NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Shape-Preserving, Multi-Scale Fitting of Bivariate Data by Cubic L1 Smoothing Splines
Published
Author(s)
David E. Gilsinn, J E. Lavery
Abstract
Bivariate cubic L1 smoothing splines are introduced. The coefficients of a cubic L1 smoothing spline are calculated by minimizing the weighted sum of the L1 norms ofsecond derivatives of the spline and the l1 norm of the residuals of the data-fitting equations. Cubic L1 smoothing splines are compared with conventional cubic smoothingsplines based on the L2 and l2 norms. Computational results for fitting a challengingdata set consisting of discontinuously connected flat and quadratic areas by C1-smooth Sibson-element splines on a tensor-product grid are presented. In these computational results, the cubic L1 smoothing splines preserve the shape of the data while cubic L2 smoothing splines do not.
Gilsinn, D.
and Lavery, J.
(2002),
Shape-Preserving, Multi-Scale Fitting of Bivariate Data by Cubic L<sub>1</sub> Smoothing Splines, Journal of Approximation Theory, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=150830
(Accessed October 16, 2025)