SBGaussian::SBGaussianImpl::SBGaussianImpl(double sigma, double flux) :
_flux(flux), _sigma(sigma), _sigma_sq(sigma*sigma)
{
// For large k, we clip the result of kValue to 0.
// We do this when the correct answer is less than kvalue_accuracy.
// exp(-k^2*sigma^2/2) = kvalue_accuracy
_ksq_max = -2. * std::log(sbp::kvalue_accuracy) / _sigma_sq;
// For small k, we can use up to quartic in the taylor expansion to avoid the exp.
// This is acceptable when the next term is less than kvalue_accuracy.
// 1/48 (k^2 r0^2)^3 = kvalue_accuracy
_ksq_min = std::pow(sbp::kvalue_accuracy * 48., 1./3.) / _sigma_sq;
_norm = _flux / (_sigma_sq * 2. * M_PI);
dbg<<"Gaussian:\n";
dbg<<"_flux = "<<_flux<<std::endl;
dbg<<"_sigma = "<<_sigma<<std::endl;
dbg<<"_sigma_sq = "<<_sigma_sq<<std::endl;
dbg<<"_ksq_max = "<<_ksq_max<<std::endl;
dbg<<"_ksq_min = "<<_ksq_min<<std::endl;
dbg<<"_norm = "<<_norm<<std::endl;
dbg<<"maxK() = "<<maxK()<<std::endl;
dbg<<"stepK() = "<<stepK()<<std::endl;
}
SBGaussian::SBGaussianImpl::SBGaussianImpl(double sigma, double flux,
const GSParamsPtr& gsparams) :
SBProfileImpl(gsparams),
_flux(flux), _sigma(sigma), _sigma_sq(_sigma*_sigma),
_inv_sigma(1./_sigma), _inv_sigma_sq(_inv_sigma*_inv_sigma)
{
// For large k, we clip the result of kValue to 0.
// We do this when the correct answer is less than kvalue_accuracy.
// exp(-k^2*sigma^2/2) = kvalue_accuracy
_ksq_max = -2. * std::log(this->gsparams->kvalue_accuracy);
// For small k, we can use up to quartic in the taylor expansion to avoid the exp.
// This is acceptable when the next term is less than kvalue_accuracy.
// 1/48 (k^2 r0^2)^3 = kvalue_accuracy
_ksq_min = std::pow(this->gsparams->kvalue_accuracy * 48., 1./3.);
_norm = _flux * _inv_sigma_sq / (2. * M_PI);
dbg<<"Gaussian:\n";
dbg<<"_flux = "<<_flux<<std::endl;
dbg<<"_sigma = "<<_sigma<<std::endl;
dbg<<"_ksq_max = "<<_ksq_max<<std::endl;
dbg<<"_ksq_min = "<<_ksq_min<<std::endl;
dbg<<"_norm = "<<_norm<<std::endl;
dbg<<"maxK() = "<<maxK()<<std::endl;
dbg<<"stepK() = "<<stepK()<<std::endl;
}
SBExponential::SBExponentialImpl::SBExponentialImpl(
double r0, double flux, const GSParamsPtr& gsparams) :
SBProfileImpl(gsparams),
_flux(flux), _r0(r0), _r0_sq(_r0*_r0), _inv_r0(1./r0), _inv_r0_sq(_inv_r0*_inv_r0),
_info(cache.get(this->gsparams.duplicate()))
{
// For large k, we clip the result of kValue to 0.
// We do this when the correct answer is less than kvalue_accuracy.
// (1+k^2 r0^2)^-1.5 = kvalue_accuracy
_ksq_max = (std::pow(this->gsparams->kvalue_accuracy,-1./1.5)-1.);
// For small k, we can use up to quartic in the taylor expansion to avoid the sqrt.
// This is acceptable when the next term is less than kvalue_accuracy.
// 35/16 (k^2 r0^2)^3 = kvalue_accuracy
_ksq_min = std::pow(this->gsparams->kvalue_accuracy * 16./35., 1./3.);
_flux_over_2pi = _flux / (2. * M_PI);
_norm = _flux_over_2pi * _inv_r0_sq;
dbg<<"Exponential:\n";
dbg<<"_flux = "<<_flux<<std::endl;
dbg<<"_r0 = "<<_r0<<std::endl;
dbg<<"_ksq_max = "<<_ksq_max<<std::endl;
dbg<<"_ksq_min = "<<_ksq_min<<std::endl;
dbg<<"_norm = "<<_norm<<std::endl;
dbg<<"maxK() = "<<maxK()<<std::endl;
dbg<<"stepK() = "<<stepK()<<std::endl;
}
