¿Tiene Java una clase para números complejos?

Question

¿Tiene Java una clase para números complejos?

Answer 1

Hay un Apache Commons one llamado Complex. No creo que el JDK tenga uno.

Answer 2

Desafortunadamente, el JDK no tiene ninguna clase para números complejos.

Usted puede echar un vistazo a:

http://www.java2s.com/Code/Java/Data-Type/Thisclassrepresentscomplexnumbersanddefinesmethodsforperformingarithmeticoncomplexnumbers.htm

que proporciona una aplicación que puede ser útil.

Answer 3

No, el JDK no tiene uno pero aquí hay una implementación que he escrito.

Here es el proyecto GITHUB.

/** 
* <code>ComplexNumber</code> is a class which implements complex numbers in Java. 
* It includes basic operations that can be performed on complex numbers such as, 
* addition, subtraction, multiplication, conjugate, modulus and squaring. 
* The data type for Complex Numbers. 
* <br /><br /> 
* The features of this library include:<br /> 
* <ul> 
* <li>Arithmetic Operations (addition, subtraction, multiplication, division)</li> 
* <li>Complex Specific Operations - Conjugate, Inverse, Absolute/Magnitude, Argument/Phase</li> 
* <li>Trigonometric Operations - sin, cos, tan, cot, sec, cosec</li> 
* <li>Mathematical Functions - exp</li> 
* <li>Complex Parsing of type x+yi</li> 
* </ul> 
* 
* @author  Abdul Fatir 
* @version  1.1 
* 
*/ 
public class ComplexNumber 
{ 
    /** 
    * Used in <code>format(int)</code> to format the complex number as x+yi 
    */ 
    public static final int XY = 0; 
    /** 
    * Used in <code>format(int)</code> to format the complex number as R.cis(theta), where theta is arg(z) 
    */ 
    public static final int RCIS = 1; 
    /** 
    * The real, Re(z), part of the <code>ComplexNumber</code>. 
    */ 
    private double real; 
    /** 
    * The imaginary, Im(z), part of the <code>ComplexNumber</code>. 
    */ 
    private double imaginary; 
    /** 
    * Constructs a new <code>ComplexNumber</code> object with both real and imaginary parts 0 (z = 0 + 0i). 
    */ 
    public ComplexNumber() 
    { 
     real = 0.0; 
     imaginary = 0.0; 
    } 

    /** 
    * Constructs a new <code>ComplexNumber</code> object. 
    * @param real the real part, Re(z), of the complex number 
    * @param imaginary the imaginary part, Im(z), of the complex number 
    */ 

    public ComplexNumber(double real, double imaginary) 
    { 
     this.real = real; 
     this.imaginary = imaginary; 
    } 

    /** 
    * Adds another <code>ComplexNumber</code> to the current complex number. 
    * @param z the complex number to be added to the current complex number 
    */ 

    public void add(ComplexNumber z) 
    { 
     set(add(this,z)); 
    } 

    /** 
    * Subtracts another <code>ComplexNumber</code> from the current complex number. 
    * @param z the complex number to be subtracted from the current complex number 
    */ 

    public void subtract(ComplexNumber z) 
    { 
     set(subtract(this,z)); 
    } 

    /** 
    * Multiplies another <code>ComplexNumber</code> to the current complex number. 
    * @param z the complex number to be multiplied to the current complex number 
    */ 

    public void multiply(ComplexNumber z) 
    { 
     set(multiply(this,z)); 
    } 
    /** 
    * Divides the current <code>ComplexNumber</code> by another <code>ComplexNumber</code>. 
    * @param z the divisor 
    */ 
    public void divide(ComplexNumber z) 
    { 
     set(divide(this,z)); 
    } 
    /** 
    * Sets the value of current complex number to the passed complex number. 
    * @param z the complex number 
    */ 
    public void set(ComplexNumber z) 
    { 
     this.real = z.real; 
     this.imaginary = z.imaginary; 
    } 
    /** 
    * Adds two <code>ComplexNumber</code>. 
    * @param z1 the first <code>ComplexNumber</code>. 
    * @param z2 the second <code>ComplexNumber</code>. 
    * @return the resultant <code>ComplexNumber</code> (z1 + z2). 
    */ 
    public static ComplexNumber add(ComplexNumber z1, ComplexNumber z2) 
    { 
     return new ComplexNumber(z1.real + z2.real, z1.imaginary + z2.imaginary); 
    } 

    /** 
    * Subtracts one <code>ComplexNumber</code> from another. 
    * @param z1 the first <code>ComplexNumber</code>. 
    * @param z2 the second <code>ComplexNumber</code>. 
    * @return the resultant <code>ComplexNumber</code> (z1 - z2). 
    */ 
    public static ComplexNumber subtract(ComplexNumber z1, ComplexNumber z2) 
    { 
     return new ComplexNumber(z1.real - z2.real, z1.imaginary - z2.imaginary); 
    } 
    /** 
    * Multiplies one <code>ComplexNumber</code> to another. 
    * @param z1 the first <code>ComplexNumber</code>. 
    * @param z2 the second <code>ComplexNumber</code>. 
    * @return the resultant <code>ComplexNumber</code> (z1 * z2). 
    */ 
    public static ComplexNumber multiply(ComplexNumber z1, ComplexNumber z2) 
    { 
     double _real = z1.real*z2.real - z1.imaginary*z2.imaginary; 
     double _imaginary = z1.real*z2.imaginary + z1.imaginary*z2.real; 
     return new ComplexNumber(_real,_imaginary); 
    } 
    /** 
    * Divides one <code>ComplexNumber</code> by another. 
    * @param z1 the first <code>ComplexNumber</code>. 
    * @param z2 the second <code>ComplexNumber</code>. 
    * @return the resultant <code>ComplexNumber</code> (z1/z2). 
    */  
    public static ComplexNumber divide(ComplexNumber z1, ComplexNumber z2) 
    { 
     ComplexNumber output = multiply(z1,z2.conjugate()); 
     double div = Math.pow(z2.mod(),2); 
     return new ComplexNumber(output.real/div,output.imaginary/div); 
    } 

    /** 
    * The complex conjugate of the current complex number. 
    * @return a <code>ComplexNumber</code> object which is the conjugate of the current complex number 
    */ 

    public ComplexNumber conjugate() 
    { 
     return new ComplexNumber(this.real,-this.imaginary); 
    } 

    /** 
    * The modulus, magnitude or the absolute value of current complex number. 
    * @return the magnitude or modulus of current complex number 
    */ 

    public double mod() 
    { 
     return Math.sqrt(Math.pow(this.real,2) + Math.pow(this.imaginary,2)); 
    } 

    /** 
    * The square of the current complex number. 
    * @return a <code>ComplexNumber</code> which is the square of the current complex number. 
    */ 

    public ComplexNumber square() 
    { 
     double _real = this.real*this.real - this.imaginary*this.imaginary; 
     double _imaginary = 2*this.real*this.imaginary; 
     return new ComplexNumber(_real,_imaginary); 
    } 
    /** 
    * @return the complex number in x + yi format 
    */ 
    @Override 
    public String toString() 
    { 
     String re = this.real+""; 
     String im = ""; 
     if(this.imaginary < 0) 
      im = this.imaginary+"i"; 
     else 
      im = "+"+this.imaginary+"i"; 
     return re+im; 
    } 
    /** 
    * Calculates the exponential of the <code>ComplexNumber</code> 
    * @param z The input complex number 
    * @return a <code>ComplexNumber</code> which is e^(input z) 
    */ 
    public static ComplexNumber exp(ComplexNumber z) 
    { 
     double a = z.real; 
     double b = z.imaginary; 
     double r = Math.exp(a); 
     a = r*Math.cos(b); 
     b = r*Math.sin(b); 
     return new ComplexNumber(a,b); 
    } 
    /** 
    * Calculates the <code>ComplexNumber</code> to the passed integer power. 
    * @param z The input complex number 
    * @param power The power. 
    * @return a <code>ComplexNumber</code> which is (z)^power 
    */ 
    public static ComplexNumber pow(ComplexNumber z, int power) 
    { 
     ComplexNumber output = new ComplexNumber(z.getRe(),z.getIm()); 
     for(int i = 1; i < power; i++) 
     { 
      double _real = output.real*z.real - output.imaginary*z.imaginary; 
      double _imaginary = output.real*z.imaginary + output.imaginary*z.real; 
      output = new ComplexNumber(_real,_imaginary); 
     } 
     return output; 
    } 
    /** 
    * Calculates the sine of the <code>ComplexNumber</code> 
    * @param z the input complex number 
    * @return a <code>ComplexNumber</code> which is the sine of z. 
    */ 
    public static ComplexNumber sin(ComplexNumber z) 
    { 
     double x = Math.exp(z.imaginary); 
     double x_inv = 1/x; 
     double r = Math.sin(z.real) * (x + x_inv)/2; 
     double i = Math.cos(z.real) * (x - x_inv)/2; 
     return new ComplexNumber(r,i); 
    } 
    /** 
    * Calculates the cosine of the <code>ComplexNumber</code> 
    * @param z the input complex number 
    * @return a <code>ComplexNumber</code> which is the cosine of z. 
    */ 
    public static ComplexNumber cos(ComplexNumber z) 
    { 
     double x = Math.exp(z.imaginary); 
     double x_inv = 1/x; 
     double r = Math.cos(z.real) * (x + x_inv)/2; 
     double i = -Math.sin(z.real) * (x - x_inv)/2; 
     return new ComplexNumber(r,i); 
    } 
    /** 
    * Calculates the tangent of the <code>ComplexNumber</code> 
    * @param z the input complex number 
    * @return a <code>ComplexNumber</code> which is the tangent of z. 
    */ 
    public static ComplexNumber tan(ComplexNumber z) 
    { 
     return divide(sin(z),cos(z)); 
    } 
    /** 
    * Calculates the co-tangent of the <code>ComplexNumber</code> 
    * @param z the input complex number 
    * @return a <code>ComplexNumber</code> which is the co-tangent of z. 
    */ 
    public static ComplexNumber cot(ComplexNumber z) 
    { 
     return divide(new ComplexNumber(1,0),tan(z)); 
    } 
    /** 
    * Calculates the secant of the <code>ComplexNumber</code> 
    * @param z the input complex number 
    * @return a <code>ComplexNumber</code> which is the secant of z. 
    */ 
    public static ComplexNumber sec(ComplexNumber z) 
    { 
     return divide(new ComplexNumber(1,0),cos(z)); 
    } 
    /** 
    * Calculates the co-secant of the <code>ComplexNumber</code> 
    * @param z the input complex number 
    * @return a <code>ComplexNumber</code> which is the co-secant of z. 
    */ 
    public static ComplexNumber cosec(ComplexNumber z) 
    { 
     return divide(new ComplexNumber(1,0),sin(z)); 
    } 
    /** 
    * The real part of <code>ComplexNumber</code> 
    * @return the real part of the complex number 
    */ 
    public double getRe() 
    { 
     return this.real; 
    } 
    /** 
    * The imaginary part of <code>ComplexNumber</code> 
    * @return the imaginary part of the complex number 
    */ 
    public double getIm() 
    { 
     return this.imaginary; 
    } 
    /** 
    * The argument/phase of the current complex number. 
    * @return arg(z) - the argument of current complex number 
    */ 
    public double getArg() 
    { 
     return Math.atan2(imaginary,real); 
    } 
    /** 
    * Parses the <code>String</code> as a <code>ComplexNumber</code> of type x+yi. 
    * @param s the input complex number as string 
    * @return a <code>ComplexNumber</code> which is represented by the string. 
    */ 
    public static ComplexNumber parseComplex(String s) 
    { 
     s = s.replaceAll(" ",""); 
     ComplexNumber parsed = null; 
     if(s.contains(String.valueOf("+")) || (s.contains(String.valueOf("-")) && s.lastIndexOf('-') > 0)) 
     { 
      String re = ""; 
      String im = ""; 
      s = s.replaceAll("i",""); 
      s = s.replaceAll("I",""); 
      if(s.indexOf('+') > 0) 
      { 
       re = s.substring(0,s.indexOf('+')); 
       im = s.substring(s.indexOf('+')+1,s.length()); 
       parsed = new ComplexNumber(Double.parseDouble(re),Double.parseDouble(im)); 
      } 
      else if(s.lastIndexOf('-') > 0) 
      { 
       re = s.substring(0,s.lastIndexOf('-')); 
       im = s.substring(s.lastIndexOf('-')+1,s.length()); 
       parsed = new ComplexNumber(Double.parseDouble(re),-Double.parseDouble(im)); 
      } 
     } 
     else 
     { 
      // Pure imaginary number 
      if(s.endsWith("i") || s.endsWith("I")) 
      { 
       s = s.replaceAll("i",""); 
       s = s.replaceAll("I",""); 
       parsed = new ComplexNumber(0, Double.parseDouble(s)); 
      } 
      // Pure real number 
      else 
      { 
       parsed = new ComplexNumber(Double.parseDouble(s),0); 
      } 
     } 
     return parsed; 
    } 
    /** 
    * Checks if the passed <code>ComplexNumber</code> is equal to the current. 
    * @param z the complex number to be checked 
    * @return true if they are equal, false otherwise 
    */ 
    @Override 
    public final boolean equals(Object z) 
    { 
     if (!(z instanceof ComplexNumber)) 
      return false; 
     ComplexNumber a = (ComplexNumber) z; 
     return (real == a.real) && (imaginary == a.imaginary); 
    } 
    /** 
    * The inverse/reciprocal of the complex number. 
    * @return the reciprocal of current complex number. 
    */ 
    public ComplexNumber inverse() 
    { 
     return divide(new ComplexNumber(1,0),this); 
    } 
    /** 
    * Formats the Complex number as x+yi or r.cis(theta) 
    * @param format_id the format ID <code>ComplexNumber.XY</code> or <code>ComplexNumber.RCIS</code>. 
    * @return a string representation of the complex number 
    * @throws IllegalArgumentException if the format_id does not match. 
    */ 
    public String format(int format_id) throws IllegalArgumentException 
    { 
     String out = ""; 
     if(format_id == XY) 
      out = toString(); 
     else if(format_id == RCIS) 
     { 
      out = mod()+" cis("+getArg()+")"; 
     } 
     else 
     { 
      throw new IllegalArgumentException("Unknown Complex Number format."); 
     } 
     return out; 
    } 
}