edge_list<EdgeIterator, ValueType, DiffType>
The edge_list class is an adaptor that turns a pair of edge iterators into a class that models EdgeListGraph. The value_type of the edge iterator must be a std::pair (or at least have first and second members). The first_type and second_type of the pair must be the same and they will be used for the graph's vertex_descriptor. The ValueType and DiffType template parameters are only needed if your compiler does not support partial specialization. Otherwise they default to the correct types.
Applying the Bellman-Ford shortest paths algorithm to an edge_list.
enum { u, v, x, y, z, N };
char name[] = { 'u', 'v', 'x', 'y', 'z' };
typedef std::pair<int,int> E;
E edges[] = { E(u,y), E(u,x), E(u,v),
E(v,u),
E(x,y), E(x,v),
E(y,v), E(y,z),
E(z,u), E(z,x) };
int weight[] = { -4, 8, 5,
-2,
9, -3,
7, 2,
6, 7 };
typedef boost::edge_list<E*> Graph;
Graph g(edges, edges + sizeof(edges) / sizeof(E));
std::vector<int> distance(N, std::numeric_limits<short>::max());
std::vector<int> parent(N,-1);
distance[z] = 0;
parent[z] = z;
bool r = boost::bellman_ford_shortest_paths(g, int(N), weight,
distance.begin(),
parent.begin());
if (r)
for (int i = 0; i < N; ++i)
std::cout << name[i] << ": " << distance[i]
<< " " << name[parent[i]] << std::endl;
else
std::cout << "negative cycle" << std::endl;
The output is the distance from the root and the parent
of each vertex in the shortest paths tree.
u: 2 v v: 4 x x: 7 z y: -2 u z: 0 z
| Parameter | Description |
|---|---|
| EdgeIterator | Must be model of InputIterator who's value_type must be a pair of vertex descriptors. |
| ValueType | The value_type of the EdgeIterator. Default: std::iterator_traits<EdgeIterator>::value_type |
| DiffType | The difference_type of the EdgeIterator. Default: std::iterator_traits<EdgeIterator>::difference_type |
| Copyright © 2000-2001 |
Jeremy Siek,
Indiana University (jsiek@osl.iu.edu) Lie-Quan Lee, Indiana University (llee@cs.indiana.edu) Andrew Lumsdaine, Indiana University (lums@osl.iu.edu) |