jhpro.interpolator

Class ConstrainedSplineInterpolator

java.lang.Object

jhpro.interpolator.ConstrainedSplineInterpolator

All Implemented Interfaces:

UnivariateInterpolator

public class ConstrainedSplineInterpolator
extends java.lang.Object
implements UnivariateInterpolator

Constrained Spline Interpolation algorithm (CJC Kruger). If we want to avoid overshoot for an arbitrary function, we should find some other interpolation algorithm. One of the methods is called Constrained Cubic Spline Interpolation. It was proposed by CJC Kruger in his article: http://www.korf.co.uk/spline.pdf The algorithms is based on a classic cubic spline algorithm. The key step in it is the calculation of the slope (first derivative) at each point. Intuitively, the slope will be between the slopes of the adjacent straight lines (can be a mean value of the two slopes), but it also should approach zero if the slope of either line approaches zero.

 import android.util.Spline;
 float x[] = ...
 float y[[] = ...
 Spline f = Spline.createMonotoneCubicSpline(x, y);
 
// this will evaluate y0 = f(x0)
 float y0 = f.interpolate(x0);
 

Created by Anton Danshin on 24/12/14.

Constructor Summary

Constructors

Constructor and Description
ConstrainedSplineInterpolator()

Method Summary

Modifier and Type	Method and Description
PolynomialSplineFunction	interpolate(double[] x, double[] y) Compute an interpolating function for the dataset.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ConstrainedSplineInterpolator

public ConstrainedSplineInterpolator()

Method Detail

interpolate

public PolynomialSplineFunction interpolate(double[] x,
                                            double[] y)
                                     throws DimensionMismatchException,
                                            NumberIsTooSmallException,
                                            NonMonotonicSequenceException

Description copied from interface: UnivariateInterpolator

Compute an interpolating function for the dataset.

Specified by:

interpolate in interface UnivariateInterpolator

Parameters:

x - Arguments for the interpolation points.

y - Values for the interpolation points.

Returns:

a function which interpolates the dataset.

Throws:

DimensionMismatchException - if arrays lengthes do not match

NumberIsTooSmallException

NonMonotonicSequenceException