GetFEM is an open source library based on collaborative development.
It aims to offer the most flexible framework for solving potentially coupled
systems of linear and nonlinear partial differential equations with the finite
element method. GetFEM is interfaced
with some script languages (Python, Octave, Scilab and Matlab) so that almost
all of the functionalities can be used just writing scripts. It works in
arbitrary dimension and allow to couple 1D, 2D and 3D problems. The strong
points of GetFEM can be summarized as follows:

  A weak form language (in terms of operators) that allows to translate quite
  arbitrary weak formulations. A symbolic derivation that allows to
  automatically obtain the tangent system for nonlinear problems. A compilation
  of assembly terms into optimized basic instructions.

  A model description that gather the variables, data and terms of a problem
  and some predefined bricks representing classical models : elasticity in
  small and large deformations, Helmholtz problem, scalar elliptic problem,
  Dirichlet, contact and Neumann boundary conditions, incompressibility
  constraint, ...

  A complete separation between geometric transformation, finite element
  method, integration methods and partial differential term description, which
  allows to easily switch from a method to another.

  A large set of predefined methods :
  isoparametric/subparametric/overparametric elements, Pk on simplices of
  arbitrary degree and dimension, Qk on parallelepipeds, pyramidal elements,
  P1, P2 with bubble functions, Hermite elements, Argyris element, HCT and FVS,
  elements with hierarchical basis (for multigrid methods for instance),
  discontinuous Pk and Qk, vector elements (RT0, Nedelec) ...

  A large set of predefined integration methods.
  Structural mechanics terms (elasticity, contact with friction, plasticity ...)
  Level-set and finite element cut by one or several level-set (Xfem)
  
  Computation of terms between two meshes with an arbitrary transformation:
  this is a very powerful tool of the generic assembly that allows to use a
  parameterized transformation. The derivative of the transformation with
  respect to the potential dependance in the variables is taken into account.
  Possible use : contact problems, fluid-structure interaction, special
  boundary conditions ...

  Post-processing directly with Scilab, Octave or Matlab interfaces or with
  the export of vtk or gmsh files. Many possibility to interpolate arbitrary
  quantities, make slices, projections ...

GetFEM can be used to construct very generic finite element codes, where
finite element methods, integration methods and the dimension of the problem
are the parameters that can be changed very easily. This allows a wide range
of experiments. Many examples and demos are provided.

GetFEM has only an experimental meshing procedure (and produces regular meshes).
It is therefore often necessary to import meshes. The formats currently
supported are GID, GMSH, EMC2 and ANSYS. 


Please read INSTALL and see the site https://getfem.org/