From 1fbfad0b44b5a3689d54d2b43940e94388b90803 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Sat, 30 Aug 2025 11:25:09 +0200
Subject: Adding dangling changes

---
 c++/converter.hpp                           |  16 +++++++++--
 c++/particle/geometry/.circle.hpp.kate-swp  | Bin 0 -> 62 bytes
 default.nix                                 |   2 +-
 examples/poiseulle_particles_channel_2d.cpp |  40 ++++++++++++++++++++--------
 tests/converter.cpp                         |   1 -
 5 files changed, 44 insertions(+), 15 deletions(-)
 create mode 100644 c++/particle/geometry/.circle.hpp.kate-swp

diff --git a/c++/converter.hpp b/c++/converter.hpp
index 6e0a7a6..5c19c68 100644
--- a/c++/converter.hpp
+++ b/c++/converter.hpp
@@ -1,10 +1,18 @@
 #pragma once
 
 #include "lbm_unit.hpp"
+#include "descriptor.hpp"
 
 namespace kel {
 namespace lbm {
 
+namespace sch {
+using namespace saw::schema;
+}
+
+/**
+ * Helps converting from SI types to LBM types
+ */
 template<typename T>
 class converter {
 private:
@@ -59,9 +67,13 @@ public:
 	}
 
 	saw::data<sch::LbmKinematicViscosity<T>> kinematic_viscosity_si_to_lbm (const saw::data<sch::SiKinematicViscosity<T>>& kin_si) const {
-		return kin_si / (meter_conv_ * meter_conv_) * second_conv_;
+		return (kin_si / (meter_conv_ * meter_conv_)) * second_conv_;
 	}
-};
 
+	template<typename Desc>
+	saw::data<sch::Pure<T>> kinematic_viscosity_si_to_tau(const saw::data<sch::SiKinematicViscosity<T>>& kin_si) const {
+		return saw::data<sch::Pure<T>>{saw::data<typename saw::unit_division<sch::Pure<T>, sch::LbmKinematicViscosity<T>>::Schema >{df_info<T,Desc>::inv_cs2} * kinematic_viscosity_si_to_lbm(kin_si) + saw::data<sch::Pure<T>>{0.5}};
+	}
+};
 }
 }
diff --git a/c++/particle/geometry/.circle.hpp.kate-swp b/c++/particle/geometry/.circle.hpp.kate-swp
new file mode 100644
index 0000000..b28db57
Binary files /dev/null and b/c++/particle/geometry/.circle.hpp.kate-swp differ
diff --git a/default.nix b/default.nix
index d92720d..883b70e 100644
--- a/default.nix
+++ b/default.nix
@@ -1,6 +1,6 @@
 { pkgs ? import <nixpkgs> {}
 , stdenv ? pkgs.llvmPackages_19.stdenv
-, clang-tools ? pkgs.clang-tools_16
+, clang-tools ? pkgs.clang-tools_19
 }:
 
 let
diff --git a/examples/poiseulle_particles_channel_2d.cpp b/examples/poiseulle_particles_channel_2d.cpp
index f6a5dd0..e2d7200 100644
--- a/examples/poiseulle_particles_channel_2d.cpp
+++ b/examples/poiseulle_particles_channel_2d.cpp
@@ -9,7 +9,6 @@
 
 #include <cmath>
 
-
 namespace kel {
 namespace lbm {
 namespace sch {
@@ -619,7 +618,7 @@ int main(int argc, char** argv){
 
 	uint64_t lbm_steps = 4096u * 4u;
 	for(uint64_t i = 0u; i < lbm_steps; ++i){
-		print_progress_bar(i+1u,lbm_steps);
+		print_progress_bar(i,lbm_steps-1u);
 		bool even_step = ((i % 2u) == 0u);
 
 		{
@@ -642,20 +641,39 @@ int main(int argc, char** argv){
 
 				auto& p_rb = p.template get<"rigid_body">();
 				auto& p_pos = p_rb.template get<"position">();
+				auto& p_mask = p_rb.template get<"mask">();
+				auto& p_mask_grid = p_mask.template get<"grid">();
+				auto p_mask_grid_dims = p_mask_grid.dims();
+
+				saw::data<sch::Vector<sch::T,2u>> p_mask_grid_shift;
+				p_mask_grid_shift.at({{0u}}) = (p_mask_grid_dims.at({0u}).template cast_to<sch::T>() - 1.0) / 2.0;
+				p_mask_grid_shift.at({{1u}}) = (p_mask_grid_dims.at({1u}).template cast_to<sch::T>() - 1.0) / 2.0;
 
+				auto p_pos_lie = p_pos + mask_shift;
+
+				// Cast down to get lower corner.
+				// Before casting shift by 0.5 for closest pick
 				saw::data<sch::FixedArray<sch::UInt64,2u>> p_cell_pos {{
-					static_cast<uint64_t>(p_pos.at({{0u}}).get()+0.5),
-					static_cast<uint64_t>(p_pos.at({{1u}}).get()+0.5)
+					static_cast<uint64_t>(p_pos_lie.at({{0u}}).get()+0.5),
+					static_cast<uint64_t>(p_pos_lie.at({{1u}}).get()+0.5)
 				}};
 
-				if(p_cell_pos.at({0u}) >= dim.at({0u}) ){
-					p_cell_pos.at({0u}).set(dim.at({0u}).get() - 1u );
-				}
-				if(p_cell_pos.at({1u}) >= dim.at({1u}) ){
-					p_cell_pos.at({1u}).set(dim.at({1u}).get() - 1u );
-				}
+				// Iterate
+				iterate_over([&](const saw::data<sch::FixedArray<sch::UInt64,2u>>& index){
+
+					saw::data<sch::Vector<sch::T,2u>> index_shift;
+					index_shift.at({{0u}}) = index.at({0u}).template cast_to<sch::T>() - p_mask_grid_shift.at({{0u}});
+					index_shift.at({{1u}}) = index.at({0u}).template cast_to<sch::T>() - p_mask_grid_shift.at({{1u}});
+
+					if(p_cell_pos.at({0u}) >= dim.at({0u}) ){
+						p_cell_pos.at({0u}).set(dim.at({0u}).get() - 1u );
+					}
+					if(p_cell_pos.at({1u}) >= dim.at({1u}) ){
+						p_cell_pos.at({1u}).set(dim.at({1u}).get() - 1u );
+					}
 
-				macros(p_cell_pos).template get<"particle">().set(i.get() + 1u);
+					macros(p_cell_pos).template get<"particle">().set(i.get() + 1u);
+				}, {{0u,0u}}, p_mask_grid_dims);
 			}
 
 			{
diff --git a/tests/converter.cpp b/tests/converter.cpp
index d7f3d67..4fc536f 100644
--- a/tests/converter.cpp
+++ b/tests/converter.cpp
@@ -21,7 +21,6 @@ SAW_TEST("Si Meter to Lbm Meter"){
 	saw::data<sch::SiMeter<sch::T>> si_m{1.0};
 
 	auto lbm_m = converter.meter_si_to_lbm(si_m);
-
 	SAW_EXPECT(lbm_m.handle().get() == 10.0, "Correct si to lbm conversion");
 }
 }
-- 
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