eigen_modes
'''''''''''

In ``eigen_modes`` it is shown how to compute the eigen modes. The mode can be specify with the ``-m`` argument. Simulation is performed on a bar where a pulse is imposed.
The ``-p`` will plot the following figures :numref:`fig-ex-eigen`:

.. _fig-ex-eigen:
.. figure:: examples/python/solid_mechanics_model/eigen_modes/images/eigen_modes.png
:align: center
:width: 70%

Energy norms as a fonction of time (left), space-time diagram for diplacements (center) and space-time
diagram for velocities (right) with the default values.