Publications

A. M. Kingston, A. Aminzadeh, L. Roberts, J. M. C. Brown, F. Salvemini, J. J. Bevitt, U. Garbe, D. M. Paganin (2025). Neutron beam shaping by ghost projection. Physical Review A.

M. S. Salehi, S. Mukherjee, L. Roberts, M. J. Ehrhardt (2025). An adaptively inexact first-order method for bilevel optimization with application to hyperparameter learning. SIAM J. Math. Data Science.

A. Aminzadeh, A. M. Kingston, L. Roberts, D. M. Paganin, T. C. Petersen, I. D. Svalbe (2025). High-resolution X-ray scanning with a diffuse Huffman-patterned probe to reduce radiation damage. J. Synchrotron Radiation.

Preprint Journal

L. Roberts (2025). Model Construction for Convex-Constrained Derivative-Free Optimization. SIAM J. Optim.

Preprint Journal

M. S. Salehi, S. Mukherjee, L. Roberts, M. J. Ehrhardt (2025). Bilevel Learning with Inexact Stochastic Gradients. SSVM 2025.

Preprint Journal

M. N. Dao, H. M. Phan, L. Roberts (2025). Projected proximal gradient trust-region algorithm for nonsmooth optimization.

C. Cartis, L. Roberts (2024). Randomized Subspace Derivative-Free Optimization with Quadratic Models and Second-Order Convergence.

W. Hare, L. Roberts, C. W. Royer (2024). Expected decrease for derivative-free algorithms using random subspaces. Mathematics of Computation.

Preprint Journal

Y. Liu, K. H. Lam, L. Roberts (2024). Black-box Optimization Algorithms for Regularized Least-squares Problems.

A. Berahas, L. Roberts, F. Roosta (2024). Non-Uniform Smoothness for Gradient Descent. Trans. on Machine Learning Research.

M. J. Ehrhardt, L. Roberts (2023). Analyzing Inexact Hypergradients for Bilevel Learning. IMA J. Appl. Math..

Preprint Journal

L. Roberts, C. W. Royer (2023). Direct search based on probabilistic descent in reduced spaces. SIAM J. Optim..

Preprint Code Journal

A. Aminzadeh, L. Roberts, B. Young, C. Chiang, I. D. Svalbe, D. M. Paganin, A. M. Kingston (2023). Mask design, fabrication, and experimental ghost imaging applications for patterned X-ray illumination. Optics Express.

A. M. Kingston, A. Aminzadeh, L. Roberts, D. Pelliccia, I. D. Svalbe, D. M. Paganin (2023). Optimizing illumination patterns for classical ghost imaging. Physical Review A.

Preprint Journal

M. J. McGuinness, B. J. Cox, B. Kalyanaraman, K. B. Kiradjiev, R. Gonzalez-Farina, C. Z. W. Hassell Sweatman, L. Roberts, D. I. Pontin, E. J. Bissaker, S. K. Irvine, D. R. Jenkins, I. J. Taggart (2023). Furnace Vestibule Heat Transport Models. ANZIAM J..

Y. Zhen, T. X. Ho, L. Roberts, L. R. Schimleck, A. Sinha (2022). On the selection of the weighting parameter value in optimizing Eucalyptus globulus pulp yield models based on NIR spectra. Wood Science and Technology.

J. Fowkes, L. Roberts, A. Bűrmen (2022). PyCUTEst: an open source Python package of optimization test problems. Journal of Open Source Software.

M. Hough, L. Roberts (2022). Model-Based Derivative-Free Methods for Convex-Constrained Optimization. SIAM J. Optim..

Preprint Code Journal

L. Roberts, E. Smyth (2022). A Simplified Convergence Theory for Byzantine Resilient Stochastic Gradient Descent. EURO J. Comp. Optim..

Preprint Journal

C. Cartis, L. Roberts (2022). Scalable Subspace Methods for Derivative-Free Nonlinear Least-Squares Optimization. Math. Prog..

Preprint Code Journal

S. F. B. Tett, J. M. Gregory, N. Freychet, C. Cartis, M. J. Mineter, L. Roberts (2021). Does Model Calibration Reduce Uncertainty in Climate Projections?. J. Climate.

Code Dataset Journal

C. Cartis, L. Roberts, O. Sheridan-Methven (2021). Escaping local minima with local derivative-free methods: a numerical investigation. Optimization.

Preprint Code Journal

M. J. Ehrhardt, L. Roberts (2021). Inexact Derivative-Free Optimization for Bilevel Learning. J. Math. Imaging Vision.

Preprint Code Journal

M. J. Ehrhardt, L. Roberts (2020). Efficient Hyperparameter Tuning with Dynamic Accuracy Derivative-Free Optimization. OPT2020 (NeurIPS).

C. Cartis, T. Ferguson, L. Roberts (2020). Scalable Derivative-Free Optimization for Nonlinear Least-Squares Problems. ICML 2020.

C. Cartis, J. Fiala, B. Marteau, L. Roberts (2019). Improving the Flexibility and Robustness of Model-Based Derivative-Free Optimization Solvers. ACM Trans. Math. Soft.

Preprint Code Journal

L. Roberts (2019). Derivative-Free Algorithms for Nonlinear Optimisation Problems. DPhil Thesis.

C. Cartis, L. Roberts (2019). A Derivative-Free Gauss-Newton Method. Math. Prog. Comp.

Preprint Code Journal

M. Bazzi et al (2018). Capturing the Purpose of Websites. Alan Turing Institute Data Study Group.

A. Avdzhieva et al (2018). Cable Routing on Ships. 136th European Study Group with Industry.

L. Roberts, E. Nordgård-Hansen, Ø. Mikkelsen, S. A. Halvorsen, R. A. Van Gorder (2017). A heat and mass transfer study of carbon paste baking. Int. Commun. Heat Mass Transfer.

A. Champneys et al (2017). Optimising the Design of Polythene Hydroponics Beds. Agri-Food Study Group with Industry.

L. Roberts (2016). Derivative-Free Optimisation for Data Fitting. InFoMM CDT Report.

C. Sargent et al (2016). Flow dynamics in complex buildings (airports and rail stations). 116th European Study Group with Industry.