poisson.form

利用C

element = FiniteElement("Discontinuous Lagrange", "tetrahedron", 1)

v = TestFunction(element)
u = TrialFunction(element)
f = Function(element)

gamma = 24.0
alpha = 8.0

n = FacetNormal("tetrahedron")
h = MeshSize("tetrahedron")

#a = dot(grad(v), grad(u))*dx \
#   + alpha*avg(h)*dot(jump(v, n), jump(u, n))*dS \
#   + gamma*h*v*u*ds

#   + alpha/h('+')*dot(jump(v, n), jump(u, n))*dS \
#   + alpha*avg(h)*dot(jump(v, n), jump(u, n))*dS \


a = dot(grad(v), grad(u))*dx \
   - dot(avg(grad(v)), jump(u, n))*dS \
   - dot(jump(v, n), avg(grad(u)))*dS \
   + alpha/h('+')*dot(jump(v, n), jump(u, n))*dS \
   - dot(grad(v), mult(u,n))*ds \
   - dot(mult(v,n), grad(u))*ds \
   + gamma/h*v*u*ds

L = v*f*dx