de.up.ling.irtg.algebra

Class TreeAlgebra

java.lang.Object

de.up.ling.irtg.algebra.Algebra<Tree<String>>

de.up.ling.irtg.algebra.TreeAlgebra

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

TreeWithAritiesAlgebra

public class TreeAlgebra
extends Algebra<Tree<String>>

The tree algebra. The elements of this algebra are the ranked trees over a given signature. Any string f can be used as a tree-combining operation of an arbitrary arity; the term f(t1,...,tn) evaluates to the tree f(t1,...,tn). Care must be taken that only ranked trees can be described; the parseString method will infer the arity of each symbol f that you use, and will throw an exception if you try to use f with two different arities.

Author:

koller

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
TreeAlgebra()

Method Summary

Modifier and Type	Method and Description
static int	countBrackets(Tree<String> tree) Counts the number of nodes in a tree - minus the number of the leaf nodes.
TreeAutomaton	decompose(Tree<String> value) Computes a decomposition automaton for the given value.
Tree<String>	evaluate(Tree<String> t) Evaluates a term over the algebra's signature into an algebra object.
Class	getClassOfValues() Returns the class of the elements of this algebra.
Tree<String>	parseString(String representation) Resolves the string representation of some element of the algebra's domain to this element.
static double	precision(Tree<String> result, Tree<String> gold) Computes the standard precision measure for two trees.
static double	recall(Tree<String> result, Tree<String> gold) Computes the standard recall measure for two trees.
JComponent	visualize(Tree<String> object) Returns a Swing component that visualizes an object of this algebra.

Methods inherited from class de.up.ling.irtg.algebra.Algebra

getAllAlgebraClasses, getSignature, hasOptions, readOptions, representAsString, setOptions, writeOptions

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TreeAlgebra

public TreeAlgebra()

Method Detail

evaluate

public Tree<String> evaluate(Tree<String> t)

Description copied from class: Algebra

Evaluates a term over the algebra's signature into an algebra object.

Overrides:

evaluate in class Algebra<Tree<String>>

Parameters:

t - a term (= tree whose nodes are labeled with algebra operation symbols)

Returns:

decompose

public TreeAutomaton decompose(Tree<String> value)

Description copied from class: Algebra

Computes a decomposition automaton for the given value. A decomposition automaton is a finite tree automaton which accepts exactly those terms over the algebra's signature which evaluate to the given value.

Overrides:

decompose in class Algebra<Tree<String>>

Returns:

visualize

public JComponent visualize(Tree<String> object)

Description copied from class: Algebra

Returns a Swing component that visualizes an object of this algebra. The default implementation simply returns a JLabel containing a string representation of the algebra object. Override this method to provide more human-readable graphical presentations.

Overrides:

visualize in class Algebra<Tree<String>>

Returns:

parseString

public Tree<String> parseString(String representation)
                         throws ParserException

Description copied from class: Algebra

Resolves the string representation of some element of the algebra's domain to this element. For instance, the method parseString(java.lang.String) resolves the string "f(a,b)" into a tree with three nodes.

It is the job of an algebra class to keep track of the signature of the algebra. Many algebras have a potentially infinite domain (e.g. the string algebra can be used with arbitrary alphabets), so the algebra class should keep track of the symbols that were actually used in the current run of the program. The best practice is to update the signature each time the parseString method is called. The rest of the IRTG tool code takes care to call parseString of the respective algebra to obtain objects of type E, so this ensures that the signature is always up-to-date.

Specified by:

parseString in class Algebra<Tree<String>>

Returns:

Throws:

ParserException

getClassOfValues

public Class getClassOfValues()

Description copied from class: Algebra

Returns the class of the elements of this algebra. The default interpretation simply returns Object; you may override this with the actual class of the objects of your algebra.

This method is used in some places throughout Alto to figure out what OutputCodecs are appropriate for encoding objects of the algebra. By overriding the method to return more specific classes than Object, you make more output codecs available in those places.

Overrides:

getClassOfValues in class Algebra<Tree<String>>

Returns:

countBrackets

public static int countBrackets(Tree<String> tree)

Counts the number of nodes in a tree - minus the number of the leaf nodes.

Parameters:

tree -

Returns:

recall

public static double recall(Tree<String> result,
                            Tree<String> gold)

Computes the standard recall measure for two trees.

Parameters:

result -

gold -

Returns:

precision

public static double precision(Tree<String> result,
                               Tree<String> gold)

Computes the standard precision measure for two trees.

Parameters:

result -

gold -

Returns: