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---------------------- ./MANIFEST ./html/study.html [NEW] ./html/study_1000x1000.gif [NEW] ./html/study_250x250.gif [NEW] ./html/study_499x499.gif [NEW] ./html/study_5000x1000.gif [NEW] ./html/study_500x500.gif [NEW] ./html/study_p1.gif [NEW] ./html/study_p1.obj [NEW] The conclusions from a study of the HDF5 chunking layout. Shows overhead and disk seeking.
132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
/*
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* Copyright (C) 1998 Spizella Software
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* All rights reserved.
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*
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* Programmer: Robb Matzke <matzke@llnl.gov>
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* Friday, January 30, 1998
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*
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* Purpose: Tests extendable datasets.
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*/
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#include <assert.h>
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#include <hdf5.h>
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#define NX 100 /* USE AN EVEN NUMBER!*/
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#define NY 100 /* USE AN EVEN NUMBER!*/
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/*-------------------------------------------------------------------------
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* Function: main
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*
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* Purpose: Tests extendable datasets
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*
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* Return: Success: exit(0)
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*
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* Failure: exit(non-zero)
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*
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* Programmer: Robb Matzke
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* Friday, January 30, 1998
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*
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* Modifications:
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*
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*-------------------------------------------------------------------------
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*/
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int
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main (void)
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{
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hid_t file, dataset, mem_space, file_space, cparms;
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herr_t status;
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int i, j, k, m;
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static int buf1[NY][NX], buf2[NX/2][NY/2];
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static const size_t dims[2] = {NX, NY};
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static const size_t half_dims[2] = {NX/2, NY/2};
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static const size_t chunk_dims[2] = {NX/2, NY/2};
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static size_t maxdims[2] = {H5P_UNLIMITED, H5P_UNLIMITED};
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static size_t size[2];
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int offset[2];
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/* Initialize buffer and space */
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for (i=0; i<NX; i++) {
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for (j=0; j<NY; j++) {
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buf1[i][j] = i*NY+j;
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}
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}
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mem_space = H5Pcreate_simple (2, dims, maxdims);
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assert (mem_space>=0);
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/* Create the file */
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file = H5Fcreate ("extend.h5", H5ACC_OVERWRITE, H5C_DEFAULT, H5C_DEFAULT);
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assert (file>=0);
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/* Create the dataset which is originally NX by NY */
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cparms = H5Ccreate (H5C_DATASET_CREATE);
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assert (cparms>=0);
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status = H5Cset_chunk (cparms, 2, chunk_dims);
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assert (status>=0);
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dataset = H5Dcreate (file, "dataset", H5T_NATIVE_INT, mem_space, cparms);
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assert (dataset>=0);
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/* Write the data */
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for (i=0; i<5; i++) {
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for (j=0; j<5; j++) {
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/* Extend the dataset */
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offset[0] = i * NX;
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offset[1] = j * NY;
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size[0] = offset[0] + NX;
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size[1] = offset[1] + NY;
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status = H5Dextend (dataset, size);
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assert (status>=0);
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/* Select a hyperslab */
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file_space = H5Dget_space (dataset);
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assert (file_space>=0);
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status = H5Pset_hyperslab (file_space, offset, dims, NULL);
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assert (status>=0);
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/* Write to the hyperslab */
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status = H5Dwrite (dataset, H5T_NATIVE_INT, mem_space, file_space,
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H5C_DEFAULT, buf1);
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assert (status>=0);
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H5Pclose (file_space);
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}
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}
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H5Pclose (mem_space);
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/* Read the data */
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mem_space = H5Pcreate_simple (2, half_dims, NULL);
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file_space = H5Dget_space (dataset);
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for (i=0; i<10; i++) {
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for (j=0; j<10; j++) {
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/* Select a hyperslab */
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offset[0] = i * NX/2;
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offset[1] = j * NY/2;
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assert (file_space>=0);
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status = H5Pset_hyperslab (file_space, offset, half_dims, NULL);
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assert (status>=0);
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/* Read */
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status = H5Dread (dataset, H5T_NATIVE_INT, mem_space, file_space,
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H5C_DEFAULT, buf2);
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assert (status>=0);
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/* Compare */
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for (k=0; k<NX/2; k++) {
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for (m=0; m<NY/2; m++) {
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assert (buf2[k][m]==buf1[(i%2)*NX/2+k][(j%2)*NY/2+m]);
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}
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}
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}
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}
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H5Dclose (dataset);
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H5Fclose (file);
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exit (0);
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}
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