Abstract
In this paper, elliptic optimal control problems involving the \(L^1\)-control cost (\(L^1\)-EOCP) is considered. To numerically discretize \(L^1\)-EOCP, the standard piecewise linear finite element is employed. However, different from the finite dimensional \(l^1\)-regularization optimization, the resulting discrete \(L^1\)-norm does not have a decoupled form. A common approach to overcome this difficulty is employing a nodal quadrature formula to approximately discretize the \(L^1\)-norm. It is clear that this technique will incur an additional error. To avoid the additional error, solving \(L^1\)-EOCP via its dual, which can be reformulated as a multi-block unconstrained convex composite minimization problem, is considered. Motivated by the success of the accelerated block coordinate descent (ABCD) method for solving large scale convex minimization problems in finite dimensional space, we consider extending this method to \(L^1\)-EOCP. Hence, an efficient inexact ABCD method is introduced for solving \(L^1\)-EOCP. The design of this method combines an inexact 2-block majorized ABCD and the recent advances in the inexact symmetric Gauss–Seidel (sGS) technique for solving a multi-block convex composite quadratic programming whose objective contains a nonsmooth term involving only the first block. The proposed algorithm (called sGS-imABCD) is illustrated at two numerical examples. Numerical results not only confirm the finite element error estimates, but also show that our proposed algorithm is more efficient than (a) the ihADMM (inexact heterogeneous alternating direction method of multipliers), (b) the accelerated proximal gradient method.
Similar content being viewed by others
Notes
For more details about the iFEM software package, we refer to the website http://www.math.uci.edu/~chenlong/programming.html
References
Stadler, G.: Elliptic optimal control problems with \(L^1\)-control cost and applications for the placement of control devices. Comput. Optim. Appl. 44, 159–181 (2009)
Hinze, M.: A variational discretization concept in control constrained optimization: the linear-quadratic case. Comput. Optim. Appl. 30, 45–61 (2005)
Falk, R.S.: Approximation of a class of optimal control problems with order of convergence estimates. J. Math. Anal. Appl. 44, 28–47 (1973)
Geveci, T.: On the approximation of the solution of an optimal control problem problem governed by an elliptic equation. RAIRO-Analyse numérique 13, 313–328 (1979)
Rösch, A.: Error estimates for linear-quadratic control problems with control constraints. Optim. Methods Softw. 21, 121–134 (2006)
Casas, E., Tröltzsch, F.: Error estimates for linear-quadratic elliptic control problems. In: IFIP TC7/WG7.2 International working conference on analysis and optimization of differential systems, September 10–14, 2002, Constanta, Romania, pp. 89–100 (2002)
Meyer, C., Rösch, A.: Superconvergence properties of optimal control problems. SIAM J. Control Optim. 43, 970–985 (2004)
Casas, E.: Using piecewise linear functions in the numerical approximation of semilinear elliptic control problems. Adv. Comput. Math. 26, 137–153 (2007)
Wachsmuth, G., Wachsmuth, D.: Convergence and regularisation results for optimal control problems with sparsity functional. ESAIM Control Optim. Calc. Var. 17, 858–886 (2011)
Casas, E., Herzog, R., Wachsmuth, G.: Approximation of sparse controls in semilinear equations by piecewise linear functions. Numer. Math. 122, 645–669 (2012)
Casas, E., Herzog, R., Wachsmuth, G.: Optimality conditions and error analysis of semilinear elliptic control problems with \(L^1\) cost functional. SIAM J. Optim. 22, 795–820 (2012)
Clason, C., Kunisch, K.: A duality-based approach to elliptic control problems in non-reflexive Banach spaces. ESAIM Control Optim. Calc. Var. 17, 243–266 (2011)
Casas, E., Clason, C., Kunisch, K.: Approximation of elliptic control problems in measure spaces with sparse solutions. SIAM J. Control Optim. 50, 1735–1752 (2012)
Collis, S.S., Heinkenschloss M.: Analysis of the streamline upwind/Petrov Galerkin method applied to the solution of optimal control problems. CAAM TR02-01 (2002)
Bergounioux, M., Ito, K., Kunisch, K.: Primal–dual strategy for constrained optimal control problems. SIAM J. Control Optim. 37, 1176–1194 (1999)
Ulbrich, M.: Nonsmooth Newton-like methods for variational inequalities and constrained optimization problems in function spaces. Habilitation thesis, Fakultät für Mathematik, Technische Universität München (2002)
Ulbrich, M.: Semismooth Newton methods for operator equations in function spaces. SIAM J. Optim. 13, 805–842 (2003)
Hinze, M., Pinnau, R., Ulbrich, M., Ulbrich, S.: Optimization with PDE Constraints, vol. 23. Springer, Berlin (2008)
Hintermüller, M., Ulbrich, M.: A mesh-independence result for semismooth Newton methods. Math. Program. 101, 151–184 (2004)
Porcelli, M., Simoncini, V., Stoll, M.: Preconditioning PDE-constrained optimization with \(L^1\)-sparsity and control constraints. Comput. Math. Appl. 74, 1059–1075 (2017)
Herzog, R., Ekkehard, S.: Preconditioned conjugate gradient method for optimal control problems with control and state constraints. SIAM J. Matrix Anal. Appl. 31, 2291–2317 (2010)
Blumensath, T., Davies, M.E.: Iterative thresholding for sparse approximations. J. Fourier Anal. Appl. 14, 629–654 (2008)
Jiang, K., Sun, D.F., Toh, K.C.: An inexact accelerated proximal gradient method for large scale linearly constrained convex SDP. SIAM J. Optim. 22, 1042–1064 (2012)
Beck, A., Teboulle, M.: A fast iterative shrinkage-thresholding algorithm for linear inverse problems. SIAM J. Imaging Sci. 2, 183–202 (2009)
Toh, K.C., Yun, S.: An accelerated proximal gradient algorithm for nuclear norm regularized linear least squares problems. Pac. J. Optim. 6, 615–640 (2010)
Fazel, M., Pong, T.K., Sun, D.F., Tseng, P.: Hankel matrix rank minimization with applications to system identification and realization. SIAM J. Matrix Anal. Appl. 34, 946–977 (2013)
Chen, L. Sun, D.F., Toh, K.C.: An efficient inexact symmetric Gauss–Seidel based majorized ADMM for high-dimensional convex composite conic programming. Math. Program. 161, 237–270 (2017)
Li, X.D., Sun, D.F., Toh, K.C.: A Schur complement based semi-proximal ADMM for convex quadratic conic programming and extensions. Math. Program. 155, 333–373 (2016)
Li, X.D., Sun, D.F., Toh, K.C.: QSDPNAL: a two-phase Newton-CG proximal augmented Lagrangian method for convex quadratic semidefinite programming problems. arXiv:1512.08872 (2015)
Song, X.L., Yu, B., Wang, Y.Y., Zhang, X.Z.: An inexact heterogeneous ADMM algorithm for elliptic optimal control problems with \(L^1\)-control cost. arXiv:1709.01067 (2017)
Schindele, A., Borzì, A.: Proximal methods for elliptic optimal control problems with sparsity cost functional. Appl. Math. 7, 967–992 (2016)
Chambolle, A., Dossa, C.: A remark on accelerated block coordinate descent for computing the proximity operators of a sum of convex functions. https://hal.archives-ouvertes.fr/hal-01099182 (2015)
Sun, D.F., Toh, K.C., Yang, L.Q.: An efficient inexact ABCD method for least squares semidefinite programming. SIAM J. Optim. 26, 1072–1100 (2016)
Cui, Y.: Large scale composite optimization problems with coupled objective functions: theory, algorithms and applications. Ph.D. thesis, National University of Singapore (2016)
Kinderlehrer, D., Stampacchia, G.: An Introduction to Variational Inequalities and their Applications, vol. 31. SIAM, Philadelphia (1980)
Hiriart-Urruty, J.-B., Strodiot, J.-J., Nguyen, V.H.: Generalized Hessian matrix and second-order optimality conditions for problems with \(C^ {1,1}\) data. Appl. Math. Optim. 11, 43–56 (1984)
Wathen, A.J.: Realistic eigenvalue bounds for the Galerkin mass matrix. IMA J. Numer. Anal. 7, 449–457 (1987)
Li, X.D.: A two-phase augented Lagrangian method for convex composite quadratic programming. Ph.D. thesis, National University of Singapore (2015)
Rees, T., Dollar, H.S., Wathen, A.J.: Optimal solvers for PDE-constrained optimization. SIAM J. Sci. Comput. 32, 271–298 (2010)
Rees, T., Wathen, A.J.: Chebyshev semi-iteration in preconditioning for problems including the mass matrix. Electron. Trans. Numer Anal. 34, 125–135 (2009)
Bai, Z.Z., Benzi, M., Chen, F., Wang, Z.Q.: Preconditioned MHSS iteration methods for a class of block two-by-two linear systems with applications to distributed control problems. IMA J. Numer. Anal. 33, 343–369 (2013)
Elman, H.C., Silvester, D.J., Wathen, A.J.: Finite Elements and Fast Iterative Solvers: With Applications in Incompressible Fluid Dynamics. Oxford University Press, Oxford (2014)
Song, X., Chen, B., Yu, B.: Error estimates for sparse optimal control problems by piecewise linear finite element approximation. arXiv:1709.09539 (2017)
Chen, L.: iFEM: an integrated finite element methods package in MATLAB. Technical report, Department of Mathematics, University of California at Irvine, Irvine (2008)
Acknowledgements
The authors would like to thank Prof. Defeng Sun and Prof. Kim-Chuan Toh at National University of Singapore for their valuable suggestions that led to improvement in this paper and also would like to thank Prof. Long Chen for the FEM package iFEM [44] in Matlab.
Author information
Authors and Affiliations
Corresponding author
Additional information
The research of this author was supported by China Scholarship Council while visiting the National University of Singapore and the National Natural Science Foundation of China (Grant Nos. 91230103, 11571061, 11401075).
Rights and permissions
About this article
Cite this article
Song, X., Chen, B. & Yu, B. An efficient duality-based approach for PDE-constrained sparse optimization. Comput Optim Appl 69, 461–500 (2018). https://doi.org/10.1007/s10589-017-9951-4
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10589-017-9951-4