ec.gp
Class GPNodeBuilder

java.lang.Object
  extended by ec.gp.GPNodeBuilder
All Implemented Interfaces:
Prototype, Setup, java.io.Serializable, java.lang.Cloneable
Direct Known Subclasses:
KozaBuilder, PTC1, PTC2, RandomBranch, RandTree, Uniform

public abstract class GPNodeBuilder
extends java.lang.Object
implements Prototype

GPNodeBuilder is a Prototype which defines the superclass for objects which create ("grow") GP trees, whether for population initialization, subtree mutation, or whatnot. It defines a single abstract method, newRootedTree(...), which must be implemented to grow the tree.

GPNodeBuilder also provides some facilities for user-specification of probabilities of various tree sizes, which the tree builder can use as it sees fit (or totally ignore). There are two such facilities. First, the user might specify a minimum and maximum range for tree sizes to be picked from; trees would likely be picked uniformly from this range. Second, the user might specify an array, num-sizes long, of probabilities of tree sizes, in order to give a precise probability distribution.

Parameters

base.min-size
int >= 1, or undefined
(smallest valid size, see discussion above)
base.max-size
int >= min-size, or undefined
(largest valid size, see discussion above)
base.num-sizes
int >= 1, or underfined
(number of sizes in the size distribution, see discussion above)
base.size.n
0.0 <= float <= 1.0, or undefined
(probability of choosing size n. See discussion above)

Version:
1.0
Author:
Sean Luke
See Also:
Serialized Form

Field Summary
static int CHECK_BOUNDARY
           
 int maxSize
          the minium possible size -- if unused, it's 0
 int minSize
           
static int NOSIZEGIVEN
          Produces a new rooted tree of GPNodes whose root's return type is swap-compatible with type.
static java.lang.String P_MAXSIZE
           
static java.lang.String P_MINSIZE
           
static java.lang.String P_NUMSIZES
           
static java.lang.String P_SIZE
           
 float[] sizeDistribution
          the maximum possible size -- if unused, it's 0
 
Constructor Summary
GPNodeBuilder()
           
 
Method Summary
 boolean canPick()
          Returns true if some size distribution (either minSize and maxSize, or sizeDistribution) is set up by the user in order to pick sizes randomly.
 java.lang.Object clone()
          Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.
protected  void errorAboutNoNodeWithType(GPType type, EvolutionState state)
          Issues a fatal error that no node (nonterminal or terminal) was found with a return type of the given type, and that an algorithm had requested one.
abstract  GPNode newRootedTree(EvolutionState state, GPType type, int thread, GPNodeParent parent, GPFunctionSet set, int argposition, int requestedSize)
           
 int pickSize(EvolutionState state, int thread)
          Assuming that either minSize and maxSize, or sizeDistribution, is defined, picks a random size from minSize...maxSize inclusive, or randomly from sizeDistribution.
 void setup(EvolutionState state, Parameter base)
          Sets up the object by reading it from the parameters stored in state, built off of the parameter base base.
protected  boolean warnAboutNonterminal(boolean test, GPType type, boolean fail, EvolutionState state)
          If the given test is true, issues a warning that no terminal was found with a return type of the given type, and that an algorithm had requested one.
protected  void warnAboutNonTerminalWithType(GPType type, boolean fail, EvolutionState state)
          Issues a warning that no nonterminal was found with a return type of the given type, and that an algorithm had requested one.
protected  void warnAboutNoTerminalWithType(GPType type, boolean fail, EvolutionState state)
          Issues a warning that no terminal was found with a return type of the given type, and that an algorithm had requested one.
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface ec.Prototype
defaultBase
 

Field Detail

NOSIZEGIVEN

public static final int NOSIZEGIVEN
Produces a new rooted tree of GPNodes whose root's return type is swap-compatible with type. When you build a brand-new tree out of GPNodes cloned from the prototypes stored in the GPNode[] arrays, you must remember to call resetNode() on each cloned GPNode. This gives ERCs a chance to randomize themselves and set themselves up.

requestedSize is an optional argument which differs based on the GPNodeBuilder used. Typically it is set to a tree size that the calling method wants the GPNodeBuilder to produce; the GPNodeBuilder is not obligated to produce a tree of this size, but it should attempt to interpret this argument as appropriate for the given algorithm. To indicate that you don't care what size the tree should be, you can pass NOSIZEGIVEN. However if the algorithm requires you to provide a size, it will generate a fatal error to let you know.

See Also:
Constant Field Values

CHECK_BOUNDARY

public static final int CHECK_BOUNDARY
See Also:
Constant Field Values

P_MINSIZE

public static final java.lang.String P_MINSIZE
See Also:
Constant Field Values

P_MAXSIZE

public static final java.lang.String P_MAXSIZE
See Also:
Constant Field Values

P_NUMSIZES

public static final java.lang.String P_NUMSIZES
See Also:
Constant Field Values

P_SIZE

public static final java.lang.String P_SIZE
See Also:
Constant Field Values

minSize

public int minSize

maxSize

public int maxSize
the minium possible size -- if unused, it's 0


sizeDistribution

public float[] sizeDistribution
the maximum possible size -- if unused, it's 0

Constructor Detail

GPNodeBuilder

public GPNodeBuilder()
Method Detail

canPick

public boolean canPick()
Returns true if some size distribution (either minSize and maxSize, or sizeDistribution) is set up by the user in order to pick sizes randomly.


pickSize

public int pickSize(EvolutionState state,
                    int thread)
Assuming that either minSize and maxSize, or sizeDistribution, is defined, picks a random size from minSize...maxSize inclusive, or randomly from sizeDistribution.


clone

public java.lang.Object clone()
Description copied from interface: Prototype
Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.

Typically this should be a full "deep" clone. However, you may share certain elements with other objects rather than clone hem, depending on the situation:

Implementations.

Specified by:
clone in interface Prototype
Overrides:
clone in class java.lang.Object

setup

public void setup(EvolutionState state,
                  Parameter base)
Description copied from interface: Prototype
Sets up the object by reading it from the parameters stored in state, built off of the parameter base base. If an ancestor implements this method, be sure to call super.setup(state,base); before you do anything else.

For prototypes, setup(...) is typically called once for the prototype instance; cloned instances do not receive the setup(...) call. setup(...) may be called more than once; the only guarantee is that it will get called at least once on an instance or some "parent" object from which it was ultimately cloned.

Specified by:
setup in interface Prototype
Specified by:
setup in interface Setup

newRootedTree

public abstract GPNode newRootedTree(EvolutionState state,
                                     GPType type,
                                     int thread,
                                     GPNodeParent parent,
                                     GPFunctionSet set,
                                     int argposition,
                                     int requestedSize)

warnAboutNoTerminalWithType

protected void warnAboutNoTerminalWithType(GPType type,
                                           boolean fail,
                                           EvolutionState state)
Issues a warning that no terminal was found with a return type of the given type, and that an algorithm had requested one. If fail is true, then a fatal is issued rather than a warning. The warning takes the form of a one-time big explanatory message, followed by a one-time-per-type message.


warnAboutNonterminal

protected boolean warnAboutNonterminal(boolean test,
                                       GPType type,
                                       boolean fail,
                                       EvolutionState state)
If the given test is true, issues a warning that no terminal was found with a return type of the given type, and that an algorithm had requested one. If fail is true, then a fatal is issued rather than a warning. The warning takes the form of a one-time big explanatory message, followed by a one-time-per-type message. Returns the value of the test. This form makes it easy to insert warnings into if-statements.


warnAboutNonTerminalWithType

protected void warnAboutNonTerminalWithType(GPType type,
                                            boolean fail,
                                            EvolutionState state)
Issues a warning that no nonterminal was found with a return type of the given type, and that an algorithm had requested one. If fail is true, then a fatal is issued rather than a warning. The warning takes the form of a one-time big explanatory message, followed by a one-time-per-type message.


errorAboutNoNodeWithType

protected void errorAboutNoNodeWithType(GPType type,
                                        EvolutionState state)
Issues a fatal error that no node (nonterminal or terminal) was found with a return type of the given type, and that an algorithm had requested one.