Estimate minimum clock resolution

mininum-clock-resolution.js

// Finds minimum resolution Δ given a set of samples which are known to be in the form of N*Δ.

function computeGCD(a, b) {
  if (!Number.isInteger(a) || !Number.isInteger(b)) {
    throw new Error('Parameters in function gcd must be integer numbers');
  }

  var r;
  while (b != 0) {
    r = a % b;
    a = b;
    b = r;
  }
  return (a < 0) ? -a : a;
}

function getSample() {
  const t1 = new MouseEvent('test1').timeStamp;
  const t2 = new MouseEvent('test2').timeStamp;
  // Add 100 to below to emulate a sampler with minimum fixed cost.
  return  Math.round((t2 - t1) * 1000);
 }

// Finds minimum resolution Δ given a set of samples which are known to be in the form of N*Δ.
function estimateMinimumResolution() {

  var min, gcd;
  for (var i = 0; i <  1e3; ++i) {
    let sample  = getSample();
    if (sample == 0) continue; // ignore zero samples

    // Assuming there is at least one sample with N=1, then taking minimum of our sample is a good
    // estimate. This breaks if for any reason this assumption is incorrect for example if event
    // construction cost is always larger than the minimum resolution Δ. In this case gcd is a
    // better estimator.
    min = min ? Math.min(min, sample) : sample;

    // Compute gCD of our samples which can estimate Δ.
    gcd = gcd ? computeGCD(gcd, sample) : sample;
  }

  console.log("Estimate using Min: ", min, " Estimate using GCD:", gcd);
  return gcd;
}

estimateMinimumResolution();