ParticleEventData
DynNewtonian::randomGaussianEvent(Particle& part, const double& sqrtT,
const size_t dimensions) const
{
#ifdef DYNAMO_DEBUG
if (dimensions > NDIM)
M_throw() << "Number of dimensions passed larger than NDIM!";
#endif
//See http://mathworld.wolfram.com/SpherePointPicking.html
if (hasOrientationData())
M_throw() << "Need to implement thermostating of the rotational degrees"
" of freedom";
//Ensure the particle is free streamed first
updateParticle(part);
//Collect the precoll data
ParticleEventData tmpDat(part, *Sim->species[part], GAUSSIAN);
double mass = Sim->species[tmpDat.getSpeciesID()]->getMass(part.getID());
double factor = sqrtT / std::sqrt(mass);
//Assign the new velocities
for (size_t iDim = 0; iDim < dimensions; iDim++)
part.getVelocity()[iDim] = Sim->normal_sampler() * factor;
tmpDat.setDeltaKE(0.5 * mass * (part.getVelocity().nrm2() - tmpDat.getOldVel().nrm2()));
return tmpDat;
}
ParticleEventData
DynNewtonian::runAndersenWallCollision(Particle& part, const Vector & vNorm, const double& sqrtT, const double) const
{
updateParticle(part);
if (hasOrientationData())
M_throw() << "Need to implement thermostating of the rotational degrees"
" of freedom";
//This gives a completely new random unit vector with a properly
//distributed Normal component. See Granular Simulation Book
ParticleEventData tmpDat(part, *Sim->species[part], WALL);
double mass = Sim->species[tmpDat.getSpeciesID()]->getMass(part.getID());
for (size_t iDim = 0; iDim < NDIM; iDim++)
part.getVelocity()[iDim] = Sim->normal_sampler() * sqrtT / std::sqrt(mass);
part.getVelocity()
//This first line adds a component in the direction of the normal
+= vNorm * (sqrtT * sqrt(-2.0*log(1.0-Sim->uniform_sampler()) / mass)
//This removes the original normal component
-(part.getVelocity() | vNorm));
tmpDat.setDeltaKE(0.5 * mass * (part.getVelocity().nrm2() - tmpDat.getOldVel().nrm2()));
return tmpDat;
}
ParticleEventData
DynCompression::runAndersenWallCollision(Particle& part, const Vector & vNorm, const double& sqrtT, const double d) const
{
updateParticle(part);
if (hasOrientationData())
M_throw() << "Need to implement thermostating of the rotational degrees"
" of freedom";
//This gives a completely new random unit vector with a properly
//distributed Normal component. See Granular Simulation Book
ParticleEventData tmpDat(part, *Sim->species[part], WALL);
double mass = Sim->species[tmpDat.getSpeciesID()]->getMass(part.getID());
std::normal_distribution<> normal_dist;
std::uniform_real_distribution<> uniform_dist;
for (size_t iDim = 0; iDim < NDIM; iDim++)
part.getVelocity()[iDim] = normal_dist(Sim->ranGenerator) * sqrtT / std::sqrt(mass);
part.getVelocity()
//This first line adds a component in the direction of the normal
+= vNorm * (sqrtT * sqrt(-2.0*log(1.0 - uniform_dist(Sim->ranGenerator)) / mass)
//This removes the original normal component
-(part.getVelocity() | vNorm)
//This adds on the velocity of the wall
+ d * growthRate)
;
return tmpDat;
}
