praktikum-holons/src/holeg/power_flow/ComplexNumber.java

package holeg.power_flow;

import java.util.Objects;

public class ComplexNumber {
    public final double real;
    public final double imaginary;

    public final static ComplexNumber Zero = new ComplexNumber(0, 0);
    public final static ComplexNumber One = new ComplexNumber(1, 0);
    public final static ComplexNumber j = new ComplexNumber(0, -1);

    public ComplexNumber(double real) {
        this.real = real;
        this.imaginary = 0;
    }

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

    public static ComplexNumber fromPolar(double magnitude, double angle) {
        return new ComplexNumber(magnitude * Math.cos(angle), magnitude * Math.sin(angle));
    }

    public double lenSquared() {
        return real * real + imaginary * imaginary;
    }

    public double len() {
        return Math.sqrt(lenSquared());
    }

    public double angle() {
        return Math.atan2(imaginary, real);
    }

    public ComplexNumber add(ComplexNumber other) {
        return new ComplexNumber(real + other.real, imaginary + other.imaginary);
    }

    public ComplexNumber subtract(ComplexNumber other) {
        return new ComplexNumber(real - other.real, imaginary - other.imaginary);
    }

    public ComplexNumber multiply(double scalar) {
        return new ComplexNumber(real * scalar, imaginary * scalar);
    }

    public ComplexNumber multiply(ComplexNumber other) {
        return new ComplexNumber(real * other.real - imaginary * other.imaginary, imaginary * other.real + real * other.imaginary);
    }

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

    public ComplexNumber reciprocal() {
        return new ComplexNumber(real / lenSquared(), -imaginary / lenSquared());
    }

    public ComplexNumber divide(ComplexNumber other) {
        return multiply(other.reciprocal());
    }

    public ComplexNumber negate() {
        return new ComplexNumber(-real, -imaginary);
    }

    public boolean isZero() {
        return Math.abs(real) < 0.0001 && Math.abs(imaginary) < 0.0001;
    }

    @Override
    public String toString() {
        if (imaginary >= 0)
            return String.format("%.4f + %.4fj", real, imaginary);
        return String.format("%.4f - %.4fj", real, Math.abs(imaginary));
    }

    public static boolean isNullOrZero(ComplexNumber number) {
        return number == null || number.isZero();
    }

    public static boolean equals(ComplexNumber a, ComplexNumber b) {
        if (a == b)
            return true;
        if (a == null || b == null)
            return false;
        return a.equals(b);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        ComplexNumber that = (ComplexNumber) o;
        return Double.compare(that.real, real) == 0 && Double.compare(that.imaginary, imaginary) == 0;
    }

    @Override
    public int hashCode() {
        return Objects.hash(real, imaginary);
    }
}