License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ESA.2017.60
URN: urn:nbn:de:0030-drops-78701
Go to the corresponding LIPIcs Volume Portal

Neuen, Daniel ; Schweitzer, Pascal

Benchmark Graphs for Practical Graph Isomorphism

LIPIcs-ESA-2017-60.pdf (0.7 MB)


The state-of-the-art solvers for the graph isomorphism problem can readily solve generic instances with tens of thousands of vertices. Indeed, experiments show that on inputs without particular combinatorial structure the algorithms scale almost linearly. In fact, it is non-trivial to create challenging instances for such solvers and the number of difficult benchmark graphs available is quite limited.

We describe a construction to efficiently generate small instances for the graph isomorphism problem that are difficult or even infeasible for said solvers.

Up to this point the only other available instances posing challenges for isomorphism solvers were certain incidence structures of combinatorial objects (such as projective planes, Hadamard matrices, Latin squares, etc.). Experiments show that starting from 1500 vertices our new instances are several orders of magnitude more difficult on comparable input sizes. More importantly, our method is generic and efficient in the sense that one can quickly create many isomorphism instances on a desired number of vertices. In contrast to this, said combinatorial objects are rare and difficult to generate and with the new construction it is possible to generate an abundance of instances of arbitrary size.

Our construction hinges on the multipedes of Gurevich and Shelah and the Cai-F├╝rer-Immerman gadgets that realize a certain abelian automorphism group and have repeatedly played a role in the context of graph isomorphism. Exploring limits, we also explain that there are group theoretic obstructions to generalizing the construction with non-abelian gadgets.

BibTeX - Entry

  author =	{Daniel Neuen and Pascal Schweitzer},
  title =	{{Benchmark Graphs for Practical Graph Isomorphism}},
  booktitle =	{25th Annual European Symposium on Algorithms (ESA 2017)},
  pages =	{60:1--60:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-049-1},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{87},
  editor =	{Kirk Pruhs and Christian Sohler},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-78701},
  doi =		{10.4230/LIPIcs.ESA.2017.60},
  annote =	{Keywords: graph isomorphism, benchmark instances, practical solvers}

Keywords: graph isomorphism, benchmark instances, practical solvers
Collection: 25th Annual European Symposium on Algorithms (ESA 2017)
Issue Date: 2017
Date of publication: 01.09.2017

DROPS-Home | Fulltext Search | Imprint | Privacy Published by LZI