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added conversion utility functions for 

FieldMatrix<Fraction> to RealMatrix
  FieldMatrix<BigFraction> to RealMatrix

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@780308 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Luc Maisonobe 2009-05-30 18:36:18 +00:00
parent 525418ab1c
commit aea0ab1242
2 changed files with 115 additions and 0 deletions
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90
src/java/org/apache/commons/math/linear/MatrixUtils.java
View File

@ -24,6 +24,8 @@ import java.util.Arrays;
import org.apache.commons.math.Field;
import org.apache.commons.math.FieldElement;
import org.apache.commons.math.MathRuntimeException;
import org.apache.commons.math.fraction.BigFraction;
import org.apache.commons.math.fraction.Fraction;
/**
* A collection of static methods that operate on or return matrices.
@ -627,4 +629,92 @@ public class MatrixUtils {
}
}
/**
* Convert a {@link FieldMatrix}/{@link Fraction} matrix to a {@link RealMatrix}.
* @param m matrix to convert
* @return converted matrix
*/
public static RealMatrix fractionMatrixToRealMatrix(final FieldMatrix<Fraction> m) {
final FractionMatrixConverter converter = new FractionMatrixConverter();
m.walkInOptimizedOrder(converter);
return converter.getConvertedMatrix();
}
/** Converter for {@link FieldMatrix}/{@link Fraction}. */
private static class FractionMatrixConverter extends DefaultFieldMatrixPreservingVisitor<Fraction> {
/** Converted array. */
private double[][] data;
/** Simple constructor. */
public FractionMatrixConverter() {
super(Fraction.ZERO);
}
/** {@inheritDoc} */
@Override
public void start(int rows, int columns,
int startRow, int endRow, int startColumn, int endColumn) {
data = new double[rows][columns];
}
/** {@inheritDoc} */
@Override
public void visit(int row, int column, Fraction value) {
data[row][column] = value.doubleValue();
}
/** Get the converted matrix.
* @return converted matrix
*/
RealMatrix getConvertedMatrix() {
return new RealMatrixImpl(data, false);
}
}
/**
* Convert a {@link FieldMatrix}/{@link BigFraction} matrix to a {@link RealMatrix}.
* @param m matrix to convert
* @return converted matrix
*/
public static RealMatrix bigFractionMatrixToRealMatrix(final FieldMatrix<BigFraction> m) {
final BigFractionMatrixConverter converter = new BigFractionMatrixConverter();
m.walkInOptimizedOrder(converter);
return converter.getConvertedMatrix();
}
/** Converter for {@link FieldMatrix}/{@link BigFraction}. */
private static class BigFractionMatrixConverter extends DefaultFieldMatrixPreservingVisitor<BigFraction> {
/** Converted array. */
private double[][] data;
/** Simple constructor. */
public BigFractionMatrixConverter() {
super(BigFraction.ZERO);
}
/** {@inheritDoc} */
@Override
public void start(int rows, int columns,
int startRow, int endRow, int startColumn, int endColumn) {
data = new double[rows][columns];
}
/** {@inheritDoc} */
@Override
public void visit(int row, int column, BigFraction value) {
data[row][column] = value.doubleValue();
}
/** Get the converted matrix.
* @return converted matrix
*/
RealMatrix getConvertedMatrix() {
return new RealMatrixImpl(data, false);
}
}
}

25
src/test/org/apache/commons/math/linear/MatrixUtilsTest.java
View File

@ -21,6 +21,7 @@ import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.apache.commons.math.fraction.BigFraction;
import org.apache.commons.math.fraction.Fraction;
import org.apache.commons.math.fraction.FractionConversionException;
import org.apache.commons.math.fraction.FractionField;
@ -322,6 +323,30 @@ public final class MatrixUtilsTest extends TestCase {
}
}
public void testBigFractionConverter() {
BigFraction[][] bfData = {
{ new BigFraction(1), new BigFraction(2), new BigFraction(3) },
{ new BigFraction(2), new BigFraction(5), new BigFraction(3) },
{ new BigFraction(1), new BigFraction(0), new BigFraction(8) }
};
FieldMatrix<BigFraction> m = new FieldMatrixImpl<BigFraction>(bfData, false);
RealMatrix converted = MatrixUtils.bigFractionMatrixToRealMatrix(m);
RealMatrix reference = new RealMatrixImpl(testData, false);
assertEquals(0.0, converted.subtract(reference).getNorm(), 0.0);
}
public void testFractionConverter() {
Fraction[][] fData = {
{ new Fraction(1), new Fraction(2), new Fraction(3) },
{ new Fraction(2), new Fraction(5), new Fraction(3) },
{ new Fraction(1), new Fraction(0), new Fraction(8) }
};
FieldMatrix<Fraction> m = new FieldMatrixImpl<Fraction>(fData, false);
RealMatrix converted = MatrixUtils.fractionMatrixToRealMatrix(m);
RealMatrix reference = new RealMatrixImpl(testData, false);
assertEquals(0.0, converted.subtract(reference).getNorm(), 0.0);
}
public static final Fraction[][] asFraction(double[][] data) {
Fraction d[][] = new Fraction[data.length][];
try {