TruncatedGreenParticleInteraction.h

//
// Class TruncatedGreenParticleInteraction
//   This class implements the short range interaction part of the green function splitting obtained
//   by taking the gradient of [forceConstant * (1 - erf(alpha * r)) / r]. The long range part is
//   handled by FFTTruncatedGreenPeriodicSolver.
//
//   It assumes that ParticleContainer implements a function forAllPairs() to iterate over all
//   relevant particle pairs.
//
 
#ifndef IPPL_TRUNCATEDGREEN_SHORTRANGE_H
#define IPPL_TRUNCATEDGREEN_SHORTRANGE_H
 
#include "ParticleInteractionBase.h"
 
namespace ippl {
    template <typename ParticleContainer, typename VectorAttribute, typename ScalarAttribute>
    class TruncatedGreenParticleInteraction : public ParticleInteractionBase<ParticleContainer> {
    public:
        using Base            = ParticleInteractionBase<ParticleContainer>;
        using Vector_t        = typename VectorAttribute::value_type;
        using Scalar_t        = typename ScalarAttribute::value_type;
        using execution_space = typename VectorAttribute::execution_space;
        static_assert(std::is_same_v<execution_space, typename ScalarAttribute::execution_space>);
 
    public:
        TruncatedGreenParticleInteraction(const ParticleContainer& pc, VectorAttribute& F,
                                          const VectorAttribute& R, const ScalarAttribute& QM,
                                          const ParameterList& params)
            : Base(pc, params)
            , Field_m(F)
            , R_m(R)
            , QM_m(QM) {}
 
        ~TruncatedGreenParticleInteraction() override = default;
 
        void solve() override;
 
    private:
        KOKKOS_INLINE_FUNCTION static constexpr Vector_t fieldFromPair(const Vector_t& dist,
                                                                       Scalar_t r2, Scalar_t alpha,
                                                                       Scalar_t forceConstant,
                                                                       Scalar_t qm);
 
        VectorAttribute& Field_m;
        const VectorAttribute& R_m;
        const ScalarAttribute& QM_m;
    };
}  // namespace ippl
 
#include "TruncatedGreenParticleInteraction.hpp"
 
#endif  // IPPL_TRUNCATEDGREEN_SHORTRANGE_H