org.esa.snap.core.datamodel

Class RationalFunctionModel

java.lang.Object

org.esa.snap.core.datamodel.RationalFunctionModel

All Implemented Interfaces:

Cloneable

public class RationalFunctionModel
extends Object
implements Cloneable

Class for approximating a function of two variables with a rational function.

Version:

$Revision$ $Date$

Constructor Summary

Constructors

Constructor and Description
RationalFunctionModel(int degreeP, int degreeQ, double[] x, double[] y, double[] g) Constructs a rational function model for approximating a function g(x, y) with a rational function R(x, y) = P(x, y) / Q(x, y) where P and Q are polynomials of up to 4th degree.

Method Summary

Modifier and Type	Method and Description
String	createCFunctionCode(String compute_x, String lat, String lon)
double	getMaxError() Returns the maximum error of the approximation.
double	getRmse() Returns the root mean square error (RMSE) of the approximation.
static int	getTermCountP(int degreeP)
static int	getTermCountQ(int degreeQ)
double	getValue(double x, double y) Returns the rational function value approximating g(x, y).

Methods inherited from class java.lang.Object

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

Constructor Detail

RationalFunctionModel

public RationalFunctionModel(int degreeP,
                             int degreeQ,
                             double[] x,
                             double[] y,
                             double[] g)

Constructs a rational function model for approximating a function g(x, y) with a rational function R(x, y) = P(x, y) / Q(x, y) where P and Q are polynomials of up to 4th degree.

Parameters:

degreeP - the degree of the numerator polynomial P.

degreeQ - the degree of the denominator polynomial Q.

x - the x-coordinates corresponding to the function values being approximated.

y - the y-coordinates corresponding to the function values being approximated.

g - the function values g(x, y) being approximated.

Throws:

IllegalArgumentException - if the degree of the numerator or denominator polynomial is greater than four.

IllegalArgumentException - if the lengths of x, y, and g are not the same.

Method Detail

getTermCountP

public static int getTermCountP(int degreeP)

getTermCountQ

public static int getTermCountQ(int degreeQ)

getValue

public double getValue(double x,
                       double y)

Returns the rational function value approximating g(x, y).

Parameters:

x - the x-coordinate.

y - the y-coordinate.

Returns:

the rational function value R(x, y).

getRmse

public double getRmse()

Returns the root mean square error (RMSE) of the approximation.

Returns:

the root mean square error.

getMaxError

public double getMaxError()

Returns the maximum error of the approximation.

Returns:

the maximum error.

createCFunctionCode

public String createCFunctionCode(String compute_x,
                                  String lat,
                                  String lon)