[Insight-users] seg fault

[Christos Panagiotou]

dear luis

to remind: i am trying to alter the MultiResMIRegistration application 
to work with affine transformation
as i ve told i have problems of achieving the desired results so i ve 
added an observer to the optimizer using
the CommandIterationUpdate class found in the examples/registration/ *.cxx

imediately when the iterations start, i receive a seg fault
i used the ddd debugger as you ve proposed in a similar problem and got 
the following output:

-------------------------
Fixed image filename: mr1.mha
Big Endian: 0
Image Size: [256, 256, 136]
Image Spacing: [1, 1, 1]Moving image filename: ot_100x120x138.mha
Big Endian: 0
Image Size: [100, 120, 138]
Image Spacing: [1, 1, 1]Permute order: [1, 2, 0]Flip axes: [1, 0, 
0]Number of levels: 4
Fixed image shrink factors: [4, 4, 1]Moving image shrink factors: [2, 2, 
1]Number of iterations: [500, 500, 500, 500]Learning rates: [1e-04, 
1e-05, 5e-06, 1e-06]Translation scale: 350
PGM directory: pettopd

Preprocess the images ...
Need to permute: [1, 2, 0]Need to flip: [1, 0, 0]Register the images ...
--- Starting level 0
 No. Iterations: 500 Learning rate: 1e-04

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1084448096 (LWP 3010)]
0x0029051a in itk::SubjectImplementation::InvokeEvent(itk::EventObject 
const&, itk::Object*) () from /usr/local/lib/InsightToolkit/libITKCommon.so
(gdb)
----------------------------

i ve seen in a similar post that i need two instances of the optimizer 
if i want to modify the cost function during the optimization procedure

in the MultiResMIRegistration application i use the 
gradientdescentoptimizer and the learning rates change through the 
following code:

  typedef SimpleMemberCommand<Self> CommandType;
  typename CommandType::Pointer command = CommandType::New();
  command->SetCallbackFunction( this, &Self::StartNewLevel );

where the StartNewLevel method changes the learning rates

i am not sure if this has something to do about it, but i am stack with 
the seg fault and i am not sure why i am getting it...

any help would be appreciated

thanks
christos