graph_parallel/include/boost/graph/distributed/depth_first_search.hpp
2011-01-06 02:27:26 +00:00

308 lines
10 KiB
C++

// Copyright (C) 2004-2008 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_DFS_HPP
#define BOOST_GRAPH_DISTRIBUTED_DFS_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/graph_traits.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/graph/overloading.hpp>
#include <boost/graph/properties.hpp>
#include <boost/graph/distributed/concepts.hpp>
#include <boost/static_assert.hpp>
#include <boost/assert.hpp>
#include <boost/graph/parallel/process_group.hpp>
#include <boost/graph/parallel/container_traits.hpp>
namespace boost {
namespace graph { namespace distributed { namespace detail {
template<typename DistributedGraph, typename ColorMap, typename ParentMap,
typename ExploreMap, typename VertexIndexMap, typename DFSVisitor>
class parallel_dfs
{
typedef typename graph_traits<DistributedGraph>::vertex_iterator
vertex_iterator;
typedef typename graph_traits<DistributedGraph>::vertex_descriptor
vertex_descriptor;
typedef typename graph_traits<DistributedGraph>::out_edge_iterator
out_edge_iterator;
typedef typename boost::graph::parallel::process_group_type<DistributedGraph>
::type process_group_type;
typedef typename process_group_type::process_id_type process_id_type;
/**
* The first vertex in the pair is the local node (i) and the
* second vertex in the pair is the (possibly remote) node (j).
*/
typedef boost::parallel::detail::untracked_pair<vertex_descriptor, vertex_descriptor> vertex_pair;
typedef typename property_traits<ColorMap>::value_type color_type;
typedef color_traits<color_type> Color;
// Message types
enum { discover_msg = 10, return_msg = 50, visited_msg = 100 , done_msg = 150};
public:
parallel_dfs(const DistributedGraph& g, ColorMap color,
ParentMap parent, ExploreMap explore,
VertexIndexMap index_map, DFSVisitor vis)
: g(g), color(color), parent(parent), explore(explore),
index_map(index_map), vis(vis), pg(process_group(g)),
owner(get(vertex_owner, g)), next_out_edge(num_vertices(g))
{ }
void run(vertex_descriptor s)
{
vertex_iterator vi, vi_end;
for (boost::tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi) {
put(color, *vi, Color::white());
put(parent, *vi, *vi);
put(explore, *vi, *vi);
next_out_edge[get(index_map, *vi)] = out_edges(*vi, g).first;
vis.initialize_vertex(*vi, g);
}
vis.start_vertex(s, g);
if (get(owner, s) == process_id(pg)) {
send_oob(pg, get(owner, s), discover_msg, vertex_pair(s, s));
}
bool done = false;
while (!done) {
std::pair<process_id_type, int> msg = *pg.poll(true);
switch (msg.second) {
case discover_msg:
{
vertex_pair p;
receive_oob(pg, msg.first, msg.second, p);
if (p.first != p.second) {
// delete j from nomessage(j)
if (get(color, p.second) != Color::black())
local_put(color, p.second, Color::gray());
if (recover(p)) break;
}
if (get(color, p.first) == Color::white()) {
put(color, p.first, Color::gray());
put(parent, p.first, p.second);
vis.discover_vertex(p.first, g);
if (shift_center_of_activity(p.first)) break;
out_edge_iterator ei, ei_end;
for (boost::tie(ei,ei_end) = out_edges(p.first, g); ei != ei_end; ++ei)
{
// Notify everyone who may not know that the source
// vertex has been visited. They can then mark the
// corresponding color map entry gray.
if (get(parent, p.first) != target(*ei, g)
&& get(explore, p.first) != target(*ei, g)) {
vertex_pair visit(target(*ei, g), p.first);
send_oob(pg, get(owner, target(*ei, g)), visited_msg, visit);
}
}
}
}
break;
case visited_msg:
{
vertex_pair p;
receive_oob(pg, msg.first, msg.second, p);
// delete j from nomessage(j)
if (get(color, p.second) != Color::black())
local_put(color, p.second, Color::gray());
recover(p);
}
break;
case return_msg:
{
vertex_pair p;
receive_oob(pg, msg.first, msg.second, p);
// delete j from nomessage(i)
local_put(color, p.second, Color::black());
shift_center_of_activity(p.first);
}
break;
case done_msg:
{
receive_oob(pg, msg.first, msg.second, done);
// Propagate done message downward in tree
done = true;
process_id_type id = process_id(pg);
process_id_type left = 2*id + 1;
process_id_type right = left + 1;
if (left < num_processes(pg))
send_oob(pg, left, done_msg, done);
if (right < num_processes(pg))
send_oob(pg, right, done_msg, done);
}
break;
default:
BOOST_ASSERT(false);
}
}
}
private:
bool recover(const vertex_pair& p)
{
if (get(explore, p.first) == p.second) {
return shift_center_of_activity(p.first);
}
else
return false;
}
bool shift_center_of_activity(vertex_descriptor i)
{
for (out_edge_iterator ei = next_out_edge[get(index_map, i)],
ei_end = out_edges(i, g).second;
ei != ei_end; ++ei) {
vis.examine_edge(*ei, g);
vertex_descriptor k = target(*ei, g);
color_type target_color = get(color, k);
if (target_color == Color::black()) vis.forward_or_cross_edge(*ei, g);
else if (target_color == Color::gray()) vis.back_edge(*ei, g);
else {
put(explore, i, k);
vis.tree_edge(*ei, g);
vertex_pair p(k, i);
send_oob(pg, get(owner, k), discover_msg, p);
next_out_edge[get(index_map, i)] = ++ei;
return false;
}
}
next_out_edge[get(index_map, i)] = out_edges(i, g).second;
put(explore, i, i);
put(color, i, Color::black());
vis.finish_vertex(i, g);
if (get(parent, i) == i) {
send_oob(pg, 0, done_msg, true);
return true;
}
else {
vertex_pair ret(get(parent, i), i);
send_oob(pg, get(owner, ret.first), return_msg, ret);
}
return false;
}
const DistributedGraph& g;
ColorMap color;
ParentMap parent;
ExploreMap explore;
VertexIndexMap index_map;
DFSVisitor vis;
process_group_type pg;
typename property_map<DistributedGraph, vertex_owner_t>::const_type owner;
std::vector<out_edge_iterator> next_out_edge;
};
} // end namespace detail
template<typename DistributedGraph, typename ColorMap, typename ParentMap,
typename ExploreMap, typename VertexIndexMap, typename DFSVisitor>
void
tsin_depth_first_visit
(const DistributedGraph& g,
typename graph_traits<DistributedGraph>::vertex_descriptor s,
DFSVisitor vis, ColorMap color, ParentMap parent, ExploreMap explore,
VertexIndexMap index_map)
{
typedef typename graph_traits<DistributedGraph>::directed_category
directed_category;
BOOST_STATIC_ASSERT(
(is_convertible<directed_category, undirected_tag>::value));
set_property_map_role(vertex_color, color);
graph::distributed::detail::parallel_dfs
<DistributedGraph, ColorMap, ParentMap, ExploreMap, VertexIndexMap,
DFSVisitor> do_dfs(g, color, parent, explore, index_map, vis);
do_dfs.run(s);
using boost::graph::parallel::process_group;
synchronize(process_group(g));
}
template<typename DistributedGraph, typename DFSVisitor,
typename VertexIndexMap>
void
tsin_depth_first_visit
(const DistributedGraph& g,
typename graph_traits<DistributedGraph>::vertex_descriptor s,
DFSVisitor vis,
VertexIndexMap index_map)
{
typedef typename graph_traits<DistributedGraph>::vertex_descriptor
vertex_descriptor;
std::vector<default_color_type> colors(num_vertices(g));
std::vector<vertex_descriptor> parent(num_vertices(g));
std::vector<vertex_descriptor> explore(num_vertices(g));
tsin_depth_first_visit
(g, s,
vis,
make_iterator_property_map(colors.begin(), index_map),
make_iterator_property_map(parent.begin(), index_map),
make_iterator_property_map(explore.begin(), index_map),
index_map);
}
template<typename DistributedGraph, typename DFSVisitor,
typename VertexIndexMap>
void
tsin_depth_first_visit
(const DistributedGraph& g,
typename graph_traits<DistributedGraph>::vertex_descriptor s,
DFSVisitor vis)
{
tsin_depth_first_visit(g, s, vis, get(vertex_index, g));
}
} // end namespace distributed
using distributed::tsin_depth_first_visit;
} // end namespace graph
template<typename DistributedGraph, typename DFSVisitor>
void
depth_first_visit
(const DistributedGraph& g,
typename graph_traits<DistributedGraph>::vertex_descriptor s,
DFSVisitor vis)
{
graph::tsin_depth_first_visit(g, s, vis, get(vertex_index, g));
}
} // end namespace boost
#endif // BOOST_GRAPH_DISTRIBUTED_DFS_HPP