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.math3.linear; import java.util.ArrayList; import java.util.Locale; import org.apache.commons.math3.exception.NoDataException; import org.apache.commons.math3.exception.NotPositiveException; import org.apache.commons.math3.exception.NotStrictlyPositiveException; import org.apache.commons.math3.exception.DimensionMismatchException; 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; import org.apache.commons.math3.util.FastMath; /** * Basic implementation of RealMatrix methods regardless of the underlying storage. * <p>All the methods implemented here use {@link #getEntry(int, int)} to access * matrix elements. Derived class can provide faster implementations.</p> * * @version $Id: AbstractRealMatrix.java 1416643 2012-12-03 19:37:14Z tn $ * @since 2.0 */ public abstract class AbstractRealMatrix extends RealLinearOperator implements RealMatrix { /** Default format. */ private static final RealMatrixFormat DEFAULT_FORMAT = RealMatrixFormat.getInstance(Locale.US); static { // set the minimum fraction digits to 1 to keep compatibility DEFAULT_FORMAT.getFormat().setMinimumFractionDigits(1); } /** * Creates a matrix with no data */ protected AbstractRealMatrix() { } /** * Create a new RealMatrix with the supplied row and column dimensions. * * @param rowDimension the number of rows in the new matrix * @param columnDimension the number of columns in the new matrix * @throws NotStrictlyPositiveException if row or column dimension is not positive */ protected AbstractRealMatrix(final int rowDimension, final int columnDimension) throws NotStrictlyPositiveException { if (rowDimension < 1) { throw new NotStrictlyPositiveException(rowDimension); } if (columnDimension < 1) { throw new NotStrictlyPositiveException(columnDimension); } } /** {@inheritDoc} */ public RealMatrix add(RealMatrix m) throws MatrixDimensionMismatchException { MatrixUtils.checkAdditionCompatible(this, m); final int rowCount = getRowDimension(); final int columnCount = getColumnDimension(); final RealMatrix out = createMatrix(rowCount, columnCount); for (int row = 0; row < rowCount; ++row) { for (int col = 0; col < columnCount; ++col) { out.setEntry(row, col, getEntry(row, col) + m.getEntry(row, col)); } } return out; } /** {@inheritDoc} */ public RealMatrix subtract(final RealMatrix m) throws MatrixDimensionMismatchException { MatrixUtils.checkSubtractionCompatible(this, m); final int rowCount = getRowDimension(); final int columnCount = getColumnDimension(); final RealMatrix out = createMatrix(rowCount, columnCount); for (int row = 0; row < rowCount; ++row) { for (int col = 0; col < columnCount; ++col) { out.setEntry(row, col, getEntry(row, col) - m.getEntry(row, col)); } } return out; } /** {@inheritDoc} */ public RealMatrix scalarAdd(final double d) { final int rowCount = getRowDimension(); final int columnCount = getColumnDimension(); final RealMatrix out = createMatrix(rowCount, columnCount); for (int row = 0; row < rowCount; ++row) { for (int col = 0; col < columnCount; ++col) { out.setEntry(row, col, getEntry(row, col) + d); } } return out; } /** {@inheritDoc} */ public RealMatrix scalarMultiply(final double d) { final int rowCount = getRowDimension(); final int columnCount = getColumnDimension(); final RealMatrix out = createMatrix(rowCount, columnCount); for (int row = 0; row < rowCount; ++row) { for (int col = 0; col < columnCount; ++col) { out.setEntry(row, col, getEntry(row, col) * d); } } return out; } /** {@inheritDoc} */ public RealMatrix multiply(final RealMatrix m) throws DimensionMismatchException { MatrixUtils.checkMultiplicationCompatible(this, m); final int nRows = getRowDimension(); final int nCols = m.getColumnDimension(); final int nSum = getColumnDimension(); final RealMatrix out = createMatrix(nRows, nCols); for (int row = 0; row < nRows; ++row) { for (int col = 0; col < nCols; ++col) { double sum = 0; for (int i = 0; i < nSum; ++i) { sum += getEntry(row, i) * m.getEntry(i, col); } out.setEntry(row, col, sum); } } return out; } /** {@inheritDoc} */ public RealMatrix preMultiply(final RealMatrix m) throws DimensionMismatchException { return m.multiply(this); } /** {@inheritDoc} */ public RealMatrix power(final int p) throws NotPositiveException, NonSquareMatrixException { if (p < 0) { throw new NotPositiveException(LocalizedFormats.NOT_POSITIVE_EXPONENT, p); } if (!isSquare()) { throw new NonSquareMatrixException(getRowDimension(), getColumnDimension()); } if (p == 0) { return MatrixUtils.createRealIdentityMatrix(this.getRowDimension()); } if (p == 1) { return this.copy(); } final int power = p - 1; /* * Only log_2(p) operations is used by doing as follows: * 5^214 = 5^128 * 5^64 * 5^16 * 5^4 * 5^2 * * In general, the same approach is used for A^p. */ final char[] binaryRepresentation = Integer.toBinaryString(power).toCharArray(); final ArrayList<Integer> nonZeroPositions = new ArrayList<Integer>(); int maxI = -1; for (int i = 0; i < binaryRepresentation.length; ++i) { if (binaryRepresentation[i] == '1') { final int pos = binaryRepresentation.length - i - 1; nonZeroPositions.add(pos); // The positions are taken in turn, so maxI is only changed once if (maxI == -1) { maxI = pos; } } } RealMatrix[] results = new RealMatrix[maxI + 1]; results[0] = this.copy(); for (int i = 1; i <= maxI; ++i) { results[i] = results[i - 1].multiply(results[i - 1]); } RealMatrix result = this.copy(); for (Integer i : nonZeroPositions) { result = result.multiply(results[i]); } return result; } /** {@inheritDoc} */ public double[][] getData() { final double[][] data = new double[getRowDimension()][getColumnDimension()]; for (int i = 0; i < data.length; ++i) { final double[] dataI = data[i]; for (int j = 0; j < dataI.length; ++j) { dataI[j] = getEntry(i, j); } } return data; } /** {@inheritDoc} */ public double getNorm() { return walkInColumnOrder(new RealMatrixPreservingVisitor() { /** Last row index. */ private double endRow; /** Sum of absolute values on one column. */ private double columnSum; /** Maximal sum across all columns. */ private double maxColSum; /** {@inheritDoc} */ public void start(final int rows, final int columns, final int startRow, final int endRow, final int startColumn, final int endColumn) { this.endRow = endRow; columnSum = 0; maxColSum = 0; } /** {@inheritDoc} */ public void visit(final int row, final int column, final double value) { columnSum += FastMath.abs(value); if (row == endRow) { maxColSum = FastMath.max(maxColSum, columnSum); columnSum = 0; } } /** {@inheritDoc} */ public double end() { return maxColSum; } }); } /** {@inheritDoc} */ public double getFrobeniusNorm() { return walkInOptimizedOrder(new RealMatrixPreservingVisitor() { /** Sum of squared entries. */ private double sum; /** {@inheritDoc} */ public void start(final int rows, final int columns, final int startRow, final int endRow, final int startColumn, final int endColumn) { sum = 0; } /** {@inheritDoc} */ public void visit(final int row, final int column, final double value) { sum += value * value; } /** {@inheritDoc} */ public double end() { return FastMath.sqrt(sum); } }); } /** {@inheritDoc} */ public RealMatrix getSubMatrix(final int startRow, final int endRow, final int startColumn, final int endColumn) throws OutOfRangeException, NumberIsTooSmallException { MatrixUtils.checkSubMatrixIndex(this, startRow, endRow, startColumn, endColumn); final RealMatrix subMatrix = createMatrix(endRow - startRow + 1, endColumn - startColumn + 1); for (int i = startRow; i <= endRow; ++i) { for (int j = startColumn; j <= endColumn; ++j) { subMatrix.setEntry(i - startRow, j - startColumn, getEntry(i, j)); } } return subMatrix; } /** {@inheritDoc} */ public RealMatrix getSubMatrix(final int[] selectedRows, final int[] selectedColumns) throws NullArgumentException, NoDataException, OutOfRangeException { MatrixUtils.checkSubMatrixIndex(this, selectedRows, selectedColumns); final RealMatrix subMatrix = createMatrix(selectedRows.length, selectedColumns.length); subMatrix.walkInOptimizedOrder(new DefaultRealMatrixChangingVisitor() { /** {@inheritDoc} */ @Override public double visit(final int row, final int column, final double value) { return getEntry(selectedRows[row], selectedColumns[column]); } }); return subMatrix; } /** {@inheritDoc} */ public void copySubMatrix(final int startRow, final int endRow, final int startColumn, final int endColumn, final double[][] destination) throws OutOfRangeException, NumberIsTooSmallException, MatrixDimensionMismatchException { MatrixUtils.checkSubMatrixIndex(this, startRow, endRow, startColumn, endColumn); final int rowsCount = endRow + 1 - startRow; final int columnsCount = endColumn + 1 - startColumn; if ((destination.length < rowsCount) || (destination[0].length < columnsCount)) { throw new MatrixDimensionMismatchException(destination.length, destination[0].length, rowsCount, columnsCount); } walkInOptimizedOrder(new DefaultRealMatrixPreservingVisitor() { /** Initial row index. */ private int startRow; /** Initial column index. */ private int startColumn; /** {@inheritDoc} */ @Override public void start(final int rows, final int columns, final int startRow, final int endRow, final int startColumn, final int endColumn) { this.startRow = startRow; this.startColumn = startColumn; } /** {@inheritDoc} */ @Override public void visit(final int row, final int column, final double value) { destination[row - startRow][column - startColumn] = value; } }, startRow, endRow, startColumn, endColumn); } /** {@inheritDoc} */ public void copySubMatrix(int[] selectedRows, int[] selectedColumns, double[][] destination) throws OutOfRangeException, NullArgumentException, NoDataException, MatrixDimensionMismatchException { MatrixUtils.checkSubMatrixIndex(this, selectedRows, selectedColumns); if ((destination.length < selectedRows.length) || (destination[0].length < selectedColumns.length)) { throw new MatrixDimensionMismatchException(destination.length, destination[0].length, selectedRows.length, selectedColumns.length); } for (int i = 0; i < selectedRows.length; i++) { final double[] destinationI = destination[i]; for (int j = 0; j < selectedColumns.length; j++) { destinationI[j] = getEntry(selectedRows[i], selectedColumns[j]); } } } /** {@inheritDoc} */ public void setSubMatrix(final double[][] subMatrix, final int row, final int column) throws NoDataException, OutOfRangeException, DimensionMismatchException, NullArgumentException { 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); } for (int r = 1; r < nRows; ++r) { if (subMatrix[r].length != nCols) { throw new DimensionMismatchException(nCols, subMatrix[r].length); } } MatrixUtils.checkRowIndex(this, row); MatrixUtils.checkColumnIndex(this, column); MatrixUtils.checkRowIndex(this, nRows + row - 1); MatrixUtils.checkColumnIndex(this, nCols + column - 1); for (int i = 0; i < nRows; ++i) { for (int j = 0; j < nCols; ++j) { setEntry(row + i, column + j, subMatrix[i][j]); } } } /** {@inheritDoc} */ public RealMatrix getRowMatrix(final int row) throws OutOfRangeException { MatrixUtils.checkRowIndex(this, row); final int nCols = getColumnDimension(); final RealMatrix out = createMatrix(1, nCols); for (int i = 0; i < nCols; ++i) { out.setEntry(0, i, getEntry(row, i)); } return out; } /** {@inheritDoc} */ public void setRowMatrix(final int row, final RealMatrix matrix) throws OutOfRangeException, MatrixDimensionMismatchException { MatrixUtils.checkRowIndex(this, row); final int nCols = getColumnDimension(); if ((matrix.getRowDimension() != 1) || (matrix.getColumnDimension() != nCols)) { throw new MatrixDimensionMismatchException(matrix.getRowDimension(), matrix.getColumnDimension(), 1, nCols); } for (int i = 0; i < nCols; ++i) { setEntry(row, i, matrix.getEntry(0, i)); } } /** {@inheritDoc} */ public RealMatrix getColumnMatrix(final int column) throws OutOfRangeException { MatrixUtils.checkColumnIndex(this, column); final int nRows = getRowDimension(); final RealMatrix out = createMatrix(nRows, 1); for (int i = 0; i < nRows; ++i) { out.setEntry(i, 0, getEntry(i, column)); } return out; } /** {@inheritDoc} */ public void setColumnMatrix(final int column, final RealMatrix matrix) throws OutOfRangeException, MatrixDimensionMismatchException { MatrixUtils.checkColumnIndex(this, column); final int nRows = getRowDimension(); if ((matrix.getRowDimension() != nRows) || (matrix.getColumnDimension() != 1)) { throw new MatrixDimensionMismatchException(matrix.getRowDimension(), matrix.getColumnDimension(), nRows, 1); } for (int i = 0; i < nRows; ++i) { setEntry(i, column, matrix.getEntry(i, 0)); } } /** {@inheritDoc} */ public RealVector getRowVector(final int row) throws OutOfRangeException { return new ArrayRealVector(getRow(row), false); } /** {@inheritDoc} */ public void setRowVector(final int row, final RealVector vector) throws OutOfRangeException, MatrixDimensionMismatchException { MatrixUtils.checkRowIndex(this, row); final int nCols = getColumnDimension(); if (vector.getDimension() != nCols) { throw new MatrixDimensionMismatchException(1, vector.getDimension(), 1, nCols); } for (int i = 0; i < nCols; ++i) { setEntry(row, i, vector.getEntry(i)); } } /** {@inheritDoc} */ public RealVector getColumnVector(final int column) throws OutOfRangeException { return new ArrayRealVector(getColumn(column), false); } /** {@inheritDoc} */ public void setColumnVector(final int column, final RealVector vector) throws OutOfRangeException, MatrixDimensionMismatchException { MatrixUtils.checkColumnIndex(this, column); final int nRows = getRowDimension(); if (vector.getDimension() != nRows) { throw new MatrixDimensionMismatchException(vector.getDimension(), 1, nRows, 1); } for (int i = 0; i < nRows; ++i) { setEntry(i, column, vector.getEntry(i)); } } /** {@inheritDoc} */ public double[] getRow(final int row) throws OutOfRangeException { MatrixUtils.checkRowIndex(this, row); final int nCols = getColumnDimension(); final double[] out = new double[nCols]; for (int i = 0; i < nCols; ++i) { out[i] = getEntry(row, i); } return out; } /** {@inheritDoc} */ public void setRow(final int row, final double[] array) throws OutOfRangeException, MatrixDimensionMismatchException { MatrixUtils.checkRowIndex(this, row); final int nCols = getColumnDimension(); if (array.length != nCols) { throw new MatrixDimensionMismatchException(1, array.length, 1, nCols); } for (int i = 0; i < nCols; ++i) { setEntry(row, i, array[i]); } } /** {@inheritDoc} */ public double[] getColumn(final int column) throws OutOfRangeException { MatrixUtils.checkColumnIndex(this, column); final int nRows = getRowDimension(); final double[] out = new double[nRows]; for (int i = 0; i < nRows; ++i) { out[i] = getEntry(i, column); } return out; } /** {@inheritDoc} */ public void setColumn(final int column, final double[] array) throws OutOfRangeException, MatrixDimensionMismatchException { MatrixUtils.checkColumnIndex(this, column); final int nRows = getRowDimension(); if (array.length != nRows) { throw new MatrixDimensionMismatchException(array.length, 1, nRows, 1); } for (int i = 0; i < nRows; ++i) { setEntry(i, column, array[i]); } } /** {@inheritDoc} */ public void addToEntry(int row, int column, double increment) throws OutOfRangeException { MatrixUtils.checkMatrixIndex(this, row, column); setEntry(row, column, getEntry(row, column) + increment); } /** {@inheritDoc} */ public void multiplyEntry(int row, int column, double factor) throws OutOfRangeException { MatrixUtils.checkMatrixIndex(this, row, column); setEntry(row, column, getEntry(row, column) * factor); } /** {@inheritDoc} */ public RealMatrix transpose() { final int nRows = getRowDimension(); final int nCols = getColumnDimension(); final RealMatrix out = createMatrix(nCols, nRows); walkInOptimizedOrder(new DefaultRealMatrixPreservingVisitor() { /** {@inheritDoc} */ @Override public void visit(final int row, final int column, final double value) { out.setEntry(column, row, value); } }); return out; } /** {@inheritDoc} */ public boolean isSquare() { return getColumnDimension() == getRowDimension(); } /** * Returns the number of rows of this matrix. * * @return the number of rows. */ @Override public abstract int getRowDimension(); /** * Returns the number of columns of this matrix. * * @return the number of columns. */ @Override public abstract int getColumnDimension(); /** {@inheritDoc} */ public double getTrace() throws NonSquareMatrixException { final int nRows = getRowDimension(); final int nCols = getColumnDimension(); if (nRows != nCols) { throw new NonSquareMatrixException(nRows, nCols); } double trace = 0; for (int i = 0; i < nRows; ++i) { trace += getEntry(i, i); } return trace; } /** {@inheritDoc} */ public double[] operate(final double[] v) throws DimensionMismatchException { final int nRows = getRowDimension(); final int nCols = getColumnDimension(); if (v.length != nCols) { throw new DimensionMismatchException(v.length, nCols); } final double[] out = new double[nRows]; for (int row = 0; row < nRows; ++row) { double sum = 0; for (int i = 0; i < nCols; ++i) { sum += getEntry(row, i) * v[i]; } out[row] = sum; } return out; } /** {@inheritDoc} */ @Override public RealVector operate(final RealVector v) throws DimensionMismatchException { try { return new ArrayRealVector(operate(((ArrayRealVector) v).getDataRef()), false); } catch (ClassCastException cce) { final int nRows = getRowDimension(); final int nCols = getColumnDimension(); if (v.getDimension() != nCols) { throw new DimensionMismatchException(v.getDimension(), nCols); } final double[] out = new double[nRows]; for (int row = 0; row < nRows; ++row) { double sum = 0; for (int i = 0; i < nCols; ++i) { sum += getEntry(row, i) * v.getEntry(i); } out[row] = sum; } return new ArrayRealVector(out, false); } } /** {@inheritDoc} */ 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 += getEntry(i, col) * v[i]; } out[col] = sum; } return out; } /** {@inheritDoc} */ public RealVector preMultiply(final RealVector v) throws DimensionMismatchException { try { return new ArrayRealVector(preMultiply(((ArrayRealVector) v).getDataRef()), false); } catch (ClassCastException cce) { final int nRows = getRowDimension(); final int nCols = getColumnDimension(); if (v.getDimension() != nRows) { throw new DimensionMismatchException(v.getDimension(), 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 += getEntry(i, col) * v.getEntry(i); } out[col] = sum; } return new ArrayRealVector(out, false); } } /** {@inheritDoc} */ 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 row = 0; row < rows; ++row) { for (int column = 0; column < columns; ++column) { final double oldValue = getEntry(row, column); final double newValue = visitor.visit(row, column, oldValue); setEntry(row, column, newValue); } } return visitor.end(); } /** {@inheritDoc} */ 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 row = 0; row < rows; ++row) { for (int column = 0; column < columns; ++column) { visitor.visit(row, column, getEntry(row, column)); } } return visitor.end(); } /** {@inheritDoc} */ 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 row = startRow; row <= endRow; ++row) { for (int column = startColumn; column <= endColumn; ++column) { final double oldValue = getEntry(row, column); final double newValue = visitor.visit(row, column, oldValue); setEntry(row, column, newValue); } } return visitor.end(); } /** {@inheritDoc} */ 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 row = startRow; row <= endRow; ++row) { for (int column = startColumn; column <= endColumn; ++column) { visitor.visit(row, column, getEntry(row, column)); } } return visitor.end(); } /** {@inheritDoc} */ 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 column = 0; column < columns; ++column) { for (int row = 0; row < rows; ++row) { final double oldValue = getEntry(row, column); final double newValue = visitor.visit(row, column, oldValue); setEntry(row, column, newValue); } } return visitor.end(); } /** {@inheritDoc} */ 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 column = 0; column < columns; ++column) { for (int row = 0; row < rows; ++row) { visitor.visit(row, column, getEntry(row, column)); } } return visitor.end(); } /** {@inheritDoc} */ 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 column = startColumn; column <= endColumn; ++column) { for (int row = startRow; row <= endRow; ++row) { final double oldValue = getEntry(row, column); final double newValue = visitor.visit(row, column, oldValue); setEntry(row, column, newValue); } } return visitor.end(); } /** {@inheritDoc} */ 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 column = startColumn; column <= endColumn; ++column) { for (int row = startRow; row <= endRow; ++row) { visitor.visit(row, column, getEntry(row, column)); } } return visitor.end(); } /** {@inheritDoc} */ public double walkInOptimizedOrder(final RealMatrixChangingVisitor visitor) { return walkInRowOrder(visitor); } /** {@inheritDoc} */ public double walkInOptimizedOrder(final RealMatrixPreservingVisitor visitor) { return walkInRowOrder(visitor); } /** {@inheritDoc} */ public double walkInOptimizedOrder(final RealMatrixChangingVisitor visitor, final int startRow, final int endRow, final int startColumn, final int endColumn) throws OutOfRangeException, NumberIsTooSmallException { return walkInRowOrder(visitor, startRow, endRow, startColumn, endColumn); } /** {@inheritDoc} */ public double walkInOptimizedOrder(final RealMatrixPreservingVisitor visitor, final int startRow, final int endRow, final int startColumn, final int endColumn) throws OutOfRangeException, NumberIsTooSmallException { return walkInRowOrder(visitor, startRow, endRow, startColumn, endColumn); } /** * Get a string representation for this matrix. * @return a string representation for this matrix */ @Override public String toString() { final StringBuilder res = new StringBuilder(); String fullClassName = getClass().getName(); String shortClassName = fullClassName.substring(fullClassName.lastIndexOf('.') + 1); res.append(shortClassName); res.append(DEFAULT_FORMAT.format(this)); return res.toString(); } /** * Returns true iff <code>object</code> is a * <code>RealMatrix</code> instance with the same dimensions as this * and all corresponding matrix entries are equal. * * @param object the object to test equality against. * @return true if object equals this */ @Override public boolean equals(final Object object) { if (object == this) { return true; } if (object instanceof RealMatrix == false) { return false; } RealMatrix m = (RealMatrix) object; final int nRows = getRowDimension(); final int nCols = getColumnDimension(); if (m.getColumnDimension() != nCols || m.getRowDimension() != nRows) { return false; } for (int row = 0; row < nRows; ++row) { for (int col = 0; col < nCols; ++col) { if (getEntry(row, col) != m.getEntry(row, col)) { return false; } } } return true; } /** * Computes a hashcode for the matrix. * * @return hashcode for matrix */ @Override public int hashCode() { int ret = 7; final int nRows = getRowDimension(); final int nCols = getColumnDimension(); ret = ret * 31 + nRows; ret = ret * 31 + nCols; for (int row = 0; row < nRows; ++row) { for (int col = 0; col < nCols; ++col) { ret = ret * 31 + (11 * (row + 1) + 17 * (col + 1)) * MathUtils.hash(getEntry(row, col)); } } return ret; } /* * Empty implementations of these methods are provided in order to allow for * the use of the @Override tag with Java 1.5. */ /** {@inheritDoc} */ public abstract RealMatrix createMatrix(int rowDimension, int columnDimension) throws NotStrictlyPositiveException; /** {@inheritDoc} */ public abstract RealMatrix copy(); /** {@inheritDoc} */ public abstract double getEntry(int row, int column) throws OutOfRangeException; /** {@inheritDoc} */ public abstract void setEntry(int row, int column, double value) throws OutOfRangeException; }