[vtkusers] vtkInterpolateDataSetAttributes doesn't use InitialProblemSolver?

[tom fogal]

I was digging through vtkInterpolateDataSetAttributes to see how it was
implemented, when I noticed it (eventually) implements its own
interpolating functionality.

Basically the call tree ends up in
vtkDataSetAttributes::InterpolateTuple (well, its a vtkPointData object
but it uses the parent function) which seems to do the actual
interpolation.

I'm wondering why it doesn't use a RungeKutta2, or any other
vtkInitialProblemSolver? That would seem the natural way to implement
it to me, and I imagine produce more accurate results? The current
method seems to be a simple linear interpolation (correct me if I'm
misinterpreting)...

Perhaps RungeKutta* was developed after vtkInterpolateDataSetAttributes?

Just curious. Sorry for the long email on a frivolous implementation
detail...

-tom