complex.java

java程序包

//Below is the syntax highlighted version of Complex.java from §3.2 Creating Data Types.

/*************************************************************************
 *  Compilation:  javac Complex.java
 *  Execution:    java Complex
 *
 *  Data type for complex numbers.
 *
 *  The data type is "immutable" so once you create and initialize
 *  a complex object, you cannot change it. The "final" keyword
 *  when declaring re and im enforces this rule, making it a
 *  compile-time error to change the .re or .im fields after
 *  they've been initialized.
 *
 *  % java Complex
 *  a = a = 5.0 + 6.0i
 *  b = -3.0 + 4.0i
 *  c = -39.0 + 2.0i
 *  d = -39.0 + -2.0i
 *  e = 5.0
 *
 *************************************************************************/
package  com.biolab.node.nexTest.Jama;

public class Complex {
    private final double re;   // the real part
    private final double im;   // the imaginary part

    // create a new object with the given real and imaginary parts
    public Complex(double real, double imag) {
        re = real;
        im = imag;
    }

    // return a string representation of the invoking object
    public String toString()  { return re + ((im>=0)?"+":"") + im + "i"; }

    // return abs/modulus/magnitude and angle/phase/argument
    public double abs()   { return Math.sqrt(re*re + im*im);  }
    public double phase() { return Math.atan2(im, re);        }
    public double power() { return re*re + im*im;  }

    // return a new object whose value is (this + b)
    public Complex plus(Complex b) {
        Complex a = this;             // invoking object
        double real = a.re + b.re;
        double imag = a.im + b.im;
        Complex sum = new Complex(real, imag);
        return sum;
    }

    // return a new object whose value is (this - b)
    public Complex minus(Complex b) {
        Complex a = this;
        double real = a.re - b.re;
        double imag = a.im - b.im;
        Complex diff = new Complex(real, imag);
        return diff;
    }

    // return a new object whose value is (this * b)
    public Complex times(Complex b) {
        Complex a = this;
        double real = a.re * b.re - a.im * b.im;
        double imag = a.re * b.im + a.im * b.re;
        Complex prod = new Complex(real, imag);
        return prod;
    }

    // return a new object whose value is the conjugate of this
    public Complex conjugate() {  return new Complex(re, -im); }

    // return a new object whose value is the reciprocal of this
    public Complex reciprocal() {
        double scale = re*re + im*im;
        return new Complex(re / scale, -im / scale);
    }


    // return a / b
    public Complex divides(Complex b) {
        Complex a = this;
        return a.times(b.reciprocal());
    }

    // a static version of plus
    public static Complex plus(Complex a, Complex b) {
        double real = a.re + b.re;
        double imag = a.im + b.im;
        Complex sum = new Complex(real, imag);
        return sum;
    }


    /*
    // sample client for testing
    public static void main(String[] args) {
        Complex a = new Complex( 5.0, 6.0);
        System.out.println("a = " + a);

        Complex b = new Complex(-3.0, 4.0);
        System.out.println("b = " + b);

        Complex c = b.times(a);
        System.out.println("c = " + c);

        Complex d = c.conjugate();
        System.out.println("d = " + d);

        double e = b.abs();
        System.out.println("e = " + e);

        Complex f = a.plus(b);
        System.out.println("f = " + f);

        Complex g = Complex.plus(a, b);
        System.out.println("g = " + g);

        Complex h = a.divides(b);
        System.out.println("h = " + h);

    }
    */
}