def _generate_face_dofs(self, cell, degree, offset, variant, quad_deg):
"""Generate degrees of freedoms (dofs) for faces."""
# Initialize empty dofs and identifiers (ids)
dofs = []
ids = dict(list(zip(list(range(4)), ([] for i in range(4)))))
# Return empty info if not applicable
d = cell.get_spatial_dimension()
if (degree < 2):
return (dofs, ids)
msg = "2nd kind Nedelec face dofs only available with UFC convention"
assert isinstance(cell, UFCTetrahedron), msg
# Iterate over the faces of the tet
num_faces = len(cell.get_topology()[2])
for face in range(num_faces):
# Construct quadrature scheme for this face
m = 2 * (degree + 1)
Q_face = UFCTetrahedronFaceQuadratureRule(face, m)
# Construct Raviart-Thomas of (degree - 1) on the
# reference face
reference_face = Q_face.reference_rule().ref_el
RT = RaviartThomas(reference_face, degree - 1, variant)
num_rts = RT.space_dimension()
# Evaluate RT basis functions at reference quadrature
# points
ref_quad_points = Q_face.reference_rule().get_points()
num_quad_points = len(ref_quad_points)
Phi = RT.get_nodal_basis()
Phis = Phi.tabulate(ref_quad_points)[(0, 0)]
# Note: Phis has dimensions:
# num_basis_functions x num_components x num_quad_points
# Map Phis -> phis (reference values to physical values)
J = Q_face.jacobian()
scale = 1.0 / numpy.sqrt(numpy.linalg.det(numpy.dot(J.T, J)))
phis = numpy.ndarray((d, num_quad_points))
for i in range(num_rts):
for q in range(num_quad_points):
phi_i_q = scale * numpy.dot(J, Phis[numpy.newaxis, i, :, q].T)
for j in range(d):
phis[j, q] = phi_i_q[j]
# Construct degrees of freedom as integral moments on
# this cell, using the special face quadrature
# weighted against the values of the (physical)
# Raviart--Thomas'es on the face
dofs += [IntegralMoment(cell, Q_face, phis)]
# Assign identifiers (num RTs per face + previous edge dofs)
ids[face] = list(range(offset + num_rts*face, offset + num_rts*(face + 1)))
return (dofs, ids)
def _generate_face_dofs(self, cell, degree, offset):
"""Generate degrees of freedoms (dofs) for faces."""
# Initialize empty dofs and identifiers (ids)
dofs = []
ids = dict(list(zip(list(range(4)), ([] for i in range(4)))))
# Return empty info if not applicable
d = cell.get_spatial_dimension()
if (degree < 2):
return (dofs, ids)
msg = "2nd kind Nedelec face dofs only available with UFC convention"
assert isinstance(cell, UFCTetrahedron), msg
# Iterate over the faces of the tet
num_faces = len(cell.get_topology()[2])
for face in range(num_faces):
# Construct quadrature scheme for this face
m = 2 * (degree + 1)
Q_face = UFCTetrahedronFaceQuadratureRule(face, m)
# Construct Raviart-Thomas of (degree - 1) on the
# reference face
reference_face = Q_face.reference_rule().ref_el
RT = RaviartThomas(reference_face, degree - 1)
num_rts = RT.space_dimension()
# Evaluate RT basis functions at reference quadrature
# points
ref_quad_points = Q_face.reference_rule().get_points()
num_quad_points = len(ref_quad_points)
Phi = RT.get_nodal_basis()
Phis = Phi.tabulate(ref_quad_points)[(0, 0)]
# Note: Phis has dimensions:
# num_basis_functions x num_components x num_quad_points
# Map Phis -> phis (reference values to physical values)
J = Q_face.jacobian()
scale = 1.0 / numpy.sqrt(numpy.linalg.det(numpy.dot(J.T, J)))
phis = numpy.ndarray((d, num_quad_points))
for i in range(num_rts):
for q in range(num_quad_points):
phi_i_q = scale * numpy.dot(J, Phis[numpy.newaxis, i, :, q].T)
for j in range(d):
phis[j, q] = phi_i_q[j]
# Construct degrees of freedom as integral moments on
# this cell, using the special face quadrature
# weighted against the values of the (physical)
# Raviart--Thomas'es on the face
dofs += [IntegralMoment(cell, Q_face, phis)]
# Assign identifiers (num RTs per face + previous edge dofs)
ids[face] = list(range(offset + num_rts*face, offset + num_rts*(face + 1)))
return (dofs, ids)