void LocalBrownianMotionWalker::generate(size_t timepos) {
if (m_init) init();
size_t oldtimepos = translations.size();
if (timepos<oldtimepos) return; // don't generate anything if we already have it
CartesianCoor3D oldtranslation(0,0,0);
if (oldtimepos>0) {
oldtranslation = translations[oldtimepos-1];
}
for(size_t ti = oldtimepos; ti <= timepos; ++ti)
{
CartesianCoor3D newtrans;
while(true) {
double normran = (*p_mynormaldistribution)();
vector<double> sphereran = (*p_myspheredistribution)();
for(size_t i = 0; i < (m_sampling-1); ++i)
{
(*p_mynormaldistribution)();
(*p_myspheredistribution)();
}
double displacement = m_displace * normran;
newtrans = oldtranslation + displacement*CartesianCoor3D(sphereran[0],sphereran[1],sphereran[2]) ;
if (newtrans.length()>m_radius) continue; else break;
}
translations[ti] = newtrans;
oldtranslation = newtrans;
}
}
double ScatterFactors::compute_background(CartesianCoor3D q) {
double efactor_sum = 0;
double sf_sum=0;
double ql = q.length();
for(size_t i = 0; i < p_selection->size(); ++i)
{
size_t atomID = p_sample->atoms[(*p_selection)[i]];
double sf = Database::Inst()->sfactors.get(atomID,ql);
double k = m_kappas[(*p_selection)[i]];
double v = Database::Inst()->volumes.get(atomID);
double efactor = Database::Inst()->exclusionfactors.get(atomID,k*v,ql);
efactor_sum+=efactor;
sf_sum+=sf;
}
return sf_sum/efactor_sum;
}
void ScatterFactors::update(CartesianCoor3D q) {
double background_sl = Params::Inst()->scattering.background.factor;
for(size_t i = 0; i < p_selection->size(); ++i)
{
size_t atomID = p_sample->atoms[(*p_selection)[i]];
double ql = q.length();
double sf = Database::Inst()->sfactors.get(atomID,ql);
// calculate effective scattering length:
if (m_background) {
double k = m_kappas[(*p_selection)[i]];
double v = Database::Inst()->volumes.get(atomID);
double efactor = Database::Inst()->exclusionfactors.get(atomID,k*v,ql);
sf = sf - background_sl*efactor;
}
factors[i] = sf;
}
}
FixedMotionWalker::FixedMotionWalker(double displace,CartesianCoor3D direction) {
m_translate = displace*direction/direction.length();
}
LinearMotionWalker::LinearMotionWalker(double displace,long sampling, CartesianCoor3D direction) {
m_translate = displace*sampling*direction/direction.length();
}
OscillationMotionWalker::OscillationMotionWalker(double displace,double frequency,long sampling, CartesianCoor3D direction) {
m_translate = displace*direction/direction.length();
m_frequency = frequency;
m_sampling = sampling;
}