I am trying to define some matrices for my FEM and I think I am misunderstanding how to use some of the ngsolve functions.
The listing below defines my geometry and the objects for FEM, then below I define the usual mass and stiffness matrices with entries like u*v and grad(u)*grad(v), and these work fine. My issue is defining this matrix b which will have entries like grad(u)*v. With the code I have below I get an error, so how should I be defining this?
#generate mesh and finite element materials
geo = SplineGeometry()
geo.AddRectangle( (-D, -D), (D, D), bcs = (“bottom”, “right”, “top”, “left”))
mesh = Mesh( geo.GenerateMesh(maxh=msize))
fes = H1(mesh, order=1, dirichlet=“bottom|right|left|top”)
u = fes.TrialFunction()
v = fes.TestFunction()
#generate stiffness and mass matrices
Thanks for any help