MPIDefaultAllToAllCommunicator.cpp

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#include "MPIDefaultAllToAllCommunicator.h"

#include <numeric>
#include <functional>
#include <algorithm>

using std::logical_or;
using std::accumulate;
using std::fill;

using std::cerr;

MPIDefaultAllToAllCommunicator::MPIDefaultAllToAllCommunicator(
    MPIInputBufferVector & mpiInputBuffers,
    MPIOutputBufferVector & mpiOutputBuffers,
    MPI::Intracomm & comm,
    vector<bool> &incomingConnections,
    vector<bool> &outgoingConnections) :
        MPIAllToAllCommunicator(mpiInputBuffers, mpiOutputBuffers, comm, incomingConnections, outgoingConnections)
{
    needsToSend.resize(comm.Get_size(), true);    
    needsToReceive.resize(comm.Get_size(), true);
}

void MPIDefaultAllToAllCommunicator::prepare()
{
    fill(needsToSend.begin(), needsToSend.end(), true);
    fill(needsToReceive.begin(), needsToReceive.end(), true);
    fill(hasNextToSend.begin(), hasNextToSend.end(), true);
    hasNextToSend[mpi_comm.Get_rank()] = false;
    needsToSend[mpi_comm.Get_rank()] = false;
    needsToReceive[mpi_comm.Get_rank()] = false;
}


void MPIDefaultAllToAllCommunicator::doExchangeAlgorithm()
{
    // first setup the finished flag in the output buffers
    outputBuffers.setFinishedFlag(!accumulate(hasNextToSend.begin(), hasNextToSend.end(), false, logical_or<bool>()));
    
    MPIExchangeBlocksInfo & input_blocks = inputBuffers.getMPIExchangeBlocksInfo();
    
    MPIExchangeBlocksInfo &output_blocks = outputBuffers.getMPIExchangeBlocksInfo();
    
    // then do the exchange
    mpi_comm.Alltoallw((void *)outputBuffers.getBaseBufferPtr(),
                       output_blocks.counts, output_blocks.displs, output_blocks.datatypes,
                       (void *)inputBuffers.getBaseBufferPtr(),
                       input_blocks.counts, input_blocks.displs, input_blocks.datatypes);
}

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