Graphical front-ends
====================

Python
------
The Python GUI requires ``PyQT4`` to be installed in your system. We recommend
the wonderful Anaconda Python distribution.
Once you have all packages installed, go to ``runPy`` and type

::
    
    python setup.py build_ext --inplace

The code should compile and a dynamic library should be generated, that is
copied to the directory ``pyGUI``.
Go to ``pyGUI`` and type

::
    
    python hazel.py


IDL
---

Although the code can be run in command line by modifying by hand the
input files,  contains also two user friendly front-ends (GUI) for the
simple execution and analysis of the results. Note that the directory
``IDL_routines`` has to be in your IDL path.

.. figure:: images/f5.png
   
   Screen dump of the graphical front-end used for the synthesis.
   
.. figure:: images/inv1.png

   Screen dump of the graphical front-end used for the inversion.
   

.. figure:: images/inv4.png
   
   Screen dump of the graphical front-end used for the inversion.
   

### Synthesis

It is placed in the directory ``Widget_Synth`` and it is invoked with
the following commands:

::

    IDL> .r hazel
    IDL> hazel 

Figure [fig:synthesis\_GUI] shows the GUI for the synthesis mode. All
the parameters explained in the previous sections (fundamentally those
in §[sec:init\_parameters]) are present in the GUI. All the parameters
are very simple to modify (when changing numerical values in the GUI,
always remember to press ``Return`` to activate the change) and clicking
on **Calculate**, the window is updated with the new Stokes profiles.
The GUI also shows the value of the solar radiation field when the
inclination of the line-of-sight and the wavelength of the multiplet is
changed. The value (which can be introduced in the value of :math:`I_0`
as a boundary condition) is given next to the height of the slab and
indicated with the label “Allen”. In case of crashes, the GUI can be
restarted with the following command:

::

    IDL> .r hazel
    IDL> hazel, /reset

### Inversion

It is placed in the directory ``Widget_Inv`` and it is invoked with the
following commands:

::

    IDL> .r hazel_inv
    IDL> hazel_inv

Again, in case of crashes, the GUI can be restarted with the following
command:

::

    IDL> .r hazel_inv
    IDL> hazel_inv, /reset

The GUI for the inversion is more complex because of the large amount of
parameters that have to be changed. For this reason, the GUI is composed
of 4 pages, as indicated in Fig. [fig:inversion\_GUI].

The first page is used to select the output file, together with the
atomic system and multiplet to be used. Finally, the button **Run
inversion** will call  and update the state of the best model in the
plot window.

The second page is used simply to load the file with the observed Stokes
profile. A button is also available to plot the observed data.

The third page controls the behavior of the DIRECT algorithm. It is
essentially a graphical representation of the ``direct_range.dat`` file.

Finally, the fourth page controls the behavior of the cycles, the value
of the fixed parameters, the weights for each Stokes parameter and the
level of physical realism introduced in the simulation.