Package noaa.coastwatch.util

Class UnivariateEstimator

java.lang.Object

noaa.coastwatch.util.Function

noaa.coastwatch.util.UnivariateEstimator

All Implemented Interfaces:

Encodable

public class UnivariateEstimator
extends Function

A univariate estimator approximates the value of a function of one variable using a set of known function values. If the function values are given by [x1, x2, ... xn] then an estimator is set up based on the function values using a polynomial of user-specified degree. Suppose that the desired polynomial degree is 2 so that the polynomial is a quadratic. Then a series of 3 coefficients a0, a1, a2 are calculated using the values, and the estimator will approximate function values using the coefficients as f(x) = a0 + a1x + a2x2.

Since:

3.1.0

Author:

Peter Hollemans

Constructor Summary

Constructors

Constructor	Description
UnivariateEstimator(double[] x, double[] f, int degree)	Constructs a univariate estimator using the specified function values and polynomial degree.
UnivariateEstimator(Object obj)	Constructs an estimator from the specified encoding.

Method Summary

Modifier and Type	Method	Description
double	evaluate(double[] variables)	Evalutes a function value with the specified inputs.
Object	getEncoding()	Gets an encoded representation of this estimator.
void	useEncoding(Object obj)	Uses an encoded representation of this estimator to recreate the estimator contents.

Methods inherited from class java.lang.Object

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

Constructor Details

UnivariateEstimator

public UnivariateEstimator(double[] x,
 double[] f,
 int degree)

Constructs a univariate estimator using the specified function values and polynomial degree.

Parameters:

x - the array of x values.

f - the function values at x points.

degree - the desired polynomial degree.

UnivariateEstimator

public UnivariateEstimator(Object obj)

Constructs an estimator from the specified encoding. The encoding must be a valid encoding of the estimator as created by getEncoding.

Parameters:

obj - the object encoding.

See Also:

• getEncoding()

Method Details

evaluate

public double evaluate(double[] variables)

Description copied from class: Function

Evalutes a function value with the specified inputs.

Specified by:

evaluate in class Function

Parameters:

variables - the array of input variable values.

Returns:

the evaluated function value. If an error occurred during evaluation, the return value is Double.NaN.

getEncoding

public Object getEncoding()

Gets an encoded representation of this estimator. The encoding may later be used to recreate the estimator without using the original function data.

Specified by:

getEncoding in interface Encodable

Overrides:

getEncoding in class Function

Returns:

the object encoding. The encoding object is a double[] array of coefficients.

See Also:

• useEncoding(java.lang.Object)

useEncoding

public void useEncoding(Object obj)

Uses an encoded representation of this estimator to recreate the estimator contents.

Specified by:

useEncoding in interface Encodable

Overrides:

useEncoding in class Function

Parameters:

obj - the object encoding.

See Also:

• getEncoding()