{ "id": "1001.0509", "version": "v3", "published": "2010-01-04T13:31:16.000Z", "updated": "2010-10-05T17:14:45.000Z", "title": "Approximation error of the Lagrange reconstructing polynomial", "authors": [ "G. A. Gerolymos" ], "comment": "31 pages, 1 table; revised version to appear in J. Approx. Theory", "journal": "J. Approx. Theory 163 (2011) 267-305", "doi": "10.1016/j.jat.2010.09.007", "categories": [ "math.NA", "physics.comp-ph" ], "abstract": "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 $[x-\\tfrac{1}{2}\\Delta x,x+\\tfrac{1}{2}\\Delta x]$ are equal to $f(x)$ (assuming an homogeneous grid of cell-size $\\Delta x$). 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 $\\tau_n$ defined by a recurrence relation, or determined by their generating function, $g_\\tau(x)$, 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.", "revisions": [ { "version": "v3", "updated": "2010-10-05T17:14:45.000Z" } ], "analyses": { "subjects": [ "65D99", "65D05", "65D25", "65M06", "65M08" ], "keywords": [ "lagrange reconstructing polynomial", "approximation error", "homogeneous grid", "sliding averages", "introducing rational numbers" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 31, "language": "en", "license": "arXiv", "status": "editable" } } }