Lpp python script - post processing

Submitted by Kathy on Fri, 11/22/2019 - 19:03

Hello All,
I have installed CFDEM coupling and it works perfectly. Using octave we can get all results but there is a problem when the shell reads the following line in the post processing

#- get VTK data from liggghts dump file
cd $casePath/DEM/post
python -i $CFDEM_LPP_DIR/lpp.py dump.liggghts_run

this line will be executed and the conversion to VTK will occurs but the code stalls on this line and does not return to execute the rest of the shell (go to CFD/fomeToVTK folder and open paraview, or etc..)

Here is the output of this line and where everything stops ...

starting LIGGGHTS memory optimized parallel post processing
chunksize: 8 --> 8 files are processed per chunk. If you run out of memory reduce chunksize.
Working with 96 processes...
calculating chunks 1 - 1 of 1
wrote 1 granular snapshots in VTK format
time needed: 0.200386047363 sec
>>>

Any idea why this happens? Any help to debug that will be very much appreciated.

Forums:

Open DEM Japan | Mon, 11/03/2025 - 07:11

There have been many reports that LPP no longer works reliably on modern environments.
LPP was developed for Python 2 and is based on the older Pizza.py toolkit; as a result, it often runs into compatibility issues and bugs on systems where Python 3 is the default (e.g., Ubuntu 20.04+).
If your goal is converting LIGGGHTS dump files to VTK, I have developed a new program in Python 3:

Highlights

  • Includes an easy-to-use GUI; can also be used as a CLI for batch workflows.
  • Converts not only particle data to VTK, but also force chains.
  • Supports force-chain analysis using the Louvain method for community detection.

Please give it a try and feel free to share feedback or report issues on GitHub.