Software written By Frans

While I was working in the computational chemistry group, we used a lot of software and I have written quite a few lines for our specific purposes. Some of this software is available in the public domain.


Grovi

Grovi is a powerful and very fast program to visualize large molecules using high quality rendering. It is capable of showing the movements of the atoms as calculated by molecular simulations programs such as the GroMacs program mentioned above and visualize the results of analysis in real time.

The final program will be truly amazing as it will allow true interactive interaction with running simulations. Allowing to change parameters in the simulation and get real time results from the simulation and the analysis programs. This involves clever algorithmes and some good psychology so people get new feedback from simulations at least once every six seconds. Currently normal molecular simulations may take days to produce output.

The first step is the delivery of 'grovi light'. This will be a viewer for molecules in general and a viewer to see the molecules move in time. Currently there is at least a dozen of programs around that allows you to do just that, but grovi already runs at least 10 times faster for showing large molecules in ball & stick model. And the balls are of much higher quality. Also most people want to make a video at some point to present their results. This is a very time consuming and very user unfriendly process in the existing programs. Grovi light comes (perhaps not in the very first version, but at least soon afterwards) with a extremely userfriendly animation tool, based on what animation artists use in other programs, but this is not yet seen in molecular visualisation programs.

Grovi is not yet available, but the light version is expected to be ready in the second half of 2000.

Unfortunatly, my professor retired, and the one who took over his job doesn't want people to work on visualisation at all. So work on Grovi stopped in january 2000. This is one of the reasons I changed my job.

Europort data compression

This software was written to facilitate compression of trajectory data and to make a binary format that is portable between different machines. This goal was achieved by writing a highly specific (and therefore efficient) compression algorithm on top of the XDR library. This library is generally used for nfs transport and should be available on any workstation or supercomputer. The compression rate is about 70% (The compressed trajectory data takes only about 30% of the original), but this can be tuned for specific purposes.

Read more about this algorithm, including download instructions from the Europort data compression page.




Time evolution of phase separation. Time runs from bottom to top.

3dMovie

This is a hack that allows you to display the time evolution of data. The 'normal' way of doing this is to make a movie and show that. However if the data is periodic in space (so called periodic boundary conditions) we can combine one of the spacial axis with the time axis by taking small slices of the data and move the slice through space as time increases. One example of such an approach is shown on the left. Normaly you would need a movie to show the change in time and see the tubes appear, now you can see it happen in a single image. Please click on the image to get a larger version of it with much more detail. This method works very well for 2d as well as 3d data. The 3dmovie program is written to accept as input files produced by MesoDyn, but as the algorithm is pretty simple it can easily be adapted to accept other data.

The idea for this new type of visualisation came from Frans van Hoesel, who also wrote the little program. If you want to use it for your data, feel free to copy the source 3dmovie.c.