From abd0dbdca5735a8281e5df27181cc08ec51dae54 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Thu, 19 Feb 2026 18:14:39 +0100
Subject: Proper distribution

---
 examples/poiseulle_3d_gpu/sim.cpp | 10 ++++---
 lib/core/c++/collision.hpp        |  9 ++++--
 lib/core/c++/descriptor.hpp       | 58 +++++++++++++++++++++++++--------------
 lib/core/tests/memory.cpp         |  4 +--
 4 files changed, 52 insertions(+), 29 deletions(-)

diff --git a/examples/poiseulle_3d_gpu/sim.cpp b/examples/poiseulle_3d_gpu/sim.cpp
index 624566f..df4647e 100644
--- a/examples/poiseulle_3d_gpu/sim.cpp
+++ b/examples/poiseulle_3d_gpu/sim.cpp
@@ -59,6 +59,7 @@ using MacroStruct = Struct<
 
 template<typename T, typename Desc>
 saw::error_or<void> setup_initial_conditions(
+		converter<T>& conv,
 		saw::data<sch::ChunkStruct<T,Desc>>& fields,
 		saw::data<sch::MacroStruct<T,Desc>>& macros,
 		saw::data<sch::FixedArray<sch::Particle<T,Desc::D>, particle_size>>& particles
@@ -148,6 +149,7 @@ saw::error_or<void> setup_initial_conditions(
 
 template<typename T, typename Desc>
 saw::error_or<void> step(
+		converter<T>& conv,
 		saw::data<sch::Ptr<sch::ChunkStruct<T,Desc>>,encode::Sycl<saw::encode::Native>>& fields,
 		saw::data<sch::Ptr<sch::MacroStruct<T,Desc>>,encode::Sycl<saw::encode::Native>>& macros,
 		saw::data<sch::UInt64> t_i,
@@ -159,7 +161,7 @@ saw::error_or<void> step(
 	// auto coll_ev = 
 	q.submit([&](acpp::sycl::handler& h){
 		// Need nicer things to handle the flow. I see improvement here
-		component<T,Desc,cmpt::BGK, encode::Sycl<saw::encode::Native>> collision{0.6};
+		component<T,Desc,cmpt::BGK, encode::Sycl<saw::encode::Native>> collision{conv.template kinematic_viscosity_si_to_tau<Desc>({0.1}).handle()};
 		// component<T,Desc,cmpt::HLBM,encode::Sycl<saw::encode::Native>> collision{0.6};
 		component<T,Desc,cmpt::BounceBack,encode::Sycl<saw::encode::Native>> bb;
 
@@ -255,7 +257,7 @@ saw::error_or<void> lbm_main(int argc, char** argv){
 	}
 	auto& lbm_dir = eo_lbm_dir.get_value();
 
-	auto out_dir = lbm_dir / "poiseulle_particles_3d_gpu";
+	auto out_dir = lbm_dir / "poiseulle_3d_gpu";
 
 	{
 		std::error_code ec;
@@ -302,7 +304,7 @@ saw::error_or<void> lbm_main(int argc, char** argv){
 
 	sycl_q.wait();
 	{
-		auto eov = setup_initial_conditions<T,Desc>(*lbm_data_ptr,*lbm_macro_data_ptr,*lbm_particle_data_ptr);
+		auto eov = setup_initial_conditions<T,Desc>(conv,*lbm_data_ptr,*lbm_macro_data_ptr,*lbm_particle_data_ptr);
 		if(eov.is_error()){
 			return eov;
 		}
@@ -355,7 +357,7 @@ saw::error_or<void> lbm_main(int argc, char** argv){
 			}*/
 		}
 		{
-			auto eov = step<T,Desc>(lsd_view,lsdm_view,i,dev);
+			auto eov = step<T,Desc>(conv,lsd_view,lsdm_view,i,dev);
 			if(eov.is_error()){
 				return eov;
 			}
diff --git a/lib/core/c++/collision.hpp b/lib/core/c++/collision.hpp
index 349833f..f259c9f 100644
--- a/lib/core/c++/collision.hpp
+++ b/lib/core/c++/collision.hpp
@@ -18,12 +18,17 @@ struct BGKGuo {};
 template<typename T, typename Descriptor, typename Encode>
 class component<T, Descriptor, cmpt::BGK, Encode> {
 private:
-	typename saw::native_data_type<T>::type relaxation_;
+	saw::data<T> relaxation_;
 	saw::data<T> frequency_;
 public:
 	component(typename saw::native_data_type<T>::type relaxation__):
+		relaxation_{{relaxation__}},
+		frequency_{saw::data<T>{1} / relaxation_}
+	{}
+	
+	component(const saw::data<T>& relaxation__):
 		relaxation_{relaxation__},
-		frequency_{typename saw::native_data_type<T>::type(1) / relaxation_}
+		frequency_{saw::data<T>{1} / relaxation_}
 	{}
 
 	using Component = cmpt::BGK;
diff --git a/lib/core/c++/descriptor.hpp b/lib/core/c++/descriptor.hpp
index e38daee..73f0cce 100644
--- a/lib/core/c++/descriptor.hpp
+++ b/lib/core/c++/descriptor.hpp
@@ -54,6 +54,22 @@ struct CellFieldStruct {
 template<typename T, typename Desc>
 class df_info{};
 
+/*
+namespace impl {
+template<typename Desc>
+struct df_ct_helper {
+	template<uint64_t i>
+	static constexpr uint64_t apply_i(const std::array<std::array<int32_t,Desc::D>,Desc::Q>& dirs, const std::array<T,Desc::D+1u>& inp){
+		if constexpr ( i < Desc::Q ){
+			for(uint64_t j = 0u; j < Desc::D; ++j){
+			}
+		}
+		return 0u;
+	}
+};
+}
+*/
+
 template<typename T> 
 class df_info<T,sch::Descriptor<1,3>> {
 public:
@@ -214,34 +230,34 @@ public:
 	static constexpr std::array<typename saw::native_data_type<T>::type,Q> weights = {
 		8./27.,
 		// 1D
-		2./27.,
-		2./27.,
-		// 2D
-		2./27.,
-		1./9.,
 		1./36.,
 		1./36.,
+		// 2D
 		1./36.,
+		1./54.,
+		1./54.,
 		1./36.,
+		1./54.,
+		1./54.,
 		// 3D
-		8./27.,
-		1./9.,
-		1./9.,
-		1./9.,
-		1./9.,
-		1./36.,
-		1./36.,
 		1./36.,
+		1./54.,
+		1./54.,
+		1./54.,
+		1./216.,
+		1./216.,
+		1./54.,
+		1./216.,
+		1./216.,
 		1./36.,
-		8./27.,
-		1./9.,
-		1./9.,
-		1./9.,
-		1./9.,
-		1./36.,
-		1./36.,
-		1./36.,
-		1./36.
+		1./54.,
+		1./54.,
+		1./54.,
+		1./216.,
+		1./216.,
+		1./54.,
+		1./216.,
+		1./216.
 	};
 
 	static constexpr std::array<uint64_t,Q> opposite_index = {
diff --git a/lib/core/tests/memory.cpp b/lib/core/tests/memory.cpp
index cdc6f8c..d59d212 100644
--- a/lib/core/tests/memory.cpp
+++ b/lib/core/tests/memory.cpp
@@ -46,13 +46,13 @@ SAW_TEST("Memory Estimate Scalar"){
 SAW_TEST("Memory Estimate Chunk"){
 	using namespace kel::lbm;
 	
-	SAW_EXPECT((memory_estimate<sch::TChunk>().get() == 480u), std::string{"TChunk isn't 480 bytes "} + std::to_string(memory_estimate<sch::TChunk>().get()) );
+	SAW_EXPECT((memory_estimate<sch::TChunk>().get() == 480u), std::string{"TChunk isn't 480 bytes, but is "} + std::to_string(memory_estimate<sch::TChunk>().get()) );
 }
 
 SAW_TEST("Memory Estimate Struct of Chunk"){
 	using namespace kel::lbm;
 	
-	SAW_EXPECT((memory_estimate<sch::TChunkStruct>().get() == 960u), std::string{"TChunk isn't 480 bytes "} + std::to_string(memory_estimate<sch::TChunk>().get()) );
+	SAW_EXPECT((memory_estimate<sch::TChunkStruct>().get() == 960u), std::string{"TChunkStruct isn't 960 bytes, but is "} + std::to_string(memory_estimate<sch::TChunk>().get()) );
 }
 
 }
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