Abstract.
We prove convergence of two algorithms approximating invariant measures to iterated function systems numerically. We consider IFSs with finitely many continuous and injective non-overlapping maps on the unit interval. The first algorithm is a version of the Ulam algorithm for IFSs introduced by Strichartz et al. [16]. We obtain convergence in the supremum metric for distribution functions of the approximating eigen-measures to a unique invariant measure for the IFS. We have to make some modifications of the usual way of treating the Ulam algorithm due to a problem concerning approximate eigenvalues, which is part of our more general situation with weights not necessarily being related to the maps of the IFS. The second algorithm is a new recursive algorithm which is an analogue of forward step algorithms in the approximation theory of ODEs. It produces a sequence of approximating measures that converges to a unique invariant measure with geometric rate in the supremum metric. The main advantage of the recursive algorithm is that it runs much faster on a computer (using Maple) than the Ulam algorithm.
Similar content being viewed by others
References
Baladi, V., Holschneider, M.: Approximation of nonessential spectrum of tranfer operators. Nonlinearity 12, 525–538 (1999)
Baladi, V., Isola, S., Schmitt, B.: Transfer operators for piecewise affine approximations of interval maps. Ann. Inst. Henri Poincaré (phys. théor.) 62, 553–574 (1995)
Berger, N., Hoffman, C., Sidoravicius, V.: Nonuniqueness for specifications in ℓ2+∈. Preprint available on http://www.arxiv.org (PR/0312344 v2, 18 Dec 2003)
Bramson, M., Kalikow, S.: Nonuniqueness in g-functions. Israel J. Math. 84, 153–160 (1993)
Froyland, G., Aihara, K.: Rigorous numerical estimation of Lyapunov exponents and invariant measures of iterated function systems and random matrix products. Internat. J. Bifur. Chaos Appl. Sci. Engrg. 10 (1), 103–122 (2000)
Góra, P., Boyarsky, A.: Compactness of invariant densities for families of expanding, piecewise monotonic transformations. Can. J. Math. 41, 855–869 (1989)
Góra, P., Boyarsky, A.: Laws of Chaos Boston: Birkhäuser, 1997
Hennion, H.: Sur un théorème spectral et son application aux noyaux lipschitziens. Proc. Am. Math. Soc. 118, 627–634 (1993)
Hervé, L.: Étude d’operateurs quasi compacts positifs. Applications aux opérateurs de transfert. Ann. Inst. Henri Poinaré 30, 437–466 (1994)
Ionescu-Tulcea, C.T., Marinescu, G.: Théorie ergodique pour une classe d’opérations non complétement continues. Annals of Math. T. 50, 140–147 (1950)
Johansson, A., Öberg, A.: Square summability of variations of g-functions and uniqueness of g-measures. Math. Res. Lett. 10 (5–6), 587–601 (2003)
Keane, M., Murray, R., Young, L.-S.: Computing invariant measures for expanding circle maps. Nonlinearity 11, 27–46 (1998)
Keller, G., Liverani, C.: Stability of the Spectrum for Transfer Operators. Ann. Scuola Norm. Sup. Pisa C1. Sci. (4) 28 (1), 141–152 (1999)
Li, T.Y.: Finite approximation for the Perron–Frobenius operator. A solution to Ulam’s conjecture. J. of Approx. Theory 17, 177–186 (1976)
Öberg, A., Strichartz, R.S., Yingst, A.Q.: Level sets of harmonic functions on the Sierpinski gasket. Ark. Mat. 40 (2), 335–362 (2002)
Strichartz, R.S., Taylor, A., Zhang, T.: Densities of self-similar measures on the line. Experimental Mathematics 4, 101–128 (1995)
Viana, M.: Stochastic dynamics of deterministic systems. IMPA 1997. Available on Viana’s homepage
Author information
Authors and Affiliations
Corresponding author
Additional information
Mathematics Subject Classification (2000): 37A30, 37C30, 37M25, 47A58
Acknowledgement I would like to express my deep gratitude to Andreas Strömbergsson and to the anonymous referee. The referee had several very enlightening comments, which Andreas helped me to deal with. Section 4 is essentially due to Andreas and he also came up with the new Proposition 3 and helped me to improve Lemma 1. Thanks also to Svante Janson, Anders Johansson, Sten Kaijser, Robert Strichartz and Hans Wallin.
Rights and permissions
About this article
Cite this article
Öberg, A. Algorithms for approximation of invariant measures for IFS. manuscripta math. 116, 31–55 (2005). https://doi.org/10.1007/s00229-004-0515-4
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00229-004-0515-4