How to indicate invalid values in HDF5 tables

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1

Hello,

Is there a recommended way to indicate whether a field in a record of
a table is invalid? For example, for double's, I could use NaN. But
that does not work if I actually want to store a NaN. Also, I need
something that works for everything: strings, bools, etc. I could do
it by adding a char array column and checking the bit corresponding to
a column. It is a bit clunky, and I want to make sure I am not
reinventing the wheel.

Thanks,
Walter Landry

2

Hi Walter,

···

On Feb 20, 2015, at 4:28 PM, Walter Landry <wlandry@caltech.edu> wrote:

Hello,

Is there a recommended way to indicate whether a field in a record of
a table is invalid? For example, for double's, I could use NaN. But
that does not work if I actually want to store a NaN. Also, I need
something that works for everything: strings, bools, etc. I could do
it by adding a char array column and checking the bit corresponding to
a column. It is a bit clunky, and I want to make sure I am not
reinventing the wheel.

Unfortunately, there is no way in HDF5 to indicate an invalid value in a dataset.

We saw HDF5 files where a dataset with 8-bit “quality flags” was stored along with the original (numeric) dataset to indicate the valid elements. Since it contained mostly 1 and 0, it compressed well and didn’t create much storage overhead.

Elena

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Elena Pourmal The HDF Group http://hdfgroup.org
1800 So. Oak St., Suite 203, Champaign IL 61820
217.531.6112
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Thanks,
Walter Landry

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