mandelbrot5.js

class Complex {
    constructor(x, y) {
        this.x = x;
        this.y = y;
    }

    abs() {
        return Math.max(this.x * this.x, this.y * this.y);
        //return Math.sqrt(this.x * this.x, this.y * this.y);
        //return Math.hypot(this.x, this.y);
    }

    add(other) {
        this.x += other.x;
        this.y += other.y;
    }

    mul(other) {
        let newX = this.x * other.x - this.y * other.y;
        let newY = this.x * other.y + this.y * other.x;
        this.x = newX;
        this.y = newY;
    }
}

//Object.freeze(Complex);

// z(n+1) = z(n)^2 + c
function iterate_mandelbrot(c, maxIters) {
    const z = new Complex(0, 0);
    for (let i = 0; i < maxIters; i++) {
        if (z.abs() >= 2) {
            return i;
        }
        z.mul(z);
        z.add(c);
        if (i !== 0)
            quit();
    }
    return maxIters;
}

function main() {
    const start = Date.now();
    const x0 = -2.5, x1 = 1, y0 = -1, y1 = 1;
    const cols = 72, rows = 24;
    const maxIters = 1000000;


    for (let row = 0; row < rows; row++) {
        const y = (row / rows) * (y1 - y0) + y0;
        let str = '';
        for (let col = 0; col < cols; col++) {
            const x = (col / cols) * (x1 - x0) + x0;
            const c = new Complex(x, y);
            const iters = iterate_mandelbrot(c, maxIters);
            if (iters === 0) {
                str += '.';
            } else if (iters === 1) {
                str += '%';
            } else if (iters === 2) {
                str += '@';
            } else if (iters === maxIters) {
                str += ' ';
            } else {
                str += '#';
            }
        }
        console.log(str);
    }

    let end = Date.now() - start;
    console.log(end, 'milliseconds runtime');
}
main()