[ ] Given a mesh write function that assigns value of conductivities $\sigma$ to coordinates given mesh coordinates. Store vector according to the ordering given by the coordinates.
[ ] Write the function that can save this again in an Array.
[ ] Write function that returns $K$ matrix of for neumann and dirichlet map given above information and the weakform (prefereably Gridap.)
[ ] Implement LU and CG solver to update solution
[ ] Implement function that updates $K$ given slight alteration in $\sigma$.
[ ] Solve Inverse Problem with Total variation reconstruction
[ ] Find way to represent NtD and DtN Operator. ()