Merton76Process

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Merton76Process

Penschke, Walter
Hi,

I was wondering why the Merton76Process does not really adhere to the
StochasticProcess interface. I do see that there is more to this process
than a drift and a diffusion. The fact, however, that the drift and
diffusion methods for the Merton76Process are implemented via QL_FAIL, makes
it impossible to use this process in the way, a stochastic process is
supposed to be dealt with.

Would it make sense to incorporate the jump part into the diffusion method?
The diffusion would be a random variable then but at least the interface of
StochasticProcess would be satisfied.

Alternatively, one might consider to break the inheritance and to build up
the Merton76Process separately. If it does not behave like a normal
StochasticProcess, why should it be one?

Comments and thoughts on this welcome,


wpe



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Re: Merton76Process

Neil P Firth
Hello,

Lots of interesting financial models, such as variance gamma and normal
inverse gamma, are pure jump models, so any redesign should take them into
consideration. Bringing in a LevyProcess class, with drift, diffusion and
jump methods might tidy things up. However, that is quite a large
change and might cause more problems than it solves.

Neil

---------------------------------------------------
  Neil Firth
  Brasenose College Oxford OX1 4AJ United Kingdom
  Office: 01865 280616
  [hidden email]
  http://www.maths.ox.ac.uk/~firth
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RE: Merton76Process

cuchulainn
In reply to this post by Penschke, Walter
Re: [Quantlib-users] Merton76Process
Neil,
Are you doing any work on Heston sto. vol. and PIDE (not 100,000 miles (km)) away from current topic?
 
Cheers
 
Daniel
 


From: [hidden email] on behalf of Neil P Firth
Sent: Mon 13/09/2004 18:11
To: Penschke, Walter
Cc: [hidden email]
Subject: Re: [Quantlib-users] Merton76Process

Hello,

Lots of interesting financial models, such as variance gamma and normal
inverse gamma, are pure jump models, so any redesign should take them into
consideration. Bringing in a LevyProcess class, with drift, diffusion and
jump methods might tidy things up. However, that is quite a large
change and might cause more problems than it solves.

Neil

---------------------------------------------------
  Neil Firth
  Brasenose College Oxford OX1 4AJ United Kingdom
  Office: 01865 280616
  [hidden email]
  http://www.maths.ox.ac.uk/~firth
---------------------------------------------------


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RE: Merton76Process

Neil P Firth
Daniel,

No, I'm not looking at stochastic volatility. I have had a brief look at
the PIDE formulations for American option pricing on jump processes, but
I'm not working on that directly either!

Best Regards,
Neil

---------------------------------------------------
  Neil Firth
  Brasenose College Oxford OX1 4AJ United Kingdom
  [hidden email]
  http://www.maths.ox.ac.uk/~firth
---------------------------------------------------
On Mon, 13 Sep 2004, Daniel J. Duffy wrote:

> Neil,
> Are you doing any work on Heston sto. vol. and PIDE (not 100,000 miles (km)) away from current topic?
>
> Cheers
>
> Daniel
>
>
> ________________________________
>
> From: [hidden email] on behalf of Neil P Firth
> Sent: Mon 13/09/2004 18:11
> To: Penschke, Walter
> Cc: [hidden email]
> Subject: Re: [Quantlib-users] Merton76Process
>
>
>
> Hello,
>
> Lots of interesting financial models, such as variance gamma and normal
> inverse gamma, are pure jump models, so any redesign should take them into
> consideration. Bringing in a LevyProcess class, with drift, diffusion and
> jump methods might tidy things up. However, that is quite a large
> change and might cause more problems than it solves.
>
> Neil
>
> ---------------------------------------------------
>   Neil Firth
>   Brasenose College Oxford OX1 4AJ United Kingdom
>   Office: 01865 280616
>   [hidden email]
>   http://www.maths.ox.ac.uk/~firth
> ---------------------------------------------------
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by: YOU BE THE JUDGE. Be one of 170
> Project Admins to receive an Apple iPod Mini FREE for your judgement on
> who ports your project to Linux PPC the best. Sponsored by IBM.
> Deadline: Sept. 13. Go here: http://sf.net/ppc_contest.php
> _______________________________________________
> Quantlib-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/quantlib-users
>
>
>


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RE: Merton76Process

Penschke, Walter
In reply to this post by Penschke, Walter
Hello,

I agree that the implied changes are considerable. And I definitely do not
yet know all of QL!

Having put the focus so far on MC-simulation, I'd say that primarily the
PathGenerator would be involved. One idea would be to delegate (again) to
the StochasticProcess. But then - in the case of a jump diffusion process -
we also would need more than the currently available gaussian Rsg.
Presumably a Poisson-Rsg also would be required. This again violates the
current setup of the PathGenerator.

I therefore thought about creating the PathGenerator not via a gaussian
random sequence generator, but via a sequence generator factory (yet to do),
who could also create other random number sequences, e.g.: from a poisson
distribution. In the next() method of the PathGenerator this factory could
be passed over to the StochasticProcess, which in turn could sample from
(any kind of) distribution in order to simulate the process specific
behaviour (e.g.: also jumps). As a consequence there would be the need for a
new method within the StochasticProcess interface (sample()), which takes
this factory and may be other parameters and samples according to its
specific nature.

Alternatively, I could envisage a second version of the PathGenerator class
itself, which then knows how to evolve jump diffusion processes and queries
these kind of processes accordingly. This does not seem to be too nice,
because we would need an extra class. However, the existing stuff would not
be affected.

I am also not quite sure about the Path class (in MonteCarlo). Using jump
diffusion processes with MonteCarlo possibly requires a third array inside
Path, modelling the jumps. Alternatively the Path could only keep track of
the values and does not care about the individual components (drift,
diffusion, jump), which make up the values of the Path.

Comments welcome.


wpe


-----Original Message-----
From: Neil P Firth [mailto:[hidden email]]
Sent: Monday, September 13, 2004 5:11 PM
To: Penschke, Walter
Cc: [hidden email]
Subject: Re: [Quantlib-users] Merton76Process


Hello,

Lots of interesting financial models, such as variance gamma and normal
inverse gamma, are pure jump models, so any redesign should take them into
consideration. Bringing in a LevyProcess class, with drift, diffusion and
jump methods might tidy things up. However, that is quite a large
change and might cause more problems than it solves.

Neil

---------------------------------------------------
  Neil Firth
  Brasenose College Oxford OX1 4AJ United Kingdom
  Office: 01865 280616
  [hidden email]
  http://www.maths.ox.ac.uk/~firth
---------------------------------------------------