<div dir="ltr">If it is possible to generate the index files as post-processing step, then I would prefer that, as it reduces the time the simulation spends waiting for I/O. We could add it e.g. to Simfactory's cleanup step to have it happen automatically.<div>
<br></div><div style>How well-documented are the index files? If they are generated by default, then there should be a section in CarpetIOHDF5's thorn guide (or in the Visit reader's documentation) describing why they are a good idea, and what information they contain, and how they can be used to speed up input.</div>
<div style><br></div><div style>-erik</div><div style><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Feb 27, 2013 at 2:41 PM, Roland Haas <span dir="ltr"><<a href="mailto:roland.haas@physics.gatech.edu" target="_blank">roland.haas@physics.gatech.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello all,<br>
<div class="im"><br>
> Would somebody object to making CarpetIOHDF5::output_index = "yes" the<br>
> default? (It is currently "no".)<br>
><br>
> It should not hurt to create these small files. (Or, does it?)<br>
</div>It creates files which in itself might be bad. Creating files can be an<br>
issue on some file systems where creating files is slow (or there might<br>
be limit on the number of files, that apparently on some clusters<br>
[admittedly I know of no Cactus users there] can be as low as 1e6 files<br>
*total*).<br>
<br>
Also currently there is a bug/mis-feature in that output_index writes<br>
indices for both data and checkpoint files. The later probably should<br>
have a separate switch since index files are less useful there.<br>
<br>
If the issue is that we currently have no method for users to create<br>
index files for existing HDF5 files once eg they find that visualization<br>
is slow, then for that I have a modified version of hdf5_merge (or was<br>
it hdf5_extract... anyway one of them) where I simply commented out the<br>
final H5Dwrite and which generates perfectly fine index files (of the<br>
"new" format that do not have the extra attribute with just that change<br>
or "old" ones with the attribute with the obvious changes [that are also<br>
in]). It's of course a bit of a hack since the tools were not originally<br>
meant to do that.<br>
<br>
Yours,<br>
Roland<br>
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</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br>Erik Schnetter <<a href="mailto:schnetter@cct.lsu.edu" target="_blank">schnetter@cct.lsu.edu</a>><br><a href="http://www.perimeterinstitute.ca/personal/eschnetter/" target="_blank">http://www.perimeterinstitute.ca/personal/eschnetter/</a>
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