
for (auto ei = edges(g).first; ei != edges(g).second; ++ei) {
Edge e = *ei;
std::cout << source(e, g) << " -> " << target(e, g);
if (is_back[get(edge_id, e)]) {
std::cout << " [back edge]";
}
std::cout << "\n";
}
}0 -> 1
1 -> 2
1 -> 3
2 -> 0 [back edge]Synopsis
template <typename PropertyMap, typename EventTag>
struct property_put;
template <typename PropertyMap, typename EventTag>
property_put<PropertyMap, EventTag>
put_property(PropertyMap pa,
typename property_traits<PropertyMap>::value_type val,
EventTag);