Approximate Calculation of Sums II: Gaussian Type Quadrature
Approximate Calculation of Sums II: Gaussian Type Quadrature
复制标题
和的近似计算 II:高斯型求积
DOI:
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发表时间:
2016
影响因子:
2.9
通讯作者:
Vanessa G. Paschoa
中科院分区:
文献类型:
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作者:
I. Area;D. Dimitrov;E. Godoy;Vanessa G. Paschoa
The present paper is a continuation of a recent article [SIAM J. Numer. Anal., 52 (2014), pp. 1867--1886], where we proposed an algorithmic approach for approximate calculation of sums of the form $\sum_{j=1}^{N} f(j)$. The method is based on a Gaussian type quadrature formula for sums, which allows the calculation of sums with a very large number of terms $N$ to be reduced to sums with a much smaller number of summands $n$. In this paper we prove that the Weierstrass--Dochev--Durand--Kerner iterative numerical method, with explicitly given initial conditions, converges to the nodes of the quadrature formula. Several methods for computing the nodes of the discrete analogue of the Gaussian quadrature formula are compared. Since, for practical purposes, any approximation of a sum should use only the values of the summands $f({j})$, we implement a simple but efficient procedure to additionally approximate the evaluations at the nodes by local natural splines. Explicit numerical examples are provided. Moreove...