flush inpainter nan count
todo
Non-dimensionalise in pre-processor

Simple non-dimensionalisation using `scipy.ndimage.zoom`.

This method fixes the sampling interval of the non-dimensional grid but
leaves the extent free, meaning that all data is conserved. This is
important because runs with different parameters will occupy different
regions in non-dimensional space and we don't want to restrict that.
notes on non-dim map_coordinates method
notes on non-dim zoom method