From 5dade743e7c1e6b0b6001b4265bf792f0b05f93a Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Wed, 19 Aug 2026 16:36:14 +0200
Subject: Dangling

---
 examples/stdkr_2d_bgk/init.hpp | 124 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 examples/stdkr_2d_bgk/init.hpp

(limited to 'examples/stdkr_2d_bgk/init.hpp')

diff --git a/examples/stdkr_2d_bgk/init.hpp b/examples/stdkr_2d_bgk/init.hpp
new file mode 100644
index 0000000..abc2a26
--- /dev/null
+++ b/examples/stdkr_2d_bgk/init.hpp
@@ -0,0 +1,124 @@
+#pragma once
+
+#include "common.hpp"
+
+namespace kel {
+namespace lbm {
+
+template<typename T, typename Desc, typename Coll>
+saw::error_or<void> init(
+		const converter<T>& conv,
+		saw::data<sch::ChunkStruct<T,Desc>>& fields,
+		saw::data<sch::MacroStruct<T,Desc>>& macros
+){
+	(void) conv;
+
+	auto& info_f = fields.template get<"info">();
+	auto& porous_f = macros.template get<"porosity">();
+	// Set everything as walls
+	iterator<Desc::D>::apply(
+		[&](auto& index){
+			info_f.at(index).set(1u);
+		},
+		{},
+		info_f.get_dims(),
+		{}
+	);
+	// Fluid
+	iterator<Desc::D>::apply(
+		[&](auto& index){
+			info_f.at(index).set(2u);
+		},
+		{},
+		info_f.get_dims(),
+		{{1u,1u}}
+	);
+	
+	// Inflow
+	iterator<Desc::D>::apply(
+		[&](auto& index){
+			info_f.at(index).set(3u);
+		},
+		{{0u,0u}},
+		{{1u,dim_y}},
+		{{0u,1u}}
+	);
+	
+	// Outflow
+	iterator<Desc::D>::apply(
+		[&](auto& index){
+			info_f.at(index).set(4u);
+		},
+		{{dim_x-1u,0u}},
+		{{dim_x, dim_y}},
+		{{0u,1u}}
+	);
+	//
+	auto& df_f = fields.template get<"dfs_old">();
+	auto& rho_f = macros.template get<"density">();
+	auto& vel_f = macros.template get<"momentum">();
+	auto& por_f = macros.template get<"porosity">();
+	
+	iterator<Desc::D>::apply(
+		[&](auto& index){
+			auto& df = df_f.at(index);
+			auto& rho = rho_f.at(index);
+			por_f.at(index).at({}) = {1};
+			rho.at({}) = {1};
+			auto& vel = vel_f.at(index);
+			auto eq = equilibrium<T,Desc>(rho,vel);
+
+			df = eq;
+		},
+		{},// 0-index
+		df_f.get_dims()
+	);
+
+	iterator<Desc::D>::apply(
+		[&](auto& index){
+			auto& df = df_f.at(index);
+			auto& rho = rho_f.at(index);
+			rho.at({}) = {1};
+			auto& vel = vel_f.at(index);
+			if(info_f.at(index).get() == 2u){
+				vel.at({{0u}}) = 0.0;
+			}
+			auto eq = equilibrium<T,Desc>(rho,vel);
+
+			df = eq;
+		},
+		{},// 0-index
+		df_f.get_dims(),
+		{{1u,1u}}
+	);
+
+	{
+
+	}
+	{
+		saw::data<sch::Scalar<T>> radius_p;
+		radius_p.at({}).set(conv.meter_si_to_lbm({{0.05}}).handle().get());
+		std::cout<<"RADIUS: "<<radius_p.at({}).get()<<std::endl;
+		saw::data<sch::Scalar<T>> dense_p;
+		dense_p.at({}).set(1);
+		/*
+		auto& parts = particles.template get<"particles">();
+
+		{
+			auto& p = parts.at({0u});
+			auto& prb = p.template get<"rigid_body">();
+			auto& p_pos = prb.template get<"position">();
+			auto& p_posold = prb.template get<"position_old">();
+			p_pos.at({{0u}}) = conv.meter_si_to_lbm({{0.16}}).handle();
+			p_pos.at({{1u}}) = conv.meter_si_to_lbm({{0.2}}).handle();
+
+			p_posold = p_pos;
+		}
+		*/
+	}
+
+	return saw::make_void();
+}
+
+}
+}
-- 
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