Level 1, Level 2, and Level 3 packages can be built independently of the applications and used in your own codes if you wish. However, please heed this warning:
Given the number of modules and the combinatorically larger variety of possible ways to combine them, we suggest that if you are new to this game you can save yourself a lot of frustration by checking out one of the application suites above.

Having said all that, the currently available Level 1 SciDAC modules are described and listed below:

QLA	Maintainer: James Osborn (osborn[at]alcf[dot]anl[dot]gov) Source code:  tar-ball   repository Web site:  https://github.com/usqcd-software/qla Reference to cite:

QLA provides a standard interface for linear algebra routines that can act on a site or a array of sites with several indexing options. This implementation provides a complete library of all the functions in the QLA name space and includes some code that has been optimized to attain very high performance on some architectures.

QMP	Maintainer: James Osborn (osborn[at]alcf[dot]anl[dot]gov) Source code:  tar-ball   repository Web site:  https://github.com/usqcd-software/qmp Reference to cite:

QMP provides a standard communications layer for Lattice QCD. The communications primitives provided are leaner than say MPI and are suitable for very efficient implementation on a variety of interconnects. By using QMP you can abstract away your  parallel interconnect. 

QMT	Maintainer: Jie Chen (chen[at]jlab[dot]org) Source code:  tar-ball   repository Web site:  https://github.com/usqcd-software/qmt/ Reference to cite:

QMT is a software library providing OpenMP like fork-join multi-thread APIs. The current implementation works on i386 and x86-64 using pthread and other optimizations.