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Class gpjpp.GPNodeSet

java.lang.Object
   |
   +----gpjpp.GPObject
           |
           +----gpjpp.GPContainer
                   |
                   +----gpjpp.GPNodeSet

public class GPNodeSet

extends GPContainer

GPNodeSet is a container that holds an arbitrary number of function and terminal nodes. For improved performance during some operations, all of the functions are stored at the beginning of the container and all of the terminals are stored at the end. There might be some null elements in the middle and the code is designed to accommodate those.

Version:

1.0

See Also:

GPNode, GPAdfNodeSet

numFunctions

The number of function node types supported by this branch.

numTerminals

The number of terminal node types supported by this branch.

GPNodeSet()

Public null constructor used during stream loading only.

GPNodeSet(GPNodeSet)

A constructor that can be called to clone a GPNodeSet.

GPNodeSet(int)

The constructor called by user code to reserve space for the functions and terminals allowed in this branch.

chooseFunction()

Returns a random function node from this set.

chooseNodeWithArgs(int)

Returns a random node from this set with the specified number of arguments.

chooseTerminal()

Returns a random terminal node from this set.

clone()

Implements the Cloneable interface.

equals(Object)

Determines whether this GPNodeSet equals another object.

functions()

Returns the number of functions in this node set.

isA()

Returns a code identifying the class in a stream file.

load(DataInputStream)

Loads a GPNodeSet from the specified stream.

printOn(PrintStream, GPVariables)

Writes a GPNodeSet in text format to a PrintStream.

putNode(GPNode)

Adds a function or terminal node to a GPNodeSet.

save(DataOutputStream)

Saves a GPNodeSet to the specified stream.

searchForNode(int)

Returns the GPNode in this set that has the specified node value, or null if none is found.

terminals()

Returns the number of terminals in this node set.

  protected int numFunctions

The number of function node types supported by this branch.

  protected int numTerminals

The number of terminal node types supported by this branch.

  public GPNodeSet()

Public null constructor used during stream loading only.

  public GPNodeSet(int numOfNodes)

The constructor called by user code to reserve space for the functions and terminals allowed in this branch.

Parameters:

numOfNodes - the maximum number of functions and terminals to be specified. This can exceed the actual number added subsequently by calling putNode but should generally equal the actual number.

  public GPNodeSet(GPNodeSet gpo)

A constructor that can be called to clone a GPNodeSet. Normally not used.

  protected synchronized Object clone()

Implements the Cloneable interface. This clones a GPNodeSet but is normally not used.

Returns:

the cloned object.

Overrides:

clone in class GPContainer

  public byte isA()

Returns a code identifying the class in a stream file.

Returns:

the ID code NODESETID.

Overrides:

isA in class GPContainer

  public int functions()

Returns the number of functions in this node set.

See Also:

numFunctions

  public int terminals()

Returns the number of terminals in this node set.

See Also:

numTerminals

  public void putNode(GPNode gpo)

Adds a function or terminal node to a GPNodeSet. Functions are automatically stored at the next available location at the start of the container, while terminals are added at the end of the container. Do not call GPContainer.put() to store nodes in a GPNodeSet since this may corrupt the expected ordering of the nodes.

Parameters:

gpo - a non-null GPNode instance.

Throws: ArrayStoreException

if the container is already full.

Throws: RuntimeException

if a node with gpo's value is already found in the GPNodeSet.

  public boolean equals(Object obj)

Determines whether this GPNodeSet equals another object. It returns true if obj is not null, is an instance of a GPNodeSet (or a descendant), and contains the same GPNode values. This function is called when a checkpoint is loaded by GPRun, to determine whether the program and the checkpoint are consistent.

Parameters:

obj - any Java object reference, including null.

Returns:

true if this and obj are equivalent.

Overrides:

equals in class Object

  protected GPNode searchForNode(int value)

Returns the GPNode in this set that has the specified node value, or null if none is found. For internal use.

  public GPNode chooseFunction()

Returns a random function node from this set. Used by GP.create() and GPGene.create() to build new trees.

  public GPNode chooseTerminal()

Returns a random terminal node from this set. Used by GPGene.create() to build new trees.

  public GPNode chooseNodeWithArgs(int args)

Returns a random node from this set with the specified number of arguments. Returns null if there is no such node. Used for swap mutation.

  protected synchronized void load(DataInputStream is) throws ClassNotFoundException, IOException, InstantiationException, IllegalAccessException

Loads a GPNodeSet from the specified stream. Reads the numFunctions and numTerminals fields from the stream and then loads the container.

Throws: ClassNotFoundException

if the class indicated by the stream's ID code is not registered with GPObject.

Throws: InstantiationException

if an error occurs while calling new or the null constructor of the specified class.

Throws: IllegalAccessException

if the specified class or its null constructor is not public.

Throws: IOException

if an error occurs while reading the stream.

Overrides:

load in class GPContainer

  protected void save(DataOutputStream os) throws IOException

Saves a GPNodeSet to the specified stream. Writes the numFunctions and numTerminals fields to the stream and then stores the container.

Throws: IOException

if an error occurs while writing the stream.

Overrides:

save in class GPContainer

  public void printOn(PrintStream os,
                      GPVariables cfg)

Writes a GPNodeSet in text format to a PrintStream. Each node is printed as its representation string followed by its number of arguments, if any.

Overrides:

printOn in class GPContainer

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