org.jacop.constraints.regular

Class Regular

java.lang.Object

org.jacop.constraints.DecomposedConstraint<Constraint>

org.jacop.constraints.Constraint

org.jacop.constraints.regular.Regular

All Implemented Interfaces:

RemoveLevelLate, Stateful, UsesQueueVariable

public class Regular
extends Constraint
implements UsesQueueVariable, Stateful, RemoveLevelLate

Regular constraint accepts only the assignment to variables which is accepted by an automaton. This constraint implements a polynomial algorithm to establish GAC. There are number of improvements (iterative execution, optimization of computational load upon backtracking) to improve the constraint further.

Version:

4.9

Author:

Polina Makeeva and Radoslaw Szymanek

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	debugAll It specifies if debugging information should be printed out.
Map<Integer,String>	dNames dNames contain a "name" for each value from the union of all variabl's domains.
FSM	fsm It specifies finite state machine used by this regular.
String	latexFile Name of the file to store the latex output after consistency call The output will be : file_name + "call number" + ".tex"
IntVar[]	list Array of the variables of the graph levels.
boolean	listRepresentation It specifies if the edges should have a list of values associated with them.
boolean	oneSupport It specifies if the support functionality should be used.
boolean	optimizedMDD It specifies if the translation of FSM into optimized MDD should take place so minimal layered graph can be obtained.
static boolean	saveAllToLatex It specifies if constraint description should be saved to latex for later viewing.
Map<Integer,RegEdge>[]	supports It keeps for each variable value pair a current support.

Fields inherited from class org.jacop.constraints.Constraint

atomicExecution, consistencyPruningEvents, constraintScope, earlyTerminationOK, increaseWeight, numberId, scope, trace

Fields inherited from class org.jacop.constraints.DecomposedConstraint

queueIndex

Constructor Summary

Constructors

Constructor and Description
Regular(FSM fsm, IntVar[] list) Constructor need Store to initialize the time-stamps.

Method Summary

Modifier and Type	Method and Description
void	consistency(Store store) It is a (most probably incomplete) consistency function which removes the values from variables domains.
List<Constraint>	decompose(Store store) It returns an array list of constraint which are used to decompose this constraint.
void	disableState(int level, int pos) It marks state as being not active.
int	getDefaultConsistencyPruningEvent()
RegState	getState(int level, int id) Find the state with the corresponding id.
void	impose(Store store) It imposes the constraint in a given store.
void	imposeDecomposition(Store store) It imposes the decomposition of the given constraint in a given store.
void	pruneArc(int varIndex) Collects the damaged states, after pruning the domain of variable "var", and put these states in two separated sets.
void	queueVariable(int level, Var var) This is a function called to indicate which variable in a scope of constraint has changed.
void	removeLevel(int level) This function is called in case of the backtrack, so a constraint can clear the queue of changed variables which is no longer valid.
void	removeLevelLate(int level) Sweep the graph upon backtracking.
void	saveLatexToFile(String desc) It saves the constraint latex description into file.
void	setLatexBaseFileName(String filename) It sets the filename for the file which is used to save latex descriptions.
String	toLatex(String addDescription) It creates a latex description of the constraint state.
String	toString() It produces a string representation of a constraint state.
int	unreachBackwardLoop(int sucPrevLimit, int level) It does backward check to remove inactive edges and states.
void	unreachForwardLoop(int end, int level) Forward part deletes the outgoing edges of the damaged state and watch whether the successors are still active (in-degree > 0 ), otherwise we collect it and continue the loop.
void	uppendToLatexFile(String desc, String fileName) It appends latex description of the constraint current state to the specified filename.

Methods inherited from class org.jacop.constraints.Constraint

afc, arguments, cleanAfterFailure, getConsistencyPruningEvent, getGuideConstraint, getGuideValue, getGuideVariable, grounded, grounded, id, impose, increaseWeight, intArrayToString, long2int, numberArgs, removeConstraint, requiresMonotonicity, setConsistencyPruningEvent, setConstraintScope, setScope, setScope, setScope, setScope, setScope, setWatchedVariableGrounded, supplyGuideFeedback, updateAFC, watchedVariableGrounded

Methods inherited from class org.jacop.constraints.DecomposedConstraint

auxiliaryVariables, checkInput, checkInput, checkInputForDuplication, checkInputForDuplicationSkipSingletons, checkInputForNullness, checkInputForNullness, checkInputForNullness, derivative, getDubletonsSkipSingletons, imposeDecomposition

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jacop.api.Stateful

isStateful

Field Detail

debugAll

public static final boolean debugAll

It specifies if debugging information should be printed out.

See Also:

Constant Field Values

saveAllToLatex

public static final boolean saveAllToLatex

It specifies if constraint description should be saved to latex for later viewing.

See Also:

Constant Field Values

optimizedMDD

public final boolean optimizedMDD

It specifies if the translation of FSM into optimized MDD should take place so minimal layered graph can be obtained. This option most of the time causes out of memory exception as it requires finding and storing all solutions in mtrie before translation to an optimized MDD can take place. FSM also has to be a deterministic one.

See Also:

Constant Field Values

latexFile

public String latexFile

Name of the file to store the latex output after consistency call The output will be : file_name + "call number" + ".tex"

dNames

public Map<Integer,String> dNames

dNames contain a "name" for each value from the union of all variabl's domains. If Hashmap - dNames - is not null then upon saving the latex graph the values on the edges will be replaced with their "names".

supports

public Map<Integer,RegEdge>[] supports

It keeps for each variable value pair a current support.

listRepresentation

public boolean listRepresentation

It specifies if the edges should have a list of values associated with them.

oneSupport

public boolean oneSupport

It specifies if the support functionality should be used.

fsm

public FSM fsm

It specifies finite state machine used by this regular.

list

public IntVar[] list

Array of the variables of the graph levels.

Constructor Detail

Regular

public Regular(FSM fsm,
               IntVar[] list)

Constructor need Store to initialize the time-stamps.

Parameters:

fsm - (deterministic) finite automaton

list - variables which values have to be accepted by the automaton.

Method Detail

getState

public RegState getState(int level,
                         int id)

Find the state with the corresponding id.

Parameters:

level - specifies the variable for which the state is seeked for.

id - specifies the id of the state.

Returns:

the state at given level with a given id.

pruneArc

public void pruneArc(int varIndex)

Collects the damaged states, after pruning the domain of variable "var", and put these states in two separated sets.

One with the states with zero incoming degree - these are the candidates for the forward part. The other set consists of states with zero out-coming degree - these are the candidates for backward part.

Parameters:

varIndex - the index of the variable which have changed.

unreachBackwardLoop

public int unreachBackwardLoop(int sucPrevLimit,
                               int level)

It does backward check to remove inactive edges and states.

Parameters:

sucPrevLimit - previous number of states at a given level.

level - level for which the backward sweep is computed.

Returns:

level at which the sweep has ended. TODO return value is not used.

unreachForwardLoop

public void unreachForwardLoop(int end,
                               int level)

Forward part deletes the outgoing edges of the damaged state and watch whether the successors are still active (in-degree > 0 ), otherwise we collect it and continue the loop. TODO return value is not used.

Parameters:

end - the position of the last active state at a given level.

level - level being examined.

disableState

public void disableState(int level,
                         int pos)

It marks state as being not active.

Parameters:

level - level at which the state is residing.

pos - position of the state in the array of states.

removeLevel

public void removeLevel(int level)

Description copied from interface: Stateful

This function is called in case of the backtrack, so a constraint can clear the queue of changed variables which is no longer valid. This function is called *before* all timestamps, variables, mutablevariables have reverted to their previous value.

Specified by:

removeLevel in interface Stateful

Parameters:

level - the level which is being removed.

removeLevelLate

public void removeLevelLate(int level)

Sweep the graph upon backtracking.

Specified by:

removeLevelLate in interface RemoveLevelLate

Parameters:

level - the level which is being removed.

queueVariable

public void queueVariable(int level,
                          Var var)

Description copied from class: Constraint

This is a function called to indicate which variable in a scope of constraint has changed. It also indicates a store level at which the change has occurred.

Overrides:

queueVariable in class Constraint

Parameters:

level - the level of the store at which the change has occurred.

var - variable which has changed.

consistency

public void consistency(Store store)

Description copied from class: Constraint

It is a (most probably incomplete) consistency function which removes the values from variables domains. Only values which do not have any support in a solution space are removed.

Specified by:

consistency in class Constraint

Parameters:

store - constraint store within which the constraint consistency is being checked.

impose

public void impose(Store store)

Description copied from class: Constraint

It imposes the constraint in a given store.

Overrides:

impose in class Constraint

Parameters:

store - the constraint store to which the constraint is imposed to.

getDefaultConsistencyPruningEvent

public int getDefaultConsistencyPruningEvent()

Specified by:

getDefaultConsistencyPruningEvent in class Constraint

toString

public String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Overrides:

toString in class Constraint

imposeDecomposition

public void imposeDecomposition(Store store)

Description copied from class: Constraint

It imposes the decomposition of the given constraint in a given store.

Overrides:

imposeDecomposition in class Constraint

Parameters:

store - the constraint store to which the constraint is imposed to.

decompose

public List<Constraint> decompose(Store store)

Description copied from class: Constraint

It returns an array list of constraint which are used to decompose this constraint. It actually creates a decomposition (possibly also creating variables), but it does not impose the constraint.

Overrides:

decompose in class Constraint

Parameters:

store - the constraint store in which context the decomposition takes place.

Returns:

an array list of constraints used to decompose this constraint.

toLatex

public String toLatex(String addDescription)

It creates a latex description of the constraint state.

Parameters:

addDescription - added description.

Returns:

description of the constraint state.

saveLatexToFile

public void saveLatexToFile(String desc)

It saves the constraint latex description into file.

Parameters:

desc - description of the constraint

setLatexBaseFileName

public void setLatexBaseFileName(String filename)

It sets the filename for the file which is used to save latex descriptions.

Parameters:

filename - the name of the file

uppendToLatexFile

public void uppendToLatexFile(String desc,
                              String fileName)

It appends latex description of the constraint current state to the specified filename.

Parameters:

desc - appended description.

fileName - filename where the description is appended.