influence_function.hpp File Reference

#include "p3m/common.hpp"
#include "p3m/for_each_3d.hpp"
#include "p3m/math.hpp"
#include <utils/Vector.hpp>
#include <utils/index.hpp>
#include <utils/math/int_pow.hpp>
#include <utils/math/sqr.hpp>
#include <cmath>
#include <cstddef>
#include <functional>
#include <numbers>
#include <utility>
#include <vector>

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Functions
template<std::size_t S, std::size_t m>
double	G_opt (int cao, double alpha, Utils::Vector3d const &k, Utils::Vector3d const &h)
	Hockney/Eastwood/Ballenegger optimal influence function.
template<typename FloatType , std::size_t S, std::size_t m = 0>
std::vector< FloatType >	grid_influence_function (P3MParameters const &params, Utils::Vector3i const &n_start, Utils::Vector3i const &n_stop, int const KX, int const KY, int const KZ, Utils::Vector3d const &inv_box_l)
	Map influence function over a grid.

Function Documentation

G_opt()

template<std::size_t S, std::size_t m>

double G_opt	(	int	cao,
		double	alpha,
		Utils::Vector3d const &	k,
		Utils::Vector3d const &	h
	)

Hockney/Eastwood/Ballenegger optimal influence function.

This implements Eq. 30 of [9], which can be used for monopole and dipole P3M by choosing the appropriate S factor.

Template Parameters

S	Order of the differential operator, e.g. 0 for potential, 1 for electric field, ...
m	Number of aliasing terms to take into account.

Parameters

cao	Charge assignment order.
alpha	Ewald splitting parameter.
k	k-vector to evaluate the function for.
h	Grid spacing.

Definition at line 54 of file influence_function.hpp.

References Utils::Vector< T, N >::broadcast(), for_each_3d(), Utils::Vector< T, N >::norm2(), Utils::product(), math::sinc(), and Utils::sqr().

grid_influence_function()

template<typename FloatType , std::size_t S, std::size_t m = 0>

std::vector< FloatType > grid_influence_function	(	P3MParameters const &	params,
		Utils::Vector3i const &	n_start,
		Utils::Vector3i const &	n_stop,
		int const	KX,
		int const	KY,
		int const	KZ,
		Utils::Vector3d const &	inv_box_l
	)

Map influence function over a grid.

This evaluates the optimal influence function G_opt over a regular grid of k vectors, and returns the values as a vector.

Template Parameters

S	Order of the differential operator, e.g. 0 for potential, 1 for electric field...
m	Number of aliasing terms to take into account.

Parameters

params	P3M parameters.
n_start	Lower left corner of the grid.
n_stop	Upper right corner of the grid.
KX	k-space x-axis index.
KY	k-space y-axis index.
KZ	k-space z-axis index.
inv_box_l	Inverse box length.

Returns

Values of G_opt at regular grid points.

Definition at line 114 of file influence_function.hpp.

References for_each_3d(), params, and Utils::product().