About CATBox

The CATBox app is a companion to the textbook CATBox — An Interactive Course in Combinatorial Optimization by Winfried Hochstättler and Alexander Schliep published by Springer in 2010.

The animations of the algorithms implemented for the textbook are created with the open-source desktop software Gato by the same authors, which is also available as source and binaries from the website http://schliep.org/CATBox.

With Gato you can edit the graph instances the algorithms operate on and implement and animate your own algorithms. The animations can also be exported to HTML.


The graph animation toolbox (Gato) started its life 1997 at the Universität zu Köln as a cross-platform desktop application written in Python using Tkinter for its graphical user interface. Algorithms are also implemented in Python and semi-automatically animated. Development of Gato continued from 2002 until 2009 at the Max Planck Institute for Molecular Genetics in Berlin and, since 2009, at Rutgers, The State University of New Jersey.

A frequent feature request was backward execution, or to be able to jump back in the execution time-line. The solution was to record animation histories in Gato, combined with light-weight players for the animation histories. Additionally, this technical solution made both WebGato and the CATBox app feasible.

Developers of Web Gato

Scott Merkling is the main developer of the Gato app and WebGato online system; he was also the maintainer of Gato since 2012 and implemented the support of animation histories in Gato. Matt Mitsui implemented an earlier proof of concept of the WebGato online system. Alexander Schliep is the original author of Gato and has been directing the development of Gato, WebGato and the CATBox app ever since.


Scott Merkling and Matt Mitsui participated in the DIMACS REU program with support from NSF award CCF-1004956. The development of Gato, WebGato and the CATBox app was supported by Rutgers. The development of Gato was previously supported by the Universität zu Köln, the Max Planck Society and the Fernuniversität Hagen.