Fractal Instances of the Traveling Salesman Problem

This page contains resources on the evolving field of the generation of instances of combinatorial optimization problems with known optimal solution.

There are currently four available papers on this subject.

Papers

Using L-Systems to generate TSP Instances

A software that generate TSP instances in TSPLIB format is available here . Please refer to the following paper

More information about the Sierpinski constructions can be obtained from the page called Sierpinski Gasket , by Paul Bourke.

Tutorials on L-Systems

Software for L-Systems

  • L-Systems Software , a page maintained by Mark S. Hammel.
  • LGrammar - A Graphics Tool for Lindenmayer Systems , LGrammar implements a two-dimensional and a three-dimensional graphics tool for evaluating Lindenmayer grammars. The LGrammar software runs on almost all Unix systems under X window. Source code and a number of sample flowers and other recursice structures are available via ftp.
  • A Lindenmayer-Systems Implementation , by Brian Horling, My senior thesis (research project) is to implement a Lindenmayer-System modler for for the Macintosh. This program would include several features over what our current commercial package can perform, such as virtual synchronous branch growth, context-sensitive branch termination and stochastic model stability.
  • L-System Plant Geometry Generator , by Hung-Wen Chen.
  • Building Trees using L-Systems , by Phil Drinkwater.
  • Laurens Lapre's Lparser Link, by Laurens Lapre. The Lparser software is free and can be freely distributed. The source is not available for the public domain.

    Other relevant papers

  • The Dimension of the Brownian Frontier is Greater than 1, by C. Bishop, P. Jones, R. Pemantle, and Y. Peres, Institute for Mathematical Sciences, Stony Brook, Preprint IMS95-9, (1995). Thanks to Melvyn Laffitte, who has pointed out this reference.
  • Rectifiable sets and the Travelling Salesman Problem, P.W. Jones, Invent. Math. 102, 1-15.
  • Characterizations of rectifiable sets in R^n, K. Okikiolu, J. London Math. Soc. 46, 336-348.
  • Worst-case bounds for subadditive geometric graphs, M. Bern and D. Eppstein, 9th ACM Symp. Comp. Geom., San Diego (1993) 183-188.
  • On the Spacefilling Curve Heuristic for the Euclidean Traveling Salesman Problem , by D. Bertsimas and M. Grigni.
  • Beta-Skeletons have Unbounded Dilation, ICS-TR-96-15, May 1996. David Eppstein shows, using a fractal construction, that for any beta>0, the beta-skeleton of a point set can have arbitrarily large dilation. Beta-skeletons are geometric graphs used in empirical network analysis and minimum length triangulations.
  • Asymptotic Length Bounds and Fractal Dimension, by Lynn Robitaille and Meera Sitharam, Unpublished Kent State University Technical Report, August 1996.

    Craig Tovey has contributed with some other references on test case instance generators

  • Analysis of a Random Cut Test Instance Generator for the TSP, by Ron Rardin, Craig Tovey, and Martha Pilcher in P. Pardalos, ed., Complexity in Numerical Optimization, pp. 387-405, World Scientific Publishing, 1993.
  • Partial Polyhedral Description and Generation of Discrete Opitmizaiton Problems with Known Optima, by M. Pilcher and R. Rardin, Naval Research Logistics, 199? (sorry, we don't have the year).
  • On the complexity of Test Case Generation for NP-hard Problems, by L. Sanchis, Information Processing Letters 36, pp. 135--140, 1990.

    Miscellaneous links

  • Our curve MNPeano has some similarity with ``kolam'' patterns. Please see the beautiful page on Symmetry in Threshold Design in South India , by Manorama Talaiver.
  • Real Time Transformation of Musical Material with Fractal Algorithms , by Gary Lee Nelson.
  • Understanding Self-Similar Fractals , a book by Roger T. Stevens.
  • Computer Representation and Rendering of Trees , by Paul Bourke.
  • ArtByMath Fractals, by René Ertzinger.


    Pablo Moscato
    Densis - FEEC - UNICAMP
    Universidade Estadual de Campinas
    Caixa Postal 6101
    13081-970 Campinas - SP
    BRAZIL
    email: moscato@cacr.caltech.edu
    email: moscato@densis.fee.unicamp.br

    Click here for my complete address and contact information.

    Page created Feb. 29, 1996
    Last update Feb. 8, 1998

    Counter set to zero at Jun. 24, 1998, A.C.