JaCoP.search
Class SplitSelect<T extends IntVar>

java.lang.Object
  JaCoP.search.SimpleSelect<T>
      JaCoP.search.SplitSelect<T>

Type Parameters:

T - type of variable being used in the search.

All Implemented Interfaces:

SelectChoicePoint<T>

public class SplitSelect<T extends IntVar>
extends SimpleSelect<T>

It is simple and customizable selector of decisions (constraints) which will be enforced by search. However, it does not use X=c as a search decision but rather X <= c (potentially splitting the domain), unless c is equal to the maximal value in the domain of X then the constraint X < c is used.

Version:

3.1

Author:

Radoslaw Szymanek and Krzysztof Kuchcinski

Field Summary

boolean

leftFirst It specifies if the left branch (values smaller or equal to the value selected) are first considered.

Fields inherited from class JaCoP.search.SimpleSelect

inputOrderTieBreaking, position

Constructor Summary

SplitSelect(T[] variables, ComparatorVariable<T> varSelect, ComparatorVariable<T> tieBreakerVarSelect, Indomain<T> indomain)
It constructs a simple selection mechanism for choice points.

SplitSelect(T[] variables, ComparatorVariable<T> varSelect, Indomain<T> indomain)
The constructor to create a simple choice select mechanism.

Method Summary

PrimitiveConstraint	getChoiceConstraint(int index) It always returns null as choice point is obtained by getChoiceVariable and getChoiceValue.
T	getChoiceVariable(int index) It returns the variable which is the base on the next choice point.

Methods inherited from class JaCoP.search.SimpleSelect

getChoiceValue, getIndex, getVariablesMapping, placeSearchVariable, toString

Methods inherited from class java.lang.Object

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

Field Detail

leftFirst

public boolean leftFirst

It specifies if the left branch (values smaller or equal to the value selected) are first considered.

Constructor Detail

SplitSelect

public SplitSelect(T[] variables,
                   ComparatorVariable<T> varSelect,
                   Indomain<T> indomain)

The constructor to create a simple choice select mechanism.

Parameters:

variables - variables upon which the choice points are created.

varSelect - the variable comparator to choose the variable.

indomain - the value heuristic to choose a value for a given variable.

SplitSelect

public SplitSelect(T[] variables,
                   ComparatorVariable<T> varSelect,
                   ComparatorVariable<T> tieBreakerVarSelect,
                   Indomain<T> indomain)

It constructs a simple selection mechanism for choice points.

Parameters:

variables - variables used as basis of the choice point.

varSelect - the main variable comparator.

tieBreakerVarSelect - secondary variable comparator employed if the first one gives the same metric.

indomain - the heuristic to choose value assigned to a chosen variable.

Method Detail

getChoiceVariable

public T getChoiceVariable(int index)

Description copied from class: SimpleSelect

It returns the variable which is the base on the next choice point. Only if choice is of an X = C type. This function returns null if all variables have a value assigned or a choice point based on other type of constraint is being selected. The parameter index is the last value which have been return by this SelectChoicePoint object which has not been backtracked upon yet.

Specified by:

getChoiceVariable in interface SelectChoicePoint<T extends IntVar>

Overrides:

getChoiceVariable in class SimpleSelect<T extends IntVar>

Parameters:

index - the position of the last variable in selection choice point heuristic.

Returns:

variable based on which the choice needs to be created.

getChoiceConstraint

public PrimitiveConstraint getChoiceConstraint(int index)

Description copied from class: SimpleSelect

It always returns null as choice point is obtained by getChoiceVariable and getChoiceValue.

Specified by:

getChoiceConstraint in interface SelectChoicePoint<T extends IntVar>

Overrides:

getChoiceConstraint in class SimpleSelect<T extends IntVar>

Parameters:

index - the position of the last variable returned by selection choice point heuristic.

Returns:

primitive constraint which is a base of a choice point.