HDF5 minimal example

hdf5.cpp

@@ -13,11 +13,15 @@
 #include <iostream>
 #include <vector>
 
+
 const hsize_t CHUNK_SIZE = 314;
 
 int main(int argc, char** argv)
 {
   MPI_Init(&argc, &argv);
+  for (int i = 0; i < argc; ++i)
+        std::cout << argv[i] << "\n";
+  int data_length=std::atoi(argv[1]);
   int comm_size, comm_rank;
   assert(MPI_SUCCESS == MPI_Comm_size(MPI_COMM_WORLD, &comm_size));
   assert(MPI_SUCCESS == MPI_Comm_rank(MPI_COMM_WORLD, &comm_rank));
@@ -30,21 +34,21 @@ int main(int argc, char** argv)
 
   // Let's create some sample data!
   // MPI ranks have (100 + rank) integers worth of data
-  std::vector<int> v(100 + comm_rank, comm_rank);
+  std::vector<int> v(data_length, comm_rank+1);
 
   // The extent of the dataspace in the file can be computed accordingly.
-  hsize_t size = 100*comm_size+ comm_size*(comm_size-1)/2 ;
+  hsize_t size = data_length*comm_size; //+ comm_size*(comm_size-1)/2;
  
   printf("Size %d", size);
 
   // Make a dataset!
   // I can't believe that takes 10 lines of code :-(
-  hsize_t infty = 406;
+  hsize_t infty = H5S_UNLIMITED;;
   hid_t fspace = H5Screate_simple(1, &size, &infty);
   assert(fspace >= 0);
   hid_t dcpl = H5Pcreate(H5P_DATASET_CREATE);
   assert(dcpl >= 0);
-  //assert(H5Pset_chunk(dcpl, 1, &CHUNK_SIZE) >= 0);
+  assert(H5Pset_chunk(dcpl, 1, &CHUNK_SIZE) >= 0);
   hid_t dset = H5Dcreate(file, "1D", H5T_STD_I32LE, fspace, H5P_DEFAULT, dcpl,
                          H5P_DEFAULT);
   assert(dset >= 0);
@@ -55,17 +59,13 @@ int main(int argc, char** argv)
   hid_t mspace = H5Screate_simple(1, &blk, NULL);
 
   assert(H5Sselect_all(mspace) >= 0);
-  offset =
-      comm_rank / 2 * 100 + (comm_rank - 1) / 2 * ((comm_rank - 1) / 2 + 1);
-
-  offset = comm_rank*100; //+(comm_rank)*(comm_rank-1)/2;
+  offset = (comm_rank)*data_length; //+comm_rank;
 
   printf("offset %d of rank %d \n", offset, comm_rank);
   assert(H5Sselect_hyperslab(fspace, H5S_SELECT_SET, &offset, NULL, &one,
                              &blk) >= 0);
 
   assert(H5Sselect_all(mspace) >= 0);
-  offset = comm_rank * 100;
   assert(H5Sselect_hyperslab(fspace, H5S_SELECT_SET, &offset, NULL, &one,
                                 &blk) >= 0);