Abstract
We study finite convergence of the modified cyclic subgradient projections (MCSP) algorithm for the convex feasibility problem (CFP) in the Euclidean space. Expanding control sequences allow the indices of the sets of the CFP to re-appear and be used again by the algorithm within windows of iteration indices whose lengths are not constant but may increase without bound. Motivated by another development in finitely convergent sequential algorithms that has a significant real-world application in the field of radiation therapy treatment planning, we show that the MCSP algorithm retains its finite convergence when used with an expanding control that is repetitive and fulfills an additional condition.
Similar content being viewed by others
References
Bauschke, H.H., Borwein, J.M.: On projection algorithms for solving convex feasibility problems. SIAM Rev. 38, 367–426 (1996)
Byrne, C.: Iterative oblique projection onto convex sets and the split feasibility problem. Inverse Probl. 18, 441–453 (2002)
Cegielski, A.: Generalized relaxations of nonexpansive operators and convex feasibility problems. Contemp. Math. 513, 111–123 (2010)
Censor, Y.: Row-action methods for huge and sparse systems and their applications. SIAM Rev. 23, 444–466 (1981)
Censor, Y., Altschuler, M.D., Powlis, W.D.: On the use of Cimmino’s simultaneous projections method for computing a solution of the inverse problem in radiation therapy treatment planning. Inverse Probl. 4, 607–623 (1988)
Censor, Y., Lent, A.: Cyclic subgradient projections. Math. Program. 24, 233–235 (1982)
Censor, Y., Zenios, S.A.: Parallel Optimization: Theory, Algorithms, and Applications. Oxford University Press, New York (1997)
Chen, W., Herman, G.T.: Efficient controls for finitely convergent sequential algorithms. ACM Trans. Math. Softw. 37, Article No. 14 (2010)
Chen, W., Craft, D., Madden, T.M., Zhang, K., Kooy, H.M., Herman, G.T.: A fast optimization algorithm for multi-criteria intensity modulated proton therapy planning. Med. Phys. 37, 4938–4945 (2010)
Combettes, P.L.: The foundations of set-theoretic estimation. Proc. IEEE 81, 182–208 (1993)
Combettes, P.L.: The convex feasibility problem in image recovery. Adv. Imaging Electron Phys. 95, 155–270 (1996)
Combettes, P.L.: Hilbertian convex feasibility problem: Convergence of projection methods. Appl. Math. Optim. 35, 311–330 (1997)
De Pierro, A.R., Iusem, A.: A finitely convergent “row-action” method for the convex feasibility problem. Appl. Math. Optim. 17, 225–235 (1988)
Eremin, I.I.: The relaxation method for solving systems of inequalities with convex functions on the left-hand side. Sov. Math. Dokl., 6, 219–222 (1965)
Eremin, I.I.: On some iterative methods in convex programming. Ekonomika i Matematichesky Methody, 2, 870–886 (1966) (In Russian)
Goffin, J.L.: The relaxation method for solving systems of linear inequalities. Math. Oper. Res. 5, 388–414 (1980)
Herman, G.T.: Fundamentals of Computerized Tomography: Image Reconstruction from Projections, 2nd edn. Springer, Berlin (2009)
Herman, G.T.: A relaxation method for reconstructing objects from noisy x-rays. Math. Program. 8, 1–19 (1975)
Herman, G.T., Chen, W.: A fast algorithm for solving a linear feasibility problem with application to intensity-modulated radiation therapy. Linear Algebra Appl. 428, 1207–1217 (2008)
Jiang, M., Wang, G.: Convergence studies on iterative algorithms for image reconstruction. IEEE Trans. Med. Imaging 22, 569–579 (2003)
Kiwiel, K.C.: Block-iterative surrogate projection methods for convex feasibility problems. Linear Algebra Appl. 215, 225–259 (1995)
Marks, L.D., Sinkler, W., Landree, E.: A feasible set approach to the crystallographic phase problem. Acta Crystallogr. A55, 601–612 (1999)
Tseng, P.: On the convergence of the products of firmly nonexpansive mappings. SIAM J. Optim. 2, 425–434 (1992)
Tseng, P., Bertsekas, D.P.: Relaxation methods for problems with strictly convex separable costs and linear constraints. Math. Program. 38, 303–321 (1987)
Yamada, I.: Hybrid steepest descent method for variational inequality problem over the fixed point set of certain quasi-nonexpansive mappings. Numer. Funct. Anal. Optim. 25, 619–655 (2004)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Censor, Y., Chen, W. & Pajoohesh, H. Finite Convergence of a Subgradient Projections Method with Expanding Controls. Appl Math Optim 64, 273–285 (2011). https://doi.org/10.1007/s00245-011-9139-8
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00245-011-9139-8