com.epochx.representation.dbl
Class ProtectedDivisionFunction

java.lang.Object
  com.epochx.representation.Node<TYPE>
      com.epochx.representation.FunctionNode<java.lang.Double>
          com.epochx.representation.dbl.ProtectedDivisionFunction

All Implemented Interfaces:

java.lang.Cloneable

public class ProtectedDivisionFunction
extends FunctionNode<java.lang.Double>

A FunctionNode which performs the arithmetic function of division. The division is protected to avoid the scenario where division by zero is attempted - which is undefined. Division by zero evaluates to zero.

Constructor Summary

ProtectedDivisionFunction()
Construct a ProtectedDivisionFunction with no children.

ProtectedDivisionFunction(java.lang.Double protectionValue)
Construct a ProtectedDivisionFunction with a protection value to assign during divide-by-zero.

ProtectedDivisionFunction(Node<java.lang.Double> dividend, Node<java.lang.Double> divisor)
Construct a ProtectedDivisionFunction with 2 children.

ProtectedDivisionFunction(Node<java.lang.Double> dividend, Node<java.lang.Double> divisor, java.lang.Double protectionValue)
Construct a ProtectedDivisionFunction with 2 children and a divide-by-zero protection value.

Method Summary

java.lang.Double	evaluate() Evaluating a ProtectedDivisionFunction involves dividing the result of evaluating both children.
java.lang.String	getFunctionName() Get the unique name that identifies this function.

Methods inherited from class com.epochx.representation.FunctionNode

equals, toString

Methods inherited from class com.epochx.representation.Node

clone, getArity, getChild, getChildren, getDepth, getFunctionNodes, getLength, getNodesAtDepth, getNoDistinctFunctions, getNoDistinctTerminals, getNoFunctions, getNoTerminals, getNthNode, getTerminalNodes, hashCode, setChild, setChildren, setNthNode

Methods inherited from class java.lang.Object

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

Constructor Detail

ProtectedDivisionFunction

public ProtectedDivisionFunction()

Construct a ProtectedDivisionFunction with no children. A default protection value that is returned in the case of divide-by-zero is set as 0.0.

ProtectedDivisionFunction

public ProtectedDivisionFunction(java.lang.Double protectionValue)

Construct a ProtectedDivisionFunction with a protection value to assign during divide-by-zero. This overrides the default protection value of 0.0.

Parameters:

protectionValue - a double value to return in the case of divide-by-zeros.

ProtectedDivisionFunction

public ProtectedDivisionFunction(Node<java.lang.Double> dividend,
                                 Node<java.lang.Double> divisor)

Construct a ProtectedDivisionFunction with 2 children. When evaluated, the evaluation of the first child will be divided by the evaluation of the second. A default protection value that is returned in the case of divide-by-zero is set as 0.0.

Parameters:

dividend - The first child node - the dividend.

divisor - The second child node - the divisor.

ProtectedDivisionFunction

public ProtectedDivisionFunction(Node<java.lang.Double> dividend,
                                 Node<java.lang.Double> divisor,
                                 java.lang.Double protectionValue)

Construct a ProtectedDivisionFunction with 2 children and a divide-by-zero protection value. When evaluated, the evaluation of the first child will be divided by the evaluation of the second. If the second (divisor) child evaluates to zero, then no division takes place and the specified protectionValue is returned.

Parameters:

dividend - The first child node - the dividend.

divisor - The second child node - the divisor.

protectionValue - a double value to return in the case of divide-by-zeros.

Method Detail

evaluate

public java.lang.Double evaluate()

Evaluating a ProtectedDivisionFunction involves dividing the result of evaluating both children. If the divisor resolves to zero then the result returned will be zero to avoid the divide by zero issue.

Specified by:

evaluate in class Node<java.lang.Double>

Returns:

The result of evaluating the candidate program.

getFunctionName

public java.lang.String getFunctionName()

Get the unique name that identifies this function.

Specified by:

getFunctionName in class FunctionNode<java.lang.Double>

Returns:

the unique name for the ProtectedDivisionFunction which is PDIV.