c:hdf5 compression test code

hdf5_compression.c

#include <stdio.h>
#include <hdf5.h>
#include <stdlib.h>
#include <hdf5_hl.h>
#include <math.h>

int main() {
    uint dim = 512;
    uint n_cell = (uint)pow(512, 3);
    double fill_frac = 0.6;
    uint fill_n = (uint)(fill_frac * n_cell);

    float* data = calloc(n_cell, sizeof(float));

    for (int ii = 0; ii < fill_n; ++ii) {
        data[arc4random_uniform(n_cell)] = (float)(arc4random_uniform(100)*0.1);
    }

    hid_t f_id = H5Fcreate("test.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
    hsize_t hdim[3] = {dim, dim, dim};

    // compressed write ------------------------
    hid_t dspace_id = H5Screate_simple(3, hdim, NULL);
    hid_t plist_id  = H5Pcreate(H5P_DATASET_CREATE);

    hsize_t chunks[3] = {512, 512, 1};
    H5Pset_chunk(plist_id, 3, chunks);
    H5Pset_deflate(plist_id, 6);

    hid_t dset_id = H5Dcreate(f_id, "compressed", H5T_NATIVE_FLOAT,
                             dspace_id, H5P_DEFAULT, plist_id, H5P_DEFAULT);

    H5Dwrite(dset_id, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, H5P_DEFAULT, data);

    H5Sclose(dspace_id);
    H5Dclose(dset_id);
    H5Pclose(plist_id);
    // -----------------------------------------

    // standard write --------------------------
    H5LTmake_dataset_float(f_id, "standard", 3, hdim, data);
    // -----------------------------------------

    H5Fclose(f_id);

    free(data);
    return 0;
}