Toolbox for the analysis of astronomical gamma-ray data –

GammaLib information

  • Version: (23 June 2022)

Build Status

Quality Gate

License information

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see

What's new in this release?

See the files NEWS and ChangeLog.

What is the GammaLib anyway?

The GammaLib is a versatile toolbox for the high-level analysis of astronomical gamma-ray data. It is implemented as a C++ library that is fully scriptable in the Python scripting language. The library provides core functionalities such as data input and output, interfaces for parameter specifications, and a reporting and logging interface. It implements instruments specific functionalities such as instrument response functions and data formats. Instrument specific functionalities share a common interface to allow for extension of the GammaLib to include new gamma-ray instruments. The GammaLib provides an abstract data analysis framework that enables simultaneous multi-mission analysis.

Web sites


GammaLib should compile on every modern Unix system without any need to install other libraries.

To enable support for FITS file handling, however, the cfitsio library from HEASARC needs to be installed. cfitsio can be downloaded from and detailed installation instructions can be found there. If cfitsio does not already exist on your system, we recommend installation of cfitsio in the default GammaLib install directory as a shared library by typing:

 $ ./configure --prefix=/usr/local/gamma
 $ make shared
 $ make install

GammaLib can also benefit from the presence of the readline library that provides line-editing and history capabilities for text input (GammaLib offers however also full functionality without having readline installed). readline requires the ncurses library. Both libraries can be downloaded from

Conda Installation

The easiest is to install GammaLib via conda. This also takes care of the installation of cfitsio. Assuming that you have installed anaconda, type the following:

 $ conda config --append channels conda-forge
 $ conda config --append channels cta-observatory
 $ conda install gammalib

Linux Installation

To build, verify and install GammaLib, simply type the following:

 $ ./configure
 $ make
 $ make check
 $ make install

If the folder does not contain any configure file, please run

 $ ./ 

before invoking configure.

By default GammaLib installs itself in /usr/local/gamma. If you need to install GammaLib in a different location or in your home directory, use the --prefix option to ./configure. For example:

 $ ./configure --prefix=/home/yourname/projects
 $ make
 $ make check
 $ make install

The file INSTALL details more about using configure. Also try

 $ ./configure --help.

The make check command will run an extensive unit test to verify that GammaLib was correctly built. Make sure that all tests were successful.

Macintosh OS Installation

GammaLib is known to work on various flavors of Mac OS. To cope with different system versions and architectures, there are two Mac specific configure options:

 $ ./configure --enable-universalsdk[=PATH]

creates a universal build of GammaLib. The optional argument specifies which MacOS SDK should be used to perform the build. This defaults to /Developer/SDKs/MacOSX.10.4u.sdk. Specify / when building on a 10.5 system or higher, especially when building 64-bit code.

 $ ./configure --with-univeral-archs=VALUE

specifies the kind of universal build that should be created. Possible values are: 32-bit, 3-way, intel or all. By default, a 32-bit build will be made. This option is only valid when --enable-universalsdk is specified.

These options are in particular needed if your Python architecture differs from the default architecture of your system. To examine the Python architecture you may type:

 $ file `which python`

which will return the architectures that are compiled in the Mach-0 executable:

 i386    32-bit intel
 ppc     32-bit powerpc
 ppc64   64-bit powerpc
 x86_64  64-bit intel

If Python is 32-bit (ppc, i386) but the compiler produces by default 64-bit code (ppc64, x86_64), the Python module will not work. Using

 $ ./configure --enable-universalsdk=/

will force a universal 32-bit build which creates code for ppc and i386. If on the other hand Python is 64-bit (ppc64, x86_64) but the compiler produces by default 32-bit code (ppc, i386), the option

 $ ./configure --enable-universalsdk=/ --with-univeral-archs=3-way

will generate a universal build which contains 32-bit and 64-bit code.

BSD Installation

GammaLib has been tested on FreeBSD successfully. Follow the Linux installation instructions above.

Solaris Installation

GammaLib compiles on Solaris and openSolaris using the GNU compiler collection. Follow the Linux installation instructions above. GammaLib also compiles using the Sun Studio compiler, but due to some unexpected handling of global variables, it is not fully working (see "Known problems" below). Please note that these is also a cfitsio problem on Solaris, please refer to the section "Known problems" for more information.

Windows Installation

On Windows GammaLib needs to be installed into a virtual machine running a Linux distribution.


After building and before installing GammaLib, you should run the extensive unit test by typing:

$ make check

If everything works successfully you should see

All 22 tests passed


Testsuite summary for gammalib
# TOTAL: 22
# PASS:  22
# SKIP:  0
# XFAIL: 0
# FAIL:  0
# XPASS: 0
# ERROR: 0

at the end of the test (depending on your automake version). If no Python support was compiled in, the number of tests performed will be reduced by one.

Setting up your environment

Before using GammaLib you have to setup some environment variables. This will be done automatically by an initialisation script that will be installed in the bin directory.

Assuming that you have installed GammaLib in the default directory /usr/local/gamma you need to add the following to your $HOME/.bashrc or $HOME/.profile script on a Linux machine:

export GAMMALIB=/usr/local/gamma
source $GAMMALIB/bin/

If you use C shell or a variant then add the following to your $HOME/.cshrc or $HOME/.tcshrc script:

setenv GAMMALIB /usr/local/gamma
source $GAMMALIB/bin/gammalib-init.csh

Getting started

The easiest way to start with GammaLib is by using the python interface. To start, type the following:

$ python
>>> import gammalib
>>> models=gammalib.GModels()
>>> print models
=== GModels ===
Number of models ..........: 0
Number of parameters ......: 0

This examples allocates an empty GModels object that holds a collection of models.

For examples, inspect the test directory, and the test directories of the instrument specific interfaces, e.g. inst/mwl/test, inst/lat/test, and inst/cat/test.


The doc directory (usually at /usr/local/gamma/share/doc/gammalib) contains the most recent set of updated documentation for this release. A detailed documentation can be created by typing:

$ make doc

before installing the library. Two types of documentation exist:

  • code documentation
  • user documentation

Code documentation is created using Doxygen. You need Doxygen on your system to generate the code documentation. This includes man pages. Doxygen can be obtained from

User documentation is created using Sphinx. You need Sphinx on your system to generate the user documentation. Sphinx can be obtained from

Bug reports

To report or search for bugs, please use the GammaLib Bug Tracker at Before using the tracker, please read

Known problems

Python support

GammaLib comes with Python wrappers so that all classes can be directly used from Python. To compile-in Python support, GammaLib needs the Python.h header file, which on many distributions is not installed by default. To make Python.h available, install the Python developer package in your distribution. Otherwise you will not be able to use GammaLib from Python.

Readline support

Many distributions do not have the readline header files and symbolic link to the shared library set up by default. The same is true for the ncurses library that is needed by readline. To properly compile-in readline support in GammaLib, make sure that the redline header files exist and that the symbolic links are set. In many distributions, the shared redline and ncurses are located in /lib, while the symbolic links are in /usr/lib. Make sure that you have symbolic links with names

Symbolic links with an additional number attached, such as or (which are found in many distributions in the /lib directory) are not sufficient. In many distributions, the appropriate headers and symbolic links are installed if the proper readline and ncurses developer packages are installed.


Although GammaLib builds on Solaris using the Sun compiler, there are problems with global symbols in the shared library that prevent the model registry to work correctly. Furthermore, GammaLib is not able to catch its own exceptions, which prevents the FITS interface to work correctly. GammaLib has however been built and tested successfully using the GNU compiler, and this is the only build method that is currently supported. Problems have also been encountered when compiling cfitsio versions more recent than 3.250. The problems have been reported to the cfitsio developer team, and are likely to be solved in the future. For the time being, it is recommended to use cfitsio version 3.250 on Solaris.


On OpenSolaris, the same problems concerning the SunStudio compiler occur as for Solaris, and also here, the GNU compiler is the recommended tool to build GammaLib. Also here, cfitsio version 3.250 is the recommended library as more recent version feature relocation problems. GammaLib has been tested using gcc 4.3.2 on OpenSolaris 2009.06. Make sure to create the symbolic links

 ln -s /usr/bin/gcc4.3.2 /usr/bin/gcc
 ln -s /usr/bin/g++4.3.2 /usr/bin/g++

which are not there by default to avoid excess warnings during compilation. For OpenSolaris 2009.06, no readline package is available, hence readline support is not readily available. Readline support can however be enabled by directly installing the GNU ncurses and readline packages from source ( This has been done successfully on OpenSolaris 2009.06 for ncurses-5.9 and readline-6.2. Make sure to specify the --with-shared option when configuring ncurses, so that the shared library will be built and installed. Otherwise, relocation errors may occur during compilation of GammaLib.


To get in touch with the GammaLib developers and to contribute to the project please contact Juergen Knoedlseder