REST: Embracing the Rust Programming Language for Modern Electronic Structure Theory^†

REST (Rust-based electronic structure toolkit) is a modern open-source electronic structure code entirely written in Rust, combining high performance, memory safety, and expressive concurrency. As a community-driven project, its source code is freely available at https://gitee.com/restgroup, fostering open collaboration and transparent development. It supports a wide range of density functional methods—from local density approximation (LDA), generalized gradient approximation (GGA), meta-GGA, and hybrids to doubly hybrids, as well as machine learning-augmented functionals—enabling high-accuracy simulations with low computational overhead. Its “disk-free” RI-based (RI: resolution-of-the-identity) implementation and efficient shared-memory parallelism (via Rayon) ensure rapid calculations even for challenging systems. REST also offers unique user support through large language model-assisted input generation and developer-friendly tensor libraries for rapid algorithm prototyping.