Documentation hints when using doxygen

• There are several formats how to specify a comment block as doxygen documentation. All of them are valid - choose what you like best or even mix it. I prefer the format with the @ in this text.
• Mathematical formulas in the documentation via math. LaTeX commands (read, read):
  @f$ v_n = \frac{1}{n^2} \sum_{k=1}^n \frac{6k^2-2k}{n+3}\qquad\forall n=1,\ldots,m  @f$  
  results in
  
  If LaTeX is installed then the appropriate formula can be seen as above. Else the LaTeX-source code is placed into the html. You don't have to install LaTeX if you do not use it otherwise.
• Hyperlinks can be directly included via
  <a href="http://de.wikipedia.org/wiki/Grundumsatz#Harris-Benedict-Formel">Harris-Benedict-Formel</a>
  resulting in the hyperlink Harris-Benedict-Formel, see the source file.
• Variables from the parameter list of a function can be marked in the text via @p followed by the variable name, e.g.,
  we refer to @p m as the last element
• Input/output/inout parameters of a function can be marked in the documentation via
  @param[in]        in_var          This is an input variable.
@param[out]       out_var         This is an output variable.
@param[in,out]    inout_var       This variable is input as well as output.

• Template parameters can be commented as
  @tparam        C STL container
@tparam        T type of container elements
• You can include warnings for the potential user of your function.,
  @warning This function is buggy and will destroy your data.
• cnt ...

G. Haase:  Feb 18, 2021