Constraints on experimental design

There have been a number of constraints limiting the viable experimental conditions in the simulation. The largest of these is the limitations on memory. Allegro CL 5.0 Trial Edition, the lisp interpreter/compiler used for this project, has a heap limit of five megabytes, affecting the amount of agents that could be held in memory. This would not be a problem if all that was required was to remember the agents as they are living. Unfortunately, a number of the statistics require that the agents be kept for a certain time after they die, and this greatly increases the memory usage necessary. It is not appropriate here to write the data directly to file as the simulation writes all data to standard output. This is done so multiple simulations can be easily run on a cluster of computers.

Another consideration is running time. The running time for each cycle is linearly proportionate to the number of agents living that cycle. Simulations which contain two or three thousand agents might take one to two days to collect the results, while those which contain a few hundred complete within a number of hours.

These conditions served to restrict the amount of agents able to be used in experiments, this caused further problems, described in section 6.1.