netlogo

NetLogo is a cross-platform environment for simulating natural and social phenomena with agent-based models. It provides a dedicated programming language and a visual interface that makes it easy to model decentralized systems composed of autonomous agents, such as turtles, patches, and links.

Originally derived from StarLogo, NetLogo was developed at Northwestern University by Uri Wilensky and first released in the late 1990s. It runs on Java and is available for Windows, macOS, and Linux. NetLogo is free and open-source software, and it includes a large library of ready-made models used in education and research.

The NetLogo language is domain-specific and works with two types of agents (turtles, patches) and optional links. Programs use procedures starting with "to" and ending with "end", and the "ask" construct to command agents. The world is a grid-based 2D environment by default, with an optional 3D mode in NetLogo 3D. The language supports control structures, mathematics, random number generation, and extensions.

NetLogo provides tools such as BehaviorSpace for automated experiments, a model library, a debugger, and a 3D view in NetLogo 3D. It also includes NetLogo Web for browser-based models and extensions for GIS and data handling. Models can be exported and shared as .nlogo files, and results can be exported to CSV.

NetLogo is widely used in education to illustrate complex systems and in research to prototype agent-based models in ecology, epidemiology, social science, economics, and urban studies. Notable models include Schelling segregation and Wolf Sheep Predation. The platform emphasizes accessibility, reproducibility, and a community-driven repository of models.