Skip to main content

A primal–dual algorithm for risk minimization

Abstract

In this paper, we develop an algorithm to efficiently solve risk-averse optimization problems posed in reflexive Banach space. Such problems often arise in many practical applications as, e.g., optimization problems constrained by partial differential equations with uncertain inputs. Unfortunately, for many popular risk models including the coherent risk measures, the resulting risk-averse objective function is nonsmooth. This lack of differentiability complicates the numerical approximation of the objective function as well as the numerical solution of the optimization problem. To address these challenges, we propose a primal–dual algorithm for solving large-scale nonsmooth risk-averse optimization problems. This algorithm is motivated by the classical method of multipliers and by epigraphical regularization of risk measures. As a result, the algorithm solves a sequence of smooth optimization problems using derivative-based methods. We prove convergence of the algorithm even when the subproblems are solved inexactly and conclude with numerical examples demonstrating the efficiency of our method.

This is a preview of subscription content, access via your institution.

References

  1. Adams, R.A.: Sobolev Spaces. Academic Press, Orlando (1975)

    MATH  Google Scholar 

  2. Artzner, P., Delbaen, F., Eber, J.-M., Heath, D.: Coherent measures of risk. Math. Finance 9, 203–228 (1999)

    MathSciNet  MATH  Google Scholar 

  3. Attouch, H., Buttazzo, G., Michaille, G.: Variational Analysis in Sobolev and BV Spaces, vol. 6 of MPS/SIAM Series on Optimization. Society for Industrial and Applied Mathematics (SIAM), Philadelphia (2006)

    MATH  Google Scholar 

  4. Bauschke, H.H., Combettes, P.L.: Convex Analysis and Montone Operator Theory in Hilbert Space. CMS Books in Mathematics. Springer, New York (2011)

    Google Scholar 

  5. Ben-Tal, A., Teboulle, M.: An old-new concept of convex risk measures: the optimized certainty equivalent. Math. Finance 17, 449–476 (2007)

    MathSciNet  MATH  Google Scholar 

  6. Bertsekas, D.P.: Constrained Optimization and Lagrange Multiplier Methods. Academic Press, New York (1982)

    MATH  Google Scholar 

  7. Bertsekas, D.P.: Nonlinear Programming, Athena Scientific Optimization and Computation Series, 2nd edn. Athena Scientific, Belmont (1999)

    Google Scholar 

  8. Bonnans, J.F., Gilbert, J.C., Lemaréchal, C., Sagastizábal, C.A.: Numerical Optimization: Theoretical and Practical Aspects. Universitext, 2nd edn. Springer, Berlin (2006)

    MATH  Google Scholar 

  9. Bonnans, J.F., Shapiro, A.: Perturbation Analysis of Optimization Problems. Springer, Berlin (2000)

    MATH  Google Scholar 

  10. Cheridito, P., Li, T.: Dual characterization of properties of risk measures on Orlicz hearts. Math. Financ. Econ. 2, 29 (2008)

    MathSciNet  MATH  Google Scholar 

  11. Conn, A.R., Gould, N.I.M., Toint, P.L.: LANCELOT: A FORTRAN Package for Large Scale Nonlinear Optimization with Simple Bounds. Springer Series in Computational Mathematics, vol. 17. Springer, Berlin (1992)

    MATH  Google Scholar 

  12. Conn, A.R., Gould, N.I.M., Toint, P.L.: Trust-Region Methods. SIAM, Philadelphia (2000)

    MATH  Google Scholar 

  13. Eichhorn, A., Römisch, W.: Polyhedral risk measures in stochastic programming. SIAM J. Optim. 16, 69–95 (2005)

    MathSciNet  MATH  Google Scholar 

  14. Ermoliev, Y.: Stochastic quasigradient methods and their application to system optimization. Stochastics 9, 1–36 (1983)

    MathSciNet  MATH  Google Scholar 

  15. Guigues, V.: Multistep stochastic mirror descent for risk-averse convex stochastic programs based on extended polyhedral risk measures. Math. Program. 163, 169–212 (2017)

    MathSciNet  MATH  Google Scholar 

  16. Guigues, V., Römisch, W.: Sampling-based decomposition methods for multistage stochastic programs based on extended polyhedral risk measures. SIAM J. Optim. 22, 286–312 (2012)

    MathSciNet  MATH  Google Scholar 

  17. Hestenes, M.R.: Multiplier and gradient methods. J. Optim. Theory Appl. 4, 303–320 (1969)

    MathSciNet  MATH  Google Scholar 

  18. Hintermüller, M., Kunisch, K.: Path-following methods for a class of constrained minimization problems in function space. SIAM J. Optim. 17, 159–187 (2006)

    MathSciNet  MATH  Google Scholar 

  19. Kiwiel, K.C.: Methods of Descent for Nondifferentiable Optimization. Lecture Notes in Mathematics, vol. 1133. Springer, Berlin (1985)

    MATH  Google Scholar 

  20. Kouri, D.P.: A multilevel stochastic collocation algorithm for optimization of PDEs with uncertain coefficients. SIAM/ASA J. Uncertain. Quantif. 2, 55–81 (2014)

    MathSciNet  MATH  Google Scholar 

  21. Kouri, D.P., Heinkenschloss, M., Ridzal, D., van Bloemen Waanders, B.G.: A trust-region algorithm with adaptive stochastic collocation for PDE optimization under uncertainty. SIAM J. Sci. Comput. 35, A1847–A1879 (2013)

    MathSciNet  MATH  Google Scholar 

  22. Kouri, D.P., Heinkenschloss, M., Ridzal, D., van Bloemen Waanders, B.G.: Inexact objective function evaluations in a trust-region algorithm for PDE-constrained optimization under uncertainty. SIAM J. Sci. Comput. 36, A3011–A3029 (2014)

    MathSciNet  MATH  Google Scholar 

  23. Kouri, D.P., Shapiro, A.: Optimization of PDEs with Uncertain Inputs, pp. 41–81. Springer, New York (2018)

    MATH  Google Scholar 

  24. Kouri, D.P., Surowiec, T.M.: Risk-averse PDE-constrained optimization using the conditional value-at-risk. SIAM J. Optim. 26, 365–396 (2016)

    MathSciNet  MATH  Google Scholar 

  25. Kouri, D.P., Surowiec, T.M.: Existence and optimality conditions for risk-averse PDE-constrained optimization. SIAM/ASA J. Uncertain. Quantif. 6, 787–815 (2018)

    MathSciNet  MATH  Google Scholar 

  26. Kouri, D.P., Surowiec, T.M.: Epi-regularization of risk measures. Math. Oper. Res. 45(2), 774–795 (2020). https://doi.org/10.1287/moor.2019.1013

    Article  MathSciNet  MATH  Google Scholar 

  27. Kouri, D.P., von Winckel, G., Ridzal, D.: ROL: Rapid Optimization Library. https://trilinos.org/packages/rol (2017)

  28. Krokhmal, P.A.: Higher moment coherent risk measures. Quantit. Finance 7, 373–387 (2007)

    MathSciNet  MATH  Google Scholar 

  29. Lan, G., Nemirovski, A., Shapiro, A.: Validation analysis of mirror descent stochastic approximation method. Math. Program. 134, 425–458 (2012)

    MathSciNet  MATH  Google Scholar 

  30. Lin, C.-J., Moré, J.J.: Newton’s method for large bound-constrained optimization problems. SIAM J. Optim. 9, 1100–1127 (1999)

    MathSciNet  MATH  Google Scholar 

  31. Mäkelä, M.M., Neittaanmäki, P.: Nonsmooth Optimization : Analysis and Algorithms with Applications to Optimal Control. World Scientific Publishing Co., Inc, River Edge (1992)

    MATH  Google Scholar 

  32. Nedić, A., Ozdaglar, A.: Approximate primal solutions and rate analysis for dual subgradient methods. SIAM J. Optim. 19, 1757–1780 (2009)

    MathSciNet  MATH  Google Scholar 

  33. Nemirovski, A., Juditsky, A.B., Lan, G., Shapiro, A.: Robust stochastic approximation approach to stochastic programming. SIAM J. Optim. 19, 1574–1609 (2009)

    MathSciNet  MATH  Google Scholar 

  34. Nocedal, J., Wright, S.J.: Numerical Optimization, 2nd edn. Springer, Berlin (2006)

    MATH  Google Scholar 

  35. Polyak, B.T.: A New Method of Stochastic Approximation Type, Avtomat. i Telemekh., pp. 98–107 (1990)

  36. Polyak, B.T., Juditsky, A.B.: Acceleration of stochastic approximation by averaging. SIAM J. Control Optim. 30, 838–855 (1992)

    MathSciNet  MATH  Google Scholar 

  37. Powell, M.J.D.: A method for nonlinear constraints in minimization problems. In: Fletcher, R. (ed.) Optimization, pp. 283–298. Springer, Berlin (1969)

    Google Scholar 

  38. Rockafellar, R.T.: On the maximal monotonicity of subdifferential mappings. Pac. J. Math. 33, 209–216 (1970)

    MathSciNet  MATH  Google Scholar 

  39. Rockafellar, R.T.: Augmented Lagrangians and applications of the proximal point algorithm in convex programming. Math. Oper. Res. 1, 97–116 (1976)

    MathSciNet  MATH  Google Scholar 

  40. Rockafellar, R.T.: Monotone operators and the proximal point algorithm. SIAM J. Control Optim. 14, 877–898 (1976)

    MathSciNet  MATH  Google Scholar 

  41. Rockafellar, R.T.: Extended nonlinear programming. In: Pillo, G., Giannessi, F. (eds.) Nonlinear Optimization and Related Topics, pp. 381–399. Springer, Berlin (2000)

    MATH  Google Scholar 

  42. Rockafellar, R.T., Uryasev, S.: The fundamental risk quadrangle in risk management, optimization and statistical estimation. Surv. Oper. Res. Manag. Sci. 18, 33–53 (2013)

    MathSciNet  Google Scholar 

  43. Rockafellar, R.T., Wets, R.J.-B.: Scenarios and policy aggregation in optimization under uncertainty. Math. Oper. Res. 16, 119–147 (1991)

    MathSciNet  MATH  Google Scholar 

  44. Rockafellar, R.T., Wets, R.J.-B.: Variational Analysis. Springer, Berlin (1998)

    MATH  Google Scholar 

  45. Sakalauskas, L.L.: Nonlinear stochastic programming by Monte-Carlo estimators. Eur. J. Oper. Res. 137, 558–573 (2002)

    MathSciNet  MATH  Google Scholar 

  46. Schramm, H., Zowe, J.: A version of the bundle idea for minimizing a nonsmooth function: conceptual idea, convergence analysis, numerical results. SIAM J. Optim. 2, 121–152 (1992)

    MathSciNet  MATH  Google Scholar 

  47. Shapiro, A., Dentcheva, D., Ruszczynski, A.: Lectures on Stochastic Programming: Modeling and Theory. MOS-SIAM Series on Optimization, 2nd edn. Society for Industrial and Applied Mathematics, Philadelphia (2014)

    MATH  Google Scholar 

  48. Shor, N.Z.: Minimization Methods for Non-differentiable Functions. Springer, New York (1985)

    MATH  Google Scholar 

  49. Sion, M.: On general minimax theorems. Pac. J. Math. 8, 171–176 (1958)

    MathSciNet  MATH  Google Scholar 

  50. Ulbrich, M.: Semismooth Newton Methods for Variational Inequalities and Constrained Optimization Problems in Function Spaces. SIAM, Philadelphia (2011)

    MATH  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Drew P. Kouri.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

DPK’s research was sponsored by DARPA EQUiPS Grant SNL 014150709, AFOSR Grant F4FGA09135G001 and Sandia National Laboratories LDRD “Risk-Adaptive Experimental Design for High-Consequence Systems”. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under Contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government. TMS’s research was sponsored by the DFG Grant No. SU 963/1-1 “Generalized Nash Equilibrium Problems with Partial Differential Operators: Theory, Algorithms, and Risk Aversion”.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kouri, D.P., Surowiec, T.M. A primal–dual algorithm for risk minimization. Math. Program. 193, 337–363 (2022). https://doi.org/10.1007/s10107-020-01608-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10107-020-01608-9

Keywords

  • Risk-averse optimization
  • Coherent risk measures
  • Stochastic optimization
  • Method of multipliers

Mathematics Subject Classification

  • 49M29
  • 49M37
  • 65K10
  • 90C15
  • 93E20