Consortium of Swiss Academic Libraries

Linear barycentric rational quadrature

Klein, Georges ; Berrut, Jean-Paul

In: BIT Numerical Mathematics, 2012, vol. 52, no. 2, p. 407-424

Université de Fribourg

Recent advances in linear barycentric rational interpolation

Berrut, Jean-Paul ; Klein, Georges

In: Journal of Computational and Applied Mathematics, 2014, vol. 259, Part A, p. 95–107

Well-conditioned, stable and infinitely smooth interpolation in arbitrary nodes is by no means a trivial task, even in the univariate setting considered here; already the most important case, equispaced points, is not obvious. Certain approaches have nevertheless experienced significant developments in the last decades. In this paper we review one of them, linear barycentric rational...

Université de Fribourg

The linear barycentric rational quadrature method for Volterra integral equations

Berrut, Jean-Paul ; Hosseini, S. A. ; Klein, Georges

In: SIAM Journal on Scientific Computing, 2014, vol. 36, no. 1, p. A105–A123

We introduce two direct quadrature methods based on linear rational interpolation for solving general Volterra integral equations of the second kind. The first, deduced by a direct application of linear barycentric rational quadrature given in former work, is shown to converge at the same rate as the rational quadrature rule but is costly on long integration intervals. The second, based on a...

Université de Fribourg

Applications of linear barycentric rational interpolation

Klein, Georges ; Berrut, Jean-Paul (Dir.)

Thèse de doctorat : Université de Fribourg, 2012 ; no. 1762.

This thesis is a collection of properties and applications of linear barycentric rational interpolation, mainly with the weights presented by Floater and Hormann in 2007. We are motivated by the counterintuitive and provable impossibility of constructing from equispaced data an approximation scheme that converges very rapidly to the approximated function and is simultaneously computationally...

Université de Fribourg

An extension of the Floater–Hormann family of barycentric rational interpolants

Klein, Georges

In: Mathematics of Computation, 2012, vol. 82, no. 284, p. 2273-2292

The barycentric rational interpolants introduced by Floater and Hormann in 2007 are “blends” of polynomial interpolants of fixed degree d. In some cases these ratio- nal functions achieve approximation of much higher quality than the classical poly- nomial interpolants, which, e.g., are ill-conditioned and lead to Runge’s phenomenon if the interpolation nodes are equispaced. For such...

Université de Fribourg

Convergence of linear barycentric rational interpolation for analytic functions

Güttel, Stefan ; Klein, Georges

In: SIAM Journal on Numerical Analysis, 2012, vol. 50, no. 5, p. 2560–2580

Polynomial interpolation to analytic functions can be very accurate, depending on the distribution of the interpolation nodes. However, in equispaced nodes and the like, besides being badly conditioned, these interpolants fail to converge even in exact arithmetic in some cases. Linear barycentric rational interpolation with the weights presented by Floater and Hormann can be viewed as blended...

Université de Fribourg

Linear rational finite differences from derivatives of barycentric rational interpolants

Klein, Georges ; Berrut, Jean-Paul

In: SIAM Journal on Numerical Analysis, 2012, vol. 50, no. 2, p. 643–656

Derivatives of polynomial interpolants lead in a natural way to approximations of derivatives of the interpolated function, e.g., through finite differences. We extend a study of the approximation of derivatives of linear barycentric rational interpolants and present improved finite difference formulas arising from these interpolants. The formulas contain the classical finite differences as a...

Université de Fribourg

Linear barycentric rational quadrature

Klein, Georges ; Berrut, Jean-Paul

In: Bit Numerical Mathematics, 2012, vol. 52, no. 2, p. 407-424

Linear interpolation schemes very naturally lead to quadrature rules. Introduced in the eighties, linear barycentric rational interpolation has recently experienced a boost with the presentation of new weights by Floater and Hormann. The corresponding interpolants converge in principle with arbitrary high order of precision. In the present paper we employ them to construct two linear rational...

Université de Fribourg

Barycentric rational interpolation at quasi-equidistant nodes

Hormann, Kai ; Klein, Georges ; De Marchi, Stefano

In: Dolomites Research Notes on Approximation, 2012, vol. 5, no. 1, p. 1-6

A collection of recent papers reveals that linear barycentric rational interpolation with the weights suggested by Floater and Hormann is a good choice for approximating smooth functions, especially when the interpolation nodes are equidistant. In the latter setting, the Lebesgue constant of this rational interpolation process is known to grow only logarithmically with the number of nodes....

Université de Fribourg

On the Lebesgue constant of barycentric rational interpolation at equidistant nodes

Bos, Len ; De Marchi, Stefano ; Hormann, Kai ; Klein, Georges

In: Numerische Mathematik, 2012, vol. 121, p. 461–471

Recent results reveal that the family of barycentric rational interpolants introduced by Floater and Hormann is very well-suited for the approximation of functions as well as their derivatives, integrals and primitives. Especially in the case of equidistant interpolation nodes, these infinitely smooth interpolants offer a much better choice than their polynomial analogue. A natural and important...