From 80deace4d4b2c93945feeec42a8269f3ba2443d2 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Tue, 4 Aug 2026 19:52:08 +0200
Subject: Asking myself how I had a stable implementation before

---
 .../sim.cpp                                        |  11 +-
 modules/core/c++/fplbm.hpp                         | 126 ++++++++++++++++++---
 modules/core/c++/psm.hpp                           |  61 +++++++++-
 3 files changed, 176 insertions(+), 22 deletions(-)

diff --git a/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp b/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp
index f6c09e9..09b2616 100644
--- a/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp
+++ b/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp
@@ -141,7 +141,7 @@ saw::error_or<void> init(
 	rad.at({}) = dim_y * 0.1f;
 	saw::data<sch::Scalar<T>> dense;
 	dense.at({}) = 1.0f;
-	particles = create_spheroid_particle_group<T,Desc::D,particle_amount>(rad,dense,{16u});
+	particles = create_spheroid_particle_group<T,Desc::D,particle_amount>(rad,dense,{1u});
 	{
 		auto& rb = particles.template get<"particles">().at({0u}).template get<"rigid_body">();
 		auto& rbp = rb.template get<"position">();
@@ -179,7 +179,7 @@ saw::error_or<void> step(
 			for(uint64_t i = 0u; i < Desc::D; ++i){
 				index.at({{i}}).set(idx[i]);
 			}
-
+			
 			fplbm_reset.apply(fields,macros,index,t_i);
 		});
 	}).wait();
@@ -193,12 +193,13 @@ saw::error_or<void> step(
 				index.at({{i}}).set(idx[i]);
 			}
 
-			fplbm_one_part.apply(fields,macros,particles,index,t_i,{1u});
+			fplbm_one_part.apply(fields,macros,particles,index,t_i,{16u});
 		});
 	}).wait();
 
 	// 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::BounceBack,encode::Sycl<saw::encode::Native>> bb;
 
@@ -232,11 +233,11 @@ saw::error_or<void> step(
 					break;
 				case 3u:
 					flow_in.apply(fields,index,t_i);
-					collision.apply(fields,macros,index,t_i);
+					bgk.apply(fields,macros,index,t_i);
 					break;
 				case 4u:
 					flow_out.apply(fields,index,t_i);
-					collision.apply(fields,macros,index,t_i);
+					bgk.apply(fields,macros,index,t_i);
 				break;
 				default:
 				break;
diff --git a/modules/core/c++/fplbm.hpp b/modules/core/c++/fplbm.hpp
index cfb0062..4acdd36 100644
--- a/modules/core/c++/fplbm.hpp
+++ b/modules/core/c++/fplbm.hpp
@@ -10,6 +10,7 @@ namespace cmpt {
 struct FpLbmReset{};
 struct FpLbm {};
 struct FpLbmOneParticle {};
+struct FpLbmOneParticleImplicit {};
 struct FpLbmOneParticleNoVelocity{};
 }
 namespace method {
@@ -36,18 +37,20 @@ public:
 		for(uint64_t i{0u}; i < Descriptor::D; ++i){
 			force.at({{i}}) = 0.0;
 		}
+		auto info = field.template get<"info">().at(index).get();
+		if(info == 2u){
+			bool is_even = ((time_step.get() % 2) == 0);
 
-		bool is_even = ((time_step.get() % 2) == 0);
-
-		auto& dfs_old_f = (is_even) ? field.template get<"dfs_old">() : field.template get<"dfs">();
-		auto& dfs = dfs_old_f.at(index);
+			auto& dfs_old_f = (is_even) ? field.template get<"dfs_old">() : field.template get<"dfs">();
+			auto& dfs = dfs_old_f.at(index);
 
-		auto& rho_f = macros.template get<"density">();
-		auto& rho = rho_f.at(index);
-		auto& vel_f = macros.template get<"velocity">();
-		auto& vel = vel_f.at(index);
+			auto& rho_f = macros.template get<"density">();
+			auto& rho = rho_f.at(index);
+			auto& vel_f = macros.template get<"velocity">();
+			auto& vel = vel_f.at(index);
 
-		compute_rho_u<T,Descriptor>(dfs,rho,vel);
+			compute_rho_u<T,Descriptor>(dfs,rho,vel);
+		}
 	}
 };
 
@@ -83,7 +86,7 @@ public:
 		auto& vel_f = macros.template get<"velocity">();
 		saw::data<sch::Vector<T,Descriptor::D>>& vel = vel_f.at(index);
 
-		compute_rho_u<T,Descriptor>(dfs,rho,vel);
+		// compute_rho_u<T,Descriptor>(dfs,rho,vel);
 		auto eq = equilibrium<T,Descriptor>(rho,vel);
 
 		using dfi = df_info<T,Descriptor>;
@@ -158,10 +161,94 @@ public:
 		auto& pirb_pos = pirb.template get<"position">();
 		auto& pirb_pos_old = pirb.template get<"position_old">();
 		
+
+		auto& p_coll = pg.template get<"collision">().at({});
+		auto& p_rad = p_coll.template get<"radius">();
+
+		auto eo_aabb = particle_aabb<typename ParticleSchema::ValueType>::calculate(pg,{{0u}},vel_f.meta());
+		if(eo_aabb.is_error()){
+			return;
+		}
+		auto& aabb = eo_aabb.get_value();
+
+		saw::data<sch::Scalar<T>> two;
+		two.at({}).set(2.0f);
+
+		saw::data<sch::Scalar<T>> one;
+		one.at({}) = 1.0;
+		
+		saw::data<sch::Scalar<T>> eps;
+		eps.at({}) = 1.5f;
+		
 		saw::data<sch::Scalar<T>> sss;
-		sss.at({}) = sub_steps.template cast_to<T>();
+		sss.at({}) = one.at({}) / sub_steps.template cast_to<T>();
 		auto vel_s = (pirb_pos-pirb_pos_old) / sss;
 
+		saw::data<sch::Vector<T,Descriptor::D>> force_p{};
+
+		iterator<Descriptor::D>::apply([&](const auto& index_f) -> void {
+			auto& force = force_f.at(index_f);
+			auto& vel = vel_f.at(index_f);
+			auto& por = por_f.at(index_f);
+			auto& rho = rho_f.at(index_f);
+
+			saw::data<sch::Vector<T,Descriptor::D>> rel_dist = saw::math::vectorize_data(index_f).template cast_to<T>() - pirb_pos;
+
+			por = particle_porosity<T,Descriptor::D,1u,por::ParticleSpheroid<T>>::calculate(rel_dist,p_rad,eps);
+			auto flip_por = one - por;
+
+			// vel_s is technically time the density of the particle?
+
+			force = ( vel_s * rho - vel * rho ) * two * flip_por;
+
+			force_p = force_p - force;
+		}, aabb.template get<"a">(), aabb.template get<"b">());
+
+		auto& pirb_acc = pirb.template get<"acceleration">();
+		pirb_acc = force_p / pg.template get<"total_mass">().at({});
+
+		for(saw::data<sch::UInt64> i{0u}; i < sub_steps; ++i){
+			//verlet_step_lambda<T,Descriptor::D>(pi,sss);
+		}
+	}
+};
+
+template<typename T, typename Descriptor, typename Encode>
+class component<T, Descriptor, cmpt::FpLbmOneParticleImplicit, Encode> final {
+public:
+	using Component = cmpt::FpLbmOneParticle;
+private:
+public:
+	component() = default;
+
+	template<typename CellFieldSchema, typename MacroFieldSchema, typename ParticleSchema>
+	void apply(const saw::data<CellFieldSchema, Encode>& field, const saw::data<MacroFieldSchema,Encode>& macros, const saw::data<ParticleSchema,Encode>& pg, saw::data<sch::FixedArray<sch::UInt64,1u>> index, saw::data<sch::UInt64> time_step, saw::data<sch::UInt64> sub_steps) const {
+	// void apply(saw::data<CellFieldSchema, Encode>& field, saw::data<sch::FixedArray<sch::UInt64, Descriptor::D>> index, saw::data<sch::UInt64> time_step){
+		bool is_even = ((time_step.get() % 2) == 0);
+
+		//auto& dfs_old_f = (is_even) ? field.template get<"dfs_old">() : field.template get<"dfs">();
+		// auto& dfs = dfs_old_f.at(index);
+
+		auto& rho_f = macros.template get<"density">();
+		auto& vel_f = macros.template get<"velocity">();
+		auto& por_f = macros.template get<"porosity">();
+		auto& force_f = macros.template get<"force">();
+
+		/**
+		 * The other methods all work with a flipped porosity.
+		 * For compat reasons this is also flipped
+		 */
+		// TODO - Change to tuple later
+		auto parts = pg.template get<"particles">();
+
+		auto parts_size = parts.meta().at({0u});
+		auto& pi = parts.at(index);		
+
+		auto& pirb = pi.template get<"rigid_body">();
+		auto& pirb_pos = pirb.template get<"position">();
+		auto& pirb_pos_old = pirb.template get<"position_old">();
+		
+
 		auto& p_coll = pg.template get<"collision">().at({});
 		auto& p_rad = p_coll.template get<"radius">();
 
@@ -172,15 +259,19 @@ public:
 		auto& aabb = eo_aabb.get_value();
 
 		saw::data<sch::Scalar<T>> two;
-		two.at({}).set(2);
+		two.at({}).set(2.0f);
 
 		saw::data<sch::Scalar<T>> one;
 		one.at({}) = 1.0;
 		
 		saw::data<sch::Scalar<T>> eps;
 		eps.at({}) = 1.5f;
+		
+		saw::data<sch::Scalar<T>> sss;
+		sss.at({}) = one.at({}) / sub_steps.template cast_to<T>();
+		auto vel_s = (pirb_pos-pirb_pos_old) / sss;
 
-		saw::data<sch::Vector<T,Descriptor::D>> force_p;
+		saw::data<sch::Vector<T,Descriptor::D>> force_p{};
 
 		iterator<Descriptor::D>::apply([&](const auto& index_f) -> void {
 			auto& force = force_f.at(index_f);
@@ -193,13 +284,16 @@ public:
 			por = particle_porosity<T,Descriptor::D,1u,por::ParticleSpheroid<T>>::calculate(rel_dist,p_rad,eps);
 			auto flip_por = one - por;
 
-			force = ( vel_s * rho -  vel * rho ) * two * flip_por;
+			// vel_s is technically time the density of the particle?
+
+			force = ( vel_s * rho - vel * rho ) * flip_por / (one + flip_por / two);
+			// force = ( vel_s * rho - vel * rho ) * two * flip_por;
 
-			force_p = force_p + force;
+			force_p = force_p - force;
 		}, aabb.template get<"a">(), aabb.template get<"b">());
 
 		auto& pirb_acc = pirb.template get<"acceleration">();
-		pirb_acc = - force_p / pg.template get<"total_mass">().at({});
+		pirb_acc = force_p / pg.template get<"total_mass">().at({});
 
 		for(saw::data<sch::UInt64> i{0u}; i < sub_steps; ++i){
 			verlet_step_lambda<T,Descriptor::D>(pi,sss);
diff --git a/modules/core/c++/psm.hpp b/modules/core/c++/psm.hpp
index 02db1e1..c53dbf9 100644
--- a/modules/core/c++/psm.hpp
+++ b/modules/core/c++/psm.hpp
@@ -86,8 +86,18 @@ public:
 template<typename T, typename Descriptor, typename Encode>
 class component<T, Descriptor, cmpt::PsmOneParticle, Encode> final {
 private:
+	saw::data<T> relaxation_;
+	saw::data<T> frequency_;
 public:
-	component() = default;
+	component(
+		typename saw::native_data_type<T>::type relaxation__
+	):
+		relaxation_{relaxation__}
+	{
+		saw::data<T> one;
+		one = 1.0;
+		frequency_ = one / relaxation_;
+	}
 
 	template<typename CellFieldSchema, typename MacroFieldSchema, typename ParticleSchema>
 	void apply(const saw::data<CellFieldSchema, Encode>& field, const saw::data<MacroFieldSchema,Encode>& macros, const saw::data<ParticleSchema,Encode>& particles, saw::data<sch::FixedArray<sch::UInt64,1u>> index, saw::data<sch::UInt64> time_step) const {
@@ -101,6 +111,55 @@ public:
 		auto& rho_f = macros.template get<"density">();
 		auto& vel_f = macros.template get<"velocity">();
 		
+		saw::data<sch::Scalar<T>>& rho = rho_f.at(index);
+		saw::data<sch::Vector<T,Descriptor::D>>& vel = vel_f.at(index);
+
+		compute_rho_u<T,Descriptor>(dfs_old_f.at(index),rho,vel);
+		
+		auto eq = equilibrium<T,Descriptor>(rho,vel);
+
+		saw::data<T> one{1.0};
+		auto& porous = porous_f.at(index);
+		auto flip_porous = one - porous.at({});
+
+		auto& dfs = dfs_old_f.at(index);
+
+		auto dfs_cpy = dfs;
+
+		for(uint64_t i = 0u; i < Descriptor::Q; ++i){
+			uint64_t i_opp = dfi::opposite_index[i];
+			dfs.at({i}) = dfs_cpy.at({i}) + frequency_ * (eq.at(i) - dfs_cpy.at({i})) * porous.at({}) + (dfs_cpy.at({i_opp}) - dfs_cpy.at({i}) ) * flip_porous;
+		}
+
+		auto& force_f = macros.template get<"force">();
+		auto& force = force_f.at(index);
+		for(uint64_t k{0u}; k < Descriptor::D; ++k){
+			force.at({{k}}).set(0);
+		}
+
+		/////////
+		saw::data<sch::Vector<T,Descriptor::D>> momentum;
+		for(uint64_t i = 0u; i < Descriptor::Q; ++i){
+			
+			saw::data<sch::Vector<T,Descriptor::D>> e_i;
+			saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> n_ind_i;
+			for(uint64_t k{0u}; k < Descriptor::D; ++k){
+				e_i.at({{k}}) = dfi::directions[i][k];
+				n_ind_i.at({k}) = (dfi::directions[i])[k];
+			}
+
+			uint64_t i_opp = dfi::opposite_index[i];
+
+			saw::data<T> dfs_added = dfs.at({i}) - dfs_old_f.at(n_ind_i).at({i_opp});
+			saw::data<sch::Scalar<T>> dfs_added_v;
+			dfs_added_v.at({}) = dfs_added;
+			auto ei_dfs = e_i * dfs_added_v;
+
+			momentum = momentum + ei_dfs;
+		}
+		
+		// Set Force
+		force = momentum * porous_f.at(index);
 	}
 };
 
-- 
cgit v1.2.3


From a0767a86817055744230239284441fdbb024fab5 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Wed, 5 Aug 2026 17:13:19 +0200
Subject: WOrking on psm 2way

---
 default.nix                                        |   5 +
 .../sim.cpp                                        |   4 +-
 .../.nix/derivation.nix                            |  41 ++
 .../SConscript                                     |  34 ++
 .../SConstruct                                     |  81 ++++
 .../moving_poiseulle_particles_2d_psm_gpu/sim.cpp  | 458 +++++++++++++++++++++
 modules/core/c++/fplbm.hpp                         |   5 +-
 modules/core/c++/psm.hpp                           | 172 +++++---
 8 files changed, 736 insertions(+), 64 deletions(-)
 create mode 100644 examples/moving_poiseulle_particles_2d_psm_gpu/.nix/derivation.nix
 create mode 100644 examples/moving_poiseulle_particles_2d_psm_gpu/SConscript
 create mode 100644 examples/moving_poiseulle_particles_2d_psm_gpu/SConstruct
 create mode 100644 examples/moving_poiseulle_particles_2d_psm_gpu/sim.cpp

diff --git a/default.nix b/default.nix
index 241d84a..f560d7e 100644
--- a/default.nix
+++ b/default.nix
@@ -132,6 +132,11 @@ in rec {
 			inherit kel;
 		};
 		
+		moving_poiseulle_particles_2d_psm_gpu = pkgs.callPackage ./examples/moving_poiseulle_particles_2d_psm_gpu/.nix/derivation.nix {
+			inherit pname version stdenv forstio adaptive-cpp;
+			inherit kel;
+		};
+		
 		poiseulle_particles_2d_psm_gpu = pkgs.callPackage ./examples/poiseulle_particles_2d_psm_gpu/.nix/derivation.nix {
 			inherit pname version stdenv forstio adaptive-cpp;
 			inherit kel;
diff --git a/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp b/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp
index 09b2616..c82f632 100644
--- a/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp
+++ b/examples/moving_poiseulle_particles_2d_fplbm_gpu/sim.cpp
@@ -185,7 +185,7 @@ saw::error_or<void> step(
 	}).wait();
 
 	q.submit([&](acpp::sycl::handler& h){
-		component<T,Desc,cmpt::FpLbmOneParticle,encode::Sycl<saw::encode::Native>> fplbm_one_part;
+		component<T,Desc,cmpt::FpLbmOneParticleImplicit,encode::Sycl<saw::encode::Native>> fplbm_one_part;
 
 		h.parallel_for(acpp::sycl::range<1u>{particle_amount}, [=](acpp::sycl::id<1u> idx){
 			saw::data<sch::FixedArray<sch::UInt64,1u>> index;
@@ -262,7 +262,7 @@ saw::error_or<void> lbm_main(int argc, char** argv){
 	}
 	auto& lbm_dir = eo_lbm_dir.get_value();
 
-	auto out_dir = lbm_dir / "moving_poiseulle_particles_2d_fplbm_gpu";
+	auto out_dir = lbm_dir / "moving_poiseulle_particles_2d_fplbm_imp_gpu";
 
 	{
 		std::error_code ec;
diff --git a/examples/moving_poiseulle_particles_2d_psm_gpu/.nix/derivation.nix b/examples/moving_poiseulle_particles_2d_psm_gpu/.nix/derivation.nix
new file mode 100644
index 0000000..01e1f12
--- /dev/null
+++ b/examples/moving_poiseulle_particles_2d_psm_gpu/.nix/derivation.nix
@@ -0,0 +1,41 @@
+{ lib
+, stdenv
+, scons
+, clang-tools
+, forstio
+, python3
+, pname
+, version
+, adaptive-cpp
+, kel
+}:
+
+stdenv.mkDerivation {
+	pname = pname + "-examples-" + "moving_poiseulle_particles_2d_psm_gpu";
+	inherit version;
+	src = ./..;
+
+	nativeBuildInputs = [
+		scons
+		clang-tools
+		python3
+	];
+
+	buildInputs = [
+		forstio.core
+		forstio.async
+		forstio.codec
+		forstio.codec-unit
+		forstio.io
+    forstio.remote
+    forstio.remote-filesystem
+		forstio.codec-json
+		adaptive-cpp
+		kel.lbm.core
+		kel.lbm.sycl
+	];
+
+	preferLocalBuild = true;
+
+	outputs = [ "out" "dev" ];
+}
diff --git a/examples/moving_poiseulle_particles_2d_psm_gpu/SConscript b/examples/moving_poiseulle_particles_2d_psm_gpu/SConscript
new file mode 100644
index 0000000..e8102aa
--- /dev/null
+++ b/examples/moving_poiseulle_particles_2d_psm_gpu/SConscript
@@ -0,0 +1,34 @@
+#!/bin/false
+
+import os
+import os.path
+import glob
+
+
+Import('env')
+
+dir_path = Dir('.').abspath
+
+# Environment for base library
+examples_env = env.Clone();
+examples_env['CXX'] = 'syclcc-clang';
+examples_env['CXXFLAGS'] += ['-O3'];
+
+examples_env.sources = sorted(glob.glob(dir_path + "/*.cpp"))
+examples_env.headers = sorted(glob.glob(dir_path + "/*.hpp"))
+
+env.sources += examples_env.sources;
+env.headers += examples_env.headers;
+
+# Cavity2D
+examples_objects = [];
+examples_env.add_source_files(examples_objects, ['sim.cpp'], shared=False);
+examples_env.poiseulle_2d_gpu = examples_env.Program('#bin/moving_poiseulle_particles_2d_psm_gpu', [examples_objects]);
+
+# Set Alias
+env.examples = [
+	examples_env.poiseulle_2d_gpu
+];
+env.Alias('examples', env.examples);
+env.targets += ['examples'];
+env.Install('$prefix/bin/', env.examples);
diff --git a/examples/moving_poiseulle_particles_2d_psm_gpu/SConstruct b/examples/moving_poiseulle_particles_2d_psm_gpu/SConstruct
new file mode 100644
index 0000000..0611b67
--- /dev/null
+++ b/examples/moving_poiseulle_particles_2d_psm_gpu/SConstruct
@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import os.path
+import glob
+import re
+
+
+if sys.version_info < (3,):
+    def isbasestring(s):
+        return isinstance(s,basestring)
+else:
+    def isbasestring(s):
+        return isinstance(s, (str,bytes))
+
+def add_kel_source_files(self, sources, filetype, lib_env=None, shared=False, target_post=""):
+
+    if isbasestring(filetype):
+        dir_path = self.Dir('.').abspath
+        filetype = sorted(glob.glob(dir_path+"/"+filetype))
+
+    for path in filetype:
+        target_name = re.sub( r'(.*?)(\.cpp|\.c\+\+)', r'\1' + target_post, path )
+        if shared:
+            target_name+='.os'
+            sources.append( self.SharedObject( target=target_name, source=path ) )
+        else:
+            target_name+='.o'
+            sources.append( self.StaticObject( target=target_name, source=path ) )
+    pass
+
+def isAbsolutePath(key, dirname, env):
+	assert os.path.isabs(dirname), "%r must have absolute path syntax" % (key,)
+
+env_vars = Variables(
+	args=ARGUMENTS
+)
+
+env_vars.Add('prefix',
+	help='Installation target location of build results and headers',
+	default='/usr/local/',
+	validator=isAbsolutePath
+)
+
+env_vars.Add('build_examples',
+	help='If examples should be built',
+	default="true"
+)
+
+env=Environment(ENV=os.environ, variables=env_vars, CPPPATH=[],
+    CPPDEFINES=['SAW_UNIX'],
+    CXXFLAGS=[
+        '-std=c++20',
+        '-g',
+        '-Wall',
+        '-Wextra'
+    ],
+    LIBS=[
+        'forstio-core',
+        'forstio-async',
+        'forstio-io'
+    ]
+);
+env.__class__.add_source_files = add_kel_source_files
+env.Tool('compilation_db');
+env.cdb = env.CompilationDatabase('compile_commands.json');
+
+env.objects = [];
+env.sources = [];
+env.headers = [];
+env.targets = [];
+
+Export('env')
+SConscript('SConscript')
+
+env.Alias('cdb', env.cdb);
+env.Alias('all', [env.targets]);
+env.Default('all');
+
+env.Alias('install', '$prefix')
diff --git a/examples/moving_poiseulle_particles_2d_psm_gpu/sim.cpp b/examples/moving_poiseulle_particles_2d_psm_gpu/sim.cpp
new file mode 100644
index 0000000..2c4c9d1
--- /dev/null
+++ b/examples/moving_poiseulle_particles_2d_psm_gpu/sim.cpp
@@ -0,0 +1,458 @@
+#include <kel/lbm/sycl/lbm.hpp>
+#include <kel/lbm/lbm.hpp>
+#include <kel/lbm/particle.hpp>
+
+#include <forstio/io/io.hpp>
+#include <forstio/remote/filesystem/easy.hpp>
+#include <forstio/codec/json/json.hpp>
+#include <forstio/codec/simple.hpp>
+
+namespace kel {
+namespace lbm {
+
+constexpr uint64_t dim_y = 256ul;
+constexpr uint64_t dim_x = dim_y * 20ul;
+
+constexpr uint64_t particle_amount = 1ul;
+
+namespace sch {
+using namespace saw::schema;
+
+using InfoChunk = Chunk<UInt8, 0u, dim_x, dim_y>;
+
+template<typename T, typename Desc>
+using DfChunk = Chunk<FixedArray<T,Desc::Q>, 1u, dim_x, dim_y>;
+
+template<typename T, typename Desc>
+using ScalarChunk = Chunk<Scalar<T>, 0u, dim_x, dim_y>;
+
+template<typename T, typename Desc>
+using VectorChunk = Chunk<Vector<T,Desc::D>, 0u, dim_x, dim_y>;
+
+template<typename T, typename Desc>
+using ChunkStruct = Struct<
+	Member<InfoChunk, "info">,
+	Member<DfChunk<T,Desc>, "dfs">,
+	Member<DfChunk<T,Desc>, "dfs_old">,
+	Member<VectorChunk<T,Desc>, "particle_N">,
+	Member<ScalarChunk<T,Desc>, "particle_D">
+>;
+
+template<typename T, typename Desc>
+using VelChunk = Chunk<Vector<T,Desc::D>, 0u, dim_x, dim_y>;
+
+template<typename T>
+using RhoChunk = Chunk<Scalar<T>, 0u, dim_x, dim_y>;
+
+template<typename T, typename Desc>
+using MacroStruct = Struct<
+	Member<VelChunk<T,Desc>, "velocity">,
+	Member<RhoChunk<T>, "density">,
+	Member<ScalarChunk<T,Desc>, "porosity">,
+	Member<VelChunk<T,Desc>, "force">
+>;
+
+//template<typename T, typename Desc>
+//using ParticleArray = Array<
+//	Particle<T,Desc::D>
+//>;
+
+template<typename T, typename Desc>
+using ParticleSpheroidGroup = ParticleGroup<T,Desc::D,1u,coll::Spheroid<T>>;
+}
+
+template<typename T, typename Desc>
+saw::error_or<void> init(
+	saw::data<sch::ChunkStruct<T,Desc>>& fields,
+	saw::data<sch::MacroStruct<T,Desc>>& macros,
+	saw::data<sch::ParticleSpheroidGroup<T,Desc>>& particles
+){
+	auto& info_f = fields.template get<"info">();
+	// 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& dfs_old_f = fields.template get<"dfs_old">();
+	auto& dfs_f = fields.template get<"dfs">();
+	auto& rho_f = macros.template get<"density">();
+	auto& vel_f = macros.template get<"velocity">();
+	auto& por_f = macros.template get<"porosity">();
+	auto& force_f = macros.template get<"force">();
+	
+	iterator<Desc::D>::apply(
+		[&](auto& index){
+			auto& dfs = dfs_f.at(index);
+			auto& rho = rho_f.at(index);
+			por_f.at(index).at({}) = {1};
+			rho.at({}) = {1};
+			auto& vel = vel_f.at(index);
+			for(uint64_t i{0u}; i < Desc::D; ++i){
+				vel.at({{i}}).set(0);
+			}
+			auto eq = equilibrium<T,Desc>(rho,vel);
+
+			dfs = eq;
+			dfs_old_f.at(index) = dfs;
+			auto& force = force_f.at(index);
+			for(uint64_t i{0u}; i < Desc::D; ++i){
+				force.at({{i}}).set(0);
+			}
+		},
+		{},// 0-index
+		dfs_f.get_dims()
+	);
+
+	saw::data<sch::Scalar<T>> rad;
+	rad.at({}) = dim_y * 0.1f;
+	saw::data<sch::Scalar<T>> dense;
+	dense.at({}) = 1.0f;
+	particles = create_spheroid_particle_group<T,Desc::D,particle_amount>(rad,dense,{1u});
+	{
+		auto& rb = particles.template get<"particles">().at({0u}).template get<"rigid_body">();
+		auto& rbp = rb.template get<"position">();
+		rbp.at({{0u}}) = 0.25 * dim_x;
+		rbp.at({{1u}}) = 0.5 * dim_y;
+		rb.template get<"position_old">() = rbp;
+		saw::data<sch::Vector<T,Desc::D>> zero;
+		zero.at({{0u}}) = 0.0f;
+		zero.at({{1u}}) = 0.0f;
+		rb.template get<"acceleration">() = zero;
+		rb.template get<"rotation">() = {};
+		rb.template get<"rotation_old">() = {};
+		rb.template get<"angular_acceleration">() = {};
+	}
+
+	return saw::make_void();
+}
+
+template<typename T, typename Desc>
+saw::error_or<void> step(
+		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::Ptr<sch::ParticleSpheroidGroup<T,Desc>>,encode::Sycl<saw::encode::Native>>& particles,
+		saw::data<sch::UInt64> t_i,
+		device& dev
+){
+	auto& q = dev.get_handle();
+	auto& info_f = fields.template get<"info">();
+	auto& porous_f = macros.template get<"porosity">();
+
+	q.submit([&](acpp::sycl::handler& h){
+		component<T,Desc,cmpt::PsmReset,encode::Sycl<saw::encode::Native>> psm_reset;
+		h.parallel_for(acpp::sycl::range<Desc::D>{dim_x,dim_y}, [=](acpp::sycl::id<Desc::D> idx){
+			saw::data<sch::FixedArray<sch::UInt64,Desc::D>> index;
+			for(uint64_t i = 0u; i < Desc::D; ++i){
+				index.at({{i}}).set(idx[i]);
+			}
+			
+			psm_reset.apply(fields,macros,index,t_i);
+		});
+	}).wait();
+
+	q.submit([&](acpp::sycl::handler& h){
+		component<T,Desc,cmpt::PsmOneParticle,encode::Sycl<saw::encode::Native>> psm_one_part;
+
+		h.parallel_for(acpp::sycl::range<1u>{particle_amount}, [=](acpp::sycl::id<1u> idx){
+			saw::data<sch::FixedArray<sch::UInt64,1u>> index;
+			for(uint64_t i = 0u; i < 1u; ++i){
+				index.at({{i}}).set(idx[i]);
+			}
+
+			psm_one_part.apply(fields,macros,particles,index,t_i,{16u});
+		});
+	}).wait();
+
+	// 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::Psm,encode::Sycl<saw::encode::Native>> collision{0.8};
+		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){
+			saw::data<sch::FixedArray<sch::UInt64,Desc::D>> index;
+			for(uint64_t i = 0u; i < Desc::D; ++i){
+				index.at({{i}}).set(idx[i]);
+			}
+
+			auto info = info_f.at(index);
+			
+			switch(info.get()){
+				case 0u:
+				break;
+				case 1u:
+					bb.apply(fields,index,t_i);
+				break;
+				case 2u:
+					collision.apply(fields,macros,index,t_i);
+					break;
+				case 3u:
+					flow_in.apply(fields,index,t_i);
+					bgk.apply(fields,macros,index,t_i);
+					break;
+				case 4u:
+					flow_out.apply(fields,index,t_i);
+					bgk.apply(fields,macros,index,t_i);
+				break;
+				default:
+				break;
+			}
+		});
+	}).wait();
+
+	return saw::make_void();
+}
+}
+}
+
+template<typename T, typename Desc>
+saw::error_or<void> lbm_main(int argc, char** argv){
+	using namespace kel::lbm;
+
+	using dfi = df_info<T,Desc>;
+
+	auto eo_lbm_dir = output_directory();
+	if(eo_lbm_dir.is_error()){
+		return std::move(eo_lbm_dir.get_error());
+	}
+	auto& lbm_dir = eo_lbm_dir.get_value();
+
+	auto out_dir = lbm_dir / "moving_poiseulle_particles_2d_psm_gpu";
+
+	{
+		std::error_code ec;
+		std::filesystem::create_directories(out_dir,ec);
+		if(ec != std::errc{}){
+			return saw::make_error<saw::err::critical>("Could not create output directory");
+		}
+	}
+
+	converter<T> conv {
+		// delta_x
+		{{1.0}},
+		// delta_t
+		{{1.0}}
+	};
+	
+	print_lbm_meta<T,Desc>(conv,{0.1},{1e-4},{0.4 * dim_y});
+
+	// saw::data<sch::FixedArray<sch::UInt64,Desc::D>> meta{{dim_x,dim_y}};
+	auto lbm_data_ptr = saw::heap<saw::data<sch::ChunkStruct<T,Desc>>>();
+	auto lbm_macro_data_ptr = saw::heap<saw::data<sch::MacroStruct<T,Desc>>>();
+	auto lbm_parts_data_ptr = saw::heap<saw::data<sch::ParticleSpheroidGroup<T,Desc>>>();
+	//saw::data<sch::Ptr<sch::ParticleSpheroidGroup<T,Desc>>,encode::Sycl<saw::encode::Native>>& particles
+	
+	std::cout<<"Estimated Bytes: "<<memory_estimate<sch::ChunkStruct<T,Desc>,sch::MacroStruct<T,Desc>>().get()<<std::endl;
+
+	auto eo_aio = saw::setup_async_io();
+	if(eo_aio.is_error()){
+		return std::move(eo_aio.get_error());
+	}
+	auto& aio = eo_aio.get_value();
+	saw::wait_scope wait{aio.event_loop};
+
+	bool krun = true;
+	bool print_status = false;
+	aio.event_port.on_signal(saw::Signal::Terminate).then([&](){
+		krun = false;
+	}).detach();
+	aio.event_port.on_signal(saw::Signal::User1).then([&](){
+		print_status = true;
+	}).detach();
+
+	device dev;
+
+	auto& sycl_q = dev.get_handle();
+
+	sycl_q.wait();
+	{
+		auto eov = init<T,Desc>(*lbm_data_ptr,*lbm_macro_data_ptr,*lbm_parts_data_ptr);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+	{
+		auto eov = write_vtk_file(out_dir,"initial_state",0u,*lbm_data_ptr);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+
+	saw::data<sch::ChunkStruct<T,Desc>, encode::Sycl<saw::encode::Native>> lbm_sycl_data{sycl_q};
+	saw::data<sch::MacroStruct<T,Desc>, encode::Sycl<saw::encode::Native>> lbm_sycl_macro_data{sycl_q};
+	saw::data<sch::ParticleSpheroidGroup<T,Desc>, encode::Sycl<saw::encode::Native>> lbm_sycl_parts_data{sycl_q};
+	sycl_q.wait();
+
+	{
+		auto eov = dev.copy_to_device(*lbm_data_ptr,lbm_sycl_data);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+	{
+		auto eov = dev.copy_to_device(*lbm_macro_data_ptr,lbm_sycl_macro_data);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+	{
+		auto eov = dev.copy_to_device(*lbm_parts_data_ptr,lbm_sycl_parts_data);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+	sycl_q.wait();
+	auto lsd_view = make_view(lbm_sycl_data);
+	auto lsdm_view = make_view(lbm_sycl_macro_data);
+	auto lsdp_view = make_view(lbm_sycl_parts_data);
+
+	saw::data<sch::UInt64> time_steps{32u*2048ul};
+	auto& info_f = lsd_view.template get<"info">();
+
+	for(saw::data<sch::UInt64> i{0u}; i < time_steps and krun; ++i){
+		// BC + Collision
+		{
+			auto eov = step<T,Desc>(lsd_view,lsdm_view,lsdp_view,i,dev);
+			if(eov.is_error()){
+				return eov;
+			}
+		}
+		sycl_q.wait();
+
+		if( i.get() % 32u == 0u){
+			{
+				auto eov = dev.copy_to_host(lbm_sycl_macro_data,*lbm_macro_data_ptr);
+				if(eov.is_error()){
+					return eov;
+				}
+			}
+			{
+				auto eov = write_vtk_file(out_dir,"m",i.get(), *lbm_macro_data_ptr);
+				if(eov.is_error()){
+					return eov;
+				}
+			}
+		}
+		{
+			auto eov = dev.copy_to_host(lbm_sycl_parts_data,*lbm_parts_data_ptr);
+			if(eov.is_error()){
+				return eov;
+			}
+			auto& p = lbm_parts_data_ptr->template get<"particles">().at({0u}).template get<"rigid_body">();
+			auto& ppos = p.template get<"position">();
+			auto& pacc = p.template get<"acceleration">();
+			std::cout<<"Particle: "<<ppos.at({{0u}}).get()<<", "<<ppos.at({{1u}}).get()<<"; "<<pacc.at({{0u}}).get()<<", "<<pacc.at({{1u}}).get()<<";"<<i.get()<<std::endl;
+		}
+		// Stream
+		sycl_q.submit([&](acpp::sycl::handler& h){
+			component<T,Desc,cmpt::Stream,encode::Sycl<saw::encode::Native>> stream;
+
+			h.parallel_for(acpp::sycl::range<Desc::D>{dim_x,dim_y}, [=](acpp::sycl::id<Desc::D> idx){
+				saw::data<sch::FixedArray<sch::UInt64,Desc::D>> index;
+				for(uint64_t i = 0u; i < Desc::D; ++i){
+					index.at({{i}}).set(idx[i]);
+				}
+				
+				auto info = info_f.at(index);
+				
+				if(info.get() > 0u){
+					stream.apply(lsd_view,index,i);
+				}
+			});
+		}).wait();
+	
+		// EPoll
+		wait.poll();
+		if(print_status){
+			std::cout<<"Status: "<<i.get()<<" of "<<time_steps.get()<<" - "<<(i.template cast_to<sch::Float64>().get() * 100 / time_steps.get())<<"%"<<std::endl;
+			print_status = false;
+		}
+		// print_progress_bar(i.get(), time_steps.get()-1u);
+	}
+
+	// After Loop
+	sycl_q.wait();
+	{
+		auto eov = dev.copy_to_host(lbm_sycl_macro_data,*lbm_macro_data_ptr);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+	{
+		auto eov = write_vtk_file(out_dir,"m",time_steps.get(), *lbm_macro_data_ptr);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+	{
+		auto eov = write_csv_file(out_dir,"m",time_steps.get(), *lbm_macro_data_ptr);
+		if(eov.is_error()){
+			return eov;
+		}
+	}
+
+	sycl_q.wait();
+	return saw::make_void();
+}
+
+using FloatT = kel::lbm::sch::Float64;
+
+int main(int argc, char** argv){
+	auto eov = lbm_main<FloatT,kel::lbm::sch::D2Q9>(argc, argv);
+	if(eov.is_error()){
+		auto& err = eov.get_error();
+		std::cerr<<"[Error] "<<err.get_category();
+		auto err_msg = err.get_message();
+		if(err_msg.size() > 0u){
+			std::cerr<<" - "<<err_msg;
+		}
+		std::cerr<<std::endl;
+		return err.get_id();
+	}
+	return 0;
+}
diff --git a/modules/core/c++/fplbm.hpp b/modules/core/c++/fplbm.hpp
index 4acdd36..1f38f51 100644
--- a/modules/core/c++/fplbm.hpp
+++ b/modules/core/c++/fplbm.hpp
@@ -208,7 +208,7 @@ public:
 		pirb_acc = force_p / pg.template get<"total_mass">().at({});
 
 		for(saw::data<sch::UInt64> i{0u}; i < sub_steps; ++i){
-			//verlet_step_lambda<T,Descriptor::D>(pi,sss);
+			verlet_step_lambda<T,Descriptor::D>(pi,sss);
 		}
 	}
 };
@@ -286,8 +286,7 @@ public:
 
 			// vel_s is technically time the density of the particle?
 
-			force = ( vel_s * rho - vel * rho ) * flip_por / (one + flip_por / two);
-			// force = ( vel_s * rho - vel * rho ) * two * flip_por;
+			force = ( vel_s * rho - vel * rho ) * two * flip_por / (one + flip_por);
 
 			force_p = force_p - force;
 		}, aabb.template get<"a">(), aabb.template get<"b">());
diff --git a/modules/core/c++/psm.hpp b/modules/core/c++/psm.hpp
index c53dbf9..15ad0f8 100644
--- a/modules/core/c++/psm.hpp
+++ b/modules/core/c++/psm.hpp
@@ -7,15 +7,30 @@
 namespace kel {
 namespace lbm {
 namespace cmpt {
-struct PSM {};
+struct PsmReset {};
 struct PsmOneParticle {};
+struct Psm {};
 }
 
+template<typename T, typename Descriptor, typename Encode>
+class component<T, Descriptor, cmpt::PsmReset, Encode> final {
+public:
+	component() = default;
+
+	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& por = porosity_f.at(index);
+		por.at({}) = 1.0;
+	}
+};
+
 /**
  * PSM collision operator for LBM
  */
 template<typename T, typename Descriptor, typename Encode>
-class component<T, Descriptor, cmpt::PSM, Encode> {
+class component<T, Descriptor, cmpt::Psm, Encode> {
 private:
 	saw::data<T> relaxation_;
 	saw::data<T> frequency_;
@@ -86,80 +101,119 @@ public:
 template<typename T, typename Descriptor, typename Encode>
 class component<T, Descriptor, cmpt::PsmOneParticle, Encode> final {
 private:
-	saw::data<T> relaxation_;
-	saw::data<T> frequency_;
 public:
-	component(
-		typename saw::native_data_type<T>::type relaxation__
-	):
-		relaxation_{relaxation__}
-	{
-		saw::data<T> one;
-		one = 1.0;
-		frequency_ = one / relaxation_;
-	}
+	component() = default;
 
 	template<typename CellFieldSchema, typename MacroFieldSchema, typename ParticleSchema>
-	void apply(const saw::data<CellFieldSchema, Encode>& field, const saw::data<MacroFieldSchema,Encode>& macros, const saw::data<ParticleSchema,Encode>& particles, saw::data<sch::FixedArray<sch::UInt64,1u>> index, saw::data<sch::UInt64> time_step) const {
+	void apply(const saw::data<CellFieldSchema, Encode>& field, const saw::data<MacroFieldSchema,Encode>& macros, const saw::data<ParticleSchema,Encode>& pg, saw::data<sch::FixedArray<sch::UInt64,1u>> index, saw::data<sch::UInt64> time_step, saw::data<sch::UInt64> sub_steps) const {
 	
 		using dfi = df_info<T,Descriptor>;
 		bool is_even = ((time_step.get() % 2) == 0);
+		
+		saw::data<sch::Scalar<T>> one;
+		one.at({}) = 1.0;
 
 		auto& dfs_old_f = (is_even) ? field.template get<"dfs_old">() : field.template get<"dfs">();
-		auto& porous_f = macros.template get<"porosity">();
 
+		auto& por_f = macros.template get<"porosity">();
 		auto& rho_f = macros.template get<"density">();
 		auto& vel_f = macros.template get<"velocity">();
-		
-		saw::data<sch::Scalar<T>>& rho = rho_f.at(index);
-		saw::data<sch::Vector<T,Descriptor::D>>& vel = vel_f.at(index);
-
-		compute_rho_u<T,Descriptor>(dfs_old_f.at(index),rho,vel);
-		
-		auto eq = equilibrium<T,Descriptor>(rho,vel);
-
-		saw::data<T> one{1.0};
-		auto& porous = porous_f.at(index);
-		auto flip_porous = one - porous.at({});
-
-		auto& dfs = dfs_old_f.at(index);
-
-		auto dfs_cpy = dfs;
-
-		for(uint64_t i = 0u; i < Descriptor::Q; ++i){
-			uint64_t i_opp = dfi::opposite_index[i];
-			dfs.at({i}) = dfs_cpy.at({i}) + frequency_ * (eq.at(i) - dfs_cpy.at({i})) * porous.at({}) + (dfs_cpy.at({i_opp}) - dfs_cpy.at({i}) ) * flip_porous;
-		}
-
 		auto& force_f = macros.template get<"force">();
-		auto& force = force_f.at(index);
-		for(uint64_t k{0u}; k < Descriptor::D; ++k){
-			force.at({{k}}).set(0);
-		}
-
-		/////////
-		saw::data<sch::Vector<T,Descriptor::D>> momentum;
-		for(uint64_t i = 0u; i < Descriptor::Q; ++i){
-			
-			saw::data<sch::Vector<T,Descriptor::D>> e_i;
-			saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> n_ind_i;
-			for(uint64_t k{0u}; k < Descriptor::D; ++k){
-				e_i.at({{k}}) = dfi::directions[i][k];
-				n_ind_i.at({k}) = (dfi::directions[i])[k];
+	
+		{
+			auto parts = pg.template get<"particles">();
+			auto parts_size = parts.meta().at({0u});
+
+			auto& p_coll = pg.template get<"collision">().at({});
+			auto& p_rad = p_coll.template get<"radius">();
+
+			auto& pi = parts.at(index);
+			auto& pirb = pi.template get<"rigid_body">();
+			saw::data<sch::Vector<T,Descriptor::D>>& pirb_pos = pirb.template get<"position">();
+			auto& pirb_pos_old = pirb.template get<"position_old">();
+				
+			saw::data<sch::Scalar<T>> ts;
+			ts.at({}) = one.at({}) / sub_steps.template cast_to<T>();
+
+			saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> start;
+			saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> stop;
+
+			auto eo_aabb = particle_aabb<typename ParticleSchema::ValueType>::calculate(pg,{{0u}},vel_f.meta());
+			if(eo_aabb.is_error()){
+				return;
 			}
+			auto& aabb = eo_aabb.get_value();
 
-			uint64_t i_opp = dfi::opposite_index[i];
+			/// Ok, I iterate over the space which covers our particle? So lower bounds to upper bounds
+			start = aabb.template get<"a">();
+			stop = aabb.template get<"b">();
 
-			saw::data<T> dfs_added = dfs.at({i}) - dfs_old_f.at(n_ind_i).at({i_opp});
-			saw::data<sch::Scalar<T>> dfs_added_v;
-			dfs_added_v.at({}) = dfs_added;
-			auto ei_dfs = e_i * dfs_added_v;
+			saw::data<sch::Vector<T,Descriptor::D>> force_p;
+			for(uint64_t i{0u}; i < Descriptor::D; ++i){
+				force_p.at({{i}}) = 0.0;
+			}
+			auto vel_p_old = (pirb_pos-pirb_pos_old) / ts;
 
-			momentum = momentum + ei_dfs;
+			iterator<Descriptor::D>::apply([&](const auto& index_f) -> void{
+				// ask for the d_k value here.
+				// For every value im iterating over I need sth
+				// std::cout<<"Pos: "<<index.at({0u}).get()<<" "<<index.at({1u}).get()<<std::endl;
+			
+				auto& dfs = dfs_old_f.at(index_f);
+				saw::data<sch::Vector<T,Descriptor::D>> rel_dist = saw::math::vectorize_data(index_f).template cast_to<T>() - pirb_pos;
+				saw::data<sch::Scalar<T>> eps;
+				eps.at({}) = 1.5f;
+				
+				auto& por = por_f.at(index_f);
+				por = particle_porosity<T,Descriptor::D,1u,por::ParticleSpheroid<T>>::calculate(rel_dist,p_rad,eps);
+
+				if(por.at({}).get() >= 1.0f){
+					return;
+				}
+
+				saw::data<sch::Vector<T,Descriptor::D>> momentum;
+				for(uint64_t i{0u}; i < Descriptor::D; ++i){
+					momentum.at({{i}}) = 0.0;
+				}
+
+				for(uint64_t i{0u}; i < Descriptor::Q; ++i){
+					saw::data<sch::Vector<T,Descriptor::D>> e_i;
+					saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> n_ind_i;
+					for(uint64_t k{0u}; k < Descriptor::D; ++k){
+						e_i.at({{k}}) = (dfi::directions[i])[k];
+						n_ind_i.at({k}) = index_f.at({k}) + (dfi::directions[i])[k];
+					}
+
+					uint64_t i_opp = dfi::opposite_index[i];
+
+					auto u_p_e = saw::math::dot(e_i,vel_p_old);
+
+					saw::data<T> dfs_added = dfs.at({i})*(saw::data<T>{1}-u_p_e.at({})) + dfs_old_f.at(n_ind_i).at({i_opp})*(saw::data<T>{1}+u_p_e.at({}));
+					saw::data<sch::Scalar<T>> dfs_added_v;
+					dfs_added_v.at({}) = dfs_added;
+					auto ei_dfs = e_i * dfs_added_v;
+
+					momentum = momentum + ei_dfs;
+				}
+				// technically needs to adjust for rotation as well
+				
+				auto& force = force_f.at(index_f);
+				auto& rho = rho_f.at(index_f);
+				// To Fluid
+				
+				auto flip_por = one - por;
+				force = momentum * flip_por;
+				// To Particle
+				force_p = force_p - force;
+			},start,stop);
+			
+			auto& pirb_acc = pirb.template get<"acceleration">();
+			pirb_acc = force_p / pg.template get<"total_mass">().at({});
+
+			for(saw::data<sch::UInt64> i{0u}; i < sub_steps; ++i){
+				verlet_step_lambda<T,Descriptor::D>(pi,ts);
+			}
 		}
-		
-		// Set Force
-		force = momentum * porous_f.at(index);
 	}
 };
 
-- 
cgit v1.2.3


From 7d094fe719923db5eb6b30edcc4fa01c6ce2cc2e Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Fri, 7 Aug 2026 12:34:22 +0200
Subject: Cleaning up code

---
 modules/core/c++/abstract/data.hpp              | 89 +++++++++++++++++++++++++
 modules/core/c++/abstract/error.hpp             |  2 +-
 modules/core/c++/particle/aabb.hpp              |  1 -
 modules/core/c++/particle/cuboid/aabb.hpp       | 40 +++++++++++
 modules/core/c++/particle/cuboid/common.hpp     | 10 +++
 modules/core/c++/particle/cuboid/particle.hpp   |  9 +++
 modules/core/c++/particle/cuboid/porosity.hpp   | 10 +++
 modules/core/c++/particle/particle.hpp          |  4 +-
 modules/core/c++/particle/spheroid/particle.hpp |  9 +++
 9 files changed, 170 insertions(+), 4 deletions(-)
 create mode 100644 modules/core/c++/particle/cuboid/aabb.hpp
 create mode 100644 modules/core/c++/particle/cuboid/common.hpp
 create mode 100644 modules/core/c++/particle/cuboid/particle.hpp
 create mode 100644 modules/core/c++/particle/cuboid/porosity.hpp
 create mode 100644 modules/core/c++/particle/spheroid/particle.hpp

diff --git a/modules/core/c++/abstract/data.hpp b/modules/core/c++/abstract/data.hpp
index f1ae5a7..327fb63 100644
--- a/modules/core/c++/abstract/data.hpp
+++ b/modules/core/c++/abstract/data.hpp
@@ -10,8 +10,97 @@ class data final {};
 
 template<typename T, uint64_t N>
 class data<sch::Primitive<T,N>,Encode> final {
+public:
+	using Schema = sch::Primitive<T,N>;
+	using Encode = Encode;
 private:
+	native_data_type<Schema>::type value_;
 public:
+	data():
+		value_{}
+	{}
+
+	data(native_data_type<Schema>::type value__):
+		value_{value__}
+	{}
+
+	constexpr auto get() const {
+		return value_;
+	}
+
+	void set(native_data_type value__){
+		value_ = value__;
+	}
+
+	constexpr bool operator==(const data<Schema,Encode>& rhs) const {
+		return value_ == rhs.value_;
+	}
+	
+	constexpr bool operator!=(const data<Schema,Encode>& rhs) const {
+		return value_ != rhs.value_;
+	}
+	
+	constexpr bool operator>(const data<Schema,Encode>& rhs) const {
+		return value_ > rhs.value_;
+	}
+	
+	constexpr bool operator<(const data<Schema,Encode>& rhs) const {
+		return value_ < rhs.value_;
+	}
+	
+	constexpr bool operator>=(const data<Schema,Encode>& rhs) const {
+		return value_ >= rhs.value_;
+	}
+	
+	constexpr bool operator<=(const data<Schema,Encode>& rhs) const {
+		return value_ >= rhs.value_;
+	}
+	
+	constexpr bool equals(const data<Schema,Encode>& rhs) const {
+		return (*this) == rhs;
+	}
+
+	data<Schema,Encode> operator+(const data<Schema,Encode>& rhs) const {
+		return {value_ + rhs.value_};
+	}
+	
+	data<Schema,Encode> operator-(const data<Schema,Encode>& rhs) const {
+		return {value_ - rhs.value_};
+	}
+	
+	data<Schema,Encode> operator*(const data<Schema,Encode>& rhs) const {
+		return {value_ * rhs.value_};
+	}
+	
+	data<Schema,Encode> operator/(const data<Schema,Encode>& rhs) const {
+		return {value_ / rhs.value_};
+	}
+	
+	data<Schema,Encode>& operator+=(const data<Schema,Encode>& rhs) {
+		value_ += rhs.value_;
+		return *this
+	}
+	
+	data<Schema,Encode>& operator-=(const data<Schema,Encode>& rhs) {
+		value_ -= rhs.value_;
+		return *this
+	}
+	
+	data<Schema,Encode>& operator*=(const data<Schema,Encode>& rhs) {
+		value_ *= rhs.value_;
+		return *this
+	}
+	
+	data<Schema,Encode>& operator/=(const data<Schema,Encode>& rhs) {
+		value_ /= rhs.value_;
+		return *this
+	}
+
+	template<typename T>
+	data<T,Encode> cast_to() const {
+		data<T,Encode> val{static_cast<typename native_data_type<T>::type>(value_)};
+		return val;
+	}
 };
 
 
diff --git a/modules/core/c++/abstract/error.hpp b/modules/core/c++/abstract/error.hpp
index 19917de..94a2c35 100644
--- a/modules/core/c++/abstract/error.hpp
+++ b/modules/core/c++/abstract/error.hpp
@@ -305,7 +305,7 @@ public:
 
 /**
  * This tries to catch cases where error starts including itself as a type which can happen in more complicated cases.
- * So this acts as a type safe guard.
+ * So this acts as a type safe guard in case internal handling fails to treat conversion correctly.
  */
 template <typename T> class error_or<error_or<T>> {
 private:
diff --git a/modules/core/c++/particle/aabb.hpp b/modules/core/c++/particle/aabb.hpp
index da39ec2..e4c930b 100644
--- a/modules/core/c++/particle/aabb.hpp
+++ b/modules/core/c++/particle/aabb.hpp
@@ -26,7 +26,6 @@ public:
 	static constexpr saw::error_or<saw::data<AABB>> calculate(const saw::data<Sch,Encode>& p_grp, const saw::data<sch::FixedArray<sch::UInt64,1u>>& index, const saw::data<sch::FixedArray<sch::UInt64,D>>& meta){
 		static_assert(PC > 0u, "Can't calculate from no particles");
 		if(not (index.at({{0u}}).get() < PC) ){
-			std::cerr.flush();
 			return saw::make_error<saw::err::critical>("Too large i in particle_aabb");
 		}
 
diff --git a/modules/core/c++/particle/cuboid/aabb.hpp b/modules/core/c++/particle/cuboid/aabb.hpp
new file mode 100644
index 0000000..502132a
--- /dev/null
+++ b/modules/core/c++/particle/cuboid/aabb.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include "common.hpp"
+#include "../aabb.hpp"
+
+namespace kel {
+namespace lbm {
+
+template<typename T, uint64_t D, uint64_t PC>
+class particle_aabb<
+	sch::ParticleGroup<T,D,PC,coll::Cuboid<T>>
+> final {
+public:
+	using Schema = sch::ParticleGroup<T,D,PC,coll::Cuboid<T>>;
+
+	using AABB = sch::Struct<
+		sch::Member<sch::FixedArray<sch::UInt64,D>, "a">,
+		sch::Member<sch::FixedArray<sch::UInt64,D>, "b">
+	>;
+
+public:
+	template<typename Sch, typename Encode>
+	static constexpr saw::error_or<saw::data<AABB>> calculate(const saw::data<Sch,Encode>& pg, const saw::data<sch::FixedArray<sch::UInt64,1u>>& index, const saw::data<sch::FixedArray<sch::UInt64,D>>& meta){
+		static_assert(PC > 0u, "Can't calculate from no particle");
+		if(not (index.at({0u}).get() < PC)){
+			return saw::make_error<saw::err::critical>("Too large i in particle_aabb coll::Cuboid<T>");
+		}
+
+		saw::data<AABB> aabb;
+		auto& parts = pg.template get<"particles">();
+		auto& pi = parts.at(index);
+		auto& pirb = pi.template get<"rigid_body">();
+
+		/// TODO
+
+		return aabb;
+	}
+};
+}
+}
diff --git a/modules/core/c++/particle/cuboid/common.hpp b/modules/core/c++/particle/cuboid/common.hpp
new file mode 100644
index 0000000..a859cbe
--- /dev/null
+++ b/modules/core/c++/particle/cuboid/common.hpp
@@ -0,0 +1,10 @@
+#pragma once
+
+namespace kel {
+namespace lbm {
+namespace coll {
+template<typename T>
+struct Cuboid {};
+}
+}
+}
diff --git a/modules/core/c++/particle/cuboid/particle.hpp b/modules/core/c++/particle/cuboid/particle.hpp
new file mode 100644
index 0000000..e19d543
--- /dev/null
+++ b/modules/core/c++/particle/cuboid/particle.hpp
@@ -0,0 +1,9 @@
+#pragma once
+
+#include "common.hpp"
+#include "porosity.hpp"
+
+namespace kel {
+namespace lbm {
+}
+}
diff --git a/modules/core/c++/particle/cuboid/porosity.hpp b/modules/core/c++/particle/cuboid/porosity.hpp
new file mode 100644
index 0000000..bccfebf
--- /dev/null
+++ b/modules/core/c++/particle/cuboid/porosity.hpp
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "common.hpp"
+#include "../porosity.hpp"
+
+namespace kel {
+namespace lbm {
+
+}
+}
diff --git a/modules/core/c++/particle/particle.hpp b/modules/core/c++/particle/particle.hpp
index a3669b4..21b4b34 100644
--- a/modules/core/c++/particle/particle.hpp
+++ b/modules/core/c++/particle/particle.hpp
@@ -82,8 +82,8 @@ saw::data<sch::ParticleGroup<T, D, PartAmount, coll::Spheroid<T>>> create_sphero
 		total_mass.at({}) = rad_d * rad_d * density.at({}) * 3.141592;
 	}else if constexpr ( D == 3u ){
 		
-	}else if constexpr ( D== 1u ){
-
+	}else if constexpr ( D == 1u ){
+		total_mass.at({}) = rad_d * 2.0;
 	}
 	std::cout<<"Total Mass: "<<total_mass.at({}).get()<<std::endl;
 
diff --git a/modules/core/c++/particle/spheroid/particle.hpp b/modules/core/c++/particle/spheroid/particle.hpp
new file mode 100644
index 0000000..9c0912e
--- /dev/null
+++ b/modules/core/c++/particle/spheroid/particle.hpp
@@ -0,0 +1,9 @@
+#pragma once
+
+namespace kel {
+namespace lbm {
+namespace coll {
+
+}
+}
+}
-- 
cgit v1.2.3