From ae8711ba90ac2a47ea7654dc873927fb2783ff91 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Fri, 18 Apr 2025 16:25:30 +0200
Subject: wip rendering in terminal and extracting example code to files

---
 c++/descriptor.hpp        | 18 ++++++++++++++++++
 c++/equilibrium.hpp       |  6 ++++++
 c++/macroscopic.hpp       | 32 ++++++++++++++++++++++++++++++++
 c++/term_renderer.hpp     |  7 +++++++
 examples/cavity_2d.cpp    | 26 +-------------------------
 examples/poiseulle_2d.cpp |  8 ++++++++
 6 files changed, 72 insertions(+), 25 deletions(-)
 create mode 100644 c++/macroscopic.hpp
 create mode 100644 c++/term_renderer.hpp
 create mode 100644 examples/poiseulle_2d.cpp

diff --git a/c++/descriptor.hpp b/c++/descriptor.hpp
index 014327c..aa8c943 100644
--- a/c++/descriptor.hpp
+++ b/c++/descriptor.hpp
@@ -152,6 +152,24 @@ public:
 	static constexpr typename saw::native_data_type<T>::type inv_cs2 = 3.0;
 	static constexpr typename saw::native_data_type<T>::type cs2 = 1./3.;
 };
+
+template<typename Schema>
+class cell_schema_builder {
+private:
+	saw::schema_factory<Schema> factory_struct_;
+public:
+	cell_schema_builder() = default;
+
+	cell_schema_builder(saw::schema_factory<Schema> inp):
+		factory_struct_{inp}
+	{}
+
+	template<typename TA, saw::string_literal KA>
+	constexpr auto require() const noexcept {
+		return {factory_struct_.add_maybe()};
+	}
+};
+ 
 }
 }
 
diff --git a/c++/equilibrium.hpp b/c++/equilibrium.hpp
index ac36dbc..bb55d00 100644
--- a/c++/equilibrium.hpp
+++ b/c++/equilibrium.hpp
@@ -13,14 +13,20 @@ saw::data<sch::FixedArray<T, Descriptor::Q>> equilibrium(saw::data<T> rho, saw::
 	//  0.0
 	//  / \
 	//  | |
+	//
+	//  Velocity * Velocity meaning || vel ||_2^2 or <vel,vel>_2
 	saw::data<T> vel_vel{0.0};
 	for(uint64_t j = 0u; j < Descriptor::D; ++j){
 		vel_vel = vel_vel + vel.at(j) * vel.at(j);
 	}
 
+	/**
+	 * Calculate equilibrium
+	 */
 	for(uint64_t i = 0u; i < eq.template get_dim_size<0u>(); ++i){
 		saw::data<T> vel_c{};
 		for(uint64_t j = 0u; j < Descriptor::D; ++j){
+			// <vel,c_i>_2
 			vel_c = vel_c + (vel.at(j) * saw::data<T>{static_cast<saw::native_data_type<T>::type>(dfi::directions[i][j])});
 		}
 
diff --git a/c++/macroscopic.hpp b/c++/macroscopic.hpp
new file mode 100644
index 0000000..608b89e
--- /dev/null
+++ b/c++/macroscopic.hpp
@@ -0,0 +1,32 @@
+#pragma once
+
+namespace kel {
+namespace lbm {
+/**
+ * Calculate the macroscopic variables rho and u in Lattice Units.
+ */
+template<typename Desc>
+void compute_rho_u (
+		const saw::data<sch::DfCell<Desc>>& dfs,
+		typename saw::native_data_type<sch::T>::type& rho,
+		std::array<typename saw::native_data_type<sch::T>::type, 2>& vel
+	)
+{
+	using dfi = df_info<sch::T, Desc>;
+
+	rho = 0;
+	std::fill(vel.begin(), vel.end(), 0);
+
+	for(size_t j = 0; j < Desc::Q; ++j){
+		rho += dfs(j).get();
+		for(size_t i = 0; i < Desc::D; ++i){
+			vel[i] += dfi::directions[j][i] * dfs(j).get();
+		}
+	}
+
+	for(size_t i = 0; i < Desc::D; ++i){
+		vel[i] /= rho;
+	}
+}
+}
+}
diff --git a/c++/term_renderer.hpp b/c++/term_renderer.hpp
new file mode 100644
index 0000000..f675a99
--- /dev/null
+++ b/c++/term_renderer.hpp
@@ -0,0 +1,7 @@
+#pragma once
+
+namespace kel {
+namespace lbm {
+
+}
+}
diff --git a/examples/cavity_2d.cpp b/examples/cavity_2d.cpp
index 3e2e064..5085635 100644
--- a/examples/cavity_2d.cpp
+++ b/examples/cavity_2d.cpp
@@ -1,4 +1,5 @@
 #include "../c++/descriptor.hpp"
+#include "../c++/macroscopic.hpp"
 
 /**
  */
@@ -46,31 +47,6 @@ using CellStruct = Struct<
 using CavityFieldD2Q9 = CellField<D2Q9, CellStruct<D2Q9>>;
 }
 
-/**
- * Calculate the macroscopic variables rho and u in Lattice Units.
- */
-template<typename Desc>
-void compute_rho_u (
-		saw::data<sch::DfCell<Desc>>& dfs,
-		typename saw::native_data_type<sch::T>::type& rho,
-		std::array<typename saw::native_data_type<sch::T>::type, 2>& vel
-	)
-{
-	using dfi = df_info<sch::T, Desc>;
-
-	rho = 0;
-	std::fill(vel.begin(), vel.end(), 0);
-
-	for(size_t i = 0; i < Desc::Q; ++i){
-		rho += dfs(i).get();
-		vel[0] += dfi::directions[i][0] * dfs(i).get();
-		vel[1] += dfi::directions[i][1] * dfs(i).get();
-	}
-
-	vel[0] /= rho;
-	vel[1] /= rho;
-}
-
 /**
  * Unsure if feasible. I would have a rho normalization on the dfs and then I would use the const rho_computation
  */
diff --git a/examples/poiseulle_2d.cpp b/examples/poiseulle_2d.cpp
new file mode 100644
index 0000000..be3efbc
--- /dev/null
+++ b/examples/poiseulle_2d.cpp
@@ -0,0 +1,8 @@
+#include "../c++/descriptor.hpp"
+
+#include <forstio/codec/data.hpp>
+
+int main(int argc, char** argv){
+
+	return 0;
+}
-- 
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