On Jun 19, 2015, at 3:54 AM, Dave May <[email protected]> wrote:

I was wondering why there is different behaviour between PetscLogEventGetId() and PetscLogStageGetId()

PetscLogEventGetId() returns -1 if the event isn't found, whilst PetscLogStageGetId() throws an error if the stage isn't found.

Likely Matt had a few more beers between writing the first one and the second one.

My use case is that within one of my custom preconditioners, I wanted to call PetscLogStageRegister() during the creation phase, but obviously I can only register the stage once. To enable multiple instances of the preconditioner to exist, I need to ensure that the stage is only registered once. Hence I would like to check for the existence of the stage prior to calling the register function.

Is there currently a way to check for the existence of a registered stage?

No, we don't recommend doing it this way. The way we do it in PETSc is to have a static global variable that contains the stage ID and simply check the value of that id to determine if it has been set (set it to -1 at compile time) so your test can then just be that it is not -1. The stage register stuff goes through string comparisons so it should not be called a bunch of times. Barry

Cheers Dave