From 51fb97c0fc981f5a1e08f83b12f9d0712c69ead3 Mon Sep 17 00:00:00 2001 From: "Claudius \"keldu\" Holeksa" Date: Mon, 23 Mar 2026 16:57:33 +0100 Subject: Fixed boundaries for D2Q9 Pressure Zou He --- lib/core/c++/boundary.hpp | 50 +++++++++++++++++++---------------------------- 1 file changed, 20 insertions(+), 30 deletions(-) diff --git a/lib/core/c++/boundary.hpp b/lib/core/c++/boundary.hpp index bb8eed9..ef468be 100644 --- a/lib/core/c++/boundary.hpp +++ b/lib/core/c++/boundary.hpp @@ -191,43 +191,33 @@ public: auto& dfs_old_f = (is_even) ? field.template get<"dfs_old">() : field.template get<"dfs">(); auto& dfs_old = dfs_old_f.at(index); - /** - * Sum all known DFs - */ - saw::data sum_df{0}; - for(saw::data k{0u}; k < saw::data{Descriptor::Q}; ++k){ - auto c_k = dfi::directions[k.get()]; - - if(c_k[0u]*known_dir <= 0){ - sum_df += dfs_old.at({k}); - } - } - - /** - * Get the sum of the unknown dfs and precalculate the direction - */ - auto sum_unknown_dfs = (rho_setting_ - sum_df); - auto unknown_dfs_dir = sum_unknown_dfs * saw::data{known_dir}; - for(saw::data k{0u}; k < saw::data{Descriptor::Q}; ++k){ - auto c_k = dfi::directions[k.get()]; - if(c_k[0u]*known_dir < 0){ - unknown_dfs_dir += dfs_old.at({k}) * c_k[0u]; + auto rho_vel_x = [&](){ + if constexpr (Dir) -> saw::data { + auto S = dfs_old.at({0u}) + + dfs_old.at({3u}) + dfs_old.at({4u}) + + (dfs_old.at({1u}) + dfs_old.at({5u}) + dfs_old.at({7u})) * 2u; + return rho_setting_ - S; } - } - - auto vel_x = unknown_dfs_dir / rho_setting_; + else if constexpr (not Dir) { + auto S = dfs_old.at({0u}) + + dfs_old.at({3u}) + dfs_old.at({4u}) + + (dfs_old.at({2u}) + dfs_old.at({6u}) + dfs_old.at({8u})) * 2u; + return S - rho_setting_; + } + return {}; + }(); static_assert(Descriptor::D == 2u and Descriptor::Q == 9u, "Some parts are hard coded sadly"); if constexpr (Dir) { - dfs_old.at({2u}) = dfs_old.at({1u}) + saw::data{2.0 / 3.0} * rho_setting_ * vel_x; - dfs_old.at({6u}) = dfs_old.at({5u}) + saw::data{1.0 / 6.0} * rho_setting_ * vel_x + saw::data{0.5} * (dfs_old.at({4u}) - dfs_old.at({3u})); - dfs_old.at({8u}) = dfs_old.at({7u}) + saw::data{1.0 / 6.0} * rho_setting_ * vel_x + saw::data{0.5} * (dfs_old.at({3u}) - dfs_old.at({4u})); + dfs_old.at({2u}) = dfs_old.at({1u}) + saw::data{2.0 / 3.0} * rho_vel_x; + dfs_old.at({6u}) = dfs_old.at({5u}) + saw::data{1.0 / 6.0} * rho_vel_x + saw::data{0.5} * (dfs_old.at({4u}) - dfs_old.at({3u})); + dfs_old.at({8u}) = dfs_old.at({7u}) + saw::data{1.0 / 6.0} * rho_vel_x + saw::data{0.5} * (dfs_old.at({3u}) - dfs_old.at({4u})); }else if constexpr (not Dir){ - dfs_old.at({1u}) = dfs_old.at({2u}) - saw::data{2.0 / 3.0} * rho_setting_ * vel_x; - dfs_old.at({5u}) = dfs_old.at({6u}) - saw::data{1.0 / 6.0} * rho_setting_ * vel_x + saw::data{0.5} * (dfs_old.at({3u}) - dfs_old.at({4u})); - dfs_old.at({7u}) = dfs_old.at({8u}) - saw::data{1.0 / 6.0} * rho_setting_ * vel_x + saw::data{0.5} * (dfs_old.at({4u}) - dfs_old.at({3u})); + dfs_old.at({1u}) = dfs_old.at({2u}) - saw::data{2.0 / 3.0} * rho_vel_x; + dfs_old.at({5u}) = dfs_old.at({6u}) - saw::data{1.0 / 6.0} * rho_vel_x + saw::data{0.5} * (dfs_old.at({3u}) - dfs_old.at({4u})); + dfs_old.at({7u}) = dfs_old.at({8u}) - saw::data{1.0 / 6.0} * rho_vel_x + saw::data{0.5} * (dfs_old.at({4u}) - dfs_old.at({3u})); } } }; -- cgit v1.2.3