const I0 = 10;

const R0 = 0;

const N = S0 + I0 + R0;

const days = 100;

const beta = 1/3;

​

function calcInfected(alpha) {

  let s = S0;

  let i = I0;

  let r = R0;

  for (let t = 1; t <= days; t++) {

    const stemp = s;

    const itemp = i;

    const rtemp = r;

    s = stemp - alpha * stemp * itemp;

    i = itemp - beta * itemp + alpha * stemp * itemp;

    r = N - stemp - itemp;

  }

  print(s,i,r,alpha*N)

​

  return r+i;

}

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(255);

  for (let k = 0.5; k <= 3; k+=0.1) { 

    // print(k, calcInfected(k/N))

    calcInfected(k/N)

  }

  noLoop();

}