com.numericalmethod.suanshu.optimization.constrained.integer.linear.bb

Class ILPNode

java.lang.Object

com.numericalmethod.suanshu.optimization.constrained.integer.linear.bb.ILPNode

All Implemented Interfaces:

BBNode, ConstrainedOptimProblem, OptimProblem, java.io.Serializable

public class ILPNode
extends java.lang.Object
implements BBNode

This is the branch-and-bound node used in conjunction with ILPBranchAndBound to solve an Integer Linear Programming problem.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ILPNode(ILPProblem problem) Construct a BB node and associate it with an ILP problem.

Method Summary

Modifier and Type	Method and Description
java.util.List<ILPNode>	branching() Get the children of this node by using the branching operation.
int	dimension() Get the number of variables.
RealScalarFunction	f() Get the objective function.
EqualityConstraints	getEqualityConstraints() Get the equality constraints, hi(x) = 0
LessThanConstraints	getLessThanConstraints() Get the less-than-or-equal-to constraints, gi(x) ≤ 0
boolean	isCandidate() Check if this node is a possible solution to the original problem, e.g., not pruned.
ImmutableVector	solution() the solution to the sub-problem associated with this node
java.lang.String	toString()
double	value() the value of this node

Methods inherited from class java.lang.Object

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

Constructor Detail

ILPNode

public ILPNode(ILPProblem problem)

Construct a BB node and associate it with an ILP problem.

Parameters:

problem - an ILP problem

Method Detail

solution

public ImmutableVector solution()

Description copied from interface: BBNode

the solution to the sub-problem associated with this node

Specified by:

solution in interface BBNode

Returns:

the solution to the sub-problem associated with this node

value

public double value()

Description copied from interface: BBNode

the value of this node

Specified by:

value in interface BBNode

Returns:

the value of this node

isCandidate

public boolean isCandidate()

Description copied from interface: BBNode

Check if this node is a possible solution to the original problem, e.g., not pruned.

Specified by:

isCandidate in interface BBNode

Returns:

true if this node is a possible solution to the original problem

branching

public java.util.List<ILPNode> branching()

Get the children of this node by using the branching operation.

This implementation assumes

• the parent node has a solution;
• the parent solution has more than 1 non-satisfying integral variable.

Specified by:

branching in interface BBNode

Returns:

getLessThanConstraints

public LessThanConstraints getLessThanConstraints()

Description copied from interface: ConstrainedOptimProblem

Get the less-than-or-equal-to constraints, g_i(x) ≤ 0

Specified by:

getLessThanConstraints in interface ConstrainedOptimProblem

Returns:

the less-than-or-equal-to constraints

getEqualityConstraints

public EqualityConstraints getEqualityConstraints()

Description copied from interface: ConstrainedOptimProblem

Get the equality constraints, h_i(x) = 0

Specified by:

getEqualityConstraints in interface ConstrainedOptimProblem

Returns:

the equality constraints

dimension

public int dimension()

Description copied from interface: OptimProblem

Get the number of variables.

Specified by:

dimension in interface OptimProblem

Returns:

the number of variables.

f

public RealScalarFunction f()

Description copied from interface: OptimProblem

Get the objective function.

Specified by:

f in interface OptimProblem

Returns:

the objective function

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object