ec.gp.breed
Class InternalCrossoverPipeline

java.lang.Object
  extended by ec.BreedingSource
      extended by ec.BreedingPipeline
          extended by ec.gp.GPBreedingPipeline
              extended by ec.gp.breed.InternalCrossoverPipeline
All Implemented Interfaces:
Prototype, Setup, SteadyStateBSourceForm, RandomChoiceChooser, java.io.Serializable, java.lang.Cloneable

public class InternalCrossoverPipeline
extends GPBreedingPipeline

InternalCrossoverPipeline picks two subtrees from somewhere within an individual, and crosses them over. Before doing so, it checks to make sure that the subtrees come from trees with the same tree constraints, that the subtrees are swap-compatible with each other, that the new individual does not violate depth constraints, and that one subtree does not contain the other. It tries tries times to find a valid subtree pair to cross over. Failing this, it just copies the individual.

Typical Number of Individuals Produced Per produce(...) call
...as many as the source produces

Number of Sources
1

Parameters

base.tries
int >= 1
(number of times to try finding valid pairs of nodes)
base.maxdepth
int >= 1
(maximum valid depth of the crossed-over individual's trees)
base.ns.0
classname, inherits and != GPNodeSelector
(GPNodeSelector for subtree 0.
base.ns.1
classname, inherits and != GPNodeSelector,
or String same
(GPNodeSelector for subtree 1. If value is same, then ns.1 a copy of whatever ns.0 is)
base.tree.0
0 < int < (num trees in individuals), if exists
(first tree for the crossover; if parameter doesn't exist, tree is picked at random)
base.tree.1
0 < int < (num trees in individuals), if exists
(second tree for the crossover; if parameter doesn't exist, tree is picked at random. This tree must have the same GPTreeConstraints as tree.0, if tree.0 is defined.)

Default Base
gp.breed.internal-xover

Parameter bases

base.ns.n
nodeselectn (n is 0 or 1)

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

Field Summary
 int maxDepth
          The deepest tree the pipeline is allowed to form.
 GPNodeSelector nodeselect0
          How the pipeline chooses the first subtree
 GPNodeSelector nodeselect1
          How the pipeline chooses the second subtree
static int NUM_SOURCES
           
 int numTries
          How many times the pipeline attempts to pick nodes until it gives up.
static java.lang.String P_INTERNALCROSSOVER
           
static java.lang.String P_MAXDEPTH
           
static java.lang.String P_NUM_TRIES
           
 int tree1
          Is the first tree fixed? If not, this is -1
 int tree2
          Is the second tree fixed? If not, this is -1
 
Fields inherited from class ec.gp.GPBreedingPipeline
P_NODESELECTOR, P_TREE, TREE_UNFIXED
 
Fields inherited from class ec.BreedingPipeline
DYNAMIC_SOURCES, mybase, P_NUMSOURCES, P_SOURCE, sources, V_SAME
 
Fields inherited from class ec.BreedingSource
CHECKBOUNDARY, DEFAULT_PRODUCED, NO_PROBABILITY, P_PROB, probability, UNUSED
 
Constructor Summary
InternalCrossoverPipeline()
           
 
Method Summary
 java.lang.Object clone()
          Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.
 Parameter defaultBase()
          Returns the default base for this prototype.
 int numSources()
          Returns the number of sources to this pipeline.
 int produce(int min, int max, int start, int subpopulation, Individual[] inds, EvolutionState state, int thread)
          Produces n individuals from the given subpopulation and puts them into inds[start...start+n-1], where n = Min(Max(q,min),max), where q is the "typical" number of individuals the BreedingSource produces in one shot, and returns n.
 void setup(EvolutionState state, Parameter base)
          Sets up the BreedingPipeline.
 
Methods inherited from class ec.gp.GPBreedingPipeline
produces
 
Methods inherited from class ec.BreedingPipeline
finishProducing, individualReplaced, maxChildProduction, minChildProduction, preparePipeline, prepareToProduce, sourcesAreProperForm, typicalIndsProduced
 
Methods inherited from class ec.BreedingSource
getProbability, pickRandom, setProbability, setupProbabilities
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

P_INTERNALCROSSOVER

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

P_NUM_TRIES

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

P_MAXDEPTH

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

NUM_SOURCES

public static final int NUM_SOURCES
See Also:
Constant Field Values

nodeselect0

public GPNodeSelector nodeselect0
How the pipeline chooses the first subtree


nodeselect1

public GPNodeSelector nodeselect1
How the pipeline chooses the second subtree


numTries

public int numTries
How many times the pipeline attempts to pick nodes until it gives up.


maxDepth

public int maxDepth
The deepest tree the pipeline is allowed to form. Single terminal trees are depth 1.


tree1

public int tree1
Is the first tree fixed? If not, this is -1


tree2

public int tree2
Is the second tree fixed? If not, this is -1

Constructor Detail

InternalCrossoverPipeline

public InternalCrossoverPipeline()
Method Detail

defaultBase

public Parameter defaultBase()
Description copied from interface: Prototype
Returns the default base for this prototype. This should generally be implemented by building off of the static base() method on the DefaultsForm object for the prototype's package. This should be callable during setup(...).


numSources

public int numSources()
Description copied from class: BreedingPipeline
Returns the number of sources to this pipeline. Called during BreedingPipeline's setup. Be sure to return a value > 0, or DYNAMIC_SOURCES which indicates that setup should check the parameter file for the parameter "num-sources" to make its determination.

Specified by:
numSources in class BreedingPipeline

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 BreedingPipeline

setup

public void setup(EvolutionState state,
                  Parameter base)
Description copied from class: BreedingSource
Sets up the BreedingPipeline. You can use state.output.error here because the top-level caller promises to call exitIfErrors() after calling setup. Note that probability might get modified again by an external source if it doesn't normalize right.

The most common modification is to normalize it with some other set of probabilities, then set all of them up in increasing summation; this allows the use of the fast static BreedingSource-picking utility method, BreedingSource.pickRandom(...). In order to use this method, for example, if four breeding source probabilities are {0.3, 0.2, 0.1, 0.4}, then they should get normalized and summed by the outside owners as: {0.3, 0.5, 0.6, 1.0}.

Specified by:
setup in interface Prototype
Specified by:
setup in interface Setup
Overrides:
setup in class BreedingPipeline
See Also:
Prototype.setup(EvolutionState,Parameter)

produce

public int produce(int min,
                   int max,
                   int start,
                   int subpopulation,
                   Individual[] inds,
                   EvolutionState state,
                   int thread)
Description copied from class: BreedingSource
Produces n individuals from the given subpopulation and puts them into inds[start...start+n-1], where n = Min(Max(q,min),max), where q is the "typical" number of individuals the BreedingSource produces in one shot, and returns n. max must be >= min, and min must be >= 1. For example, crossover might typically produce two individuals, tournament selection might typically produce a single individual, etc.

Specified by:
produce in class BreedingSource