Add traits to modify HBModel and SWModel for coupling

drive shallow water model by HB model

add coupling traits, use to replace forcing traits in shallow water model

move coupling for SWModel to file in SplitExplicit

add coupling to HBModel, get fully coupled model to converge to analytic solution

Add hydrostatic spindown tests with actual multi-rate happening

remove old integral models

get flow deviation working with new reshape&broadcast setup (on cpu).

Remove stub functions for partial coupling

use Coupling trait for dispatch instead of boolean in SplitExplicitMethod.

use abbreviated model names

src/Numerics/ODESolvers/SplitExplicitMethod.jl

@@ -27,7 +27,7 @@ of the model at a faster rate than the full model. This results in a first-
 order time stepper.
 
 """ SplitExplicitSolver
-mutable struct SplitExplicitSolver{SS, FS, RT, BT, MSA} <: AbstractODESolver
+mutable struct SplitExplicitSolver{SS, FS, RT, MSA} <: AbstractODESolver
     "slow solver"
     slow_solver::SS
     "fast solver"
@@ -36,10 +36,6 @@ mutable struct SplitExplicitSolver{SS, FS, RT, BT, MSA} <: AbstractODESolver
     dt::RT
     "time"
     t::RT
-    "flag to drive fast model by slow model"
-    coupled::BT
-    "flag to reconcile slow model with fast model"
-    reconcile::BT
     "storage for transfer tendency"
     dQ2fast::MSA
 
@@ -49,25 +45,19 @@ mutable struct SplitExplicitSolver{SS, FS, RT, BT, MSA} <: AbstractODESolver
         Q = nothing;
         dt = getdt(slow_solver),
         t0 = slow_solver.t,
-        coupled = true,
-        reconcile = true,
     ) where {AT <: AbstractArray}
         SS = typeof(slow_solver)
         FS = typeof(fast_solver)
         RT = real(eltype(slow_solver.dQ))
-        BT = typeof(coupled)
-
         dQ2fast = similar(slow_solver.dQ)
         dQ2fast .= -0
         MSA = typeof(dQ2fast)
 
-        return new{SS, FS, RT, BT, MSA}(
+        return new{SS, FS, RT, MSA}(
             slow_solver,
             fast_solver,
             RT(dt),
             RT(t0),
-            coupled,
-            reconcile,
             dQ2fast,
         )
     end
@@ -102,54 +92,28 @@ function dostep!(
 
         # Initialize fast model and tendency adjustment
         # before evalution of slow mode
-        if split.coupled
-            initialize_states!(
-                slow_bl,
-                fast_bl,
-                slow.rhs!,
-                fast.rhs!,
-                Qslow,
-                Qfast,
-            )
-
-            # Evaluate the slow mode
-            # --> save tendency for the fast
-            slow.rhs!(dQ2fast, Qslow, param, slow_stage_time, increment = false)
-
-            # vertically integrate slow tendency to advance fast equation
-            # and use vertical mean for slow model (negative source)
-            # ---> work with dQ2fast as input
-            tendency_from_slow_to_fast!(
-                slow_bl,
-                fast_bl,
-                slow.rhs!,
-                fast.rhs!,
-                Qslow,
-                Qfast,
-                dQ2fast,
-                split.reconcile,
-            )
-        end
+        initialize_states!(slow_bl, fast_bl, slow.rhs!, fast.rhs!, Qslow, Qfast)
+
+        # Evaluate the slow mode
+        # --> save tendency for the fast
+        slow.rhs!(dQ2fast, Qslow, param, slow_stage_time, increment = false)
+
+        # vertically integrate slow tendency to advance fast equation
+        # and use vertical mean for slow model (negative source)
+        # ---> work with dQ2fast as input
+        tendency_from_slow_to_fast!(
+            slow_bl,
+            fast_bl,
+            slow.rhs!,
+            fast.rhs!,
+            Qslow,
+            Qfast,
+            dQ2fast,
+        )
 
         # Compute (and RK update) slow tendency
         slow.rhs!(dQslow, Qslow, param, slow_stage_time, increment = true)
 
-        # Update (RK-stage) slow state
-        event = Event(array_device(Qslow))
-        event = update!(array_device(Qslow), groupsize)(
-            realview(dQslow),
-            realview(Qslow),
-            slow.RKA[slow_s % length(slow.RKA) + 1],
-            slow.RKB[slow_s],
-            slow_dt,
-            nothing,
-            nothing,
-            nothing;
-            ndrange = length(realview(Qslow)),
-            dependencies = (event,),
-        )
-        wait(array_device(Qslow), event)
-
         # Fractional time for slow stage
         if slow_s == length(slow.RKA)
             γ = 1 - slow.RKC[slow_s]
@@ -167,31 +131,42 @@ function dostep!(
         for substep in 1:nsubsteps
             fast_time = slow_stage_time + (substep - 1) * fast_dt
             dostep!(Qfast, fast, param, fast_time)
-            if split.coupled
-                cummulate_fast_solution!(
-                    slow_bl,
-                    fast_bl,
-                    fast.rhs!,
-                    Qfast,
-                    fast_time,
-                    fast_dt,
-                    substep,
-                )
-            end
-        end
-
-        # reconcile slow equation using fast equation
-        if split.coupled
-            reconcile_from_fast_to_slow!(
+            cummulate_fast_solution!(
                 slow_bl,
                 fast_bl,
-                slow.rhs!,
                 fast.rhs!,
-                Qslow,
                 Qfast,
-                split.reconcile,
+                fast_time,
+                fast_dt,
+                substep,
             )
         end
+
+        # Update (RK-stage) slow state
+        event = Event(array_device(Qslow))
+        event = update!(array_device(Qslow), groupsize)(
+            realview(dQslow),
+            realview(Qslow),
+            slow.RKA[slow_s % length(slow.RKA) + 1],
+            slow.RKB[slow_s],
+            slow_dt,
+            nothing,
+            nothing,
+            nothing;
+            ndrange = length(realview(Qslow)),
+            dependencies = (event,),
+        )
+        wait(array_device(Qslow), event)
+
+        # reconcile slow equation using fast equation
+        reconcile_from_fast_to_slow!(
+            slow_bl,
+            fast_bl,
+            slow.rhs!,
+            fast.rhs!,
+            Qslow,
+            Qfast,
+        )
     end
     updatedt!(fast, fast_dt_in)