Hi,
I was digging around a little bit to get the default behavior of HDF5 when using MPI IO.
I tried with and without setting H5Pset_fill_time(h5p, H5D_FILL_TIME_NEVER) for chunked and continuous variables.
There is no difference in the called MPI functions and the datasets contain zeros in both cases (according to h5dump).
Does H5Pset_fill_time make a difference when MPI IO is used?
Thanks,
Sebastian
···
--
Sebastian Rettenberger, M.Sc.
Technische Universität München
Department of Informatics
Chair of Scientific Computing
Boltzmannstrasse 3, 85748 Garching, Germany
http://www5.in.tum.de/
By default the fill value is zero (see
http://www.hdfgroup.org/HDF5/doc/RM/RM_H5P.html#Property-SetFillValue) so you
may want to set it to another value to test this feature.
HTH,
Pierre
···
On Tue, Oct 21, 2014 at 07:02:08PM +0200, Sebastian Rettenberger wrote:
I was digging around a little bit to get the default behavior of
HDF5 when using MPI IO.
I tried with and without setting H5Pset_fill_time(h5p,
H5D_FILL_TIME_NEVER) for chunked and continuous variables.
There is no difference in the called MPI functions and the datasets
contain zeros in both cases (according to h5dump).
Does H5Pset_fill_time make a difference when MPI IO is used?
Thanks, after some more testing and reading through the documentation again, I found this sentence:
H5D_FILL_TIME_IFSET Write fill values to the dataset when storage space is allocated only if there is a user-defined fill value, i.e., one set with H5Pset_fill_value. (Default)
My first interpretation was, that the fill value is written if it is defined. However, it is only written if it is defined and not the default value.
Thanks again,
Sebastian
···
On 21.10.2014 21:13, pierre.debuyl@chem.kuleuven.be wrote:
On Tue, Oct 21, 2014 at 07:02:08PM +0200, Sebastian Rettenberger wrote:
I was digging around a little bit to get the default behavior of
HDF5 when using MPI IO.
I tried with and without setting H5Pset_fill_time(h5p,
H5D_FILL_TIME_NEVER) for chunked and continuous variables.
There is no difference in the called MPI functions and the datasets
contain zeros in both cases (according to h5dump).
Does H5Pset_fill_time make a difference when MPI IO is used?
By default the fill value is zero (see
http://www.hdfgroup.org/HDF5/doc/RM/RM_H5P.html#Property-SetFillValue) so you
may want to set it to another value to test this feature.
HTH,
Pierre
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--
Sebastian Rettenberger, M.Sc.
Technische Universität München
Department of Informatics
Chair of Scientific Computing
Boltzmannstrasse 3, 85748 Garching, Germany
http://www5.in.tum.de/
