Fractal Instances of the Traveling Salesman Problem
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
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The Euclidean Traveling Salesman Problem and a Space-Filling Curve ,
M. G. Norman and P. Moscato,
Chaos, Solitons and Fractals, Vol. 6, pages 389-397, 1995.
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Using L-Systems to generate arbitrarily large instances of the
Euclidean Traveling Salesman Problem with known optimal tours ,
A. Mariano, P. Moscato and M.G Norman,
``Anales del
XXVII Simposio Brasileiro de Pesquisa Operacional'',
Vitoria, Brazil, 6-8 Nov. 1995.
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An Analysis of the Performance of Traveling Salesman Heuristics on
Infinite-Size Fractal Instances in the Euclidean Plane.
P. Moscato and M.G. Norman, first version Oct. 1994,
to appear in ORSA Journal on Computing.
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Arbitrarily large planar ETSP instances with known optimal tours,
by A. Mariano, P. Moscato, and M.G. Norman, expanded version of the
paper presented at Vitoria, ES, Brazil, 1995. Paper accepted in
the journal ``Pesquisa Operacional''.
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.