HPC / C++ Software Engineer – Kokkos, GPU Computing

CEA Paris-Saclay, France | 36-month fixed-term contract | Starting January 2027

Join us to shape the future of exascale computing!

CEA Paris-Saclay, France | 36-month fixed-term contract | Starting January 2027

Join us to shape the future of exascale computing!

The French Alternative Energies and Atomic Energy Commission (CEA) is recruiting an HPC / C++ Software Engineer to contribute to KOKTAILS , a research project within the French NumPEx programme (France 2030), dedicated to advancing the Kokkos ecosystem for next-generation supercomputers.

This position offers a unique opportunity to work at the intersection of high-performance computing, GPU programming, scientific software development, complex data structures, and compiler technologies .

You will contribute to open-source software used by scientific computing communities, collaborate with national and international research teams, and help develop portable and efficient programming solutions for heterogeneous CPU/GPU architectures.

Your missions

Your work will focus on three complementary research and development areas:

1. Cross-cutting Kokkos developments (WP5)

• Design, develop, and maintain reusable C++ components within the Kokkos ecosystem.
• Improve performance portability across CPU and GPU architectures, including CUDA, HIP, SYCL, and OpenMP.
• Develop generic computing and data abstractions, interfaces, benchmarks, and performance analysis tools.
• Contribute to the international open-source Kokkos community.
• Implement software engineering best practices, including automated testing, continuous integration, and packaging.

2. High-dimensional and unstructured meshes (WP3)

• Develop efficient data structures for high-dimensional scientific applications, including 6D/7D data representations.
• Optimize multidimensional data layouts, memory access patterns, and indexing strategies using Kokkos.
• Investigate GPU-efficient algorithms for unstructured meshes, irregular memory accesses, connectivity management, and hierarchical parallelism.
• Address challenges related to load balancing, concurrent memory access, and heterogeneous execution.
• Evaluate solutions through representative scientific kernels, benchmarks, and mini-applications.

3. Python-Kokkos interoperability and MLIR (WP2)

• Develop and prototype Python/C++ interfaces for executing Kokkos computational kernels.
• Investigate efficient data exchange between Python environments and GPU memory.
• Explore compiler-based approaches using LLVM/MLIR to translate and optimize computational kernels for Kokkos.
• Study interoperability with scientific Python and AI frameworks, including JAX and PyTorch.
• Evaluate performance, usability, and integration of these approaches within scientific simulation workflows.

You will also collaborate with other KOKTAILS partners and NumPEx projects, particularly Exa-DI and Exa-SofT, to validate and integrate new software components into scientific applications.

Your profile

We are looking for a motivated software engineer or researcher with a Master's degree, engineering degree, or PhD in Computer Science, Scientific Computing, Applied Mathematics, or a related field.

Required skills:

• Strong proficiency in modern C++ (C++17 or later).
• Good understanding of parallel programming and/or performance optimization.
• Experience with collaborative software development (Git, CMake, testing, CI/CD).
• Interest in high-performance computing and scientific software.

Highly appreciated:

• Experience with Kokkos, MPI, OpenMP, CUDA, HIP, or SYCL.
• Knowledge of CPU/GPU architectures and heterogeneous computing.
• Python programming and scientific computing environments.
• GPU profiling and performance optimization.

Additional assets:

• LLVM/MLIR compiler infrastructure.
• JAX, PyTorch, or pybind11.
• High-dimensional or unstructured mesh data structures.
• Numerical methods (finite volumes, finite elements).
• HPC software deployment tools such as Spack.

You should enjoy solving challenging technical problems, working collaboratively within international teams, and contributing to open-source scientific software. Professional English proficiency is expected.

Why join CEA?

• Contribute to an ambitious national research programme preparing European scientific applications for exascale computing.
• Work on open-source technologies at the forefront of HPC and GPU programming.
• Collaborate with leading French, European, and international research teams.
• Participate in technical workshops, training activities, and international conferences.
• Benefit from the CEA research environment, professional development opportunities, competitive compensation based on experience, and applicable remote-working arrangements.

Location: CEA Paris-Saclay, Gif-sur-Yvette, France

Contract: 36-month fixed-term contract

Expected starting date: January 2027

Join us in developing the next generation of portable, high-performance scientific software!

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