The influence of the shift parameter β upon the convergence of the u-transformation may be crucial. It is shown, through a specific example, that a clever choice of β can improve the convergence acceleration rate of the u-transformation, while a wrong choice may even imply divergence of the method. A constructive approach for choosing an optimal shift parameter β is presented, based upon the exactness class (model) of the u-transformation. The parameter β which defines the best fitted model to a specific sequence is chosen for the acceleration of that sequence.
- Nonlinear sequence transformations
- Parameter optimization
- u- transformation