function equals$9(a, b) {
    return Math.abs(a - b) <= EPSILON * Math.max(1.0, Math.abs(a), Math.abs(b));
  }
Tests whether or not the arguments have approximately the same value, within an absolute
or relative tolerance of glMatrix.EPSILON (an absolute tolerance is used for values less
than or equal to 1.0, and a relative tolerance is used for larger values)

@param {Number} a The first number to test.
@param {Number} b The second number to test.
@returns {Boolean} True if the numbers are approximately equal, false otherwise.