From c7d52adf5c00e2cae9e6c21f9948259e5fadc483 Mon Sep 17 00:00:00 2001
From: Weiqun Zhang <WeiqunZhang@lbl.gov>
Date: Thu, 9 Jan 2025 18:50:58 -0800
Subject: [PATCH] Fix TerrainIF for GPU (#2056)

---
 Source/EB/ERF_InitEB.cpp  |  6 +++++-
 Source/EB/ERF_TerrainIF.H | 18 +++++-------------
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/Source/EB/ERF_InitEB.cpp b/Source/EB/ERF_InitEB.cpp
index 532879241..468addac5 100644
--- a/Source/EB/ERF_InitEB.cpp
+++ b/Source/EB/ERF_InitEB.cpp
@@ -36,7 +36,11 @@ void ERF::MakeEBGeometry()
         amrex::Print() << "\n Building EB geometry based on idealized terrain." << std::endl;
         Real dummy_time = 0.0;
         Box bx(surroundingNodes(Geom(0).Domain())); bx.grow(2);
-        FArrayBox terrain_fab(makeSlab(bx,2,0),1);
+        static FArrayBox terrain_fab;
+        if (!terrain_fab.isAllocated()) {
+            amrex::ExecOnFinalize([&] () { terrain_fab.clear(); });
+        }
+        terrain_fab.resize(makeSlab(bx,2,0),1);
         prob->init_custom_terrain(Geom(0), terrain_fab, dummy_time);
         TerrainIF ebterrain(terrain_fab, Geom(0));
         auto gshop = EB2::makeShop(ebterrain);
diff --git a/Source/EB/ERF_TerrainIF.H b/Source/EB/ERF_TerrainIF.H
index bd1222be4..def45dbcd 100644
--- a/Source/EB/ERF_TerrainIF.H
+++ b/Source/EB/ERF_TerrainIF.H
@@ -15,16 +15,10 @@ class TerrainIF
 public:
 
     TerrainIF (amrex::FArrayBox& a_z_terrain, amrex::Geometry& a_geom)
-        : m_terr(a_z_terrain),
-          m_geom(a_geom)
-        {
-            amrex::Print() << " EB type = Terrain " << std::endl;
-
-            dx = m_geom.CellSizeArray()[0];
-            dy = m_geom.CellSizeArray()[1];
-
-            terr_arr = m_terr.const_array();
-        }
+        : terr_arr(a_z_terrain.const_array()),
+          dx(a_geom.CellSize(0)),
+          dy(a_geom.CellSize(1))
+        {}
 
     AMREX_GPU_HOST_DEVICE inline
     amrex::Real operator() (AMREX_D_DECL(amrex::Real x, amrex::Real y, amrex::Real z))
@@ -36,16 +30,14 @@ public:
         return -(z - terr_arr(i,j,0));
     }
 
+    AMREX_GPU_HOST_DEVICE
     inline amrex::Real operator() (const amrex::RealArray& p) const noexcept
     {
         return this->operator() (AMREX_D_DECL(p[0], p[1], p[2]));
     }
 
 protected:
-    amrex::FArrayBox& m_terr;
     amrex::Array4<amrex::Real const> terr_arr;
-
-    amrex::Geometry&  m_geom;
     amrex::Real dx, dy;
 };