void SBGaussian::SBGaussianImpl::shoot(PhotonArray& photons, UniformDeviate ud) const
{
const int N = photons.size();
dbg<<"Gaussian shoot: N = "<<N<<std::endl;
dbg<<"Target flux = "<<getFlux()<<std::endl;
double fluxPerPhoton = _flux/N;
for (int i=0; i<N; i++) {
// First get a point uniformly distributed on unit circle
#ifdef USE_COS_SIN
double theta = 2.*M_PI*ud();
double rsq = ud(); // cumulative dist function P(<r) = r^2 for unit circle
double sint,cost;
math::sincos(theta, sint, cost);
// Then map radius to the desired Gaussian with analytic transformation
double rFactor = _sigma * std::sqrt( -2. * std::log(rsq));
photons.setPhoton(i, rFactor*cost, rFactor*sint, fluxPerPhoton);
#else
double xu, yu, rsq;
do {
xu = 2.*ud()-1.;
yu = 2.*ud()-1.;
rsq = xu*xu+yu*yu;
} while (rsq>=1. || rsq==0.);
// Then map radius to the desired Gaussian with analytic transformation
double rFactor = _sigma * std::sqrt( -2. * std::log(rsq) / rsq);
photons.setPhoton(i, rFactor*xu, rFactor*yu, fluxPerPhoton);
#endif
}
dbg<<"Gaussian Realized flux = "<<photons.getTotalFlux()<<std::endl;
}
void SBAutoConvolve::SBAutoConvolveImpl::shoot(PhotonArray& photons, UniformDeviate ud) const
{
const int N = photons.size();
dbg<<"AutoConvolve shoot: N = "<<N<<std::endl;
dbg<<"Target flux = "<<getFlux()<<std::endl;
_adaptee.shoot(photons, ud);
PhotonArray temp(N);
_adaptee.shoot(temp, ud);
photons.convolve(temp, ud);
dbg<<"AutoConvolve Realized flux = "<<photons.getTotalFlux()<<std::endl;
}
void SBAutoCorrelate::SBAutoCorrelateImpl::shoot(PhotonArray& photons, UniformDeviate ud) const
{
const int N = photons.size();
dbg<<"AutoCorrelate shoot: N = "<<N<<std::endl;
dbg<<"Target flux = "<<getFlux()<<std::endl;
_adaptee.shoot(photons, ud);
PhotonArray temp(N);
_adaptee.shoot(temp, ud);
// Flip sign of (x,y) in one of the results
temp.scaleXY(-1.);
photons.convolve(temp, ud);
dbg<<"AutoCorrelate Realized flux = "<<photons.getTotalFlux()<<std::endl;
}
void SBConvolve::SBConvolveImpl::shoot(PhotonArray& photons, UniformDeviate ud) const
{
const int N = photons.size();
dbg<<"Convolve shoot: N = "<<N<<std::endl;
dbg<<"Target flux = "<<getFlux()<<std::endl;
std::list<SBProfile>::const_iterator pptr = _plist.begin();
if (pptr==_plist.end())
throw SBError("Cannot shoot() for empty SBConvolve");
pptr->shoot(photons, ud);
// It may be necessary to shuffle when convolving because we do
// do not have a gaurantee that the convolvee's photons are
// uncorrelated, e.g. they might both have their negative ones
// at the end.
// However, this decision is now made by the convolve method.
for (++pptr; pptr != _plist.end(); ++pptr) {
PhotonArray temp(N);
pptr->shoot(temp, ud);
photons.convolve(temp, ud);
}
dbg<<"Convolve Realized flux = "<<photons.getTotalFlux()<<std::endl;
}