TODO

@TODO

- Adaptive gridding
  It would be optimal if I could Include the adaptive 
  grid routines in my inversion code. One essentially just
  provides the basic matrices, and the projection will be
  done automatically

- Cummulative sensitivity
  A routine to compute cummulative sensitivity for each 
  model parameter would be nice to have

- Some improvements to xdmf output needed:
  It would be a bit better to uniquify the vertices in 
  xdmf output, at the moment there are redundant points

- Solution should be pssibly be saved...
  as a 1 to 4 column file, might be quite useful as an 
  additional option instead of separate files

- Add numerous sanity checks!
  Everything is somewhat unstable at the moment, add 
  warnings etc, when parameters are chosen incorrectly   

- Post-processing module needs to be extended!
  logarithmic likeliehood, and AKAIKE information criteria

      * Output of rough and varr needs to be truncated
      * Clean up a little bit remove the b_??? vectors

- build routine that adds random noise to rhs

- Module to compute resolution matrix

- Compare solvers and their convergence

- Variance reduction hypothesis tests