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authorAllen Byrne <50328838+byrnHDF@users.noreply.github.com>2023-11-27 21:30:15 (GMT)
committerGitHub <noreply@github.com>2023-11-27 21:30:15 (GMT)
commitfc88fcde1091cf12c1e88c783a14ee0f1cffe31c (patch)
tree91b88b62cd30ed37ee9227e43989e95035be43c3 /HDF5Examples/C/Perf/h5slabwrite.c
parenta067bf71f57723d2dfca7dfe2ffd9ea502eccd4f (diff)
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Develop merge examples (#3851)
* Merge examples repo into library * Change grepTest to be more fault-tolerant * Update examples macro file * Exclude all Fortran examples from doxygen
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+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group. *
+ * All rights reserved. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/* This example shows different data writing patterns to generate data files
+ * that will exhibit substantially different data read speed. The files
+ * contain 2-D chunk storage datasets.
+ * The 2 writing patterns are:
+ * 1. Random--chunks are wriitten in the random order.
+ * 2. ByRow--chunks are written by row order.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "../Perf/h5slab.h"
+#include "hdf5.h"
+
+/* Write the chunks in the row order. This provides good and bad read
+ * performance if the read pattern is by row and by column respectively.
+ *
+ * Created by Albert Cheng and Christian Chilan 2010/7/13.
+ */
+int
+createfilebyrow(void)
+{
+ hid_t file_id, dset_id, filespace, memspace, fapl, dxpl, dcpl;
+ hsize_t dimsf[2], count[2], offset[2], chunk_dims[2] = {CX, CY};
+ char *data, dataval, table[RC];
+ unsigned long i, j, l, cx;
+ fapl = H5Pcreate(H5P_FILE_ACCESS);
+ dcpl = H5Pcreate(H5P_DATASET_CREATE);
+ dxpl = H5Pcreate(H5P_DATASET_XFER);
+ H5Pset_chunk(dcpl, 2, chunk_dims);
+ fapl = dxpl = H5P_DEFAULT;
+ file_id = H5Fcreate("row_alloc.h5", H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
+ dimsf[0] = NX;
+ dimsf[1] = NY;
+ filespace = H5Screate_simple(2, dimsf, NULL);
+ dset_id = H5Dcreate(file_id, "dataset1", H5T_NATIVE_CHAR, filespace, H5P_DEFAULT, dcpl, H5P_DEFAULT);
+ count[0] = CX;
+ count[1] = NY;
+ memspace = H5Screate_simple(2, count, NULL);
+
+ data = (char *)malloc(count[0] * count[1] * sizeof(char));
+
+ /* writing the whole chunked rows each time. */
+ for (l = 0; l < RC; l++) {
+
+ offset[0] = l * CX;
+ offset[1] = 0;
+
+ /* fill with values according to row number */
+ for (i = 0; i < count[0]; i++)
+ for (j = 0; j < count[1]; j++)
+ data[i * count[1] + j] = l;
+
+ H5Sselect_hyperslab(filespace, H5S_SELECT_SET, offset, NULL, count, NULL);
+ H5Dwrite(dset_id, H5T_NATIVE_CHAR, memspace, filespace, dxpl, data);
+ }
+
+ free(data);
+ H5Dclose(dset_id);
+ H5Sclose(filespace);
+ H5Sclose(memspace);
+ H5Pclose(dxpl);
+ H5Pclose(dcpl);
+ H5Pclose(fapl);
+ H5Fclose(file_id);
+ return 0;
+}
+
+/* Write the chunks in a random pattern. This provides a read performance
+ * worse than when the chunks are written and read in the same order, whether
+ * it is by row or by column.
+ *
+ * Created by Albert Cheng and Christian Chilan 2010/7/13.
+ */
+int
+createfilerandom(void)
+{
+ hid_t file_id, dset_id, filespace, memspace, fapl, dxpl, dcpl;
+ hsize_t dimsf[2], count[2], offset[2], chunk_dims[2] = {CX, CY};
+ char *data, table[RC][CC];
+ unsigned long i, j, cx, cy;
+ fapl = H5Pcreate(H5P_FILE_ACCESS);
+ dcpl = H5Pcreate(H5P_DATASET_CREATE);
+ dxpl = H5Pcreate(H5P_DATASET_XFER);
+ H5Pset_chunk(dcpl, 2, chunk_dims);
+ fapl = dxpl = H5P_DEFAULT;
+ file_id = H5Fcreate("random_alloc.h5", H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
+ dimsf[0] = NX;
+ dimsf[1] = NY;
+ filespace = H5Screate_simple(2, dimsf, NULL);
+ dset_id = H5Dcreate(file_id, "dataset1", H5T_NATIVE_CHAR, filespace, H5P_DEFAULT, dcpl, H5P_DEFAULT);
+ count[0] = CX;
+ count[1] = CY;
+ memspace = H5Screate_simple(2, count, NULL);
+ data = (char *)malloc(count[0] * count[1] * sizeof(char));
+
+ for (i = 0; i < RC; i++)
+ for (j = 0; j < CC; j++)
+ table[i][j] = 0;
+
+ for (i = 0; i < RC * CC; i++) {
+ do {
+ cx = rand() % RC;
+ cy = rand() % CC;
+ } while (table[cx][cy]);
+
+ for (j = 0; j < count[0] * count[1]; j++) {
+ data[j] = cx + cy;
+ }
+
+ table[cx][cy] = 1;
+
+ offset[0] = cx * CX;
+ offset[1] = cy * CY;
+
+ H5Sselect_hyperslab(filespace, H5S_SELECT_SET, offset, NULL, count, NULL);
+ H5Dwrite(dset_id, H5T_NATIVE_CHAR, memspace, filespace, dxpl, data);
+ }
+
+ free(data);
+ H5Dclose(dset_id);
+ H5Sclose(filespace);
+ H5Sclose(memspace);
+ H5Pclose(dxpl);
+ H5Pclose(dcpl);
+ H5Pclose(fapl);
+ H5Fclose(file_id);
+ return 0;
+}
+
+int
+main(int argc, char **argv)
+{
+ createfilebyrow();
+ createfilerandom();
+}