| Procedure | Location | Procedure Type | Description |
|---|---|---|---|
| material | feigen | Function | Isotropic elasticity matrix in Voigt notation: bar (1D), plane strain (2D), solid (3D) |
| modes | feigen | Subroutine | Ascending eigenvalues and orthonormal eigenvectors of symmetric K; eigenvalues below tol*max|lambda| (default 1e-10) are set to exactly zero |
| name_modes | feigen | Subroutine | Replace the eigenvectors of each group of equal eigenvalues (within tol*max|lambda|, default 1e-8) by the projections of the best-matching catalog fields onto that eigenspace. match is the cosine between field and eigenspace. |
| plot_modes | feigen | Subroutine | Write one PNG, SVG or PDF (chosen by the extension of filename) with a subplot per mode: undeformed (black), deformed (green), nodal displacements (blue) |
| stiffness | feigen | Function | Stiffness matrix K = sum_g B^T D B det(J) w_g, dofs ordered node by node |