[FLASH-USERS] ppm_modifystates: Nonconvergence in subroutine rieman

[Sean Lynch]

Hello,

I am running a simulation with a self gravitating spherically symmetric cloud in a non-equilibrium state. When allowed to run, it contracts and then rebounds and oscillates until finding the equilibrium solution.

I am using the multigrid module for gravity and gamma=5/3 equation of state. When I run this I get huge total energy errors (60%). After some testing it looks like the timestep is too large during the initial collapse and maximum compression. It seems that the timestep calculation isn't adequately taking gravity into account.

Looking through the documentation I found the runtime parameter ppm_modifystates which looks like it might fix the problem I'm having. However when I run the same exact simulation with ppm_modifystates = .TRUE. the simulation fails with "Nonconvergence in subroutine rieman"

Can someone shed some light on why setting this option would cause the simulation to fail like this?

Thanks,
Sean