org.sat4j.minisat.constraints.cnf
Class BinaryClause

java.lang.Object
  extended by org.sat4j.minisat.constraints.cnf.BinaryClause
All Implemented Interfaces:
Serializable, Constr, Propagatable, IConstr
Direct Known Subclasses:
LearntBinaryClause, OriginalBinaryClause

public abstract class BinaryClause
extends Object
implements Constr, Serializable

Data structure for binary clause.

Since:
2.1
Author:
leberre
See Also:
Serialized Form

Field Summary
protected  double activity
           
protected  int head
           
protected  int tail
           
 
Constructor Summary
BinaryClause(IVecInt ps, ILits voc)
          Creates a new basic clause
 
Method Summary
 void assertConstraint(UnitPropagationListener s)
          Method called when the constraint is to be asserted.
 void calcReason(int p, IVecInt outReason)
          Compute the reason for a given assignment.
 boolean canBePropagatedMultipleTimes()
          Partition constraints into the ones that can only be found once on the trail (e.g. clauses) and the ones that can be found several times (e.g.
 boolean equals(Object obj)
           
 int get(int i)
          Retourne le ieme literal de la clause.
 double getActivity()
          To obtain the activity of the constraint.
 int[] getLits()
           
 ILits getVocabulary()
           
 int hashCode()
           
 boolean locked()
          Indicate wether a constraint is responsible from an assignment.
 boolean propagate(UnitPropagationListener s, int p)
          Propagate the truth value of a literal in constraints in which that literal is falsified.
 void register()
          Register the constraint to the solver.
 void remove(UnitPropagationListener upl)
          Remove a constraint from the solver.
 void rescaleBy(double d)
          Rescale the clause activity by a value.
 boolean simplify()
          Simplifies a constraint, by removing top level falsified literals for instance.
 int size()
           
 String toString()
           
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.sat4j.minisat.core.Constr
forwardActivity, incActivity, setLearnt
 
Methods inherited from interface org.sat4j.specs.IConstr
learnt
 

Field Detail

activity

protected double activity

head

protected int head

tail

protected int tail
Constructor Detail

BinaryClause

public BinaryClause(IVecInt ps,
                    ILits voc)
Creates a new basic clause

Parameters:
voc - the vocabulary of the formula
ps - A VecInt that WILL BE EMPTY after calling that method.
Method Detail

calcReason

public void calcReason(int p,
                       IVecInt outReason)
Description copied from interface: Constr
Compute the reason for a given assignment. If the constraint is a clause, it is supposed to be either a unit clause or a falsified one.

Specified by:
calcReason in interface Constr
Parameters:
p - a satisfied literal (or Lit.UNDEFINED)
outReason - the list of falsified literals whose negation is the reason of the assignment of p to true.

remove

public void remove(UnitPropagationListener upl)
Description copied from interface: Constr
Remove a constraint from the solver.

Specified by:
remove in interface Constr

simplify

public boolean simplify()
Description copied from interface: Constr
Simplifies a constraint, by removing top level falsified literals for instance.

Specified by:
simplify in interface Constr
Returns:
true iff the constraint is satisfied and can be removed from the database.

propagate

public boolean propagate(UnitPropagationListener s,
                         int p)
Description copied from interface: Propagatable
Propagate the truth value of a literal in constraints in which that literal is falsified.

Specified by:
propagate in interface Propagatable
Parameters:
s - something able to perform unit propagation
p - the literal being propagated. Its negation must appear in the constraint.
Returns:
false iff an inconsistency (a contradiction) is detected.

locked

public boolean locked()
Description copied from interface: Constr
Indicate wether a constraint is responsible from an assignment.

Specified by:
locked in interface Constr
Returns:
true if a constraint is a "reason" for an assignment.

getActivity

public double getActivity()
Description copied from interface: IConstr
To obtain the activity of the constraint.

Specified by:
getActivity in interface IConstr
Returns:
the activity of the clause

toString

public String toString()
Overrides:
toString in class Object

get

public int get(int i)
Retourne le ieme literal de la clause. Attention, cet ordre change durant la recherche.

Specified by:
get in interface IConstr
Parameters:
i - the index of the literal
Returns:
the literal

rescaleBy

public void rescaleBy(double d)
Description copied from interface: Constr
Rescale the clause activity by a value.

Specified by:
rescaleBy in interface Constr
Parameters:
d -

size

public int size()
Specified by:
size in interface IConstr
Returns:
the number of literals in the constraint.

assertConstraint

public void assertConstraint(UnitPropagationListener s)
Description copied from interface: Constr
Method called when the constraint is to be asserted. It means that the constraint was learnt during the search and it should now propagate some truth values. In the clausal case, only one literal should be propagated. In other cases, it might be different.

Specified by:
assertConstraint in interface Constr
Parameters:
s - a UnitPropagationListener to use for unit propagation.

getVocabulary

public ILits getVocabulary()

getLits

public int[] getLits()

equals

public boolean equals(Object obj)
Overrides:
equals in class Object

hashCode

public int hashCode()
Overrides:
hashCode in class Object

register

public void register()
Description copied from interface: Constr
Register the constraint to the solver.

Specified by:
register in interface Constr

canBePropagatedMultipleTimes

public boolean canBePropagatedMultipleTimes()
Description copied from interface: IConstr
Partition constraints into the ones that can only be found once on the trail (e.g. clauses) and the ones that can be found several times (e.g. cardinality constraints and pseudo-boolean constraints).

Specified by:
canBePropagatedMultipleTimes in interface IConstr
Returns:
true if the constraint can be used several times as a reason to propagate a literal.


Copyright © 2011 Centre de Recherche en Informatique de Lens (CRIL). All Rights Reserved.