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/************************************************************
This example shows how to read and write float datatypes
to a dataset. The program first writes floats to a
dataset with a dataspace of DIM0xDIM1, then closes the
file. Next, it reopens the file, reads back the data, and
outputs it to the screen.
************************************************************/
#include "hdf5.h"
#include <stdio.h>
#include <stdlib.h>
#define FILE "h5ex_t_float.h5"
#define DATASET "DS1"
#define DIM0 4
#define DIM1 7
int
main(void)
{
hid_t file, space, dset; /* Handles */
herr_t status;
hsize_t dims[2] = {DIM0, DIM1};
double wdata[DIM0][DIM1], /* Write buffer */
**rdata; /* Read buffer */
int ndims;
hsize_t i, j;
/*
* Initialize data.
*/
for (i = 0; i < DIM0; i++)
for (j = 0; j < DIM1; j++)
wdata[i][j] = (double)i / (j + 0.5) + j;
/*
* Create a new file using the default properties.
*/
file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/*
* Create dataspace. Setting maximum size to NULL sets the maximum
* size to be the current size.
*/
space = H5Screate_simple(2, dims, NULL);
/*
* Create the dataset and write the floating point data to it. In
* this example we will save the data as 64 bit little endian IEEE
* floating point numbers, regardless of the native type. The HDF5
* library automatically converts between different floating point
* types.
*/
dset = H5Dcreate(file, DATASET, H5T_IEEE_F64LE, space, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
status = H5Dwrite(dset, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata[0]);
/*
* Close and release resources.
*/
status = H5Dclose(dset);
status = H5Sclose(space);
status = H5Fclose(file);
/*
* Now we begin the read section of this example. Here we assume
* the dataset has the same name and rank, but can have any size.
* Therefore we must allocate a new array to read in data using
* malloc().
*/
/*
* Open file and dataset.
*/
file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);
dset = H5Dopen(file, DATASET, H5P_DEFAULT);
/*
* Get dataspace and allocate memory for read buffer. This is a
* two dimensional dataset so the dynamic allocation must be done
* in steps.
*/
space = H5Dget_space(dset);
ndims = H5Sget_simple_extent_dims(space, dims, NULL);
/*
* Allocate array of pointers to rows.
*/
rdata = (double **)malloc(dims[0] * sizeof(double *));
/*
* Allocate space for floating point data.
*/
rdata[0] = (double *)malloc(dims[0] * dims[1] * sizeof(double));
/*
* Set the rest of the pointers to rows to the correct addresses.
*/
for (i = 1; i < dims[0]; i++)
rdata[i] = rdata[0] + i * dims[1];
/*
* Read the data.
*/
status = H5Dread(dset, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata[0]);
/*
* Output the data to the screen.
*/
printf("%s:\n", DATASET);
for (i = 0; i < dims[0]; i++) {
printf(" [");
for (j = 0; j < dims[1]; j++)
printf(" %6.4f", rdata[i][j]);
printf("]\n");
}
/*
* Close and release resources.
*/
free(rdata[0]);
free(rdata);
status = H5Dclose(dset);
status = H5Sclose(space);
status = H5Fclose(file);
return 0;
}
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