ec.gp
Class ADM

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

public class ADM
extends ADF

An ADM is an ADF which doesn't evaluate its arguments beforehand, but instead only evaluates them (and possibly repeatedly) when necessary at runtime. For more information, see ec.gp.ADF.

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

Field Summary
 
Fields inherited from class ec.gp.ADF
associatedTree, functionName, P_ADF, P_ASSOCIATEDTREE, P_FUNCTIONNAME
 
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
ADM()
           
 
Method Summary
 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.
 java.lang.String toString()
          Returns a Lisp-like atom for the node which can be read in again by computer.
 
Methods inherited from class ec.gp.ADF
checkConstraints, defaultBase, nodeEquals, nodeHashCode, readNode, setup, writeNode
 
Methods inherited from class ec.gp.GPNode
atDepth, clone, cloneReplacing, cloneReplacing, cloneReplacing, cloneReplacingAtomic, cloneReplacingAtomic, cloneReplacingNoSubclone, constraints, contains, depth, errorInfo, lightClone, makeCTree, makeLatexTree, nodeEquivalentTo, 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
 

Constructor Detail

ADM

public ADM()
Method Detail

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.

Overrides:
toString in class ADF

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;
    }
        

Overrides:
eval in class ADF