org.dllearner.refinementoperators
Class MathOperations

java.lang.Object
  org.dllearner.refinementoperators.MathOperations

public class MathOperations
extends Object

Math operations related to refinement operators.

Author:

Jens Lehmann

Constructor Summary

MathOperations()

Method Summary

static boolean	containsDoubleObjectSomeRestriction(Description d) Returns true if the same property is used twice in an object some restriction, e.g.
static List<List<Integer>>	getCombos(int number) Given number, the functions returns all combinations of natural numbers plus the number count (which can be thought of as the number of interconnecting symbols between those numbers) adds up to number.
static List<List<Integer>>	getCombos(int length, int maxValue) Methods for computing combinations with the additional restriction that maxValue is the highest natural number, which can occur.
static SortedSet<Union>	incCrossProduct(Set<Union> baseSet, Set<Description> newSet) Implements a cross product in the sense that each union description in the base set is extended by each description in the new set.

Methods inherited from class java.lang.Object

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

Constructor Detail

MathOperations

public MathOperations()

Method Detail

getCombos

public static List<List<Integer>> getCombos(int number)

Given number, the functions returns all combinations of natural numbers plus the number count (which can be thought of as the number of interconnecting symbols between those numbers) adds up to number. It uses an efficient algorithm to achieve this, which can handle number=50 in less than a second and number=30 in about 10 milliseconds on an average PC. For illustrating the function, the return values of the first numbers are given: number = 1: [[1]] number = 2: [[2]] number = 3: [[3], [1, 1]] number = 4: [[4], [2, 1]] number = 5: [[5], [3, 1], [2, 2], [1, 1, 1]] number = 6: [[6], [4, 1], [3, 2], [2, 1, 1]] number = 7: [[7], [5, 1], [4, 2], [3, 3], [3, 1, 1], [2, 2, 1], [1, 1, 1, 1]]

Parameters:

number - A natural number.

Returns:

A two dimensional list constructed as described above.

getCombos

public static List<List<Integer>> getCombos(int length,
                                            int maxValue)

Methods for computing combinations with the additional restriction that maxValue is the highest natural number, which can occur.

Parameters:

length - Length of construct.

maxValue - Maximum value which can occur in sum.

Returns:

A two dimensional list constructed in getCombos(int).

See Also:

getCombos(int)

incCrossProduct

public static SortedSet<Union> incCrossProduct(Set<Union> baseSet,
                                               Set<Description> newSet)

Implements a cross product in the sense that each union description in the base set is extended by each description in the new set. Example: baseSet = {A1 OR A2, A1 or A3} newSet = {A1, EXISTS r.A3} Returns: {A1 OR A2 OR A1, A1 OR A2 OR EXISTS r.A3, A1 OR A3 OR A1, A1 OR A3 OR EXISTS r.A3} If the base set is empty, then the return value are union class descriptions for each value in newSet (a union with only one concept).

Parameters:

baseSet - A set of union class descriptions.

newSet - The descriptions to add to each union class descriptions.

Returns:

The "cross product" of baseSet and newSet.

containsDoubleObjectSomeRestriction

public static boolean containsDoubleObjectSomeRestriction(Description d)

Returns true if the same property is used twice in an object some restriction, e.g. (EXISTS r.A1 AND A2 AND EXISTS r.A3) returns true, while (A1 OR A2) and (EXISTS r.A1 AND A2 AND EXISTS s.A3) return false. Note that the method does not work recursively, e.g. it return false for EXISTS r.(EXISTS r.A1 AND A2 AND EXISTS r.A3).

Parameters:

d - Description to test.

Returns:

See description.