From da25b3a1e7776a810d3bda5af3f363cf3e986cae Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Mon, 1 Jun 2026 20:36:51 +0200
Subject: Helping getting porosity checks against particles

---
 lib/core/c++/hlbm.hpp              | 33 ++++++++++++++++++++++-
 lib/core/c++/particle/porosity.hpp | 54 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 1 deletion(-)
 create mode 100644 lib/core/c++/particle/porosity.hpp

(limited to 'lib/core/c++')

diff --git a/lib/core/c++/hlbm.hpp b/lib/core/c++/hlbm.hpp
index 196de73..7590cc2 100644
--- a/lib/core/c++/hlbm.hpp
+++ b/lib/core/c++/hlbm.hpp
@@ -7,10 +7,39 @@
 namespace kel {
 namespace lbm {
 namespace cmpt {
+struct HlbmInit {}; 
 struct Hlbm {};
 struct HlbmParticle {};
 }
 
+template<typename T, typename Descriptor, typename Encode>
+class component<T, Descriptor, cmpt::HlbmInit, Encode> final {
+private:
+	typename saw::native_data_type<T>::type relaxation_;
+	saw::data<T> frequency_;
+public:
+	component(typename saw::native_data_type<T>::type relaxation__):
+		relaxation_{relaxation__},
+		frequency_{typename saw::native_data_type<T>::type(1) / relaxation_}
+	{}
+
+	template<typename CellFieldSchema, typename MacroFieldSchema>
+	void apply(const saw::data<CellFieldSchema, Encode>& field, const saw::data<MacroFieldSchema,Encode>& macros, saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> index, saw::data<sch::UInt64> time_step) const {
+		auto& porosity_f = macros.template get<"porosity">();
+		auto& particle_N_f = field.template get<"particle_N">();
+		auto& particle_D_f = field.template get<"particle_D">();
+
+		auto& por = porosity_f.at(index);
+		por = {};
+
+		auto& pnf = particle_N_f.at(index);
+		pnf = {};
+
+		auto& pnd = particle_D_f.at(index);
+		pnd = {};
+	}
+};
+
 /**
  * HLBM collision operator for LBM
  */
@@ -61,8 +90,9 @@ public:
 			dfs_old_f.at(index).at({i}) = dfs_old_f.at(index).at({i}) + frequency_ * (eq.at(i) - dfs_old_f.at(index).at({i}));
 		}
 
-		// porosity.at({}) = 1.0;
+		porosity.at({}) = 1.0;
 		D.at({}) = 0.0;
+		N = {};
 	}
 };
 
@@ -80,6 +110,7 @@ public:
 
 		/// Iterate over the grid bounds
 		// auto& grid = p.template get<"grid">();
+		
 
 	}
 };
diff --git a/lib/core/c++/particle/porosity.hpp b/lib/core/c++/particle/porosity.hpp
new file mode 100644
index 0000000..aa1ce5b
--- /dev/null
+++ b/lib/core/c++/particle/porosity.hpp
@@ -0,0 +1,54 @@
+#pragma once
+
+#include "particle.hpp"
+#include "../math/n_closest.hpp"
+
+namespace kel {
+namespace lbm {
+template<typename T, uint64_t D, typename Coll>
+class particle_porosity {
+public:
+	saw::data<sch::Scalar<T>> calculate(const saw::data<>& part_group, uint64_t p_i, const saw::data<sch::Vector<T,D>>& lbm_pos){
+		auto& mask = part_group.template get<"mask">();
+
+		auto& particles = part_group.template get<"particles">();
+		auto& part_i = particles.at({p_i});
+
+		auto& part_i_rb = part_i.template get<"rigid_body">();
+		auto& pirb = part_i_rb.template get<"position">();
+
+		auto& dist = lbm_pos = lbm_pos - pirb;
+
+		// index 0 is at 
+
+		return {};
+	}
+};
+
+
+template<typename T, uint64_t D, typename saw::native_data_type<T>::type radius>
+class particle_porosity<T, D, coll::ParticleCollisionSpheroid<T,radius>> final {
+public:
+	saw::data<sch::Scalar<T>> calculate(const saw::data<sch::Particle>&, uint64_t i, const saw::data<sch::Vector<T,D>>& lbm_pos){
+		saw::data<sch::Scalar<T>> por;
+		por.at({});
+
+		saw::data<sch::Scalar<T>> dps_2;
+		for(uint64_t i{0u}; i < D; ++i){
+			auto& dps_i = lbm_pos.at({{i}});
+			dps_2.at({}) = dps_i * dps_i;
+		}
+
+		saw::data<sch::Scalar<T>> rad_2;
+		rad_2.at({}).set(radius*radius);
+
+		saw::data<sch::Scalar<T>> inside;
+		if(dps_2.at({}).get() < rad_2.at({}).get()){
+			inside.at({}).set(1);
+		}
+		return inside;
+	}
+};
+
+}
+}
-- 
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