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hdf5/examples/h5_select.c
Raymond Lu e3a137f39e [svn-r4517] 
Purpose:
    Changed to the new generic property list for dataset creation property
    list.
Platforms tested:
    Arabica, modi4 and Hawkwind
2001-10-03 12:57:56 -05:00

318 lines
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/*
* This program shows how the H5Sselect_hyperslab and H5Sselect_elements
* functions are used to write selected data from memory to the file.
* Program takes 48 elements from the linear buffer and writes them into
* the matrix using 3x2 blocks, (4,3) stride and (2,4) count.
* Then four elements of the matrix are overwritten with the new values and
* file is closed. Program reopens the file and selects the union of two
* hyperslabs in the dataset in the file. Then it reads the selection into the
* memory dataset preserving the shape of the selection.
*/
#include "hdf5.h"
#define H5FILE_NAME "Select.h5"
#define MSPACE1_RANK 1 /* Rank of the first dataset in memory */
#define MSPACE1_DIM 50 /* Dataset size in memory */
#define MSPACE2_RANK 1 /* Rank of the second dataset in memory */
#define MSPACE2_DIM 4 /* Dataset size in memory */
#define FSPACE_RANK 2 /* Dataset rank as it is stored in the file */
#define FSPACE_DIM1 8 /* Dimension sizes of the dataset as it is
stored in the file */
#define FSPACE_DIM2 12
/* We will read dataset back from the file
to the dataset in memory with these
dataspace parameters. */
#define MSPACE_RANK 2
#define MSPACE_DIM1 8
#define MSPACE_DIM2 9
#define NPOINTS 4 /* Number of points that will be selected
and overwritten */
int
main (void)
{
hid_t file, dataset; /* File and dataset identifiers */
hid_t mid1, mid2, mid, fid; /* Dataspace identifiers */
hid_t plist; /* Dataset property list identifier */
hsize_t dim1[] = {MSPACE1_DIM}; /* Dimension size of the first dataset
(in memory) */
hsize_t dim2[] = {MSPACE2_DIM}; /* Dimension size of the second dataset
(in memory */
hsize_t fdim[] = {FSPACE_DIM1, FSPACE_DIM2};
/* Dimension sizes of the dataset (on disk) */
hsize_t mdim[] = {MSPACE_DIM1, MSPACE_DIM2}; /* Dimension sizes of the
dataset in memory when we
read selection from the
dataset on the disk */
hssize_t start[2]; /* Start of hyperslab */
hsize_t stride[2]; /* Stride of hyperslab */
hsize_t count[2]; /* Block count */
hsize_t block[2]; /* Block sizes */
hssize_t coord[NPOINTS][FSPACE_RANK]; /* Array to store selected points
from the file dataspace */
herr_t ret;
unsigned i,j;
int fillvalue = 0; /* Fill value for the dataset */
int matrix_out[MSPACE_DIM1][MSPACE_DIM2]; /* Buffer to read from the
dataset */
int vector[MSPACE1_DIM];
int values[] = {53, 59, 61, 67}; /* New values to be written */
/*
* Buffers' initialization.
*/
vector[0] = vector[MSPACE1_DIM - 1] = -1;
for (i = 1; i < MSPACE1_DIM - 1; i++) vector[i] = i;
/*
* Create a file.
*/
file = H5Fcreate(H5FILE_NAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/*
* Create property list for a dataset and set up fill values.
*/
plist = H5Pcreate(H5P_DATASET_CREATE);
ret = H5Pset_fill_value(plist, H5T_NATIVE_INT, &fillvalue);
/*
* Create dataspace for the dataset in the file.
*/
fid = H5Screate_simple(FSPACE_RANK, fdim, NULL);
/*
* Create dataset in the file. Notice that creation
* property list plist is used.
*/
dataset = H5Dcreate(file, "Matrix in file", H5T_NATIVE_INT, fid, plist);
/*
* Select hyperslab for the dataset in the file, using 3x2 blocks,
* (4,3) stride and (2,4) count starting at the position (0,1).
*/
start[0] = 0; start[1] = 1;
stride[0] = 4; stride[1] = 3;
count[0] = 2; count[1] = 4;
block[0] = 3; block[1] = 2;
ret = H5Sselect_hyperslab(fid, H5S_SELECT_SET, start, stride, count, block);
/*
* Create dataspace for the first dataset.
*/
mid1 = H5Screate_simple(MSPACE1_RANK, dim1, NULL);
/*
* Select hyperslab.
* We will use 48 elements of the vector buffer starting at the second element.
* Selected elements are 1 2 3 . . . 48
*/
start[0] = 1;
stride[0] = 1;
count[0] = 48;
block[0] = 1;
ret = H5Sselect_hyperslab(mid1, H5S_SELECT_SET, start, stride, count, block);
/*
* Write selection from the vector buffer to the dataset in the file.
*
* File dataset should look like this:
* 0 1 2 0 3 4 0 5 6 0 7 8
* 0 9 10 0 11 12 0 13 14 0 15 16
* 0 17 18 0 19 20 0 21 22 0 23 24
* 0 0 0 0 0 0 0 0 0 0 0 0
* 0 25 26 0 27 28 0 29 30 0 31 32
* 0 33 34 0 35 36 0 37 38 0 39 40
* 0 41 42 0 43 44 0 45 46 0 47 48
* 0 0 0 0 0 0 0 0 0 0 0 0
*/
ret = H5Dwrite(dataset, H5T_NATIVE_INT, mid1, fid, H5P_DEFAULT, vector);
/*
* Reset the selection for the file dataspace fid.
*/
ret = H5Sselect_none(fid);
/*
* Create dataspace for the second dataset.
*/
mid2 = H5Screate_simple(MSPACE2_RANK, dim2, NULL);
/*
* Select sequence of NPOINTS points in the file dataspace.
*/
coord[0][0] = 0; coord[0][1] = 0;
coord[1][0] = 3; coord[1][1] = 3;
coord[2][0] = 3; coord[2][1] = 5;
coord[3][0] = 5; coord[3][1] = 6;
ret = H5Sselect_elements(fid, H5S_SELECT_SET, NPOINTS,
(const hssize_t **)coord);
/*
* Write new selection of points to the dataset.
*/
ret = H5Dwrite(dataset, H5T_NATIVE_INT, mid2, fid, H5P_DEFAULT, values);
/*
* File dataset should look like this:
* 53 1 2 0 3 4 0 5 6 0 7 8
* 0 9 10 0 11 12 0 13 14 0 15 16
* 0 17 18 0 19 20 0 21 22 0 23 24
* 0 0 0 59 0 61 0 0 0 0 0 0
* 0 25 26 0 27 28 0 29 30 0 31 32
* 0 33 34 0 35 36 67 37 38 0 39 40
* 0 41 42 0 43 44 0 45 46 0 47 48
* 0 0 0 0 0 0 0 0 0 0 0 0
*
*/
/*
* Close memory file and memory dataspaces.
*/
ret = H5Sclose(mid1);
ret = H5Sclose(mid2);
ret = H5Sclose(fid);
/*
* Close dataset.
*/
ret = H5Dclose(dataset);
/*
* Close the file.
*/
ret = H5Fclose(file);
/*
* Open the file.
*/
file = H5Fopen(H5FILE_NAME, H5F_ACC_RDONLY, H5P_DEFAULT);
/*
* Open the dataset.
*/
dataset = H5Dopen(file,"Matrix in file");
/*
* Get dataspace of the open dataset.
*/
fid = H5Dget_space(dataset);
/*
* Select first hyperslab for the dataset in the file. The following
* elements are selected:
* 10 0 11 12
* 18 0 19 20
* 0 59 0 61
*
*/
start[0] = 1; start[1] = 2;
block[0] = 1; block[1] = 1;
stride[0] = 1; stride[1] = 1;
count[0] = 3; count[1] = 4;
ret = H5Sselect_hyperslab(fid, H5S_SELECT_SET, start, stride, count, block);
/*
* Add second selected hyperslab to the selection.
* The following elements are selected:
* 19 20 0 21 22
* 0 61 0 0 0
* 27 28 0 29 30
* 35 36 67 37 38
* 43 44 0 45 46
* 0 0 0 0 0
* Note that two hyperslabs overlap. Common elements are:
* 19 20
* 0 61
*/
start[0] = 2; start[1] = 4;
block[0] = 1; block[1] = 1;
stride[0] = 1; stride[1] = 1;
count[0] = 6; count[1] = 5;
ret = H5Sselect_hyperslab(fid, H5S_SELECT_OR, start, stride, count, block);
/*
* Create memory dataspace.
*/
mid = H5Screate_simple(MSPACE_RANK, mdim, NULL);
/*
* Select two hyperslabs in memory. Hyperslabs has the same
* size and shape as the selected hyperslabs for the file dataspace.
*/
start[0] = 0; start[1] = 0;
block[0] = 1; block[1] = 1;
stride[0] = 1; stride[1] = 1;
count[0] = 3; count[1] = 4;
ret = H5Sselect_hyperslab(mid, H5S_SELECT_SET, start, stride, count, block);
start[0] = 1; start[1] = 2;
block[0] = 1; block[1] = 1;
stride[0] = 1; stride[1] = 1;
count[0] = 6; count[1] = 5;
ret = H5Sselect_hyperslab(mid, H5S_SELECT_OR, start, stride, count, block);
/*
* Initialize data buffer.
*/
for (i = 0; i < MSPACE_DIM1; i++) {
for (j = 0; j < MSPACE_DIM2; j++)
matrix_out[i][j] = 0;
}
/*
* Read data back to the buffer matrix_out.
*/
ret = H5Dread(dataset, H5T_NATIVE_INT, mid, fid,
H5P_DEFAULT, matrix_out);
/*
* Display the result. Memory dataset is:
*
* 10 0 11 12 0 0 0 0 0
* 18 0 19 20 0 21 22 0 0
* 0 59 0 61 0 0 0 0 0
* 0 0 27 28 0 29 30 0 0
* 0 0 35 36 67 37 38 0 0
* 0 0 43 44 0 45 46 0 0
* 0 0 0 0 0 0 0 0 0
* 0 0 0 0 0 0 0 0 0
*/
for (i=0; i < MSPACE_DIM1; i++) {
for(j=0; j < MSPACE_DIM2; j++) printf("%3d ", matrix_out[i][j]);
printf("\n");
}
/*
* Close memory file and memory dataspaces.
*/
ret = H5Sclose(mid);
ret = H5Sclose(fid);
/*
* Close dataset.
*/
ret = H5Dclose(dataset);
/*
* Close property list
*/
ret = H5Pclose(plist);
/*
* Close the file.
*/
ret = H5Fclose(file);
return 0;
}
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