At the moment I am calculation the gradient vector flow of a volume in a python sop which is quite slow and depends on numpy and scipy which prevents it being portable and orbolt valid ..
Has anyone worked on a vopsop or vex implementation or is it maybe already there somewhere hidden in openvdb ?? ;-)

I think I just found it.
Not hidden in openvdb, but as a microsolver ..
Gradient Vector Flow should be the same as laplacian diffusion, which should be the same as the diffusion of heat or pressure in a pyro simulation.
I think the Gas Diffuse dynamics node creates a gradient vector flow field ..