.. _gui-short:

XCLASS-GUI
==========

.. figure:: ../figures/GUI_Tab1.png
   :align: center
   :width: 100%
   :name: fig-gui-tab1a

   XCLASS-GUI, Tab: Files.

The ``XCLASS-GUI`` can be started at the command line with

::

       XCLASS-GUI --molfit=. --alg=. --obs=.

where the command line arguments ``molfit``
(Sect. ":ref:`myxclass-molfit`"), ``alg``
(Sect. ":ref:`myxclassfit-alg-xml-file`"), and ``obs``
(Sect. ":ref:`myxclassfit-obs-xml-file`") are optional and define the path
and name of a molfit, algorithm xml, and obs. xml file, respectively.


.. figure:: ../figures/GUI_Range-Selection.png
   :align: center
   :width: 100%
   :name: fig-gui-tab1b

   XCLASS-GUI, Tab: Select Range.


.. figure:: ../figures/GUI_Algorithm-GUI.png
   :align: center
   :width: 50%
   :name: fig-gui-tab1c

   XCLASS-GUI, Tab: Optimization algorithms.


The graphical user interface (GUI) included in the extended *XCLASS*
package offers the possibility to interactively model observational data
and to describe molecules and recombination lines in LTE. It can be
used to describe molecular emission and generate synthetic spectra from
input physical parameters. These synthetic spectra can be overlaid on
the observed spectra and/or fitted to the observations to obtain the
best fit to the physical parameters.

The GUI consists of three tabs, where the first tab, see
:numref:`fig-gui-tab1a`, specifies, among other
things, which ranges of the observation data are to be fitted. Here, the
definition of the different fitting ranges can be done interactively,
see :numref:`fig-gui-tab1b`, together with the
specification of the corresponding continuum level according to
Eq. :eq:`PhenContFunc3`. Additionally, a user friendly
GUI interface, see :numref:`fig-gui-tab1c`, provides
the opportunity to select and control an optimization algorithm used for
fitting. Here, different optimization algorithms can be combined to
utilize the advantages of different algorithms.

The second tab, see :numref:`fig-gui-tab2`, allows the
user to model the contribution of a particular molecule, assessing the
effects of changing the input parameters in real time. Here, the
synthetic spectra are shown together with the observational data around
selected transitions of a certain molecule. Additionally, the molecular
parameters for each transitions are displayed as well. Other transitions
are available via the arrow buttons. The different transitions can be
ordered in four different ways: In ascending order by the energy of the
lower state :math:`(E_{\rm low})`, by descending order of the transition
strength, i.e. by the product of Einstein A coefficient and upper state
degeneracy :math:`(g \cdot A)`, by a weighting factor :math:`w_j`
defined as

.. math:: w_j = \frac{g_j \, A_j}{E_{{\rm low}, j}^2},

where :math:`g_j`, :math:`A_j` and :math:`E_{{\rm low}, j}` represents
the upper state degeneracy, the Einstein A coefficient, and the energy
of the lower state of a transition :math:`j`, respectively, and by the
transition frequency. In addition to that the user can declare a lower
limit for the transition strength, an upper limit for the lower energy,
and for the total number of transitions. In the bottom half of the GUI,
the LTE parameters for a certain molecule and component are shown. Here,
the user can define ranges for each parameter and component, add or
remove components, and activate or deactivate the contribution of a
certain component to the synthetic spectra to estimate the contribution
of a certain component. Finally, the physical parameters for the current
molecule can be fitted directly to the observational data using the
optimization algorithm(s) defined in the previous tab. Here, individual
parameters can be fixed as well.


.. figure:: ../figures/GUI_Tab2.png
   :align: center
   :width: 100%
   :name: fig-gui-tab2

   XCLASS-GUI, Tab: "Single-Molecule-Fits"


Finally, the third tab, see :numref:`fig-gui-tab3`,
displays the synthetic spectra including the contributions of all
molecules together with the observational data. Additionally, the
parameters for each molecule and component are shown as well. Moreover,
the GUI offers the possibility to fit all parameters of all components
simultaneously to take line blending effects into account.


.. figure:: ../figures/GUI_Tab3.png
   :align: center
   :width: 100%
   :name: fig-gui-tab3

   XCLASS-GUI, Tab: "Fit-All".



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