Please follow these instructions when commenting your code for the Doxygen class documentation.
When checking doxygen, the doxygen should be built and the doxyerr.log should have as little lines/errors as possible.
The Doxygen for a **file** should look like this:
```
/*!
* \file
* \ingroup Common
* \brief Manages the handling of time dependent problems
*/
```
It should always contain the `\file` first.
The `\ingroup` gives a Group that is as **precise** as possible and is part of the `modules.txt`
The `\brief` is a **short comment** on what happens in the file. Alternatively a `\copybrief` could be used. **Make sure the copybrief links to the correct section and is not ambigous!**
Additional text could be added similar to the function description.
A class could look like this:
```
/*!
* \ingroup Common
* \brief Manages the handling of time dependent problems.
*
* This class facilitates the time management of the simulation.
* It doesn't manage [...]
* [...]
* [...] index starting at 0.
*
* \note Time and time step sizes are in units of seconds
*/
```
The class should always have the proper `\ingroup` just like the file.
The `\brief` should always contain a **short description**, and only in very very rare occasions a class can have a `\copybrief`. In the end this is also documentation for users that do not build doxygen and `\copybriefs` from another file are most likely not very useful.
The main part should be an in depth explanation of what is done. This should contain math-expressions where applicable. They can look like the following:
```
* This class implements a spline \f$s(x)\f$ for which, given \f$n\f$ sampling
* points \f$x_1, \dots, x_n\f$, the following conditions hold
*\f{align*}{
s(x_i) & = y_i \quad \forall i \in \{1, \dots, n \}\\
s'(x_1) & = m_1 \\
s'(x_n) & = m_n
\f}
*
```
For a **function** in a file the Doxygen can look like this:
```
/*!
* \brief Set the current simulated time and the time step index.
*
* \param t The time \f$\mathrm{[s]}\f$ which should be jumped to
* \param stepIdx The new time step index
*/
void setTime(Scalar t, int stepIdx)
{ time_ = t; timeStepIdx_ = stepIdx; }
```
The function has a **short comment** with the `\brief`.
If there are **function-arguments** that are not self-explanatory, they should be described using `\param`.
**Always explain all params or no params at all!** Otherwise Doxygen will throw an error.
Template parameters are documented with `\tparam`.
Additional Doxygen-commands that might be useful are `\note` for giving an important note/hint on what the function does as well as `\return` which specifies the return value (if applicable).
