// The Coding Train / Daniel Shiffman

// https://thecodingtrain.com/CodingChallenges/161-pi-from-random.html

// https://youtu.be/

​

// from Random Numbers: https://editor.p5js.org/codingtrain/sketches/FiOG6uajS

// from Digits of π: https://editor.p5js.org/codingtrain/sketches/x0eikODKm

​

let data;

let coprimeCount = 0;

let total = 0;

let index = 0;

let randomSequence = [];

​

function preload() {

  data = loadStrings('pi1000000.txt');

}

​

function setup() {

  createCanvas(400, 400);

  let digits = data[0];

  while (digits.length > 0) {

    let num = digits.slice(0, 5);

    digits = digits.slice(5);

    randomSequence.push(parseInt(num));

  }

}

​

function draw() {

  for (let n = 0; n < 500; n++) {

    let a = randomSequence[index] + 1;

    let b = randomSequence[index + 1] + 1;

    // console.log(a,b);

    if (gcd(a, b) == 1) {

      coprimeCount++;

    }

    total++;

    index += 2;

    if (index == randomSequence.length) {

      noLoop();

      console.log('complete');

      break;

    }

  }

​

  let pie = sqrt((6 * total) / coprimeCount);

​

  background(0);

  textAlign(CENTER, CENTER);

  textSize(64);

  fill(255);

  textFont('Courier');

  text(nf(pie, 1, 5), width / 2, height / 2);

​

  let w = (width * index) / randomSequence.length;

  stroke(255);

  noFill();

  rect(0, 10, width, 20);

  fill(255);

  rect(0, 10, w, 20);

}

​

function gcd(a, b) {

  if (b > a) {

    [b, a] = [a, b];

  }

​

  let r = a % b;

  if (r == 0) {

    return b;

  } else {

    return gcd(b, r);

  }

}

​