Note: The use of the NeXus-API (NAPI) is not mandatory in order to write perfectly valid NeXus files. Using a direct binding to HDF5 (like h5py) or NeXpy should be a better choice for new projects.
The NeXus API is distributed under the terms of the GNU Lesser General Public License.
Since NeXus uses HDF as the main underlying binary format, it is necessary first to install the HDF subroutine libraries and include files before installing the NeXus API. It is not usually necessary to download the HDF source code since precompiled object libraries exist for a variety of operating systems including Windows, Mac OS X, Linux, and various other flavors of Unix. Check the HDF web pages for more information:
The NeXus API also supports using XML as the underlying on-disk format. This uses the Mini-XML library, developed by Michael Sweet, which is also available as a precompiled binary library for several operating systems. Please ensure that you install version 2.2.2 or later. Check the Mini-XML web pages for more information:
The source code distribution can be obtained from GitHub. One can either checkout the git repositories to get access to the most recent development code. To clone the definitions repository use
git clone https://github.com/nexusformat/definitions.git definitions
or for the NAPI
git clone https://github.com/nexusformat/code.git code
For release tarballs go to the release page for the NAPI or the definitions. For the definitions it is recommended to work on the current git repository as the available release is outdated.