quaco.js/src/utils/Complex.js

A lightweight modular Quantum Computing Simulator in JavaScript. Supports qubits, quantum gates, entanglement, circuits, algorithms, and visualization.

// src/utils/Complex.js

/**
 * Class representing a complex number a + bi.
 */
export class Complex {
    constructor(re, im) {
        this.re = re; // Real part
        this.im = im; // Imaginary part
    }

    /**
     * Adds another complex number.
     * @param {Complex} other
     * @returns {Complex}
     */
    add(other) {
        return new Complex(this.re + other.re, this.im + other.im);
    }

    /**
     * Subtracts another complex number.
     * @param {Complex} other
     * @returns {Complex}
     */
    sub(other) {
        return new Complex(this.re - other.re, this.im - other.im);
    }

    /**
     * Multiplies with another complex number.
     * @param {Complex} other
     * @returns {Complex}
     */
    mul(other) {
        return new Complex(
            this.re * other.re - this.im * other.im,
            this.re * other.im + this.im * other.re
        );
    }

    /**
     * Divides by another complex number.
     * @param {Complex} other
     * @returns {Complex}
     */
    div(other) {
        const denom = other.re * other.re + other.im * other.im;
        if (denom === 0) {
            throw new Error("Division by zero complex number");
        }
        return new Complex(
            (this.re * other.re + this.im * other.im) / denom,
            (this.im * other.re - this.re * other.im) / denom
        );
    }

    /**
     * Returns the magnitude (absolute value) of the complex number.
     * |z| = sqrt(re² + im²)
     * @returns {number}
     */
    abs() {
        return Math.sqrt(this.re * this.re + this.im * this.im);
    }

    /**
     * Returns the squared magnitude |z|² = re² + im²
     * @returns {number}
     */
    abs2() {
        return this.re * this.re + this.im * this.im;
    }

    /**
     * Returns the conjugate of the complex number.
     * @returns {Complex}
     */
    conjugate() {
        return new Complex(this.re, -this.im);
    }

    /**
     * Returns a nicely formatted string for display.
     * @returns {string}
     */
    toString() {
        const reStr = this.re.toFixed(4);
        const imStr = this.im >= 0 ? `+${this.im.toFixed(4)}i` : `${this.im.toFixed(4)}i`;
        return `${reStr}${imStr}`;
    }
}