====== Program Flow ======

In the following the program flow of some important functions is sketched


===== Reflectivity =====

  - Read current state from the graphical user interface and check values.
  - if "Set optical constants automatically is turned on"
    - Read .db or .e files of each layer. If no file found display error message.
    - if magnetization is turned on read .m files of each layer. If no file found display error message.
  - Fill dielectric tensor with proper values of the diagonal and off-diagonal elements.
  - Run script ("BeforeCalculation")
  - Calculate reflectivity
  - Apply post modifications

===== Calculation of the error for each dataset =====

  - Check if fit flag is set, otherwise return
  - Make a private copy of the dataset
  - Apply qz-shift, energy-shift, scaling and translation to the datasets energy table and qz table.
  - Apply post-modifications to the dataset.
  - Check, which type of dataset this is. This depends on the data in the dataset. The priority is reflectivity > asymmetry > Rp and Rm. Separate datasets if you want to calculate the different curves. 
  - Calculate the corresponding curve for the same datapoints as the measurement. (This is equivalent to the "use dataset points for simulatio"
  - Calculate Chi^2 between dataset and simulation.

===== Energy scan =====



===== Show Delta and Beta Spectra =====


===== Script Execute =====