ec.gp
Class ADFArgument

java.lang.Object
  extended by ec.gp.GPNode
      extended by ec.gp.ADFArgument
All Implemented Interfaces:
GPNodeParent, Prototype, Setup, java.io.Serializable, java.lang.Cloneable

public class ADFArgument
extends GPNode

An ADFArgument is a GPNode which represents an ADF's argument terminal, its counterpart which returns argument values in its associated function tree. In lil-gp this is called an ARG node.

Obviously, if you have Argument Terminals in a tree, that tree must be only callable by ADFs and ADMs, otherwise the Argument Terminals won't have anything to return. Furthermore, you must make sure that you don't have an Argument Terminal in a tree whose number is higher than the smallest arity (number of arguments) of a calling ADF or ADM.

Parameters

base.arg
int >= 0
(The related argument position for the ADF Argument Node in the associated ADF)

Default Base
gp.adf-argument

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

Field Summary
static java.lang.String P_ADFARGUMENT
           
static java.lang.String P_ARGUMENT
           
 
Fields inherited from class ec.gp.GPNode
argposition, children, constraints, GPNODEPRINTTAB, MAXPRINTBYTES, NODESEARCH_ALL, NODESEARCH_CUSTOM, NODESEARCH_NONTERMINALS, NODESEARCH_TERMINALS, P_NODE, P_NODECONSTRAINTS, parent, REPLACEMENT_CHAR, SITUATION_MUTATION, SITUATION_NEWIND
 
Constructor Summary
ADFArgument()
           
 
Method Summary
 Parameter defaultBase()
          The default base for GPNodes -- defined even though GPNode is abstract so you don't have to in subclasses.
 void eval(EvolutionState state, int thread, GPData input, ADFStack stack, GPIndividual individual, Problem problem)
          Evaluates the node with the given thread, state, individual, problem, and stack.
 void readNode(EvolutionState state, java.io.DataInput dataInput)
          Override this to read any additional node-specific information from dataInput besides: the number of arguments, the specific node class, the children, and the parent.
 void setup(EvolutionState state, Parameter base)
          Sets up a prototypical GPNode with those features all nodes of that prototype share, and nothing more.
 java.lang.String toString()
          Returns a Lisp-like atom for the node which can be read in again by computer.
 void writeNode(EvolutionState state, java.io.DataOutput dataOutput)
          Override this to write any additional node-specific information to dataOutput besides: the number of arguments, the specific node class, the children, and the parent.
 
Methods inherited from class ec.gp.GPNode
atDepth, checkConstraints, clone, cloneReplacing, cloneReplacing, cloneReplacing, cloneReplacingAtomic, cloneReplacingAtomic, cloneReplacingNoSubclone, constraints, contains, depth, errorInfo, lightClone, makeCTree, makeLatexTree, nodeEquals, nodeEquivalentTo, nodeHashCode, nodeInPosition, numNodes, numNodes, parentType, printNode, printNode, printNodeForHumans, printRootedTree, printRootedTree, printRootedTreeForHumans, readNode, readRootedTree, readRootedTree, replaceWith, resetNode, rootedTreeEquals, rootedTreeHashCode, rootParent, swapCompatibleWith, toStringForError, toStringForHumans, writeRootedTree
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

P_ADFARGUMENT

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

P_ARGUMENT

public static final java.lang.String P_ARGUMENT
See Also:
Constant Field Values
Constructor Detail

ADFArgument

public ADFArgument()
Method Detail

defaultBase

public Parameter defaultBase()
Description copied from class: GPNode
The default base for GPNodes -- defined even though GPNode is abstract so you don't have to in subclasses.

Specified by:
defaultBase in interface Prototype
Overrides:
defaultBase in class GPNode

setup

public void setup(EvolutionState state,
                  Parameter base)
Description copied from class: GPNode
Sets up a prototypical GPNode with those features all nodes of that prototype share, and nothing more. So no filled-in children, no argposition, no parent. Yet. This must be called after the GPTypes and GPNodeConstraints have been set up. Presently they're set up in GPInitializer, which gets called before this does, so we're safe. You should override this if you need to load some special features on a per-function basis. Note that base hangs off of a function set, so this method may get called for different instances in the same GPNode class if they're being set up as prototypes for different GPFunctionSets. If you absolutely need some global base, then you should use something hanging off of GPDefaults.base(). The ultimate caller of this method must guarantee that he will eventually call state.output.exitIfErrors(), so you can freely use state.output.error instead of state.output.fatal(), which will help a lot.

Specified by:
setup in interface Prototype
Specified by:
setup in interface Setup
Overrides:
setup in class GPNode

toString

public java.lang.String toString()
Description copied from class: GPNode
Returns a Lisp-like atom for the node which can be read in again by computer. If you need to encode an integer or a float or whatever for some reason (perhaps if it's an ERC), you should use the ec.util.Code library.

Specified by:
toString in class GPNode

writeNode

public void writeNode(EvolutionState state,
                      java.io.DataOutput dataOutput)
               throws java.io.IOException
Description copied from class: GPNode
Override this to write any additional node-specific information to dataOutput besides: the number of arguments, the specific node class, the children, and the parent. The default version of this method does nothing.

Overrides:
writeNode in class GPNode
Throws:
java.io.IOException

readNode

public void readNode(EvolutionState state,
                     java.io.DataInput dataInput)
              throws java.io.IOException
Description copied from class: GPNode
Override this to read any additional node-specific information from dataInput besides: the number of arguments, the specific node class, the children, and the parent. The default version of this method does nothing.

Overrides:
readNode in class GPNode
Throws:
java.io.IOException

eval

public void eval(EvolutionState state,
                 int thread,
                 GPData input,
                 ADFStack stack,
                 GPIndividual individual,
                 Problem problem)
Description copied from class: GPNode
Evaluates the node with the given thread, state, individual, problem, and stack. Your random number generator will be state.random[thread]. The node should, as appropriate, evaluate child nodes with these same items passed to eval(...).

About input: input is special; it is how data is passed between parent and child nodes. If children "receive" data from their parent node when it evaluates them, they should receive this data stored in input. If (more likely) the parent "receives" results from its children, it should pass them an input object, which they'll fill out, then it should check this object for the returned value.

A tree is typically evaluated by dropping a GPData into the root. When the root returns, the resultant input should hold the return value.

In general, you should not be creating new GPDatas. If you think about it, in most conditions (excepting ADFs and ADMs) you can use and reuse input for most communications purposes between parents and children.

So, let's say that your GPNode function implements the boolean AND function, and expects its children to return return boolean values (as it does itself). You've implemented your GPData subclass to be, uh, BooleanData, which looks like

public class BooleanData extends GPData 
    {
    public boolean result;
    public GPData copyTo(GPData gpd)
      {
      ((BooleanData)gpd).result = result;
      }
    }

...so, you might implement your eval(...) function as follows:

public void eval(final EvolutionState state,
                     final int thread,
                     final GPData input,
                     final ADFStack stack,
                     final GPIndividual individual,
                     final Problem problem
    {
    BooleanData dat = (BooleanData)input;
    boolean x;

    // evaluate the first child
    children[0].eval(state,thread,input,stack,individual,problem);
  
    // store away its result
    x = dat.result;

    // evaluate the second child
    children[1].eval(state,thread,input,stack,individual,problem);

    // return (in input) the result of the two ANDed

    dat.result = dat.result && x;
    return;
    }
        

Specified by:
eval in class GPNode