FreeFEM is a partial differential equation solver for non-linear multi-physics systems in 2D and 3D using the finite element method.

Problems involving partial differential equations from several branches of physics such as fluid-structure interactions require interpolations of data on several meshes and their manipulation within one program.

FreeFEM includes a fast interpolation algorithm and a language for the manipulation of data on multiple meshes. It is written in C++ and the FreeFEM language is a C++ idiom.