Java tutorial
/* * 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.Serializable; import org.apache.commons.math.Field; import org.apache.commons.math.FieldElement; import org.apache.commons.math.MathRuntimeException; import org.apache.commons.math.linear.MatrixVisitorException; import org.apache.commons.math.exception.util.LocalizedFormats; /** * Implementation of FieldMatrix<T> using a {@link FieldElement}[][] array to store entries. * <p> * As specified in the {@link FieldMatrix} interface, matrix element indexing * is 0-based -- e.g., <code>getEntry(0, 0)</code> * returns the element in the first row, first column of the matrix.</li></ul> * </p> * * @param <T> the type of the field elements * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 fvr. 2011) $ */ public class Array2DRowFieldMatrix<T extends FieldElement<T>> extends AbstractFieldMatrix<T> implements Serializable { /** Serializable version identifier */ private static final long serialVersionUID = 7260756672015356458L; /** Entries of the matrix */ protected T[][] data; /** * Creates a matrix with no data * @param field field to which the elements belong */ public Array2DRowFieldMatrix(final Field<T> field) { super(field); } /** * Create a new FieldMatrix<T> with the supplied row and column dimensions. * * @param field field to which the elements belong * @param rowDimension the number of rows in the new matrix * @param columnDimension the number of columns in the new matrix * @throws IllegalArgumentException if row or column dimension is not * positive */ public Array2DRowFieldMatrix(final Field<T> field, final int rowDimension, final int columnDimension) throws IllegalArgumentException { super(field, rowDimension, columnDimension); data = buildArray(field, rowDimension, columnDimension); } /** * Create a new FieldMatrix<T> using the input array as the underlying * data array. * <p>The input array is copied, not referenced. This constructor has * the same effect as calling {@link #Array2DRowFieldMatrix(FieldElement[][], boolean)} * with the second argument set to <code>true</code>.</p> * * @param d data for new matrix * @throws IllegalArgumentException if <code>d</code> is not rectangular * (not all rows have the same length) or empty * @throws NullPointerException if <code>d</code> is null * @see #Array2DRowFieldMatrix(FieldElement[][], boolean) */ public Array2DRowFieldMatrix(final T[][] d) throws IllegalArgumentException, NullPointerException { super(extractField(d)); copyIn(d); } /** * Create a new FieldMatrix<T> using the input array as the underlying * data array. * <p>If an array is built specially in order to be embedded in a * FieldMatrix<T> and not used directly, the <code>copyArray</code> may be * set to <code>false</code. This will prevent the copying and improve * performance as no new array will be built and no data will be copied.</p> * @param d data for new matrix * @param copyArray if true, the input array will be copied, otherwise * it will be referenced * @throws IllegalArgumentException if <code>d</code> is not rectangular * (not all rows have the same length) or empty * @throws NullPointerException if <code>d</code> is null * @see #Array2DRowFieldMatrix(FieldElement[][]) */ public Array2DRowFieldMatrix(final T[][] d, final boolean copyArray) throws IllegalArgumentException, NullPointerException { super(extractField(d)); if (copyArray) { copyIn(d); } else { if (d == null) { throw new NullPointerException(); } final int nRows = d.length; if (nRows == 0) { throw MathRuntimeException.createIllegalArgumentException(LocalizedFormats.AT_LEAST_ONE_ROW); } final int nCols = d[0].length; if (nCols == 0) { throw MathRuntimeException.createIllegalArgumentException(LocalizedFormats.AT_LEAST_ONE_COLUMN); } for (int r = 1; r < nRows; r++) { if (d[r].length != nCols) { throw MathRuntimeException.createIllegalArgumentException( LocalizedFormats.DIFFERENT_ROWS_LENGTHS, nCols, d[r].length); } } data = d; } } /** * Create a new (column) FieldMatrix<T> using <code>v</code> as the * data for the unique column of the <code>v.length x 1</code> matrix * created. * <p>The input array is copied, not referenced.</p> * * @param v column vector holding data for new matrix */ public Array2DRowFieldMatrix(final T[] v) { super(extractField(v)); final int nRows = v.length; data = buildArray(getField(), nRows, 1); for (int row = 0; row < nRows; row++) { data[row][0] = v[row]; } } /** {@inheritDoc} */ @Override public FieldMatrix<T> createMatrix(final int rowDimension, final int columnDimension) throws IllegalArgumentException { return new Array2DRowFieldMatrix<T>(getField(), rowDimension, columnDimension); } /** {@inheritDoc} */ @Override public FieldMatrix<T> copy() { return new Array2DRowFieldMatrix<T>(copyOut(), false); } /** {@inheritDoc} */ @Override public FieldMatrix<T> add(final FieldMatrix<T> m) throws IllegalArgumentException { try { return add((Array2DRowFieldMatrix<T>) m); } catch (ClassCastException cce) { return super.add(m); } } /** * Compute the sum of this and <code>m</code>. * * @param m matrix to be added * @return this + m * @throws IllegalArgumentException if m is not the same size as this */ public Array2DRowFieldMatrix<T> add(final Array2DRowFieldMatrix<T> m) throws IllegalArgumentException { // safety check checkAdditionCompatible(m); final int rowCount = getRowDimension(); final int columnCount = getColumnDimension(); final T[][] outData = buildArray(getField(), rowCount, columnCount); for (int row = 0; row < rowCount; row++) { final T[] dataRow = data[row]; final T[] mRow = m.data[row]; final T[] outDataRow = outData[row]; for (int col = 0; col < columnCount; col++) { outDataRow[col] = dataRow[col].add(mRow[col]); } } return new Array2DRowFieldMatrix<T>(outData, false); } /** {@inheritDoc} */ @Override public FieldMatrix<T> subtract(final FieldMatrix<T> m) throws IllegalArgumentException { try { return subtract((Array2DRowFieldMatrix<T>) m); } catch (ClassCastException cce) { return super.subtract(m); } } /** * Compute this minus <code>m</code>. * * @param m matrix to be subtracted * @return this + m * @throws IllegalArgumentException if m is not the same size as this */ public Array2DRowFieldMatrix<T> subtract(final Array2DRowFieldMatrix<T> m) throws IllegalArgumentException { // safety check checkSubtractionCompatible(m); final int rowCount = getRowDimension(); final int columnCount = getColumnDimension(); final T[][] outData = buildArray(getField(), rowCount, columnCount); for (int row = 0; row < rowCount; row++) { final T[] dataRow = data[row]; final T[] mRow = m.data[row]; final T[] outDataRow = outData[row]; for (int col = 0; col < columnCount; col++) { outDataRow[col] = dataRow[col].subtract(mRow[col]); } } return new Array2DRowFieldMatrix<T>(outData, false); } /** {@inheritDoc} */ @Override public FieldMatrix<T> multiply(final FieldMatrix<T> m) throws IllegalArgumentException { try { return multiply((Array2DRowFieldMatrix<T>) m); } catch (ClassCastException cce) { return super.multiply(m); } } /** * Returns the result of postmultiplying this by <code>m</code>. * @param m matrix to postmultiply by * @return this*m * @throws IllegalArgumentException * if columnDimension(this) != rowDimension(m) */ public Array2DRowFieldMatrix<T> multiply(final Array2DRowFieldMatrix<T> m) throws IllegalArgumentException { // safety check checkMultiplicationCompatible(m); final int nRows = this.getRowDimension(); final int nCols = m.getColumnDimension(); final int nSum = this.getColumnDimension(); final T[][] outData = buildArray(getField(), nRows, nCols); for (int row = 0; row < nRows; row++) { final T[] dataRow = data[row]; final T[] outDataRow = outData[row]; for (int col = 0; col < nCols; col++) { T sum = getField().getZero(); for (int i = 0; i < nSum; i++) { sum = sum.add(dataRow[i].multiply(m.data[i][col])); } outDataRow[col] = sum; } } return new Array2DRowFieldMatrix<T>(outData, false); } /** {@inheritDoc} */ @Override public T[][] getData() { return copyOut(); } /** * Returns a reference to the underlying data array. * <p> * Does <strong>not</strong> make a fresh copy of the underlying data.</p> * * @return 2-dimensional array of entries */ public T[][] getDataRef() { return data; } /** {@inheritDoc} */ @Override public void setSubMatrix(final T[][] subMatrix, final int row, final int column) throws MatrixIndexException { if (data == null) { if (row > 0) { throw MathRuntimeException .createIllegalStateException(LocalizedFormats.FIRST_ROWS_NOT_INITIALIZED_YET, row); } if (column > 0) { throw MathRuntimeException .createIllegalStateException(LocalizedFormats.FIRST_COLUMNS_NOT_INITIALIZED_YET, column); } final int nRows = subMatrix.length; if (nRows == 0) { throw MathRuntimeException.createIllegalArgumentException(LocalizedFormats.AT_LEAST_ONE_ROW); } final int nCols = subMatrix[0].length; if (nCols == 0) { throw MathRuntimeException.createIllegalArgumentException(LocalizedFormats.AT_LEAST_ONE_COLUMN); } data = buildArray(getField(), subMatrix.length, nCols); for (int i = 0; i < data.length; ++i) { if (subMatrix[i].length != nCols) { throw MathRuntimeException.createIllegalArgumentException( LocalizedFormats.DIFFERENT_ROWS_LENGTHS, nCols, subMatrix[i].length); } System.arraycopy(subMatrix[i], 0, data[i + row], column, nCols); } } else { super.setSubMatrix(subMatrix, row, column); } } /** {@inheritDoc} */ @Override public T getEntry(final int row, final int column) throws MatrixIndexException { try { return data[row][column]; } catch (ArrayIndexOutOfBoundsException e) { throw new MatrixIndexException(LocalizedFormats.NO_SUCH_MATRIX_ENTRY, row, column, getRowDimension(), getColumnDimension()); } } /** {@inheritDoc} */ @Override public void setEntry(final int row, final int column, final T value) throws MatrixIndexException { try { data[row][column] = value; } catch (ArrayIndexOutOfBoundsException e) { throw new MatrixIndexException(LocalizedFormats.NO_SUCH_MATRIX_ENTRY, row, column, getRowDimension(), getColumnDimension()); } } /** {@inheritDoc} */ @Override public void addToEntry(final int row, final int column, final T increment) throws MatrixIndexException { try { data[row][column] = data[row][column].add(increment); } catch (ArrayIndexOutOfBoundsException e) { throw new MatrixIndexException(LocalizedFormats.NO_SUCH_MATRIX_ENTRY, row, column, getRowDimension(), getColumnDimension()); } } /** {@inheritDoc} */ @Override public void multiplyEntry(final int row, final int column, final T factor) throws MatrixIndexException { try { data[row][column] = data[row][column].multiply(factor); } catch (ArrayIndexOutOfBoundsException e) { throw new MatrixIndexException(LocalizedFormats.NO_SUCH_MATRIX_ENTRY, row, column, getRowDimension(), getColumnDimension()); } } /** {@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 T[] operate(final T[] v) throws IllegalArgumentException { final int nRows = this.getRowDimension(); final int nCols = this.getColumnDimension(); if (v.length != nCols) { throw MathRuntimeException.createIllegalArgumentException(LocalizedFormats.VECTOR_LENGTH_MISMATCH, v.length, nCols); } final T[] out = buildArray(getField(), nRows); for (int row = 0; row < nRows; row++) { final T[] dataRow = data[row]; T sum = getField().getZero(); for (int i = 0; i < nCols; i++) { sum = sum.add(dataRow[i].multiply(v[i])); } out[row] = sum; } return out; } /** {@inheritDoc} */ @Override public T[] preMultiply(final T[] v) throws IllegalArgumentException { final int nRows = getRowDimension(); final int nCols = getColumnDimension(); if (v.length != nRows) { throw MathRuntimeException.createIllegalArgumentException(LocalizedFormats.VECTOR_LENGTH_MISMATCH, v.length, nRows); } final T[] out = buildArray(getField(), nCols); for (int col = 0; col < nCols; ++col) { T sum = getField().getZero(); for (int i = 0; i < nRows; ++i) { sum = sum.add(data[i][col].multiply(v[i])); } out[col] = sum; } return out; } /** {@inheritDoc} */ @Override public T walkInRowOrder(final FieldMatrixChangingVisitor<T> visitor) throws MatrixVisitorException { 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 T[] rowI = data[i]; for (int j = 0; j < columns; ++j) { rowI[j] = visitor.visit(i, j, rowI[j]); } } return visitor.end(); } /** {@inheritDoc} */ @Override public T walkInRowOrder(final FieldMatrixPreservingVisitor<T> visitor) throws MatrixVisitorException { 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 T[] rowI = data[i]; for (int j = 0; j < columns; ++j) { visitor.visit(i, j, rowI[j]); } } return visitor.end(); } /** {@inheritDoc} */ @Override public T walkInRowOrder(final FieldMatrixChangingVisitor<T> visitor, final int startRow, final int endRow, final int startColumn, final int endColumn) throws MatrixIndexException, MatrixVisitorException { checkSubMatrixIndex(startRow, endRow, startColumn, endColumn); visitor.start(getRowDimension(), getColumnDimension(), startRow, endRow, startColumn, endColumn); for (int i = startRow; i <= endRow; ++i) { final T[] rowI = data[i]; for (int j = startColumn; j <= endColumn; ++j) { rowI[j] = visitor.visit(i, j, rowI[j]); } } return visitor.end(); } /** {@inheritDoc} */ @Override public T walkInRowOrder(final FieldMatrixPreservingVisitor<T> visitor, final int startRow, final int endRow, final int startColumn, final int endColumn) throws MatrixIndexException, MatrixVisitorException { checkSubMatrixIndex(startRow, endRow, startColumn, endColumn); visitor.start(getRowDimension(), getColumnDimension(), startRow, endRow, startColumn, endColumn); for (int i = startRow; i <= endRow; ++i) { final T[] rowI = data[i]; for (int j = startColumn; j <= endColumn; ++j) { visitor.visit(i, j, rowI[j]); } } return visitor.end(); } /** {@inheritDoc} */ @Override public T walkInColumnOrder(final FieldMatrixChangingVisitor<T> visitor) throws MatrixVisitorException { 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 T[] rowI = data[i]; rowI[j] = visitor.visit(i, j, rowI[j]); } } return visitor.end(); } /** {@inheritDoc} */ @Override public T walkInColumnOrder(final FieldMatrixPreservingVisitor<T> visitor) throws MatrixVisitorException { 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 T walkInColumnOrder(final FieldMatrixChangingVisitor<T> visitor, final int startRow, final int endRow, final int startColumn, final int endColumn) throws MatrixIndexException, MatrixVisitorException { checkSubMatrixIndex(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 T[] rowI = data[i]; rowI[j] = visitor.visit(i, j, rowI[j]); } } return visitor.end(); } /** {@inheritDoc} */ @Override public T walkInColumnOrder(final FieldMatrixPreservingVisitor<T> visitor, final int startRow, final int endRow, final int startColumn, final int endColumn) throws MatrixIndexException, MatrixVisitorException { checkSubMatrixIndex(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(); } /** * Returns a fresh copy of the underlying data array. * * @return a copy of the underlying data array. */ private T[][] copyOut() { final int nRows = this.getRowDimension(); final T[][] out = buildArray(getField(), nRows, 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; } /** * Replaces data with a fresh copy of the input array. * <p> * Verifies that the input array is rectangular and non-empty.</p> * * @param in data to copy in * @throws IllegalArgumentException if input array is empty or not * rectangular * @throws NullPointerException if input array is null */ private void copyIn(final T[][] in) { setSubMatrix(in, 0, 0); } }