org.apache.commons.math3.analysis.function
Class Sinc

java.lang.Object
  extended by org.apache.commons.math3.analysis.function.Sinc
All Implemented Interfaces:
DifferentiableUnivariateFunction, UnivariateFunction

public class Sinc
extends Object
implements DifferentiableUnivariateFunction

Sinc function, defined by


   sinc(x) = 1            if x = 0,
             sin(x) / x   otherwise.
 

Since:
3.0
Version:
$Id$

Field Summary
private  boolean normalized
          For normalized sinc function.
private static double SHORTCUT
          Value below which the result of the computation will not change anymore due to the finite precision of the "double" representation of real numbers.
 
Constructor Summary
Sinc()
          The sinc function, sin(x) / x.
Sinc(boolean normalized)
          Instantiates the sinc function.
 
Method Summary
 UnivariateFunction derivative()
          Returns the derivative of the function
private static double sinc(double x)
           
private static double sincDerivative(double x)
           
 double value(double x)
          Compute the value of the function.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SHORTCUT

private static final double SHORTCUT
Value below which the result of the computation will not change anymore due to the finite precision of the "double" representation of real numbers.

See Also:
Constant Field Values

normalized

private final boolean normalized
For normalized sinc function.

Constructor Detail

Sinc

public Sinc()
The sinc function, sin(x) / x.


Sinc

public Sinc(boolean normalized)
Instantiates the sinc function.

Parameters:
normalized - If true, the function is sin(πx) / πx, otherwise sin(x) / x.
Method Detail

value

public double value(double x)
Compute the value of the function.

Specified by:
value in interface UnivariateFunction
Parameters:
x - Point at which the function value should be computed.
Returns:
the value of the function.

derivative

public UnivariateFunction derivative()
Returns the derivative of the function

Specified by:
derivative in interface DifferentiableUnivariateFunction
Returns:
the derivative function

sinc

private static double sinc(double x)
Parameters:
x - Argument.
Returns:
sin(x) / x.

sincDerivative

private static double sincDerivative(double x)
Parameters:
x - Argument.
Returns:
(cos(x) - sin(x) / x) / x.


Copyright (c) 2003-2013 Apache Software Foundation