Fig. 2.

Assembly of the system matrix: The 4 × 4 stiffness-, mass- and boundary mass-matrices K, M, and R of every element are scaled with the optical parameters κ, μ and ρ, summed and stored temporarily into a vector T. In a second step, these elements are compressed into a sparse matrix A by summing the elements specified by the vertex-to-element connectivity which is given as look-up table (LUT).