There are two possible ways to obtain the ELPA library:
a) tar-ball archive:
If you want to use the ELPA library and not contribute to it, the easiest way is to download an officially released tar-packages, which you can find here.
However, the latest changes and the various development versions (e.g. GPU support) are not released and are not distributed via tar-archives.
b) Access to the git repository:
If you want to contribute to the ELPA library (e.g. put your improvements or port to other architectures (and so forth) in the official ELPA version) the access to the git server is the best way to go.
Also, in the git repository you can find various development branches, recent changes, etc., which have not yet been officially released and been bundled into tar-archives.
To obtain access to the ELPA git repository, please go to http://elpa-lib.fhi-berlin.mpg.de/. Use the "git access registration" link at the top of http://elpa-lib.fhi-berlin.mpg.de/ to register for access to the git server.
Licencing of ELPA:
The license for ELPA is the LGPL . That said, for the time being we kindly ask you to cite the original ELPA library in your work whenever it is useful, and that you actively contribute back any amendments / improvements that you may have.
To cite ELPA, please use the following references:
T. Auckenthaler, V. Blum, H.-J. Bungartz, T. Huckle, R. Johanni, L. Krämer, B. Lang, H. Lederer, and P. R. Willems: "Parallel solution of partial symmetric eigenvalue problems from electronic structure calculations" Parallel Computing 37, 783-794 (2011). A preprint (pdf) can be found here.
A. Marek, V. Blum, R. Johanni, V. Havu, B. Lang, T. Auckenthaler, A. Heinecke, H.-J. Bungartz, and H. Lederer: "The ELPA library - Scalable parallel Eigenvalue Solutions for Electronic Structure Theory and Computational Science" psi-k.org, Scientific Highlight for December (2013). A preprint (pdf) can be found here.
If you run into problems using the ELPA library, we recommend the following steps:
1.) Have a look at the ELPA or at the ELPA forum. This is the right place to post and exchange experiences.
2.) In the ELPA library software, we provide an additional email address to contact the developers of the ELPA library.