Update SortParticlesForDeposition for pure SoA (#3277)

I also fixed a typo in the SoA particle `pos` routine that returned a
`RealVect`.

The proposed changes:
- [x] fix a bug or incorrect behavior in AMReX
- [x] add new capabilities to AMReX
- [ ] changes answers in the test suite to more than roundoff level
- [ ] are likely to significantly affect the results of downstream AMReX
users
- [ ] include documentation in the code and/or rst files, if appropriate

Src/Particle/AMReX_ParticleContainerI.H

@@ -1203,16 +1203,14 @@ ParticleContainer_impl<ParticleType, NArrayReal, NArrayInt, Allocator>
 
         for(MFIter mfi = MakeMFIter(lev); mfi.isValid(); ++mfi)
         {
-            auto& ptile           = ParticlesAt(lev, mfi);
-            auto& aos             = ptile.GetArrayOfStructs();
-            auto  pstruct_ptr     = aos().dataPtr();
-            const size_t np       = aos.numParticles();
+            const auto& ptile = ParticlesAt(lev, mfi);
+            const size_t np   = ptile.numParticles();
 
             const Box& box = mfi.validbox();
 
             using index_type = typename decltype(m_bins)::index_type;
             Gpu::DeviceVector<index_type> perm;
-            PermutationForDeposition<index_type>(perm, np, pstruct_ptr, box, geom, idx_type);
+            PermutationForDeposition<index_type>(perm, np, ptile, box, geom, idx_type);
             ReorderParticles(lev, mfi, perm.dataPtr());
         }
     }

Src/Particle/AMReX_ParticleTile.H

@@ -316,7 +316,7 @@ struct ConstSoAParticle : SoAParticleBase
     //functions to get positions of the particle in the SOA data
 
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
-    RealVect pos () const & {return RealVect(AMREX_D_DECL(this->m_constparticle_tile_data->m_rdata[0][m_index], this->m_constparticle_tile_data.m_rdata[1][m_index], this->m_constparticle_tile_data->m_rdata[2][m_index]));}
+    RealVect pos () const & {return RealVect(AMREX_D_DECL(this->m_constparticle_tile_data.m_rdata[0][m_index], this->m_constparticle_tile_data.m_rdata[1][m_index], this->m_constparticle_tile_data.m_rdata[2][m_index]));}
 
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     const RealType&  pos (int position_index) const &

Src/Particle/AMReX_ParticleUtil.H

@@ -881,9 +881,9 @@ void PermutationForDeposition (Gpu::DeviceVector<index_type>& perm, index_type n
     Gpu::Device::streamSynchronize();
 }
 
-template <class index_type, class pos_struct>
+template <class index_type, class PTile>
 void PermutationForDeposition (Gpu::DeviceVector<index_type>& perm, index_type nitems,
-                               pos_struct const* v, Box bx, Geometry geom, const IntVect idx_type)
+                               const PTile& ptile, Box bx, Geometry geom, const IntVect idx_type)
 {
     AMREX_ALWAYS_ASSERT(idx_type.allGE(IntVect(0)) && idx_type.allLE(IntVect(2)));
 
@@ -904,17 +904,21 @@ void PermutationForDeposition (Gpu::DeviceVector<index_type>& perm, index_type n
     const int ref_product = AMREX_D_TERM(refine_vect[0], * refine_vect[1], * refine_vect[2]);
     const IntVect ref_offset(AMREX_D_DECL(1, refine_vect[0], refine_vect[0] * refine_vect[1]));
 
+    auto ptd = ptile.getConstParticleTileData();
+    using ParticleType = typename PTile::ParticleType::ConstType;
     PermutationForDeposition<index_type>(perm, nitems, bx.numPts() * ref_product,
         [=] AMREX_GPU_DEVICE (index_type idx) noexcept
-        {
-            IntVect iv = ((v[idx].pos() - pos_offset) * dxi).round();
+            {
+                const auto& p = make_particle<ParticleType>{}(ptd,idx);
+
+                IntVect iv = ((p.pos() - pos_offset) * dxi).round();
 
-            IntVect iv_coarse = iv / refine_vect;
-            IntVect iv_remainder = iv - iv_coarse * refine_vect;
+                IntVect iv_coarse = iv / refine_vect;
+                IntVect iv_remainder = iv - iv_coarse * refine_vect;
 
-            iv_coarse = iv_coarse.max(bx.smallEnd());
-            iv_coarse = iv_coarse.min(bx.bigEnd());
-            return bx.index(iv_coarse) + bx.numPts() * (iv_remainder * ref_offset).sum();
+                iv_coarse = iv_coarse.max(bx.smallEnd());
+                iv_coarse = iv_coarse.min(bx.bigEnd());
+                return bx.index(iv_coarse) + bx.numPts() * (iv_remainder * ref_offset).sum();
         });
 }