mp++ is a C++11/14/17/20 library for multiprecision arithmetic, featuring:

  • arbitrary-precision integers,

  • arbitrary-precision rationals,

  • quadruple-precision floats,

  • quadruple-precision complex numbers,

  • arbitrary-precision floats,

  • arbitrary-precision complex numbers.

Design goals include:

  • excellent performance for small integer and rational operands,

  • easy embeddability in computer algebra systems and generic C++ libraries,

  • a large collection of arbitrary-precision special functions,

  • an ergonomic API based on modern C++ idioms.

Design non-goals include:

Built on top of the GNU multiprecision stack (GMP, MPFR, MPC), mp++ was initially conceived as a GMP wrapper with special focus on performance with small operands. In particular, a small buffer optimisation and custom implementations of basic mathematical primitives are instrumental in achieving a performance increase, with respect to GMP and other integer multiprecision libraries, which can be substantial (see the benchmarks section).

Over time, mp++ has accrued many additional features, including multiprecision real and complex number types, and an expanding library of special functions (built in part on top of the excellent Arb library).

mp++ is a spinoff of the Piranha library, released under the MPL2 license. If you are using mp++ as part of your research, teaching, or other activities, we would be grateful if you could star the repository and/or cite our work. The DOI of the latest version and other citation resources are available at this link.


mp++ is under active development, and, although we try not to break the API gratuitously, backwards-incompatible changes do happen from time to time. The API will be stabilised with the upcoming release of version 1.0.


This documentation refers to the latest development version of mp++, and it may describe features not yet available in mp++’s stable releases.