template<typename RandomGenerator, typename Graph> class small_world_iterator { public: typedef std::input_iterator_tag iterator_category; typedef std::pair<vertices_size_type, vertices_size_type> value_type; typedef const value_type& reference; typedef const value_type* pointer; typedef void difference_type; small_world_iterator(); small_world_iterator(RandomGenerator& gen, vertices_size_type n, vertices_size_type k, double probability, bool allow_self_loops = false); // Iterator operations reference operator*() const; pointer operator->() const; small_world_iterator& operator++(); small_world_iterator operator++(int); bool operator==(const small_world_iterator& other) const; bool operator!=(const small_world_iterator& other) const; };
This class template implements a generator for small-world graphs, suitable for initializing an adjacency_list or other graph structure with iterator-based initialization. A small-world graph consists of a ring graph (where each vertex is connected to its k nearest neighbors). Edges in the graph are randomly rewired to different vertices with a probability p. Small-world graphs exhibit a high clustering coefficient (because vertices are always connected to their closest neighbors), but rewiring ensures a small diameter.
small_world_iterator();
Constructs a past-the-end iterator.
small_world_iterator(RandomGenerator& gen, vertices_size_type n, vertices_size_type k, double probability, bool allow_self_loops = false);
Constructs a small-world generator iterator that creates a graph with n vertices, each connected to its k nearest neighbors. Probabilities are drawn from the random number generator gen. Self-loops are permitted only when allow_self_loops is true.
#include <boost/graph/adjacency_list.hpp> #include <boost/graph/small_world_generator.hpp> #include <boost/random/linear_congruential.hpp> typedef boost::adjacency_list<> Graph; typedef boost::small_world_iterator<boost::minstd_rand, Graph> SWGen; int main() { boost::minstd_rand gen; // Create graph with 100 nodes Graph g(SWGen(gen, 100, 6, 0.03), SWGen(), 100); return 0; }
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Doug Gregor, Indiana University () Andrew Lumsdaine, Indiana University () |