[vtkusers] different behavior between ascii and binary ensight gold reader

[Utkarsh Ayachit]

Thanks for the detailed bug report Georg, we'll take a look at it soon.

Utkarsh

On Wed, Mar 6, 2013 at 4:23 AM, Georg Hammerl <hammerl at lnm.mw.tum.de> wrote:
> Hello,
>
> I have already posted this issue on the paraview mailing list, but then I
> realized that it is more of a VTK problem.
> I can load the first time step of my results but when I switch to the next
> step (in which 4 points are added), paraview freezes and htop shows 100%
> load for this process. Surprisingly, this only happens when I use binary
> ensight gold format. The same results written in ascii ensight gold format
> work. The ens_checker tells me for both cases that I have valid output
> files.
>
> Meanwhile I had a look into the source code and discovered the issue.
> Whenever the variable-files are read for a time steps greater than 1,
> Paraview has to jump in the binary file to the desired timestep. This is
> done by partially parsing and skipping blocks until the correct "BEGIN TIME
> STEP" is found. In order to skip the correct block length, Paraview uses the
> number of points (numPts) from the current geometry step. This breaks with a
> varying number of points per timestep.
> As an example my first step contains 2 points and the second step 6 points,
> therefore when Paraview skips the first time step, it skips a block length
> equivalent to 6 points. The correct number would be 2 points. It therefore
> skips past the next "BEGIN TIME STEP".
>
> In order to verify my theory I have implemented a little hack which looks
> for the next "BEGIN TIME STEP" by brute force. In case someone wants to try
> this I have attached a patch which can be used in conjunction with the
> attached examples.
>
> A clean solution would be to skip the correct number of points for every
> given timestep. Unfortunately I do not have enough insight into the VTK
> ensight reader to implement this and would appreciate any help in finding a
> clean solution to this.
>
> Cheers,
>
> Georg
>
> --
> Dipl.-Ing. Georg Hammerl
> Lehrstuhl für Numerische Mechanik
> Technische Universität München
> Boltzmannstrasse 15, D-85747 Garching b. München
> phone +49 89 289 15237
> fax +49 89 289 15301
> hammerl at lnm.mw.tum.de
> http://www.lnm.mw.tum.de
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers
>