From 8ff7003d3016b9e0295150aa4f91804eb00677fc Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Sun, 5 Oct 2025 19:53:13 +0200
Subject: Center of mass calculation for grid

---
 c++/particle/geometry/circle.hpp                                    | 6 ++++++
 .../poiseulle_particles_channel_2d.cpp                              | 5 ++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/c++/particle/geometry/circle.hpp b/c++/particle/geometry/circle.hpp
index 069a1a5..ef67fdd 100644
--- a/c++/particle/geometry/circle.hpp
+++ b/c++/particle/geometry/circle.hpp
@@ -17,6 +17,7 @@ public:
 		saw::data<sch::ParticleMask<MT,2>> mask;
 
 		auto& grid = mask.template get<"grid">();
+		auto& com = mask.template get<"center_of_mass">();
 
 		//uint64_t rad_i = static_cast<uint64_t>(resolution * radius_.get())+1u;
 		uint64_t rad_i = resolution;
@@ -41,6 +42,11 @@ public:
 			}
 		}
 
+		saw::data<sch::Vector<T,2u>> com{{0,0}};
+		iterate_over([&](saw::data<saw::FixedArray<sch::UInt64,2u>>& index){
+
+		},{{0u,0u}}, grid.meta());
+
 		return mask;
 	}
 };
diff --git a/examples/poiseulle_particles_channel_2d/poiseulle_particles_channel_2d.cpp b/examples/poiseulle_particles_channel_2d/poiseulle_particles_channel_2d.cpp
index e38710a..5ae3a11 100644
--- a/examples/poiseulle_particles_channel_2d/poiseulle_particles_channel_2d.cpp
+++ b/examples/poiseulle_particles_channel_2d/poiseulle_particles_channel_2d.cpp
@@ -347,10 +347,9 @@ void couple_particles_to_lattice(
 			}
 
 			saw::data<sch::Vector<sch::T,2u>> mask_shift;
-			{
+			for(uint64_t i = 0u; i < sch::D2Q9::D; ++i){
 				// Technically rotate and adjust here
-				mask_shift.at({{0u}}) = index_shift.at({{0u}});
-				mask_shift.at({{1u}}) = index_shift.at({{1u}});
+				mask_shift.at({{i}}) = index_shift.at({{i}});
 			}
 
 			auto p_pos_lie = p_pos + mask_shift;
-- 
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