org.opt4j.satdecoding
Class Constraint

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractList<E>
          java.util.ArrayList<Term>
              org.opt4j.satdecoding.Constraint

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<Term>, java.util.Collection<Term>, java.util.List<Term>, java.util.RandomAccess

public class Constraint
extends java.util.ArrayList<Term>

A linear pseudo-Boolean Constraint as used in an Integer Linear Program (ILP). A set of Constraints specify a search space.

This Constraint consists of a list of Terms, an Constraint.Operator and a right hand side. E.g., 4a - 3b + not(c) <= 7 is a valid Constraint consisting of three Literals a, b, not(c) with coefficients 4, 3, 1 , the less or equal operator from Constraint.Operator, and the right hand side 7.

This implementation is a plain data structure, i.e., 4a - 3a + c <= 1 is not simplified to a + c <= 1. Moreover, two Constraints are equal if they have an equal Constraint.Operator, right hand side, and equal Terms in the same order.

See Also:

Serialized Form

Nested Class Summary

static class

Constraint.Operator The Constraint.Operators correspond to the Boolean operators <=,=,>=.

Field Summary

protected Constraint.Operator	operator
protected int	rhs

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Constraint()
Constructs a linear Constraint with >=1.

Constraint(Constraint.Operator operator, int rhs)
Constructs a linear Constraint.

Constraint(java.lang.String operator, int rhs)
Constructs a linear Constraint.

Method Summary

void	add(int coeff, Literal lit) Add a Literal with specified coefficient.
void	add(Literal lit) Add a Literal with the coefficient 1.
boolean	contains(Literal literal) Returns true if the Constraint contains the Literal.
Constraint	copy() Copies the Constraint.
boolean	equals(java.lang.Object obj)
java.lang.Iterable<java.lang.Integer>	getCoefficients() Returns an iterable of the coefficients.
java.lang.Iterable<Literal>	getLiterals() Returns an iterable of the Literals.
Constraint.Operator	getOperator() Returns the Constraint.Operator.
int	getRhs() Return the right hand side value.
int	getViolationCount(Model model) Specifies if the Constraint is satisfied for a given Model.
int	hashCode()
boolean	isSatisfied(Model model) Checks, if this constraint is satisfied for a given model.
void	setOperator(Constraint.Operator operator) Sets the Constraint.Operator.
void	setRhs(int rhs) Sets the right hand side value.
java.lang.String	toString()

Methods inherited from class java.util.ArrayList

add, add, addAll, addAll, clear, clone, contains, ensureCapacity, get, indexOf, isEmpty, lastIndexOf, remove, remove, removeRange, set, size, toArray, toArray, trimToSize

Methods inherited from class java.util.AbstractList

iterator, listIterator, listIterator, subList

Methods inherited from class java.util.AbstractCollection

containsAll, removeAll, retainAll

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

containsAll, iterator, listIterator, listIterator, removeAll, retainAll, subList

Field Detail

operator

protected Constraint.Operator operator

rhs

protected int rhs

Constructor Detail

Constraint

public Constraint()

Constructs a linear Constraint with >=1.

Constraint

public Constraint(java.lang.String operator,
                  int rhs)

Constructs a linear Constraint.

Parameters:

operator - the operator (<=,=,>=) as a String

rhs - the right-hand-side value

Constraint

public Constraint(Constraint.Operator operator,
                  int rhs)

Constructs a linear Constraint.

Parameters:

operator - the operator

rhs - the right-hand-side value

Method Detail

getCoefficients

public java.lang.Iterable<java.lang.Integer> getCoefficients()

Returns an iterable of the coefficients.

Returns:

the coefficients

getLiterals

public java.lang.Iterable<Literal> getLiterals()

Returns an iterable of the Literals.

Returns:

the literals.

getOperator

public Constraint.Operator getOperator()

Returns the Constraint.Operator.

Returns:

the operator

See Also:

setOperator(org.opt4j.satdecoding.Constraint.Operator)

setOperator

public void setOperator(Constraint.Operator operator)

Sets the Constraint.Operator.

Parameters:

operator - the operator to be set

See Also:

getOperator()

getRhs

public int getRhs()

Return the right hand side value.

Returns:

the right hand side value

See Also:

setRhs(int)

setRhs

public void setRhs(int rhs)

Sets the right hand side value.

Parameters:

rhs - the right hand side value to set

See Also:

getRhs()

toString

public java.lang.String toString()

Overrides:

toString in class java.util.AbstractCollection<Term>

isSatisfied

public boolean isSatisfied(Model model)

Checks, if this constraint is satisfied for a given model.

Parameters:

model - the model

Returns:

true, iff this constraint is satisfied

getViolationCount

public int getViolationCount(Model model)

Specifies if the Constraint is satisfied for a given Model.

Parameters:

model - the model

Returns:

true if this constraint is satisfied for the model

add

public void add(Literal lit)

Add a Literal with the coefficient 1.

Parameters:

lit - the literal

add

public void add(int coeff,
                Literal lit)

Add a Literal with specified coefficient.

Parameters:

coeff - the coefficient

lit - the literal

copy

public Constraint copy()

Copies the Constraint.

Returns:

a copy of the constraint

contains

public boolean contains(Literal literal)

Returns true if the Constraint contains the Literal.

Parameters:

literal - the literal

Returns:

true if the constrain} contains the literal

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Collection<Term>

Specified by:

hashCode in interface java.util.List<Term>

Overrides:

hashCode in class java.util.AbstractList<Term>

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Collection<Term>

Specified by:

equals in interface java.util.List<Term>

Overrides:

equals in class java.util.AbstractList<Term>