[Insight-developers] Uniform registration results

[Stefan Klein]

Hi,

Quite a while ago this email was sent (see below). I just noticed it while 
scrolling through some older mails.

The SPSAOptimizer still seems to use the old random generator. Could it 
also be changed to use the MersenneTwister?

Regards!
Stefan.



At 08:40 28/09/05, Blezek, Daniel J (Research) wrote:
>One problem that has plagued me for some time is the different 
>registration results from different platforms.  The problem is in the 
>Random image iterator used to draw samples from the images being 
>registered.  On Unix-like systems, drand48 is used, under Windows (as best 
>I can make out) there is a C++ implementation.  They give a different 
>sequence of random numbers, as you might expect.  This leads to different 
>minimum in the registration process.
>
>To fix this, I've changed the random iterators to use the MersenTwister 
>RNG.  Some tests fail because they are not exactly the same (registration 
>is off by < 0.1 pixels/mm).  The tests that fail are:
>
>The following tests FAILED:
>         965 - ImageRegistration4oTest (Failed)
>         972 - ImageRegistration4Test (Failed)
>         979 - ImageRegistration13Test (Failed)
>         982 - ImageRegistration16Test (Failed)
>         984 - MultiResImageRegistration1Test (Failed)
>         985 - MultiResImageRegistration2Test (Failed)
>
>I've verified the final parameters are very close to the previous 
>results.  Is there an owner of these tests?  If so, can I send a patch and 
>have you verify the results?  Otherwise I'll plan to check the code in 
>with new baseline images.
>
>Regards,
>-dan
>
>
>Daniel Blezek, PhD
>GE Global Research
>Computer Scientist
>
>T 518 387 5481
>F 518 387 6981
>D *833-5481
>E blezek at research.ge.com
>www.research.ge.com
>
>1 Research Circle
>Niskayuna, NY 12309, USA
>
>General Electric Company
>
>_______________________________________________
>Insight-developers mailing list
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