org.uacalc.alg

Class Subalgebra

java.lang.Object

org.uacalc.alg.GeneralAlgebra

org.uacalc.alg.Subalgebra

All Implemented Interfaces:

Algebra, SmallAlgebra

public class Subalgebra
extends GeneralAlgebra
implements SmallAlgebra

This class represents a subalgebra of a SmallAlgebra.

Version:

$Id$

Author:

Ralph Freese

Nested Class Summary

Nested classes/interfaces inherited from interface org.uacalc.alg.SmallAlgebra

SmallAlgebra.AlgebraType

Field Summary

Fields

Modifier and Type	Field and Description
protected SmallAlgebra	superAlgebra
protected int[]	univArray

Fields inherited from class org.uacalc.alg.GeneralAlgebra

con, description, monitor, name, operationsMap, similarityType, size, sub, universe

Fields inherited from interface org.uacalc.alg.Algebra

CARDINALITY_COUNTABLE, CARDINALITY_COUNTABLY_INFINITE, CARDINALITY_FINITE, CARDINALITY_INFINITE, CARDINALITY_UNKNOWN

Constructor Summary

Constructors

Constructor and Description
Subalgebra(SmallAlgebra alg, int[] univ)
Subalgebra(SmallAlgebra alg, IntArray univ)
Subalgebra(java.lang.String name, SmallAlgebra alg, int[] univ) Form the subalgebra given the super algebra and the subuniverse.
Subalgebra(java.lang.String name, SmallAlgebra alg, IntArray univ)

Method Summary

Modifier and Type	Method and Description
SmallAlgebra.AlgebraType	algebraType() The type of algebra this is, like a quotient algebra.
CongruenceLattice	con() The congurence lattice.
static SmallAlgebra	congruenceAsAlgebra(SmallAlgebra alg, Partition cong) This gives the congruence cong as a subalgebra of A^2.
static SmallAlgebra	congruenceAsAlgebra(java.lang.String name, SmallAlgebra alg, Partition cong) This gives the congruence cong as a subalgebra of A^2.
void	convertToDefaultValueOps() This is used in the UI.
int	elementIndex(java.lang.Object obj) This method will return k if elem is the kth element; otherwise -1.
java.lang.Object	getElement(int index) returns the kth element.
int[]	getSubuniverseArray() Get the subuniverse of the super algebra for this algebra.
java.util.List	getUniverseList() The universe as a List such getElement(k) will equal the kth element of the List.
java.util.Map	getUniverseOrder() A map that can be used for elementIndex(a).
int	index(int k) Find the index in this subalgebra of the element with index k in the super algebra.
static void	main(java.lang.String[] args)
void	makeOperationTables() Make operation tables to speed up the evaluation of operations at the cost using more space.
protected java.util.Set	makeUniverse()
BasicPartition	restrictPartition(Partition par) Restrict a partition (or congruence) on the parent algebra to this subalgebra.
SubalgebraLattice	sub() The subalgebra lattice.
SmallAlgebra	superAlgebra()
java.util.Set	universe() We use java.util.Set to hold the universe of the algebra.

Methods inherited from class org.uacalc.alg.GeneralAlgebra

cardinality, constantOperations, getDescription, getMonitor, getName, getOperation, getOperationsMap, inputSize, isIdempotent, isSimilarTo, isTotal, isUnary, iterator, monitoring, operations, parent, parents, resetConAndSub, setDescription, setMonitor, setName, setOperations, setUniverse, similarityType, updateSimilarityType

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.uacalc.alg.SmallAlgebra

parent, parents, resetConAndSub

Methods inherited from interface org.uacalc.alg.Algebra

cardinality, constantOperations, getDescription, getMonitor, getName, getOperation, getOperationsMap, inputSize, isIdempotent, isSimilarTo, isTotal, isUnary, iterator, monitoring, operations, setDescription, setMonitor, setName, similarityType, updateSimilarityType

Field Detail

superAlgebra

protected final SmallAlgebra superAlgebra

univArray

protected final int[] univArray

Constructor Detail

Subalgebra

public Subalgebra(SmallAlgebra alg,
                  int[] univ)

Subalgebra

public Subalgebra(SmallAlgebra alg,
                  IntArray univ)

Subalgebra

public Subalgebra(java.lang.String name,
                  SmallAlgebra alg,
                  IntArray univ)

Subalgebra

public Subalgebra(java.lang.String name,
                  SmallAlgebra alg,
                  int[] univ)

Form the subalgebra given the super algebra and the subuniverse.

Method Detail

index

public int index(int k)

Find the index in this subalgebra of the element with index k in the super algebra. If k is not in the subalgebra, a negative number is returned.

restrictPartition

public BasicPartition restrictPartition(Partition par)

Restrict a partition (or congruence) on the parent algebra to this subalgebra.

makeOperationTables

public void makeOperationTables()

Description copied from interface: Algebra

Make operation tables to speed up the evaluation of operations at the cost using more space.

Specified by:

makeOperationTables in interface Algebra

Overrides:

makeOperationTables in class GeneralAlgebra

See Also:

Operation.makeTable

superAlgebra

public SmallAlgebra superAlgebra()

getSubuniverseArray

public int[] getSubuniverseArray()

Get the subuniverse of the super algebra for this algebra.

con

public CongruenceLattice con()

Description copied from interface: SmallAlgebra

The congurence lattice.

Specified by:

con in interface SmallAlgebra

Overrides:

con in class GeneralAlgebra

sub

public SubalgebraLattice sub()

Description copied from interface: SmallAlgebra

The subalgebra lattice.

Specified by:

sub in interface SmallAlgebra

Overrides:

sub in class GeneralAlgebra

elementIndex

public int elementIndex(java.lang.Object obj)

Description copied from interface: SmallAlgebra

This method will return k if elem is the kth element; otherwise -1. (Should we have it throw an error instead?)

Specified by:

elementIndex in interface SmallAlgebra

getElement

public java.lang.Object getElement(int index)

Description copied from interface: SmallAlgebra

returns the kth element.

Specified by:

getElement in interface SmallAlgebra

getUniverseList

public java.util.List getUniverseList()

Description copied from interface: SmallAlgebra

The universe as a List such getElement(k) will equal the kth element of the List. It is allowed to be null.

Specified by:

getUniverseList in interface SmallAlgebra

getUniverseOrder

public java.util.Map getUniverseOrder()

Description copied from interface: SmallAlgebra

A map that can be used for elementIndex(a). It is allowed to be null.

Specified by:

getUniverseOrder in interface SmallAlgebra

universe

public java.util.Set universe()

Description copied from interface: Algebra

We use java.util.Set to hold the universe of the algebra. In order to accomodate infinite algebras and algebras with unknown cardinality, we allow the following changes:

• size can return a negative value if the cardinality is infinite or unknown or is larger that the largest int. In this case we may want to specify some information about the cardinality in another method but we have not decided on this yet.
• it is allowed that the iterator method of Set throw an UnsupportedOperationException.
• when extending AbstractSet, the contains method should be overwritten.

Specified by:

universe in interface Algebra

Overrides:

universe in class GeneralAlgebra

makeUniverse

protected java.util.Set makeUniverse()

congruenceAsAlgebra

public static SmallAlgebra congruenceAsAlgebra(SmallAlgebra alg,
                                               Partition cong)

This gives the congruence cong as a subalgebra of A^2.

congruenceAsAlgebra

public static SmallAlgebra congruenceAsAlgebra(java.lang.String name,
                                               SmallAlgebra alg,
                                               Partition cong)

This gives the congruence cong as a subalgebra of A^2.

convertToDefaultValueOps

public void convertToDefaultValueOps()

Description copied from interface: SmallAlgebra

This is used in the UI. Only valid for BASIC algebras.

Specified by:

convertToDefaultValueOps in interface SmallAlgebra

algebraType

public SmallAlgebra.AlgebraType algebraType()

Description copied from interface: SmallAlgebra

The type of algebra this is, like a quotient algebra.

Specified by:

algebraType in interface SmallAlgebra

Returns:

main

public static void main(java.lang.String[] args)
                 throws java.io.IOException,
                        BadAlgebraFileException

Throws:

java.io.IOException

BadAlgebraFileException