Seems reasonable, though it seems odd to have already pushed the change creating the variable and not just include it in this changeset.  I was going to comment when I saw these two reviews that they should be merged, but I was too late.

The related question that we need to resolve is: what is our naming policy for global constants?  Seems like we had this discussion recently but I forgot what the outcome was and can't find anything relevant in my old email.  Seems like we have other constants that are mixed-case with underscores (e.g., Full_System).  Another argument is that the format of an identifier shouldn't depend on whether it's a const or not, so this should really be fullSystem or isFullSystem or something like that.  This makes sense if we think that someday it won't be a constant... e.g., should it really be a per-System variable at some point?  The use case of mixed-mode simulations isn't clear, but logically that's the granularity it could go to.

Once we resolve the style issue and get the right name here, I'm OK with this.