Class DepthFirstSearch<T extends Var>

  • Type Parameters:
    T - type of variables used in this search.
    All Implemented Interfaces:
    Search<T>
    Direct Known Subclasses:
    PrioritySearch, PrioritySearch.LinkingSearch

    public class DepthFirstSearch<T extends Var>
    extends java.lang.Object
    implements Search<T>
    Implements Depth First Search with number of possible plugins (listeners) to be attached to modify the search.
    Version:
    4.7
    • Field Detail

      • respectSolutionListenerAdvice

        public boolean respectSolutionListenerAdvice
        If it is set to true then the optimizing search will quit the search if this action is indicated by the solution listener.
      • assignSolution

        boolean assignSolution
        It decides if the found solution is immediately assigned to the store.* If the solution is not assigned immediately after the search is concluded but later then special care may be required. As soon as search exits all propagations (including the first time consistency execution of the constraints) may be forgotten. Even worse some values of the variables for which the constraint was never aware of (not even at impose time) may appear back in the domain. The best remedy for this problem is to call store.consistency() method once and only once after the model is imposed and before the search is executed and never remove the level at which the store resides after store.consistency() method is executed.
      • backtracksOut

        long backtracksOut
        It specifies after how many backtracks the search exits.
      • backtracksOutCheck

        boolean backtracksOutCheck
        It specifies if the backtrack out is on.
      • check

        boolean check
        It specifies if search can exit before the search has finished.
      • cost

        Constraint cost
        It represents the constraint which enforces that next solution is better than currently best solution.
      • costValue

        public int costValue
        It represents the cost value of currently best solution for IntVar cost.
      • costValueFloat

        public double costValueFloat
        It represents the cost value of currently best solution for FloatVar cost.
      • costVariable

        public Var costVariable
        It represents the cost variable.
      • optimize

        boolean optimize
      • decisions

        int decisions
        It stores number of nodes with decisions during search.
      • decisionsOut

        long decisionsOut
        It specifies after how many decisions the search exits.
      • decisionsOutCheck

        boolean decisionsOutCheck
        It specifies if the decisions out is on.
      • depth

        int depth
        It represents current depth of store used in search.
      • depthExcludePaths

        int depthExcludePaths
        It stores current depth of the search excluding paths in a search tree.
      • heuristic

        SelectChoicePoint<T extends Var> heuristic
        It represents the choice point selection heuristic.
      • exitChildListener

        public ExitChildListener<T extends Var> exitChildListener
        It is invoked when returning from left or right child.
      • consistencyListener

        public ConsistencyListener consistencyListener
        It is invoked when consistency function has been executed.
      • solutionListener

        public SolutionListener<T extends Var> solutionListener
        It is executed when a solution is found.
      • initializeListener

        public InitializeListener initializeListener
        It is executed when search is started, before entering the search.
      • maxDepth

        int maxDepth
        It stores the maximum depth reached during search.
      • maxDepthExcludePaths

        int maxDepthExcludePaths
        It stores the maximum depth of the search excluding paths.
      • nodes

        int nodes
        It stores number of nodes visited during search.
      • nodesOut

        long nodesOut
        It specifies after how many nodes the search exits.
      • nodesOutCheck

        boolean nodesOutCheck
        It specifies if the nodes out is on.
      • numberBacktracks

        int numberBacktracks
        It stores number of backtracks during search. A backtrack is a search node for which all children has failed.
      • printInfo

        boolean printInfo
        It decides if information about search is printed.
      • childSearches

        public Search<? extends Var>[] childSearches
        It stores searches which will be executed when this one has assign all its variables.
      • masterSearch

        public Search<? extends Var> masterSearch
        If this search is a sub-search then this pointer will point out to the master search (i.e. the search which have invoked this search).
      • store

        public Store store
        It represents store within which a search is performed.
      • timeOutListener

        TimeOutListener timeOutListener
        The object informed about the determination of the timeout.
      • exitListener

        ExitListener exitListener
        It is executed upon search exit. It allows to add learnt constraints.
      • timeOut

        long timeOut
        It specifies the exact time point after which the timeout will occur (in miliseconds).
      • timeOutCheck

        boolean timeOutCheck
        It specifies if the timeout is on.
      • timeOutOccured

        public boolean timeOutOccured
        It specifies that the time-out has occured
      • tOut

        long tOut
        It specifies the number of seconds after which the search will timeout.
      • wrongDecisions

        int wrongDecisions
        It stores number of wrong decisions during search. A wrong decision is a leaf of a search which has failed.
      • wrongDecisionsOut

        long wrongDecisionsOut
        It specifies after how many wrong decisions the search exits.
      • wrongDecisionsOutCheck

        boolean wrongDecisionsOutCheck
        It specifies if the wrong decisions out is on.
      • no

        static java.util.concurrent.atomic.AtomicInteger no
      • id

        public java.lang.String id
        It specifies the id of the search.
      • einAinleftTree

        public boolean einAinleftTree
        It specifies if for setVar based search the left branch should impose EinA constraint.
      • currentChildSearch

        public int currentChildSearch
        It remembers what child search has been already examined.
    • Constructor Detail

      • DepthFirstSearch

        public DepthFirstSearch()
        It specifies current child search.
    • Method Detail

      • setID

        public void setID​(java.lang.String name)
        It sets the id of the store.
        Parameters:
        name - the id of the store object.
      • id

        public java.lang.String id()
        Description copied from interface: Search
        It returns the string id of the search.
        Specified by:
        id in interface Search<T extends Var>
        Returns:
        the string id of the search.
      • setChildSearch

        public void setChildSearch​(Search<? extends Var>[] child)
        Description copied from interface: Search
        It specifies the sub-searches for the current search. In order for the current search to succeed at least one of those must succeed. If there are no sub-searches then the current search succeeds if all variables within select choice point object are assigned and all constraints attached to those variables are satisfied.
        Specified by:
        setChildSearch in interface Search<T extends Var>
        Parameters:
        child - the array containing all children searches.
      • addChildSearch

        public void addChildSearch​(Search<? extends Var> child)
        Description copied from interface: Search
        It adds another child search to this one.
        Specified by:
        addChildSearch in interface Search<T extends Var>
        Parameters:
        child - the search which is being added as child search.
      • setSelectChoicePoint

        public void setSelectChoicePoint​(SelectChoicePoint<T> select)
        Description copied from interface: Search
        It sets the select choice point object.
        Specified by:
        setSelectChoicePoint in interface Search<T extends Var>
        Parameters:
        select - the choice point heuristic used by search.
      • getBacktracks

        public int getBacktracks()
        It returns number of backtracks performed by the search.
        Specified by:
        getBacktracks in interface Search<T extends Var>
        Returns:
        the number of backtracks.
      • getDecisions

        public int getDecisions()
        It returns number of decisions performed by the search.
        Specified by:
        getDecisions in interface Search<T extends Var>
        Returns:
        the number of decisions.
      • getMaximumDepth

        public int getMaximumDepth()
        It returns the maximum depth reached by a search.
        Specified by:
        getMaximumDepth in interface Search<T extends Var>
        Returns:
        the maximum depth.
      • getNodes

        public int getNodes()
        It returns number of search nodes explored by the search.
        Specified by:
        getNodes in interface Search<T extends Var>
        Returns:
        number of search nodes.
      • getWrongDecisions

        public int getWrongDecisions()
        It returns number of wrong decisions performed by the search.
        Specified by:
        getWrongDecisions in interface Search<T extends Var>
        Returns:
        number of wrong decisions.
      • getSolution

        public Domain[] getSolution()
        Description copied from interface: Search
        It returns the solution (an assignment of values to variables).
        Specified by:
        getSolution in interface Search<T extends Var>
        Returns:
        an array constituting the assignments.
      • getSolution

        public Domain[] getSolution​(int no)
        Description copied from interface: Search
        It returns the solution specified by the search. The first solution has an index 1.
        Specified by:
        getSolution in interface Search<T extends Var>
        Parameters:
        no - the solution we are interested in.
        Returns:
        an array constituting the assignments.
      • getVariables

        public T[] getVariables()
        Description copied from interface: Search
        It returns the order of variables used by functions returning a solution in terms of the values.
        Specified by:
        getVariables in interface Search<T extends Var>
        Returns:
        an array of variables as used by functions getSolution.
      • getSolutionListener

        public SolutionListener<T> getSolutionListener()
        Description copied from interface: Search
        It returns the root Solution Listener.
        Specified by:
        getSolutionListener in interface Search<T extends Var>
        Returns:
        the root Solution Listener.
      • label

        public boolean label​(int firstVariable)
        This function is called recursively to assign variables one by one.
        Specified by:
        label in interface Search<T extends Var>
        Parameters:
        firstVariable - the index to the first variable which has not been grounded yet.
        Returns:
        true if the solution was found.
      • setStore

        public void setStore​(Store store)
        Description copied from interface: Search
        It sets the reference to the store in the context of which the search operates.
        Specified by:
        setStore in interface Search<T extends Var>
        Parameters:
        store - the store in which context the search operates.
      • setCostVar

        public void setCostVar​(Var cost)
        Description copied from interface: Search
        It sets the reference to the cost variable. It does not automatically mean that the search optimizes.
        Specified by:
        setCostVar in interface Search<T extends Var>
        Parameters:
        cost - variable used as a cost metric.
      • labeling

        public boolean labeling()
        It is a labeling function called if the search is a sub-search being called from the parent search. It never assigns a solution as it will be immediately retracted by search calling this one.
        Specified by:
        labeling in interface Search<T extends Var>
        Returns:
        true if the solution was found.
      • labeling

        public boolean labeling​(Store store,
                                SelectChoicePoint<T> select)
        Description copied from interface: Search
        It performs search using supplied choice point selection heuristic.
        Specified by:
        labeling in interface Search<T extends Var>
        Parameters:
        store - the store within which the search is conducted.
        select - the selection choice point heuristic.
        Returns:
        true if the solution was found.
      • setOptimizationForChildSearches

        void setOptimizationForChildSearches​(DepthFirstSearch s,
                                             Var costVar)
      • labeling

        public boolean labeling​(Store store,
                                SelectChoicePoint<T> select,
                                Var costVar)
        Description copied from interface: Search
        It performs search using supplied choice point selection heuristic, as well as costVariable as aim at finding an optimal solution.
        Specified by:
        labeling in interface Search<T extends Var>
        Parameters:
        store - constraint store which will be used by labeling.
        select - the selection choice point heuristic.
        costVar - variable to specify cost.
        Returns:
        true if the solution was found.
      • setAssignSolution

        public void setAssignSolution​(boolean value)
        It decides if a solution is assigned to store after search exits.
        Specified by:
        setAssignSolution in interface Search<T extends Var>
        Parameters:
        value - defines if solution is assigned.
      • setBacktracksOut

        public void setBacktracksOut​(long out)
        It turns on the backtrack out.
        Specified by:
        setBacktracksOut in interface Search<T extends Var>
        Parameters:
        out - defines how many backtracks are performed before the search exits.
      • setDecisionsOut

        public void setDecisionsOut​(long out)
        It turns on the decisions out.
        Specified by:
        setDecisionsOut in interface Search<T extends Var>
        Parameters:
        out - defines how many decisions are made before the search exits.
      • setNodesOut

        public void setNodesOut​(long out)
        It turns on the nodes out.
        Specified by:
        setNodesOut in interface Search<T extends Var>
        Parameters:
        out - defines how many nodes are visited before the search exits.
      • setPrintInfo

        public void setPrintInfo​(boolean value)
        It decides if information about search is printed.
        Specified by:
        setPrintInfo in interface Search<T extends Var>
        Parameters:
        value - defines if info is printed to standard output.
      • setTimeOut

        public void setTimeOut​(long out)
        It turns on the timeout.
        Specified by:
        setTimeOut in interface Search<T extends Var>
        Parameters:
        out - defines how many seconds before the search exits.
      • setTimeOutMilliseconds

        public void setTimeOutMilliseconds​(long out)
        Description copied from interface: Search
        It turns on the timeout.
        Specified by:
        setTimeOutMilliseconds in interface Search<T extends Var>
        Parameters:
        out - defines how many miliseconds before the search exits.
      • setWrongDecisionsOut

        public void setWrongDecisionsOut​(long out)
        It turns on the wrong decisions out.
        Specified by:
        setWrongDecisionsOut in interface Search<T extends Var>
        Parameters:
        out - defines how many wrong decisions are made before the search exits.
      • setMasterSearch

        public void setMasterSearch​(Search<? extends Var> master)
        Description copied from interface: Search
        If the search is called by a master search then the search may need to obtain some information about the master search. For example, the textual description of the solution.
        Specified by:
        setMasterSearch in interface Search<T extends Var>
        Parameters:
        master - master search which will be/is calling that slave search.
      • toString

        public java.lang.String toString()
        Specified by:
        toString in interface Search<T extends Var>
        Overrides:
        toString in class java.lang.Object
      • toStringFull

        public java.lang.String toStringFull()
      • assignSolution

        public boolean assignSolution()
        Description copied from interface: Search
        It assigns the last solution.
        Specified by:
        assignSolution in interface Search<T extends Var>
        Returns:
        true if the store is consistent after imposing the last solution.
      • assignSolution

        public boolean assignSolution​(int no)
        Description copied from interface: Search
        The first solution has index 0.
        Specified by:
        assignSolution in interface Search<T extends Var>
        Parameters:
        no - the solution number which we want to enforce in the store.
        Returns:
        true if the store is consistent after imposing the solution.
      • getExitChildListener

        public ExitChildListener<T> getExitChildListener()
        Description copied from interface: Search
        It returns the root of the ExitChildListener.
        Specified by:
        getExitChildListener in interface Search<T extends Var>
        Returns:
        the root of ExitChildListener.
      • getExitListener

        public ExitListener getExitListener()
        Description copied from interface: Search
        It returns the root of the ExitListener.
        Specified by:
        getExitListener in interface Search<T extends Var>
        Returns:
        the root of ExitListener.
      • getTimeOutListener

        public TimeOutListener getTimeOutListener()
        Description copied from interface: Search
        It returns the root of the TimeOutListener.
        Specified by:
        getTimeOutListener in interface Search<T extends Var>
        Returns:
        the root of the TimeOutListener.
      • setSolutionListener

        public void setSolutionListener​(SolutionListener<T> listener)
        Description copied from interface: Search
        It returns the root of the SolutionListener.
        Specified by:
        setSolutionListener in interface Search<T extends Var>
        Parameters:
        listener - the root of the SolutionListener.
      • setConsistencyListener

        public void setConsistencyListener​(ConsistencyListener listener)
        Description copied from interface: Search
        It sets the root of the Consistency Listener.
        Specified by:
        setConsistencyListener in interface Search<T extends Var>
        Parameters:
        listener - the new root.
      • setExitChildListener

        public void setExitChildListener​(ExitChildListener<T> listener)
        Description copied from interface: Search
        It sets the root of the ExitChild listener.
        Specified by:
        setExitChildListener in interface Search<T extends Var>
        Parameters:
        listener - the new root.
      • setExitListener

        public void setExitListener​(ExitListener listener)
        Description copied from interface: Search
        It sets the root of the Exit Listener.
        Specified by:
        setExitListener in interface Search<T extends Var>
        Parameters:
        listener - the new root.
      • setTimeOutListener

        public void setTimeOutListener​(TimeOutListener listener)
        Description copied from interface: Search
        It sets the root of the TimeOutListener.
        Specified by:
        setTimeOutListener in interface Search<T extends Var>
        Parameters:
        listener - the new root.
      • getInitializeListener

        public InitializeListener getInitializeListener()
        Description copied from interface: Search
        It returns the root of the InitializationListener.
        Specified by:
        getInitializeListener in interface Search<T extends Var>
        Returns:
        the root of the InitializeListener.
      • setInitializeListener

        public void setInitializeListener​(InitializeListener listener)
        Description copied from interface: Search
        It sets the root of the InitializeListener.
        Specified by:
        setInitializeListener in interface Search<T extends Var>
        Parameters:
        listener - the new root.
      • printAllSolutions

        public void printAllSolutions()
        Description copied from interface: Search
        It prints all solutions.
        Specified by:
        printAllSolutions in interface Search<T extends Var>
      • getCostVariable

        public Var getCostVariable()
        Description copied from interface: Search
        It returns the cost variable.
        Specified by:
        getCostVariable in interface Search<T extends Var>
        Returns:
        cost variable.
      • getCostValue

        public int getCostValue()
        Description copied from interface: Search
        It returns the value of the cost int variable for the best solution.
        Specified by:
        getCostValue in interface Search<T extends Var>
        Returns:
        the cost value.
      • getCostValueFloat

        public double getCostValueFloat()
        Description copied from interface: Search
        It returns the value of the cost float variable for the best solution.
        Specified by:
        getCostValueFloat in interface Search<T extends Var>
        Returns:
        the cost value.
      • setOptimize

        public void setOptimize​(boolean value)
        Description copied from interface: Search
        It sets the optimization flag.
        Specified by:
        setOptimize in interface Search<T extends Var>
        Parameters:
        value - true if the search should optimize, false otherwise.