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arXiv 1001.0509math.NAcs.NAphysics.comp-ph
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拉格朗日重构多项式的逼近误差

Approximation error of the Lagrange reconstructing polynomial

Université Pierre-et-Marie-Curie(皮埃尔和玛丽·居里大学)

G. A. Gerolymos

AI总结:

通过引入由递推关系或生成函数定义的有理数τ_n,显式求解了h(x)与f(x)泰勒多项式之间的反卷积问题,并应用于均匀网格上拉格朗日插值多项式重构,显式确定了拉格朗日重构多项式的逼近误差。

摘要:

重构方法[Shu C.W.: {\em SIAM Rev.} {f 51} (2009) 82--126]用于数值逼近$f'(x)$,其基于构造一个对偶函数$h(x)$,使得$h(x)$在区间$[x-\tfrac{1}{2}Δx,x+\tfrac{1}{2}Δx]$上的滑动平均值等于$f(x)$(假设网格单元大小为$Δx$的均匀网格)。我们研究反卷积问题[Harten A., Engquist B., Osher S., Chakravarthy S.R.: {\em J. Comp. Phys.} {f 71} (1987) 231--303],该问题关联$h(x)$和$f(x)$的泰勒多项式,并通过引入由递推关系定义或有理数$τ_n$(其生成函数$g_τ(x)$与${\rm e}^x$的重构对相关)得到其显式解。然后,我们将这些结果应用于基于拉格朗日插值的多项式重构的具体情形,并显式确定了在均匀网格上定义的任意模板上拉格朗日重构多项式(其滑动平均值等于拉格朗日插值多项式)的逼近误差。

英文摘要:

The reconstruction approach [Shu C.W.: {\em SIAM Rev.} {\bf 51} (2009) 82--126] for the numerical approximation of $f'(x)$ is based on the construction of a dual function $h(x)$ whose sliding averages over the interval $[x-\tfrac{1}{2}Δx,x+\tfrac{1}{2}Δx]$ are equal to $f(x)$ (assuming an homogeneous grid of cell-size $Δx$). We study the deconvolution problem [Harten A., Engquist B., Osher S., Chakravarthy S.R.: {\em J. Comp. Phys.} {\bf 71} (1987) 231--303] which relates the Taylor polynomials of $h(x)$ and $f(x)$, and obtain its explicit solution, by introducing rational numbers $τ_n$ defined by a recurrence relation, or determined by their generating function, $g_τ(x)$, related with the reconstruction pair of ${\rm e}^x$. We then apply these results to the specific case of Lagrange-interpolation-based polynomial reconstruction, and determine explicitly the approximation error of the Lagrange reconstructing polynomial (whose sliding averages are equal to the Lagrange interpolating polynomial) on an arbitrary stencil defined on a homogeneous grid.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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