From eaa598784db491d37bdb1b9ff87d6e6bc9979476 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Tue, 18 Aug 2026 21:51:11 +0200
Subject: Feierabend

---
 .../step.hpp                                       | 56 ++++++++++++----------
 modules/core/c++/boundary.hpp                      | 37 +++++++-------
 2 files changed, 52 insertions(+), 41 deletions(-)

diff --git a/examples/schaefer_turek_durst_krause_rannbacher/step.hpp b/examples/schaefer_turek_durst_krause_rannbacher/step.hpp
index 1739edd..554a6ea 100644
--- a/examples/schaefer_turek_durst_krause_rannbacher/step.hpp
+++ b/examples/schaefer_turek_durst_krause_rannbacher/step.hpp
@@ -19,6 +19,8 @@ saw::error_or<void> step(
 	auto& q = dev.get_handle();
 	auto& info_f = fields.template get<"info">();
 	auto& porous_f = macros.template get<"porosity">();
+
+
 	
 	if constexpr ( std::is_same_v<Coll, method::Hlbm> ){
 		q.submit([&](acpp::sycl::handler& h){
@@ -48,16 +50,6 @@ saw::error_or<void> step(
 		q.submit([&](acpp::sycl::handler& h){
 			component<T,Desc,cmpt::Hlbm,encode::Sycl<saw::encode::Native>> collision{1.0};
 			component<T,Desc,cmpt::BounceBack,encode::Sycl<saw::encode::Native>> bb;
-
-			component<T,Desc,cmpt::ZouHeHorizontal<true>,encode::Sycl<saw::encode::Native>> flow_in{
-				[&](){
-					uint64_t target_t_i = 16u;
-					if(t_i.get() < target_t_i){
-						return 1.0 + (0.01 / target_t_i) * t_i.get();
-					}
-					return 1.001;
-				}()
-			};
 			component<T,Desc,cmpt::ZouHeHorizontal<false>,encode::Sycl<saw::encode::Native>> flow_out{1.0};
 
 			h.parallel_for(acpp::sycl::range<Desc::D>{dim_x,dim_y}, [=](acpp::sycl::id<Desc::D> idx){
@@ -78,7 +70,20 @@ saw::error_or<void> step(
 						collision.apply(fields,macros,index,t_i);
 						break;
 					case 3u:
-						flow_in.apply(fields,index,t_i);
+						{
+							component<T,Desc,cmpt::ZouHeVelocityX<true>,encode::Sycl<saw::encode::Native>> flow_in{
+								[&]() -> saw::data<sch::Vector<T,Desc::D>> {
+									saw::data<sch::Vector<T,Desc::D>> vel;
+									{
+										auto y_si = conv.meter_lbm_to_si(index.at({{1u}}).template cast_to<T>()).handle();
+										vel.at({{0u}}) = conv.velocity_si_to_lbm({{static_cast<typename saw::native_data_type<T>::type>((1.2 / 0.41) * y_si.get() - (1.2 / (0.41*0.41)) * y_si.get() * y_si.get())}}).handle();
+										vel.at({{1u}}) = 0.0f;
+									}
+									return vel;
+								}()
+							};
+							flow_in.apply(fields,index,t_i);
+						}
 						collision.apply(fields,macros,index,t_i);
 						break;
 					case 4u:
@@ -118,19 +123,9 @@ saw::error_or<void> step(
 
 		// auto coll_ev = 
 		q.submit([&](acpp::sycl::handler& h){
-			component<T,Desc,cmpt::BGK,encode::Sycl<saw::encode::Native>> bgk{0.8};
-			component<T,Desc,cmpt::FpLbm,encode::Sycl<saw::encode::Native>> collision{0.8};
+			component<T,Desc,cmpt::BGK,encode::Sycl<saw::encode::Native>> bgk{1.0};
+			component<T,Desc,cmpt::FpLbm,encode::Sycl<saw::encode::Native>> collision{1.0};
 			component<T,Desc,cmpt::BounceBack,encode::Sycl<saw::encode::Native>> bb;
-
-			component<T,Desc,cmpt::ZouHeHorizontal<true>,encode::Sycl<saw::encode::Native>> flow_in{
-				[&](){
-					uint64_t target_t_i = 8u;
-					if(t_i.get() < target_t_i){
-						return 1.0 + (0.01 / target_t_i) * t_i.get();
-					}
-					return 1.01;
-				}()
-			};
 			component<T,Desc,cmpt::ZouHeHorizontal<false>,encode::Sycl<saw::encode::Native>> flow_out{1.0};
 
 			h.parallel_for(acpp::sycl::range<Desc::D>{dim_x,dim_y}, [=](acpp::sycl::id<Desc::D> idx){
@@ -151,7 +146,20 @@ saw::error_or<void> step(
 						collision.apply(fields,macros,index,t_i);
 						break;
 					case 3u:
-						flow_in.apply(fields,index,t_i);
+						{
+							component<T,Desc,cmpt::ZouHeVelocityX<true>,encode::Sycl<saw::encode::Native>> flow_in{
+								[&]() -> saw::data<sch::Vector<T,Desc::D>> {
+									saw::data<sch::Vector<T,Desc::D>> vel;
+									{
+										auto y_si = conv.meter_lbm_to_si(index.at({{1u}}).template cast_to<T>()).handle();
+										vel.at({{0u}}) = conv.velocity_si_to_lbm({{static_cast<typename saw::native_data_type<T>::type>((1.2 / 0.41) * y_si.get() - (1.2 / (0.41*0.41)) * y_si.get() * y_si.get())}}).handle();
+										vel.at({{1u}}) = 0.0f;
+									}
+									return vel;
+								}()
+							};
+							flow_in.apply(fields,index,t_i);
+						}
 						bgk.apply(fields,macros,index,t_i);
 						break;
 					case 4u:
diff --git a/modules/core/c++/boundary.hpp b/modules/core/c++/boundary.hpp
index 8312584..ca2b228 100644
--- a/modules/core/c++/boundary.hpp
+++ b/modules/core/c++/boundary.hpp
@@ -12,7 +12,10 @@ template<uint64_t i>
 struct AntiBounceBack {};
 
 template<bool East>
-struct ZouHeVelocityX{};
+struct ZouHePressureX{};
+
+template<bool East>
+using ZouHeHorizontal = ZouHePressureX<East>;
 
 struct Equilibrium {};
 
@@ -170,7 +173,7 @@ public:
  *
  */
 template<typename FP, bool Dir, typename Encode>
-class component<FP, sch::Descriptor<2u,9u>, cmpt::ZouHeHorizontal<Dir>, Encode> final {
+class component<FP, sch::Descriptor<2u,9u>, cmpt::ZouHePressureX<Dir>, Encode> final {
 public:
 	using Descriptor = sch::Descriptor<2u,9u>;
 private:
@@ -224,7 +227,7 @@ public:
 };
 
 template<typename FP, bool East, typename Encode>
-class component<FP, sch::Descriptor<3u,27u>, cmpt::ZouHeHorizontal<East>, Encode> final {
+class component<FP, sch::Descriptor<3u,27u>, cmpt::ZouHePressureX<East>, Encode> final {
 public:
 	using Descriptor = sch::Descriptor<3u,27u>;
 private:
@@ -726,12 +729,12 @@ public:
 template<typename T, typename Descriptor, bool East, typename Encode>
 class component<T, Descriptor, cmpt::ZouHeVelocityX<East>, Encode> final {
 private:
-	saw::data<sch::Vector<T,Descriptor::D>> momentum_;
+	saw::data<sch::Vector<T,Descriptor::D>> velocity_;
 public:
 	component(
-		saw::data<sch::Vector<T,Descriptor::D>> momentum__
+		const saw::data<sch::Vector<T,Descriptor::D>>& velocity__
 	):
-		momentum_{momentum__}
+		velocity_{velocity__}
 	{}
 
 	template<typename CellFieldSchema>
@@ -753,20 +756,20 @@ public:
 		}
 
 		saw::data<sch::Scalar<T>> rho;
-		rho.at({}) = (dfs.at({0u}) + dfs.at({4u}) + dfs.at({3u}) + dir_sum * 2) / (momentum_.at({{0u}}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0)});
+		rho.at({}) = (dfs.at({0u}) + dfs.at({4u}) + dfs.at({3u}) + dir_sum * 2) / (velocity_.at({{0u}}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0)});
 
 		if constexpr (East) {
-			dfs.at({2u}) = dfs.at({1u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(2.0 / 3.0)} * rho.at({}) * momentum_.at({{0u}});
-			dfs.at({6u}) = dfs.at({5u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * momentum_.at({{0u}})
-				+ (dfs.at({3u}) - dfs.at({4u}) + rho.at({}) * momentum_.at({{1u}})) * 0.5f;
-			dfs.at({8u}) = dfs.at({7u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * momentum_.at({{0u}})
-				+ (dfs.at({4u}) - dfs.at({3u}) + rho.at({}) * momentum_.at({{1u}})) * 0.5f;
+			dfs.at({2u}) = dfs.at({1u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(2.0 / 3.0)} * rho.at({}) * velocity_.at({{0u}});
+			dfs.at({6u}) = dfs.at({5u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * velocity_.at({{0u}})
+				+ (dfs.at({3u}) - dfs.at({4u}) + rho.at({}) * velocity_.at({{1u}})) * 0.5f;
+			dfs.at({8u}) = dfs.at({7u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * velocity_.at({{0u}})
+				+ (dfs.at({4u}) - dfs.at({3u}) + rho.at({}) * velocity_.at({{1u}})) * 0.5f;
 		}else if constexpr ( not East ){
-			dfs.at({1u}) = dfs.at({2u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(2.0 / 3.0)} * rho.at({}) * momentum_.at({{0u}});
-			dfs.at({5u}) = dfs.at({6u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * momentum_.at({{0u}})
-				+ (dfs.at({4u}) - dfs.at({3u}) + rho.at({}) * momentum_.at({{1u}}))*0.5f;
-			dfs.at({7u}) = dfs.at({8u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * momentum_.at({{0u}})
-				+ (dfs.at({3u}) - dfs.at({4u}) + rho.at({}) * momentum_.at({{1u}}))*0.5f;
+			dfs.at({1u}) = dfs.at({2u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(2.0 / 3.0)} * rho.at({}) * velocity_.at({{0u}});
+			dfs.at({5u}) = dfs.at({6u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * velocity_.at({{0u}})
+				+ (dfs.at({4u}) - dfs.at({3u}) + rho.at({}) * velocity_.at({{1u}}))*0.5f;
+			dfs.at({7u}) = dfs.at({8u}) + saw::data<T>{static_cast<saw::native_data_type<T>::type>(1.0 / 6.0)} * rho.at({}) * velocity_.at({{0u}})
+				+ (dfs.at({3u}) - dfs.at({4u}) + rho.at({}) * velocity_.at({{1u}}))*0.5f;
 		}
 	}
 };
-- 
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