def _(V: fem.FunctionSpace, entities=None):
"""Creates a vtk mesh topology (topology array and array of cell
types) that is based on degree of freedom coordinate. Note that this
function supports Lagrange elements (continuous and discontinuous)
only.
"""
family = V.ufl_element().family()
if not (family in ['Discontinuous Lagrange', "Lagrange", "DQ", "Q"]):
raise RuntimeError(
"Can only create meshes from Continuous or Discontinuous function-spaces"
)
if V.ufl_element().degree() == 0:
raise RuntimeError("Cannot create topology from cellwise constants.")
mesh = V.mesh
if entities is None:
num_cells = mesh.topology.index_map(mesh.topology.dim).size_local
entities = np.arange(num_cells, dtype=np.int32)
else:
num_cells = entities.size
dofmap = V.dofmap
num_dofs_per_cell = V.dofmap.dof_layout.num_dofs
degree = V.ufl_element().degree()
cell_type = mesh.topology.cell_type
if family == "Discontinuous Lagrange":
perm = np.array(_perm_dg[cell_type][degree], dtype=np.int32)
elif family == "DQ":
perm = np.array(_perm_dq[cell_type][degree], dtype=np.int32)
else:
perm = np.argsort(cpp.io.perm_vtk(cell_type, num_dofs_per_cell))
if degree == 1:
cell_types = np.full(num_cells,
_first_order_vtk[mesh.topology.cell_type])
else:
warnings.warn("Plotting of higher order functions is experimental.")
cell_types = np.full(num_cells,
cpp.io.get_vtk_cell_type(mesh, mesh.topology.dim))
topology = np.zeros((num_cells, num_dofs_per_cell + 1), dtype=np.int32)
topology[:, 0] = num_dofs_per_cell
dofmap_ = dofmap.list.array.reshape(dofmap.list.num_nodes,
num_dofs_per_cell)
topology[:, 1:] = dofmap_[:num_cells, perm]
return topology.reshape(1, -1)[0], cell_types
def _(V: fem.FunctionSpace, entities=None):
"""Creates a VTK mesh topology (topology array and array of cell
types) that is based on the degree-of-freedom coordinates. Note that
this function supports Lagrange elements (continuous and
discontinuous) only.
"""
if not (V.ufl_element().family()
in ['Discontinuous Lagrange', "Lagrange", "DQ", "Q"]):
raise RuntimeError(
"Can only create meshes from continuous or discontinuous Lagrange spaces"
)
degree = V.ufl_element().degree()
if degree == 0:
raise RuntimeError("Cannot create topology from cellwise constants.")
# Use all local cells if not supplied
msh = V.mesh
tdim = msh.topology.dim
if entities is None:
entities = range(msh.topology.index_map(tdim).size_local)
dofmap = V.dofmap
num_dofs_per_cell = V.dofmap.dof_layout.num_dofs
cell_type = msh.topology.cell_type
perm = np.argsort(_cpp.io.perm_vtk(cell_type, num_dofs_per_cell))
vtk_type = _first_order_vtk[
cell_type] if degree == 1 else _cpp.io.get_vtk_cell_type(
cell_type, tdim)
cell_types = np.full(len(entities), vtk_type)
topology = np.zeros((len(entities), num_dofs_per_cell + 1), dtype=np.int32)
topology[:, 0] = num_dofs_per_cell
dofmap_ = dofmap.list.array.reshape(dofmap.list.num_nodes,
num_dofs_per_cell)
topology[:, 1:] = dofmap_[:len(entities), perm]
return topology.reshape(1, -1)[0], cell_types, V.tabulate_dof_coordinates()
