Ability to suppress diagnostics

[RonRahaman]

Should we implement a way to suppress diagnostic messages? Currently, this includes the sanity check for volume calculations. For the disjoint communicators, I also have some diagnostics about the rank layout that I'd like to keep. But these both get pretty verbose in large-ish runs.

I'm considering either:

• A -v runtime flag
• The NDEBUG macro. This is defined by CMake for release builds. It's also understood by assert() as specified by the C++ standard. However, it doesn't appear to affect the behavior of Ensures or Expects in GSL.

I'm tending towards a -v flag.

[paulromano]

Yes, I agree that a -v flag is probably the simplest way to do this.