Feature/pnorris/#422 #443 rrtmg lw sw combo generator

[dr0cloud]

This is a large non-zero-diff PR with fastLW+SW that tidies up RRTMG LW and SW and makes them both about 2/3 the runtime and makes them use a combined cloud generator. The changes have been discussed and vetted in modeling group over the past 2-3 months. Most changes are "statistically zero-diff" in the sense that they have minimal difference (~< 0.01 W/m2) in global TOA fluxes (in 3 month MERRA-2 replays) and minimal changes in zonal means. But any difference in the stochastic cloud generator (even changing the PRNG) will have large instantaneous changes in clouds (and therefore radiative fluxes) that will average to near-zero over space and time. The few changes that were statistically non-zero-diff have been understood as being better.

[dr0cloud]

Scott, please also merge to ORBIT default on (AGCM.rc add two lines) at or near this PR (before or after). Thanks, Peter.

[tclune]

CMake changes

[mathomp4]

@dr0cloud It looks like the GNU build has an issue:

/root/project/GEOSgcm/src/Components/@GEOSgcm_GridComp/GEOSagcm_GridComp/GEOSphysics_GridComp/GEOSradiation_GridComp/GEOS_RadiationShared/cloud_condensate_inhomogeneity.F90:95:15:

   95 |       if (.not. condensate_inhomogeneous()) then
      |               1
Error: Function 'condensate_inhomogeneous' at (1) has no IMPLICIT type

Now the function in question does seem pretty...correct:

   function condensate_inhomogeneous result (inhomo)
      logical :: inhomo
      if (.not. initialized) then
         write(error_unit,*) 'file:', __FILE__, ', line:', __LINE__
         error stop 'must initialize_inhomogeneity first'
      end if 
      inhomo = (inhm > 0)
   end function condensate_inhomogeneous

so I'm not sure why GNU is having an issue.

@tclune do you see anything wrong here? Or is this just some GNU oddity so it needs to be the uglier:

   logical function condensate_inhomogeneous()
      if (.not. initialized) then
         write(error_unit,*) 'file:', __FILE__, ', line:', __LINE__
         error stop 'must initialize_inhomogeneity first'
      end if 
      condensate_inhomogeneous = (inhm > 0)
   end function condensate_inhomogeneous

[mathomp4]

Per @Gvilla1000-nasa, he says that this might be a GNU bug. He encountered something similar with an:

  if (function()) then

where he instead had to do:

  condition = function()
  if (condition) then

GNU had some issue with doing an if-test on a function itself. (But apparently Intel and NAG were okay with doing that.)

[mathomp4]

Scott, please also merge to ORBIT default on (AGCM.rc add two lines) at or near this PR (before or after). Thanks, Peter.

@sdrabenh Just making sure you see this. @dr0cloud can you put the two lines here? Or do you have a PR in GEOSgcm_App that does it?

[sdrabenh]

Scott, please also merge to ORBIT default on (AGCM.rc add two lines) at or near this PR (before or after). Thanks, Peter.

@sdrabenh Just making sure you see this. @dr0cloud can you put the two lines here? Or do you have a PR in GEOSgcm_App that does it?

@mathomp4 and @dr0cloud I can add these changes to this PR

[dr0cloud]

@sdrabenh @mathomp4 Thanks Scott. And Matt, do we need to do anything about this GCC bug? Or can we just leave it as is?

[mathomp4]

@sdrabenh @mathomp4 Thanks Scott. And Matt, do we need to do anything about this GCC bug? Or can we just leave it as is?

@dr0cloud I'm doing some testing now to try and figure out the "right fix" to suggest you try out.

[mathomp4]

@dr0cloud Well, the solution was pretty simple. I think we just need to make:

   function condensate_inhomogeneous result (inhomo)

be:

   function condensate_inhomogeneous() result (inhomo)

For some reason, parallel make is "hiding" the real error which can be seen in serial build. When I make that change, it seems to build. I also then did a test run of GEOS (GNU Debug) and, well, nothing crashed. So that's nice.

[dr0cloud]

@mathomp4 Matt fixed it .. need "function f() result (r)" ... not "function f result (r)" for GCC. Thanks Matt!