A new Mata class called abm_nw is now available from this GitHub repository. It is intended to help manage a network for Agent Based models. An Agent Based Model is a simulation in which agents, that each follow simple rules, interact with one another and thus produce a often surprising outcome at the macro level. The purpose of an ABM is to explore mechanisms through which actions of the individual agents add up to a macro outcome, by varying the rules that agents have to follow or varying with whom the agent can interact (i.e. varying the network).

Which agents can interact with one another is thus an important part of an ABM. The abm_nw class contains a set of functions that allows one to set up such a network, find neighbourhoods of node, and change the network. This requies Stata version 15. The class itself is defined in the abm_nw.mata file. The class can be imported and used in an agent based model by adding the line do abm_grid.mata to the .do file that defines the ABM. There is a complete example of a simple ABM using abm_nw in the help files, start with help abm_nw.

There is also a "sister" class abm_grid, available here, that does a similar task for when the agents in the agent based model are placed on a square grid, like a chess board.