Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * #%L
 * ImgLib2: a general-purpose, multidimensional image processing library.
 * %%
 * Copyright (C) 2009 - 2015 Tobias Pietzsch, Stephan Preibisch, Barry DeZonia,
 * Stephan Saalfeld, Curtis Rueden, Albert Cardona, Christian Dietz, Jean-Yves
 * Tinevez, Johannes Schindelin, Jonathan Hale, Lee Kamentsky, Larry Lindsey, Mark
 * Hiner, Michael Zinsmaier, Martin Horn, Grant Harris, Aivar Grislis, John
 * Bogovic, Steffen Jaensch, Stefan Helfrich, Jan Funke, Nick Perry, Mark Longair,
 * Melissa Linkert and Dimiter Prodanov.
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 2 of the 
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public 
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-2.0.html>.
 * #L%
 */

public class Main {

    public static final double[] realSymetricMatrix2x2(final double ixx, final double iyy, final double ixy) {
        // Matrix: [ Ixx Ixy ; Ixy Iyy ];

        final double term = Math.sqrt((ixx - iyy) * (ixx - iyy) + 4 * ixy * ixy);

        final double mu_1 = 0.5 * (ixx + iyy + term);
        final double mu_2 = 0.5 * (ixx + iyy - term);

        if (Math.abs(iyy) > Float.MIN_VALUE) {

            final double cos = 2 * ixy;
            final double sin = iyy - ixx + term;
            final double norm = Math.sqrt(cos * cos + sin * sin);
            if (norm > Float.MIN_VALUE) {
                return new double[] { mu_1, mu_2, cos / norm, sin / norm };
            }

        }

        // Edge case logic

        // NB BDZ - cosAlpha and sinAlpha edge cases determined by comparing
        // Float.MIN_VALUE cases to values near it to see trend lines.

        double cosAlpha;
        double sinAlpha;

        // default cosAlpha and sinAlpha

        if (ixx < 0) {
            cosAlpha = 0;
            sinAlpha = 1;
        } else if (iyy >= 0) {
            if (ixy >= 0) {
                cosAlpha = 1;
                sinAlpha = 0;
            } else { // ixy < 0
                cosAlpha = -1;
                sinAlpha = 0;
            }
        } else { // iyy < 0
            if (ixy >= 0) {
                cosAlpha = 1;
                sinAlpha = 0;
            } else { // ixy < 0
                cosAlpha = -1;
                sinAlpha = 0;
            }
        }

        return new double[] { mu_1, mu_2, cosAlpha, sinAlpha };

    }
}