tdULL is a submission for the PACE 2020 Treedepth Challenge by Ruben Brokkelkamp, Raymond van Venetië, Mees de Vries and Jan Westerdiep. It is a tool for computing the exact treedepth of a general graph.

This tool uses the C++ Boost library. For detailed installation instructions, see the Boost website.

This tool uses Gregory Popovitch's parallel hash map. After cloning the repository, before compiling, run git init submodule and then git submodule update to include this code.

To build the tool, navigate to the src directory and run make. This produces an executable called main, which can be used to compute treedepth: it expects a graph in the PACE Challenge input format from stdin, and will output an optimal treedepth decomposition of the graph in PACE Challenge output format to stdout. Additionally, it will output some general information to stderr.

The executable treedepth_test (also produced by make) applies tdULL to a selection of the public inputs of the PACE 2020 challenge. This test should take no more than a few minutes.

By the nature of the challenge, tdULL is the result of weeks of rapid experimentation. The resulting code is not especially legible or clean. It would not normally be published yet, if that were not a requirement for the PACE Challenge.