The Einstein@Home source code is released under the GNU General Public License, version 2.
The source code can be obtained from the LALSuite git repository of the LSC Data Analysis Software Working Group. It's a HierarchSearchGCT program from the sources in lalapps/src/pulsar/GCT of the LALSuite tree.
A script that downloads / checkouts all necessary source code from different archives and compiles it into an Einstein@Home App is maintained in the LALSuite tree, in lalapps/src/pulsar/hough/src2/EinsteinAtHome/eah_build2.sh. Building an Einstein@Home App running this should work right away on most UNIX-style systems that have git, svn and curl installed, as well as the BOINC prerequisites (libjpeg, libcurl, openssl). The script should build both an eah_HierarchicalSearch App (that was used for runs S5R2 - S5R6) and an eah_HierarchSearchGCT App as currently in use.
Applications for MS Windows can be cross-compiled on a Linux system unsing eah_build2.sh with option --win32. This requires a MinGW-gcc being installed in the PATH.
The source code can be obtained by downloading the following archive: latest release
You can use the script build.sh to build native binaries for Windows (cross-compiled on Linux using MinGW!), Mac OS X and Linux. This script will download all 3rd-party libraries and build them before building the actual science application. The script will check whether all prerequisites are met and supports checkpointing. For CUDA or OpenCL builds, please make sure PATH as well as CUDA_INSTALL_PATH or AMDAPPSDKROOT respectively are set properly.
Please understand that at the time of writing we don't have the capacity to grant any further support for building your own Apps (we still might, though, if kindly asked and if we have the time). We also don't guarantee that a build will succeed on any particular system at any given time.
If you build your own Apps, you could run them on "anonymous platform" (see BOINC documentation), but we kindly ask you to use version numbers not larger than 100 ("1.00"), so that they don't conflict withe ones in use by official Apps of the project at any time.
If you improve the code or modify it in any way (e.g. to compile on a certain platform), please provide feedback and tell us what you did, either in the Einstein@Home forums or by writing to a project developer personally.