From b54665e35fd15f48bb9e8f1a22eee8add51d3cba Mon Sep 17 00:00:00 2001
From: Aaron Ridley <ridley@umich.edu>
Date: Mon, 1 Apr 2024 13:38:24 -0400
Subject: [PATCH] FEAT: fill corners and moved the function to the top

---
 src/exchange_messages.cpp | 72 ++++++++++++++++++++++-----------------
 1 file changed, 40 insertions(+), 32 deletions(-)

diff --git a/src/exchange_messages.cpp b/src/exchange_messages.cpp
index d9ceaf64..be57db04 100644
--- a/src/exchange_messages.cpp
+++ b/src/exchange_messages.cpp
@@ -27,6 +27,43 @@
 //       near the equator.
 // -----------------------------------------------------------------------------
 
+
+// -----------------------------------------------------------------------------
+// This is the main exchange messages for the neutrals.
+//   We are exchanging densities, temperatures, and velocities   
+// -----------------------------------------------------------------------------
+
+
+bool Neutrals::exchange_old(Grid &grid) {
+
+  std::string function = "Neutrals::exchange";
+  static int iFunction = -1;
+  report.enter(function, iFunction);
+
+  bool DidWork = true;
+  int64_t nGCs = grid.get_nGCs();
+
+  for (int iSpecies = 0; iSpecies < nSpecies; iSpecies++) {
+    if (species[iSpecies].DoAdvect)
+      DidWork = exchange_one_var(grid, species[iSpecies].density_scgc, false);
+  }
+
+  DidWork = exchange_one_var(grid, temperature_scgc, false);
+
+  // velocity components:
+  // reverse east across the pole:
+  DidWork = exchange_one_var(grid, velocity_vcgc[0], true);
+  // reverse north across the pole:
+  DidWork = exchange_one_var(grid, velocity_vcgc[1], true);
+  // don't reverse vertical across the pole:
+  DidWork = exchange_one_var(grid, velocity_vcgc[2], false);
+
+  report.exit(function);
+  return DidWork;
+}
+
+
+
 // -----------------------------------------------------------------------------
 // Pack variables for message passing
 //   value is variable to pack
@@ -473,38 +510,6 @@ Grid::messages_struct Grid::make_new_interconnection(int64_t iDir,
   return new_inter;
 }
 
-// -----------------------------------------------------------------------------
-//
-// -----------------------------------------------------------------------------
-
-
-bool Neutrals::exchange_old(Grid &grid) {
-
-  std::string function = "Neutrals::exchange";
-  static int iFunction = -1;
-  report.enter(function, iFunction);
-
-  bool DidWork = true;
-
-  for (int iSpecies = 0; iSpecies < nSpecies; iSpecies++) {
-    if (species[iSpecies].DoAdvect)
-      DidWork = exchange_one_var(grid, species[iSpecies].density_scgc, false);
-  }
-
-  DidWork = exchange_one_var(grid, temperature_scgc, false);
-
-  // velocity components:
-  // reverse east across the pole:
-  DidWork = exchange_one_var(grid, velocity_vcgc[0], true);
-  // reverse north across the pole:
-  DidWork = exchange_one_var(grid, velocity_vcgc[1], true);
-  // don't reverse vertical across the pole:
-  DidWork = exchange_one_var(grid, velocity_vcgc[2], false);
-
-  report.exit(function);
-  return DidWork;
-}
-
 
 /*
 // -----------------------------------------------------------------------------
@@ -994,6 +999,9 @@ bool exchange_one_var(Grid &grid,
     var_to_pass = var_scgc;
   }
 
+  // Now we fill in the corners so that we don't have zero values there:
+  fill_corners(var_to_pass, nG);
+
   report.exit(function);
   return DidWork;
 }