| // 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 is a factory for the linear algebra package. |
| |
| * <p>This class is devoted to building the right type of matrix |
| * according to the structure of the non null elements.</p> |
| |
| * <p>This is a utility class, no instance of this class should be |
| * built, so the constructor is explicitly made private.</p> |
| |
| * @version $Id$ |
| * @author L. Maisonobe |
| |
| */ |
| |
| public class MatrixFactory { |
| /** Simple constructor. |
| * Since the class is a utility class with only static methods, the |
| * constructor is made private to prevent creating instances of this |
| * class. |
| */ |
| private MatrixFactory() { |
| } |
| |
| /** Build a matrix of the right subtype. |
| * Build the right subtype of matrix according to the structure of |
| * the non null elements of the instance. Note that the information |
| * provided does not allow to build instances of the {@link |
| * SymetricalMatrix} class. When the data corresponding to a |
| * symetrical matrix is given, this method can only build an |
| * instance of the {@link GeneralSquareMatrix} class. |
| * @param rows number of row of the matrix |
| * @param columns number of columns of the matrix |
| * @param data table of the matrix elements (stored row after row) |
| * @param lowerElements number of non null elements in the lower triangle |
| * @param upperElements number of non null elements in the upper triangle |
| * @return a matrix containing the instance |
| */ |
| public static Matrix buildMatrix(int rows, int columns, double[] data, |
| int lowerElements, int upperElements) { |
| if (rows == columns) { |
| if (lowerElements == 0 && upperElements == 0) { |
| return new DiagonalMatrix(rows, data); |
| } else if (lowerElements == 0) { |
| return new UpperTriangularMatrix(rows, data); |
| } else if (upperElements == 0) { |
| return new LowerTriangularMatrix(rows, data); |
| } else { |
| return new GeneralSquareMatrix(rows, data); |
| } |
| } |
| return new GeneralMatrix(rows, columns, data); |
| } |
| |
| /** Build a matrix of the right subtype. |
| * Build the right subtype of matrix according to the dimensions. |
| * @param rows number of row of the matrix |
| * @param columns number of columns of the matrix |
| * @param data table of the matrix elements (stored row after row) |
| * @return a matrix containing the instance |
| */ |
| public static Matrix buildMatrix(int rows, int columns, double[] data) { |
| if (rows == columns) { |
| return new GeneralSquareMatrix(rows, data); |
| } |
| return new GeneralMatrix(rows, columns, data); |
| } |
| |
| } |