1 files changed, 59 insertions, 0 deletions
diff --git a/c++/boundary.hpp b/c++/boundary.hpp
new file mode 100644
index 0000000..77542c5
--- /dev/null
+++ b/c++/boundary.hpp
@@ -0,0 +1,59 @@
+#pragma once
+
+#include "component.hpp"
+#include "equilibrium.hpp"
+
+namespace kel {
+namespace lbm {
+namespace cmpt {
+struct BounceBack {};
+}
+
+template<typename T, typename Descriptor>
+class component<T, Descriptor, cmpt::BounceBack> {
+private:
+	typename saw::native_data_type<T>::type relaxation_;
+public:
+	component(typename saw::native_data_type<T>::type relaxation__):
+		relaxation_{relaxation__}
+	{}
+
+	using Component = cmpt::BounceBack;
+
+	/**
+	 * 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(saw::data<CellFieldSchema>& field, saw::data<sch::FixedArray<sch::UInt64,Descriptor::D>> index, uint64_t time_step){
+		bool is_even = ((time_step % 2) == 0);
+		auto& cell = field.at(index);
+
+		auto& dfs_old = is_even ? cell.template get<"dfs_old">() : cell.template get<"dfs">();
+		auto& dfs = (!is_even) ? cell.template get<"dfs_old">() : cell.template get<"dfs">();
+
+		using dfi = df_info<sch::T,Desc>;
+
+		// Technically use .copy()
+		auto df_cpy = dfs;
+
+		for(uint64_t i = 1u; i < Desc::Q; ++i){
+			dfs({i}) = df_cpy({dfi::opposite_index.at(i)});
+		}
+	}
+};
+}
+}