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PACE Solver Description: Tweed-Plus: A Subtree-Improving Heuristic Solver for Treedepth

Author James Trimble

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James Trimble
  • School of Computing Science, University of Glasgow, Scotland, UK


Many thanks to the program committee of PACE 2020 and the team for an enjoyable contest.

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James Trimble. PACE Solver Description: Tweed-Plus: A Subtree-Improving Heuristic Solver for Treedepth. In 15th International Symposium on Parameterized and Exact Computation (IPEC 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 180, pp. 35:1-35:4, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


This paper introduces Tweed-Plus, a heuristic solver for the treedepth problem. The solver uses two well-known algorithms to create an initial elimination tree: nested dissection (making use of the Metis library) and the minimum-degree heuristic. After creating an elimination tree of the entire input graph, the solver continues to apply nested dissection and the minimum-degree heuristic to parts of the graph with the aim of replacing subtrees of the elimination tree with alternatives of lower depth.

Subject Classification

ACM Subject Classification
  • Theory of computation → Graph algorithms analysis
  • Theory of computation → Algorithm design techniques
  • Treedepth
  • Elimination Tree
  • Heuristics


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