Package ec.gp

Class ADFArgument

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

See Also:

  • Field Details

  • Constructor Details

    • ADFArgument

      public ADFArgument()

  • Method Details

    • name

      public String name()
      Description copied from class: GPNode
      Returns a Lisp-like atom for the node and any nodes of the same class. This will almost always be identical to the result of toString() (and the default does exactly this), but for ERCs it'll be different: toString will include the encoded constant data, whereas name() will not include this information and will be the same for all ERCs of this type. If two nodes are nodeEquivalentTo(...) each other, then they will have the same name(). If two nodes are nodeEquals(...) each other, then they will have the same toString().
      Overrides:
      name in class GPNode

    • expectedChildren

      public int expectedChildren()
      Description copied from class: GPNode
      Returns the number of children this node expects to have. This method is only called by the default implementation of checkConstraints(...), and by default it returns CHILDREN_UNKNOWN. You can override this method to return a value >= 0, which will be checked for in the default checkConstraints(...), or you can leave this method alone and override checkConstraints(...) to check for more complex constraints as you see fit.
      Overrides:
      expectedChildren in class GPNode

    • 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

    • toString

      public 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

    • 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

    • writeNode

      public void writeNode(EvolutionState state, DataOutput dataOutput) throws 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:
      IOException

    • readNode

      public void readNode(EvolutionState state, DataInput dataInput) throws 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:
      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 invalid input: '&'invalid input: '&' x;
    return;
    }
      Specified by:
      eval in class GPNode