ESPResSo
Extensible Simulation Package for Research on Soft Matter Systems
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dpd.hpp File Reference

Routines to use DPD as thermostat or pair force [38]. More...

#include "config/config.hpp"
#include "BoxGeometry.hpp"
#include "Particle.hpp"
#include "thermostat.hpp"
#include <utils/Vector.hpp>
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Go to the source code of this file.

Namespaces

namespace  boost
 
namespace  boost::mpi
 

Functions

void dpd_init (double kT, double time_step)
 
Utils::Vector3d dpd_pair_force (Particle const &p1, Particle const &p2, DPDThermostat const &dpd, BoxGeometry const &box_geo, IA_parameters const &ia_params, Utils::Vector3d const &d, double dist, double dist2)
 
Utils::Vector9d dpd_stress (boost::mpi::communicator const &comm)
 Viscous stress tensor of the DPD interaction.
 

Detailed Description

Routines to use DPD as thermostat or pair force [38].

Implementation in dpd.cpp.

Definition in file dpd.hpp.

Function Documentation

◆ dpd_init()

void dpd_init ( double  kT,
double  time_step 
)

◆ dpd_pair_force()

Utils::Vector3d dpd_pair_force ( Particle const &  p1,
Particle const &  p2,
DPDThermostat const &  dpd,
BoxGeometry const &  box_geo,
IA_parameters const &  ia_params,
Utils::Vector3d const &  d,
double  dist,
double  dist2 
)

◆ dpd_stress()

Utils::Vector9d dpd_stress ( boost::mpi::communicator const &  comm)

Viscous stress tensor of the DPD interaction.

This calculates the total viscous stress contribution of the DPD interaction. It contains only the dissipative contributions of the interaction without noise. It's calculated as the sum over all pair virials as

\[ \sigma^{\nu\mu} = V^{-1}\sum_i \sum_{j < i} r_{i,j}^{\nu} (- \gamma_{i,j} v_{i,j})^{\mu} \]

where \(\gamma_{i,j}\) is the (in general tensor valued) DPD friction coefficient for particles i and j, \(v_{i,j}\), \(r_{i,j}\) are their relative velocity and distance and \(V\) is the box volume.

Returns
Stress tensor contribution.

Definition at line 174 of file dpd.cpp.

References System::System::box_geo, dpd_viscous_stress_local(), Utils::flatten(), and System::get_system().

Referenced by ScriptInterface::Analysis::Analysis::do_call_method(), and Observables::DPDStress::operator()().