Welcome to mp++’s documentation!

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

  • arbitrary-precision integers,
  • arbitrary-precision rationals,
  • arbitrary-precision floats,
  • quadruple-precision floats.

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.

Design non-goals include:

Based on well-known libraries such as GMP, MPFR, and others, mp++ was initially conceived as a GMP wrapper with a 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).

Eventually, a multiprecision rational class and two multiprecision floating-point classes were added, and today a secondary objective of mp++ is to provide a modern, consistent and unified C++ interface to several lower-level multiprecision libraries.

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.