Gyselalib++: A Portable C++ Library for Semi-Lagrangian Kinetic and Gyrokinetic Simulations

Gyselalib++ provides the mathematical building blocks to construct kinetic or gyrokinetic plasma simulation codes in C++, simulating a distribution function discretised in phase space on a fixed grid.It relies on the Discrete Domain Computation (DDC) library (Padioleau et al., 2025) to statically type the discretisation dimensions, thus preventing many common sources of errors.Via DDC, Gyselalib++ also leverages the Kokkos framework (Trott et al., 2022), ensuring performance portability across various CPU and GPU architectures.The library provides a variety of tools including semi-Lagrangian advection operators, quadrature rules, and solvers for elliptic and hyperbolic partial differential equations (PDEs).The majority of the operators are designed to work on non-orthonormal coordinate systems; those that don't use the static typing to raise compiler errors preventing their misuse.