Re: RandomSequenceGenerator<RNG>: 'dimensionality'

Posted by Luigi Ballabio on
URL: http://quantlib.414.s1.nabble.com/RandomSequenceGenerator-RNG-dimensionality-tp913p916.html


You can define the sequence generator like you were trying to do
previously.  In this case, the dimension you'll have to pass will be the
number of steps in the path, since that's how many random numbers you'll
need to generate each path.

Luigi


On Wed, 2011-07-13 at 08:56 +0000, YuHong wrote:

>
> Thanks for the suggestion!  So I'd rather present a more important
> question:
>
> ??? usg;
> InverseCumulativeRsg<USG,InverseCumulativeNormal>   gsg( ?usg? );
>        
> In the above code, I wish to define 'gsg', an instance of class
> InverseCumulativeRsg<USG, InverseCumulativeNorma>.  'gsg' will later
> be used in PathGenerator instance for GeometricBrownianMotionProcess
> simulation.  The 'gsg' constructor needs parameter 'usg' of USG type,
> a uniformSequenceGenerator with class method 'dimension()'.  
>
> May I ask, how to define the uniformSequenceGenerator 'usg' by using
> QuantLib?  Thanks a lot!
>
> Regards,
>
> Hong Yu
>
>
>
> > Subject: Re: [Quantlib-users] RandomSequenceGenerator<RNG>:
> 'dimensionality'
> > From: [hidden email]
> > To: [hidden email]
> > CC: [hidden email]
> > Date: Wed, 13 Jul 2011 10:37:07 +0200
> >
> > On Wed, 2011-07-13 at 08:01 +0000, YuHong wrote:
> > >
> > > I am trying to create a uniformly distributed random sequence
> > > generator via the following code:
> > >
> > > srand( time(NULL) );
> > > Ranlux3UniformRng u01_rng( rand() );
> > > RandomSequenceGenerator<Ranlux3UniformRng>
> > > u01_generator( ?dimensionality?, u01_rng );
> > >
> > > In the above code line-3, I need to specify the 'dimensionality'
> > > parameter. May I ask, what does the 'dimensionality' parameter
> mean,
> > > and how to determine the correct parameter value? Thanks a lot!
> >
> > The RandomSequenceGenerator is for generating tuples (the word
> > 'sequence' might be misleading there.) The dimensionality is the
> size
> > of each tuple you want to be generated. As Obi-Wan Kenobi once said,
> > these are not the droids you're looking for.
> >
> > In your case, you can just use the Ranlux3UniformRng you
> instantiated
> > and call next() repeatedly.
> >
> > Luigi
> >
> >
> > --
> >
> > Brady's First Law of Problem Solving:
> > When confronted by a difficult problem, you can solve it more
> > easily by reducing it to the question, "How would the Lone
> > Ranger have handled this?"
> >
> >
>

--

Everything that can be invented has been invented.
-- Charles Duell, Director of U.S. Patent Office, 1899



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