.. _p3d_simul:

Simulations with pyFIT3D
========================

.. contents::

.. _p3d_simul_present:

Presentation
------------

We have created two simple simulations using **pyFIT3D** `module <modules.html>`_. Both examples are coded using the classic notebook interface `Jupyter Notebook <https://jupyter.org/>`_, which is very easy to edit, modify and run.

.. _p3d_simul_eml:

Emission Lines simulations
--------------------------

This simulation creates a :math:`{\rm [NII]+H}\alpha` model spectrum, adds noise and fit it with the function `fit_elines_main() <pyFIT3D.common.html#pyFIT3D.common.gas_tools.fit_elines_main>`_. At the end, all simulation output (properties and spectra) is stored in FITS files.

* `Download here the Emission Lines simulation notebook. <notebooks/eml/simulation_EmissionLines_NIIHa.ipynb>`_

.. _p3d_simul_ssp:

Stellar population analysis simulation
--------------------------------------

**NOTE:** This example requires `Pandas <https://pandas.pydata.org/>`_ (*pip install pandas*).

This example uses a SSP library (see :ref:`pipeline_readme_ssplibfits`) and a *file* with the coefficients (*weights*) of each *SSP model* inside the library, in order to to create a known age-metallicity representative spectrum. Kinematics and dust extinction effects applyied. After this, the spectrum is analyzed using the function `auto_ssp_spec() <pyFIT3D.common.html#pyFIT3D.common.auto_ssp_tools.auto_ssp_spec>`_.

* `Download here the Stellar population analysis simulation notebook. <notebooks/ssp/>`_

Needed files
''''''''''''

In addition to the files needed to the stellar population analysis (see :ref:`auto_ssp_config_file`), this example need some auxiliary files.

1. Input real parameters file (*used in this example: real_parameters.csv*)
2. Foreach line in real pars file, a file with the coeffs for the spectrum creation is needed.
3. SSP libraries (*used in this example: gsd01_12.fits and gsd01_156.fits*)

Files formats
'''''''''''''

**Input real parameters file:** Each line of the file represents one input spectrum for the simulation. The line should be composed of the non-linear parameters (redshift, velocity dispersion and A_V, the dust extinction parameter). Example of parameters file::

  redshift,Av,LOSVD
  0.03186,0.23318,314.72231
  0.02176,0.42848,193.17778

**Coefficients filenames** for the parameters file above::

  coeffs_input.losvd314p7223-av0p2332-redshift0p0319.txt
  coeffs_input.losvd193p1778-av0p4285-redshift0p0218.txt

I.e., the value of the parameters formatted with 4 decimals and the '.' replaced to 'p'.

Each **coefficient file** should carry the ID, AGE, MET and the COEFF::

  #ID MET AGE COEFF
  0.000 3.7047000e-03 1.0000021e-03 5.7196858e-03
  1.000 7.5640000e-03 1.0000021e-03 1.0281415e-02
  2.000 1.8999999e-02 1.0000021e-03 5.3646386e-03
  (...)

For this particular example we use the *SSP library* **gsd01_156.fits** to generate the spectrum and the same library to fit it. The compact version of this library (**gsd01_12.fits**) is used to the non-linear fit. We also leave a *2000 examples* of coefficients files and a *real_parameters.csv* file containing all of them.

.. README created by:
.. Eduardo Alberto Duarte Lacerda
.. mailto: dhubax@gmail.com