Class to calculate the smoothed Lennard-Jones force between particles. Implements the interface PairwiseForceSource. More...

#include <SmoothedLennardJonesForce.h>

Inheritance diagram for SmoothedLennardJonesForce:

Collaboration diagram for SmoothedLennardJonesForce:

Public Member Functions
	SmoothedLennardJonesForce (double r_c, double r_l)
	Construct a new SmoothedLennardJonesForce object. More...

std::array< double, 3UL >	calculateForce (const Particle &p, const Particle &q) const override
	Calculates the smoothed Lennard-Jones forces between two particles. More...

	operator std::string () const override
	Returns "SmoothedLennardJones" as the name of the force. More...

Public Member Functions inherited from PairwiseForceSource
virtual	~PairwiseForceSource ()=default
	Virtual destructor for correct cleanup of derived classes. More...

Private Attributes
double	r_c
	the radius after which the force is 0 More...

double	r_l
	the radius whithin the normal Lennard-Jones force is applied. Between r_l and r_c the force is smoothed out More...

Detailed Description

Class to calculate the smoothed Lennard-Jones force between particles. Implements the interface PairwiseForceSource.

This class behaves similar like the normal Lennard-Jones force, but it is smoothed out between the smoothing radius r_l and the cutoff radius r_c.

Implementation of the force calculation to simulate a smooth Lennard-Jones forces between particles.

Definition at line 13 of file SmoothedLennardJonesForce.h.

Constructor & Destructor Documentation

◆ SmoothedLennardJonesForce()

SmoothedLennardJonesForce::SmoothedLennardJonesForce	(	double	r_c,
		double	r_l
	)

inline

Construct a new SmoothedLennardJonesForce object.

Parameters

r_c	cutoff radius
r_l	smoothing radius

Definition at line 21 of file SmoothedLennardJonesForce.h.

21 : r_c(r_c), r_l(r_l){};

SmoothedLennardJonesForce::r_c

double r_c

the radius after which the force is 0

Definition: SmoothedLennardJonesForce.h:43

SmoothedLennardJonesForce::r_l

double r_l

the radius whithin the normal Lennard-Jones force is applied. Between r_l and r_c the force is smooth...

Definition: SmoothedLennardJonesForce.h:48

Member Function Documentation

◆ calculateForce()

std::array< double, 3UL > SmoothedLennardJonesForce::calculateForce	(	const Particle &	p,
		const Particle &	q
	)		const

overridevirtual

Calculates the smoothed Lennard-Jones forces between two particles.

Parameters

p	Particle
q	Particle

Returns: smoothed Lennard-Jones force exerted by q on p

Calculates the Lennard-Jones force which q exerts on p

Implements PairwiseForceSource.

Definition at line 6 of file SmoothedLennardJonesForce.cpp.

                                                                                                           {
     const auto displacement = q.getX() - p.getX();
     const double dist = ArrayUtils::L2Norm(displacement);
  
     if (dist <= r_l) {
         static LennardJonesForce lennard_jones_force;
         return lennard_jones_force.calculateForce(p, q);
     } else if (dist <= r_c) {
         const double sigma = (p.getSigma() + q.getSigma()) / 2;
         const double epsilon = std::sqrt(p.getEpsilon() * q.getEpsilon());
  
         const double sigma_pow_6 = std::pow(sigma, 6);
         const double dist_pow_6 = std::pow(dist, 6);
  
         const auto f_smoothed_lennard_jones =
             (-24 * sigma_pow_6 * epsilon) / (std::pow(dist, 14) * std::pow(r_c - r_l, 3)) * (r_c - dist) *
             (r_c * r_c * (2 * sigma_pow_6 - dist_pow_6) + r_c * (3 * r_l - dist) * (dist_pow_6 - 2 * sigma_pow_6) +
              dist * (5 * r_l * sigma_pow_6 - 2 * r_l * dist_pow_6 - 3 * sigma_pow_6 * dist + std::pow(dist, 7))) *
             displacement;
  
         return f_smoothed_lennard_jones;
     } else {
         return {0, 0, 0};
     }
 };

◆ operator std::string()

SmoothedLennardJonesForce::operator std::string ( ) const

explicitoverridevirtual

Returns "SmoothedLennardJones" as the name of the force.

Implements PairwiseForceSource.

Definition at line 32 of file SmoothedLennardJonesForce.cpp.

32 { return "SmoothedLennardJones"; }

Member Data Documentation

◆ r_c

double SmoothedLennardJonesForce::r_c

private

the radius after which the force is 0

Definition at line 43 of file SmoothedLennardJonesForce.h.

◆ r_l

double SmoothedLennardJonesForce::r_l

private

the radius whithin the normal Lennard-Jones force is applied. Between r_l and r_c the force is smoothed out

Definition at line 48 of file SmoothedLennardJonesForce.h.

The documentation for this class was generated from the following files:

Public Member Functions

Private Attributes