BinaryCollision: implement particle creation functor (#2315)

* BinaryCollision: implement particle creation functor

* Apply suggestions from code review (restrict keyword)

Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>

* Don't restrict the particle pointers

* Use atomicSetID

* Use more restricts

* Don't use auto restrict

Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>

1 files changed, 9 insertions, 10 deletions

diff --git a/Source/Particles/Collision/BinaryCollision/ParticleCreationFunc.cpp b/Source/Particles/Collision/BinaryCollision/ParticleCreationFunc.cpp
index fff4150c1..ba6b20f1b 100644
--- a/Source/Particles/Collision/BinaryCollision/ParticleCreationFunc.cpp
+++ b/Source/Particles/Collision/BinaryCollision/ParticleCreationFunc.cpp
@@ -23,23 +23,22 @@ ParticleCreationFunc::ParticleCreationFunc (const std::string collision_name,
 
         m_collision_type = BinaryCollisionUtils::get_collision_type(collision_name, mypc);
 
-#ifdef AMREX_USE_GPU
-        amrex::Vector<int> host_num_products;
-#else
-        amrex::Gpu::DeviceVector<int>& host_num_products = m_num_products;
-#endif
         if (m_collision_type == CollisionType::ProtonBoronFusion)
             {
                 // Proton-Boron fusion only produces alpha particles
                 m_num_product_species = 1;
                 // Proton-Boron fusion produces 3 alpha particles per fusion reaction
-                host_num_products.push_back(3);
+                m_num_products_host.push_back(3);
+#ifndef AMREX_USE_GPU
+                // On CPU, the device vector can be filled immediatly
+                m_num_products_device.push_back(3);
+#endif
             }
 #ifdef AMREX_USE_GPU
-        m_num_products.resize(m_num_product_species);
-        amrex::Gpu::copyAsync(amrex::Gpu::hostToDevice, host_num_products.begin(),
-                              host_num_products.end(),
-                              m_num_products.begin());
+        m_num_products_device.resize(m_num_product_species);
+        amrex::Gpu::copyAsync(amrex::Gpu::hostToDevice, m_num_products_host.begin(),
+                              m_num_products_host.end(),
+                              m_num_products_device.begin());
         amrex::Gpu::streamSynchronize();
 #endif
     }