/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math.linear;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.util.Arrays;
import org.apache.commons.math.Field;
import org.apache.commons.math.FieldElement;
import org.apache.commons.math.exception.OutOfRangeException;
import org.apache.commons.math.exception.NoDataException;
import org.apache.commons.math.exception.NumberIsTooSmallException;
import org.apache.commons.math.exception.NullArgumentException;
import org.apache.commons.math.exception.DimensionMismatchException;
import org.apache.commons.math.exception.ZeroException;
import org.apache.commons.math.exception.util.LocalizedFormats;
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.
*
* @version $Id: MatrixUtils.java 1131229 2011-06-03 20:49:25Z luc $
*/
public class MatrixUtils {
/**
* Private constructor.
*/
private MatrixUtils() {
super();
}
/**
* Returns a {@link RealMatrix} with specified dimensions.
* <p>The type of matrix returned depends on the dimension. Below
* 2<sup>12</sup> elements (i.e. 4096 elements or 64×64 for a
* square matrix) which can be stored in a 32kB array, a {@link
* Array2DRowRealMatrix} instance is built. Above this threshold a {@link
* BlockRealMatrix} instance is built.</p>
* <p>The matrix elements are all set to 0.0.</p>
* @param rows number of rows of the matrix
* @param columns number of columns of the matrix
* @return RealMatrix with specified dimensions
* @see #createRealMatrix(double[][])
*/
public static RealMatrix createRealMatrix(final int rows, final int columns) {
return (rows * columns <= 4096) ?
new Array2DRowRealMatrix(rows, columns) : new BlockRealMatrix(rows, columns);
}
/**
* Returns a {@link FieldMatrix} with specified dimensions.
* <p>The type of matrix returned depends on the dimension. Below
* 2<sup>12</sup> elements (i.e. 4096 elements or 64×64 for a
* square matrix), a {@link FieldMatrix} instance is built. Above
* this threshold a {@link BlockFieldMatrix} instance is built.</p>
* <p>The matrix elements are all set to field.getZero().</p>
* @param <T> the type of the field elements
* @param field field to which the matrix elements belong
* @param rows number of rows of the matrix
* @param columns number of columns of the matrix
* @return FieldMatrix with specified dimensions
* @see #createFieldMatrix(FieldElement[][])
* @since 2.0
*/
public static <T extends FieldElement<T>> FieldMatrix<T> createFieldMatrix(final Field<T> field,
final int rows,
final int columns) {
return (rows * columns <= 4096) ?
new Array2DRowFieldMatrix<T>(field, rows, columns) : new BlockFieldMatrix<T>(field, rows, columns);
}
/**
* Returns a {@link RealMatrix} whose entries are the the values in the
* the input array.
* <p>The type of matrix returned depends on the dimension. Below
* 2<sup>12</sup> elements (i.e. 4096 elements or 64×64 for a
* square matrix) which can be stored in a 32kB array, a {@link
* Array2DRowRealMatrix} instance is built. Above this threshold a {@link
* BlockRealMatrix} instance is built.</p>
* <p>The input array is copied, not referenced.</p>
*
* @param data input array
* @return RealMatrix containing the values of the array
* @throws org.apache.commons.math.exception.DimensionMismatchException
* if {@code data} is not rectangular (not all rows have the same length).
* @throws NoDataException if a row or column is empty.
* @throws NullArgumentException if either {@code data} or {@code data[0]}
* is {@code null}.
* @see #createRealMatrix(int, int)
*/
public static RealMatrix createRealMatrix(double[][] data) {
if (data == null ||
data[0] == null) {
throw new NullArgumentException();
}
return (data.length * data[0].length <= 4096) ?
new Array2DRowRealMatrix(data) : new BlockRealMatrix(data);
}
/**
* Returns a {@link FieldMatrix} whose entries are the the values in the
* the input array.
* <p>The type of matrix returned depends on the dimension. Below
* 2<sup>12</sup> elements (i.e. 4096 elements or 64×64 for a
* square matrix), a {@link FieldMatrix} instance is built. Above
* this threshold a {@link BlockFieldMatrix} instance is built.</p>
* <p>The input array is copied, not referenced.</p>
* @param <T> the type of the field elements
* @param data input array
* @return a matrix containing the values of the array.
* @throws org.apache.commons.math.exception.DimensionMismatchException
* if {@code data} is not rectangular (not all rows have the same length).
* @throws NoDataException if a row or column is empty.
* @throws NullArgumentException if either {@code data} or {@code data[0]}
* is {@code null}.
* @see #createFieldMatrix(Field, int, int)
* @since 2.0
*/
public static <T extends FieldElement<T>> FieldMatrix<T> createFieldMatrix(T[][] data) {
if (data == null ||
data[0] == null) {
throw new NullArgumentException();
}
return (data.length * data[0].length <= 4096) ?
new Array2DRowFieldMatrix<T>(data) : new BlockFieldMatrix<T>(data);
}
/**
* Returns <code>dimension x dimension</code> identity matrix.
*
* @param dimension dimension of identity matrix to generate
* @return identity matrix
* @throws IllegalArgumentException if dimension is not positive
* @since 1.1
*/
public static RealMatrix createRealIdentityMatrix(int dimension) {
final RealMatrix m = createRealMatrix(dimension, dimension);
for (int i = 0; i < dimension; ++i) {
m.setEntry(i, i, 1.0);
}
return m;
}
/**
* Returns <code>dimension x dimension</code> identity matrix.
*
* @param <T> the type of the field elements
* @param field field to which the elements belong
* @param dimension dimension of identity matrix to generate
* @return identity matrix
* @throws IllegalArgumentException if dimension is not positive
* @since 2.0
*/
public static <T extends FieldElement<T>> FieldMatrix<T>
createFieldIdentityMatrix(final Field<T> field, final int dimension) {
final T zero = field.getZero();
final T one = field.getOne();
@SuppressWarnings("unchecked") // zero is type T
final T[][] d = (T[][]) Array.newInstance(zero.getClass(), new int[] { dimension, dimension });
for (int row = 0; row < dimension; row++) {
final T[] dRow = d[row];
Arrays.fill(dRow, zero);
dRow[row] = one;
}
return new Array2DRowFieldMatrix<T>(field, d, false);
}
/**
* Returns a diagonal matrix with specified elements.
*
* @param diagonal diagonal elements of the matrix (the array elements
* will be copied)
* @return diagonal matrix
* @since 2.0
*/
public static RealMatrix createRealDiagonalMatrix(final double[] diagonal) {
final RealMatrix m = createRealMatrix(diagonal.length, diagonal.length);
for (int i = 0; i < diagonal.length; ++i) {
m.setEntry(i, i, diagonal[i]);
}
return m;
}
/**
* Returns a diagonal matrix with specified elements.
*
* @param <T> the type of the field elements
* @param diagonal diagonal elements of the matrix (the array elements
* will be copied)
* @return diagonal matrix
* @since 2.0
*/
public static <T extends FieldElement<T>> FieldMatrix<T>
createFieldDiagonalMatrix(final T[] diagonal) {
final FieldMatrix<T> m =
createFieldMatrix(diagonal[0].getField(), diagonal.length, diagonal.length);
for (int i = 0; i < diagonal.length; ++i) {
m.setEntry(i, i, diagonal[i]);
}
return m;
}
/**
* Creates a {@link RealVector} using the data from the input array.
*
* @param data the input data
* @return a data.length RealVector
* @throws NoDataException if {@code data} is empty.
* @throws NullArgumentException if {@code data} is {@code null}.
*/
public static RealVector createRealVector(double[] data) {
if (data == null) {
throw new NullArgumentException();
}
return new ArrayRealVector(data, true);
}
/**
* Creates a {@link FieldVector} using the data from the input array.
*
* @param <T> the type of the field elements
* @param data the input data
* @return a data.length FieldVector
* @throws NoDataException if {@code data} is empty.
* @throws NullArgumentException if {@code data} is {@code null}.
* @throws ZeroException if {@code data} has 0 elements
*/
public static <T extends FieldElement<T>> FieldVector<T> createFieldVector(final T[] data) {
if (data == null) {
throw new NullArgumentException();
}
if (data.length == 0) {
throw new ZeroException(LocalizedFormats.VECTOR_MUST_HAVE_AT_LEAST_ONE_ELEMENT);
}
return new ArrayFieldVector<T>(data[0].getField(), data, true);
}
/**
* Create a row {@link RealMatrix} using the data from the input
* array.
*
* @param rowData the input row data
* @return a 1 x rowData.length RealMatrix
* @throws NoDataException if {@code rowData} is empty.
* @throws NullArgumentException if {@code rowData} is {@code null}.
*/
public static RealMatrix createRowRealMatrix(double[] rowData) {
if (rowData == null) {
throw new NullArgumentException();
}
final int nCols = rowData.length;
final RealMatrix m = createRealMatrix(1, nCols);
for (int i = 0; i < nCols; ++i) {
m.setEntry(0, i, rowData[i]);
}
return m;
}
/**
* Create a row {@link FieldMatrix} using the data from the input
* array.
*
* @param <T> the type of the field elements
* @param rowData the input row data
* @return a 1 x rowData.length FieldMatrix
* @throws NoDataException if {@code rowData} is empty.
* @throws NullArgumentException if {@code rowData} is {@code null}.
*/
public static <T extends FieldElement<T>> FieldMatrix<T>
createRowFieldMatrix(final T[] rowData) {
if (rowData == null) {
throw new NullArgumentException();
}
final int nCols = rowData.length;
if (nCols == 0) {
throw new NoDataException(LocalizedFormats.AT_LEAST_ONE_COLUMN);
}
final FieldMatrix<T> m = createFieldMatrix(rowData[0].getField(), 1, nCols);
for (int i = 0; i < nCols; ++i) {
m.setEntry(0, i, rowData[i]);
}
return m;
}
/**
* Creates a column {@link RealMatrix} using the data from the input
* array.
*
* @param columnData the input column data
* @return a columnData x 1 RealMatrix
* @throws NoDataException if {@code columnData} is empty.
* @throws NullArgumentException if {@code columnData} is {@code null}.
*/
public static RealMatrix createColumnRealMatrix(double[] columnData) {
if (columnData == null) {
throw new NullArgumentException();
}
final int nRows = columnData.length;
final RealMatrix m = createRealMatrix(nRows, 1);
for (int i = 0; i < nRows; ++i) {
m.setEntry(i, 0, columnData[i]);
}
return m;
}
/**
* Creates a column {@link FieldMatrix} using the data from the input
* array.
*
* @param <T> the type of the field elements
* @param columnData the input column data
* @return a columnData x 1 FieldMatrix
* @throws NoDataException if {@code data} is empty.
* @throws NullArgumentException if {@code columnData} is {@code null}.
*/
public static <T extends FieldElement<T>> FieldMatrix<T>
createColumnFieldMatrix(final T[] columnData) {
if (columnData == null) {
throw new NullArgumentException();
}
final int nRows = columnData.length;
if (nRows == 0) {
throw new NoDataException(LocalizedFormats.AT_LEAST_ONE_ROW);
}
final FieldMatrix<T> m = createFieldMatrix(columnData[0].getField(), nRows, 1);
for (int i = 0; i < nRows; ++i) {
m.setEntry(i, 0, columnData[i]);
}
return m;
}
/**
* Check if matrix indices are valid.
*
* @param m Matrix.
* @param row Row index to check.
* @param column Column index to check.
* @throws OutOfRangeException if {@code row} or {@code column} is not
* a valid index.
*/
public static void checkMatrixIndex(final AnyMatrix m,
final int row, final int column) {
checkRowIndex(m, row);
checkColumnIndex(m, column);
}
/**
* Check if a row index is valid.
*
* @param m Matrix.
* @param row Row index to check.
* @throws OutOfRangeException if {@code row} is not a valid index.
*/
public static void checkRowIndex(final AnyMatrix m, final int row) {
if (row < 0 ||
row >= m.getRowDimension()) {
throw new OutOfRangeException(LocalizedFormats.ROW_INDEX,
row, 0, m.getRowDimension() - 1);
}
}
/**
* Check if a column index is valid.
*
* @param m Matrix.
* @param column Column index to check.
* @throws OutOfRangeException if {@code column} is not a valid index.
*/
public static void checkColumnIndex(final AnyMatrix m, final int column) {
if (column < 0 || column >= m.getColumnDimension()) {
throw new OutOfRangeException(LocalizedFormats.COLUMN_INDEX,
column, 0, m.getColumnDimension() - 1);
}
}
/**
* Check if submatrix ranges indices are valid.
* Rows and columns are indicated counting from 0 to {@code n - 1}.
*
* @param m Matrix.
* @param startRow Initial row index.
* @param endRow Final row index.
* @param startColumn Initial column index.
* @param endColumn Final column index.
* @throws OutOfRangeException if the indices are invalid.
* @throws NumberIsTooSmallException if {@code endRow < startRow} or
* {@code endColumn < startColumn}.
*/
public static void checkSubMatrixIndex(final AnyMatrix m,
final int startRow, final int endRow,
final int startColumn, final int endColumn) {
checkRowIndex(m, startRow);
checkRowIndex(m, endRow);
if (endRow < startRow) {
throw new NumberIsTooSmallException(LocalizedFormats.INITIAL_ROW_AFTER_FINAL_ROW,
endRow, startRow, false);
}
checkColumnIndex(m, startColumn);
checkColumnIndex(m, endColumn);
if (endColumn < startColumn) {
throw new NumberIsTooSmallException(LocalizedFormats.INITIAL_COLUMN_AFTER_FINAL_COLUMN,
endColumn, startColumn, false);
}
}
/**
* Check if submatrix ranges indices are valid.
* Rows and columns are indicated counting from 0 to n-1.
*
* @param m Matrix.
* @param selectedRows Array of row indices.
* @param selectedColumns Array of column indices.
* @throws NullArgumentException if {@code selectedRows} or
* {@code selectedColumns} are {@code null}.
* @throws NoDataException if the row or column selections are empty (zero
* length).
* @throws OutOfRangeException if row or column selections are not valid.
*/
public static void checkSubMatrixIndex(final AnyMatrix m,
final int[] selectedRows,
final int[] selectedColumns) {
if (selectedRows == null) {
throw new NullArgumentException();
}
if (selectedColumns == null) {
throw new NullArgumentException();
}
if (selectedRows.length == 0) {
throw new NoDataException(LocalizedFormats.EMPTY_SELECTED_ROW_INDEX_ARRAY);
}
if (selectedColumns.length == 0) {
throw new NoDataException(LocalizedFormats.EMPTY_SELECTED_COLUMN_INDEX_ARRAY);
}
for (final int row : selectedRows) {
checkRowIndex(m, row);
}
for (final int column : selectedColumns) {
checkColumnIndex(m, column);
}
}
/**
* Check if matrices are addition compatible.
*
* @param left Left hand side matrix.
* @param right Right hand side matrix.
* @throws MatrixDimensionMismatchException if the matrices are not addition compatible.
*/
public static void checkAdditionCompatible(final AnyMatrix left, final AnyMatrix right) {
if ((left.getRowDimension() != right.getRowDimension()) ||
(left.getColumnDimension() != right.getColumnDimension())) {
throw new MatrixDimensionMismatchException(left.getRowDimension(), left.getColumnDimension(),
right.getRowDimension(), right.getColumnDimension());
}
}
/**
* Check if matrices are subtraction compatible
*
* @param left Left hand side matrix.
* @param right Right hand side matrix.
* @throws MatrixDimensionMismatchException if the matrices are not addition compatible.
*/
public static void checkSubtractionCompatible(final AnyMatrix left, final AnyMatrix right) {
if ((left.getRowDimension() != right.getRowDimension()) ||
(left.getColumnDimension() != right.getColumnDimension())) {
throw new MatrixDimensionMismatchException(left.getRowDimension(), left.getColumnDimension(),
right.getRowDimension(), right.getColumnDimension());
}
}
/**
* Check if matrices are multiplication compatible
*
* @param left Left hand side matrix.
* @param right Right hand side matrix.
* @throws DimensionMismatchException if matrices are not multiplication compatible.
*/
public static void checkMultiplicationCompatible(final AnyMatrix left, final AnyMatrix right) {
if (left.getColumnDimension() != right.getRowDimension()) {
throw new DimensionMismatchException(left.getColumnDimension(),
right.getRowDimension());
}
}
/**
* Convert a {@link FieldMatrix}/{@link Fraction} matrix to a {@link RealMatrix}.
* @param m Matrix to convert.
* @return the converted matrix.
*/
public static Array2DRowRealMatrix 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 the converted matrix.
*/
Array2DRowRealMatrix getConvertedMatrix() {
return new Array2DRowRealMatrix(data, false);
}
}
/**
* Convert a {@link FieldMatrix}/{@link BigFraction} matrix to a {@link RealMatrix}.
*
* @param m Matrix to convert.
* @return the converted matrix.
*/
public static Array2DRowRealMatrix 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 the converted matrix.
*/
Array2DRowRealMatrix getConvertedMatrix() {
return new Array2DRowRealMatrix(data, false);
}
}
/** Serialize a {@link RealVector}.
* <p>
* This method is intended to be called from within a private
* <code>writeObject</code> method (after a call to
* <code>oos.defaultWriteObject()</code>) in a class that has a
* {@link RealVector} field, which should be declared <code>transient</code>.
* This way, the default handling does not serialize the vector (the {@link
* RealVector} interface is not serializable by default) but this method does
* serialize it specifically.
* </p>
* <p>
* The following example shows how a simple class with a name and a real vector
* should be written:
* <pre><code>
* public class NamedVector implements Serializable {
*
* private final String name;
* private final transient RealVector coefficients;
*
* // omitted constructors, getters ...
*
* private void writeObject(ObjectOutputStream oos) throws IOException {
* oos.defaultWriteObject(); // takes care of name field
* MatrixUtils.serializeRealVector(coefficients, oos);
* }
*
* private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
* ois.defaultReadObject(); // takes care of name field
* MatrixUtils.deserializeRealVector(this, "coefficients", ois);
* }
*
* }
* </code></pre>
* </p>
*
* @param vector real vector to serialize
* @param oos stream where the real vector should be written
* @exception IOException if object cannot be written to stream
* @see #deserializeRealVector(Object, String, ObjectInputStream)
*/
public static void serializeRealVector(final RealVector vector,
final ObjectOutputStream oos)
throws IOException {
final int n = vector.getDimension();
oos.writeInt(n);
for (int i = 0; i < n; ++i) {
oos.writeDouble(vector.getEntry(i));
}
}
/** Deserialize a {@link RealVector} field in a class.
* <p>
* This method is intended to be called from within a private
* <code>readObject</code> method (after a call to
* <code>ois.defaultReadObject()</code>) in a class that has a
* {@link RealVector} field, which should be declared <code>transient</code>.
* This way, the default handling does not deserialize the vector (the {@link
* RealVector} interface is not serializable by default) but this method does
* deserialize it specifically.
* </p>
* @param instance instance in which the field must be set up
* @param fieldName name of the field within the class (may be private and final)
* @param ois stream from which the real vector should be read
* @exception ClassNotFoundException if a class in the stream cannot be found
* @exception IOException if object cannot be read from the stream
* @see #serializeRealVector(RealVector, ObjectOutputStream)
*/
public static void deserializeRealVector(final Object instance,
final String fieldName,
final ObjectInputStream ois)
throws ClassNotFoundException, IOException {
try {
// read the vector data
final int n = ois.readInt();
final double[] data = new double[n];
for (int i = 0; i < n; ++i) {
data[i] = ois.readDouble();
}
// create the instance
final RealVector vector = new ArrayRealVector(data, false);
// set up the field
final java.lang.reflect.Field f =
instance.getClass().getDeclaredField(fieldName);
f.setAccessible(true);
f.set(instance, vector);
} catch (NoSuchFieldException nsfe) {
IOException ioe = new IOException();
ioe.initCause(nsfe);
throw ioe;
} catch (IllegalAccessException iae) {
IOException ioe = new IOException();
ioe.initCause(iae);
throw ioe;
}
}
/** Serialize a {@link RealMatrix}.
* <p>
* This method is intended to be called from within a private
* <code>writeObject</code> method (after a call to
* <code>oos.defaultWriteObject()</code>) in a class that has a
* {@link RealMatrix} field, which should be declared <code>transient</code>.
* This way, the default handling does not serialize the matrix (the {@link
* RealMatrix} interface is not serializable by default) but this method does
* serialize it specifically.
* </p>
* <p>
* The following example shows how a simple class with a name and a real matrix
* should be written:
* <pre><code>
* public class NamedMatrix implements Serializable {
*
* private final String name;
* private final transient RealMatrix coefficients;
*
* // omitted constructors, getters ...
*
* private void writeObject(ObjectOutputStream oos) throws IOException {
* oos.defaultWriteObject(); // takes care of name field
* MatrixUtils.serializeRealMatrix(coefficients, oos);
* }
*
* private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
* ois.defaultReadObject(); // takes care of name field
* MatrixUtils.deserializeRealMatrix(this, "coefficients", ois);
* }
*
* }
* </code></pre>
* </p>
*
* @param matrix real matrix to serialize
* @param oos stream where the real matrix should be written
* @exception IOException if object cannot be written to stream
* @see #deserializeRealMatrix(Object, String, ObjectInputStream)
*/
public static void serializeRealMatrix(final RealMatrix matrix,
final ObjectOutputStream oos)
throws IOException {
final int n = matrix.getRowDimension();
final int m = matrix.getColumnDimension();
oos.writeInt(n);
oos.writeInt(m);
for (int i = 0; i < n; ++i) {
for (int j = 0; j < m; ++j) {
oos.writeDouble(matrix.getEntry(i, j));
}
}
}
/** Deserialize a {@link RealMatrix} field in a class.
* <p>
* This method is intended to be called from within a private
* <code>readObject</code> method (after a call to
* <code>ois.defaultReadObject()</code>) in a class that has a
* {@link RealMatrix} field, which should be declared <code>transient</code>.
* This way, the default handling does not deserialize the matrix (the {@link
* RealMatrix} interface is not serializable by default) but this method does
* deserialize it specifically.
* </p>
* @param instance instance in which the field must be set up
* @param fieldName name of the field within the class (may be private and final)
* @param ois stream from which the real matrix should be read
* @exception ClassNotFoundException if a class in the stream cannot be found
* @exception IOException if object cannot be read from the stream
* @see #serializeRealMatrix(RealMatrix, ObjectOutputStream)
*/
public static void deserializeRealMatrix(final Object instance,
final String fieldName,
final ObjectInputStream ois)
throws ClassNotFoundException, IOException {
try {
// read the matrix data
final int n = ois.readInt();
final int m = ois.readInt();
final double[][] data = new double[n][m];
for (int i = 0; i < n; ++i) {
final double[] dataI = data[i];
for (int j = 0; j < m; ++j) {
dataI[j] = ois.readDouble();
}
}
// create the instance
final RealMatrix matrix = new Array2DRowRealMatrix(data, false);
// set up the field
final java.lang.reflect.Field f =
instance.getClass().getDeclaredField(fieldName);
f.setAccessible(true);
f.set(instance, matrix);
} catch (NoSuchFieldException nsfe) {
IOException ioe = new IOException();
ioe.initCause(nsfe);
throw ioe;
} catch (IllegalAccessException iae) {
IOException ioe = new IOException();
ioe.initCause(iae);
throw ioe;
}
}
}