void dummy_operations::run_collective_dummy_operations() {
int rank, size;
MPI_Comm_rank( MPI_COMM_WORLD, &rank);
MPI_Comm_size( MPI_COMM_WORLD, &size);
// Run Broadcast
{
int x;
MPI_Comm_rank( MPI_COMM_WORLD, &x);
MPI_Bcast(&x, 1, MPI_INT, 0, MPI_COMM_WORLD);
}
// Run Allgather.
{
int x, size;
MPI_Comm_rank( MPI_COMM_WORLD, &x);
MPI_Comm_size( MPI_COMM_WORLD, &size);
std::vector<int> rcv(size);
MPI_Allgather(&x, 1, MPI_INT, &rcv[0], 1, MPI_INT, MPI_COMM_WORLD);
}
// Run Allreduce.
{
int x;
MPI_Comm_rank( MPI_COMM_WORLD, &x);
int y = 0;
MPI_Allreduce(&x, &y, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
}
// Dummy Prefix Sum
{
int x = 1;
int y = 0;
MPI_Scan(&x, &y, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
}
// Run Alltoallv.
{
std::vector<int> snd(size);
std::vector<int> rcv(size);
std::vector<int> scounts(size, 1);
std::vector<int> rcounts(size, 1);
std::vector<int> sdispls(size);
std::vector<int> rdispls(size);
for (int i = 0, iend = sdispls.size(); i < iend; ++i) {
sdispls[i] = rdispls[i] = i;
}
MPI_Alltoallv(&snd[0], &scounts[0], &sdispls[0], MPI_INT,
&rcv[0], &rcounts[0], &rdispls[0], MPI_INT, MPI_COMM_WORLD);
}
}
vector<vector<int> > MPIDistribution::MPILayerGatherVariables(vector<vector<int> > data)
{
MPI_Comm* comm = MPIGetCommLayer(); // communicator for nodes in layer
vector<vector<int> > gatheredData(data.size());
for(int i=0;i<data.size();i++)
{
data[i].push_back(0); // will be removed later, allgatherv may not like zero-sized vectors
int sizeLocal = data[i].size();
int totalSize;
MPI_Allreduce(&sizeLocal,&totalSize, 1,MPI_INT,MPI_SUM,*comm);
vector<int> totalIndexes(totalSize);
vector<int> rcounts(m_mpiSizeLocal);
vector<int> displs(m_mpiSizeLocal);
// counts from each node
MPI_Allgather( &sizeLocal, 1, MPI_INT, &rcounts[0], 1, MPI_INT, *comm);
for(int j=1;j<rcounts.size();j++)
{
displs[j] = rcounts[j-1]+displs[j-1];
}
MPI_Allgatherv( &data[i][0],data[i].size(),MPI_INT,&totalIndexes[0],&rcounts[0],&displs[0],MPI_INT,*comm);
// remove all artificial values
for(int j=rcounts.size()-1;j>-1;j--)
{
totalIndexes.erase(totalIndexes.begin() + displs[j] + rcounts[j] - 1);
}
gatheredData[i] = totalIndexes;
}
return gatheredData;
}
