From 2af18d70e6d7752078c2fd6a35132dc3d19f0aa9 Mon Sep 17 00:00:00 2001
From: Sam Reeve <6740307+streeve@users.noreply.github.com>
Date: Tue, 29 Aug 2023 09:52:03 -0400
Subject: [PATCH] Calculate x+u automatically inside slice

---
 src/CabanaPD_Particles.hpp | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/CabanaPD_Particles.hpp b/src/CabanaPD_Particles.hpp
index ded0430d..f0c80227 100644
--- a/src/CabanaPD_Particles.hpp
+++ b/src/CabanaPD_Particles.hpp
@@ -88,6 +88,7 @@ class Particles<DeviceType, PMB, Dimension>
     using self_type = Particles<DeviceType, PMB, Dimension>;
     using device_type = DeviceType;
     using memory_space = typename device_type::memory_space;
+    using execution_space = typename memory_space::execution_space;
     static constexpr int dim = Dimension;
 
     // Per particle.
@@ -308,10 +309,14 @@ class Particles<DeviceType, PMB, Dimension>
     }
     auto sliceCurrentPosition()
     {
+        // Update before returning data.
+        updateCurrentPosition();
         return Cabana::slice<0>( _aosoa_y, "current_positions" );
     }
     auto sliceCurrentPosition() const
     {
+        // Update before returning data.
+        updateCurrentPosition();
         return Cabana::slice<0>( _aosoa_y, "current_positions" );
     }
     auto sliceDisplacement()
@@ -373,6 +378,22 @@ class Particles<DeviceType, PMB, Dimension>
         return Cabana::slice<0>( _aosoa_nofail, "no_fail_region" );
     }
 
+    void updateCurrentPosition()
+    {
+        // Not using slice function because this is called inside.
+        auto y = Cabana::slice<0>( _aosoa_y, "current_positions" );
+        auto x = sliceReferencePosition();
+        auto u = sliceDisplacement();
+        Kokkos::RangePolicy<execution_space> policy( 0, n_local + n_ghost );
+        auto sum_x_u = KOKKOS_LAMBDA( const std::size_t pid )
+        {
+            for ( int d = 0; d < 3; d++ )
+                y( pid, d ) = x( pid, d ) + u( pid, d );
+        };
+        Kokkos::parallel_for( "CabanaPD::CalculateCurrentPositions", policy,
+                              sum_x_u );
+    }
+
     void resize( int new_local, int new_ghost )
     {
         n_local = new_local;