Chris@16: // Copyright 2005 The Trustees of Indiana University.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software
Chris@16: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  Authors: Douglas Gregor
Chris@16: //           Andrew Lumsdaine
Chris@16: #ifndef BOOST_PARALLEL_GLOBAL_INDEX_MAP_HPP
Chris@16: #define BOOST_PARALLEL_GLOBAL_INDEX_MAP_HPP
Chris@16: 
Chris@16: #include <boost/property_map/property_map.hpp>
Chris@16: #include <vector>
Chris@16: #include <boost/shared_ptr.hpp>
Chris@16: 
Chris@16: namespace boost { namespace parallel {
Chris@16: 
Chris@16: template<typename IndexMap, typename GlobalMap>
Chris@16: class global_index_map
Chris@16: {
Chris@16: public:
Chris@16:   typedef typename property_traits<IndexMap>::key_type key_type;
Chris@16:   typedef typename property_traits<IndexMap>::value_type value_type;
Chris@16:   typedef value_type reference;
Chris@16:   typedef readable_property_map_tag category;
Chris@16: 
Chris@16:   template<typename ProcessGroup>
Chris@16:   global_index_map(ProcessGroup pg, value_type num_local_indices, 
Chris@16:                    IndexMap index_map, GlobalMap global)
Chris@16:     : index_map(index_map), global(global)
Chris@16:   {
Chris@16:     typedef typename ProcessGroup::process_id_type process_id_type;
Chris@16:     starting_index.reset(new std::vector<value_type>(num_processes(pg) + 1));
Chris@16:     send(pg, 0, 0, num_local_indices);
Chris@16:     synchronize(pg);
Chris@16:     
Chris@16:     // Populate starting_index in all processes
Chris@16:     if (process_id(pg) == 0) {
Chris@16:       (*starting_index)[0] = 0;
Chris@16:       for (process_id_type src = 0; src < num_processes(pg); ++src) {
Chris@16:         value_type n;
Chris@16:         receive(pg, src, 0, n);
Chris@16:         (*starting_index)[src + 1] = (*starting_index)[src] + n;
Chris@16:       }
Chris@16:       for (process_id_type dest = 1; dest < num_processes(pg); ++dest)
Chris@16:         send(pg, dest, 1, &starting_index->front(), num_processes(pg));
Chris@16:       synchronize(pg);
Chris@16:     } else {
Chris@16:       synchronize(pg);
Chris@16:       receive(pg, 0, 1, &starting_index->front(), num_processes(pg));
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   friend inline value_type 
Chris@16:   get(const global_index_map& gim, const key_type& x)
Chris@16:   {
Chris@16:     using boost::get;
Chris@16:     return (*gim.starting_index)[get(gim.global, x).first]
Chris@16:            + get(gim.index_map, x);
Chris@16:   }
Chris@16: 
Chris@16: private:
Chris@16:   shared_ptr<std::vector<value_type> > starting_index;
Chris@16:   IndexMap index_map;
Chris@16:   GlobalMap global;
Chris@16: };
Chris@16: 
Chris@16: } } // end namespace boost::parallel
Chris@16: 
Chris@16: #endif // BOOST_PARALLEL_GLOBAL_INDEX_MAP_HPP