for lev in range(ser_ref_levels):
mesh.UniformRefinement()
if mesh.NURBSext:
mesh.SetCurvature(max(order, 1))
bb_min, bb_max = mesh.GetBoundingBox(max(order, 1))
# 6. Define the parallel mesh by a partitioning of the serial mesh. Refine
# this mesh further in parallel to increase the resolution. Once the
# parallel mesh is defined, the serial mesh can be deleted.
pmesh = mfem.ParMesh(MPI.COMM_WORLD, mesh)
for k in range(par_ref_levels):
pmesh.UniformRefinement()
# 7. Define the discontinuous DG finite element space of the given
# polynomial order on the refined mesh.
fec = mfem.DG_FECollection(order, dim)
fes = mfem.ParFiniteElementSpace(pmesh, fec)
global_vSize = fes.GlobalTrueVSize()
if myid == 0:
print("Number of unknowns: " + str(global_vSize))
#
# Define coefficient using VecotrPyCoefficient and PyCoefficient
# A user needs to define EvalValue method
#
class velocity_coeff(mfem.VectorPyCoefficient):
def EvalValue(self, x):
dim = len(x)
np.floor(np.log(5000. / mesh.GetNE()) / np.log(2.) / dim))
for x in range(ser_ref_levels):
mesh.UniformRefinement()
# Since NURBS meshes do not support DG integrators, we convert them to
# regular polynomial mesh of the specified (solution) order.
if (mesh.NURBSext): mesh.SetCurvature(order)
pmesh = mfem.ParMesh(MPI.COMM_WORLD, mesh)
del mesh
for x in range(par_ref_levels):
pmesh.UniformRefinement()
# 4. Define a DG vector finite element space on the mesh. Here, we use
# Gauss-Lobatto nodal basis because it gives rise to a sparser matrix
# compared to the default Gauss-Legendre nodal basis.
fec = mfem.DG_FECollection(order, dim, mfem.BasisType.GaussLobatto)
fespace = mfem.ParFiniteElementSpace(pmesh, fec, dim, mfem.Ordering.byVDIM)
glob_size = fespace.GlobalTrueVSize()
if (myid == 0):
print('Number of finite element unknowns: ' + str(glob_size))
print('Assembling:')
# 5. In this example, the Dirichlet boundary conditions are defined by
# marking boundary attributes 1 and 2 in the marker Array 'dir_bdr'.
# These b.c. are imposed weakly, by adding the appropriate boundary
# integrators over the marked 'dir_bdr' to the bilinear and linear forms.
# With this DG formulation, there are no essential boundary conditions.
ess_tdof_list = mfem.intArray()
dir_bdr = mfem.intArray(pmesh.bdr_attributes.Max())
dir_bdr.Assign(0)