Module org.maxicp

Package org.maxicp.cp.engine.constraints

Class BinaryKnapsack

java.lang.Object

org.maxicp.cp.engine.core.AbstractCPConstraint

org.maxicp.cp.engine.constraints.BinaryKnapsack

All Implemented Interfaces:

CPConstraint, ConcreteConstraint<ConcreteCPModel>

public class BinaryKnapsack
extends AbstractCPConstraint

A Binary Knapsack constraint ensures that the total load is equal to the sum of the weights of the selected items.

This constraint models

       load = sum_i (b[i] * weights[i])
  

where:

• b[i] is a binary decision variable indicating whether item i is selected (1) or not (0).
• weights[i] represents the weight of item i.
• load is an integer variable representing the total weight of selected items.

Author:

pschaus

Constructor Summary

Constructors

Constructor	Description
BinaryKnapsack(CPBoolVar[] b, int[] weights, int load)	Constraint: load is the sum of the weights of items selected in to the knapsack.
BinaryKnapsack(CPBoolVar[] b, int[] weights, int load, int n)
BinaryKnapsack(CPBoolVar[] b, int[] weights, CPIntVar load)	A Binary Knapsack constraint ensures that the total load is equal to the sum of the weights of the selected items.
BinaryKnapsack(CPBoolVar[] b, int[] weights, CPIntVar load, int n)

Method Summary

Modifier and Type	Method	Description
void	post()	Initializes the constraint when it is posted to the solver.
void	propagate()	Propagates the constraint.

Methods inherited from class org.maxicp.cp.engine.core.AbstractCPConstraint

getSolver, isActive, isScheduled, priority, registerDelta, setActive, setScheduled, updateDeltas

Methods inherited from class java.lang.Object

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

Constructor Details

BinaryKnapsack

public BinaryKnapsack(CPBoolVar[] b,
 int[] weights,
 CPIntVar load,
 int n)

BinaryKnapsack

public BinaryKnapsack(CPBoolVar[] b,
 int[] weights,
 int load,
 int n)

BinaryKnapsack

public BinaryKnapsack(CPBoolVar[] b,
 int[] weights,
 CPIntVar load)

A Binary Knapsack constraint ensures that the total load is equal to the sum of the weights of the selected items.

Parameters:

b - an array of CPBoolVar variables where b[i] is 1 if the item is selected, otherwise 0.

weights - an array of non-negative integers representing the weights of the items. Must have the same length as b.

load - a CPIntVar variable representing the total weight of selected items in the knapsack.

BinaryKnapsack

public BinaryKnapsack(CPBoolVar[] b,
 int[] weights,
 int load)

Constraint: load is the sum of the weights of items selected in to the knapsack.
load = sum_i b[i]*weights[i]
Available propagation strength are Weak and Strong (the default)

Parameters:

b -

weights - a vector of non-negative integers of the same length as b

load -

Method Details

post

public void post()

Description copied from interface: CPConstraint

Initializes the constraint when it is posted to the solver.

Specified by:

post in interface CPConstraint

Overrides:

post in class AbstractCPConstraint

propagate

public void propagate()

Description copied from interface: CPConstraint

Propagates the constraint.

Specified by:

propagate in interface CPConstraint

Overrides:

propagate in class AbstractCPConstraint