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/////////////////////////////////////////////////////////////
// //
// Copyright (c) 2003-2014 by The University of Queensland //
// Centre for Geoscience Computing //
// http://earth.uq.edu.au/centre-geoscience-computing //
// //
// Primary Business: Brisbane, Queensland, Australia //
// Licensed under the Open Software License version 3.0 //
// http://www.apache.org/licenses/LICENSE-2.0 //
// //
/////////////////////////////////////////////////////////////
#ifndef __ROT_DAMPING_HPP
#define __ROT_DAMPING_HPP
template <class T>
double CRotDamping<T>::s_limit2=1e-12; // default error limit : 1e-6
template <class T>
int CRotDamping<T>::s_flops = 0;
/*!
Construct a rotational damping "interaction" for a particle
\param P the particle
\param param pointer to the parameters
*/
template <class T>
CRotDamping<T>::CRotDamping(T* P,CDampingIGP* param)
{
m_p=P;
m_vref=param->getVRef();
m_visc=param->getVisc();
m_dt=param->getTimeStep();
m_maxiter=param->getMaxIter();
}
/*!
destructor
*/
template <class T>
CRotDamping<T>::~CRotDamping()
{
}
template <class T>
void CRotDamping<T>::setTimeStepSize(double dt)
{
m_dt = dt;
}
/*!
Calculate the damping force.
25*count+8 flops
*/
template <class T>
void CRotDamping<T>::calcForces()
{
m_E_diss=0.0;// zero dissipated energy
Vec3 v=m_p->getAngVel();
Vec3 v_rel=Vec3(0.0,0.0,0.0);
Vec3 frc=m_p->getMoment();
double s=1.0/m_p->getInertRot();
double in=m_p->getInertRot();
double mass=m_p->getMass();
double error=1.0;
int count=0;
while((error*error>s_limit2) & (count<m_maxiter)){ // 1 flop
count++;
Vec3 v_old=v_rel;
v_rel=v-m_vref+s*m_dt*(frc-v_rel*m_visc*in); // 16 flops
error=(v_rel-v_old).norm2(); // 8 flops
}
if(count>=m_maxiter){
//console.Warning() << "damping diverges for particle " << m_p->getID() << "error= " << error << "\n";
v_rel=Vec3(0.0,0.0,0.0);
}
m_force=-1.0*m_visc*v_rel*mass;
m_p->applyMoment(-1.0*m_visc*v_rel*in); // 3 flops
m_E_diss=m_visc*v_rel*v*m_dt; // wrong
}
/*!
Get the particle member function which returns a scalar field of a given name.
\param name the name of the field
*/
template <class T>
typename CRotDamping<T>::ScalarFieldFunction CRotDamping<T>::getScalarFieldFunction(const string& name)
{
typename CRotDamping<T>::ScalarFieldFunction sf;
if(name=="dissipated_energy"){
sf=&CRotDamping<T>::getDissipatedEnergy;
} else {
sf=NULL;
cerr << "ERROR - invalid name for interaction scalar access function" << endl;
}
return sf;
}
/*!
Get the particle member function which returns a checked scalar field of a given name.
\param name the name of the field
*/
template <class T>
typename CRotDamping<T>::CheckedScalarFieldFunction CRotDamping<T>::getCheckedScalarFieldFunction(const string& name)
{
typename CRotDamping<T>::CheckedScalarFieldFunction sf;
sf=NULL;
cerr << "ERROR - invalid name for interaction scalar access function" << endl;
return sf;
}
/*!
Get the particle member function which returns a vector field of a given name.
\param name the name of the field
*/
template <class T>
typename CRotDamping<T>::VectorFieldFunction CRotDamping<T>::getVectorFieldFunction(const string& name)
{
typename CRotDamping<T>::VectorFieldFunction vf;
if (name=="force"){
vf=&CRotDamping<T>::getForce;
} else {
vf=NULL;
cerr << "ERROR - invalid name for interaction vector access function" << endl;
}
return vf;
}
/*!
return the amount of energy dissipated during the last time step
*/
template <class T>
double CRotDamping<T>::getDissipatedEnergy() const
{
return m_E_diss;
}
template <class T>
Vec3 CRotDamping<T>::getForce() const
{
return m_force;
}
/*!
check if any of the particles in the interaction fits tag & mask
\param tag the tag
\param mask the mask
*/
template <class T>
bool CRotDamping<T>::hasTag(int tag,int mask) const
{
int tag1=m_p->getTag();
return ((tag1 & mask)==(tag & mask));
}
/*!
return a vector of all particle IDs
*/
template <class T>
vector<int> CRotDamping<T>::getAllID() const
{
vector<int> res;
res.push_back(m_p->getID());
return res;
}
#endif // __ROT_DAMPING_HPP
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