// Copyright (C) 2004-2006 The Trustees of Indiana University. | |
// Copyright (C) 2002 Brad King and Douglas Gregor | |
// 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 | |
// Brian Barrett | |
#ifndef BOOST_PARALLEL_GRAPH_PAGE_RANK_HPP | |
#define BOOST_PARALLEL_GRAPH_PAGE_RANK_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/assert.hpp> | |
#include <boost/graph/overloading.hpp> | |
#include <boost/graph/page_rank.hpp> | |
#include <boost/graph/distributed/concepts.hpp> | |
#include <boost/property_map/parallel/distributed_property_map.hpp> | |
#include <boost/property_map/parallel/caching_property_map.hpp> | |
#include <boost/graph/parallel/algorithm.hpp> | |
#include <boost/graph/parallel/container_traits.hpp> | |
// #define WANT_MPI_ONESIDED 1 | |
namespace boost { namespace graph { namespace distributed { | |
namespace detail { | |
#ifdef WANT_MPI_ONESIDED | |
template<typename Graph, typename RankMap, typename owner_map_t> | |
void page_rank_step(const Graph& g, RankMap from_rank, MPI_Win to_win, | |
typename property_traits<RankMap>::value_type damping, | |
owner_map_t owner) | |
{ | |
typedef typename property_traits<RankMap>::value_type rank_type; | |
int me, ret; | |
MPI_Comm_rank(MPI_COMM_WORLD, &me); | |
// MPI_Accumulate is not required to store the value of the data | |
// being sent, only the address. The value of the memory location | |
// must not change until the end of the access epoch, meaning the | |
// call to MPI_Fence. We therefore store the updated value back | |
// into the from_rank map before the accumulate rather than using | |
// a temporary. We're going to reset the values in the from_rank | |
// before the end of page_rank_step() anyway, so this isn't a huge | |
// deal. But MPI-2 One-sided is an abomination. | |
BGL_FORALL_VERTICES_T(u, g, Graph) { | |
put(from_rank, u, (damping * get(from_rank, u) / out_degree(u, g))); | |
BGL_FORALL_ADJ_T(u, v, g, Graph) { | |
ret = MPI_Accumulate(&(from_rank[u]), | |
1, MPI_DOUBLE, | |
get(owner, v), local(v), | |
1, MPI_DOUBLE, MPI_SUM, to_win); | |
BOOST_ASSERT(MPI_SUCCESS == ret); | |
} | |
} | |
MPI_Win_fence(0, to_win); | |
// Set new rank maps for the other map. Do this now to get around | |
// the stupid synchronization rules of MPI-2 One-sided | |
BGL_FORALL_VERTICES_T(v, g, Graph) put(from_rank, v, rank_type(1 - damping)); | |
} | |
#endif | |
template<typename T> | |
struct rank_accumulate_reducer { | |
BOOST_STATIC_CONSTANT(bool, non_default_resolver = true); | |
template<typename K> | |
T operator()(const K&) const { return T(0); } | |
template<typename K> | |
T operator()(const K&, const T& x, const T& y) const { return x + y; } | |
}; | |
} // end namespace detail | |
template<typename Graph, typename RankMap, typename Done, typename RankMap2> | |
void | |
page_rank_impl(const Graph& g, RankMap rank_map, Done done, | |
typename property_traits<RankMap>::value_type damping, | |
typename graph_traits<Graph>::vertices_size_type n, | |
RankMap2 rank_map2) | |
{ | |
typedef typename property_traits<RankMap>::value_type rank_type; | |
int me; | |
MPI_Comm_rank(MPI_COMM_WORLD, &me); | |
typedef typename property_map<Graph, vertex_owner_t> | |
::const_type vertex_owner_map; | |
typename property_map<Graph, vertex_owner_t>::const_type | |
owner = get(vertex_owner, g); | |
typedef typename boost::graph::parallel::process_group_type<Graph> | |
::type process_group_type; | |
typedef typename process_group_type::process_id_type process_id_type; | |
process_group_type pg = process_group(g); | |
process_id_type id = process_id(pg); | |
BOOST_ASSERT(me == id); | |
rank_type initial_rank = rank_type(rank_type(1) / n); | |
BGL_FORALL_VERTICES_T(v, g, Graph) put(rank_map, v, initial_rank); | |
#ifdef WANT_MPI_ONESIDED | |
BOOST_ASSERT(sizeof(rank_type) == sizeof(double)); | |
bool to_map_2 = true; | |
MPI_Win win, win2; | |
MPI_Win_create(&(rank_map[*(vertices(g).first)]), | |
sizeof(double) * num_vertices(g), | |
sizeof(double), | |
MPI_INFO_NULL, MPI_COMM_WORLD, &win); | |
MPI_Win_set_name(win, "rank_map_win"); | |
MPI_Win_create(&(rank_map2[*(vertices(g).first)]), | |
sizeof(double) * num_vertices(g), | |
sizeof(double), | |
MPI_INFO_NULL, MPI_COMM_WORLD, &win2); | |
MPI_Win_set_name(win, "rank_map2_win"); | |
// set initial rank maps for the first iteration... | |
BGL_FORALL_VERTICES_T(v, g, Graph) put(rank_map2, v, rank_type(1 - damping)); | |
MPI_Win_fence(0, win); | |
MPI_Win_fence(0, win2); | |
while ((to_map_2 && !done(rank_map, g)) || | |
(!to_map_2 && !done(rank_map2, g))) { | |
if (to_map_2) { | |
graph::distributed::detail::page_rank_step(g, rank_map, win2, damping, owner); | |
to_map_2 = false; | |
} else { | |
graph::distributed::detail::page_rank_step(g, rank_map2, win, damping, owner); | |
to_map_2 = true; | |
} | |
} | |
synchronize(boost::graph::parallel::process_group(g)); | |
MPI_Win_free(&win); | |
MPI_Win_free(&win2); | |
#else | |
// The ranks accumulate after each step. | |
rank_map.set_reduce(detail::rank_accumulate_reducer<rank_type>()); | |
rank_map2.set_reduce(detail::rank_accumulate_reducer<rank_type>()); | |
rank_map.set_consistency_model(boost::parallel::cm_flush | boost::parallel::cm_reset); | |
rank_map2.set_consistency_model(boost::parallel::cm_flush | boost::parallel::cm_reset); | |
bool to_map_2 = true; | |
while ((to_map_2 && !done(rank_map, g)) || | |
(!to_map_2 && !done(rank_map2, g))) { | |
/** | |
* PageRank can implemented slightly more efficiently on a | |
* bidirectional graph than on an incidence graph. However, | |
* distributed PageRank requires that we have the rank of the | |
* source vertex available locally, so we force the incidence | |
* graph implementation, which pushes rank from source to | |
* target. | |
*/ | |
typedef incidence_graph_tag category; | |
if (to_map_2) { | |
graph::detail::page_rank_step(g, rank_map, rank_map2, damping, | |
category()); | |
to_map_2 = false; | |
} else { | |
graph::detail::page_rank_step(g, rank_map2, rank_map, damping, | |
category()); | |
to_map_2 = true; | |
} | |
using boost::graph::parallel::process_group; | |
synchronize(process_group(g)); | |
} | |
rank_map.reset(); | |
#endif | |
if (!to_map_2) | |
BGL_FORALL_VERTICES_T(v, g, Graph) put(rank_map, v, get(rank_map2, v)); | |
} | |
template<typename Graph, typename RankMap, typename Done, typename RankMap2> | |
void | |
page_rank(const Graph& g, RankMap rank_map, Done done, | |
typename property_traits<RankMap>::value_type damping, | |
typename graph_traits<Graph>::vertices_size_type n, | |
RankMap2 rank_map2 | |
BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, distributed_graph_tag)) | |
{ | |
(page_rank_impl)(g, rank_map, done, damping, n, rank_map2); | |
} | |
template<typename MutableGraph> | |
void | |
remove_dangling_links(MutableGraph& g | |
BOOST_GRAPH_ENABLE_IF_MODELS_PARM(MutableGraph, | |
distributed_graph_tag)) | |
{ | |
typename graph_traits<MutableGraph>::vertices_size_type old_n; | |
do { | |
old_n = num_vertices(g); | |
typename graph_traits<MutableGraph>::vertex_iterator vi, vi_end; | |
for (boost::tie(vi, vi_end) = vertices(g); vi != vi_end; /* in loop */) { | |
typename graph_traits<MutableGraph>::vertex_descriptor v = *vi++; | |
if (out_degree(v, g) == 0) { | |
clear_vertex(v, g); | |
remove_vertex(v, g); | |
} | |
} | |
} while (num_vertices(g) < old_n); | |
} | |
} // end namespace distributed | |
using distributed::page_rank; | |
using distributed::remove_dangling_links; | |
} } // end namespace boost::graph | |
#endif // BOOST_PARALLEL_GRAPH_PAGE_RANK_HPP |