I have been running into an issue where I when I interpolate an evolved function I get nans even though there are no nans on the gridfunction itself. The nans appear to arise when the past timelevels (at iteration 0) are initialized by init_3_timelevels and occur near the buffer regions. As the evolution proceeds, these bad past timelevels are overwritten with seemingly good data.
The attached thorn demonstrates the issue by evolving the trivial system
dt_f = 1
In visit you can see nans on the “_p_p” timelevel at iteration 1 (not iteration 0??). The nans go away later in the evolution.