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With inspiration from other libraries
/*
* 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.math3.linear;
import java.io.Serializable;
import org.apache.commons.math3.exception.DimensionMismatchException;
import org.apache.commons.math3.exception.MathIllegalStateException;
import org.apache.commons.math3.exception.NoDataException;
import org.apache.commons.math3.exception.NotStrictlyPositiveException;
import org.apache.commons.math3.exception.NullArgumentException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.exception.OutOfRangeException;
import org.apache.commons.math3.exception.util.LocalizedFormats;
import org.apache.commons.math3.util.MathUtils;
/**
* Implementation of {@link RealMatrix} using a {@code double[][]} array to
* store entries.
*
*/
public class Array2DRowRealMatrix extends AbstractRealMatrix implements Serializable {
/** Serializable version identifier. */
private static final long serialVersionUID = -1067294169172445528L;
/** Entries of the matrix. */
private double data[][];
/**
* Creates a matrix with no data
*/
public Array2DRowRealMatrix() {}
/**
* Create a new RealMatrix with the supplied row and column dimensions.
*
* @param rowDimension Number of rows in the new matrix.
* @param columnDimension Number of columns in the new matrix.
* @throws NotStrictlyPositiveException if the row or column dimension is
* not positive.
*/
public Array2DRowRealMatrix(final int rowDimension,
final int columnDimension)
throws NotStrictlyPositiveException {
super(rowDimension, columnDimension);
data = new double[rowDimension][columnDimension];
}
/**
* Create a new {@code RealMatrix} using the input array as the underlying
* data array.
* The input array is copied, not referenced. This constructor has
* the same effect as calling {@link #Array2DRowRealMatrix(double[][], boolean)}
* with the second argument set to {@code true}.
*
* @param d Data for the new matrix.
* @throws DimensionMismatchException if {@code d} is not rectangular.
* @throws NoDataException if {@code d} row or column dimension is zero.
* @throws NullArgumentException if {@code d} is {@code null}.
* @see #Array2DRowRealMatrix(double[][], boolean)
*/
public Array2DRowRealMatrix(final double[][] d)
throws DimensionMismatchException, NoDataException, NullArgumentException {
copyIn(d);
}
/**
* Create a new RealMatrix using the input array as the underlying
* data array.
* If an array is built specially in order to be embedded in a
* RealMatrix and not used directly, the {@code copyArray} may be
* set to {@code false}. This will prevent the copying and improve
* performance as no new array will be built and no data will be copied.
*
* @param d Data for new matrix.
* @param copyArray if {@code true}, the input array will be copied,
* otherwise it will be referenced.
* @throws DimensionMismatchException if {@code d} is not rectangular.
* @throws NoDataException if {@code d} row or column dimension is zero.
* @throws NullArgumentException if {@code d} is {@code null}.
* @see #Array2DRowRealMatrix(double[][])
*/
public Array2DRowRealMatrix(final double[][] d, final boolean copyArray)
throws DimensionMismatchException, NoDataException,
NullArgumentException {
if (copyArray) {
copyIn(d);
} else {
if (d == null) {
throw new NullArgumentException();
}
final int nRows = d.length;
if (nRows == 0) {
throw new NoDataException(LocalizedFormats.AT_LEAST_ONE_ROW);
}
final int nCols = d[0].length;
if (nCols == 0) {
throw new NoDataException(LocalizedFormats.AT_LEAST_ONE_COLUMN);
}
for (int r = 1; r < nRows; r++) {
if (d[r].length != nCols) {
throw new DimensionMismatchException(d[r].length, nCols);
}
}
data = d;
}
}
/**
* Create a new (column) RealMatrix using {@code v} as the
* data for the unique column of the created matrix.
* The input array is copied.
*
* @param v Column vector holding data for new matrix.
*/
public Array2DRowRealMatrix(final double[] v) {
final int nRows = v.length;
data = new double[nRows][1];
for (int row = 0; row < nRows; row++) {
data[row][0] = v[row];
}
}
/** {@inheritDoc} */
@Override
public RealMatrix createMatrix(final int rowDimension,
final int columnDimension)
throws NotStrictlyPositiveException {
return new Array2DRowRealMatrix(rowDimension, columnDimension);
}
/** {@inheritDoc} */
@Override
public RealMatrix copy() {
return new Array2DRowRealMatrix(copyOut(), false);
}
/**
* Compute the sum of {@code this} and {@code m}.
*
* @param m Matrix to be added.
* @return {@code this + m}.
* @throws MatrixDimensionMismatchException if {@code m} is not the same
* size as {@code this}.
*/
public Array2DRowRealMatrix add(final Array2DRowRealMatrix m)
throws MatrixDimensionMismatchException {
// Safety check.
MatrixUtils.checkAdditionCompatible(this, m);
final int rowCount = getRowDimension();
final int columnCount = getColumnDimension();
final double[][] outData = new double[rowCount][columnCount];
for (int row = 0; row < rowCount; row++) {
final double[] dataRow = data[row];
final double[] mRow = m.data[row];
final double[] outDataRow = outData[row];
for (int col = 0; col < columnCount; col++) {
outDataRow[col] = dataRow[col] + mRow[col];
}
}
return new Array2DRowRealMatrix(outData, false);
}
/**
* Returns {@code this} minus {@code m}.
*
* @param m Matrix to be subtracted.
* @return {@code this - m}
* @throws MatrixDimensionMismatchException if {@code m} is not the same
* size as {@code this}.
*/
public Array2DRowRealMatrix subtract(final Array2DRowRealMatrix m)
throws MatrixDimensionMismatchException {
MatrixUtils.checkSubtractionCompatible(this, m);
final int rowCount = getRowDimension();
final int columnCount = getColumnDimension();
final double[][] outData = new double[rowCount][columnCount];
for (int row = 0; row < rowCount; row++) {
final double[] dataRow = data[row];
final double[] mRow = m.data[row];
final double[] outDataRow = outData[row];
for (int col = 0; col < columnCount; col++) {
outDataRow[col] = dataRow[col] - mRow[col];
}
}
return new Array2DRowRealMatrix(outData, false);
}
/**
* Returns the result of postmultiplying {@code this} by {@code m}.
*
* @param m matrix to postmultiply by
* @return {@code this * m}
* @throws DimensionMismatchException if
* {@code columnDimension(this) != rowDimension(m)}
*/
public Array2DRowRealMatrix multiply(final Array2DRowRealMatrix m)
throws DimensionMismatchException {
MatrixUtils.checkMultiplicationCompatible(this, m);
final int nRows = this.getRowDimension();
final int nCols = m.getColumnDimension();
final int nSum = this.getColumnDimension();
final double[][] outData = new double[nRows][nCols];
// Will hold a column of "m".
final double[] mCol = new double[nSum];
final double[][] mData = m.data;
// Multiply.
for (int col = 0; col < nCols; col++) {
// Copy all elements of column "col" of "m" so that
// will be in contiguous memory.
for (int mRow = 0; mRow < nSum; mRow++) {
mCol[mRow] = mData[mRow][col];
}
for (int row = 0; row < nRows; row++) {
final double[] dataRow = data[row];
double sum = 0;
for (int i = 0; i < nSum; i++) {
sum += dataRow[i] * mCol[i];
}
outData[row][col] = sum;
}
}
return new Array2DRowRealMatrix(outData, false);
}
/** {@inheritDoc} */
@Override
public double[][] getData() {
return copyOut();
}
/**
* Get a reference to the underlying data array.
*
* @return 2-dimensional array of entries.
*/
public double[][] getDataRef() {
return data;
}
/** {@inheritDoc} */
@Override
public void setSubMatrix(final double[][] subMatrix, final int row,
final int column)
throws NoDataException, OutOfRangeException,
DimensionMismatchException, NullArgumentException {
if (data == null) {
if (row > 0) {
throw new MathIllegalStateException(LocalizedFormats.FIRST_ROWS_NOT_INITIALIZED_YET, row);
}
if (column > 0) {
throw new MathIllegalStateException(LocalizedFormats.FIRST_COLUMNS_NOT_INITIALIZED_YET, column);
}
MathUtils.checkNotNull(subMatrix);
final int nRows = subMatrix.length;
if (nRows == 0) {
throw new NoDataException(LocalizedFormats.AT_LEAST_ONE_ROW);
}
final int nCols = subMatrix[0].length;
if (nCols == 0) {
throw new NoDataException(LocalizedFormats.AT_LEAST_ONE_COLUMN);
}
data = new double[subMatrix.length][nCols];
for (int i = 0; i < data.length; ++i) {
if (subMatrix[i].length != nCols) {
throw new DimensionMismatchException(subMatrix[i].length, nCols);
}
System.arraycopy(subMatrix[i], 0, data[i + row], column, nCols);
}
} else {
super.setSubMatrix(subMatrix, row, column);
}
}
/** {@inheritDoc} */
@Override
public double getEntry(final int row, final int column)
throws OutOfRangeException {
MatrixUtils.checkMatrixIndex(this, row, column);
return data[row][column];
}
/** {@inheritDoc} */
@Override
public void setEntry(final int row, final int column, final double value)
throws OutOfRangeException {
MatrixUtils.checkMatrixIndex(this, row, column);
data[row][column] = value;
}
/** {@inheritDoc} */
@Override
public void addToEntry(final int row, final int column,
final double increment)
throws OutOfRangeException {
MatrixUtils.checkMatrixIndex(this, row, column);
data[row][column] += increment;
}
/** {@inheritDoc} */
@Override
public void multiplyEntry(final int row, final int column,
final double factor)
throws OutOfRangeException {
MatrixUtils.checkMatrixIndex(this, row, column);
data[row][column] *= factor;
}
/** {@inheritDoc} */
@Override
public int getRowDimension() {
return (data == null) ? 0 : data.length;
}
/** {@inheritDoc} */
@Override
public int getColumnDimension() {
return ((data == null) || (data[0] == null)) ? 0 : data[0].length;
}
/** {@inheritDoc} */
@Override
public double[] operate(final double[] v)
throws DimensionMismatchException {
final int nRows = this.getRowDimension();
final int nCols = this.getColumnDimension();
if (v.length != nCols) {
throw new DimensionMismatchException(v.length, nCols);
}
final double[] out = new double[nRows];
for (int row = 0; row < nRows; row++) {
final double[] dataRow = data[row];
double sum = 0;
for (int i = 0; i < nCols; i++) {
sum += dataRow[i] * v[i];
}
out[row] = sum;
}
return out;
}
/** {@inheritDoc} */
@Override
public double[] preMultiply(final double[] v)
throws DimensionMismatchException {
final int nRows = getRowDimension();
final int nCols = getColumnDimension();
if (v.length != nRows) {
throw new DimensionMismatchException(v.length, nRows);
}
final double[] out = new double[nCols];
for (int col = 0; col < nCols; ++col) {
double sum = 0;
for (int i = 0; i < nRows; ++i) {
sum += data[i][col] * v[i];
}
out[col] = sum;
}
return out;
}
/** {@inheritDoc} */
@Override
public double walkInRowOrder(final RealMatrixChangingVisitor visitor) {
final int rows = getRowDimension();
final int columns = getColumnDimension();
visitor.start(rows, columns, 0, rows - 1, 0, columns - 1);
for (int i = 0; i < rows; ++i) {
final double[] rowI = data[i];
for (int j = 0; j < columns; ++j) {
rowI[j] = visitor.visit(i, j, rowI[j]);
}
}
return visitor.end();
}
/** {@inheritDoc} */
@Override
public double walkInRowOrder(final RealMatrixPreservingVisitor visitor) {
final int rows = getRowDimension();
final int columns = getColumnDimension();
visitor.start(rows, columns, 0, rows - 1, 0, columns - 1);
for (int i = 0; i < rows; ++i) {
final double[] rowI = data[i];
for (int j = 0; j < columns; ++j) {
visitor.visit(i, j, rowI[j]);
}
}
return visitor.end();
}
/** {@inheritDoc} */
@Override
public double walkInRowOrder(final RealMatrixChangingVisitor visitor,
final int startRow, final int endRow,
final int startColumn, final int endColumn)
throws OutOfRangeException, NumberIsTooSmallException {
MatrixUtils.checkSubMatrixIndex(this, startRow, endRow, startColumn, endColumn);
visitor.start(getRowDimension(), getColumnDimension(),
startRow, endRow, startColumn, endColumn);
for (int i = startRow; i <= endRow; ++i) {
final double[] rowI = data[i];
for (int j = startColumn; j <= endColumn; ++j) {
rowI[j] = visitor.visit(i, j, rowI[j]);
}
}
return visitor.end();
}
/** {@inheritDoc} */
@Override
public double walkInRowOrder(final RealMatrixPreservingVisitor visitor,
final int startRow, final int endRow,
final int startColumn, final int endColumn)
throws OutOfRangeException, NumberIsTooSmallException {
MatrixUtils.checkSubMatrixIndex(this, startRow, endRow, startColumn, endColumn);
visitor.start(getRowDimension(), getColumnDimension(),
startRow, endRow, startColumn, endColumn);
for (int i = startRow; i <= endRow; ++i) {
final double[] rowI = data[i];
for (int j = startColumn; j <= endColumn; ++j) {
visitor.visit(i, j, rowI[j]);
}
}
return visitor.end();
}
/** {@inheritDoc} */
@Override
public double walkInColumnOrder(final RealMatrixChangingVisitor visitor) {
final int rows = getRowDimension();
final int columns = getColumnDimension();
visitor.start(rows, columns, 0, rows - 1, 0, columns - 1);
for (int j = 0; j < columns; ++j) {
for (int i = 0; i < rows; ++i) {
final double[] rowI = data[i];
rowI[j] = visitor.visit(i, j, rowI[j]);
}
}
return visitor.end();
}
/** {@inheritDoc} */
@Override
public double walkInColumnOrder(final RealMatrixPreservingVisitor visitor) {
final int rows = getRowDimension();
final int columns = getColumnDimension();
visitor.start(rows, columns, 0, rows - 1, 0, columns - 1);
for (int j = 0; j < columns; ++j) {
for (int i = 0; i < rows; ++i) {
visitor.visit(i, j, data[i][j]);
}
}
return visitor.end();
}
/** {@inheritDoc} */
@Override
public double walkInColumnOrder(final RealMatrixChangingVisitor visitor,
final int startRow, final int endRow,
final int startColumn, final int endColumn)
throws OutOfRangeException, NumberIsTooSmallException {
MatrixUtils.checkSubMatrixIndex(this, startRow, endRow, startColumn, endColumn);
visitor.start(getRowDimension(), getColumnDimension(),
startRow, endRow, startColumn, endColumn);
for (int j = startColumn; j <= endColumn; ++j) {
for (int i = startRow; i <= endRow; ++i) {
final double[] rowI = data[i];
rowI[j] = visitor.visit(i, j, rowI[j]);
}
}
return visitor.end();
}
/** {@inheritDoc} */
@Override
public double walkInColumnOrder(final RealMatrixPreservingVisitor visitor,
final int startRow, final int endRow,
final int startColumn, final int endColumn)
throws OutOfRangeException, NumberIsTooSmallException {
MatrixUtils.checkSubMatrixIndex(this, startRow, endRow, startColumn, endColumn);
visitor.start(getRowDimension(), getColumnDimension(),
startRow, endRow, startColumn, endColumn);
for (int j = startColumn; j <= endColumn; ++j) {
for (int i = startRow; i <= endRow; ++i) {
visitor.visit(i, j, data[i][j]);
}
}
return visitor.end();
}
/**
* Get a fresh copy of the underlying data array.
*
* @return a copy of the underlying data array.
*/
private double[][] copyOut() {
final int nRows = this.getRowDimension();
final double[][] out = new double[nRows][this.getColumnDimension()];
// can't copy 2-d array in one shot, otherwise get row references
for (int i = 0; i < nRows; i++) {
System.arraycopy(data[i], 0, out[i], 0, data[i].length);
}
return out;
}
/**
* Replace data with a fresh copy of the input array.
*
* @param in Data to copy.
* @throws NoDataException if the input array is empty.
* @throws DimensionMismatchException if the input array is not rectangular.
* @throws NullArgumentException if the input array is {@code null}.
*/
private void copyIn(final double[][] in)
throws DimensionMismatchException, NoDataException, NullArgumentException {
setSubMatrix(in, 0, 0);
}
}