org.mathIT.approximation

Class Interpolation

java.lang.Object

org.mathIT.approximation.Interpolation

public class Interpolation
extends Object

This class enables to generate objects from data points (x, y) such as time series and to compute interpolation polynomials from them. There are multiple data series possible, i.e., y is an array.

Version:

1.1

Author:

Andreas de Vries

Constructor Summary

Constructors

Constructor and Description
Interpolation(double[] xValues, double[][] yValues) Creates a new instance of Interpolation.

Method Summary

Modifier and Type	Method and Description
double[]	getXValues() Returns the x-values of the data points (x, y).
double[][]	getYValues() Returns the array of y-values of the data points (x, y).
double[]	piecewiseLinear(double x) piecewise linear continuous function interpolating between the x-y values.
double[]	polynomial(double x) Returns the value at x of the polynomial interpolating through the given data points, as given by Lagrange's classical formula.

Methods inherited from class java.lang.Object

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

Constructor Detail

Interpolation

public Interpolation(double[] xValues,
                     double[][] yValues)

Creates a new instance of Interpolation.

Parameters:

xValues - the x-values of the data points (x, y)

yValues - an array of the y-values of the data points (x, y)

Method Detail

getXValues

public double[] getXValues()

Returns the x-values of the data points (x, y).

Returns:

the x-values of the data points

getYValues

public double[][] getYValues()

Returns the array of y-values of the data points (x, y).

Returns:

the y-values of the data points

piecewiseLinear

public double[] piecewiseLinear(double x)

piecewise linear continuous function interpolating between the x-y values.

Parameters:

x - a data point

Returns:

the y-values for each curve at x

polynomial

public double[] polynomial(double x)

Returns the value at x of the polynomial interpolating through the given data points, as given by Lagrange's classical formula. If there are n data points, the polynomial has degree n.

Parameters:

x - a data point

Returns:

the y-values for each curve

Throws:

IllegalArgumentException - if there exist two identical x-values