Dear Boosters, I'm posting a non-recursive version of undirected_dfs, which should have advantages in space and time over the current implementation based on recursion, especially for huge graphs. It's a direct counterpart of the non-recursive version of depth_first_search for digraphs. I have confirmed that libs/graph/example/undirected_dfs.cpp as well as my own programs using undirected_dfs reproduce the identical outputs as those with the original recursive version. Best regards, Synge *** boost/graph/undirected_dfs.hpp 6 Aug 2004 05:02:41 -0000 1.1.1.1 --- boost/graph/undirected_dfs.hpp 19 Aug 2004 05:11:32 -0000 1.2 *************** *** 28,38 **** --- 28,106 ---- #define BOOST_GRAPH_UNDIRECTED_DFS_HPP #include <boost/graph/depth_first_search.hpp> + #include <vector> namespace boost { namespace detail { + // Define BOOST_RECURSIVE_DFS to use older, recursive version. + // It is retained for a while in order to perform performance + // comparison. + #ifndef BOOST_RECURSIVE_DFS + + template <typename IncidenceGraph, typename DFSVisitor, + typename VertexColorMap, typename EdgeColorMap> + void undir_dfv_impl + (const IncidenceGraph& g, + typename graph_traits<IncidenceGraph>::vertex_descriptor u, + DFSVisitor& vis, + VertexColorMap vertex_color, + EdgeColorMap edge_color) + { + function_requires<IncidenceGraphConcept<IncidenceGraph> >(); + function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >(); + typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex; + typedef typename graph_traits<IncidenceGraph>::edge_descriptor Edge; + function_requires<ReadWritePropertyMapConcept<VertexColorMap,Vertex> >(); + function_requires<ReadWritePropertyMapConcept<EdgeColorMap,Edge> >(); + typedef typename property_traits<VertexColorMap>::value_type ColorValue; + typedef typename property_traits<EdgeColorMap>::value_type EColorValue; + function_requires< ColorValueConcept<ColorValue> >(); + function_requires< ColorValueConcept<EColorValue> >(); + typedef color_traits<ColorValue> Color; + typedef color_traits<EColorValue> EColor; + typedef typename graph_traits<IncidenceGraph>::out_edge_iterator Iter; + typedef std::pair<Vertex, std::pair<Iter, Iter> > VertexInfo; + + std::vector<VertexInfo> stack; + + put(vertex_color, u, Color::gray()); + vis.discover_vertex(u, g); + stack.push_back(std::make_pair(u, out_edges(u, g))); + while (!stack.empty()) { + VertexInfo& back = stack.back(); + u = back.first; + Iter ei, ei_end; + tie(ei, ei_end) = back.second; + stack.pop_back(); + while (ei != ei_end) { + Vertex v = target(*ei, g); + vis.examine_edge(*ei, g); + ColorValue v_color = get(vertex_color, v); + EColorValue uv_color = get(edge_color, *ei); + put(edge_color, *ei, EColor::black()); + if (v_color == Color::white()) { + vis.tree_edge(*ei, g); + stack.push_back(std::make_pair(u, std::make_pair(++ei, ei_end))); + u = v; + put(vertex_color, u, Color::gray()); + vis.discover_vertex(u, g); + tie(ei, ei_end) = out_edges(u, g); + } else if (v_color == Color::gray()) { + if (uv_color == EColor::white()) vis.back_edge(*ei, g); + ++ei; + } else { // if (v_color == Color::black()) + ++ei; + } + } + put(vertex_color, u, Color::black()); + vis.finish_vertex(u, g); + } + } + + #else // BOOST_RECURSIVE_DFS + template <typename IncidenceGraph, typename DFSVisitor, typename VertexColorMap, typename EdgeColorMap> void undir_dfv_impl *************** *** 69,74 **** --- 137,145 ---- } put(vertex_color, u, Color::black()); vis.finish_vertex(u, g); } + + #endif // ! BOOST_RECURSIVE_DFS + } // namespace detail template <typename Graph, typename DFSVisitor,