Improve error message CyclicBSplineDeformableTransform, "Last dimension of support size larger than the number of grid points..."

[N-Dekker]

The error message appears introduced with commit 88ca5c2, Coert Metz, 18-02-2010:

elastix/src/Components/Transforms/PeriodicBSplineTransform/itkCyclicBSplineDeformableTransform.txx

Line 54 in 88ca5c2

itkExceptionMacro( "Last dimension (" << lastDim << ") of support size ("

It appears helpful if it could have a suggestion how to fix this issue.

Maybe it should also be added to its base class, itk::AdvancedBSplineDeformableTransform

[N-Dekker]

@stefanklein Do you agree that we can make this error message clearer? Would you suggest users to make the values of GridSpacingSchedule smaller, when such an error occurs?

Do you also agree that the error message should be moved to its base class, as it applies to any bspline transform?

[stefanklein]

Hi Niels, thanks for spotting! yes the error message could be more clear indeed. In principle, the check applies to any bspline transform, but in Elastix, the user will never encounter it with the normal B-spline transform, because elastix will define the grid such that this constraint is satisfied. However, for the CyclicBSpline, in the last dimension, this constraint could be violated. I think it's not only the GridSchedule that is the relevant option, but also the FinalGridSpacing. Of course, at this level of the code, in the itk namespace, the code should not assume to be run within Elastix, so strictly speaking, we cannot give instructions in terms of Elastix parameters. Do you have a suggestion how to do solve that?
Best, Stefan