Hook up diagnostics to `prim_advance_exp`

[mfdeakin-sandia]

This is only needed for running with CAM with diagnostics, so not critical Assigning @bartgol since he knows the most about the C++ diagnostics, but feel free to change

[bartgol]

I thought diagnostics were already hooked up... Are they not working?

[ambrad]

It's the energy diagnostics, based on elem(ie)%accum%DIFF*, which is different than the stateprint ones.

[mfdeakin-sandia]

In prim_advance_exp, we still have

#ifdef ENERGY_DIAGNOSTICS
  if (compute_diagnostics) {
    Errors::runtime_abort("'compute diagnostic' functionality not yet available in C++ build.\n",
                          Errors::err_not_implemented);
  }
#endif

and

#ifdef ENERGY_DIAGNOSTICS
  if (compute_diagnostics) {
    Errors::runtime_abort("'compute diagnostic' functionality not yet available in C++ build.\n",
                          Errors::err_not_implemented);
  }
#endif

Sorry for the lack of clarity; I don't know enough about the different types of diagnostics

[ambrad]

Also, I could be wrong, but I think this has very low priority. The diagnostic output goes into a netcdf. At some point there's likely to be a desire to have it. But it's possible, perhaps likely, that there aren't any tests for it, whether standalone or CAM. @oksanaguba might know at least about standalone HOMME.

[bartgol]

Ah, the energy diagnostics, right.