comparison DEPENDENCIES/generic/include/boost/graph/distributed/fruchterman_reingold.hpp @ 16:2665513ce2d3

Add boost headers

+// Copyright (C) 2005-2006 The Trustees of Indiana University.
+
+// Use, modification and distribution is subject to 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)
+
+//  Authors: Douglas Gregor
+//           Andrew Lumsdaine
+#ifndef BOOST_GRAPH_DISTRIBUTED_FRUCHTERMAN_REINGOLD_HPP
+#define BOOST_GRAPH_DISTRIBUTED_FRUCHTERMAN_REINGOLD_HPP
+
+#ifndef BOOST_GRAPH_USE_MPI
+#error "Parallel BGL files should not be included unless <boost/graph/use_mpi.hpp> has been included"
+#endif
+
+#include <boost/graph/fruchterman_reingold.hpp>
+
+namespace boost { namespace graph { namespace distributed {
+
+class simple_tiling
+{
+ public:
+  simple_tiling(int columns, int rows, bool flip = true) 
+    : columns(columns), rows(rows), flip(flip)
+  {
+  }
+
+  // Convert from a position (x, y) in the tiled display into a
+  // processor ID number
+  int operator()(int x, int y) const
+  {
+    return flip? (rows - y - 1) * columns + x : y * columns + x;
+  }
+
+  // Convert from a process ID to a position (x, y) in the tiled
+  // display
+  std::pair<int, int> operator()(int id)
+  {
+    int my_col = id % columns;
+    int my_row = flip? rows - (id / columns) - 1 : id / columns;
+    return std::make_pair(my_col, my_row);
+  }
+
+  int columns, rows;
+
+ private:
+  bool flip;
+};
+
+// Force pairs function object that does nothing
+struct no_force_pairs
+{
+  template<typename Graph, typename ApplyForce>
+  void operator()(const Graph&, const ApplyForce&)
+  {
+  }
+};
+
+// Computes force pairs in the distributed case.
+template<typename PositionMap, typename DisplacementMap, typename LocalForces,
+         typename NonLocalForces = no_force_pairs>
+class distributed_force_pairs_proxy
+{
+ public:
+  distributed_force_pairs_proxy(const PositionMap& position, 
+                                const DisplacementMap& displacement,
+                                const LocalForces& local_forces,
+                                const NonLocalForces& nonlocal_forces = NonLocalForces())
+    : position(position), displacement(displacement), 
+      local_forces(local_forces), nonlocal_forces(nonlocal_forces)
+  {
+  }
+
+  template<typename Graph, typename ApplyForce>
+  void operator()(const Graph& g, ApplyForce apply_force)
+  {
+    // Flush remote displacements
+    displacement.flush();
+
+    // Receive updated positions for all of our neighbors
+    synchronize(position);
+
+    // Reset remote displacements 
+    displacement.reset();
+
+    // Compute local repulsive forces
+    local_forces(g, apply_force);
+
+    // Compute neighbor repulsive forces
+    nonlocal_forces(g, apply_force);
+  }
+
+ protected:
+  PositionMap position;
+  DisplacementMap displacement;
+  LocalForces local_forces;
+  NonLocalForces nonlocal_forces;
+};
+
+template<typename PositionMap, typename DisplacementMap, typename LocalForces>
+inline 
+distributed_force_pairs_proxy<PositionMap, DisplacementMap, LocalForces>
+make_distributed_force_pairs(const PositionMap& position, 
+                             const DisplacementMap& displacement,
+                             const LocalForces& local_forces)
+{
+  typedef 
+    distributed_force_pairs_proxy<PositionMap, DisplacementMap, LocalForces>
+    result_type;
+  return result_type(position, displacement, local_forces);
+}
+
+template<typename PositionMap, typename DisplacementMap, typename LocalForces,
+         typename NonLocalForces>
+inline 
+distributed_force_pairs_proxy<PositionMap, DisplacementMap, LocalForces,
+                              NonLocalForces>
+make_distributed_force_pairs(const PositionMap& position, 
+                             const DisplacementMap& displacement,
+                             const LocalForces& local_forces,
+                             const NonLocalForces& nonlocal_forces)
+{
+  typedef 
+    distributed_force_pairs_proxy<PositionMap, DisplacementMap, LocalForces,
+                                  NonLocalForces>
+      result_type;
+  return result_type(position, displacement, local_forces, nonlocal_forces);
+}
+
+// Compute nonlocal force pairs based on the shared borders with
+// adjacent tiles.
+template<typename PositionMap>
+class neighboring_tiles_force_pairs
+{
+ public:
+  typedef typename property_traits<PositionMap>::value_type Point;
+  typedef typename point_traits<Point>::component_type Dim;
+
+  enum bucket_position { left, top, right, bottom, end_position };
+  
+  neighboring_tiles_force_pairs(PositionMap position, Point origin,
+                                Point extent, simple_tiling tiling)
+    : position(position), origin(origin), extent(extent), tiling(tiling)
+  {
+  }
+
+  template<typename Graph, typename ApplyForce>
+  void operator()(const Graph& g, ApplyForce apply_force)
+  {
+    // TBD: Do this some smarter way
+    if (tiling.columns == 1 && tiling.rows == 1)
+      return;
+
+    typedef typename graph_traits<Graph>::vertex_descriptor vertex_descriptor;
+#ifndef BOOST_NO_STDC_NAMESPACE
+    using std::sqrt;
+#endif // BOOST_NO_STDC_NAMESPACE
+
+    // TBD: num_vertices(g) should be the global number of vertices?
+    Dim two_k = Dim(2) * sqrt(extent[0] * extent[1] / num_vertices(g));
+
+    std::vector<vertex_descriptor> my_vertices[4];
+    std::vector<vertex_descriptor> neighbor_vertices[4];
+   
+    // Compute cutoff positions
+    Dim cutoffs[4];
+    cutoffs[left] = origin[0] + two_k;
+    cutoffs[top] = origin[1] + two_k;
+    cutoffs[right] = origin[0] + extent[0] - two_k;
+    cutoffs[bottom] = origin[1] + extent[1] - two_k;
+
+    // Compute neighbors
+    typename PositionMap::process_group_type pg = position.process_group();
+    std::pair<int, int> my_tile = tiling(process_id(pg));
+    int neighbors[4] = { -1, -1, -1, -1 } ;
+    if (my_tile.first > 0)
+      neighbors[left] = tiling(my_tile.first - 1, my_tile.second);
+    if (my_tile.second > 0)
+      neighbors[top] = tiling(my_tile.first, my_tile.second - 1);
+    if (my_tile.first < tiling.columns - 1)
+      neighbors[right] = tiling(my_tile.first + 1, my_tile.second);
+    if (my_tile.second < tiling.rows - 1)
+      neighbors[bottom] = tiling(my_tile.first, my_tile.second + 1);
+
+    // Sort vertices along the edges into buckets
+    BGL_FORALL_VERTICES_T(v, g, Graph) {
+      if (position[v][0] <= cutoffs[left]) my_vertices[left].push_back(v); 
+      if (position[v][1] <= cutoffs[top]) my_vertices[top].push_back(v); 
+      if (position[v][0] >= cutoffs[right]) my_vertices[right].push_back(v); 
+      if (position[v][1] >= cutoffs[bottom]) my_vertices[bottom].push_back(v); 
+    }
+
+    // Send vertices to neighbors, and gather our neighbors' vertices
+    bucket_position pos;
+    for (pos = left; pos < end_position; pos = bucket_position(pos + 1)) {
+      if (neighbors[pos] != -1) {
+        send(pg, neighbors[pos], 0, my_vertices[pos].size());
+        if (!my_vertices[pos].empty())
+          send(pg, neighbors[pos], 1, 
+               &my_vertices[pos].front(), my_vertices[pos].size());
+      }
+    }
+
+    // Pass messages around
+    synchronize(pg);
+    
+    // Receive neighboring vertices
+    for (pos = left; pos < end_position; pos = bucket_position(pos + 1)) {
+      if (neighbors[pos] != -1) {
+        std::size_t incoming_vertices;
+        receive(pg, neighbors[pos], 0, incoming_vertices);
+
+        if (incoming_vertices) {
+          neighbor_vertices[pos].resize(incoming_vertices);
+          receive(pg, neighbors[pos], 1, &neighbor_vertices[pos].front(),
+                  incoming_vertices);
+        }
+      }
+    }
+
+    // For each neighboring vertex, we need to get its current position
+    for (pos = left; pos < end_position; pos = bucket_position(pos + 1))
+      for (typename std::vector<vertex_descriptor>::iterator i = 
+             neighbor_vertices[pos].begin(); 
+           i != neighbor_vertices[pos].end();
+           ++i)
+        request(position, *i);
+    synchronize(position);
+
+    // Apply forces in adjacent bins. This is O(n^2) in the worst
+    // case. Oh well.
+    for (pos = left; pos < end_position; pos = bucket_position(pos + 1)) {
+      for (typename std::vector<vertex_descriptor>::iterator i = 
+             my_vertices[pos].begin(); 
+           i != my_vertices[pos].end();
+           ++i)
+        for (typename std::vector<vertex_descriptor>::iterator j = 
+               neighbor_vertices[pos].begin(); 
+             j != neighbor_vertices[pos].end();
+             ++j)
+          apply_force(*i, *j);
+    }
+  }
+
+ protected:
+  PositionMap position;
+  Point origin;
+  Point extent;
+  simple_tiling tiling;
+};
+
+template<typename PositionMap>
+inline neighboring_tiles_force_pairs<PositionMap>
+make_neighboring_tiles_force_pairs
+ (PositionMap position, 
+  typename property_traits<PositionMap>::value_type origin,
+  typename property_traits<PositionMap>::value_type extent,
+  simple_tiling tiling)
+{
+  return neighboring_tiles_force_pairs<PositionMap>(position, origin, extent,
+                                                    tiling);
+}
+
+template<typename DisplacementMap, typename Cooling>
+class distributed_cooling_proxy
+{
+ public:
+  typedef typename Cooling::result_type result_type;
+
+  distributed_cooling_proxy(const DisplacementMap& displacement,
+                            const Cooling& cooling)
+    : displacement(displacement), cooling(cooling)
+  {
+  }
+
+  result_type operator()()
+  {
+    // Accumulate displacements computed on each processor
+    synchronize(displacement.data->process_group);
+
+    // Allow the underlying cooling to occur
+    return cooling();
+  }
+
+ protected:
+  DisplacementMap displacement;
+  Cooling cooling;
+};
+
+template<typename DisplacementMap, typename Cooling>
+inline distributed_cooling_proxy<DisplacementMap, Cooling>
+make_distributed_cooling(const DisplacementMap& displacement,
+                         const Cooling& cooling)
+{
+  typedef distributed_cooling_proxy<DisplacementMap, Cooling> result_type;
+  return result_type(displacement, cooling);
+}
+
+template<typename Point>
+struct point_accumulating_reducer {
+  BOOST_STATIC_CONSTANT(bool, non_default_resolver = true);
+
+  template<typename K>
+  Point operator()(const K&) const { return Point(); }
+
+  template<typename K>
+  Point operator()(const K&, const Point& p1, const Point& p2) const 
+  { return Point(p1[0] + p2[0], p1[1] + p2[1]); }
+};
+
+template<typename Graph, typename PositionMap, 
+         typename AttractiveForce, typename RepulsiveForce,
+         typename ForcePairs, typename Cooling, typename DisplacementMap>
+void
+fruchterman_reingold_force_directed_layout
+ (const Graph&    g,
+  PositionMap     position,
+  typename property_traits<PositionMap>::value_type const& origin,
+  typename property_traits<PositionMap>::value_type const& extent,
+  AttractiveForce attractive_force,
+  RepulsiveForce  repulsive_force,
+  ForcePairs      force_pairs,
+  Cooling         cool,
+  DisplacementMap displacement)
+{
+  typedef typename property_traits<PositionMap>::value_type Point;
+
+  // Reduction in the displacement map involves summing the forces
+  displacement.set_reduce(point_accumulating_reducer<Point>());
+
+  // We need to track the positions of all of our neighbors
+  BGL_FORALL_VERTICES_T(u, g, Graph)
+    BGL_FORALL_ADJ_T(u, v, g, Graph)
+      request(position, v);
+
+  // Invoke the "sequential" Fruchterman-Reingold implementation
+  boost::fruchterman_reingold_force_directed_layout
+    (g, position, origin, extent,
+     attractive_force, repulsive_force,
+     make_distributed_force_pairs(position, displacement, force_pairs),
+     make_distributed_cooling(displacement, cool),
+     displacement);
+}
+
+template<typename Graph, typename PositionMap, 
+         typename AttractiveForce, typename RepulsiveForce,
+         typename ForcePairs, typename Cooling, typename DisplacementMap>
+void
+fruchterman_reingold_force_directed_layout
+ (const Graph&    g,
+  PositionMap     position,
+  typename property_traits<PositionMap>::value_type const& origin,
+  typename property_traits<PositionMap>::value_type const& extent,
+  AttractiveForce attractive_force,
+  RepulsiveForce  repulsive_force,
+  ForcePairs      force_pairs,
+  Cooling         cool,
+  DisplacementMap displacement,
+  simple_tiling   tiling)
+{
+  typedef typename property_traits<PositionMap>::value_type Point;
+
+  // Reduction in the displacement map involves summing the forces
+  displacement.set_reduce(point_accumulating_reducer<Point>());
+
+  // We need to track the positions of all of our neighbors
+  BGL_FORALL_VERTICES_T(u, g, Graph)
+    BGL_FORALL_ADJ_T(u, v, g, Graph)
+      request(position, v);
+
+  // Invoke the "sequential" Fruchterman-Reingold implementation
+  boost::fruchterman_reingold_force_directed_layout
+    (g, position, origin, extent,
+     attractive_force, repulsive_force,
+     make_distributed_force_pairs
+      (position, displacement, force_pairs,
+       make_neighboring_tiles_force_pairs(position, origin, extent, tiling)),
+     make_distributed_cooling(displacement, cool),
+     displacement);
+}
+
+} } } // end namespace boost::graph::distributed
+
+#endif // BOOST_GRAPH_DISTRIBUTED_FRUCHTERMAN_REINGOLD_HPP