From a3e6af8fcf72ee29126007f9e75b869b60b40b35 Mon Sep 17 00:00:00 2001
From: mattijs <mattijs>
Date: Thu, 22 Jun 2023 15:08:38 +0100
Subject: [PATCH] BUG: processorCyclic: cell->point interpolation. Fixes #2817

---
 .../processorCyclicPointPatchField.C          | 20 +++++++++----------
 .../processorCyclicPointPatchField.H          |  3 +++
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.C b/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.C
index 8dee733480..0554b28a9c 100644
--- a/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.C
+++ b/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.C
@@ -95,19 +95,19 @@ void Foam::processorCyclicPointPatchField<Type>::initSwapAddSeparated
 {
     if (Pstream::parRun())
     {
-        // Get internal field into correct order for opposite side
-        Field<Type> pf
+        // Get internal field into correct order for opposite side. Note use
+        // of member data buffer since using non-blocking. Could be optimised
+        // out if not using non-blocking...
+        sendBuf_ = this->patchInternalField
         (
-            this->patchInternalField
-            (
-                pField,
-                procPatch_.reverseMeshPoints()
-            )
+            pField,
+            procPatch_.reverseMeshPoints()
         );
 
         if (commsType == Pstream::commsTypes::nonBlocking)
         {
-            recvBuf_.resize_nocopy(pf.size());
+            recvBuf_.resize_nocopy(sendBuf_.size());
+
             UIPstream::read
             (
                 commsType,
@@ -122,8 +122,8 @@ void Foam::processorCyclicPointPatchField<Type>::initSwapAddSeparated
         (
             commsType,
             procPatch_.neighbProcNo(),
-            pf.cdata_bytes(),
-            pf.size_bytes(),
+            sendBuf_.cdata_bytes(),
+            sendBuf_.size_bytes(),
             procPatch_.tag(),
             procPatch_.comm()
         );
diff --git a/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.H b/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.H
index b4d5a5396a..7dd46e4f74 100644
--- a/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.H
+++ b/src/OpenFOAM/fields/pointPatchFields/constraint/processorCyclic/processorCyclicPointPatchField.H
@@ -60,6 +60,9 @@ class processorCyclicPointPatchField
         //- Local reference to processor patch
         const processorCyclicPointPatch& procPatch_;
 
+        //- Send buffer for non-blocking communication
+        mutable Field<Type> sendBuf_;
+
         //- Receive buffer for non-blocking communication
         mutable Field<Type> recvBuf_;