From b9aacd9c2fdc61721c8ca3e1b40ebc92daa3772e Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Wed, 5 Nov 2025 13:38:04 +0100
Subject: Reworking structure

---
 lib/core/c++/descriptor.hpp | 414 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 414 insertions(+)
 create mode 100644 lib/core/c++/descriptor.hpp

(limited to 'lib/core/c++/descriptor.hpp')

diff --git a/lib/core/c++/descriptor.hpp b/lib/core/c++/descriptor.hpp
new file mode 100644
index 0000000..c6938e3
--- /dev/null
+++ b/lib/core/c++/descriptor.hpp
@@ -0,0 +1,414 @@
+#pragma once
+
+#include <forstio/codec/data.hpp>
+#include <forstio/codec/data_math.hpp>
+#include <forstio/codec/schema_factory.hpp>
+
+namespace kel {
+namespace lbm {
+namespace sch {
+using namespace saw::schema;
+
+template<uint64_t DV, uint64_t QV>
+struct Descriptor {
+	static constexpr uint64_t D = DV;
+	static constexpr uint64_t Q = QV;
+};
+
+template<typename Sch, typename Desc, uint64_t SC_V, uint64_t DC_V, uint64_t QC_V>
+struct Cell {
+	using Descriptor = Desc;
+	static constexpr uint64_t SC = SC_V;
+	static constexpr uint64_t DC = DC_V;
+	static constexpr uint64_t QC = QC_V;
+	static constexpr uint64_t Size = SC + Desc::D * DC + Desc::Q * QC;
+};
+
+template<typename Desc, typename Cell>
+struct CellField{
+	using Descriptor = Desc;
+};
+
+template<typename Desc, typename... CellFieldTypes, saw::string_literal... CellFieldNames>
+struct CellField<
+	Desc,
+	Struct<
+		Member<CellFieldTypes, CellFieldNames>...
+	>
+> {
+	using Descriptor = Desc;
+};
+
+template<typename Desc, typename... CellFieldMembers>
+struct CellFieldStruct {
+	using Descriptor = Desc;
+	// using MetaSchema = FixedArray<UInt64, Desc::D>;
+};
+
+}
+
+template<typename T, typename Desc>
+class df_info{};
+
+template<typename T> 
+class df_info<T,sch::Descriptor<1,3>> {
+public:
+	using Descriptor = sch::Descriptor<1,3>;
+
+	static constexpr uint64_t D = 1u;
+	static constexpr uint64_t Q = 3u;
+
+	static constexpr std::array<std::array<int32_t,D>,Q> directions = {{
+		{ 0},
+		{-1},
+		{ 1}
+	}};
+
+	static constexpr std::array<typename saw::native_data_type<T>::type, Q> weights = {
+		2./3.,
+		1./6.,
+		1./6.
+	};
+
+	static constexpr std::array<uint64_t,Q> opposite_index = {
+		0,2,1
+	};
+	
+	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.;
+};
+
+/**
+ * D2Q5 Descriptor
+ */
+template<typename T>
+class df_info<T,sch::Descriptor<2, 5>> {
+public:
+	using Descriptor = sch::Descriptor<2,5>;
+
+	static constexpr uint64_t D = 2u;
+	static constexpr uint64_t Q = 5u;
+
+	static constexpr std::array<std::array<int32_t, D>, Q> directions = {{
+		{ 0, 0},
+		{-1, 0},
+		{ 1, 0},
+		{ 0,-1},
+		{ 0, 1},
+	}};
+
+	static constexpr std::array<typename saw::native_data_type<T>::type,Q> weights = {
+		1./3.,
+		1./6.,
+		1./6.,
+		1./6.,
+		1./6.
+	};
+
+	static constexpr std::array<uint64_t,Q> opposite_index = {
+		0,
+		2,
+		1,
+		4,
+		3
+	};
+
+	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 T>
+class df_info<T,sch::Descriptor<2, 9>> {
+public:
+	using Descriptor = sch::Descriptor<2,9>;
+	
+	static constexpr uint64_t D = 2u;
+	static constexpr uint64_t Q = 9u;
+
+	static constexpr std::array<std::array<int32_t, D>, Q> directions = {{
+		{ 0, 0},
+		{-1, 0},
+		{ 1, 0},
+		{ 0,-1},
+		{ 0, 1},
+		{-1,-1},
+		{ 1, 1},
+		{-1, 1},
+		{ 1,-1}
+	}};
+
+	static constexpr std::array<typename saw::native_data_type<T>::type,Q> weights = {
+		4./9.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./36.,
+		1./36.,
+		1./36.,
+		1./36.
+	};
+
+	static constexpr std::array<uint64_t,Q> opposite_index = {
+		0,
+		2,
+		1,
+		4,
+		3,
+		6,
+		5,
+		8,
+		7
+	};
+	
+	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 T>
+class df_info<T,sch::Descriptor<3, 27>> {
+public:
+	using Descriptor = sch::Descriptor<3,27>;
+
+	static constexpr uint64_t D = 3u;
+	static constexpr uint64_t Q = 27u;
+
+	static constexpr std::array<std::array<int32_t, D>, Q> directions = {{
+		{ 0, 0, 0},  // 0
+		{-1, 0, 0},  // 1
+		{ 1, 0, 0},  // 2
+		// Expand into 2D
+		{ 0, -1, 0}, // 3
+		{-1, -1, 0}, // 4
+		{ 1, -1, 0}, // 5
+		{ 0, 1, 0},  // 6
+		{-1, 1, 0},  // 7
+		{ 1, 1, 0},  // 8
+		// Expand into 3D
+		{ 0, 0, -1}, // 9
+		{-1, 0, -1}, // 10
+		{ 1, 0, -1}, // 11
+		{ 0, -1, -1},// 12
+		{-1, -1, -1},// 13
+		{ 1, -1, -1},// 14
+		{ 0, 1, -1}, // 15
+		{-1, 1, -1}, // 16
+		{ 1, 1, -1}, // 17
+		{ 0, 0, 1},  // 18
+		{-1, 0, 1},  // 19
+		{ 1, 0, 1},  // 20
+		{ 0, -1, 1}, // 21
+		{-1, -1, 1}, // 22
+		{ 1, -1, 1}, // 23
+		{ 0, 1, 1},  // 24
+		{-1, 1, 1},  // 25
+		{ 1, 1, 1}   // 26
+	}};
+
+	static constexpr std::array<typename saw::native_data_type<T>::type,Q> weights = {
+		8./27.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./36.,
+		1./36.,
+		1./36.,
+		1./36.,
+		8./27.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./36.,
+		1./36.,
+		1./36.,
+		1./36.,
+		8./27.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./9.,
+		1./36.,
+		1./36.,
+		1./36.,
+		1./36.
+	};
+
+	static constexpr std::array<uint64_t,Q> opposite_index = {
+		0,2,1,
+		6,8,7,3,5,4,
+		18,20,19,24,26,25,21,23,22,9,11,10,15,17,16,12,14,13
+	};
+
+	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()};
+	}
+	*/
+};
+ 
+}
+}
+
+namespace saw {
+template<typename T, typename Desc, uint64_t S, uint64_t D, uint64_t Q>
+struct meta_schema<kel::lbm::sch::Cell<T,Desc,S,D,Q>> {
+	using MetaSchema = schema::Void;
+	using Schema = kel::lbm::sch::Cell<T,Desc,S,D,Q>;
+};
+
+template<typename Desc, typename CellT>
+struct meta_schema<kel::lbm::sch::CellField<Desc, CellT>> {
+	using MetaSchema = schema::FixedArray<schema::UInt64,Desc::D>;
+	using Schema = kel::lbm::sch::CellField<Desc, CellT>;
+};
+
+template<typename Desc, typename... CellFieldsT>
+struct meta_schema<kel::lbm::sch::CellFieldStruct<Desc,schema::Struct<CellFieldsT...>>> {
+	using MetaSchema = schema::FixedArray<schema::UInt64,Desc::D>;
+	using Schema = kel::lbm::sch::CellFieldStruct<Desc,schema::Struct<CellFieldsT...>>;
+};
+
+template<typename Sch, typename Desc, uint64_t S, uint64_t D, uint64_t Q, typename Encode>
+class data<kel::lbm::sch::Cell<Sch, Desc, S, D, Q>, Encode> final {
+public:
+	using Schema = kel::lbm::sch::Cell<Sch,Desc,S,D,Q>;
+	using MetaSchema = typename meta_schema<Schema>::MetaSchema;
+private:
+	data<schema::FixedArray<Sch, Schema::Size>, Encode> inner_;
+public:
+	data() = default;
+
+	data<Sch, Encode>& operator()(const data<schema::UInt64>& index){
+		return inner_.at(index);
+	}
+
+	const data<Sch, Encode>& operator()(const data<schema::UInt64>& index)const{
+		return inner_.at(index);
+	}
+
+	const data<kel::lbm::sch::Cell<Sch, Desc, S, D, Q>, Encode> copy() const {
+		return *this;
+	}
+};
+
+/*
+ * Create a cellfield
+ */
+template<typename Desc, typename CellT, typename Encode>
+class data<kel::lbm::sch::CellField<Desc, CellT>, Encode> final {
+public:
+	using Schema = kel::lbm::sch::CellField<Desc,CellT>;
+	using MetaSchema = typename meta_schema<Schema>::MetaSchema;
+private:
+	data<schema::Array<CellT,Desc::D>, Encode> inner_;
+public:
+	data() = default;
+	data(const data<MetaSchema,Encode>& inner_meta__):
+		inner_{inner_meta__}
+	{}
+
+	const data<MetaSchema, Encode> meta() const {
+		return inner_.dims();
+	}
+
+	template<uint64_t i>
+	data<schema::UInt64,Encode> get_dim_size() const {
+		static_assert(i < Desc::D, "Not enough dimensions");
+		return inner_.template get_dim_size<i>();
+	}
+
+	const data<CellT>& operator()(const data<schema::FixedArray<schema::UInt64, Desc::D>, Encode>& index)const{
+		return inner_.at(index);
+	}
+
+	data<CellT>& operator()(const data<schema::FixedArray<schema::UInt64, Desc::D>, Encode>& index){
+		return inner_.at(index);
+	}
+
+	const data<CellT>& at(const data<schema::FixedArray<schema::UInt64, Desc::D>, Encode>& index)const{
+		return inner_.at(index);
+	}
+
+	data<CellT>& at(const data<schema::FixedArray<schema::UInt64, Desc::D>, Encode>& index){
+		return inner_.at(index);
+	}
+
+	data<schema::UInt64,Encode> internal_size() const {
+		return inner_.internal_size();
+	}
+
+	data<CellT,Encode>* internal_data() {
+		return inner_.internal_data();
+	}
+};
+
+/**
+ * Is basically a struct, but additionally has members for meta() calls. It technically is a Field of a struct, but organized through a struct of fields.
+ */
+template<typename Desc, typename... CellFieldsT, typename Encode>
+class data<kel::lbm::sch::CellFieldStruct<Desc, schema::Struct<CellFieldsT...>>, Encode> final {
+public:
+	using Schema = kel::lbm::sch::CellFieldStruct<Desc,schema::Struct<CellFieldsT...>>;
+	/// @TODO Add MetaSchema to Schema
+	using MetaSchema = typename meta_schema<Schema>::MetaSchema;
+private:
+	static_assert(sizeof...(CellFieldsT) > 0u, "");
+	data<schema::Struct<CellFieldsT...>, Encode> inner_;
+
+	template<uint64_t i>
+	saw::error_or<void> helper_constructor(const data<schema::FixedArray<schema::UInt64,Desc::D>>& grid_size){
+		using MemT = saw::parameter_pack_type<i,CellFieldsT...>::type;
+		{
+			inner_.template get<MemT::KeyLiteral>() = {grid_size};
+		}
+		if constexpr (sizeof...(CellFieldsT) > (i+1u)){
+			return helper_constructor<i+1u>(grid_size);
+		}
+		return saw::make_void();
+	}
+public:
+	data() = delete;
+
+	data(const data<schema::FixedArray<schema::UInt64,Desc::D>>& grid_size__){
+		auto eov = helper_constructor<0u>(grid_size__);
+		(void)eov;
+	}
+
+	const data<MetaSchema, Encode> meta() const {
+		using MemT = saw::parameter_pack_type<0u,CellFieldsT...>::type;
+		return inner_.template get<MemT::KeyLiteral>().meta();
+	}
+
+	template<saw::string_literal Key>
+	auto& get() {
+		return inner_.template get<Key>();
+	}
+
+	template<saw::string_literal Key>
+	const auto& get() const {
+		return inner_.template get<Key>();
+	}
+};
+
+
+}
-- 
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