This allows one to register a particle as "companion" - this particle will not be used in interpolation of fluid velocity (and the trajectory attribute will be available for other analysers that you write). Useful in simulating trajectories that start from an existing tracer data point - where you obviously have an unfair advantage in that initially your companion is very close to the simulation region.
This allows one to register a particle as "companion" - this particle will not be used in interpolation of fluid velocity (and the trajectory attribute will be available for other analysers that you write). Useful in simulating trajectories that start from an existing tracer data point - where you obviously have an unfair advantage in that initially your companion is very close to the simulation region.