def mesh_randomizer_2d(mesh, percentage, preserve_boundary=True):
"""
Randomly perturb a given mesh.
Args:
mesh: Input mesh.
percentage: Maximum perturbation in percentage of mesh.hmin().
preserve_boundary: Whether to move the vertices on the boundary.
Returns:
rmesh: The perturbed mesh.
"""
# Generate a deep copy of the mesh
rmesh = Mesh(mesh)
meshsize = rmesh.hmin()
# Randomly perturbed the mesh
radius = np.random.rand(rmesh.num_vertices()) * percentage * meshsize
theta = np.random.rand(rmesh.num_vertices()) * 2.0 * np.pi
deltax = np.zeros([rmesh.num_vertices(), 2])
deltax[:, 0] = (radius * np.sin(theta)).transpose()
deltax[:, 1] = (radius * np.cos(theta)).transpose()
# What to do with the boundary vertices
if preserve_boundary:
# Exterior means global boundary
boundary_mesh = BoundaryMesh(rmesh, "exterior")
# entity_map contains the indices of vertices on the boundary
boundary_vertices = boundary_mesh.entity_map(0).array()
deltax[boundary_vertices] = 0.0
rmesh.coordinates()[:] = rmesh.coordinates() + deltax
return rmesh
def gaussian_mesh_randomizer(mesh, percentage, preserve_boundary=True):
"""
Randomly perturb a given mesh.
Args:
mesh: Input mesh.
percentage: Maximum perturbation in percentage of mesh.hmin().
preserve_boundary: Whether to move the vertices on the boundary.
Returns:
rmesh: The perturbed mesh.
"""
rmesh = Mesh(mesh)
deltax = (np.random.randn(rmesh.num_vertices(),
rmesh.geometry().dim()) * percentage *
rmesh.hmin())
if preserve_boundary:
boundary_mesh = BoundaryMesh(rmesh, "exterior")
boundary_vertices = boundary_mesh.entity_map(0).array()
deltax[boundary_vertices] = 0.0
rmesh.coordinates()[:] = rmesh.coordinates() + deltax
return rmesh
