de.up.ling.irtg.algebra

Class SetAlgebra

java.lang.Object

de.up.ling.irtg.algebra.Algebra<Set<List<String>>>

de.up.ling.irtg.algebra.SetAlgebra

All Implemented Interfaces:

Serializable

public class SetAlgebra
extends Algebra<Set<List<String>>>

An algebra of sets. The elements of this algebra are relations (of arbitrary arity) over some given universe. The algebra interprets the following operations:

• project_i(R) projects its argument R (a k-place relation with k >= i) to the set of i-th elements of this relation.
• intersect_i(R,F) returns the set of all tuples of R (a k-place relation with k >= i) whose i-th element is a member of F (a subset of the universe).
• uniq_a(A) returns the set A (a subset of the universe) itself if A = {a}; otherwise it returns the empty set.
• member_a(A) returns the set {{a}} if {a} belongs to A; otherwise it returns the empty set.
• T returns the universe.

Importantly, the decomposition automata for this algebra only implement TreeAutomaton.getRulesBottomUp(int, int[]), not TreeAutomaton.getRulesTopDown(int, int). This means that you need to take care to only ever call methods on them that look at rules bottom-up.

Author:

koller

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SetAlgebra.NoModelException

Constructor Summary

Constructors

Constructor and Description
SetAlgebra() Creates a new instance with a new model and signature.
SetAlgebra(Map<String,Set<List<String>>> atomicInterpretations) Creates a new instance with a new signature and model, which adds the given atomicInterpretations to the model.

Method Summary

Modifier and Type	Method and Description
TreeAutomaton	decompose(Set<List<String>> value) Computes a decomposition automaton for the given value.
Map<String,Set<List<String>>>	getAtomicInterpretations()
boolean	hasOptions() Returns true if the algebra implementation has options that would make sense to be set using Algebra.setOptions(java.lang.String).
Set<List<String>>	parseString(String representation) Resolves the string representation of some element of the algebra's domain to this element.
void	readOptions(Reader optionReader) Reads the options from a Json string representation.
void	setAtomicInterpretations(Map<String,Set<List<String>>> atomicInterpretations)
void	writeOptions(Writer optionWriter) Writes the interpretations of the atomic concepts to the given Writer.

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

evaluate, getAllAlgebraClasses, getClassOfValues, getSignature, representAsString, setOptions, visualize

Methods inherited from class java.lang.Object

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

Constructor Detail

SetAlgebra

public SetAlgebra()

Creates a new instance with a new model and signature.

SetAlgebra

public SetAlgebra(Map<String,Set<List<String>>> atomicInterpretations)

Creates a new instance with a new signature and model, which adds the given atomicInterpretations to the model.

Parameters:

atomicInterpretations -

Method Detail

hasOptions

public boolean hasOptions()

Description copied from class: Algebra

Returns true if the algebra implementation has options that would make sense to be set using Algebra.setOptions(java.lang.String).

Overrides:

hasOptions in class Algebra<Set<List<String>>>

Returns:

writeOptions

public void writeOptions(Writer optionWriter)
                  throws Exception

Writes the interpretations of the atomic concepts to the given Writer. This method should encode into a Json string, but is not yet implemented.

Overrides:

writeOptions in class Algebra<Set<List<String>>>

Parameters:

optionWriter -

Throws:

Exception

See Also:

readOptions(java.io.Reader)

decompose

public TreeAutomaton decompose(Set<List<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<Set<List<String>>>

Returns:

readOptions

public void readOptions(Reader optionReader)
                 throws Exception

Reads the options from a Json string representation. The options for the SetAlgebra consist in a specification of the universe and the interpretations of the atomic concepts. For instance, the following string says that "sleep" is a binary relation with the single element (e,r1), whereas "rabbit" is a unary relation containing the elements r1 and r2.

{"sleep": [["e", "r1"]], "rabbit": [["r1"], ["r2"]], "white": [["r1"], ["b"]], "in": [["r1","h"], ["f","h2"]], "hat": [["h"], ["h2"]] }

Overrides:

readOptions in class Algebra<Set<List<String>>>

Parameters:

optionReader -

Throws:

Exception

setAtomicInterpretations

public final void setAtomicInterpretations(Map<String,Set<List<String>>> atomicInterpretations)

getAtomicInterpretations

public Map<String,Set<List<String>>> getAtomicInterpretations()

Returns:

the atomicInterpretations

parseString

public Set<List<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 TreeAlgebra.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<Set<List<String>>>

Returns:

Throws:

ParserException