core.be.tarsos.dsp.util.Complex Maven / Gradle / Ivy
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package be.tarsos.dsp.util;
/**
* Complex implements a complex number and defines complex
arithmetic and mathematical functions
Last Updated February 27, 2001
Copyright 1997-2001
@version 1.0
@author Andrew G. Bennett
* @author joren
*
*/
public class Complex {
private double x,y;
/**
Constructs the complex number z = u + i*v
@param u Real part
@param v Imaginary part
*/
public Complex(double u,double v) {
x=u;
y=v;
}
/**
Real part of this Complex number
(the x-coordinate in rectangular coordinates).
@return Re[z] where z is this Complex number.
*/
public double real() {
return x;
}
/**
Imaginary part of this Complex number
(the y-coordinate in rectangular coordinates).
@return Im[z] where z is this Complex number.
*/
public double imag() {
return y;
}
/**
Modulus of this Complex number
(the distance from the origin in polar coordinates).
@return |z| where z is this Complex number.
*/
public double mod() {
if (x!=0 || y!=0) {
return Math.sqrt(x*x+y*y);
} else {
return 0d;
}
}
/**
Argument of this Complex number
(the angle in radians with the x-axis in polar coordinates).
@return arg(z) where z is this Complex number.
*/
public double arg() {
return Math.atan2(y,x);
}
/**
Complex conjugate of this Complex number
(the conjugate of x+i*y is x-i*y).
@return z-bar where z is this Complex number.
*/
public Complex conj() {
return new Complex(x,-y);
}
/**
Addition of Complex numbers (doesn't change this Complex number).
(x+i*y) + (s+i*t) = (x+s)+i*(y+t).
@param w is the number to add.
@return z+w where z is this Complex number.
*/
public Complex plus(Complex w) {
return new Complex(x+w.real(),y+w.imag());
}
/**
Subtraction of Complex numbers (doesn't change this Complex number).
(x+i*y) - (s+i*t) = (x-s)+i*(y-t).
@param w is the number to subtract.
@return z-w where z is this Complex number.
*/
public Complex minus(Complex w) {
return new Complex(x-w.real(),y-w.imag());
}
/**
Complex multiplication (doesn't change this Complex number).
@param w is the number to multiply by.
@return z*w where z is this Complex number.
*/
public Complex times(Complex w) {
return new Complex(x*w.real()-y*w.imag(),x*w.imag()+y*w.real());
}
/**
Division of Complex numbers (doesn't change this Complex number).
(x+i*y)/(s+i*t) = ((x*s+y*t) + i*(y*s-y*t)) / (s^2+t^2)
@param w is the number to divide by
@return new Complex number z/w where z is this Complex number
*/
public Complex div(Complex w) {
double den=Math.pow(w.mod(),2);
return new Complex((x*w.real()+y*w.imag())/den,(y*w.real()-x*w.imag())/den);
}
/**
Complex exponential (doesn't change this Complex number).
@return exp(z) where z is this Complex number.
*/
public Complex exp() {
return new Complex(Math.exp(x)*Math.cos(y),Math.exp(x)*Math.sin(y));
}
/**
Principal branch of the Complex logarithm of this Complex number.
(doesn't change this Complex number).
The principal branch is the branch with -pi < arg <= pi.
@return log(z) where z is this Complex number.
*/
public Complex log() {
return new Complex(Math.log(this.mod()),this.arg());
}
/**
Complex square root (doesn't change this complex number).
Computes the principal branch of the square root, which
is the value with 0 <= arg < pi.
@return sqrt(z) where z is this Complex number.
*/
public Complex sqrt() {
double r=Math.sqrt(this.mod());
double theta=this.arg()/2;
return new Complex(r*Math.cos(theta),r*Math.sin(theta));
}
// Real cosh function (used to compute complex trig functions)
private double cosh(double theta) {
return (Math.exp(theta)+Math.exp(-theta))/2;
}
// Real sinh function (used to compute complex trig functions)
private double sinh(double theta) {
return (Math.exp(theta)-Math.exp(-theta))/2;
}
/**
Sine of this Complex number (doesn't change this Complex number).
sin(z) = (exp(i*z)-exp(-i*z))/(2*i).
@return sin(z) where z is this Complex number.
*/
public Complex sin() {
return new Complex(cosh(y)*Math.sin(x),sinh(y)*Math.cos(x));
}
/**
Cosine of this Complex number (doesn't change this Complex number).
cos(z) = (exp(i*z)+exp(-i*z))/ 2.
@return cos(z) where z is this Complex number.
*/
public Complex cos() {
return new Complex(cosh(y)*Math.cos(x),-sinh(y)*Math.sin(x));
}
/**
Hyperbolic sine of this Complex number
(doesn't change this Complex number).
sinh(z) = (exp(z)-exp(-z))/2.
@return sinh(z) where z is this Complex number.
*/
public Complex sinh() {
return new Complex(sinh(x)*Math.cos(y),cosh(x)*Math.sin(y));
}
/**
Hyperbolic cosine of this Complex number
(doesn't change this Complex number).
cosh(z) = (exp(z) + exp(-z)) / 2.
@return cosh(z) where z is this Complex number.
*/
public Complex cosh() {
return new Complex(cosh(x)*Math.cos(y),sinh(x)*Math.sin(y));
}
/**
Tangent of this Complex number (doesn't change this Complex number).
tan(z) = sin(z)/cos(z).
@return tan(z) where z is this Complex number.
*/
public Complex tan() {
return (this.sin()).div(this.cos());
}
/**
Negative of this complex number (chs stands for change sign).
This produces a new Complex number and doesn't change
this Complex number.
-(x+i*y) = -x-i*y.
@return -z where z is this Complex number.
*/
public Complex chs() {
return new Complex(-x,-y);
}
/**
String representation of this Complex number.
@return x+i*y, x-i*y, x, or i*y as appropriate.
*/
public String toString() {
if (x!=0 && y>0) {
return x+" + "+y+"i";
}
if (x!=0 && y<0) {
return x+" - "+(-y)+"i";
}
if (y==0) {
return String.valueOf(x);
}
if (x==0) {
return y+"i";
}
// shouldn't get here (unless Inf or NaN)
return x+" + i*"+y;
}
}