#include "BufferExchange.h"

int main( int argc, char **argv )
{
	int rank, nranks;
	IntVec peers;
	BufferExchange<int> *be;

	int n_iterations = 10;
	int buffer_size = 100;
	char logfile_path[512];
	
	MPI_Init( &argc, &argv );
	
	MPI_Comm_size( MPI_COMM_WORLD, &nranks );
	MPI_Comm_rank( MPI_COMM_WORLD, &rank );
	
	//
	// Set up separate log file for each process
	//
	sprintf( logfile_path, "log.%d", rank );
	if( (logfile=fopen(logfile_path,"w")) == NULL )
	{
		ERROR_MACRO( "Unable to open logfile '%s'\n", logfile_path );
	}
	
	//
	// Talk to all other ranks (but not self)
	//
	for( int i=0; i<nranks; i++ )
	{
		if( i != rank ) peers.push_back( i );
	}
	
	//
	// We'll send and receive integer buffers for simplicity
	//
	be = new BufferExchange<int>;
	
	//
	// Loop over sends/receive integer buffers to/from peers.
	//
	// Note that actual buffer sizes increase by 1 per loop iteration, so we expect to
	// see occasional increases in memory use when buffers are received from other ranks.
	// The details of exactly when this happens depend on the std::vector reallocation
	// strategy via the std::vector.resize() calls in BufferExchange::FullExchange() etc.
	//
	// We also reset/clear some other buffers, but as we're talking to a fixed number of
	// peers we're likely to just end up re0using the previously allocated/free'd
	// memory for those particular vectors.
	//
	for( int loop=0; loop<n_iterations; loop++ )
	{
		Log( "\n" );
		Log( "Loop iteration %d...\n", loop );
		
		// setup send buffers
		be->Clear( peers );
		for( size_t pi=0; pi<peers.size(); pi++ )
		{
//			buffer_size = loop; // uncomment this for variable buffer sizes
			be->send_buffers[pi].clear();
			for( int i=0; i<buffer_size; i++ ) be->send_buffers[pi].push_back( 0 ); // arbitrary integers in the buffers
		}

		// exchange buffers with peers
		be->FullExchange();
	}
	
	MPI_Barrier( MPI_COMM_WORLD );
	
	delete be;
	fclose( logfile );

	MPI_Finalize();
	
	return 0;
}