[Paraview] Performance of the CGNS Reader

[Mickael Philit]

Hello,

First, the CGNS reader coming through the VisItBridge is not working in 
parallel, it's a plain serial reader.
Second, there are limitations to the current cgns reader way of doing 
thing, since :
   - At the beginning, it parses the whole file (this takes a lot of 
time) to get variable names, blocks and so on, before actually reading 
the data.  [ I think that tecplot is cleaner because it seems to read 
the whole CGNS file in one pass ]
  - meshes are read in a temporary array and converted to a VTK vector 
of coordinates (thus memory manipulation)
  - for unstructured meshes, convertion from 'integer' to 'long' of 
cells connectivity eats memory.
The CGNS reader can improve but at the cost of redesining some parts to 
fit better in paraview and go for parallel.

Mickael


On 29/08/2013 16:50, Angelini, Richard C (Rick) CIV USARMY ARL (US) wrote:
> As a followup to this that may be related - does the CGNS reader through the VisItBridge work in parallel?    I've loaded up a couple of different CGNS datasets and then applied the ProcessIDScalars filter and it doesn't appear to be distributing the data - even multi-block CGNS files.
>
>
> ________________________________
> Rick Angelini
>
> USArmy Research Laboratory
> CISD/HPC Architectures Team
> Building 120 Cube 315
> Phone:  410-278-6266
>
> ________________________________________
> From: paraview-bounces at paraview.org [paraview-bounces at paraview.org] on behalf of Richard GRENON [richard.grenon at onera.fr]
> Sent: Thursday, August 29, 2013 10:38 AM
> To: paraview at paraview.org
> Subject: [Paraview]  Performance of the CGNS Reader
>
> Hello.
>
> I am testing the CGNS reader of Paraview 4.0.1 64 bits running on a
> Linux Workstation having 4 CPUs and 5.8 Gbytes of memory. Paraview was
> installed from the binaries available on the download page.
>
> I am trying to load a 1.36 Gbytes CGNS file that is available through
> the network.
>
> While loading this file, the Paraview Windows is frozen and cannot be
> refreshed, and I must check with the "ps" command on a terminal window
> or with a system monitor if PV  is still running or if it is really
> frozen. A progress bar for all readers would be welcome in a next release.
>
> Finally, the file can be loaded, but it always takes about 15 mn (+ or -
> 1 mn depending of the load of the network), while Tecplot always loads
> the same file within less that 1 mn !
>
> How do you explain this poor performance of the CGNS reader ? Can it be
> improved, or am I missing something ? Is there some Paraview option that
> could reduce loading time of large files ?
>
> Best regards
>
> --
>    Richard GRENON
>    ONERA
>    Departement d'Aerodynamique Appliquee - DAAP/ACI
>    8 rue des Vertugadins
>    92190 MEUDON - FRANCE
>    phone : +33 1 46 73 42 17
>    fax   : +33 1 46 73 41 46
>    mailto:Richard.Grenon at onera.fr
>    http://www.onera.fr
>
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