From 83f795979e528447a2051a6e07fb46e1cab29cd7 Mon Sep 17 00:00:00 2001
From: Dennis Yatunin <dyatun@gmail.com>
Date: Thu, 12 Sep 2024 14:31:27 -0700
Subject: [PATCH] Add LevelPlaceholderSpace

---
 NEWS.md                 |  5 +++++
 Project.toml            |  2 +-
 src/Operators/common.jl | 19 ++++++++++++++-----
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index b3b7a4b494..b870d35f0a 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,6 +4,11 @@ ClimaCore.jl Release Notes
 main
 -------
 
+v0.14.15
+-------
+
+- Added support for mixing extruded and horizontal spaces in GPU kernels. PR [#1987](https://github.com/CliMA/ClimaCore.jl/pull/1987).
+
 v0.14.14
 -------
 
diff --git a/Project.toml b/Project.toml
index 46777dac66..106e10a491 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ClimaCore"
 uuid = "d414da3d-4745-48bb-8d80-42e94e092884"
 authors = ["CliMA Contributors <clima-software@caltech.edu>"]
-version = "0.14.14"
+version = "0.14.15"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
diff --git a/src/Operators/common.jl b/src/Operators/common.jl
index b86123e97b..8945311bb9 100644
--- a/src/Operators/common.jl
+++ b/src/Operators/common.jl
@@ -69,13 +69,21 @@ end
 
 # Functions for CUDASpectralStyle
 struct PlaceholderSpace <: Spaces.AbstractSpace end
+struct LevelPlaceholderSpace <: Spaces.AbstractSpace end
 struct CenterPlaceholderSpace <: Spaces.AbstractSpace end
 struct FacePlaceholderSpace <: Spaces.AbstractSpace end
 
-
+placeholder_space(current_space, parent_space) = current_space
 placeholder_space(current_space::T, parent_space::T) where {T} =
     PlaceholderSpace()
-placeholder_space(current_space, parent_space) = current_space
+placeholder_space(
+    current_space::Spaces.AbstractPointSpace,
+    parent_space::Spaces.AbstractFiniteDifferenceSpace,
+) = LevelPlaceholderSpace()
+placeholder_space(
+    current_space::Spaces.AbstractSpectralElementSpace,
+    parent_space::Spaces.ExtrudedFiniteDifferenceSpace,
+) = LevelPlaceholderSpace()
 placeholder_space(
     current_space::Spaces.CenterFiniteDifferenceSpace,
     parent_space::Spaces.FaceFiniteDifferenceSpace,
@@ -93,8 +101,12 @@ placeholder_space(
     parent_space::Spaces.CenterExtrudedFiniteDifferenceSpace,
 ) = FacePlaceholderSpace()
 
+@inline reconstruct_placeholder_space(current_space, parent_space) =
+    current_space
 @inline reconstruct_placeholder_space(::PlaceholderSpace, parent_space) =
     parent_space
+@inline reconstruct_placeholder_space(::LevelPlaceholderSpace, parent_space) =
+    Spaces.level(parent_space, left_idx(parent_space)) # extract arbitrary level
 @inline reconstruct_placeholder_space(
     ::CenterPlaceholderSpace,
     parent_space::Spaces.FaceFiniteDifferenceSpace,
@@ -111,9 +123,6 @@ placeholder_space(
     ::FacePlaceholderSpace,
     parent_space::Spaces.CenterExtrudedFiniteDifferenceSpace,
 ) = Spaces.FaceExtrudedFiniteDifferenceSpace(parent_space)
-@inline reconstruct_placeholder_space(current_space, parent_space) =
-    current_space
-
 
 strip_space(obj, parent_space) = obj