def solve_poisson_robin(self, p=1, n=1, plot=True):
pde = XYData()
mesh = pde.init_mesh(n=n)
node = mesh.node
cell = mesh.entity("cell")
name = 'RobinBCTest.mat'
space = LagrangeFiniteElementSpace(mesh, p=p)
A = space.stiff_matrix()
F = space.source_vector(pde.source)
# print(A.toarray())
# A, F = space.set_robin_bc(A, F, pde.robin)
uh = space.function()
#bc = BoundaryCondition(space, robin=pde.robin)
A, b = space.set_robin_bc(A, F, pde.robin)
uh[:] = spsolve(A, b).reshape(-1)
error = space.integralalg.L2_error(pde.solution, uh)
print(error)
# print('A:', A.toarray())
# print('F:', F)
if plot:
fig = plt.figure()
axes = fig.gca()
mesh.add_plot(axes)
mesh.find_node(axes, showindex=True)
mesh.find_cell(axes, showindex=True)
plt.show()
def solve_poisson_robin(self, p=1, n=1, plot=True):
pde = XYData()
mesh = pde.init_mesh(n=1)
space = LagrangeFiniteElementSpace(mesh, p=p)
A = space.stiff_matrix()
F = space.source_vector(pde.source)
space.set_robin_bc(A, F, pde.robin)
print('A:', A.toarray())
print('F:', F)
if plot:
fig = plt.figure()
axes = fig.gca()
mesh.add_plot(axes)
mesh.find_node(axes, showindex=True)
mesh.find_cell(axes, showindex=True)
plt.show()
def solve_poisson_robin(self, p=1, n=1, plot=True):
pde = CosCosCosData()
mesh = pde.init_mesh(n=n)
space = LagrangeFiniteElementSpace(mesh, p=p)
A = space.stiff_matrix()
F = space.source_vector(pde.source)
uh = space.function()
bc = BoundaryCondition(space, robin=pde.robin)
A, b = space.set_robin_bc(A, F, pde.robin)
uh[:] = spsolve(A, b).reshape(-1)
error = space.integralalg.L2_error(pde.solution, uh)
print(error)
