SimpleGraphs

We have made the following (breaking) changes:

• SimpleGraph has been renamed UndirectedGraph.
• SimpleDigraph has been renamed DirectedGraph.
• SimpleHypergraph has been renamed HyperGraph (note the captial G).

These may be abbreviated as UG, DG, and HG, respectively

These changes were made to help this SimpleGraphs module be interoperable with Julia's Graphs module that defines the type SimpleGraph (formerly Graph in the LightGraphs module).

Conversion between these two types (UndirectedGraph in this module and SimpleGraph in the Graphs module) is supported; see the file graph_converter.jl in the extras directory.

This module defines three data types for working with graphs:

• The UndirectedGraph type represents undirected graphs without loops or multiple edges.
• The DirectedGraph type represents directed graphs in which there may be at most one directed edge (u,v) from a vertex u to a vertex v. There may also be a directed edge in the opposite direction, (v,u).
• The HyperGraph type representing hypergraphs in which edges may be any subset of the vertex set.

Additional functionality can be found in these modules:

• DrawSimpleGraphs for visualization.
• SimpleGraphAlgorithms for functions relying on [integer] linear programming.

In addition, we have:

• A nascent SimplePlanarGraphs module with extremely limited functionality.
• An older SimpleGraphRepresentations module that I am not currently maintaining.

Please see the Wiki for extensive information pertaining to the UndirectedGraph type.

The DirectedGraph type is not so well developed nor documented. See the source files in the src directory. Likewise, documentation and support for the HyperGraph type is limited.

The extras directory contains some additional functionality that may be useful. See the README file therein.

This software is part of a larger suite of tools for graph theory. More information can be found right after my explanation that this code is postcardware.

Thank you to JHU students Tara Abrishami and Laura Bao for contributions to this project.

This is a work in process with a lot of more features that can/should be added. If you're interested in contributing, please contact me. I'm especially interested in JHU undergraduates getting involved.

Ed Scheinerman (ers@jhu.edu)