A free educational Java framework for graph algorithms

Problem statement: In the teaching of graph theory algorithms it is important that students can experiment them on numerical instances in order to fully understand their logical meaning and to learn how they can be implemented. Approach: We developed an open source Java framework to help students in their approach to the study of graph algorithms. The framework was implemented so as to be portable and easy to use. In addition, we included a library that anyone can easily use to develop custom algorithms. Results: The framework, which is currently in use at the University of Bologna, and is available on-line, presently includes four basic algorithms in graph theory, for the solution the following problems: shortest spanning tree, shortest paths, maximum flow, and critical path. It includes an intuitive graphical user interface, and gives the users the possibility of performing a "step-by-step" execution. Conclusions: The presented Java framework constitutes a first step towards the implementation of didactical instruments for the teaching of graph theory. Future developments will also include a new major release and an implementation targeting the Microsoft. NET framework.