Re-add src/tracer/MOM_generic_tracer.F90 (#8, #21)

In mom-ocean#1664, src/tracer/MOM_generic_tracer.F90 was moved to config_src/external/GFDL_ocean_BGC/MOM_generic_tracer.F90. This was done to simplify COBALT v3 development. However, having MOM_generic_tracer.F90 in the generic_tracers codebase doesnt work when compiling generic_tracers as a library, so we maintain MOM_generic_tracer.F90 in the MOM6 codebase.

This reverts commits 2208dd7 and fcf5fff.

Author: dougiesquire

config_src/external/GFDL_ocean_BGC/FMS_coupler_util.F90

@@ -0,0 +1,45 @@
+module FMS_coupler_util
+
+use coupler_types_mod, only : coupler_2d_bc_type
+
+implicit none ; private
+
+public :: extract_coupler_values, set_coupler_values
+
+contains
+
+!> Get element and index of a boundary condition
+subroutine extract_coupler_values(BC_struc, BC_index, BC_element, array_out, ilb, jlb, &
+                                  is, ie, js, je, conversion)
+  integer,                   intent(in)  :: ilb !< Lower bounds
+  integer,                   intent(in)  :: jlb !< Lower bounds
+  real, dimension(ilb:,jlb:),intent(out) :: array_out !< The array being filled with the input values
+  type(coupler_2d_bc_type),  intent(in)  :: BC_struc !< The type from which the data is being extracted
+  integer,                   intent(in)  :: BC_index !< The boundary condition number being extracted
+  integer,                   intent(in)  :: BC_element !< The element of the boundary condition being extracted
+  integer,        optional,  intent(in)  :: is !< The i- limits of array_out to be filled
+  integer,        optional,  intent(in)  :: ie !< The i- limits of array_out to be filled
+  integer,        optional,  intent(in)  :: js !< The j- limits of array_out to be filled
+  integer,        optional,  intent(in)  :: je !< The j- limits of array_out to be filled
+  real,           optional,  intent(in)  :: conversion !< A number that every element is multiplied by
+
+  array_out(:,:) = -1.
+end subroutine extract_coupler_values
+
+!> Set element and index of a boundary condition
+subroutine set_coupler_values(array_in, BC_struc, BC_index, BC_element, ilb, jlb,&
+                              is, ie, js, je, conversion)
+  integer,                  intent(in)    :: ilb !< Lower bounds
+  integer,                  intent(in)    :: jlb !< Lower bounds
+  real, dimension(ilb:,jlb:), intent(in)  :: array_in !< The array containing the values to load into the BC
+  type(coupler_2d_bc_type), intent(inout) :: BC_struc !< The type into which the data is being loaded
+  integer,                  intent(in)    :: BC_index !< The boundary condition number being set
+  integer,                  intent(in)    :: BC_element !< The element of the boundary condition being set
+  integer,        optional, intent(in)    :: is !< The i- limits of array_out to be filled
+  integer,        optional, intent(in)    :: ie !< The i- limits of array_out to be filled
+  integer,        optional, intent(in)    :: js !< The j- limits of array_out to be filled
+  integer,        optional, intent(in)    :: je !< The j- limits of array_out to be filled
+  real,           optional, intent(in)    :: conversion !< A number that every element is multiplied by
+end subroutine set_coupler_values
+
+end module FMS_coupler_util