phaseField FAQ's

FAQ's

Question: Error while running Cahn-Hilliard problem in parallel in debug mode?

Cahn-Hilliard problem involves setting up random initial conditions for the composition field which are generated using std::rand. In parallel, each processor generates the initial conditions independently and because of this the values for the points at the processor sub-domain boundaries (ghost nodes) may not be the same. In debug mode, as a precautionary measure, the underlying deal.ii library has checks which require equal values being set for the ghost nodes from all the sharing processors, and this causes an Assert() function to fail and throw an Error. In release mode, this check is not done and hence the error is not reported.

So long story short, this is completely expected because of the random intial conditions. This should only be an issue in parallel debug runs, and should be all fine for serial runs and parallel release (optimized) runs.