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In numerical analysis, the Clenshaw algorithm,〔 Note that this paper is written in terms of the ''Shifted'' Chebyshev polynomials of the first kind .〕 also called Clenshaw summation,〔 is a recursive method to evaluate a linear combination of Chebyshev polynomials. It is a generalization of Horner's method for evaluating a linear combination of monomials. It generalizes to more than just Chebyshev polynomials; it applies to any class of functions that can be defined by a three-term recurrence relation. ==Clenshaw algorithm== In full generality, the Clenshaw algorithm computes the weighted sum of a finite series of functions : : where is a sequence of functions that satisfy the linear recurrence relation : where the coefficients and are known in advance. The algorithm is most useful when are functions that are complicated to compute directly, but and are particularly simple. In the most common applications, does not depend on , and is a constant that depends on neither nor . To perform the summation for given series of coefficients , compute the values by the "reverse" recurrence formula: : Note that this computation makes no direct reference to the functions . After computing and , the desired sum can be expressed in terms of them and the simplest functions and : : See Fox and Parker for more information and stability analyses. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Clenshaw algorithm」の詳細全文を読む スポンサード リンク
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