Function elasticIn

external/.d3.js:5170–5172

(t)

  var s = Math.asin(1 / (a = Math.max(1, a))) * (p /= tau$5);

  function elasticIn(t) {
    return a * tpmt(-(--t)) * Math.sin((s - t) / p);
  }

  elasticIn.amplitude = function(a) { return custom(a, p * tau$5); };
  elasticIn.period = function(p) { return custom(a, p); };