Hi FEniCS family,
I am working on on the following variational statement taken from
Ve = VectorElement("CG", mesh.ufl_cell(), 2) Re = VectorElement("R", mesh.ufl_cell(), 0) W = FunctionSpace(mesh, MixedElement([Ve, Re]), constrained_domain=PeriodicBoundary(vertices, tolerance=1e-10)) V = FunctionSpace(mesh, Ve) v_,lamb_ = TestFunctions(W) dv, dlamb = TrialFunctions(W) w = Function(W) dx = Measure('dx')(subdomain_data=subdomains) Eps = Constant(((0, 0), (0, 0))) F = sum([inner(sigma(dv, i, Eps), eps(v_))*dx(i) for i in range(nphases)]) a, L = lhs(F), rhs(F) a += dot(lamb_,dv)*dx + dot(dlamb,v_)*dx
For the variational statement
a, L = lhs(F), rhs(F), the FEniCS find a linear equation (using FFC ) and after solve
(a==L,w,) give output of fluctuation function, w for each node.
I wanted to find the linear system of equation generated by FEniCS (like Ax=b, with x=w being the fluctuation function). I want to use coefficient matrix A for my post processing.
I know that, FFC forms a C++ code from symbolic variational statement, and after solution gives back, function w in python format. So, there must be some linear equation which is generated to solve the variational form (a==L). Kindly tell me, how I can get access to the linear system of equation (coeff matrix, A being assembled over all elements of mesh, through guassian quadrature) and interpret it for usage.
Any help is greatly appreciated.