net.sf.oriented.omi

Class FactoryFactory

java.lang.Object

net.sf.oriented.omi.FactoryFactory

public final class FactoryFactory
extends Object

This class generates Factory's and SetFactory's for the interfaces in the API. Depending on the Options passed to the constructor, the String representations used by all the factories generated will vary. It is, in general, not possible to pass a String representation output by one group of factories, arising from a particular FactoryFactory to another group of factories, arising from a different FactoryFactory. It is however possible to pass an item constructed from String's between groups of factories.

Various convenience methods are also provided, for some easy ways to produce an oriented matroid.

Author:

jeremy

Constructor Summary

Constructors

Constructor and Description
FactoryFactory() A new FactoryFactory with default options.
FactoryFactory(Options opt) A new FactoryFactory with given Options.

Method Summary

Methods

Modifier and Type	Method and Description
Factory<MatroidAsSet>	bases() A factory for matroids from bases.
ChirotopeFactory	chirotope() A factory for oriented matroids which uses the chirotope representation.
OMSFactory	circuits() A factory for oriented matroids which uses the circuit representation.
static OM	fromCircuits(String circuits) Given a string representation of a set of circuits create an oriented matroid.
static OM	fromCoLexicographic(int n, int r, String chi) Gives an oriented matroid corresponding to a chirotope in colexicographic form.
static OM	fromCrossings(String... crossings) This method is for turning a pseudoline configuration into an oriented matroid.
static OM	fromEuclideanLines(int[][]... lines) Generate an OM from lines being specified as a pair of points (integer coordinates).
static OM	fromLexicographic(int n, int r, String chi) Gives an oriented matroid corresponding to a chirotope in lexicographic form.
static OM	fromMatrix(double threshold, double[][] matrix) This method is for turning a simple matrix of doubles into an oriented matroid over the columns.
static OM	fromMatrix(int[][] matrix) This method is for turning a simple matrix of integers into an oriented matroid over the columns.
Factory<MatroidAsSet>	independentSets() A factory for matroids from independent sets.
LabelFactory	labels() A factory for labels.
OMSFactory	maxVectors() A factory for oriented matroids which uses the maximum vector (co-tope) representation.
Options	options() The options used by this factory.
RealizedFactory	realized() A factory for oriented matroids which uses a realization of the OM as the representation.
SetFactory<SignedSet,SetOfSignedSet>	setsOfSignedSet() A factory for sets of signed sets.
SetFactory<UnsignedSet,SetOfUnsignedSet>	setsOfUnsignedSet() A factory for sets of unsigned sets.
SignedSetFactory	signedSets() A factory for signed sets.
SetFactory<SignedSet,SetOfSignedSet>	symmetricSetsOfSignedSet() A factory for symmetric sets of signed sets.
Factory<MatroidAsSet>	unsignedCircuits() A factory for matroids from circuits.
SetFactory<Label,UnsignedSet>	unsignedSets() A factory for unsigned sets.
OMSFactory	vectors() A factory for oriented matroids which uses the vector representation.

Methods inherited from class java.lang.Object

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

Constructor Detail

FactoryFactory

public FactoryFactory()

A new FactoryFactory with default options.

FactoryFactory

public FactoryFactory(Options opt)

A new FactoryFactory with given Options. These control the String representations used.

Method Detail

labels

public LabelFactory labels()

A factory for labels.

Returns:

A factory for labels.

bases

public Factory<MatroidAsSet> bases()

A factory for matroids from bases.

Returns:

A factory for matroids.

unsignedCircuits

public Factory<MatroidAsSet> unsignedCircuits()

A factory for matroids from circuits.

Returns:

A factory for matroids.

independentSets

public Factory<MatroidAsSet> independentSets()

A factory for matroids from independent sets.

Returns:

A factory for matroids.

circuits

public OMSFactory circuits()

A factory for oriented matroids which uses the circuit representation.

Returns:

A factory for oriented matroids using circuits.

chirotope

public ChirotopeFactory chirotope()

A factory for oriented matroids which uses the chirotope representation.

Returns:

A factory for oriented matroids using chirotopes.

vectors

public OMSFactory vectors()

A factory for oriented matroids which uses the vector representation.

Returns:

A factory for oriented matroids using vectors.

maxVectors

public OMSFactory maxVectors()

A factory for oriented matroids which uses the maximum vector (co-tope) representation.

Returns:

A factory for oriented matroids using maximum vectors.

realized

public RealizedFactory realized()

A factory for oriented matroids which uses a realization of the OM as the representation.

signedSets

public SignedSetFactory signedSets()

A factory for signed sets.

Returns:

A factory for signed sets.

unsignedSets

public SetFactory<Label,UnsignedSet> unsignedSets()

A factory for unsigned sets.

Returns:

A factory for unsigned sets.

setsOfUnsignedSet

public SetFactory<UnsignedSet,SetOfUnsignedSet> setsOfUnsignedSet()

A factory for sets of unsigned sets.

Returns:

A factory for sets of unsigned sets.

setsOfSignedSet

public SetFactory<SignedSet,SetOfSignedSet> setsOfSignedSet()

A factory for sets of signed sets.

Returns:

A factory for sets of signed sets.

symmetricSetsOfSignedSet

public SetFactory<SignedSet,SetOfSignedSet> symmetricSetsOfSignedSet()

A factory for symmetric sets of signed sets. The String representation may omit opposites.

Returns:

A factory for symmetric sets of signed sets.

options

public Options options()

The options used by this factory.

Returns:

The options used by this factory.

fromCoLexicographic

public static OM fromCoLexicographic(int n,
                     int r,
                     String chi)

Gives an oriented matroid corresponding to a chirotope in colexicographic form.

Parameters:

n - The number of elements on which the oriented matroid is defined.

r - The rank

chi - The colexicographic chirotope

Returns:

An oriented matroid

See Also:

ChirotopeFactory.fromCoLexicographic(int, String)

fromLexicographic

public static OM fromLexicographic(int n,
                   int r,
                   String chi)

Gives an oriented matroid corresponding to a chirotope in lexicographic form.

NB: this library uses colexicographic ordering throughout and lexicographic ordering is only available here, and at the two other listed methods.

Parameters:

n - The number of elements on which the oriented matroid is defined.

r - The rank

chi - The lexicographic chirotope

Returns:

An oriented matroid

See Also:

ChirotopeFactory.fromLexicographic(int, String), fromLexicographic(int, int, String), OMasChirotope.toLexicographicString()

fromCircuits

public static OM fromCircuits(String circuits)

Given a string representation of a set of circuits create an oriented matroid.

Parameters:

circuits - A string representation of a set of circuits

Returns:

A oriented matroid.

fromEuclideanLines

public static OM fromEuclideanLines(int[][]... lines)

Generate an OM from lines being specified as a pair of points (integer coordinates).

This is very easy to do from a reasonably precise accurate sketch, see Examples.circularsaw3() for a documented example.

Parameters:

lines - a list of lines each specified by two points by x, y coordinates.

Returns:

An oriented matroid.

fromCrossings

public static OM fromCrossings(String... crossings)

This method is for turning a pseudoline configuration into an oriented matroid. Draw a pseudo line configuration and add a line at infinity going every intersection (parallel lines cross on the line at infinity). Add an origin in a region next to the line at infinity (but inside it). Call the line at infinity A, and then label the other lines going counter-clockwise: B, C, .... the first argument is this information about the line at infinity and is written "A:BC....N" if two or three of these are parallel and cross at infinity e.g. CDE, enclose them in () e.g. "A:B(CDE)F". Then for each of those lines in turn write the line letter and then the lines that it crosses in order, proceeding counterclockwise from the line at infinity. Again if three or more lines meet at a point uses () to show it.

Parameters:

crossings - Information about the order in which the pseudolines cross each other

Returns:

An oriented matroid

fromMatrix

public static OM fromMatrix(int[][] matrix)

This method is for turning a simple matrix of integers into an oriented matroid over the columns. Each array in the array of arrays is a row. The number of arrays is the rank.

Parameters:

matrix -

Returns:

An oriented matroid

fromMatrix

public static OM fromMatrix(double threshold,
            double[][] matrix)

This method is for turning a simple matrix of doubles into an oriented matroid over the columns. Each array in the array of arrays is a row. The number of arrays is the rank. The threshold parameter is to deal with rounding errors. Any determinant which is close to zero is treated as zero, with the largest close-to-zero determinant being at least a factor of threshold smaller than the smallest non-zero determinant.

Parameters:

matrix -

threshold - Should be 1000 ?

Returns:

An oriented matroid