com.jidesoft.chart.fit
Class Polynomial

java.lang.Object
  com.jidesoft.chart.fit.Polynomial

public class Polynomial
extends Object

This class represents a polynomial of any number of terms (provided the powers of x are all positive integers).

So, for example an instance of this class can be used to represent an expression such as x - 5 or 3x² + 4x + 2

Constructor Summary

Polynomial(double... coefficients)
Create a polynomial using the supplied coefficients for successive powers of x starting from a constant.

Polynomial(Double[] coefficients)
Create a polynomial using the supplied coefficients for successive powers of x starting from a constant.

Method Summary

boolean	equals(Object obj)
double	eval(double x) Compute the value of the polynomial for a given x value.
Double	getCoefficient(int index) Returns the coefficient of the polynomial with the given index.
List<Double>	getCoefficients() Returns the coefficients of the polynomials, lowest term (i.e.
int	hashCode()
void	setCoefficients(Double[] coefficients) Specify the coefficients of the polynomial
void	setCoefficients(List<Double> coefficients) Specify the coefficients of the polynomial
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Polynomial

public Polynomial(Double[] coefficients)

Create a polynomial using the supplied coefficients for successive powers of x starting from a constant. Therefore for 2x+4, supply the arguments [4, 2].

Parameters:

coefficients - the coefficients of the successive terms of the polynomial

Polynomial

public Polynomial(double... coefficients)

Create a polynomial using the supplied coefficients for successive powers of x starting from a constant. Therefore for 2x+4, create as new Polynomial(4, 2).

Parameters:

coefficients - the coefficients of the successive terms of the polynomial

Method Detail

getCoefficients

public List<Double> getCoefficients()

Returns the coefficients of the polynomials, lowest term (i.e. the constant) first

Returns:

the coefficients of the polynomial

getCoefficient

public Double getCoefficient(int index)

Returns the coefficient of the polynomial with the given index. The constant has index of 0.

Parameters:

index - the index of the coefficient; the constant term has zero index.

Returns:

the coefficient of the term indicated

setCoefficients

public void setCoefficients(List<Double> coefficients)

Specify the coefficients of the polynomial

Parameters:

coefficients - the coefficients, given as a List of Doubles

setCoefficients

public void setCoefficients(Double[] coefficients)

Specify the coefficients of the polynomial

Parameters:

coefficients - the coefficients, given as an array of Doubles

eval

public double eval(double x)

Compute the value of the polynomial for a given x value. This works by starting at the coefficient of the highest order term and iteratively multiplying by x and adding the coefficient of the next lower term.

Parameters:

x - the x value to plug into the expression

Returns:

the value of the polynomial for the given x value.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object