Comparison of the Iterative Methods

Abstract

The basic iterative methods discussed in Chapter C can be classified according to two fundamental features: the type of input for the iterative fitting and the mathematics of the iteration itself. The input is in the form either of energy levels or of line frequencies; for the iteration proper either a “pure least-squares” method is used or the assumption

$$\Delta \lambda = \tilde U \Delta \,H\,U$$

((G.1))

is made (see Eqs. (C.4) and (C.13)). The combination of these features leads to four fundamentally different methods, as illustrated in Table G.1.