williamr@2: // Copyright 2004 The Trustees of Indiana University. williamr@2: williamr@2: // Distributed under the Boost Software License, Version 1.0. williamr@2: // (See accompanying file LICENSE_1_0.txt or copy at williamr@2: // http://www.boost.org/LICENSE_1_0.txt) williamr@2: williamr@2: // Authors: Jeremiah Willcock williamr@2: // Douglas Gregor williamr@2: // Andrew Lumsdaine williamr@2: #ifndef BOOST_GRAPH_GURSOY_ATUN_LAYOUT_HPP williamr@2: #define BOOST_GRAPH_GURSOY_ATUN_LAYOUT_HPP williamr@2: williamr@2: // Gursoy-Atun graph layout, based on: williamr@2: // "Neighbourhood Preserving Load Balancing: A Self-Organizing Approach" williamr@2: // in EuroPar 2000, p. 234 of LNCS 1900 williamr@2: // http://springerlink.metapress.com/link.asp?id=pcu07ew5rhexp9yt williamr@2: williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: williamr@2: namespace boost { williamr@2: williamr@2: namespace detail { williamr@2: williamr@2: struct over_distance_limit : public std::exception {}; williamr@2: williamr@2: template williamr@2: struct update_position_visitor { williamr@2: typedef typename Topology::point_type Point; williamr@2: PositionMap position_map; williamr@2: NodeDistanceMap node_distance; williamr@2: const Topology& space; williamr@2: Point input_vector; williamr@2: double distance_limit; williamr@2: double learning_constant; williamr@2: double falloff_ratio; williamr@2: williamr@2: typedef boost::on_examine_vertex event_filter; williamr@2: williamr@2: typedef typename graph_traits::vertex_descriptor williamr@2: vertex_descriptor; williamr@2: williamr@2: update_position_visitor(PositionMap position_map, williamr@2: NodeDistanceMap node_distance, williamr@2: const Topology& space, williamr@2: const Point& input_vector, williamr@2: double distance_limit, williamr@2: double learning_constant, williamr@2: double falloff_ratio): williamr@2: position_map(position_map), node_distance(node_distance), williamr@2: space(space), williamr@2: input_vector(input_vector), distance_limit(distance_limit), williamr@2: learning_constant(learning_constant), falloff_ratio(falloff_ratio) {} williamr@2: williamr@2: void operator()(vertex_descriptor v, const Graph&) const williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::pow; williamr@2: #endif williamr@2: williamr@2: if (get(node_distance, v) > distance_limit) williamr@2: throw over_distance_limit(); williamr@2: Point old_position = get(position_map, v); williamr@2: double distance = get(node_distance, v); williamr@2: double fraction = williamr@2: learning_constant * pow(falloff_ratio, distance * distance); williamr@2: put(position_map, v, williamr@2: space.move_position_toward(old_position, fraction, input_vector)); williamr@2: } williamr@2: }; williamr@2: williamr@2: template williamr@2: struct gursoy_shortest williamr@2: { williamr@2: template williamr@2: static inline void williamr@2: run(const Graph& g, typename graph_traits::vertex_descriptor s, williamr@2: NodeDistanceMap node_distance, UpdatePosition& update_position, williamr@2: EdgeWeightMap weight) williamr@2: { williamr@2: boost::dijkstra_shortest_paths(g, s, weight_map(weight). williamr@2: visitor(boost::make_dijkstra_visitor(std::make_pair( williamr@2: boost::record_distances(node_distance, boost::on_edge_relaxed()), williamr@2: update_position)))); williamr@2: } williamr@2: }; williamr@2: williamr@2: template<> williamr@2: struct gursoy_shortest williamr@2: { williamr@2: template williamr@2: static inline void williamr@2: run(const Graph& g, typename graph_traits::vertex_descriptor s, williamr@2: NodeDistanceMap node_distance, UpdatePosition& update_position, williamr@2: dummy_property_map) williamr@2: { williamr@2: boost::breadth_first_search(g, s, williamr@2: visitor(boost::make_bfs_visitor(std::make_pair( williamr@2: boost::record_distances(node_distance, boost::on_tree_edge()), williamr@2: update_position)))); williamr@2: } williamr@2: }; williamr@2: williamr@2: } // namespace detail williamr@2: williamr@2: template williamr@2: void williamr@2: gursoy_atun_step williamr@2: (const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position, williamr@2: Diameter diameter, williamr@2: double learning_constant, williamr@2: VertexIndexMap vertex_index_map, williamr@2: EdgeWeightMap weight) williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::pow; williamr@2: using std::exp; williamr@2: #endif williamr@2: williamr@2: typedef typename graph_traits::vertex_iterator williamr@2: vertex_iterator; williamr@2: typedef typename graph_traits::vertex_descriptor williamr@2: vertex_descriptor; williamr@2: typedef typename Topology::point_type point_type; williamr@2: vertex_iterator i, iend; williamr@2: std::vector distance_from_input_vector(num_vertices(graph)); williamr@2: typedef boost::iterator_property_map::iterator, williamr@2: VertexIndexMap, williamr@2: double, double&> williamr@2: DistanceFromInputMap; williamr@2: DistanceFromInputMap distance_from_input(distance_from_input_vector.begin(), williamr@2: vertex_index_map); williamr@2: std::vector node_distance_map_vector(num_vertices(graph)); williamr@2: typedef boost::iterator_property_map::iterator, williamr@2: VertexIndexMap, williamr@2: double, double&> williamr@2: NodeDistanceMap; williamr@2: NodeDistanceMap node_distance(node_distance_map_vector.begin(), williamr@2: vertex_index_map); williamr@2: point_type input_vector = space.random_point(); williamr@2: vertex_descriptor min_distance_loc williamr@2: = graph_traits::null_vertex(); williamr@2: double min_distance = 0.0; williamr@2: bool min_distance_unset = true; williamr@2: for (boost::tie(i, iend) = vertices(graph); i != iend; ++i) { williamr@2: double this_distance = space.distance(get(position, *i), input_vector); williamr@2: put(distance_from_input, *i, this_distance); williamr@2: if (min_distance_unset || this_distance < min_distance) { williamr@2: min_distance = this_distance; williamr@2: min_distance_loc = *i; williamr@2: } williamr@2: min_distance_unset = false; williamr@2: } williamr@2: assert (!min_distance_unset); // Graph must have at least one vertex williamr@2: boost::detail::update_position_visitor< williamr@2: PositionMap, NodeDistanceMap, Topology, williamr@2: VertexListAndIncidenceGraph> williamr@2: update_position(position, node_distance, space, williamr@2: input_vector, diameter, learning_constant, williamr@2: exp(-1. / (2 * diameter * diameter))); williamr@2: std::fill(node_distance_map_vector.begin(), node_distance_map_vector.end(), 0); williamr@2: try { williamr@2: typedef detail::gursoy_shortest shortest; williamr@2: shortest::run(graph, min_distance_loc, node_distance, update_position, williamr@2: weight); williamr@2: } catch (detail::over_distance_limit) { williamr@2: /* Thrown to break out of BFS or Dijkstra early */ williamr@2: } williamr@2: } williamr@2: williamr@2: template williamr@2: void gursoy_atun_refine(const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position, williamr@2: int nsteps, williamr@2: double diameter_initial, williamr@2: double diameter_final, williamr@2: double learning_constant_initial, williamr@2: double learning_constant_final, williamr@2: VertexIndexMap vertex_index_map, williamr@2: EdgeWeightMap weight) williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::pow; williamr@2: using std::exp; williamr@2: #endif williamr@2: williamr@2: typedef typename graph_traits::vertex_iterator williamr@2: vertex_iterator; williamr@2: typedef typename graph_traits::vertex_descriptor williamr@2: vertex_descriptor; williamr@2: typedef typename Topology::point_type point_type; williamr@2: vertex_iterator i, iend; williamr@2: double diameter_ratio = (double)diameter_final / diameter_initial; williamr@2: double learning_constant_ratio = williamr@2: learning_constant_final / learning_constant_initial; williamr@2: std::vector distance_from_input_vector(num_vertices(graph)); williamr@2: typedef boost::iterator_property_map::iterator, williamr@2: VertexIndexMap, williamr@2: double, double&> williamr@2: DistanceFromInputMap; williamr@2: DistanceFromInputMap distance_from_input(distance_from_input_vector.begin(), williamr@2: vertex_index_map); williamr@2: std::vector node_distance_map_vector(num_vertices(graph)); williamr@2: typedef boost::iterator_property_map::iterator, williamr@2: VertexIndexMap, double, double&> williamr@2: NodeDistanceMap; williamr@2: NodeDistanceMap node_distance(node_distance_map_vector.begin(), williamr@2: vertex_index_map); williamr@2: for (int round = 0; round < nsteps; ++round) { williamr@2: double part_done = (double)round / (nsteps - 1); williamr@2: int diameter = (int)(diameter_initial * pow(diameter_ratio, part_done)); williamr@2: double learning_constant = williamr@2: learning_constant_initial * pow(learning_constant_ratio, part_done); williamr@2: gursoy_atun_step(graph, space, position, diameter, learning_constant, williamr@2: vertex_index_map, weight); williamr@2: } williamr@2: } williamr@2: williamr@2: template williamr@2: void gursoy_atun_layout(const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position, williamr@2: int nsteps, williamr@2: double diameter_initial, williamr@2: double diameter_final, williamr@2: double learning_constant_initial, williamr@2: double learning_constant_final, williamr@2: VertexIndexMap vertex_index_map, williamr@2: EdgeWeightMap weight) williamr@2: { williamr@2: typedef typename graph_traits::vertex_iterator williamr@2: vertex_iterator; williamr@2: vertex_iterator i, iend; williamr@2: for (boost::tie(i, iend) = vertices(graph); i != iend; ++i) { williamr@2: put(position, *i, space.random_point()); williamr@2: } williamr@2: gursoy_atun_refine(graph, space, williamr@2: position, nsteps, williamr@2: diameter_initial, diameter_final, williamr@2: learning_constant_initial, learning_constant_final, williamr@2: vertex_index_map, weight); williamr@2: } williamr@2: williamr@2: template williamr@2: void gursoy_atun_layout(const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position, williamr@2: int nsteps, williamr@2: double diameter_initial, williamr@2: double diameter_final, williamr@2: double learning_constant_initial, williamr@2: double learning_constant_final, williamr@2: VertexIndexMap vertex_index_map) williamr@2: { williamr@2: gursoy_atun_layout(graph, space, position, nsteps, williamr@2: diameter_initial, diameter_final, williamr@2: learning_constant_initial, learning_constant_final, williamr@2: vertex_index_map, dummy_property_map()); williamr@2: } williamr@2: williamr@2: template williamr@2: void gursoy_atun_layout(const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position, williamr@2: int nsteps, williamr@2: double diameter_initial, williamr@2: double diameter_final = 1.0, williamr@2: double learning_constant_initial = 0.8, williamr@2: double learning_constant_final = 0.2) williamr@2: { williamr@2: gursoy_atun_layout(graph, space, position, nsteps, diameter_initial, williamr@2: diameter_final, learning_constant_initial, williamr@2: learning_constant_final, get(vertex_index, graph)); williamr@2: } williamr@2: williamr@2: template williamr@2: void gursoy_atun_layout(const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position, williamr@2: int nsteps) williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::sqrt; williamr@2: #endif williamr@2: williamr@2: gursoy_atun_layout(graph, space, position, nsteps, williamr@2: sqrt((double)num_vertices(graph))); williamr@2: } williamr@2: williamr@2: template williamr@2: void gursoy_atun_layout(const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position) williamr@2: { williamr@2: gursoy_atun_layout(graph, space, position, num_vertices(graph)); williamr@2: } williamr@2: williamr@2: template williamr@2: void williamr@2: gursoy_atun_layout(const VertexListAndIncidenceGraph& graph, williamr@2: const Topology& space, williamr@2: PositionMap position, williamr@2: const bgl_named_params& params) williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::sqrt; williamr@2: #endif williamr@2: williamr@2: std::pair diam(sqrt(double(num_vertices(graph))), 1.0); williamr@2: std::pair learn(0.8, 0.2); williamr@2: gursoy_atun_layout(graph, space, position, williamr@2: choose_param(get_param(params, iterations_t()), williamr@2: num_vertices(graph)), williamr@2: choose_param(get_param(params, diameter_range_t()), williamr@2: diam).first, williamr@2: choose_param(get_param(params, diameter_range_t()), williamr@2: diam).second, williamr@2: choose_param(get_param(params, learning_constant_range_t()), williamr@2: learn).first, williamr@2: choose_param(get_param(params, learning_constant_range_t()), williamr@2: learn).second, williamr@2: choose_const_pmap(get_param(params, vertex_index), graph, williamr@2: vertex_index), williamr@2: choose_param(get_param(params, edge_weight), williamr@2: dummy_property_map())); williamr@2: } williamr@2: williamr@2: /*********************************************************** williamr@2: * Topologies * williamr@2: ***********************************************************/ williamr@2: template williamr@2: class convex_topology williamr@2: { williamr@2: struct point williamr@2: { williamr@2: point() { } williamr@2: double& operator[](std::size_t i) {return values[i];} williamr@2: const double& operator[](std::size_t i) const {return values[i];} williamr@2: williamr@2: private: williamr@2: double values[Dims]; williamr@2: }; williamr@2: williamr@2: public: williamr@2: typedef point point_type; williamr@2: williamr@2: double distance(point a, point b) const williamr@2: { williamr@2: double dist = 0; williamr@2: for (std::size_t i = 0; i < Dims; ++i) { williamr@2: double diff = b[i] - a[i]; williamr@2: dist += diff * diff; williamr@2: } williamr@2: // Exact properties of the distance are not important, as long as williamr@2: // < on what this returns matches real distances williamr@2: return dist; williamr@2: } williamr@2: williamr@2: point move_position_toward(point a, double fraction, point b) const williamr@2: { williamr@2: point result; williamr@2: for (std::size_t i = 0; i < Dims; ++i) williamr@2: result[i] = a[i] + (b[i] - a[i]) * fraction; williamr@2: return result; williamr@2: } williamr@2: }; williamr@2: williamr@2: template williamr@2: class hypercube_topology : public convex_topology williamr@2: { williamr@2: typedef uniform_01 rand_t; williamr@2: williamr@2: public: williamr@2: typedef typename convex_topology::point_type point_type; williamr@2: williamr@2: explicit hypercube_topology(double scaling = 1.0) williamr@2: : gen_ptr(new RandomNumberGenerator), rand(new rand_t(*gen_ptr)), williamr@2: scaling(scaling) williamr@2: { } williamr@2: williamr@2: hypercube_topology(RandomNumberGenerator& gen, double scaling = 1.0) williamr@2: : gen_ptr(), rand(new rand_t(gen)), scaling(scaling) { } williamr@2: williamr@2: point_type random_point() const williamr@2: { williamr@2: point_type p; williamr@2: for (std::size_t i = 0; i < Dims; ++i) williamr@2: p[i] = (*rand)() * scaling; williamr@2: return p; williamr@2: } williamr@2: williamr@2: private: williamr@2: shared_ptr gen_ptr; williamr@2: shared_ptr rand; williamr@2: double scaling; williamr@2: }; williamr@2: williamr@2: template williamr@2: class square_topology : public hypercube_topology<2, RandomNumberGenerator> williamr@2: { williamr@2: typedef hypercube_topology<2, RandomNumberGenerator> inherited; williamr@2: williamr@2: public: williamr@2: explicit square_topology(double scaling = 1.0) : inherited(scaling) { } williamr@2: williamr@2: square_topology(RandomNumberGenerator& gen, double scaling = 1.0) williamr@2: : inherited(gen, scaling) { } williamr@2: }; williamr@2: williamr@2: template williamr@2: class cube_topology : public hypercube_topology<3, RandomNumberGenerator> williamr@2: { williamr@2: typedef hypercube_topology<3, RandomNumberGenerator> inherited; williamr@2: williamr@2: public: williamr@2: explicit cube_topology(double scaling = 1.0) : inherited(scaling) { } williamr@2: williamr@2: cube_topology(RandomNumberGenerator& gen, double scaling = 1.0) williamr@2: : inherited(gen, scaling) { } williamr@2: }; williamr@2: williamr@2: template williamr@2: class ball_topology : public convex_topology williamr@2: { williamr@2: typedef uniform_01 rand_t; williamr@2: williamr@2: public: williamr@2: typedef typename convex_topology::point_type point_type; williamr@2: williamr@2: explicit ball_topology(double radius = 1.0) williamr@2: : gen_ptr(new RandomNumberGenerator), rand(new rand_t(*gen_ptr)), williamr@2: radius(radius) williamr@2: { } williamr@2: williamr@2: ball_topology(RandomNumberGenerator& gen, double radius = 1.0) williamr@2: : gen_ptr(), rand(new rand_t(gen)), radius(radius) { } williamr@2: williamr@2: point_type random_point() const williamr@2: { williamr@2: point_type p; williamr@2: double dist_sum; williamr@2: do { williamr@2: dist_sum = 0.0; williamr@2: for (std::size_t i = 0; i < Dims; ++i) { williamr@2: double x = (*rand)() * 2*radius - radius; williamr@2: p[i] = x; williamr@2: dist_sum += x * x; williamr@2: } williamr@2: } while (dist_sum > radius*radius); williamr@2: return p; williamr@2: } williamr@2: williamr@2: private: williamr@2: shared_ptr gen_ptr; williamr@2: shared_ptr rand; williamr@2: double radius; williamr@2: }; williamr@2: williamr@2: template williamr@2: class circle_topology : public ball_topology<2, RandomNumberGenerator> williamr@2: { williamr@2: typedef ball_topology<2, RandomNumberGenerator> inherited; williamr@2: williamr@2: public: williamr@2: explicit circle_topology(double radius = 1.0) : inherited(radius) { } williamr@2: williamr@2: circle_topology(RandomNumberGenerator& gen, double radius = 1.0) williamr@2: : inherited(gen, radius) { } williamr@2: }; williamr@2: williamr@2: template williamr@2: class sphere_topology : public ball_topology<3, RandomNumberGenerator> williamr@2: { williamr@2: typedef ball_topology<3, RandomNumberGenerator> inherited; williamr@2: williamr@2: public: williamr@2: explicit sphere_topology(double radius = 1.0) : inherited(radius) { } williamr@2: williamr@2: sphere_topology(RandomNumberGenerator& gen, double radius = 1.0) williamr@2: : inherited(gen, radius) { } williamr@2: }; williamr@2: williamr@2: template williamr@2: class heart_topology williamr@2: { williamr@2: // Heart is defined as the union of three shapes: williamr@2: // Square w/ corners (+-1000, -1000), (0, 0), (0, -2000) williamr@2: // Circle centered at (-500, -500) radius 500*sqrt(2) williamr@2: // Circle centered at (500, -500) radius 500*sqrt(2) williamr@2: // Bounding box (-1000, -2000) - (1000, 500*(sqrt(2) - 1)) williamr@2: williamr@2: struct point williamr@2: { williamr@2: point() { values[0] = 0.0; values[1] = 0.0; } williamr@2: point(double x, double y) { values[0] = x; values[1] = y; } williamr@2: williamr@2: double& operator[](std::size_t i) { return values[i]; } williamr@2: double operator[](std::size_t i) const { return values[i]; } williamr@2: williamr@2: private: williamr@2: double values[2]; williamr@2: }; williamr@2: williamr@2: bool in_heart(point p) const williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::abs; williamr@2: using std::pow; williamr@2: #endif williamr@2: williamr@2: if (p[1] < abs(p[0]) - 2000) return false; // Bottom williamr@2: if (p[1] <= -1000) return true; // Diagonal of square williamr@2: if (pow(p[0] - -500, 2) + pow(p[1] - -500, 2) <= 500000) williamr@2: return true; // Left circle williamr@2: if (pow(p[0] - 500, 2) + pow(p[1] - -500, 2) <= 500000) williamr@2: return true; // Right circle williamr@2: return false; williamr@2: } williamr@2: williamr@2: bool segment_within_heart(point p1, point p2) const williamr@2: { williamr@2: // Assumes that p1 and p2 are within the heart williamr@2: if ((p1[0] < 0) == (p2[0] < 0)) return true; // Same side of symmetry line williamr@2: if (p1[0] == p2[0]) return true; // Vertical williamr@2: double slope = (p2[1] - p1[1]) / (p2[0] - p1[0]); williamr@2: double intercept = p1[1] - p1[0] * slope; williamr@2: if (intercept > 0) return false; // Crosses between circles williamr@2: return true; williamr@2: } williamr@2: williamr@2: typedef uniform_01 rand_t; williamr@2: williamr@2: public: williamr@2: typedef point point_type; williamr@2: williamr@2: heart_topology() williamr@2: : gen_ptr(new RandomNumberGenerator), rand(new rand_t(*gen_ptr)) { } williamr@2: williamr@2: heart_topology(RandomNumberGenerator& gen) williamr@2: : gen_ptr(), rand(new rand_t(gen)) { } williamr@2: williamr@2: point random_point() const williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::sqrt; williamr@2: #endif williamr@2: williamr@2: point result; williamr@2: double sqrt2 = sqrt(2.); williamr@2: do { williamr@2: result[0] = (*rand)() * (1000 + 1000 * sqrt2) - (500 + 500 * sqrt2); williamr@2: result[1] = (*rand)() * (2000 + 500 * (sqrt2 - 1)) - 2000; williamr@2: } while (!in_heart(result)); williamr@2: return result; williamr@2: } williamr@2: williamr@2: double distance(point a, point b) const williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::sqrt; williamr@2: #endif williamr@2: if (segment_within_heart(a, b)) { williamr@2: // Straight line williamr@2: return sqrt((b[0] - a[0]) * (b[0] - a[0]) + (b[1] - a[1]) * (b[1] - a[1])); williamr@2: } else { williamr@2: // Straight line bending around (0, 0) williamr@2: return sqrt(a[0] * a[0] + a[1] * a[1]) + sqrt(b[0] * b[0] + b[1] * b[1]); williamr@2: } williamr@2: } williamr@2: williamr@2: point move_position_toward(point a, double fraction, point b) const williamr@2: { williamr@2: #ifndef BOOST_NO_STDC_NAMESPACE williamr@2: using std::sqrt; williamr@2: #endif williamr@2: williamr@2: if (segment_within_heart(a, b)) { williamr@2: // Straight line williamr@2: return point(a[0] + (b[0] - a[0]) * fraction, williamr@2: a[1] + (b[1] - a[1]) * fraction); williamr@2: } else { williamr@2: double distance_to_point_a = sqrt(a[0] * a[0] + a[1] * a[1]); williamr@2: double distance_to_point_b = sqrt(b[0] * b[0] + b[1] * b[1]); williamr@2: double location_of_point = distance_to_point_a / williamr@2: (distance_to_point_a + distance_to_point_b); williamr@2: if (fraction < location_of_point) williamr@2: return point(a[0] * (1 - fraction / location_of_point), williamr@2: a[1] * (1 - fraction / location_of_point)); williamr@2: else williamr@2: return point( williamr@2: b[0] * ((fraction - location_of_point) / (1 - location_of_point)), williamr@2: b[1] * ((fraction - location_of_point) / (1 - location_of_point))); williamr@2: } williamr@2: } williamr@2: williamr@2: private: williamr@2: shared_ptr gen_ptr; williamr@2: shared_ptr rand; williamr@2: }; williamr@2: williamr@2: } // namespace boost williamr@2: williamr@2: #endif // BOOST_GRAPH_GURSOY_ATUN_LAYOUT_HPP