François Pacaud
frapac.bsky.social
François Pacaud
@frapac.bsky.social
Mathematical optimization researcher @ Mines Paris
ExaModels is currently one of the fastest optimization modelers, and can evaluate (sparse) derivatives in parallel on various GPUs
June 30, 2025 at 4:26 PM
Nice initiative! Just a naive question regarding doi.org/10.1137/23M1.... You don't have to assume the strong Legendre-Clebsch condition to establish the convergence of your algorithm? What's the behavior of the interior-point method when the problem has singular arcs?
Interior Point Methods in Optimal Control Problems of Affine Systems: Convergence Results and Solving Algorithms | SIAM Journal on Control and Optimization
Abstract. This paper presents an interior point method for pure state and mixed-constraint optimal control problems for dynamics, mixed constraints, and cost function all affine in the control variabl...
doi.org
January 22, 2025 at 5:32 PM
Nw! We are using double precision, we need that to get an accurate convergence in IPM. It turns out the modern GPUs are much performant with double precision than the previous generations.
December 19, 2024 at 9:25 PM
In our experience we can achieve 1e-8 on medium instances, 1e-6 on large-scale ones. The condensed strategy induces an additional ill-conditioning that renders the method slightly less accurate than HSL solvers.
December 19, 2024 at 8:24 PM
Deadline is November 29th. The link to submit a contribution is: roadef2025.org/soumettre-un...
Soumettre un résumé - ROADEF 2025
roadef2025.org
November 27, 2024 at 10:32 AM
For CPU versus GPU, our main message is that you don't have to use an expensive GPU: I can get reasonable speed-up on the GPU I have on my laptop.
November 22, 2024 at 8:39 PM
Good question. We did some benchmarks a while ago, we found out it's non-trivial to estimate the energy usage on the CPU. As such we just made a benchmark comparing our new method (HyKKT) versus our previous one (Biegler). Solving one OPF problem amounts to at most 500J using the new method.
November 22, 2024 at 8:36 PM