org.sat4j.reader

Class DimacsReader

java.lang.Object

org.sat4j.reader.Reader

org.sat4j.reader.DimacsReader

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

GroupedCNFReader

public class DimacsReader
extends Reader
implements Serializable

Very simple Dimacs file parser. Allow solvers to read the constraints from a Dimacs formatted file. It should be used that way:

 DimacsReader solver = new DimacsReader(SolverFactory.OneSolver());
 solver.readInstance("mybench.cnf");
 if (solver.isSatisfiable()) {
     // SAT case
 } else {
     // UNSAT case
 }
 

That parser is not used for efficiency reasons. It will be updated with Java 1.5 scanner feature.

Version:

1.0

Author:

dlb, or

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected int	expectedNbOfConstr
protected String	formatString
protected IVecInt	literals
protected EfficientScanner	scanner
protected ISolver	solver

Constructor Summary

Constructors

Constructor and Description
DimacsReader(ISolver solver)
DimacsReader(ISolver solver, String format)

Method Summary

Methods

Modifier and Type	Method and Description
String	decode(int[] model) Produce a model using the reader format.
void	decode(int[] model, PrintWriter out) Produce a model using the reader format on a provided printwriter.
void	disableNumberOfConstraintCheck()
protected void	flushConstraint()
protected ISolver	getSolver()
protected boolean	handleLine()
IProblem	parseInstance(InputStream in) Read a file from a stream.
protected void	readConstrs()
protected void	readProblemLine()
protected void	skipComments() Skip comments at the beginning of the input stream.

Methods inherited from class org.sat4j.reader.Reader

isVerbose, parseInstance, parseInstance, setVerbosity

Methods inherited from class java.lang.Object

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

Field Detail

expectedNbOfConstr

protected int expectedNbOfConstr

solver

protected final ISolver solver

formatString

protected final String formatString

scanner

protected EfficientScanner scanner

Since:

2.1

literals

protected IVecInt literals

Since:

2.1

Constructor Detail

DimacsReader

public DimacsReader(ISolver solver)

DimacsReader

public DimacsReader(ISolver solver,
            String format)

Method Detail

disableNumberOfConstraintCheck

public void disableNumberOfConstraintCheck()

skipComments

protected void skipComments()
                     throws IOException

Skip comments at the beginning of the input stream.

Parameters:

in - the input stream

Throws:

IOException - if an IO problem occurs.

Since:

2.1

readProblemLine

protected void readProblemLine()
                        throws IOException,
                               ParseFormatException

Parameters:

in - the input stream

Throws:

IOException - iff an IO occurs

ParseFormatException - if the input stream does not comply with the DIMACS format.

Since:

2.1

readConstrs

protected void readConstrs()
                    throws IOException,
                           ParseFormatException,
                           ContradictionException

Parameters:

in - the input stream

Throws:

IOException - iff an IO problems occurs

ParseFormatException - if the input stream does not comply with the DIMACS format.

ContradictionException - si le probl?me est trivialement inconsistant.

Since:

2.1

flushConstraint

protected void flushConstraint()
                        throws ContradictionException

Throws:

ContradictionException

Since:

2.1

handleLine

protected boolean handleLine()
                      throws ContradictionException,
                             IOException,
                             ParseFormatException

Throws:

ContradictionException

IOException

ParseFormatException

Since:

2.1

parseInstance

public IProblem parseInstance(InputStream in)
                       throws ParseFormatException,
                              ContradictionException,
                              IOException

Description copied from class: Reader

Read a file from a stream. It is important to note that benchmarks are usually encoded in ASCII, not UTF8. As such, the only reasonable way to feed a solver from a stream is to use a stream.

Specified by:

parseInstance in class Reader

Parameters:

in - a stream containing the benchmark.

Returns:

the problem to solve (an ISolver in fact).

Throws:

ParseFormatException - if an error occurs during parsing.

ContradictionException - if the problem is found trivially inconsistent.

IOException - if an I/O error occurs.

decode

public String decode(int[] model)

Description copied from class: Reader

Produce a model using the reader format.

Specified by:

decode in class Reader

Parameters:

model - a model using the Dimacs format.

Returns:

a human readable view of the model.

decode

public void decode(int[] model,
          PrintWriter out)

Description copied from class: Reader

Produce a model using the reader format on a provided printwriter.

Specified by:

decode in class Reader

Parameters:

model - a model using the Dimacs format.

out - the place where to display the model

getSolver

protected ISolver getSolver()