From 5e53f8db64ac4e4f1b61a28bb30107c1111d0d75 Mon Sep 17 00:00:00 2001
From: Charles Kawczynski <kawczynski.charles@gmail.com>
Date: Thu, 21 Nov 2024 09:21:26 -0500
Subject: [PATCH] Eliminate subsidence cache

---
 src/cache/cache.jl                             |  4 ----
 src/prognostic_equations/forcing/subsidence.jl | 17 +++--------------
 test/coupler_compatibility.jl                  |  1 -
 3 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/src/cache/cache.jl b/src/cache/cache.jl
index 54c0513609..dde0f73a7b 100644
--- a/src/cache/cache.jl
+++ b/src/cache/cache.jl
@@ -17,7 +17,6 @@ struct AtmosCache{
     RS,
     VS,
     PR,
-    SUB,
     LSAD,
     EXTFORCING,
     EDMFCOR,
@@ -80,7 +79,6 @@ struct AtmosCache{
     rayleigh_sponge::RS
     viscous_sponge::VS
     precipitation::PR
-    subsidence::SUB
     large_scale_advection::LSAD
     external_forcing::EXTFORCING
     edmf_coriolis::EDMFCOR
@@ -188,7 +186,6 @@ function build_cache(Y, atmos, params, surface_setup, sim_info, aerosol_names)
     rayleigh_sponge = rayleigh_sponge_cache(Y, atmos)
     viscous_sponge = viscous_sponge_cache(Y, atmos)
     precipitation = precipitation_cache(Y, atmos)
-    subsidence = subsidence_cache(Y, atmos)
     large_scale_advection = large_scale_advection_cache(Y, atmos)
     external_forcing = external_forcing_cache(Y, atmos, params)
     edmf_coriolis = edmf_coriolis_cache(Y, atmos)
@@ -217,7 +214,6 @@ function build_cache(Y, atmos, params, surface_setup, sim_info, aerosol_names)
         rayleigh_sponge,
         viscous_sponge,
         precipitation,
-        subsidence,
         large_scale_advection,
         external_forcing,
         edmf_coriolis,
diff --git a/src/prognostic_equations/forcing/subsidence.jl b/src/prognostic_equations/forcing/subsidence.jl
index 2901dadda1..11f688871c 100644
--- a/src/prognostic_equations/forcing/subsidence.jl
+++ b/src/prognostic_equations/forcing/subsidence.jl
@@ -7,26 +7,16 @@ import ClimaCore.Spaces as Spaces
 import ClimaCore.Fields as Fields
 import ClimaCore.Operators as Operators
 
-subsidence_cache(Y, atmos::AtmosModel) = subsidence_cache(Y, atmos.subsidence)
-
 #####
 ##### No subsidence
 #####
 
-subsidence_cache(Y, ::Nothing) = (;)
 subsidence_tendency!(Yₜ, Y, p, t, ::Nothing) = nothing
 
 #####
 ##### Subsidence
 #####
 
-function subsidence_cache(Y, ::Subsidence)
-    FT = Spaces.undertype(axes(Y.f))
-    return (;
-        ᶠsubsidence = similar(Y.f, FT), # TODO: fix types
-    )
-end
-
 subsidence!(ᶜρχₜ, ᶜρ, ᶠu³, ᶜχ, ::Val{:none}) =
     @. ᶜρχₜ -= ᶜρ * (ᶜsubdivᵥ(ᶠu³ * ᶠinterp(ᶜχ)) - ᶜχ * ᶜsubdivᵥ(ᶠu³))
 subsidence!(ᶜρχₜ, ᶜρ, ᶠu³, ᶜχ, ::Val{:first_order}) =
@@ -37,14 +27,13 @@ subsidence!(ᶜρχₜ, ᶜρ, ᶠu³, ᶜχ, ::Val{:third_order}) =
 function subsidence_tendency!(Yₜ, Y, p, t, ::Subsidence)
     (; moisture_model) = p.atmos
     subsidence_profile = p.atmos.subsidence.prof
-    (; ᶠsubsidence) = p.subsidence
     (; ᶜh_tot, ᶜspecific) = p.precomputed
 
-    ᶠz = Fields.coordinate_field(axes(ᶠsubsidence)).z
+    ᶠz = Fields.coordinate_field(axes(Y.f)).z
     ᶠlg = Fields.local_geometry_field(Y.f)
-    @. ᶠsubsidence = subsidence_profile(ᶠz)
     ᶠsubsidence³ = p.scratch.ᶠtemp_CT3
-    @. ᶠsubsidence³ = ᶠsubsidence * CT3(unit_basis_vector_data(CT3, ᶠlg))
+    @. ᶠsubsidence³ =
+        subsidence_profile(ᶠz) * CT3(unit_basis_vector_data(CT3, ᶠlg))
 
     # LS Subsidence
     subsidence!(Yₜ.c.ρe_tot, Y.c.ρ, ᶠsubsidence³, ᶜh_tot, Val{:first_order}())
diff --git a/test/coupler_compatibility.jl b/test/coupler_compatibility.jl
index c36201caa2..311d31313e 100644
--- a/test/coupler_compatibility.jl
+++ b/test/coupler_compatibility.jl
@@ -83,7 +83,6 @@ const T2 = 290
         p.rayleigh_sponge,
         p.viscous_sponge,
         p.precipitation,
-        p.subsidence,
         p.large_scale_advection,
         p.external_forcing,
         p.edmf_coriolis,