My name is Thibault Cimic, I’m a research engineer in applied mathematics specialized in linear algebra and PDE solvers. My job consists of turning mathematical ideas into efficient computational tools.

Current position

Since May 2025, I am on a 2-year contract at the CEA, jointly financed by two laboratories: L_Sim in Grenoble and the Maison de la Simulation in Saclay. This dual affiliation defines two complementary lines of work. On the L_Sim side, I am developing a new Kokkos backend for the psolver module of the BigDFT suite, a quantum chemistry code based on Density Functional Theory. On the Maison de la Simulation side, I contribute to the Kokkos ecosystem with new features that benefit both BigDFT and the broader community. This includes advancing the use of Kokkos within Fortran codebases and environments, and developing new features for KokkosFFT such as callbacks inside FFT computations to enable data manipulation mid-computation.

Previous positions

Before joining the CEA in Grenoble, I was a HPC research engineer at CEA/Saclay (February 2023 – August 2024) at Laboratoire Génie Logiciel, where I parallelized Ondo, a high-order spectral finite element solver for wave propagation modelling, distributing it across distributed-memory architectures.

Before that, I spent three years in the ALPINES team at INRIA Paris, a joint team with the Laboratoire Jacques Louis Lions (LJLL) at Sorbonne Université. There I developed 2-level preconditioning techniques for the map-making problem in cosmology (cosmic microwave background). More details on the dedicated page: B3DCMB.

Teaching

From 2018 to 2020, alongside my research at INRIA, I taught applied mathematics at Sorbonne Université: the finite element method in Python, ordinary differential equations in Python, and linear equation solvers in C++. Those courses are still available in the Teaching section of this site.

More recently I put together a Git tutorial aimed at researchers and students who want to get started with version control in a scientific workflow.

Useful resources

If you are interested in GPU programming with CUDA and Kokkos, have a look at Rémi Bourgeois’ blog.

InfoMath is a seminar series on digital tools for mathematicians (Git, formal mathematics with Lean, scientific computing, and more), hosted by Sorbonne Université and Paris-Dauphine. A great resource if you want to get up to speed on modern computational workflows in a mathematical context.

Download my resumé.