uk.ac.starlink.diva.interp

Class HermiteSplineInterp

java.lang.Object

uk.ac.starlink.diva.interp.AbstractInterpolator

uk.ac.starlink.diva.interp.LinearInterp

uk.ac.starlink.diva.interp.HermiteSplineInterp

All Implemented Interfaces:

Interpolator

public class HermiteSplineInterp
extends LinearInterp

Spline interpolate a series of points using a scheme based on Hermite polynomials.

Based on the the code from G. Hill, Publ. DAO, vol 16, no. 6 (1982) which uses US Airforce Surveys in Geophysics no. 272 as its source.

The effect is supposed to construct reasonable analytic curves through discrete data points (i.e. like those a human would produce).

Version:

$Id$

Author:

Peter W. Draper

Field Summary

Fields inherited from class uk.ac.starlink.diva.interp.AbstractInterpolator

c, decr, x, y

Constructor Summary

Constructors

Constructor and Description
HermiteSplineInterp() Create an instance with no coordinates.
HermiteSplineInterp(double[] x, double[] y) Create an instance with the given coordinates.

Method Summary

Modifier and Type	Method and Description
double	interpolate(double xp) Return the interpolated value corresponding to some arbitrary X coordinate.
static void	main(String[] args) Simple test entry point.

Methods inherited from class uk.ac.starlink.diva.interp.LinearInterp

guessStep

Methods inherited from class uk.ac.starlink.diva.interp.AbstractInterpolator

appendValue, binarySearch, evalYData, evalYDataArray, getCount, getXCoord, getXCoords, getYCoord, getYCoords, isFull, isIncreasing, setCoords, stepGuess

Methods inherited from class java.lang.Object

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

Constructor Detail

HermiteSplineInterp

public HermiteSplineInterp()

Create an instance with no coordinates. A call to setCoords must be made before any other methods.

HermiteSplineInterp

public HermiteSplineInterp(double[] x,
                           double[] y)

Create an instance with the given coordinates. Interpolation is by X coordinate see the interpolate method. The X coordinates should be monotonic, either increasing or decreasing. Same value X coordinates are not allowed.

Parameters:

x - the X coordinates.

y - the Y coordinates.

Method Detail

interpolate

public double interpolate(double xp)

Description copied from interface: Interpolator

Return the interpolated value corresponding to some arbitrary X coordinate.

Specified by:

interpolate in interface Interpolator

Overrides:

interpolate in class LinearInterp

Parameters:

xp - the X coordinate at which an interpolated Y coordinate is required.

Returns:

the interpolated value.

main

public static void main(String[] args)

Simple test entry point.