Section: Software

MONTJOIE

Montjoie is a software for the efficient and accurate wave propagation numerical modeling in both time dependent or time harmonic regimes in various domains of application : acoustics, aeroacoustics, elastodynamics and electromagnetism. It is based essentially on the use of hexahedral-dominant (including a small part of tetrahedra, pyramids and prisms) conforming meshes and continuous or discontinuous Galerkin approximations. The use of tensor product basis functions coupled to appropriate numerical quadrature techniques leads to important gains in both computing time and memory storage. Various techniques for treating unbounded domains have been incorporated : DtN maps, local absorbing conditions, integral representations and PMLs.

We have written an interface for the use of other libraries : SELDON, a C++ linear algebra library (interfaced with BLAS and LAPACK) used for iterative linear solvers, MUMPS, PASTIX and UMFPACK for sparse direct solvers, ARPACK for eigenvalue computation, METIS and SCOTCH for mesh decomposition. Except for trivial geometries, the mesh generation is not part of the code. It can be done with Modulef, Gmsh, Ghs3D or Cubit.

This code has been developed by Marc Duruflé during his PhD thesis (in 2006). Some other contributors have brought more specific enrichments to the code. The online documentation is available at :

http://montjoie.gforge.inria.fr/ .

The main contributions of 2010 have been the following :

• parallelization of the interface with ARPACK,

• unitary tests for SELDON and Montjoie aiming at stabilizing the code,

• implementation of $H\left(div\right)$ finite elements in 2D and 3D in collaboration with Morgane Bergot,

• optimization of the numerical simulation of the piano in collaboration with Juliette Chabassier (multithreading for the string nonlinear equations, improvement of the parallelization).