John David Eriksen
john DOT eriksen AT yahoo DOT com
http://www.jkndrkn.com

Overview:

An Erlang implementation of the T-Man algorithm detailed in the paper "T-Man: Gossip-based Overlay Topology Management" by Jelasity and Babaoglu. The network is conceptualized as nodes represented as vertices within a two-dimensional grid.

This implementation of the T-Man algorithm contained in the file tman.erl is able to successfully build a network with a sum of distances substantially lower than that of a purely random system (see plot-1.png and distances.dat).  The most dramatic changes happened in the first five generations, with only a very gradual improvement in sum of distances occurring after that interval.

These results are illustrated graphically in a series of image renderings of the mesh network (see GIF images in graphs directory). Note how the long and chaotic edges in the first generation gradually yield to a nearly perfectly converged grid-like mesh in subsequent generations. 

Usage:

1. Start the Erlang shell.
$ erl

2. Compile the source code.
> c(tman).

3. Run the T-Man algorithm with parameters Nodes = 900, Neighbors = 20, Cycles = 50, Size = 30 x 30.
> tman:init().

4. Run the T-Man algorithm user-specified nodes N and neighbors k
> tman:init(N,k).

5. Exit the Erlang shell.
> q().

File Listing:

distances.dat   Raw output generated by running T-Man algorithm with parameters as in Usage step 3.
graphs          Directory containing graphs generated by running T-Man algorithm using function init/5 with GraphOutput parameter true. 
Makefile        GNU Make Makefile. Provided here simply for cleaning up unneeded binaries. 
plot-1.png      Plot generated by gnuplot using distances.dat data file.
plot-data.gnu   gnuplot script used for generating plot-1.png.
tman.erl        Project source code.
tman.hrl        Project header file containing constant and macro definitions and the Erlang record definition of a node structure.

Dependencies:

To generate the images used by graphs, ImageMagick needs to be available. gnuplot or any other graphing software can be used to plot the raw distance output of this program.