WARNING! rmin>rmax when running TwoPhaseFlowEngine()

[Saeed]

Hi There,
When I run the TwoPhaseFlowEngine, I will be given the Error when arrives to > TwoPhaseFlowEngine.initialization()
I guessed the grains out of the box, which I asked in the code to remove that grain, but the grains were not placed outside the box.
Also, using the lower timestep but the problem remains.
Only for large grains does not give this error.
i tested in yadedaily 2018.02b and yade_2019.01a on ubuntu 16.04

sample error:

WARNING! rmin>rmax. rmin=2.10136e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=1.75633e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=2.02999e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=1.50292e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=2.16551e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=1.67435e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=2.45035e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=2.10136e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=2.27934e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=2.02674e-05 ,rmax=1e-10
WARNING! rmin>rmax. rmin=1.51404e-05 ,rmax=1e-10