nfwlens.h

/*

  This file is a part of GRALE, a library to facilitate the simulation
  and inversion of gravitational lenses.

  Copyright (C) 2008-2012 Jori Liesenborgs

  Contact: jori.liesenborgs@gmail.com
  
  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 2 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, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  
*/

#ifndef GRALE_NFWLENS_H

#define GRALE_NFWLENS_H

#include "graleconfig.h"
#include "symmetriclens.h"
#include "realtype.h"

namespace grale
{

class GRALE_IMPORTEXPORT NFWLensParams : public GravitationalLensParams
{
public:
        NFWLensParams();
        NFWLensParams(double rho_s, double theta_s);
        ~NFWLensParams();

        bool write(serut::SerializationInterface &si) const;
        bool read(serut::SerializationInterface &si);
        GravitationalLensParams *createCopy() const;

        double get3DDensityScale() const                                                                { return m_densityScale3D; }
        double getAngularRadiusScale() const                                                            { return m_angularRadiusScale; }
private:
        double m_densityScale3D;
        double m_angularRadiusScale;
};

class GRALE_IMPORTEXPORT NFWLens : public SymmetricLens
{
public:
        NFWLens();
        ~NFWLens();

        bool getAlphaVectorDerivatives(Vector2D<double> theta, double &axx, double &ayy, double &axy) const;
        bool getProjectedPotential(double D_s, double D_ds, Vector2D<double> theta, double *pPotentialValue) const;
        double getMassInside(double thetaLength) const;
        double getProfileSurfaceMassDensity(double thetaLength) const;
private:
        bool processParameters(const GravitationalLensParams *params);
        static double F(double x);
        static double DF(double x);
        static double P(double x);

        double m_deflectionScale;
        double m_angularRadiusScale;
        double m_potentialScale;
        double m_massScale;
        double m_densityScale;
};

inline double NFWLens::F(double x)
{
        if (x < 1.0)
        {
                double tmp = SQRT(1.0-x*x);
                return ATANH(tmp)/tmp;
        }
        else if (x > 1.0)
        {
                double tmp = SQRT(x*x-1.0);
                return ATAN(tmp)/tmp;
        }
        return 1.0;
}

inline double NFWLens::DF(double x)
{
        double x2 = x*x;

        return (1.0-x2*F(x))/(x*(x2-1.0));
}

inline double NFWLens::P(double x)
{
        if (x < 1.0)
        {
                double l = LN(x/2);
                double at = ATANH(SQRT(1.0-x*x));
                return l*l - at*at;
        }
        else if (x > 1.0)
        {
                double l = LN(x/2);
                double at = ATAN(SQRT(x*x-1.0));
                return l*l + at*at;
        }
        return 0.48045301391820142465;
}

} // end namespace

#endif // GRALE_NFWLENS_H