Re: Fwd: implied vol + the greeks

Posted by Luigi Ballabio on
URL: http://quantlib.414.s1.nabble.com/Fwd-implied-vol-the-greeks-tp173p174.html

On Mon, 2011-02-07 at 09:45 +0000, [hidden email] wrote:

> 1)
> i have a question regarding the extreme values of impliedVolatility, described at http://quantlib.org/reference/class_quant_lib_1_1_vanilla_option.html#95c0837ce9c4bcc4cb9b9ff975f3bfe1
>
> there, it reads :
> Volatility impliedVolatility(
>  Real price,const boost::shared_ptr & process,
>  Real accuracy = 1.0e-4,
>  Size maxEvaluations = 100,
>  Volatility minVol = 1.0e-7,
>  Volatility maxVol = 4.0 )
>  const
>
> i am OK with all the parameters, the latest expected.
> isn't there a problem with maxVol ?  i mean wouldn't it makes sense to allow a higher volatility value ?
>
> i wrote a short piece of code, with a maxVol value = 1.0e4 . that works. but, it doesn't if i write 4.0.

4.0 means 400%, so it should work except in extreme cases.  In fact, I
tried your example without passing any of the default parameters to the
impliedVolatility method (i.e., I just pass the NPV and the process) and
I get back 0.20 as expected.  Are you sure that the code that failed is
the same code you posted?

> 2) i wrote my c++/quantlib code. i then benchmarked my results against
> the E.Haug's excel pricer (the complete guide ...).
> fortunately, my calculation results are right (cool!) expect that i
> have to divide the Rho and Vega obtained values by 100 to get Haug's
> results.
> that is a matter of % i guess, but i don't understand where/why it
> comes into play.

The greeks returned by QuantLib are the derivatives.  For instance, to
estimate how much the price will move if the rate moves by 1% (that is,
from 5% to 6%) you'll have to multiply the returned rho by 1%.  Maybe
Haug is returning the latter value already?

Luigi

--

The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" but "That's funny..."
-- Isaac Asimov



------------------------------------------------------------------------------
The modern datacenter depends on network connectivity to access resources
and provide services. The best practices for maximizing a physical server's
connectivity to a physical network are well understood - see how these
rules translate into the virtual world?
http://p.sf.net/sfu/oracle-sfdevnlfb
_______________________________________________
QuantLib-users mailing list
[hidden email]
https://lists.sourceforge.net/lists/listinfo/quantlib-users