Tests and Examples¶
The tests directory contains a few simple tests of the H5Z-ZFP filter some of which also serve as decent examples.
The test client, test_write.c
is compiled a couple of different ways.
One target is test_write_plugin
which demonstrates the use of this filter as
a standalone plugin. The other target, test_write_lib
, demonstrates the use
of the filter as an explicitly linked library. By default, these test a simple
1D array with and without ZFP compression using either the Generic Interface (for plugin)
or the Properties Interface (for library). You can use the code there as an
example of using the ZFP filter either as a plugin or as a library. However, these
also include some advanced usages for 4D and 6D, time-varying (e.g. extendable)
datasets. The command test_write_lib help
or test_write_plugin help
will print a
list of the example’s options and how to use them.
Write Test Options¶
./test/test_write_lib --help
ifile="" set input filename
ofile="test_zfp.h5" set output filename
1D dataset generation arguments...
npoints=1024 set number of points for 1D dataset
noise=0.001 set amount of random noise in 1D dataset
amp=17.7 set amplitude of sinusoid in 1D dataset
chunk=256 set chunk size for 1D dataset
doint=0 also do integer 1D data
ZFP compression parameters...
zfpmode=3 (1=rate,2=prec,3=acc,4=expert,5=reversible)
rate=4 set rate for rate mode of filter
acc=0 set accuracy for accuracy mode of filter
prec=11 set precision for precision mode of zfp filter
minbits=0 set minbits for expert mode of zfp filter
maxbits=4171 set maxbits for expert mode of zfp filter
maxprec=64 set maxprec for expert mode of zfp filter
minexp=-1074 set minexp for expert mode of zfp filter
Advanced cases...
highd=0 run 4D case
sixd=0 run 6D extendable case (requires ZFP>=0.5.4)
help=0 this help message
The test normally just tests compression of 1D array of integer
and double precision data of a sinusoidal array with a small
amount of additive random noise. The highd
test runs a test
on a 4D dataset where two of the 4 dimensions are not correlated.
This tests the plugin’s ability to properly set chunking for
HDF5 such that chunks span only correlated dimensions and
have non-unity sizes in 3 or fewer dimensions. The sixd
test runs a test on a 6D, extendable dataset representing an
example of using ZFP for compression along the time axis.
There is a companion, test_read.c
which is compiled into test_read_plugin
and test_read_lib
which demonstrates use of the filter reading data as a
plugin or library. Also, the commands test_read_lib help
and
test_read_plugin help
will print a list of the command line options.
To use the plugin examples, you need to tell the HDF5 library where to find the
H5Z-ZFP plugin with the HDF5_PLUGIN_PATH
environment variable. The value you
pass is the path to the directory containing the plugin shared library.
Finally, there is a Fortran test example, test_rw_fortran.F90. The Fortran test writes and reads a 2D dataset. However, the Fortran test is designed to use the filter only as a library and not as a plugin. The reason for this is that the filter controls involve passing combinations of integer and floating point data from Fortran callers and this can be done only through the Properties Interface, which by its nature requires any Fortran application to have to link with an implementation of that interface. Since we need to link extra code for Fortran, we may as well also link to the filter itself alleviating the need to use the filter as a plugin. Also, if you want to use Fortran support, the HDF5 library must have, of course, been configured and built with Fortran support as well.
In addition, a number tests are performed in the Makefile which test the plugin
by using some of the HDF5 tools such as h5dump
and h5repack
. Again, to
use these tools to read data compressed with the H5Z-ZFP filter, you will need
to inform the HDF5 library where to find the filter plugin. For example..
env HDF5_PLUGIN_PATH=<dir> h5ls test_zfp.h5
Where <dir>
is the relative or absolute path to a directory containing the
filter plugin shared library.