[Insight-users] Running multilevel image registration

[motes motes]

I run a multi-level image registration process using the
BSplineDeformableTransform on a 3D image volume.

In the first level I run with 6*6*6 nodes. In the second level I run
with 8*8*8 nodes and in the last level I run with 12*12*12

 Each level is run for 10 iterations (I know the is very low but I am
currently in a testing phase).

Now when it gets to the third level (12*12*12) the time used is around
40 seconds. But if I start with the 12*12*12 cube it only takes around
8 seconds.

Any ideas on what might be the reason that the 12*12*12 level takes
longer time when executed last? I have checked that data is not
duplicated or allocated twice anywhere.