Global Arrays, or GA, is the library developed by scientists at Pacific Northwest National Laboratory for parallel computing.
The GA library is a predecessor to the GAS (global address space) languages currently being developed for high-performance computing.
GA includes simple matrix computations (matrix-matrix multiplication, LU solve) and works with ScaLAPACK.
GA was developed by Jarek Nieplocha, Robert Harrison, R. J. Littlefield, Manoj Krishnan, and Vinod Tipparaju.
The GA library is incorporated into many quantum chemistry packages, including NWChem, MOLPRO, UTChem, MOLCAS, and TURBOMOLE.