The functions described in this chapter accelerate the convergence of a series using the Levin @math{u}-transform. This method takes a small number of terms from the start of a series and uses a systematic approximation to compute an extrapolated value and an estimate of its error. The @math{u}-transform works for both convergent and divergent series, including asymptotic series.
These functions are declared in the header file `gsl_sum.h'.