[MATH-1650] Add clamped spline interpolation

• Type: New Feature
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 4.X
• Labels: Polynomials interpolation spline
• Flags: Patch

Language

english

• difficulty-level: Medium
• required-knowledge: desired structure of package org.apache.commons.math4.legacy.analysis.interpolation

useful-knowledge

detailed knowledge of org.​apache.​commons.​math4.​legacy.​analysis.​interpolation.UnivariateInterpolator and its subclasses

general knowledge around polynomial functions

• Assignee: Unassigned
• Reporter: Michael Scholz

potential-mentor

Gilles Sadowski

• Created: 05/Oct/22 16:36
• Updated: 02/Oct/24 13:07

Description

We would like to contribute a new clamped spline interpolation function in addition to the already available unclamped spline function. Our new ClampedSplineInterpolator is based on the same textbook as the original SplineInterpolator. The clamped spline offers additional parameterisation of starting and ending slopes (1st derivatives) as boundary conditions in order to provide more flexibility in spline creation.

In this patch we follow the approach of subclassing the original SplineInterpolator and simply overloading it's interpolate() function by these two additional parameters. Is this an acceptable way or does the community recommend a different design approach?

After clarifying the basic implementation approach we could also supply necessary tests etc. and finally contribute everything via ordinary GitHub pull request.

Refer to our post on the dev mailing list: https://lists.apache.org/thread/34qnx4tgjbyv345lgmd57g0bnlnwdzc8