释义 |
Convergence ImprovementThe improvement of the convergence properties of a Series, also called Convergence Acceleration, suchthat a Series reaches its limit to within some accuracy with fewer terms than required before.Convergence improvement can be effected by forming a linear combination with a Series whose sum isknown. Useful sums include
Kummer's transformation takes a convergent series
 | (5) |
and another convergent series
 | (6) |
with known such that
 | (7) |
Then a series with more rapid convergence to the same value is given by
 | (8) |
(Abramowitz and Stegun 1972).
Euler's Transform takes a convergent alternating series
 | (9) |
into a series with more rapid convergence to the same value to
 | (10) |
where
 | (11) |
(Abramowitz and Stegun 1972; Beeler et al. 1972, Item 120).
Given a series of the form
 | (12) |
where is an Analytic at 0 and on the closed unit Disk, and
 | (13) |
then the series can be rearranged to
where
 | (15) |
is the Maclaurin Series of and is the Riemann Zeta Function (Flajolet and Vardi 1996). Thetransformed series exhibits geometric convergence. Similarly, if is Analyticin for some Positive Integer , then
 | (16) |
which converges geometrically (Flajolet and Vardi 1996). (16) can also be used to further accelerate the convergence ofseries (14).See also Euler's Transform, Wilf-Zeilberger Pair References
Abramowitz, M. and Stegun, C. A. (Eds.). Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, 9th printing. New York: Dover, p. 16, 1972.Arfken, G. Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, pp. 288-289, 1985. Beeler, M.; Gosper, R. W.; and Schroeppel, R. HAKMEM. Cambridge, MA: MIT Artificial Intelligence Laboratory, Memo AIM-239, Feb. 1972. Flajolet, P. and Vardi, I. ``Zeta Function Expansions of Classical Constants.'' Unpublished manuscript. 1996. http://pauillac.inria.fr/algo/flajolet/Publications/landau.ps.
|