2D Hammersley low-discrepancy sequence

hammersley.js

function hammersley(n, bias) {
  if (isNaN(bias)) bias = (1-n)/(n+n);

  function phi2(n) {
    let r = 0;
    let b = n.toString(2);
    for (let i = 0; i < b.length; ++i) {
      if (Number(b[i])) r += 1/(1 << b.length-i);
    }
    return r;
  }

  let r = [];
  for (let i = 0; i < n; i++) {
    r.push([i/n+bias, phi2(i)+bias]);
  }
  return r;
}