diff -r 666f914201fb -r 2fe1408b6811 epoc32/include/stdapis/boost/graph/edge_connectivity.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/epoc32/include/stdapis/boost/graph/edge_connectivity.hpp Tue Mar 16 16:12:26 2010 +0000 @@ -0,0 +1,181 @@ +//======================================================================= +// Copyright 2000 University of Notre Dame. +// Authors: Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee +// +// 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) +//======================================================================= + +#ifndef BOOST_EDGE_CONNECTIVITY +#define BOOST_EDGE_CONNECTIVITY + +// WARNING: not-yet fully tested! + +#include +#include +#include +#include +#include + +namespace boost { + + namespace detail { + + template + inline + std::pair::vertex_descriptor, + typename graph_traits::degree_size_type> + min_degree_vertex(Graph& g) + { + typedef graph_traits Traits; + typename Traits::vertex_descriptor p; + typedef typename Traits::degree_size_type size_type; + size_type delta = (std::numeric_limits::max)(); + + typename Traits::vertex_iterator i, iend; + for (tie(i, iend) = vertices(g); i != iend; ++i) + if (degree(*i, g) < delta) { + delta = degree(*i, g); + p = *i; + } + return std::make_pair(p, delta); + } + + template + void neighbors(const Graph& g, + typename graph_traits::vertex_descriptor u, + OutputIterator result) + { + typename graph_traits::adjacency_iterator ai, aend; + for (tie(ai, aend) = adjacent_vertices(u, g); ai != aend; ++ai) + *result++ = *ai; + } + + template + void neighbors(const Graph& g, + VertexIterator first, VertexIterator last, + OutputIterator result) + { + for (; first != last; ++first) + neighbors(g, *first, result); + } + + } // namespace detail + + // O(m n) + template + typename graph_traits::degree_size_type + edge_connectivity(VertexListGraph& g, OutputIterator disconnecting_set) + { + //------------------------------------------------------------------------- + // Type Definitions + typedef graph_traits Traits; + typedef typename Traits::vertex_iterator vertex_iterator; + typedef typename Traits::edge_iterator edge_iterator; + typedef typename Traits::out_edge_iterator out_edge_iterator; + typedef typename Traits::vertex_descriptor vertex_descriptor; + typedef typename Traits::degree_size_type degree_size_type; + typedef color_traits Color; + + typedef adjacency_list_traits Tr; + typedef typename Tr::edge_descriptor Tr_edge_desc; + typedef adjacency_list > > > + FlowGraph; + typedef typename graph_traits::edge_descriptor edge_descriptor; + + //------------------------------------------------------------------------- + // Variable Declarations + vertex_descriptor u, v, p, k; + edge_descriptor e1, e2; + bool inserted; + vertex_iterator vi, vi_end; + edge_iterator ei, ei_end; + degree_size_type delta, alpha_star, alpha_S_k; + std::set S, neighbor_S; + std::vector S_star, non_neighbor_S; + std::vector color(num_vertices(g)); + std::vector pred(num_vertices(g)); + + //------------------------------------------------------------------------- + // Create a network flow graph out of the undirected graph + FlowGraph flow_g(num_vertices(g)); + + typename property_map::type + cap = get(edge_capacity, flow_g); + typename property_map::type + res_cap = get(edge_residual_capacity, flow_g); + typename property_map::type + rev_edge = get(edge_reverse, flow_g); + + for (tie(ei, ei_end) = edges(g); ei != ei_end; ++ei) { + u = source(*ei, g), v = target(*ei, g); + tie(e1, inserted) = add_edge(u, v, flow_g); + cap[e1] = 1; + tie(e2, inserted) = add_edge(v, u, flow_g); + cap[e2] = 1; // not sure about this + rev_edge[e1] = e2; + rev_edge[e2] = e1; + } + + //------------------------------------------------------------------------- + // The Algorithm + + tie(p, delta) = detail::min_degree_vertex(g); + S_star.push_back(p); + alpha_star = delta; + S.insert(p); + neighbor_S.insert(p); + detail::neighbors(g, S.begin(), S.end(), + std::inserter(neighbor_S, neighbor_S.begin())); + + std::set_difference(vertices(g).first, vertices(g).second, + neighbor_S.begin(), neighbor_S.end(), + std::back_inserter(non_neighbor_S)); + + while (!non_neighbor_S.empty()) { // at most n - 1 times + k = non_neighbor_S.front(); + + alpha_S_k = edmunds_karp_max_flow + (flow_g, p, k, cap, res_cap, rev_edge, &color[0], &pred[0]); + + if (alpha_S_k < alpha_star) { + alpha_star = alpha_S_k; + S_star.clear(); + for (tie(vi, vi_end) = vertices(flow_g); vi != vi_end; ++vi) + if (color[*vi] != Color::white()) + S_star.push_back(*vi); + } + S.insert(k); + neighbor_S.insert(k); + detail::neighbors(g, k, std::inserter(neighbor_S, neighbor_S.begin())); + non_neighbor_S.clear(); + std::set_difference(vertices(g).first, vertices(g).second, + neighbor_S.begin(), neighbor_S.end(), + std::back_inserter(non_neighbor_S)); + } + //------------------------------------------------------------------------- + // Compute edges of the cut [S*, ~S*] + std::vector in_S_star(num_vertices(g), false); + typename std::vector::iterator si; + for (si = S_star.begin(); si != S_star.end(); ++si) + in_S_star[*si] = true; + + degree_size_type c = 0; + for (si = S_star.begin(); si != S_star.end(); ++si) { + out_edge_iterator ei, ei_end; + for (tie(ei, ei_end) = out_edges(*si, g); ei != ei_end; ++ei) + if (!in_S_star[target(*ei, g)]) { + *disconnecting_set++ = *ei; + ++c; + } + } + return c; + } + +} // namespace boost + +#endif // BOOST_EDGE_CONNECTIVITY