complex.java

一个很好的LIBSVM的JAVA源码。对于要研究和改进SVM算法的学者。可以参考。来自数据挖掘工具YALE工具包。

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2001-2004
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.tools.math;

public class Complex implements Comparable {
    private double real, imaginary;
    public Complex(double real, double imaginary) {
	this.real = real;
	this.imaginary = imaginary;
    }
    public double getReal() { return real; }
    public double getImaginary() { return imaginary; }

    public double getLength() {
	return Math.sqrt(real*real + imaginary*imaginary);
    }

    /** Normalizes the amplitude to the correct value. <code>n</code> must be the total used size, i.e. 
     *  <code>nyquist * 2</code>. */
    public double getMagnitude(int n) {
	return (2.0d * Math.sqrt(real*real + imaginary*imaginary)) / (double)n;
    }

    public int compareTo(Object o) {
	Complex c = (Complex)o;
	return Double.compare(this.real, c.real); 
    }

    public String toString() { return "y = " + real + " + " + imaginary + " * i"; }
}