From 48702b48836d9aeb0db931e23ea9cc7d4ad4ccdc Mon Sep 17 00:00:00 2001
From: hengjiew <86926839+hengjiew@users.noreply.github.com>
Date: Thu, 28 Jul 2022 14:14:19 -0400
Subject: [PATCH] Let `selectActualNeighbors` return right after starting if
 there are (#2886)

no particles for communication.
---
 Src/Particle/AMReX_NeighborParticlesI.H | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Src/Particle/AMReX_NeighborParticlesI.H b/Src/Particle/AMReX_NeighborParticlesI.H
index e0c4c066a75..bcdaeebdbbf 100644
--- a/Src/Particle/AMReX_NeighborParticlesI.H
+++ b/Src/Particle/AMReX_NeighborParticlesI.H
@@ -813,6 +813,11 @@ NeighborParticleContainer<NStructReal, NStructInt, NArrayReal, NArrayInt>::
 selectActualNeighbors (CheckPair&& check_pair, int num_cells)
 {
     BL_PROFILE("NeighborParticleContainer::selectActualNeighbors");
+    const auto& geom_fine = this->Geom(0);
+    const auto& ba_fine   = this->ParticleBoxArray(0);
+    if (ba_fine.size() == 1 && !geom_fine.isAnyPeriodic()) {
+        return;
+    }
 
     for (int lev = 0; lev < this->numLevels(); ++lev)
     {