greeks.js
function getRho(s, k, t, v, r, callPut, scale)
{
  scale = scale || 100;
  if(callPut === "call")
  {
    return _callRho(s, k, t, v, r) / scale;
  }
  else // put
  {
    return _putRho(s, k, t, v, r) / scale;
  }
}
function getRho(s, k, t, v, r, callPut, scale)
{
  scale = scale || 100;
  if(callPut === "call")
  {
    return _callRho(s, k, t, v, r) / scale;
  }
  else // put
  {
    return _putRho(s, k, t, v, r) / scale;
  }
}
function getRho ( s , k , t , v , r , callPut , scale ) { scale = scale || 100 ; if ( callPut === "call" ) { return _callRho ( s , k , t , v , r ) / scale ; } else // put { return _putRho ( s , k , t , v , r ) / scale ; } }
Calculates the rho of an 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
@param {String} callPut The type of option - "call" or "put"
@param {String} [scale=100] The value to scale rho by (100=100BPS=1%, 10000=1BPS=.01%)
@returns {Number} The rho of the option
Calculates the rho of an option .