Package com.artelys.kalis

Class KSolver

  • public class KSolver
extends java.lang.Object
    KSolver is the main class for solving problems defined in a KProblem instance.

    Once the problem has been fully built, we can begin to look for solutions.
    For this, the main class to be used is KSolver, which allows us to :

    • look for one solution
    • look for all solutions
    • look for another solution when we already know some of them
    • look for the optimal solution according to the problem objective

    A KSolver object must be associated to a specific problem. Here is how we can
    declare and create a KSolver which will be associated to our problem :
    
KSolver mySolver(myProblem);

    When performing its solving functionalities, our object mySolver will store
    all solutions in the myProblem object. Retrieving these solutions and working
    on them is the subject of the next section.

    In order to find only one solution to our problem, we would write:
    
mySolver.solve();

    The solve() method looks for any valid solution and stores it in the
    associated KProblem object.

    In order to fine all solutions to the problem, we would write :
    
mySolver.findAllSolutions();

    The findAllSolutions() method searches for all solutions of the problem and
    stores them in the associated KProblem object.

    When the problem is too large, it can be very time consuming to search for
    all solutions. If one needs to obtain more than one unique solution, then he
    should use the KSolver findNextSolution() method. For example :
    
for (int solutionIndex = 0; solutionIndex < 5; ++solutionIndex)
    mySolver.findNextSolution();
mySolver.endLookingForSolution();

    The findNextSolution() method searches for the next solution and stop in a
    restartable state.
    To go back to the state before search, it is necessary to call the
    endLookingForSolution() method after the successive calls to findNextSolution().

    In order to find the optimal solution to the problem, we would write:
    
mySolver.optimize();

    The optimize() method searches for the optimal solutions according to the
    problem objective and stores it in the associated KProblem object.

    In order to fine tune the search, one may set integer or double control
    parameters using the setIntControl() and setDblControl() methods.

    Statistics on the search can be obtained using the getIntAttrib() and
    getDblAttrib() methods.

    Multi-threaded search is automatically activated provided that the KProblem
    object holds multiple problem instances and that the KSolver::NumberOfThreads
    control parameter is greater than 1.

    See Also:
    KProblem

    • Constructor Detail

      • KSolver

        protected KSolver​(long cPtr,
                  boolean cMemoryOwn)

      • KSolver

        public KSolver()
        Default constructor

      • KSolver

        public KSolver​(KProblem problem)
        Constructor

        Parameters:
        problem - the problem to solve

      • KSolver

        public KSolver​(KProblem problem,
               KBranchingSchemeArray branchingSchemeArray)
        Constructor

        Parameters:
        problem - the problem to solve
        branchingSchemeArray - the resolution strategy used during branch and bound to solve the problem

      • KSolver

        public KSolver​(KSolver toCopy)
        CopyConstructor

    • Method Detail

      • getCPtr

        protected static long getCPtr​(KSolver obj)

      • finalize

        protected void finalize()
        Overrides:
        finalize in class java.lang.Object

      • delete

        public void delete()

      • getProblem

        public KProblem getProblem()
        Get the KProblem instance

      • solve

        public int solve()
        Search for a solution to the problem

        Returns:
        0 if no solution was found, 1 otherwise

        See Also:
        DblControl

      • findAllSolutions

        public int findAllSolutions()
        Search for all solutions to the problem

        Returns:
        number of solutions found

        See Also:
        DblControls

      • findNextSolution

        public int findNextSolution()
        Start looking for a solution to the problem or look for a new one

        Returns:
        0 if no solution was found

        See Also:
        DblControls

      • endLookingForSolution

        public int endLookingForSolution()
        Stop looking for solutions and restore the state before search

      • optimize

        public int optimize​(boolean optimizeWithRestart,
                    boolean dichotomicSearch)
        Search for an optimal solution to the problem.

        Parameters:
        optimizeWithRestart - boolean indicating if the search has to be restarted after finding a solution (@see NumberOfSolutionBetweenRestarts)
        dichotomicSearch - boolean indicating the type of search (linear or dichotomic) to optimize the objective variable (@see OptimizationAlgorithm)
        Returns:
        0 if no solution was found

        See Also:
        DblControls

      • optimize

        public int optimize​(boolean optimizeWithRestart)
        Search for an optimal solution to the problem.

        Parameters:
        optimizeWithRestart - boolean indicating if the search has to be restarted after finding a solution (@see NumberOfSolutionBetweenRestarts)
        Returns:
        0 if no solution was found

        See Also:
        DblControls

      • optimize

        public int optimize()
        Search for an optimal solution to the problem.

        Returns:
        0 if no solution was found

        See Also:
        DblControls

      • getIntAttrib

        public int getIntAttrib​(int attrib)
        Return a integer attribute of the solver.

        Parameters:
        attrib - the integer attribute to retrieve

        See Also:
        KSolver.IntAttrib

      • getDblAttrib

        public double getDblAttrib​(int attrib)
        Return a double attribute of the solver.

        Parameters:
        attrib - the double attribute to retrieve

        See Also:
        KSolver.DblAttrib

      • getIntControl

        public int getIntControl​(int control)
        Return the value of an int control

        Parameters:
        control - integer control to retrieve

        See Also:
        KSolver.IntControl

      • getDblControl

        public double getDblControl​(int control)
        Return the value of a double control

        Parameters:
        control - double control to retrieve

        See Also:
        KSolver.DblControl

      • setIntControl

        public void setIntControl​(int control,
                          int value)
        Set the value of an int control

        Parameters:
        control - the int control to set
        value - the value of the control

        See Also:
        KSolver.IntControl

      • setDblControl

        public void setDblControl​(int control,
                          double value)
        Set the value of a double control

        Parameters:
        control - tjhe double control to set
        value - value of the control

        See Also:
        KSolver.DblControl

      • setNodeFunctionPtr

        public void setNodeFunctionPtr​(com.artelys.kalis.SWIGTYPE_p_f_p_void__int ptr,
                               com.artelys.kalis.SWIGTYPE_p_void param)
        Deprecated.

        Parameters:
        ptr - function pointer
        param - user parameter passed to the function when called
        See Also:
        Set the node explored function ptr

      • setBranchFunctionPtr

        public void setBranchFunctionPtr​(com.artelys.kalis.SWIGTYPE_p_f_p_void__int ptr1,
                                 com.artelys.kalis.SWIGTYPE_p_f_p_void__int ptr2,
                                 com.artelys.kalis.SWIGTYPE_p_void param)
        Deprecated.

        Parameters:
        param - user parameter passed to the function when called
        See Also:
        Set the branch explored function ptr (called each time a branch is explored)

      • setBranchingSchemeFunctionPtr

        public void setBranchingSchemeFunctionPtr​(com.artelys.kalis.SWIGTYPE_p_f_p_void__int ptr1,
                                          com.artelys.kalis.SWIGTYPE_p_void param)
        Deprecated.

        Parameters:
        param - user parameter passed to the function when called
        See Also:
        Set the Branching scheme switch function ptr

      • setAsyncStopFunctionPtr

        public void setAsyncStopFunctionPtr​(com.artelys.kalis.SWIGTYPE_p_f_p_void__int ptr,
                                    com.artelys.kalis.SWIGTYPE_p_void param)

      • setSolutionFunctionPtr

        public void setSolutionFunctionPtr​(com.artelys.kalis.SWIGTYPE_p_f_p_void__int ptr,
                                   com.artelys.kalis.SWIGTYPE_p_void param)
        Deprecated.

        Parameters:
        ptr - function pointer
        param - user parameter passed to the function when called
        See Also:
        Set the solution function ptr (called each time a solution is found)

      • useShaving

        public void useShaving​(boolean use)
        Set shaving activation flag

      • getUseShaving

        public boolean getUseShaving()
        Return the shaving activation flag

      • getCurrentBranchingScheme

        public KBranchingScheme getCurrentBranchingScheme()
        Return the current branching scheme

      • getCurrentVariableSelector

        public KVariableSelector getCurrentVariableSelector()
        Return the current variable selector

      • getCurrentValueSelector

        public KValueSelector getCurrentValueSelector()
        Return the current value selector

      • getCurrentBranchingObject

        public com.artelys.kalis.SWIGTYPE_p_void getCurrentBranchingObject()
        Return a pointer to the current branching object

      • printStats

        public void printStats​(com.artelys.kalis.SWIGTYPE_p_std__ostream fout)
        Pretty printing of resolution statistics

      • printStats

        public void printStats()

      • printStats

        public void printStats​(com.artelys.kalis.SWIGTYPE_p_void ctx,
                       com.artelys.kalis.SWIGTYPE_p_f_p_void_p_q_const__char__int pfp)

      • printStatsFile

        public void printStatsFile​(java.lang.String filename)

      • setBranchingSchemeArray

        public void setBranchingSchemeArray​(KBranchingSchemeArray branchingSchemeArray,
                                    int solverInstance)
        Sets the branching scheme array

      • setBranchingSchemeArray

        public void setBranchingSchemeArray​(KBranchingSchemeArray branchingSchemeArray)
        Sets the branching scheme array

      • getDefaultBranchingSchemeArray

        public KBranchingSchemeArray getDefaultBranchingSchemeArray()
        Return the default branching scheme array

      • addRelaxationSolver

        public void addRelaxationSolver​(KLinearRelaxationSolver solver,
                                boolean initDefaultBranchingScheme)
        Add a relaxation solver

      • addRelaxationSolver

        public void addRelaxationSolver​(KLinearRelaxationSolver solver)
        Add a relaxation solver

      • setUseReducedCostFixing

        public void setUseReducedCostFixing​(boolean flag)
        Use reducing cost fixing

      • localOptimization

        public boolean localOptimization()
        Do a local optimization