From a77aaa758208a1998736c85d0bfb47f5e7228010 Mon Sep 17 00:00:00 2001
From: mattijs <mattijs>
Date: Mon, 17 Mar 2025 13:59:44 +0000
Subject: [PATCH] BUG: AMIInterpolation: reset cached data. Fixes #3334

---
 .../AMIInterpolation/AMIInterpolation.C       | 49 +++++++++++++++----
 1 file changed, 40 insertions(+), 9 deletions(-)

diff --git a/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C b/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
index e09bd86ffc..547112dda0 100644
--- a/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
+++ b/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2024 OpenCFD Ltd.
+    Copyright (C) 2015-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -923,6 +923,36 @@ bool Foam::AMIInterpolation::calculate
 
     addProfiling(ami, "AMIInterpolation::calculate");
 
+
+    // Clear storage (only needed if src/tgt become zero size)
+    {
+        if (srcMagSf_.size())
+        {
+            srcMagSf_.resize_nocopy(srcPatch.size());
+        }
+        srcAddress_.resize_nocopy(srcPatch.size());
+        srcWeights_.resize_nocopy(srcPatch.size());
+        srcWeightsSum_.resize_nocopy(srcPatch.size());
+        if (srcCentroids_.size())
+        {
+            srcCentroids_.resize_nocopy(srcPatch.size());
+        }
+
+        if (tgtPatch.size())
+        {
+            tgtMagSf_.resize_nocopy(tgtPatch.size());
+        }
+        tgtAddress_.resize_nocopy(tgtPatch.size());
+        tgtWeights_.resize_nocopy(tgtPatch.size());
+        tgtWeightsSum_.resize_nocopy(tgtPatch.size());
+
+        if (tgtCentroids_.size())
+        {
+            tgtCentroids_.resize_nocopy(tgtPatch.size());
+        }
+    }
+
+
     if (surfPtr)
     {
         srcPatchPts_ = srcPatch.points();
@@ -948,20 +978,13 @@ bool Foam::AMIInterpolation::calculate
     }
 
     // Note: use original communicator for statistics
-    label srcTotalSize = returnReduce
+    const label srcTotalSize = returnReduce
     (
         srcPatch.size(),
         sumOp<label>(),
         UPstream::msgType(),
         comm_
     );
-    label tgtTotalSize = returnReduce
-    (
-        tgtPatch.size(),
-        sumOp<label>(),
-        UPstream::msgType(),
-        comm_
-    );
 
     if (srcTotalSize == 0)
     {
@@ -974,6 +997,14 @@ bool Foam::AMIInterpolation::calculate
         return false;
     }
 
+    const label tgtTotalSize = returnReduce
+    (
+        tgtPatch.size(),
+        sumOp<label>(),
+        UPstream::msgType(),
+        comm_
+    );
+
     // Calculate:
     // - which processors have faces
     // - allocates a communicator (geomComm_) for those