| /* |
| * 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.geometry.euclidean.internal; |
| |
| /** This class consists exclusively of static matrix utility methods. |
| */ |
| public final class Matrices { |
| |
| /** Private constructor. */ |
| private Matrices() {} |
| |
| /** Compute the determinant of the 2x2 matrix represented by the given values. |
| * The values are listed in row-major order. |
| * @param a00 matrix entry <code>a<sub>0,0</sub></code> |
| * @param a01 matrix entry <code>a<sub>0,1</sub></code> |
| * @param a10 matrix entry <code>a<sub>1,0</sub></code> |
| * @param a11 matrix entry <code>a<sub>1,1</sub></code> |
| * @return computed 2x2 matrix determinant |
| */ |
| public static double determinant( |
| final double a00, final double a01, |
| final double a10, final double a11) { |
| |
| return (a00 * a11) - (a01 * a10); |
| } |
| |
| /** Compute the determinant of the 3x3 matrix represented by the given values. |
| * The values are listed in row-major order. |
| * @param a00 matrix entry <code>a<sub>0,0</sub></code> |
| * @param a01 matrix entry <code>a<sub>0,1</sub></code> |
| * @param a02 matrix entry <code>a<sub>0,2</sub></code> |
| * @param a10 matrix entry <code>a<sub>1,0</sub></code> |
| * @param a11 matrix entry <code>a<sub>1,1</sub></code> |
| * @param a12 matrix entry <code>a<sub>1,2</sub></code> |
| * @param a20 matrix entry <code>a<sub>2,0</sub></code> |
| * @param a21 matrix entry <code>a<sub>2,1</sub></code> |
| * @param a22 matrix entry <code>a<sub>2,2</sub></code> |
| * @return computed 3x3 matrix determinant |
| */ |
| public static double determinant( |
| final double a00, final double a01, final double a02, |
| final double a10, final double a11, final double a12, |
| final double a20, final double a21, final double a22) { |
| |
| return ((a00 * a11 * a22) + (a01 * a12 * a20) + (a02 * a10 * a21)) - |
| ((a00 * a12 * a21) + (a01 * a10 * a22) + (a02 * a11 * a20)); |
| } |
| } |