Gato - the Graph Animation Toolbox - is a software which visualizes algorithms on graphs. Graphs are mathematical objects consisting of vertices and edges connecting pairs of vertices: think of cities as vertices and interstates as edges connecting two cities. Algorithms might find a shortest path - the fastest route - or a minimal spanning tree or solve one of other interesting problems on graphs: maximal-flow, weighted and non-weighted matching and min-cost flow. Visualisation means linking cause - the statements of an algorithm - immediately to an effect - changes to the graph the algorithm has as its input - by terms of blinking, changing colors and other visual effects.

Gato is copyright (c) 1998-2011 Alexander Schliep, and Winfried Hochstättler and copyright (c) 1998-2001 ZAIK/ZPR, an institute at the Unversität zu Köln. Gato is freely available under the LGPL and runs on all plattforms Python and Tcl/Tk run on, which includes at least Unix, Linux, MacOS X and Windows 98 onwards.

Gato is used in CATBox (the Combinatorial Algorithm Toolbox - an interactive course on discrete mathematics) available from Springer Verlag and has been used for courses on algorithms - both in the Computer Science and the Mathematics department - taught at the University of Cologne, the Technical University Cottbus and Free University Berlin. You find binary releases at

The development of Gato is hosted on Sourceforge. Thanks for the support.