RELEASE_NOTES

This version of the code is a major upgrade that includes:

1. Completely redefined underlying data structure using types (classes) and overloading of operators
   to allow for operating directly on the types. There are now three classes, one for the model state,
   one for the model parameters, and one for diagnostic variables.  Check the files:
      mod_states.F90, mod_params.F90, and mod_diag.F90
   The main benefit is the simple representation of the equations in the function f at the end
   of seir.F90, and the reference to different model variables in the measurement operator and for
   diagnostocs.

2. Another equation is added to the system, representing the fatally ill while in hospital. This gives 
   a more realistic representation of the number of hospitalized. In fact with the new data structure
   it took five min to update the model with another equation.

3. The code now allows for reading input files
      infile.in      (input parameters: Note change in order of lines since previous version.)
      corona.in      (previously corona.dat)
      agegroups.in   (definition of agegroups and population per age group) 
      pfactors.in    (the fractions of mild, severe, fatal desease per agegroup)
      Rmatrix.in     (the transmission factors between agegroups after second intervention, for predictions)
   The three last files are generated automatically (with Norwegian numbers) unless they are already there.
   Note that the number of agegroups is hard coded in mod_dimensions.F90.