Artificial Viscosity has a problem in computation of the timestep
/scratch/elena/TestMigration/TmpArtifical_old_git
here I have made the example 3D_unperturbed_disk with an old git version
/scratch/elena/TestMigration/TmpNoArtifical_old_git
the same test withhout Artificial viscosity
the 2 take the same time and provide same results
While the actual version has some problems and computes a much smaller timestep when ArtificialViscosity is true