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			2.4 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
		
		
			
		
	
	
			79 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
|   | // Copyright 2005 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_PARALLEL_INPLACE_ALL_TO_ALL_HPP | ||
|  | #define BOOST_GRAPH_PARALLEL_INPLACE_ALL_TO_ALL_HPP | ||
|  | 
 | ||
|  | #ifndef BOOST_GRAPH_USE_MPI | ||
|  | #error "Parallel BGL files should not be included unless <boost/graph/use_mpi.hpp> has been included" | ||
|  | #endif | ||
|  | 
 | ||
|  | // | ||
|  | // Implements the inplace all-to-all communication algorithm. | ||
|  | // | ||
|  | #include <vector> | ||
|  | #include <iterator> | ||
|  | 
 | ||
|  | namespace boost { namespace parallel {  | ||
|  | 
 | ||
|  | template<typename ProcessGroup, typename T> | ||
|  | // where {LinearProcessGroup<ProcessGroup>, MessagingProcessGroup<ProcessGroup>} | ||
|  | void  | ||
|  | inplace_all_to_all(ProcessGroup pg,  | ||
|  |                    const std::vector<std::vector<T> >& outgoing, | ||
|  |                    std::vector<std::vector<T> >& incoming) | ||
|  | { | ||
|  |   typedef typename std::vector<T>::size_type size_type; | ||
|  | 
 | ||
|  |   typedef typename ProcessGroup::process_size_type process_size_type; | ||
|  |   typedef typename ProcessGroup::process_id_type process_id_type; | ||
|  | 
 | ||
|  |   process_size_type p = num_processes(pg); | ||
|  | 
 | ||
|  |   // Make sure there are no straggling messages | ||
|  |   synchronize(pg); | ||
|  | 
 | ||
|  |   // Send along the count (always) and the data (if count > 0) | ||
|  |   for (process_id_type dest = 0; dest < p; ++dest) { | ||
|  |     if (dest != process_id(pg)) { | ||
|  |       send(pg, dest, 0, outgoing[dest].size()); | ||
|  |       if (!outgoing[dest].empty()) | ||
|  |         send(pg, dest, 1, &outgoing[dest].front(), outgoing[dest].size()); | ||
|  |     } | ||
|  |   } | ||
|  | 
 | ||
|  |   // Make sure all of the data gets transferred | ||
|  |   synchronize(pg); | ||
|  | 
 | ||
|  |   // Receive the sizes and data | ||
|  |   for (process_id_type source = 0; source < p; ++source) { | ||
|  |     if (source != process_id(pg)) { | ||
|  |       size_type size; | ||
|  |       receive(pg, source, 0, size); | ||
|  |       incoming[source].resize(size); | ||
|  |       if (size > 0) | ||
|  |         receive(pg, source, 1, &incoming[source].front(), size); | ||
|  |     } else if (&incoming != &outgoing) { | ||
|  |       incoming[source] = outgoing[source]; | ||
|  |     } | ||
|  |   } | ||
|  | } | ||
|  | 
 | ||
|  | template<typename ProcessGroup, typename T> | ||
|  | // where {LinearProcessGroup<ProcessGroup>, MessagingProcessGroup<ProcessGroup>} | ||
|  | void  | ||
|  | inplace_all_to_all(ProcessGroup pg, std::vector<std::vector<T> >& data) | ||
|  | { | ||
|  |   inplace_all_to_all(pg, data, data); | ||
|  | } | ||
|  | 
 | ||
|  | } } // end namespace boost::parallel | ||
|  | 
 | ||
|  | #endif // BOOST_GRAPH_PARALLEL_INPLACE_ALL_TO_ALL_HPP |