ilog.opl

Class IloCplex.SolveCallback

java.lang.Object

ilog.opl.IloCplex.Callback

ilog.opl.IloCplex.MIPInfoCallback

ilog.opl.IloCplex.MIPCallback

ilog.opl.IloCplex.ControlCallback

ilog.opl.IloCplex.SolveCallback

All Implemented Interfaces:

java.lang.Cloneable

Enclosing class:

IloCplex

public abstract static class IloCplex.SolveCallback
extends IloCplex.ControlCallback

The base class for user-written solve callbacks to control how node relaxations are solved within branch and cut.

An instance of this class can be used to solve nodes during a branch-and-cut search. It allows you to set a starting point when a node is being solved or to select the solution algorithm on a per-node basis.

The constructor and methods of this class are protected to make sure that they are used only to derive a user-written callback class or to implement the main method in it.

See Also:

IloCplex.MIPCallback

Nested Class Summary

Nested classes/interfaces inherited from class ilog.opl.IloCplex.MIPCallback

IloCplex.MIPCallback.NodeData

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	IloCplex.SolveCallback() Constructor for user-written solve callback.

Method Summary

Methods

Modifier and Type	Method and Description
protected IloCplex.CplexStatus	getCplexStatus() Returns the IloCplex.CplexStatus of the last solve call.
protected IloCplex.Status	getStatus() Returns the solution status of the last solve call.
boolean	isDualFeasible() Returns true if a dual feasible solution is available for the current node.
boolean	isPrimalFeasible() Returns true if a primal feasible solution is available for the current node.
protected void	setStart(double[] x, IloNumVar[] var, double[] pi, IloRange[] rng) Specifies a starting point for the next invocation of method solve.
protected void	setStart(double[] x, IloNumVar[] var, int xstart, int xnum, double[] pi, IloRange[] rng, int cstart, int cnum) Specifies a starting point for the next invocation of the method solve.
protected boolean	solve() Solves the current node using the default algorithm (IloCplex.Algorithm.Auto).
protected boolean	solve(int alg) Solves the current node using the algorithm alg.
protected void	useSolution() Instructs IloCplex to use a solution.

Methods inherited from class ilog.opl.IloCplex.ControlCallback

getDownPseudoCost, getFeasibilities, getFeasibilities, getFeasibility, getLB, getLBs, getLBs, getNodeData, getObjValue, getSlack, getSlacks, getSlacks, getSOSFeasibility, getSOSFeasibility, getUB, getUBs, getUBs, getUpPseudoCost, getValue, getValue, getValues, getValues, setNodeData

Methods inherited from class ilog.opl.IloCplex.MIPCallback

getObjCoef, getObjCoefs, getObjCoefs, getUserThreads

Methods inherited from class ilog.opl.IloCplex.MIPInfoCallback

getBestObjValue, getCutoff, getDirection, getIncumbentObjValue, getIncumbentValue, getIncumbentValue, getIncumbentValues, getIncumbentValues, getMIPRelativeGap, getMyThreadNum, getNiterations, getNnodes, getNremainingNodes, getPriority, hasIncumbent

Methods inherited from class ilog.opl.IloCplex.Callback

abort, getCplexTime, getDetTime, getEndDetTime, getEndTime, getEnvImpl, getModel, getNcols, getNQCs, getNrows, getStartDetTime, getStartTime, main

Methods inherited from class java.lang.Object

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

Constructor Detail

IloCplex.SolveCallback

protected IloCplex.SolveCallback()

Constructor for user-written solve callback. This constructor can be called only to construct objects of derived user-written callback classes, but not to construct IloCplex.SolveCallback objects directly.

Method Detail

solve

protected boolean solve(int alg)
                 throws IloException

Solves the current node using the algorithm alg. See IloCplex.Algorithm for a choice of algorithms to use.

Throws:

IloException

Parameters:

alg - The IloCplex.Algorithm to use to solve the current node.

Returns:

A Boolean value indicating whether a feasible solution has been found.

solve

protected boolean solve()
                 throws IloException

Solves the current node using the default algorithm (IloCplex.Algorithm.Auto).

Throws:

IloException

Returns:

A Boolean value indicating whether a feasible solution has been found.

getStatus

protected IloCplex.Status getStatus()
                             throws IloException

Returns the solution status of the last solve call.

Throws:

IloException

Returns:

The solution status of the last solve call.

getCplexStatus

protected IloCplex.CplexStatus getCplexStatus()
                                       throws IloException

Returns the IloCplex.CplexStatus of the last solve call.

Throws:

IloException

Returns:

The IloCplex.CplexStatus of the last solve call.

isDualFeasible

public boolean isDualFeasible()
                       throws IloException

Returns true if a dual feasible solution is available for the current node. If false is returned the solution may still be dual feasible, but the algorithm has not determined the feasibility before it terminated.

Throws:

IloException

isPrimalFeasible

public boolean isPrimalFeasible()
                         throws IloException

Returns true if a primal feasible solution is available for the current node. If false is returned the solution may still be primal feasible, but the algorithm has not determined the feasibility before it terminated.

Throws:

IloException

useSolution

protected void useSolution()

Instructs IloCplex to use a solution.

Instructs IloCplex to use the solution generated with this callback instead of solving the node itself.

If useSolution is not called, IloCplex uses the algorithm selected with parameter IloCplex.IntParam.RootAlg or IloCplex.IntParam.NodeAlg to solve the node.

setStart

protected void setStart(double[] x,
            IloNumVar[] var,
            double[] pi,
            IloRange[] rng)
                 throws IloException

Specifies a starting point for the next invocation of method solve.

Starting point information is exploited at the next call of method solve. In particular, if the node is being solved with the simplex optimizer, the starting point information provided with this method is used to construct a starting basis for the Simplex method.

The starting point information is provided in the parameters of this method. null can be passed for any of the parameters. However, if x is not null, var must not be null. Similarly, if pi is not null, rng must not be null.

For all variables given in var, x[j] specifies the starting primal value for variable var[j]. Similarly, for all constraints specified in rng, pi[i] specifies the starting dual value for rng[i].

Throws:

IloException

Parameters:

x - The array of primal starting values for the variables specified in var.

var - The array of variables for which to specify primal starting values.

pi - The array of dual starting values for the constraints specified in rng.

rng - The array of constraints for which to specify dual starting values.

setStart

protected void setStart(double[] x,
            IloNumVar[] var,
            int xstart,
            int xnum,
            double[] pi,
            IloRange[] rng,
            int cstart,
            int cnum)
                 throws IloException

Specifies a starting point for the next invocation of the method solve.

Starting point information is exploited at the next call of solve. In particular, if the node is being solved with the Simplex optimizer, the starting point information provided with this method is used to construct a starting basis for the Simplex method.

The starting point information is provided in the parameters of this method. null can be passed for any of the parameters. However, if x is not null, var must not be null. Similarly, if pi is not null, rng must not be null.

x[j] specifies the starting primal value for variable var[j]. Similarly, pi[i] specifies the starting dual value for rng[i].

Throws:

IloException

Parameters:

x - An array containing the primal starting values for the variables specified in var.

var - An array containing the variables for which to specify primal starting values.

xstart - The first element in x and var to be used.

xnum - The number of elements in x and var to be used.

pi - An array containing the dual starting values for the constraints specified in rng.

rng - An array containing the constraints for which to specify dual starting values.

cstart - The first element in pi and rng to be used.

cnum - The number of elements in pi and rng to be used.