[Paraview] advice on saving outputs

[Mohammad Mirzadeh]

Hi guys,

I need a little bit of advice on how I'm outputting data. So far I have
been using a simple legacy VTK format and dumping my grid and all
sclaar/vectors into that single file. Basically I start with writing the
grid and then append as many as variables that I like to the file. This has
the problem that it was ascii and slow for large data sets, especially fro
a parallel code where the solver was taking only 5 sec but the IO was
around 20!!

So I want to turn into binary and I have learned how to output binary vtu
files. The issue is, since the cluster I'm working with has kill times (Max
24 hr) I also need to be able to save and resume my simulation. So, what I
do right now is dump my variables in binary form into a single file that
does not have any xml tag or anything -- just raw binary data. This is a
preferred method since when I want to resume, I do not need to parse the
xml code; I just read the bindary file and that's it. Besides, I save on
the grid information I'm writing to disk. For a 23M grid point, the grid
information (which basically is a quadtree saved as a
general unstructured grid with cell connectivity information etc) file is
about 1GB whereas my actual data is only about 150MB. In most cases my grid
does not change with time, so I really only need to save it once and that's
enough.

Now, the problem is, I want to be able to use or refer to these binary
files using the xml tags. Here are the questions:

1) Is this supported in .vtu format? How can I refer to a binary file
instead of dumping all the binary information in the file?
2) If this is not supported in .vtu, is it something xdmf can do? If so
how? Can you please point me to a tutorial?
3) Is there any plan or strategy that would be better than what I have in
mind right now? Please remember that retaining the raw binary format of the
files is a must for me (well I do not see convincing reasons to give up on
it, but if there is one, please let me know)

Thanks
Mohammad
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