# Publications

Published papers

- (with D. Ek),
*A structured modified Newton approach for solving systems of nonlinear equations arising in interior-point methods for quadratic programming*, Computational Optimization and Applications 86 (2023), 1–48. - (with I. Bengtsson and A. Fredriksson),
*Implications of using the clinical target distribution as voxel-weights in radiation therapy optimization*, Physics in Medicine & Biology 68 (2023), 095005. - (with D. Ek),
*Exact linesearch limited-memory quasi-Newton methods for minimizing a quadratic function,*Computational Optimization and Applications - (with D. Ek),
*Approximate solution of system of linear equations arising in interior-point methods for bound-constrained optimization*, Computational Optimization and Applications 79 (2021), 155–191. - (with F. Wang),
*On the existence of a short pivoting sequence for a linear program*. Operations Research Letters 48 (2020), 697-702. - (with E. Hagrot, H. Æ. Oddsdóttir, M. Mäkinen and V. Chotteau),
*Novel column generation-based optimization approach for poly-pathway kinetic model applied to CHO cell culture*. Metabolic Engineering Communications 8 (2019), e00083. -
(with M. Böck and K. Eriksson),
*On the interplay between robustness and dynamic planning for adaptive radiation therapy.*Biomedical Physics & Engineering Express 5*.* - (with L. Engberg and K. Eriksson),
*Increased accuracy of planning tools for optimization of dynamic multileaf collimator delivery of radiotherapy through reformulated objective functions*. Physics in Medicine & Biology 63 (2018) 125012. (Also available as arXiv:1802.00619 [math.OC]) - (with T. Odland),
*On exact linesearch quasi-Newton methods for minimizing a quadratic function*. Computational Optimization and Applications 69 (2018), 225-241. (Also available as arXiv:1503.01892 [math.OC]) - (with M. Böck, K. Eriksson and B. Hårdemark),
*Towards robust adaptive radiation therapy strategies*. Medical Physics 44 (2017), 2054-2065. (Also available as arXiv:1611.01399 [math.OC]) - (with L. Engberg, K. Eriksson and B. Hårdemark),
*Explicit optimization of plan quality measures in intensity-modulated radiation therapy treatment planning*. Medical Physics 44 (2017) 2045-2053. (Also available as arXiv:1607.01148 [physics.med-ph]) - (with P. E. Gill and E. Wong),
*Primal and dual active-set methods for convex quadratic programming*, Mathematical Programming 159 (2016), 469-508. (Also available as arXiv:1503.08349 [math.OC]) - (with H. Æ. Oddsdóttir, E. Hagrot and V. Chotteau),
*Robustness analysis of elementary flux modes generated by column generation*, Mathematical Biosciences 273 (2016), 45-56. (Also available as arXiv:1503.03459 [math.OC]) - (with H. Æ. Oddsdóttir, E. Hagrot and V. Chotteau),
*On dynamically generating relevant elementary flux modes in a metabolic network using optimization*. Journal of Mathematical Biology 71 (2015), 903-920. (Also available as arXiv:1410.2680 [math.OC]) - (with A. Fredriksson and B. Hårdemark), Maximizing the probability of satisfying the clinical goals in radiation therapy treatment planning under setup uncertainty, Medical Physics 42 (2015), 3992–3999.
- (with T. Odland),
*On the connection between the conjugate gradient method and quasi-Newton methods on quadratic problems*. Computational Optimization and Applications 60 (2015), 377-392 . (Also available as arXiv:1407.1268 [math.OC]) - (with F. Carlsson),
*On column generation approaches for approximate solutions of quadratic programs in intensity-modulated radiation therapy*. Annals of Operations Research 223 (2014), 471-481. - (with R. Bokrantz),
*An algorithm for approximating convex Pareto surfaces based on dual techniques*. INFORMS Journal on Computing 25 (2013), 377-393. - (with A. Fredriksson and B. Hårdemark),
*Minimax optimization for handling range and setup uncertainties in proton therapy*. Medical Physics 38 (2011), 1672-1684. - (with P. E. Gill and J. D. Griffin),
*Iterative solution of augmented systems arising in interior methods*. SIAM Journal on Optimization 18 (2007), 666-690. - (with F. Carlsson, H. Rehbinder and K. Eriksson),
*Using eigenstructure of the Hessian to reduce the dimension of the intensity modulated radiation therapy optimization problem*. Annals of Operations Research 148 (2006), 81-94. *On warm starts for interior methods*. In IFIP International Federation for Information Processing, volume 199, System Modeling and Optimization, eds. F. Ceragioli, A. Dontchev, H. Furuta, K. Marti, and L. Pandolfi, pp. 51-66. Springer, Boston, 2006.- (with F. Carlsson),
*Iterative regularization in intensity-modulated radiation therapy optimization*. Medical Physics 33 (2006), 225-234. - (with P. E. Gill and M. H. Wright),
*Interior methods for nonlinear optimization.*SIAM Review 44 (2002), 525-597. *Inertia-controlling factorizations for optimization algorithms.*Applied Numerical Mathematics 43 (2002), 91-107.- (with M. Prytz),
*Dimensioning multicast-enabled communications networks.*Networks 39 (2002), 216-231. - (with G. Sporre),
*On weighted linear least-squares problems related to interior methods for convex quadratic programming.*SIAM Journal on Matrix Analysis and Applications 23 (2001), 42-56. *Optimality conditions for nonconvex semidefinite programming.*Mathematical Programming 88 (2000), 105-128.- (with P. E. Gill),
*Primal-dual interior methods for nonconvex nonlinear programming.*SIAM Journal on Optimization 8 (1998), 1132-1152. - (with W. Murray),
*Newton methods for large-scale linear inequality-constrained minimization.*SIAM Journal on Optimization 7 (1997), 162-176. *On linear least-squares problems with diagonally dominant weight matrices.*SIAM Journal on Matrix Analysis and Applications 17 (1996), 763-788.- (with P. E. Gill and J. R. Shinnerl),
*Stability of symmetric ill-conditioned systems arising in interior methods for constrained optimization.*SIAM Journal on Matrix Analysis and Applications 17 (1996), 187-211. - (with P. E. Gill and W. Murray),
*Computing modified Newton directions using a partial Cholesky factorization.*SIAM Journal on Scientific Computing 16 (1995), 139-150. - (with U. Ringertz),
*On the use of a modified Newton method for nonlinear finite element analysis.*Computer Methods in Applied Mechanics and Engineering 110 (1993), 275-283. - (with W. Murray),
*Newton methods for large-scale linear equality-constrained minimization.*SIAM Journal on Matrix Analysis and Applications 14 (1993), 560-587. - (with P. E. Gill and W. Murray),
*On the identification of local minimizers in inertia-controlling methods for quadratic programming.*SIAM Journal on Matrix Analysis and Applications 12 (1991), 730-746.

Technical reports and preprints

- (with S. Peng, G. Canessa and D. Ek),
*Quasi-Newton methods for minimizing a quadratic function subject to uncertainty,*arXiv:2109.00072 [math.OC], 2021. - (with D. Ek),
*An optimization derivation of the method of conjugate gradients,*arXiv:2011.02337 [math.OC], 2020. - (with L. Engberg),
*On tradeoffs between treatment time and plan quality of volumetric-modulated arc therapy with sliding-window delivery*, arXiv:1810.08610 [physics.med-ph], 2018. - (with T. Odland),
*On solving symmetric systems of linear equations in an unnormalized Krylov subspace framework*, arXiv:1409.4937 [math.OC], 2014. - (with M. H. Wright),
*An elementary proof of linear programming optimality conditions without using Farkas' lemma*, arXiv:1407.1240 [math.OC], 2014. - (with A. Fredriksson and B. Hårdemark)
*Optimizing the scenario positions for robust radiation therapy treatment planning*, Report TRITA-MAT-2012-OS5, Department of Mathematics, KTH Royal Institute of Technology, 2012. - (with R. Bokrantz),
*A dual algorithm for approximating Pareto sets in convex multi-criteria optimization*. Report TRITA-MAT-2011-OS3, Department of Mathematics, Royal Institute of Technology, 2011. - (with M. Fallgren and G. Fodor),
*An optimization approach to joint cell, channel and power allocation in multicell networks*. Report TRITA-MAT-2011-OS2, Department of Mathematics, Royal Institute of Technology, 2011. *A sufficiently exact inexact Newton step based on reusing matrix information*. Report TRITA-MAT-2009-OS7, Department of Mathematics, Royal Institute of Technology, 2009.*An elementary proof of optimality conditions for linear programming*. Report TRITA-MAT-2008-OS6, Department of Mathematics, Royal Institute of Technology, 2008.- (with F. Carlsson),
*A conjugate-gradient based approach for approximate solutions of quadratic programs*. Report TRITA-MAT-2008-OS2, Department of Mathematics, Royal Institute of Technology, 2008. *On the behavior of the conjugate-gradient method on ill-conditioned problems*. Report TRITA-MAT-2006-OS1, Department of Mathematics, Royal Institute of Technology, 2006.- (with G. Sporre),
*Characterization of the limit point of the central path in semidefinite programming.*Report TRITA-MAT-2002-OS12, Department of Mathematics, Royal Institute of Technology, 2002. - (with G. Sporre),
*Relations between divergence of multipliers and convergence to infeasible points in primal-dual interior methods for nonconvex nonlinear programming.*Report TRITA-MAT-2002-OS7, Department of Mathematics, Royal Institute of Technology, 2002. - (with M. Prytz),
*Dimensioning of a multicast network that uses shortest path routing distibution trees.*Report TRITA-MAT-2002-OS1, Department of Mathematics, Royal Institute of Technology, 2002. *A note on maximum-smoothness approximation of forward interest rate.*Report TRITA-MAT-1998-OS3, Department of Mathematics, Royal Institute of Technology, 1998.*Newton methods for nonconvex optimization.*Report TRITA-MAT-1990-10, Department of Mathematics, Royal Institute of Technology, 1990. (Doctoral thesis).- (with P. E. Gill and W. Murray),
*A modified Newton method for unconstrained minimization.*Report SOL 89-12, Department of Operations Research, Stanford University, 1989.