Introduction

This is a library which serves to simulate evolutions of graph configurations using Poisson Point process clocks which are put on every vertex.

Prerequisites and Installation

To use this library you will need make, pkg-config, glib-2.0, graphviz (such that the C pkg-config --libs pkg glib-2.0 libgvc). The commands in this section further use ffmpeg to convert frames to video and save the video/stream it to a video player (here mpv). This library has been used and tested on GNU/Linux based systems so no assurance is given that everything works on other systems.

Change directories into the download location of this library. Download the the C library of the PCG Pseudo Random Number Generator family (click me for download, unpack it into the lib subdirectory (resulting in a lib/pcg-c directory) and run make in it. Alternatively, change PCG_DIR in Makefile.am if you have already compiled this random number generator somewhere else. In this case you have to run autoreconf -i again which might install some extra files but ensures that your new your change to Makefile.am is respected in the further process.

Finally run

 ./configure && make

to compile this library. You can also run sudo make install to install the library and be able to execute the file from anywhere without having to specify the path to this library.

Usage

If you wish to run the simulation and save the final state of the configuration in a png (final.png), then run

 ./glauber_dynamics -q.

To have a comparison between the state after 10 iterations and the end of the simulation add the -i flag

 ./glauber_dynamics -qi.

To save the video file of the configuration evolution using ffmpeg for example use that ./glauber_dynamics streams png files to stdout and hence you can pipe the output to ffmpeg directly and save it for example in the nut format as out.nut by writing

 ./glauber_dynamics | ffmpeg -i pipe: -vf fps=100 -y -f nut out.nut

If you additionally want to concurrently stream the evolution while simulating specify an additional output to ffmpeg which pipes its rendered video to stdout and can thus be piped into any regular video player, here mpv, as

 ./glauber_dynamics | ffmpeg -i pipe: -vf fps=100 -y -f nut  pipe: -y -f nut out.nut| mpv -

Adapt the fps (frames per second) to your need. If you increase the frames per second you will have a shorter video but streaming it will be laggy as more frames have to be calculated for a second of output.

For detailed info on what options are available and the inline command-line options available to change the output run

 ./glauber_dynamics --help

Adapt code to personal use case and contributing

This code was written with the possibilty for future extension in mind. To use different update rules or write your own consult update_rules.h about details. Extending the available graphs is currently not as straightforward but not impossible. All graph related stuff has been isolated into the weightedgraph lib (cf. weightedgraph.h).

Contributions are always welcome but it is important that tests are added using the glib testing harness (for examples see for example test_weightedgraph.c. and the documentation of glib testing) and the entries in Makefile.am should be changed accordingly so that make check includes the new tests after the usual autoreconf. All code here should be in C11. If all these conditions are met a pull request is more than welcome.