The best way to learn about Gammapy is to read and play with the examples in the Gammapy Tutorials.
This section explains the steps to get set up for the Gammapy tutorials on your machine:
Check your setup and Gammapy environment
Use Gammapy with Python, IPython or Jupyter
If you have used conda, Python, IPython and Jupyter before, you can just skim this page, and quickly copy & paste the commands to get set up.
If you have any questions or issues, please ask for help on the Gammapy Slack, mailing list or on Github (whatever is easiest for you, see Gammapy contact)
Check your setup¶
You might want to display some info about Gammapy installed. You can execute the following command, and it should print detailed information about your installation to the terminal:
If there is some issue, the following commands could help you to figure out your setup:
conda info which python which ipython which jupyter which gammapy env | grep PATH python -c 'import gammapy; print(gammapy); print(gammapy.__version__)'
You can also use the following commands to check which conda environment is active and which ones you have set up:
conda info conda env list
If you’re new to conda, you could also print out the conda cheat sheet, which lists the common commands to install packages and work with environments.
Gammapy is a Python package, so you can of course import and use it from Python:
$ python Python 3.6.0 | packaged by conda-forge | (default, Feb 10 2017, 07:08:35) [GCC 4.2.1 Compatible Apple LLVM 7.3.0 (clang-703.0.31)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> from gammapy.stats import CashCountsStatistic >>> CashCountsStatistic(n_on=10, mu_bkg=4.2).significance array([2.39791813])
IPython is nicer to use for interactive analysis:
$ ipython Python 3.6.0 | packaged by conda-forge | (default, Feb 10 2017, 07:08:35) Type 'copyright', 'credits' or 'license' for more information IPython 6.5.0 -- An enhanced Interactive Python. Type '?' for help. In : from gammapy.stats import CashCountsStatistic In : CashCountsStatistic(n_on=10, mu_bkg=4.2).significance Out: array([2.39791813])
For example you can use
? to look up help for any Gammapy function, class or
method from IPython:
In : CashCountsStatistic?
Of course, you can also use the Gammapy online docs if you prefer, clicking in links
gammapy.stats.CashCountsStatistic) or using search docs field in the upper left.
>>> from gammapy.data import DataStore >>> data_store = DataStore.from_dir('$GAMMAPY_DATA/hess-dl3-dr1/') >>> events = data_store.obs(obs_id=23523).events >>> print(events) EventList info: - Number of events: 7613 - Median energy: 0.953 TeV - OBS_ID = 23523 >>> events.energy.mean() <Quantity 4.418008 TeV>
Try to make your first plot using the
gammapy.data.EventList.peek helper method:
>>> events.peek() >>> plt.savefig("events.png")
Another common way to use Gammapy is to write a Python script.
Try it and put the following code into a file called
"""Example Python script using Gammapy""" from gammapy.data import DataStore data_store = DataStore.from_dir('$GAMMAPY_DATA/hess-dl3-dr1/') events = data_store.obs(obs_id=23523).events print(events.energy.mean())
You can run it with Python:
$ python example.py 4.418007850646973 TeV
If you want to continue with interactive data or results analysis after running some Python code, use IPython like this:
$ ipython -i example.py
For examples how to run Gammapy analyses from Python scripts, see Scripts.
To learn more about Gammapy, and also for interactive data analysis in general, we recommend you use Jupyter notebooks. Assuming you have followed the steps above to install Gammapy and activate the conda environment, you can start JupyterLab like this:
$ jupyter lab
This should open up JupyterLab app in your web browser, where you can
create new Jupyter notebooks or open up existing ones. If you have downloaded the
gammapy download tutorials, you can browse your
folder with Jupyterlab and execute them there.
If you haven’t used Jupyter before, try typing
print("Hello Jupyter") in the
first input cell, and use the keyboard shortcut
SHIFT + ENTER to execute it.
If you have problems and think you might not be using the right Python or importing Gammapy isn’t working or giving you the right version, checking your Python executable and import path might help you find the issue:
import sys print(sys.executable) print(sys.path)
To check which Gammapy you are using you can use this:
import gammapy print(gammapy) print(gammapy.__version__)
Now you should be all set and to use Gammapy. Let’s move on to the Tutorials.