#include <hdf5.h>
#include <mpi.h>
#include <stdio.h>

/*
 * This program measures the time for copying a dataset of 32M size
 * between two parallel HDF5 files. The dataset has a contiguous layout,
 * which means the dataset object consists of metadata and raw data.
 *
 * mpicc -Wall -O2 -o h5copy_mpio h5copy_mpio.c -lhdf5
 */
int main(int argc, char **argv)
{
  double start, stop;
  int step, rank, i;
  hid_t file1, file2, fapl, space, dset;

  MPI_Init(&argc, &argv);
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);

  fapl = H5Pcreate(H5P_FILE_ACCESS);
  H5Pset_fapl_mpio(fapl, MPI_COMM_WORLD, MPI_INFO_NULL);

  file1 = H5Fcreate("h5copy_mpio_1.h5", H5F_ACC_TRUNC, H5P_DEFAULT, fapl);

  hsize_t dims[1] = {4194304};
  space = H5Screate_simple(1, dims, NULL);
  dset = H5Dcreate(file1, "position", H5T_NATIVE_DOUBLE, space, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
  H5Sclose(space);
  H5Dclose(dset);

  H5Fflush(file1, H5F_SCOPE_LOCAL);
  H5Fclose(file1);

  file1 = H5Fopen("h5copy_mpio_1.h5", H5F_ACC_RDONLY, fapl);
  file2 = H5Fcreate("h5copy_mpio_2.h5", H5F_ACC_TRUNC, H5P_DEFAULT, fapl);

  start = MPI_Wtime();
  H5Ocopy(file1, "position", file2, "position", H5P_DEFAULT, H5P_DEFAULT);
  H5Fflush(file2, H5F_SCOPE_LOCAL);
  stop = MPI_Wtime();
  if (rank == 0) printf("%.3g s\n", stop-start);

  H5Fclose(file1);
  H5Fclose(file2);
  H5Pclose(fapl);

  MPI_Finalize();
}