Having downloaded NetLogo [1] and played around with it for a while, I am unsure whether it will meet the needs of our modeling project.
- NetLogo is particularly aimed at modeling systems as they adapt over time. Agents in NetLogo continuously respond to each other’s decisions, resulting in an ever-changing environment. To a great extent, we are interested in modeling a system that will develop over time: at a farmers’ market, for example, a seller makes a decision (setting up a vendor station), a buyer makes a decision motivated by the seller’s decision (walking over to the vendor station), then another decision (whether or not to buy from the this particular vendor), etc. For these types of interactions, it is crucial to have a simulation program that effectively displays change over time in the system, showing how decisions by each agent impacts each following decision by other agents.
- NetLogo allows one to easily change the variables in the system. For example in the “Cooperation†(of cows) model contained in the NetLogo models library [2], meters representing initial number of cows, cooperative probability, reproduction cost, etc. can be adjusted with a click of a button. This is just what we need for our model. We would have a meter representing number of buyers, number of sellers, buying probabilities of each one, price constraints, etc.
- Having examined many of the models in the NetLogo model library, I am not sure that the program will allow for the level of complexity that we require. We need to have several groups of buyers, each of which has different characteristics and behaviors. The models contained in NetLogo’s library have about five adjustable parameters—our program would need many more. Though I don’t know that NetLogo cannot provide for this, I am skeptical because none of the provided models shows this type of control over the system, or a system with this degree of complexity.
It should be noted that I do not know the language that NetLogo uses; therefore, my ability to experiment with the program was limited. NetLogo does use a fairly simple programming language, but I did not find it a good use of my time to become familiar enough with it to be able to create my own models.
Conclusion: Though NetLogo may be the most widely-used agent based modeling program, I am skeptical that it will meet our needs. At this point in my research, I have found three programs that appear suitable for the models we want to create: RePast, Ascape, and the at-this-point-in-time only Japanese PlatBox. In order to be sure whether or not NetLogo belongs on this list, I would have to experiment with the program with its required language.