Re: [h5md-user] Variable-size particle groups

[Olaf Lenz]

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Hi!

On 05/29/2012 05:17 PM, Peter Colberg wrote:
> At any given timestep, each processor owns a defined set of 
> particles of varying number, which shall be written to an HDF5 
> dataset. The task that needs to be solved is to calculate for each 
> process the offset from the beginning of the “range” for the
> current time-step.
> 
> This could be done in parallel using a prefix sum [1].

Nah, the problem is not just knowing where to write in the file, but
that it may not change throughout the process.
The idea of parallel IO (with a distributed file system) is that a
single file is sliced up over several hard disks, so that each task just
has to write to its local disk. Otherwise, parallel IO wouldn't really
help, as the bottleneck is the IO speed of the hard disks.

Olaf
- -- 
Dr. rer. nat. Olaf Lenz
Institut für Computerphysik, Pfaffenwaldring 27, D-70569 Stuttgart
Phone: +49-711-685-63607
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