Package de.tilman_neumann.jml.factor.base.congruence

Class PartialSolver

java.lang.Object

de.tilman_neumann.jml.factor.base.congruence.PartialSolver

public class PartialSolver
extends Object

A Gaussian solver used to find smooth from partial relations. More specialized algorithms could be used here, but the Gaussian solver works quite fine.

Author:

Tilman Neumann

Constructor Summary

Constructors

Constructor	Description
PartialSolver()

Method Summary

Modifier and Type	Method	Description
void	cleanUp()	Release memory after a factorization.
protected Map<Long,Integer>	createFactor2ColumnIndexMap(Map<Long,ArrayList<Partial>> factors_2_partials)	Create a map from factors appearing with odd exponent to matrix column indices.
String	getName()
protected void	removeSingletons(List<Partial> congruences, Map<Long,ArrayList<Partial>> largeFactors_2_partials)	Remove singletons from congruences.
ArrayList<Smooth>	solve(Collection<? extends Partial> congruences)	Solve a partial congruence equation system.
protected void	solve(List<Partial> congruences, Map<Long,Integer> factors_2_columnIndices)	Create the matrix from the pre-processed congruences and solve it.

Methods inherited from class java.lang.Object

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

Constructor Detail

PartialSolver

public PartialSolver()

Method Detail

getName

public String getName()

solve

public ArrayList<Smooth> solve(Collection<? extends Partial> congruences)

Solve a partial congruence equation system.

Parameters:

congruences - the partial congruence equation system

Returns:

list of smooth congruences found

removeSingletons

protected void removeSingletons(List<Partial> congruences,
                                Map<Long,ArrayList<Partial>> largeFactors_2_partials)

Remove singletons from congruences. This can reduce the size of the equation system; actually it never diminishes the difference (#eqs - #vars). It is very fast, too - like 60ms for a matrix for which solution via Gauss elimination takes 1 minute.

Parameters:

congruences -

largeFactors_2_partials -

createFactor2ColumnIndexMap

protected Map<Long,Integer> createFactor2ColumnIndexMap(Map<Long,ArrayList<Partial>> factors_2_partials)

Create a map from factors appearing with odd exponent to matrix column indices.

Parameters:

factors_2_partials - unsorted map from factors to the congruences in which they appear with odd exponent

Returns:

map from factors to column indices

solve

protected void solve(List<Partial> congruences,
                     Map<Long,Integer> factors_2_columnIndices)

Create the matrix from the pre-processed congruences and solve it.

Parameters:

congruences -

factors_2_columnIndices - map from factors to matrix column indices

cleanUp

public void cleanUp()

Release memory after a factorization.