[Insight-users] FW: [Vxl-maintainers] Random number generation

[Blezek, Daniel J (Research)]

Forwarded for Ian,
-dan

-----Original Message-----
From: Ian Scott [mailto:ian.m.scott at stud.man.ac.uk]
Sent: Tuesday, April 06, 2004 9:39 AM
To: Blezek, Daniel J (Research)
Cc: insight-users at itk.org; vxl-maintainers at lists.sourceforge.net
Subject: RE: [Vxl-maintainers] Random number generation


There is an RNG in vxl/contrib/mul/mbl, that we (Manchester) have been using
for many years. It has been stress tested, checked for obscure biases, etc.
http://paine.wiau.man.ac.uk/pub/doc_vxl/contrib/mul/mbl/html/classmbl__mz__r
andom.html

We could move it into vnl, if the ITK people want to share it that way.

One thing to be aware of: the C++ standards group have accepted a proposal
for random number generators to be added to the library in the next C++
standard C++0x. It is based on a design from the BOOST group, and looks
quite different from mbl_mz_random. If anyone wants some nice forward
compatibility, it might be worth porting that part of boost into vnl. Then,
when we are all using C++0x, moving from vnl_rng to std::rng would be very
easy.

Ian.

> -----Original Message-----
> From: vxl-maintainers-admin at lists.sourceforge.net
> [mailto:vxl-maintainers-admin at lists.sourceforge.net]On Behalf
> Of Blezek,
> Daniel J (Research)
> Sent: Tuesday, April 06, 2004 2:20 PM
> To: insight-users at itk.org; vxl-maintainers at lists.sourceforge.net
> Subject: [Vxl-maintainers] Random number generation
>
>
> Hi all,
>
>   I've been using the MI registration algorithm (in ITK) on
> Windows and
> Linux.  Unfortunately, even seeding the random number generator, I get
> different answers in the registration on the two platforms.
> Jim Miller and
> I tracked this down to vnl_sample, which uses drand48() if
> available, a
> built-in RNG otherwise.  I would propose that we replace
> vnl_sample with a
> consistent implementation so that cross platform code
> produces the same
> results.  Perhaps a class called itkRandomNumberGenerator?
> I'm not partial
> to any implementation, but I did find this link:
>
> http://www-personal.engin.umich.edu/~wagnerr/MersenneTwister.html
>
> The code is BSD licensed, so it shouldn't be any problem to
> incorporate into
> ITK/vxl; the original implementation is completely free of
> any licensing
> restrictions (and we could use that).
>
> Comments?
> -dan
>
> --
> Daniel Blezek, Ph.D.
> blezek at crd.ge.com
> Visualization and Computer Vision Lab, Imaging Technologies
> GE Corporate Research & Development
>
>
>
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