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authorClaudius "keldu" Holeksa <mail@keldu.de>2026-07-05 15:59:23 +0200
committerClaudius "keldu" Holeksa <mail@keldu.de>2026-07-05 15:59:23 +0200
commitc0549d71b2109f10c1238db8b22362e7826ba61b (patch)
tree16cd5264fcc3afe912e1b1b67738c8940d6d1177 /modules/core/c++/collision.hpp
parent9a3147bc79caf3c0fb1a9cdee29d156b5ff092c7 (diff)
downloadlibs-lbm-c0549d71b2109f10c1238db8b22362e7826ba61b.tar.gz
Just rename from lib to modules
Diffstat (limited to 'modules/core/c++/collision.hpp')
-rw-r--r--modules/core/c++/collision.hpp201
1 files changed, 201 insertions, 0 deletions
diff --git a/modules/core/c++/collision.hpp b/modules/core/c++/collision.hpp
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+++ b/modules/core/c++/collision.hpp
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+#pragma once
+
+#include "macroscopic.hpp"
+#include "component.hpp"
+#include "equilibrium.hpp"
+#include "chunk.hpp"
+
+namespace kel {
+namespace lbm {
+namespace cmpt {
+struct BGK {};
+struct BGKGuo {};
+}
+
+/**
+ * Standard BGK collision operator for LBM
+ */
+template<typename T, typename Descriptor, typename Encode>
+class component<T, Descriptor, cmpt::BGK, Encode> {
+private:
+ saw::data<T> relaxation_;
+ saw::data<T> frequency_;
+public:
+ component(typename saw::native_data_type<T>::type relaxation__):
+ relaxation_{{relaxation__}},
+ frequency_{saw::data<T>{1} / relaxation_}
+ {}
+
+ component(const saw::data<T>& relaxation__):
+ relaxation_{relaxation__},
+ frequency_{saw::data<T>{1} / relaxation_}
+ {}
+
+ using Component = cmpt::BGK;
+
+ /**
+ * Thoughts regarding automating order setup
+ */
+ using access = cmpt::access_tuple<
+ cmpt::access<"dfs", 1, true, true, true>
+ >;
+
+ /**
+ * Thoughts regarding automating order setup
+ */
+ static constexpr saw::string_literal name = "collision";
+ static constexpr saw::string_literal after = "";
+ static constexpr saw::string_literal before = "streaming";
+
+ /**
+ * Raw setup
+ */
+ template<typename CellFieldSchema>
+ void apply(const saw::data<CellFieldSchema, Encode>& field, saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> index, saw::data<sch::UInt64> time_step) const {
+ bool is_even = ((time_step.get() % 2) == 0);
+
+ // auto& dfs_f = (is_even) ? field.template get<"dfs">() : field.template get<"dfs_old">();
+ auto& dfs_old_f = (is_even) ? field.template get<"dfs_old">() : field.template get<"dfs">();
+
+ saw::data<sch::Scalar<T>> rho;
+ saw::data<sch::Vector<T,Descriptor::D>> vel;
+ compute_rho_u<T,Descriptor>(dfs_old_f.at(index),rho,vel);
+ auto eq = equilibrium<T,Descriptor>(rho,vel);
+
+ for(uint64_t i = 0u; i < Descriptor::Q; ++i){
+ 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}));
+ }
+ }
+
+ 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 {
+ bool is_even = ((time_step.get() % 2) == 0);
+
+ // auto& dfs_f = (is_even) ? field.template get<"dfs">() : field.template get<"dfs_old">();
+ auto& dfs_old_f = (is_even) ? field.template get<"dfs_old">() : field.template get<"dfs">();
+
+ 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);
+
+ for(uint64_t i = 0u; i < Descriptor::Q; ++i){
+ 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}));
+ }
+ }
+};
+
+template<typename T, typename Descriptor, typename Encode>
+class component<T, Descriptor, cmpt::BGKGuo, Encode> {
+private:
+ typename saw::native_data_type<T>::type relaxation_;
+ saw::data<T> frequency_;
+ saw::data<sch::Vector<T,Descriptor::D>> global_force_;
+public:
+ component(typename saw::native_data_type<T>::type relaxation__):
+ relaxation_{relaxation__},
+ frequency_{typename saw::native_data_type<T>::type(1) / relaxation_},
+ global_force_{}
+ {}
+
+ component(
+ typename saw::native_data_type<T>::type relaxation__,
+ saw::data<sch::Vector<T,Descriptor::D>>& global_force__
+ ):
+ relaxation_{relaxation__},
+ frequency_{typename saw::native_data_type<T>::type(1) / relaxation_},
+ global_force_{global_force__}
+ {}
+
+ using Component = cmpt::BGKGuo;
+
+ using access = cmpt::access_tuple<
+ cmpt::access<"dfs", 1, true, true, true>,
+ cmpt::access<"force", 0, true, false>
+ >;
+
+ /**
+ * Thoughts regarding automating order setup
+ */
+ static constexpr saw::string_literal name = "collision";
+ static constexpr saw::string_literal after = "";
+ static constexpr saw::string_literal before = "streaming";
+
+ 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 {
+ // 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">();
+
+ saw::data<sch::Scalar<T>>& rho = rho_f.at(index);
+
+ auto& force_f = macros.template get<"force">();
+ auto& force = force_f.at(index);
+
+ auto total_force = force + global_force_;
+
+ saw::data<sch::Scalar<T>> half;
+ half.at({}).set(0.5);
+ auto& vel = vel_f.at(index);
+ vel = vel + total_force * ( half / rho );
+
+ compute_rho_u<T,Descriptor>(dfs_old_f.at(index),rho,vel);
+ auto eq = equilibrium<T,Descriptor>(rho,vel);
+
+ using dfi = df_info<T,Descriptor>;
+
+
+ saw::data<sch::Scalar<T>> dfi_inv_cs2;
+ dfi_inv_cs2.at({}).set(dfi::inv_cs2);
+
+
+ // auto vel = vel_f.at(index);
+
+ for(uint64_t i = 0u; i < Descriptor::Q; ++i){
+ // saw::data<T> ci_min_u{0};
+ saw::data<sch::Vector<T,Descriptor::D>> ci;
+ for(uint64_t d = 0u; d < Descriptor::D; ++d){
+ ci.at({{d}}).set(static_cast<typename saw::native_data_type<T>::type>(dfi::directions[i][d]));
+ }
+ auto ci_dot_u = saw::math::dot(ci,vel);
+
+ // saw::data<sch::Vector<T,Descriptor::D>> F_i;
+ // F_i = f * ((c_i - u) * ics2 + <c_i,u> * c_i * ics2 * ics2) * w_i;
+ saw::data<sch::Scalar<T>> w;
+ w.at({}).set(dfi::weights[i]);
+
+ /*
+ saw::data<sch::Scalar<T>> F_i_sum;
+ for(uint64_t d = 0u; d < Descriptor::D; ++d){
+ saw::data<sch::Scalar<T>> F_i_d;
+ F_i_d.at({}) = F_i.at({{d}});
+ F_i_sum = F_i_sum + F_i_d;
+ }
+ */
+ auto term1 = (ci-vel) * dfi_inv_cs2;
+ auto term2 = ci * (ci_dot_u * dfi_inv_cs2 * dfi_inv_cs2);
+
+ auto force_projection = saw::math::dot(term1 + term2, total_force);
+
+ auto F_i = w * force_projection;
+
+ dfs.at({i}) = dfs.at({i})
+ + frequency_
+ * (eq.at(i) - dfs.at({i}) )
+ + F_i.at({})
+ * (saw::data<T>{1} - saw::data<T>{0.5f} * frequency_);
+ }
+ }
+};
+}
+}