GaussianSpectralElement.h

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//# SpectralElement.h: Describes (a set of related) spectral lines
//# Copyright (C) 2001,2003,2004
//# Associated Universities, Inc. Washington DC, USA.
//#
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//# License for more details.
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#ifndef COMPONENTS_GAUSSIANSPECTRALELEMENT_H
#define COMPONENTS_GAUSSIANSPECTRALELEMENT_H

#include <components/SpectralComponents/PCFSpectralElement.h>

namespace casa {

// <summary>
// Describes a Gaussian spectral line
// </summary>

// <use visibility=export>

// <reviewed reviewer="" date="yyyy/mm/dd" tests="tSpectralFit" demos="">
// </reviewed>

// <prerequisite>
//   <li> <linkto module=SpectralElement>SpectralElement</linkto> module
// </prerequisite>
//
// <etymology>
// From Gaussian and spectral line and element
// </etymology>
//
// <synopsis>
// The GaussianSpectralElement class describes a Gaussian spectral line.

// </synopsis>
//
// <example>
// </example>
//
// <motivation>
// To have a container for data descrbing a Gaussian spectral profile for fitting to an observed spectrum
// </motivation>

class GaussianSpectralElement : public PCFSpectralElement {

public:

        // Default constructor creates a default Gaussian element with an amplitude
        // of 1; an integral <src>(sigma=2sqrt(ln2)/pi)</src> of 1;
        // a central frequency of zero. It's necessary for this to be public because
        // Arrays of this class require access to the default constructor. It should never
        // be used in code developers write though.
        GaussianSpectralElement();


        //# Constants
        // Sigma to FWHM conversion factor
        static const casacore::Double SigmaToFWHM;

        //# Constructors

        // Construct with given type and values
        // <thrown>
        //   <li> casacore::AipsError if sigma == 0.0
        //   <li> casacore::AipsError if type not GAUSSIAN
        // </thrown>
        GaussianSpectralElement(
                const casacore::Double ampl, const casacore::Double center,
                const casacore::Double sigma
        );

        // Construct the given tp with the given param
        // <thrown>
        //   <li> casacore::AipsError if incorrect number of parameters (e.g. not 3 for GAUSSIAN)
        //   <li> casacore::AipsError if sigma == 0.0
        // </thrown>
        GaussianSpectralElement(const casacore::Vector<casacore::Double> &param);
        // Copy constructor (deep copy)
        // <thrown>
        //   <li> casacore::AipsError if sigma == 0.0
        // </thrown>
        GaussianSpectralElement(const GaussianSpectralElement &other);

        //#Destructor
        // Destructor
        ~GaussianSpectralElement();

        SpectralElement* clone() const;

        // Assignment (copy semantics)
        // <thrown>
        //   <li> casacore::AipsError if sigma == 0.0
        // </thrown>
//      GaussianSpectralElement& operator=(const GaussianSpectralElement &other);
        // Evaluate the value of the element at x
        //casacore::Double operator()(const casacore::Double x) const;

        casacore::Double getSigma() const;
        casacore::Double getFWHM() const;

        casacore::Double getSigmaErr() const;
        casacore::Double getFWHMErr() const;


        void setSigma(casacore::Double sigma);
        void setFWHM(casacore::Double fwhm);

        void fixSigma(const casacore::Bool fix=true);

        casacore::Bool fixedSigma() const;

        casacore::Double getIntegral() const;

        // Save to a record.   For Gaussian elements,
        // the width is defined as a FWHM in the record interface.
        casacore::Bool toRecord(casacore::RecordInterface &out) const;

        // Sigma to FWHM
        // Convert from sigma to FWHM and vice versa
        // <group>
        static casacore::Double sigmaFromFWHM (const casacore::Double fwhm);

        static casacore::Double sigmaToFWHM (const casacore::Double sigma);
        // </group>

        void set(const casacore::Vector<casacore::Double>& v);

private:
        // need to overrride SpectralElement::_set() because _param[2] is sigma
        // but the second param of the corresponding casacore::Gaussian1D function is the
        // FWHM :(
        void _set(const casacore::Vector<casacore::Double>& v);

};

std::ostream &operator<<(std::ostream& os, const GaussianSpectralElement& elem);


} //# NAMESPACE CASA - END

#endif