[Insight-users] segfault with itkMIRegistrationFunction -itkImageRandomIteratorWithIndex

[cyrille Valladeau]

Hello,

I am trying to use the class itkMIRegistrationFunction but an unexpected 
segfault occurs in the method ComputeUpdate() (mono channel images, size 
: 256*256).
The debugger shows me that the problem is coming from the Mercennes 
generator of the itkImageRandomIteratorWithIndex class.
I finally found 2 ways to avoid this segfault (modifing the 
itkMIRegistrationFunction::ComputeUpdate method):

- First solution:
I change the initialization value of  numberOfSamples in:

   /l.286   ImageRandomIteratorWithIndex<FixedImageType> 
randasamit(img,region);
   l.287   unsigned int numberOfSamples=20;
   l.288   randasamit.SetNumberOfSamples( numberOfSamples );/

A upper value does not change anything, but a lower one works...!!!

- Second solution:
I initialize the iterator generator seed (without changing the 
numerOfSamples):

  / l.286   ImageRandomIteratorWithIndex<FixedImageType> 
randasamit(img,region);
   l.287   unsigned int numberOfSamples=20;
   l.288   randasamit.SetNumberOfSamples( numberOfSamples );
   l.289   randasamit.ReinitializeSeed();/

Do you have any idea of what happens?
Do you think it is a real ITK bug or am I using the class in a wrong way?

Thanks,
Guillaume