org.chocosolver.solver.explanations

Class RuleStore

java.lang.Object

org.chocosolver.solver.explanations.RuleStore

public class RuleStore
extends Object

A RuleStore is a central object in the Asynchronous, Reverse, Low-Intrusive and Lazy explanation engine. It stores a set of rules which enables to compute the explanation of a situation (for instance a conflict) by scanning the events generated on the current branch. The set of rules is dynamically maintained.

Created by cprudhom on 09/12/14. Project: choco.

Constructor Summary

Constructors

Constructor and Description
RuleStore(Solver solver, boolean saveCauses, boolean enablePartialExplanation) Instantiate a rule store to compute explanations

Method Summary

Methods

Modifier and Type	Method and Description
boolean	addBoundsRule(IntVar var) Add an upper bound rule and a lower bound rule, that is, any event on the upper bound or the lower bound of the variable needs to be retained
boolean	addFullDomainRule(IntVar var) Add a full domain rule, that is, any events involving the variable needs to be retained.
boolean	addLowerBoundRule(IntVar var) Add a lower bound rule, that is, any event on the lower bound of the variable needs to be retained
boolean	addPropagatorActivationRule(Propagator propagator) Add a propagator activation rule
boolean	addRemovalRule(IntVar var, int value) Add a value removal rule, that is, the event which remove the value needs to be retained.
void	addRules(Rules someRules) Update the current rules with the one in 'rules'
boolean	addUpperBoundRule(IntVar var) Add a upper bound rule, that is, any event on the upper bound of the variable needs to be retained
Explanation	getDecisionRefutation(Decision decision) Get the explanation associated with a decision refutation
int	getMask(Variable var) Return the current rule mask associated to the variable vid
Rules	getRules() Return the current rules, for copy only.
void	init() Initialize the rulestore for a new explanation
boolean	isPreemptedStop() when conditions are favorable, a preempted stop can be considered: not all events have to be analyzed.
boolean	match(int idx, IEventStore eventStore) Return true if the event represented by matches one of the active rules.
boolean	matchDomain(int ruleMask, IntVar ivar, IntEventType evt, int i1, int i2, int i3) Check whether a variable domain matches a rule
void	moveDecisionRefutation(Decision decision, int to) Move a decision refutation to the 'to' index
void	setRules(Rules someRules) Replace the rules by a new one.
void	storeDecisionRefutation(Decision decision, Explanation explanation) Store a decision refutation, for future reasoning.
void	update(int idx, IEventStore eventStore, Explanation explanation) Update the rule store, and the explanation, wrt a given event

Methods inherited from class java.lang.Object

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

Constructor Detail

RuleStore

public RuleStore(Solver solver,
         boolean saveCauses,
         boolean enablePartialExplanation)

Instantiate a rule store to compute explanations

Parameters:

solver - the solver to observe

saveCauses - does it keep trace of the constraints in conflict ?

enablePartialExplanation - do explanations need to be complete (for DBT or nogood extraction) ?

Method Detail

init

public void init()

Initialize the rulestore for a new explanation

isPreemptedStop

public boolean isPreemptedStop()

when conditions are favorable, a preempted stop can be considered: not all events have to be analyzed.

match

public boolean match(int idx,
            IEventStore eventStore)

Return true if the event represented by matches one of the active rules.

Parameters:

idx - index in eventStore of the event to evaluate

eventStore - set of events

Throws:

SolverException - when the type of the variable is neither Variable.BOOL or Variable.INT.

matchDomain

public boolean matchDomain(int ruleMask,
                  IntVar ivar,
                  IntEventType evt,
                  int i1,
                  int i2,
                  int i3)

Check whether a variable domain matches a rule

Parameters:

ruleMask - the current rule mask

ivar - the integer variable

evt - the event

i1 - either instantiated value (IN) or new lb (LB) or new ub (UB) or removed value (RM)

i2 - either old lb (IN, LB) or old ub (UB) or -1 (RM)

i3 - either old ub (IN), or -1 (LB, UB, RM)

update

public void update(int idx,
          IEventStore eventStore,
          Explanation explanation)

Update the rule store, and the explanation, wrt a given event

Parameters:

idx - index of the event

eventStore - the event store

explanation - the explanation to compute

addRules

public void addRules(Rules someRules)

Update the current rules with the one in 'rules'

Parameters:

someRules - some rules

getRules

public Rules getRules()

Return the current rules, for copy only.

Returns:

a set of rules

setRules

public void setRules(Rules someRules)

Replace the rules by a new one. This should be done carefully since the set of rules are cleared on each contradiction.

addRemovalRule

public boolean addRemovalRule(IntVar var,
                     int value)

Add a value removal rule, that is, the event which remove the value needs to be retained.

Parameters:

var - the variable to add rule on

value - the removed value

Returns:

true if a new rule has been added (false = already existing rule)

Throws:

SolverException - when the domain is not enumerated

addFullDomainRule

public boolean addFullDomainRule(IntVar var)

Add a full domain rule, that is, any events involving the variable needs to be retained.

Parameters:

var - the variable to add rule on

Returns:

true if a new rule has been added (false = already existing rule)

addLowerBoundRule

public boolean addLowerBoundRule(IntVar var)

Add a lower bound rule, that is, any event on the lower bound of the variable needs to be retained

Parameters:

var - the variable to add rule on

Returns:

true if a new rule has been added (false = already existing rule)

addUpperBoundRule

public boolean addUpperBoundRule(IntVar var)

Add a upper bound rule, that is, any event on the upper bound of the variable needs to be retained

Parameters:

var - the variable to add rule on

Returns:

true if a new rule has been added (false = already existing rule)

addBoundsRule

public boolean addBoundsRule(IntVar var)

Add an upper bound rule and a lower bound rule, that is, any event on the upper bound or the lower bound of the variable needs to be retained

Parameters:

var - the variable to add rule on

Returns:

true if a new rule has been added (false = already existing rule)

getMask

public int getMask(Variable var)

Return the current rule mask associated to the variable vid

Parameters:

var - a variable

Returns:

the current mask or NO_ENTRY

addPropagatorActivationRule

public boolean addPropagatorActivationRule(Propagator propagator)

Add a propagator activation rule

Parameters:

propagator - activated propagator

Returns:

true if a new rule has been adde

storeDecisionRefutation

public void storeDecisionRefutation(Decision decision,
                           Explanation explanation)

Store a decision refutation, for future reasoning.

Parameters:

decision - refuted decision

explanation - the explanation of the refutation

moveDecisionRefutation

public void moveDecisionRefutation(Decision decision,
                          int to)

Move a decision refutation to the 'to' index

Parameters:

decision - a refuted decision

to - the new index

getDecisionRefutation

public Explanation getDecisionRefutation(Decision decision)

Get the explanation associated with a decision refutation

Parameters:

decision - a RIGHT branch decision

Returns:

an explanation