code: function(v) {
  			var pt = this._firstPT,
  				min = 0.000001,
  				val;
  			while (pt) {
  				val = pt.c * v + pt.s;
  				if (pt.r) {
  					val = Math.round(val);
  				} else if (val < min && val > -min) {
  					val = 0;
  				}
  				if (pt.f) {
  					pt.t[pt.p](val);
  				} else {
  					pt.t[pt.p] = val;
  				}
  				pt = pt._next;
  			}
  			if (this._target.cacheID) {
  				this._target.updateCache();
  			}
  		}
docs: called each time the values should be updated, and the ratio gets passed as the only parameter (typically it's a value between 0 and 1, but it can exceed those when using an ease like Elastic.easeOut or Back.easeOut, etc.)