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Add multi-precision type MPFRField based on mpreal and mpfr

Simon Praetorius requested to merge issue/replace_gmp_bc_mpfr into master


In addition to the outdated GMPField class a new multi-precision field type MPFRField, based on the mpfr::mpreal class from the MPFR-C++ library, is added.


The old gmpcxx library lacks some implementations, e.g. of numeric_limits. Since the GMP library also recommends to switch to the (more up-to-date) library MPFR (See and for floating point arithmetic, I switched the backend from GMP to MPFR. The C++ wrapper is chosen to be MPFR-C++ ( since it is used in several other libraries, e.g. Eigen, boost::multiprecision. It can be used as a floating-point type in the Eigen linear algebra library and has much better support for std::numeric_limits.

Since in the Dune GMPField implementation, the precision is given by a template parameter, some numeric_limits constants can be filled with concrete values.

The MPFR and MPFR-C++ library are available in the Ubuntu and Debian repositories (libmpfr-dev and libmpfrc++-dev).

  • Add packages for libmpfr and libmpfrc++ to docker images for the CI system.


To allow a smooth transition time, the GMPField type is still available, but deprecated. (Maybe we can just leave it in dune-common without deprecation). Step-by-step the use of GMP in downstream modules will be changed to MPFR. Once this is tested in downstream modules, we can make GMPField and alias of MPFRField and eventually remove that type.


This MR is based on the old MR !565 (closed) that was done from a personal fork that cannot be used in connected multi-repo pipelines. Thus, the branch is uploaded now directly into the dune-common repository.

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