Select short name of variable defining ModelVerticalGrid

[pchakraborty]

Types of change(s)

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (affects only documentation or cleanup)
• Refactor (no functional changes, no api changes)

Checklist

• Tested this change with a run of GEOSgcm
• Ran the Unit Tests (make tests)

Description

• A Model VerticalGrid is now instantiated with standard_name, units and num_levels. The method add_short_names is used to specify variable short names corresponding to edge and center vertical staggerings, which is selected at runtime using the method get_short_name.
• Updated ComponentSpecParse::parse_geometry_spec to use the new interface.
• Updated Test_ModelVerticalGrid.pf to use the new interface.
• Updated vertical regridding tests to specify standard_name instead of short_name for Model VerticalGrids.
• Cleanup of FixedLevels VerticalGrid - we didn't need MAPL_BaseMod::MAPL_GridGet after all.

Related Issue

[tclune]

These cannot be hardwired here. At least not in the long term. How about requiring them in the yaml file when you try to specify the vertical grid that way:

vertical_grid:
    coordinate:
        dimension: pressure
        stagger: edge
        field: PLE
    coordinate:
        dimension: height
        stagger: center
        field: ZL
...

[pchakraborty]

Created #3184. I'll do it in a separate PR

[tclune]

Not sure that this is what we want here. It is conceivable that someone could provide just the edge and not the center. or vice versa. The center can in theory be derived from the edge (with some assumptions that appear to be nigh universal.)

It can stay for now, but be prepared for something where instead you specify name and staggerloc.

[tclune]

You need an "unusable" argument here to separate out the options. Both arguments are the same type (character), so it is dangerously ambiguous which one is intended.

[pchakraborty]

Not sure I understand. Both edge and center are optional arguments. Did you mean something like

   subroutine add_short_names(this, edge, unusable, center)
      class(ModelVerticalGrid), intent(inout) :: this
      character(*), optional, intent(in) :: edge
      class(KeywordEnforder), optional, intent(in) :: unusable
      character(*), optional, intent(in) :: center

      if (present(edge)) this%short_name_edge = edge
      if (present(center)) this%short_name_center = center
      _UNUSED_DUMMY(unusable)
   end subroutine add_short_names

[tclune]

War on nesting ... (Makes it more obvious that a final _RETURN(_SUCCESS) is not needed also)

Suggested change

	if (vertical_dim_spec == VERTICAL_DIM_EDGE) then
	short_name = this%short_name_edge
	_RETURN(_SUCCESS)
	else if (vertical_dim_spec == VERTICAL_DIM_CENTER) then
	short_name = this%short_name_center
	_RETURN(_SUCCESS)
	else
	_FAIL("unsupported vertical_dim_spec")
	end if
	if (vertical_dim_spec == VERTICAL_DIM_EDGE) then
	short_name = this%short_name_edge
	_RETURN(_SUCCESS)
	end if
	if (vertical_dim_spec == VERTICAL_DIM_CENTER) then
	short_name = this%short_name_center
	_RETURN(_SUCCESS)
	end if
	_FAIL("unsupported vertical_dim_spec")

[pchakraborty]

There is no nesting here. Also I don't see how separate if blocks is any more readable than the if/else if/else block.

[tclune]

A couple of minor changes requested. See inline comments.