| // 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.spaceroots.mantissa.linalg; |
| |
| /** This class implements symetrical matrices of linear algebra. |
| |
| * @version $Id$ |
| * @author L. Maisonobe |
| |
| */ |
| |
| public class SymetricalMatrix |
| extends GeneralSquareMatrix { |
| |
| /** Simple constructor. |
| * This constructor builds a symetrical matrix of specified order, all |
| * elements beeing zeros. |
| * @param order order of the matrix |
| */ |
| public SymetricalMatrix(int order) { |
| super(order); |
| } |
| |
| /** Simple constructor. |
| * Build a matrix with specified elements. |
| * @param order order of the matrix |
| * @param data table of the matrix elements (stored row after row) |
| */ |
| public SymetricalMatrix(int order, double[] data) { |
| super(order, data); |
| } |
| |
| /** Copy constructor. |
| * @param s square matrix to copy |
| */ |
| public SymetricalMatrix(SymetricalMatrix s) { |
| super(s); |
| } |
| |
| /** Build the symetrical matrix resulting from the product w.A.At. |
| * @param w multiplicative factor (weight) |
| * @param a base vector used to compute the symetrical contribution |
| */ |
| public SymetricalMatrix(double w, double[] a) { |
| super(a.length, new double[a.length * a.length]); |
| |
| for (int i = 0; i < a.length; ++i) { |
| int indexU = i * (columns + 1); |
| int indexL = indexU; |
| |
| double factor = w * a[i]; |
| data[indexU] = factor * a[i]; |
| |
| for (int j = i + 1; j < columns; ++j) { |
| ++indexU; |
| indexL += columns; |
| data[indexU] = factor * a[j]; |
| data[indexL] = data[indexU]; |
| } |
| } |
| |
| } |
| |
| public Matrix duplicate() { |
| return new SymetricalMatrix(this); |
| } |
| |
| /** Set a matrix element. |
| * On symetrical matrices, setting separately elements outside of |
| * the diagonal is forbidden, so this method throws an |
| * ArrayIndexOutOfBoundsException in this case. The {@link |
| * #setElementAndSymetricalElement} can be used to set both elements |
| * simultaneously. |
| * @param i row index, from 0 to rows - 1 |
| * @param j column index, from 0 to cols - 1 |
| * @param value value of the element |
| * @exception ArrayIndexOutOfBoundsException if the indices are wrong |
| * @see #setElementAndSymetricalElement |
| * @see Matrix#getElement |
| */ |
| public void setElement(int i, int j, double value) { |
| if (i != j) { |
| throw new ArrayIndexOutOfBoundsException("cannot separately set" |
| + " elements out of diagonal" |
| + " in a symetrical matrix"); |
| } |
| super.setElement(i, j, value); |
| } |
| |
| /** Set both a matrix element and its symetrical element. |
| * @param i row index of first element (column index of second |
| * element), from 0 to order - 1 |
| * @param j column index of first element (row index of second |
| * element), from 0 to order - 1 |
| * @param value value of the elements |
| * @exception ArrayIndexOutOfBoundsException if the indices are wrong |
| * @see #setElement |
| * @see Matrix#getElement |
| */ |
| public void setElementAndSymetricalElement(int i, int j, double value) { |
| super.setElement(i, j, value); |
| if (i != j) { |
| super.setElement(j, i, value); |
| } |
| } |
| |
| /** Add a matrix to the instance. |
| * This method adds a matrix to the instance. It does modify the instance. |
| * @param s symetrical matrix to add |
| * @exception IllegalArgumentException if there is a dimension mismatch |
| */ |
| public void selfAdd(SymetricalMatrix s) { |
| |
| // validity check |
| if ((rows != s.rows) || (columns != s.columns)) { |
| throw new IllegalArgumentException("cannot add a " |
| + s.rows + 'x' + s.columns |
| + " matrix to a " |
| + rows + 'x' + columns |
| + " matrix"); |
| } |
| |
| // addition loop |
| for (int i = 0; i < rows; ++i) { |
| int indexU = i * (columns + 1); |
| int indexL = indexU; |
| |
| data[indexU] += s.data[indexU]; |
| |
| for (int j = i + 1; j < columns; ++j) { |
| ++indexU; |
| indexL += columns; |
| data[indexU] += s.data[indexU]; |
| data[indexL] = data[indexU]; |
| } |
| } |
| |
| } |
| |
| /** Substract a matrix from the instance. |
| * This method substracts a matrix from the instance. It does modify the instance. |
| * @param s symetrical matrix to substract |
| * @exception IllegalArgumentException if there is a dimension mismatch |
| */ |
| public void selfSub(SymetricalMatrix s) { |
| |
| // validity check |
| if ((rows != s.rows) || (columns != s.columns)) { |
| throw new IllegalArgumentException("cannot substract a " |
| + s.rows + 'x' + s.columns |
| + " matrix from a " |
| + rows + 'x' + columns |
| + " matrix"); |
| } |
| |
| // substraction loop |
| for (int i = 0; i < rows; ++i) { |
| int indexU = i * (columns + 1); |
| int indexL = indexU; |
| |
| data[indexU] -= s.data[indexU]; |
| |
| for (int j = i + 1; j < columns; ++j) { |
| ++indexU; |
| indexL += columns; |
| data[indexU] -= s.data[indexU]; |
| data[indexL] = data[indexU]; |
| } |
| } |
| |
| } |
| |
| /** Add the symetrical matrix resulting from the product w.A.At to the instance. |
| * This method can be used to build progressively the matrices of |
| * least square problems. The instance is modified. |
| * @param w multiplicative factor (weight) |
| * @param a base vector used to compute the symetrical contribution |
| * @exception IllegalArgumentException if there is a dimension mismatch |
| */ |
| public void selfAddWAAt(double w, double[] a) { |
| if (rows != a.length) { |
| throw new IllegalArgumentException("cannot add a " |
| + a.length + 'x' + a.length |
| + " matrix to a " |
| + rows + 'x' + columns |
| + " matrix"); |
| } |
| |
| for (int i = 0; i < rows; ++i) { |
| int indexU = i * (columns + 1); |
| int indexL = indexU; |
| |
| double factor = w * a[i]; |
| data[indexU] += factor * a[i]; |
| |
| for (int j = i + 1; j < columns; ++j) { |
| ++indexU; |
| indexL += columns; |
| data[indexU] += factor * a[j]; |
| data[indexL] = data[indexU]; |
| } |
| } |
| |
| } |
| |
| private static final long serialVersionUID = -2083829252075519221L; |
| |
| } |