code: function getVega(s, k, t, v, r)
  {
    var w = bs.getW(s, k, t, v, r);
    return (isFinite(w)) ? (s * Math.sqrt(t) * _stdNormDensity(w) / 100) : 0;
  }
docs: Calculates the vega of a call and put option.
  
  @param {Number} s Current price of the underlying
  @param {Number} k Strike price
  @param {Number} t Time to experiation in years
  @param {Number} v Volatility as a decimal
  @param {Number} r Anual risk-free interest rate as a decimal
  @returns {Number} The vega of the option