Graphical unitary group approach (GUGA) is a technique used to construct Configuration state functions (CSFs) in computational quantum chemistry.
The foundation of the unitary group approach (UGA) can be traced to the work of Moshinsky.
[1] Later, Shavitt[2][3] introduced the graphical aspect (GUGA) drawing on the earlier work of Paldus.
[5][6] offering certain performance advantages over the older, sometimes called traditional, techniques for CSF construction.
However traditional methods can offer other advantages[7] such as the ability to handle degenerate symmetry point groups, such as