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#ifndef POWER_LAW_SED_H
#define POWER_LAW_SED_H
#include "spectralenergydistribution.h"
#include <aocommon/uvector.h>
#include <schaapcommon/fitters/nlplfitter.h>
#include <schaapcommon/fitters/polynomialfitter.h>
namespace wsclean {
class PowerLawSED final : public SpectralEnergyDistribution {
public:
PowerLawSED() : _referenceFrequency(0.0), _isLogarithmic(true) {
for (size_t p = 0; p != 4; ++p) _factors[p] = 0.0;
}
PowerLawSED(double referenceFrequency, double constantFlux)
: _referenceFrequency(referenceFrequency),
_terms(1),
_isLogarithmic(true) {
double refBrightness = constantFlux;
if (refBrightness <= 0.0) refBrightness = 1.0;
_terms[0] = refBrightness;
_factors[0] = constantFlux / refBrightness;
for (size_t p = 1; p != 4; ++p) _factors[p] = 0.0;
}
virtual PowerLawSED* Clone() const override { return new PowerLawSED(*this); }
virtual std::string ToString() const override {
std::ostringstream str;
str.precision(15);
double term1 = _terms.size() > 1 ? _terms[1] : 0.0;
double f = _terms[0];
double i = f * _factors[0], q = f * _factors[1], u = f * _factors[2],
v = f * _factors[3];
str << " sed {\n frequency " << _referenceFrequency * 1e-6
<< " MHz\n fluxdensity Jy " << i << " " << q << " " << u << " "
<< v << "\n";
if (_isLogarithmic)
str << " spectral-index { ";
else
str << " polynomial { ";
str << term1;
for (size_t i = 2; i < _terms.size(); ++i) str << ", " << _terms[i];
str << " }\n }\n";
return str.str();
}
virtual long double FluxAtFrequencyFromIndex(long double frequencyHz,
size_t pIndex) const override {
if (_isLogarithmic)
return schaapcommon::fitters::NonLinearPowerLawFitter::Evaluate(
frequencyHz / _referenceFrequency, _terms) *
_factors[pIndex];
else
return schaapcommon::fitters::PolynomialFitter::Evaluate(
frequencyHz / _referenceFrequency - 1.0, _terms) *
_factors[pIndex];
}
virtual long double IntegratedFlux(
long double startFrequency, long double endFrequency,
aocommon::PolarizationEnum polarization) const override {
size_t pIndex = aocommon::Polarization::StokesToIndex(polarization);
long double sum = 0.0;
for (size_t i = 0; i != 101; ++i) {
long double frequency =
startFrequency + (endFrequency - startFrequency) * double(i) / 100.0;
sum += FluxAtFrequencyFromIndex(frequency, pIndex);
}
return sum / 101.0;
}
virtual long double AverageFlux(
long double startFrequency, long double endFrequency,
aocommon::PolarizationEnum polarization) const override {
return IntegratedFlux(startFrequency, endFrequency, polarization);
}
virtual bool operator<(
const SpectralEnergyDistribution& other) const override {
return other.FluxAtFrequencyFromIndex(_referenceFrequency, 0) <
FluxAtFrequencyFromIndex(_referenceFrequency, 0);
}
virtual void operator*=(double factor) override {
for (size_t p = 0; p != 4; ++p) _factors[p] *= factor;
}
virtual void operator+=(const SpectralEnergyDistribution&) override {
throw std::runtime_error(
"operator+= not yet implemented for power law sed");
}
virtual long double ReferenceFrequencyHz() const override {
return _referenceFrequency;
}
/**
* @param referenceFrequency Frequency in Hz
* @param brightnessVector A Stokes matrix representing the fluxes at the
* reference frequency
* @param siTerms The SI terms
*/
template <typename Vector>
void SetData(double referenceFrequency, const double* brightnessVector,
const Vector& siTerms) {
_referenceFrequency = referenceFrequency;
double refBrightness = brightnessVector[0];
if (refBrightness <= 0.0) refBrightness = 1.0;
_terms.resize(std::size(siTerms) + 1);
_terms[0] = refBrightness;
for (size_t i = 0; i != std::size(siTerms); ++i) _terms[i + 1] = siTerms[i];
for (size_t p = 0; p != 4; ++p)
_factors[p] = brightnessVector[p] / refBrightness;
}
void SetFromStokesIFit(double referenceFrequency,
const aocommon::UVector<double>& terms) {
_referenceFrequency = referenceFrequency;
double refBrightness = terms[0];
if (refBrightness <= 0.0) refBrightness = 1.0;
_terms.resize(terms.size());
_terms[0] = refBrightness;
for (size_t i = 1; i != terms.size(); ++i) _terms[i] = terms[i];
_factors[0] = terms[0] / refBrightness;
for (size_t p = 1; p != 4; ++p) _factors[p] = 0.0;
}
/**
* Retrieve the parameters for this SED.
*
* The terms are in units as they are regularly found in sky models.
* @param referenceFrequency In Hz the frequency with which the spectral
* function is evaluated.
* @param brightnessVector Flux of Stokes I, Q, U, V in Jy.
* @param siTerms SI index, SI curvature and higher terms.
*/
template <typename Vector>
void GetData(double& referenceFrequency, double* brightnessVector,
Vector& siTerms) const {
referenceFrequency = _referenceFrequency;
double f = _terms[0];
for (size_t p = 0; p != 4; ++p) brightnessVector[p] = f * _factors[p];
siTerms.resize(_terms.size() - 1);
for (size_t i = 0; i != _terms.size() - 1; ++i) siTerms[i] = _terms[i + 1];
}
size_t NTerms() const { return _terms.size(); }
void SetIsLogarithmic(bool isLogarithmic) { _isLogarithmic = isLogarithmic; }
bool IsLogarithmic() const { return _isLogarithmic; }
private:
double _referenceFrequency;
double _factors[4];
std::vector<float> _terms;
bool _isLogarithmic;
};
} // namespace wsclean
#endif
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