From 934807c3cce1e0a760dca1d52861f704aab0f336 Mon Sep 17 00:00:00 2001
From: Axel Huebl <axel.huebl@plasma.ninja>
Date: Wed, 22 Nov 2023 15:47:49 -0800
Subject: [PATCH] Fix GPU Compile

---
 src/particles/CollectLost.cpp | 69 ++++++++++++++++++++---------------
 1 file changed, 39 insertions(+), 30 deletions(-)

diff --git a/src/particles/CollectLost.cpp b/src/particles/CollectLost.cpp
index 6c0700f51..18e739b1d 100644
--- a/src/particles/CollectLost.cpp
+++ b/src/particles/CollectLost.cpp
@@ -18,12 +18,42 @@
 
 namespace impactx
 {
+    struct CopyAndMarkNegative
+    {
+        static constexpr int s_index = 0; //!< index of runtime attribute in destination for position s where particle got lost
+        amrex::ParticleReal s_lost; //!< position s in meters where particle got lost
+
+        using SrcData = ImpactXParticleContainer::ParticleTileType::ConstParticleTileDataType;
+        using DstData = ImpactXParticleContainer::ParticleTileType::ParticleTileDataType;
+
+        AMREX_GPU_HOST_DEVICE
+        void operator() (DstData const &dst, SrcData const &src, int src_ip, int dst_ip) const noexcept {
+            dst.m_aos[dst_ip] = src.m_aos[src_ip];
+
+            for (int j = 0; j < SrcData::NAR; ++j)
+                dst.m_rdata[j][dst_ip] = src.m_rdata[j][src_ip];
+            for (int j = 0; j < src.m_num_runtime_real; ++j)
+                dst.m_runtime_rdata[j][dst_ip] = src.m_runtime_rdata[j][src_ip];
+
+            // unused: integer compile-time or runtime attributes
+            //for (int j = 0; j < SrcData::NAI; ++j)
+            //    dst.m_idata[j][dst_ip] = src.m_idata[j][src_ip];
+            //for (int j = 0; j < src.m_num_runtime_int; ++j)
+            //    dst.m_runtime_idata[j][dst_ip] = src.m_runtime_idata[j][src_ip];
+
+            // flip id to positive in destination
+            dst.id(dst_ip) = amrex::Math::abs(dst.id(dst_ip));
+
+            // remember the current s of the ref particle when lost
+            dst.m_runtime_rdata[s_index][dst_ip] = s_lost;
+        }
+    };
+
     void collect_lost_particles (ImpactXParticleContainer& source)
     {
         BL_PROFILE("impactX::collect_lost_particles");
 
         using SrcData = ImpactXParticleContainer::ParticleTileType::ConstParticleTileDataType;
-        using DstData = ImpactXParticleContainer::ParticleTileType::ParticleTileDataType;
 
         ImpactXParticleContainer& dest = *source.GetLostParticleContainer();
 
@@ -52,7 +82,7 @@ namespace impactx
                 if (np == 0) continue;  // no particles in source tile
 
                 // we will copy particles that were marked as lost, with a negative id
-                auto predicate = [] AMREX_GPU_HOST_DEVICE (const SrcData& src, int ip, const amrex::RandomEngine& /*engine*/) noexcept
+                auto const predicate = [] AMREX_GPU_HOST_DEVICE (const SrcData& src, int ip) noexcept
                 {
                     return src.id(ip) < 0;
                 };
@@ -64,11 +94,11 @@ namespace impactx
                 amrex::ReduceOps<amrex::ReduceOpSum> reduce_op;
                 amrex::ReduceData<int> reduce_data(reduce_op);
                 {
-                    const auto src_data = ptile_source.getConstParticleTileData();
+                    auto const src_data = ptile_source.getConstParticleTileData();
 
-                    const amrex::RandomEngine rng{};  // unused
-                    reduce_op.eval(np, reduce_data, [=] AMREX_GPU_HOST_DEVICE (int ip) {
-                        return predicate(src_data, ip, rng) ? 1 : 0;
+                    reduce_op.eval(np, reduce_data, [=] AMREX_GPU_HOST_DEVICE (int ip) noexcept
+                    {
+                        return predicate(src_data, ip);
                     });
                 }
                 int const np_to_move = amrex::get<0>(reduce_data.value());
@@ -83,35 +113,14 @@ namespace impactx
                 AMREX_ALWAYS_ASSERT(SrcData::NAI == 0);
                 AMREX_ALWAYS_ASSERT(ptile_source.NumRuntimeIntComps() == 0);
 
-                //   first runtime attribute in destination is s position when particle got lost
-                int const s_index = dest.NumRuntimeRealComps() - 1;
-                auto copy_and_mark_negative = [&s_index, &s_lost](DstData& dst, const SrcData& src, int src_ip, int dst_ip) noexcept
-                {
-                    dst.m_aos[dst_ip] = src.m_aos[src_ip];
-
-                    for (int j = 0; j < SrcData::NAR; ++j)
-                        dst.m_rdata[j][dst_ip] = src.m_rdata[j][src_ip];
-                    for (int j = 0; j < src.m_num_runtime_real; ++j)
-                        dst.m_runtime_rdata[j][dst_ip] = src.m_runtime_rdata[j][src_ip];
-
-                    // unused: integer compile-time or runtime attributes
-                    //for (int j = 0; j < SrcData::NAI; ++j)
-                    //    dst.m_idata[j][dst_ip] = src.m_idata[j][src_ip];
-                    //for (int j = 0; j < src.m_num_runtime_int; ++j)
-                    //    dst.m_runtime_idata[j][dst_ip] = src.m_runtime_idata[j][src_ip];
-
-                    // flip id to positive in destination
-                    dst.id(dst_ip) = amrex::Math::abs(dst.id(dst_ip));
-
-                    // remember the current s of the ref particle when lost
-                    dst.m_runtime_rdata[s_index][dst_ip] = s_lost;
-                };
+                //   first runtime attribute in destination is s position where particle got lost
+                AMREX_ALWAYS_ASSERT(dest.NumRuntimeRealComps() > 0);
 
                 amrex::filterAndTransformParticles(
                     ptile_dest,
                     ptile_source,
                     predicate,
-                    copy_and_mark_negative,
+                    CopyAndMarkNegative{s_lost},
                     0,
                     dst_index
                 );