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Version 4.5: new features

Release, binaries packages

  • Since the version 4.5, the FreeFEM binary packages provides with a compiled PETSc library.
  • FreeFEM is now interfaced with ParMmg.

New meshes and FEM border

After Surface FEM, Line FEM is possible with a new mesh type meshL, P0 P1 P2 P1dc FE, basic FEM, mesh generation. This new development allows to treat a 1d problem, such as a problem described on a 3d curve.

Abstract about Line FEM in FreeFEM.

  • new meshL type, refer to the section The type meshL in 3 dimension

    • new type of surface mesh: meshL

    • the functionalities on the meshL type, it is necessary to load the plugin ”msh3”.

    • generator of meshL segment, define multi border and buildmesh function.

    • basic transformation are avalaible: movemesh, trunc, extract, checkmesh, change, AddLayers, glue of meshL.

      It is possible to build the underlying meshL from a meshS with the function buildBdMesh: ThS=buildBdMesh(ThS) builds the boundary domain associated to the meshS ThS and extract it by the command meshL ThL=ThS. Gamma.

  • new finite element space with curve finite element type

  • FESpace P0 P1, P2, P1dc Lagrange finite elements and possible to add a custumed finite element with the classical method (like a plugin).
  • as in the standard 2d, 3d, surface 3d case, the variational problem associated to surface PDE can be defined by using the keywords
    • problem
    • varf to access to matrix and RHS vector
    • available operators are int1d, on and the operator int0d to define a Neumann boundary condition
  • visualisation tools
    • plot with plot of ffglut, medit meshes meshL and solutions
    • 2d or 3d view, with in 3d the option to visualize the elememt Normals at element (touch ‘T’) and the deformed domain according to it (touch ‘2’).
    • loading, saving of meshes and solution at FreeFEM’s format
      • “.mesh” mesh format file of Medit (P. Frey LJLL)
      • “.msh” for mesh and “.sol” data solution at freefem format
      • “.msh” data file of Gmsh (Mesh generator) (load “gmsh”)
      • vtk format for meshes and solutions (load “iovtk” and use the “.vtu” extension)

Boundary Element Method

Allows to define and solve a 2d/3d BEM formulation and rebuild the associated potential. The document is in construction.

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