[MINC-users] minctracc/masking bug?

[Claude LEPAGE]

Alex,

> So far the only explanation I can think of, is that the optimizer
> follows a particular/fixed trajectory through the parameter space,
> implicitly generating an "expansion force" in a particular direction
> that can go unchecked given the right set of circumstances (a
> particular mask being one of them). Anyways, still testing different
> parameters, will report on what I find.

Can you do only 1 iteration of minctracc? Is symmetry preserved? 
Try this 1 iteration with and without smoothing (set smoothing weight
to zero). Still symmetric? 

Your suggestion above sounds like the result could be influenced by
the order of the loops. This is a common mistake in numerical analysis.
For example:
   vec[i] = some_function( vec[i-1], vec[i], vec[i+1] );
When you process vec[i+1], the value of its previous neighbour has 
changed, so running the loop forward/backward gives a different answer.
You can check the code for something like this (good luck). 

Have you tried minctracc 0.99.3? Have you tried mincreshape to change
the x,y,z ordering? I doubt this will have an impact on the results.

Claude