common.hpp File Reference

Common functions for dipolar and charge P3M. More...

#include <config/config.hpp>
#include <utils/Vector.hpp>
#include <utils/index.hpp>
#include <algorithm>
#include <array>
#include <vector>
#include "LocalBox.hpp"
#include <Kokkos_Core.hpp>
#include <cstddef>
#include <optional>
#include <span>
#include <stdexcept>

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Classes
struct	P3MParameters
	Structure to hold P3M parameters and some dependent variables. More...
struct	P3MLocalMesh
	Properties of the local mesh and halo region. More...
struct	P3MFFTMesh< FloatType >
	Local mesh FFT buffers. More...
struct	TuningParameters
struct	P3MFFTConfig< RSpaceOrder, KSpaceOrder, UseR2C, R2CDir >

Enumerations
enum class	Arch { CPU , CUDA }
	P3M kernel architecture. More...

Functions
template<unsigned int r2c_dir>
void	influence_function_r2c (auto &g_function, auto const &global_size, auto const &local_size, auto const &local_origin)
	Adapt an influence function grid for real-to-complex FFTs.
std::array< std::vector< int >, 3 >	calc_p3m_mesh_shift (Utils::Vector3i const &mesh_size, bool zero_out_midpoint=false)
	Calculate indices that shift P3MParameters::mesh by mesh/2.

Variables
auto constexpr	P3M_EPSILON_METALLIC = 0.0
	This value indicates metallic boundary conditions.

Detailed Description

Common functions for dipolar and charge P3M.

We use here a P3M (Particle-Particle Particle-Mesh) method based on the Ewald summation. Details of the used method can be found in [23] and [11] [12]. The file p3m contains only the Particle-Mesh part.

Further reading: [19], [23], [11], [12], [13], [14], [10]

Definition in file p3m/common.hpp.

Enumeration Type Documentation

Arch

enum class Arch

strong

P3M kernel architecture.

Enumerator
CPU
CUDA

Definition at line 61 of file p3m/common.hpp.

Function Documentation

calc_p3m_mesh_shift()

std::array< std::vector< int >, 3 > calc_p3m_mesh_shift ( Utils::Vector3i const &  mesh_size, bool  zero_out_midpoint = false  )

inline

Calculate indices that shift P3MParameters::mesh by mesh/2.

For each mesh size \( n \) in mesh_size, create a sequence of integer values \( \left( 0, \ldots, \lfloor n/2 \rfloor, -\lfloor n/2 \rfloor, \ldots, -1\right) \) if zero_out_midpoint is false, otherwise \( \left( 0, \ldots, \lfloor n/2 - 1 \rfloor, 0, -\lfloor n/2 \rfloor, \ldots, -1\right) \).

Definition at line 311 of file p3m/common.hpp.

References stream.

Referenced by P3MStateCommon< FloatType, Architecture >::calc_differential_operator(), grid_influence_function(), grid_influence_function_dipolar(), and grid_influence_function_self_energy().

influence_function_r2c()

template<unsigned int r2c_dir>

void influence_function_r2c	(	auto &	g_function,
		auto const &	global_size,
		auto const &	local_size,
		auto const &	local_origin
	)

Adapt an influence function grid for real-to-complex FFTs.

Parameters

[in]	global_size	size of the global mesh grid
[in]	local_size	size of the local mesh grid
[in]	local_origin	offset of the local mesh grid
[in,out]	g_function	influence function grid to modify in-place

Template Parameters

r2c_dir

direction of the reduced dimension

Definition at line 278 of file p3m/common.hpp.

References Utils::Vector< T, N >::broadcast(), and stream.

Variable Documentation

P3M_EPSILON_METALLIC

auto constexpr P3M_EPSILON_METALLIC = 0.0

inlineconstexpr

This value indicates metallic boundary conditions.

Definition at line 47 of file p3m/common.hpp.

Referenced by CoulombP3MHeffte< FloatType, Architecture, FFTConfig >::adapt_epsilon_elc(), DipolarLayerCorrection::adapt_solver(), DipolarLayerCorrection::add_force_corrections(), DipolarLayerCorrection::energy_correction(), CoulombP3MHeffte< FloatType, Architecture, FFTConfig >::long_range_kernel(), AdaptSolver::operator()(), and CoulombP3M::sanity_checks_boxl().