Hi,
I am new to compound type and am learning it using the following as
a reference
http://www.hdfgroup.org/ftp/HDF5/examples/examples-by-api/hdf5-examples/1_8/C/H5T/h5ex_t_cmpd.c
I did build an ran the example and it produce the expected result.
Using the above, I tried creating my own compound type; a vector of
x,y,z but my data is always '0'
I have include the source code and the h5dump output in this posting.
I'd like to know where I have gone wrong.
Kind regards
== h5dump of file ==
HDF5 "vertex_compound.h5" {
GROUP "/" {
DATASET "vertices" {
DATATYPE H5T_COMPOUND {
H5T_IEEE_F32LE "x";
H5T_IEEE_F32LE "y";
H5T_IEEE_F32LE "z";
}
DATASPACE SIMPLE { ( 4 ) / ( 4 ) }
DATA {
(0): {
0,
0,
0
},
(1): {
0,
0,
0
},
(2): {
0,
0,
0
},
(3): {
0,
0,
0
}
}
}
}
}
== source code ==
#include "hdf5.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
const char dataset_name[] = "vertices";
const hsize_t DIM0=4;
const size_t RANK_OUT = 1;
const size_t NX_SUB = 1; // Number of vertices to read in
const size_t NX = 1; // Number of vertices to read in
const size_t NY = 3; // Number of scalar e.g. x,y,z i.e. 3
typedef struct {
float x;
float y;
float z;
} v3f_t; /* Compound type */
void write_file(const char* filename)
{
hid_t file, filetype, memtype, space, dset;
/* Handles */
herr_t status;
hsize_t dims[1] = {DIM0};
v3f_t wdata[DIM0]; /* Write buffer */
/*
* Initialize data.
*/
wdata[0].x = 0.0;
wdata[0].y = 1.0;
wdata[0].z = 2.0;
wdata[1].x = 3.0;
wdata[1].y = 4.0;
wdata[1].z = 5.0;
wdata[2].x = 6.0;
wdata[2].y = 7.0;
wdata[2].z = 8.0;
wdata[3].x = 9.0;
wdata[3].y = 10.0;
wdata[3].z = 11.0;
/*
* Create a new file using the default properties.
*/
file = H5Fcreate (filename, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
/*
* Create the compound datatype for memory.
*/
memtype = H5Tcreate (H5T_COMPOUND, sizeof (v3f_t));
status = H5Tinsert (memtype, "x coordinate",
HOFFSET (v3f_t, x), H5T_NATIVE_FLOAT);
status = H5Tinsert (memtype, "y coordinate",
HOFFSET (v3f_t, y), H5T_NATIVE_FLOAT);
status = H5Tinsert (memtype, "z coordinate",
HOFFSET (v3f_t, z), H5T_NATIVE_FLOAT);
/*
* Create the compound datatype for the file. Because the standard
* types we are using for the file may have different sizes than
* the corresponding native types, we must manually calculate the
* offset of each member.
*/
filetype = H5Tcreate (H5T_COMPOUND, 4 + 4 + 4);
status = H5Tinsert (filetype, "x", 0, H5T_IEEE_F32LE);
status = H5Tinsert (filetype, "y", 4, H5T_IEEE_F32LE);
status = H5Tinsert (filetype, "z", 8, H5T_IEEE_F32LE);
/*
* Create dataspace. Setting maximum size to NULL sets the maximum
* size to be the current size.
*/
space = H5Screate_simple (1, dims, NULL);
/*
* Create the dataset and write the compound data to it.
*/
dset = H5Dcreate (file, dataset_name, filetype, space, H5P_DEFAULT,
H5P_DEFAULT,
H5P_DEFAULT);
status = H5Dwrite (dset, memtype, H5S_ALL, H5S_ALL, H5P_DEFAULT,
wdata);
/*
* Close and release resources.
*/
status = H5Dclose (dset);
status = H5Sclose (space);
status = H5Tclose (filetype);
status = H5Fclose (file);
}
int main (void)
{
char filename[] = "vertex_compound.h5";
write_file(filename);
return 0;
}
Cheers
--
Nicholas Yue
Graphics - RenderMan, Visualization, OpenGL, HDF5
Custom Dev - C++ porting, OSX, Linux, Windows
http://au.linkedin.com/in/nicholasyue
https://vimeo.com/channels/naiadtools
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