<p>This paper studies function approximation in Gaussian Sobolev spaces over the real line and measures the error in a Gaussian-weighted <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(L^p\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>L</mi> <mi>p</mi> </msup> </math></EquationSource> </InlineEquation>-norm. We construct two linear approximation algorithms using <i>n</i> function evaluations that achieve the optimal or almost optimal rate of worst-case convergence in a Gaussian Sobolev space of order <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\alpha \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>α</mi> </math></EquationSource> </InlineEquation>. The first algorithm is based on scaled trigonometric interpolation and achieves the optimal rate <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(n^{-\alpha }\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>n</mi> <mrow> <mo>-</mo> <mi>α</mi> </mrow> </msup> </math></EquationSource> </InlineEquation> up to a logarithmic factor. This algorithm can be constructed in almost-linear time with the fast Fourier transform. The second algorithm is more complicated, being based on spline smoothing, but attains the optimal rate <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(n^{-\alpha }\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>n</mi> <mrow> <mo>-</mo> <mi>α</mi> </mrow> </msup> </math></EquationSource> </InlineEquation>.</p>

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Construction of optimal algorithms for function approximation in Gaussian Sobolev spaces

  • Yuya Suzuki,
  • Toni Karvonen

摘要

This paper studies function approximation in Gaussian Sobolev spaces over the real line and measures the error in a Gaussian-weighted \(L^p\) L p -norm. We construct two linear approximation algorithms using n function evaluations that achieve the optimal or almost optimal rate of worst-case convergence in a Gaussian Sobolev space of order \(\alpha \) α . The first algorithm is based on scaled trigonometric interpolation and achieves the optimal rate \(n^{-\alpha }\) n - α up to a logarithmic factor. This algorithm can be constructed in almost-linear time with the fast Fourier transform. The second algorithm is more complicated, being based on spline smoothing, but attains the optimal rate \(n^{-\alpha }\) n - α .