Quickstart

Flux diagram summarising the main steps required to run GalaPy.

Tip

Click (or tap) on the filled boxes in the flux diagram above to be re-directed to the relative documentation page with in-detail explanation of the step.

The GalaPy workflow can be summarised in two blocks of steps, the first one (dubbed “GalaPy library set-up”) has to be performed only once:

Install the library through pip:
```
$ pip install galapy-fit
```
Download the database through the dedicated terminal command:
```
$ galapy-download-database
```
Note that the official GalaPy database occupies approximately 300 MB and will take tens of seconds up to few minutes to download (depending on internet connection).

This is enough to have a working installation of GalaPy.

In order to fit a photometric dataset the steps to follow are the ones detailed in the “GalaPy” workflow block above:

Generate the parameter file and modify it accordingly to the requirements of your dataset. As a term of comparison, to generate a parameter file to fit panchromatic data with an In-Situ SFH model, call the command
```
$ galapy-genparams --name insitu_params --SFH_model insitu
```
which will generate a file called insitu_params.py.

By opening this text file change the entries for the following parameters
```
bands  = None
fluxes = None
errors = None
```
with the values of your observed source (see Import the observational data for more details).

Note

Fluxes have to be given in $mJy$ (milli-Jansky), see Physical Units (used in functions Input/Output) for further details on the physical units assumed in the library.

Tip

A complete list of the bands available in the database is print on screen by calling function galapy.PhotometricSystem.print_filters().

Another section that it could be useful to adapt to the user’s requirements is the Sampling and output format choices section of the parameter file, where the sampler and run specifications are chosen.
Run the fitting algorithm by calling the terminal command, using the parameter file generated at the previous step:
```
$ galapy-fit insitu_params.py
```
This will start the fitting procedure that will take (depending on the statistical properties of the sample, installation and system) from a bunch of minutes to several tens of minutes. When the program finishes its run, a file (or several files) with extension .galapy.hdf5 is generated in the location specified in the parameter file (if no choice is made it will be saved in the working directory).
Analyse the dataset by following the tutorial in Results analysis

For further details on each of these steps, please follow the links in the filled boxes of the flux diagram at the beginning of this page and in the following text.