By default, MULTI uses the non-linear optimization method developed by Werner, Meyer, and
Knowles. Other methods, such as the Newton-Raphson procedure or the Augmented Hessian procedure,
are also implemented and can be selected using the ITERATIONS directive (for state-averaged
calculations, only the non-linear optimization method can be used). For CASSCF
calculations, the CI problem is solved in a basis of Slater determinants, unless a CONFIG card is given. Some procedures may be disabled using the DONT directive.
19.6 Selecting the optimization methods