 |
ESPResSo
Extensible Simulation Package for Research on Soft Matter Systems
|
|
ESPResSo
Extensible Simulation Package for Research on Soft Matter Systems
|
Own-the-loop specialization of the non-bonded pair kernel. More...
#include <forces_cabana.hpp>
Collaboration diagram for SpecializedForcesKernel< HasCoulomb >:Public Member Functions | |
| ESPRESSO_ATTR_ALWAYS_INLINE void | operator() (std::size_t const i) const |
Public Attributes | |
| InteractionsNonBonded const & | nonbonded_ias |
| CellStructure::AoSoA_pack const & | aosoa |
| CellStructure::ScatterForce | local_force |
| Kokkos::View< int const *, Kokkos::HostSpace > | counts |
| Kokkos::View< int const **, Kokkos::LayoutRight, Kokkos::HostSpace > | neighbors |
| CuboidMinimumImage | minimum_image |
| double | system_max_cutoff_sq |
| Coulomb::ShortRangeForceKernel::kernel_type const * | coulomb_kernel |
| CoulombP3M const * | p3m |
Static Public Attributes | |
| static constexpr int | tile_size = 64 |
Own-the-loop specialization of the non-bonded pair kernel.
Handles the common case of a cuboid box with only central radial pair forces active, optionally with real-space electrostatics (HasCoulomb). The dispatch in forces.cpp selects it only when no torque-producing, asymmetric, thermostat or exclusion interaction is active (no dipoles, ELC, DPD, NPT virial, exclusions, Thole or Gay-Berne, no Lees-Edwards), and falls back to ForcesKernel otherwise.
Unlike ForcesKernel (invoked once per pair by Cabana::neighbor_parallel_for), this owns the Verlet-list loop and runs once per particle. That lets it hoist the per-particle position, type and charge, capture the cuboid box parameters by value, and obtain the ScatterView accessor once per particle instead of once per pair – the per-pair access() is an omp_get_thread_num call that dominates the LJ pair cost. It also accumulates the i-side force in a local register over all of particle i's neighbors and updates the ScatterView once per particle instead of once per pair; the j-side write stays per-pair (each neighbor j is distinct). This removes the per-pair i-side accessor update at the cost of changing the i-side summation order (a single register sum added once, rather than incremental scatter adds), so the result matches ForcesKernel to floating-point round-off rather than bitwise. if constexpr (HasCoulomb) compiles the electrostatics path in or out entirely.
The neighbors are processed in fixed-size tiles, each in three passes: a scalar gather of the neighbor positions into SoA scratch, a vectorized minimum-image pass (CuboidMinimumImage::batch_vector_dist2) that folds the whole tile at once and squares the distances, and a scalar pass that runs the short-range force only for the pairs whose squared distance passes the cutoff gate. The vectorized pass yields the same per-pair fold vector and squared distance as the scalar path, so identity is preserved.
Definition at line 420 of file forces_cabana.hpp.
|
inline |
Definition at line 438 of file forces_cabana.hpp.
References SpecializedForcesKernel< HasCoulomb >::aosoa, CuboidMinimumImage::batch_vector_dist2(), calc_central_radial_force(), CellStructure::AoSoA_pack::charge, SpecializedForcesKernel< HasCoulomb >::coulomb_kernel, coulomb_pair_force(), SpecializedForcesKernel< HasCoulomb >::counts, InteractionsNonBonded::get_ia_param(), SpecializedForcesKernel< HasCoulomb >::local_force, SpecializedForcesKernel< HasCoulomb >::minimum_image, SpecializedForcesKernel< HasCoulomb >::neighbors, SpecializedForcesKernel< HasCoulomb >::nonbonded_ias, SpecializedForcesKernel< HasCoulomb >::p3m, CellStructure::AoSoA_pack::position, stream, SpecializedForcesKernel< HasCoulomb >::system_max_cutoff_sq, SpecializedForcesKernel< HasCoulomb >::tile_size, and CellStructure::AoSoA_pack::type.
| CellStructure::AoSoA_pack const& SpecializedForcesKernel< HasCoulomb >::aosoa |
Definition at line 424 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| Coulomb::ShortRangeForceKernel::kernel_type const* SpecializedForcesKernel< HasCoulomb >::coulomb_kernel |
Definition at line 431 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| Kokkos::View<int const *, Kokkos::HostSpace> SpecializedForcesKernel< HasCoulomb >::counts |
Definition at line 426 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| CellStructure::ScatterForce SpecializedForcesKernel< HasCoulomb >::local_force |
Definition at line 425 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| CuboidMinimumImage SpecializedForcesKernel< HasCoulomb >::minimum_image |
Definition at line 428 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| Kokkos::View<int const **, Kokkos::LayoutRight, Kokkos::HostSpace> SpecializedForcesKernel< HasCoulomb >::neighbors |
Definition at line 427 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| InteractionsNonBonded const& SpecializedForcesKernel< HasCoulomb >::nonbonded_ias |
Definition at line 423 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| CoulombP3M const* SpecializedForcesKernel< HasCoulomb >::p3m |
Definition at line 433 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
| double SpecializedForcesKernel< HasCoulomb >::system_max_cutoff_sq |
Definition at line 429 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
|
staticconstexpr |
Definition at line 421 of file forces_cabana.hpp.
Referenced by SpecializedForcesKernel< HasCoulomb >::operator()().
1.9.8