From ca4963a6d78a48bc290cd7a7937354ee43bd7cfd Mon Sep 17 00:00:00 2001
From: Weiqun Zhang <weiqunzhang@lbl.gov>
Date: Fri, 25 Aug 2023 08:39:52 -0700
Subject: [PATCH] ParticleLocator: Make Assignor optional template parameter

So that it is backward compatible.
---
 Src/Particle/AMReX_ParticleLocator.H | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Src/Particle/AMReX_ParticleLocator.H b/Src/Particle/AMReX_ParticleLocator.H
index e72bc553205..f4d6301fc80 100644
--- a/Src/Particle/AMReX_ParticleLocator.H
+++ b/Src/Particle/AMReX_ParticleLocator.H
@@ -44,9 +44,9 @@ struct AssignGrid
             m_num_bins.z = amrex::max(m_num_bins.z, 1);
         }
 
-    template <typename P, typename Assignor>
+    template <typename P, typename Assignor = DefaultAssignor>
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
-    int operator() (const P& p, int nGrow=0, Assignor&& assignor = DefaultAssignor{}) const noexcept
+    int operator() (const P& p, int nGrow=0, Assignor&& assignor = Assignor{}) const noexcept
     {
         const auto iv = assignor(p, m_plo, m_dxi, m_domain);
         return this->operator()(iv, nGrow);
@@ -210,10 +210,10 @@ struct AmrAssignGrid
         : m_funcs(a_funcs), m_size(a_size)
         {}
 
-    template <typename P, typename Assignor>
+    template <typename P, typename Assignor = DefaultAssignor>
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     GpuTuple<int, int> operator() (const P& p, int lev_min=-1, int lev_max=-1, int nGrow=0,
-                                   Assignor&& assignor = DefaultAssignor{}) const noexcept
+                                   Assignor&& assignor = {}) const noexcept
     {
         lev_min = (lev_min == -1) ? 0 : lev_min;
         lev_max = (lev_max == -1) ? m_size - 1 : lev_max;