GModelSpectralPlaw2.hpp
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/***************************************************************************
* GModelSpectralPlaw2.hpp - Spectral power law model class *
* ----------------------------------------------------------------------- *
* copyright (C) 2011 by Jurgen Knodlseder *
* ----------------------------------------------------------------------- *
* *
* This program is free software: you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation, either version 3 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
* *
***************************************************************************/
/**
* @file GModelSpectralPlaw2.hpp
* @brief Flux normalized power law spectral model class interface definition
* @author J. Knodlseder
*/
#ifndef GMODELSPECTRALPLAW2_HPP
#define GMODELSPECTRALPLAW2_HPP
/* __ Includes ___________________________________________________________ */
#include <string>
#include "GModelPar.hpp"
#include "GModelSpectral.hpp"
#include "GEnergy.hpp"
#include "GXmlElement.hpp"
/***********************************************************************//**
* @class GModelSpectralPlaw2
*
* @brief Flux normalized power law spectral model class
*
* This class implements a power law as the spectral component of the
* gamma-ray sky model.
* The power law function is defined as
* \f[I(E)=integral (index+1)/(emax^{index+1}-emin^{index+1}) E^{index}\f]
* for \f$index \ne -1\f$ and
* \f[I(E)=integral / (\log(emax)-\log(emin)) E^{index}\f]
* for \f$index = -1\f$, where
* \f$integral\f$ is the integral flux between \f$emin\f$ and \f$emax\f$,
* \f$index\f$ is the spectral index,
* \f$emin\f$ is the lower energy limit, and
* \f$emax\f$ is the upper energy limit.
***************************************************************************/
class GModelSpectralPlaw2 : public GModelSpectral {
public:
// Constructors and destructors
GModelSpectralPlaw2(void);
explicit GModelSpectralPlaw2(const double& integral, const double& index);
explicit GModelSpectralPlaw2(const GXmlElement& xml);
GModelSpectralPlaw2(const GModelSpectralPlaw2& model);
virtual ~GModelSpectralPlaw2(void);
// Operators
virtual GModelSpectralPlaw2& operator= (const GModelSpectralPlaw2& model);
// Implemented pure virtual methods
virtual void clear(void);
virtual GModelSpectralPlaw2* clone(void) const;
virtual std::string type(void) const { return "PowerLaw2"; }
virtual double eval(const GEnergy& srcEng) const;
virtual double eval_gradients(const GEnergy& srcEng) const;
virtual double flux(const GEnergy& emin, const GEnergy& emax) const;
virtual double eflux(const GEnergy& emin, const GEnergy& emax) const;
virtual GEnergy mc(const GEnergy& emin, const GEnergy& emax, GRan& ran) const;
virtual void read(const GXmlElement& xml);
virtual void write(GXmlElement& xml) const;
virtual std::string print(void) const;
// Other methods
double integral(void) const { return m_integral.real_value(); }
double index(void) const { return m_index.real_value(); }
double emin(void) const { return m_emin.real_value(); }
double emax(void) const { return m_emax.real_value(); }
protected:
// Protected methods
void init_members(void);
void copy_members(const GModelSpectralPlaw2& model);
void free_members(void);
void update(const GEnergy& srcEng) const;
// Protected members
GModelPar m_integral; //!< Integral flux
GModelPar m_index; //!< Spectral index
GModelPar m_emin; //!< Lower energy limit (MeV)
GModelPar m_emax; //!< Upper energy limit (MeV)
// Cached members used for pre-computations
mutable double m_log_emin; //!< Log(emin)
mutable double m_log_emax; //!< Log(emax)
mutable double m_pow_emin; //!< emin^(index+1)
mutable double m_pow_emax; //!< emax^(index+1)
mutable double m_norm; //!< Power-law normalization (for pivot energy 1 MeV)
mutable double m_g_norm; //!< Power-law normalization gradient
mutable double m_power; //!< Power-law factor
mutable double m_last_integral; //!< Last integral flux
mutable double m_last_index; //!< Last spectral index (MeV)
mutable double m_last_emin; //!< Last lower energy limit (MeV)
mutable double m_last_emax; //!< Last upper energy limit (MeV)
mutable GEnergy m_last_energy; //!< Last source energy
mutable double m_last_value; //!< Last function value
mutable double m_last_g_integral; //!< Last integral flux gradient
mutable double m_last_g_index; //!< Last spectral index gradient
};
#endif /* GMODELSPECTRALPLAW2_HPP */