2021 Volume 29 Pages 676-684
The GNU MPFR library for arbitrary-precision floating-point arithmetic is widely used, and its Foreign Function Interface bindings to various languages have been developed. For the Rust programming language, existing bindings to the MPFR library include gmp-mpfr-sys (a low-level binding) and Rug (a binding that utilizes gmp-mpfr-sys to provide a more user-friendly interface). However, neither has sufficient descriptiveness and performance as bindings for general users of Rust, which is a programming language featuring high memory safety and high speed. We have developed a Rust binding, Rumpfr, to the MPFR library, that offers an easy way to write programs that perform high-speed multiple-precision floating-point computation. Rumpfr provides an interface that follows that of the MPFR library but hides the complexity of managing the mantissa area of floating-point numbers from the user. Rumpfr uses Rust's variable-length arrays to allocate mantissa areas, making it easy to handle without compromising Rust's high memory safety. In this paper, we describe the design and implementation of Rumpfr and present the results of numerical experiments demonstrating that Rumpfr can be used to write programs with low overhead.