Reorder Everything.

[DanielBoigk]

• 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. ()
• Use representation for neural operator