[ET Trac] #2651: New warning message for missing boundary conditions

[Samuel Cupp]

#2651: New warning message for missing boundary conditions

 Reporter: Samuel Cupp
   Status: new
Milestone: 
  Version: 
     Type: task
 Priority: minor
Component: Carpet

This commit adds a warning inside ApplyPhysicalBCsForGroupI for when variables have no boundary conditions registered. Originally, there was a _cout_ statement only if a preprocessor flag was defined. I have found that this warning helped me discover several mistakes that would have been very difficult to track down without it. The associated pull request is [here](https://bitbucket.org/eschnett/carpet/pull-requests/53/carpet-added-warning-for-non-existent).

For example, it made me realize that I never properly changed over BaikalVacuum’s BC selection to also register boundary conditions with the driver. If I had put this comment in earlier, my confusion about why the code was trying to sync\+apply BCs way too often would have been instantly solved.

  
As another example, one function in BaikalVacuum reads one group everywhere and another interior. I had both everywhere, but the interior-only one has no BCs because it is only ever read on the interior. As such, I was triggering syncs for no reason. This warning pointed me to the real problem in my simulation very quickly, and this was causing my code to sync variables 24 \(RK4 \* variables in group\) times more per iteration.

  
Finally, it led to me finding that MoL’s scheduling was trying to sync scalars \(see [Ticket #2650](https://bitbucket.org/einsteintoolkit/tickets/issues/2650/fixing-write-statements-for-mol-scalars)\). While not a performance issue like the above, this is incorrect behavior.

--
Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2651/new-warning-message-for-missing-boundary
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.einsteintoolkit.org/pipermail/trac/attachments/20220930/aedfd794/attachment.html