update the free-vibration test

src/felupe/mechanics/_free_vibration.py

@@ -24,7 +24,7 @@
 
 
 class FreeVibration:
-    """A Free-Vibration Step.
+    """A Free-Vibration Step/Job.
 
     Parameters
     ----------
@@ -33,23 +33,30 @@ class FreeVibration:
         matrices.
     boundaries : dict of Boundary, optional
         A dict with :class:`~felupe.Boundary` conditions (default is None).
+    
+    Notes
+    -----
+    ..  note::
+        
+        Boundary conditions with non-zero values are not supported.
 
     Examples
     --------
     ..  pyvista-plot::
 
         >>> import felupe as fem
         >>> import numpy as np
-        >>> from scipy.sparse.linalg import eigsh
         >>>
         >>> mesh = fem.Rectangle(b=(5, 1), n=(50, 10))
         >>> region = fem.RegionQuad(mesh)
         >>> field = fem.FieldContainer([fem.FieldPlaneStrain(region, dim=2)])
         >>>
         >>> boundaries = dict(left=fem.Boundary(field[0], fx=0))
-        >>> dof0, dof1 = fem.dof.partition(field, boundaries)
-        >>>
-        >>> solid = fem.SolidBody(umat=fem.LinearElastic(E=2.5, nu=0.25), field=field)
+        >>> solid = fem.SolidBody(fem.LinearElastic(E=2.5, nu=0.25), field, density=1.0)
+        >>> modal = fem.FreeVibration(items=[solid], boundaries=boundaries).evaluate()
+        >>> 
+        >>> eigenvector, frequency = modal.extract(n=4, inplace=True)
+        >>> solid.plot("Stress", component=0).show()
     """
 
     def __init__(self, items, boundaries=None):

tests/test_free_vibration.py

@@ -39,8 +39,8 @@ def test_free_vibration():
     umat = fem.NeoHooke(mu=1, bulk=2)
     solid = fem.SolidBody(umat=umat, field=field, density=1.5e-9)
 
-    job = fem.FreeVibration([solid]).evaluate(x0=field)
-    new_field, frequency = job.extract(x0=field, n=-1, inplace=False)
+    job = fem.FreeVibration([solid]).evaluate()
+    new_field, frequency = job.extract(n=-1, inplace=False)
 
 
 def test_free_vibration_mixed():