#include <mpi.h>
#include <hpc/mpi/matrix.h>
#include <hpc/matvec/gematrix.h>
#include <hpc/matvec/print.h>
#include <hpc/matvec/apply.h>

int main(int argc, char** argv) {
   MPI_Init(&argc, &argv);

   int nof_processes; MPI_Comm_size(MPI_COMM_WORLD, &nof_processes);
   int rank; MPI_Comm_rank(MPI_COMM_WORLD, &rank);

   using namespace hpc::matvec;
   using namespace hpc::mpi;
   using namespace hpc::aux;

   using Matrix = GeMatrix<double>;
   using Index = typename Matrix::Index;
   int share = 3;
   int num_rows = nof_processes * share + 1;
   int num_cols = 5;

   Matrix A(num_rows, num_cols); /* entire matrix */
   MPI_Datatype rowtype_A = get_row_type(A);

   Slices<int> slices(nof_processes, num_rows);
   Matrix B(slices.size(rank), num_cols,
      StorageOrder::RowMajor); /* individual share */
   MPI_Datatype rowtype_B = get_row_type(B);

   if (rank == 0) {
      apply(A, [](double& val, Index i, Index j) -> void {
	 val = i * 100 + j;
      });
   }

   scatter_by_row(A, B, 0, MPI_COMM_WORLD);
   apply(B, [=](double& val, Index i, Index j) -> void {
      val += 10000 * (rank + 1);
   });
   gather_by_row(B, A, 0, MPI_COMM_WORLD);

   MPI_Finalize();

   if (rank == 0) {
      print(A, "A");
   }
}