GModelSpatialElliptical.cpp

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/***************************************************************************
 *  GModelSpatialElliptical.cpp - Abstract elliptical spatial model class  *
 * ----------------------------------------------------------------------- *
 *  copyright (C) 2013-2022 by Juergen Knoedlseder                         *
 * ----------------------------------------------------------------------- *
 *                                                                         *
 *  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 GModelSpatialElliptical.cpp
 * @brief Abstract elliptical spatial model base class implementation
 * @author Juergen Knoedlseder
 */

/* __ Includes ___________________________________________________________ */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "GException.hpp"
#include "GModelSpatialElliptical.hpp"

/* __ Method name definitions ____________________________________________ */
#define G_READ                  "GModelSpatialElliptical::read(GXmlElement&)"
#define G_WRITE                "GModelSpatialElliptical::write(GXmlElement&)"

/* __ Macros _____________________________________________________________ */

/* __ Coding definitions _________________________________________________ */

/* __ Debug definitions __________________________________________________ */


/*==========================================================================
 =                                                                         =
 =                        Constructors/destructors                         =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Void constructor
 ***************************************************************************/
GModelSpatialElliptical::GModelSpatialElliptical(void) : GModelSpatial()
{
    // Initialise members
    init_members();

    // Return
    return;
}


/***********************************************************************//**
 * @brief XML constructor
 *
 * @param[in] xml XML element.
 *
 * Constructs an elliptical spatial model component by extracting information
 * from an XML element. See the read() method for more information about the
 * expected structure of the XML element.
 ***************************************************************************/
GModelSpatialElliptical::GModelSpatialElliptical(const GXmlElement& xml) : 
                         GModelSpatial()
{
    // Initialise members
    init_members();

    // Read information from XML element
    read(xml);

    // Return
    return;
}

/***********************************************************************//**
 * @brief Copy constructor
 *
 * @param[in] model Elliptical spatial model.
 ***************************************************************************/
GModelSpatialElliptical::GModelSpatialElliptical(const GModelSpatialElliptical& model) :
                         GModelSpatial(model)
{
    // Initialise members
    init_members();

    // Copy members
    copy_members(model);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Destructor
 ***************************************************************************/
GModelSpatialElliptical::~GModelSpatialElliptical(void)
{
    // Free members
    free_members();

    // Return
    return;
}


/*==========================================================================
 =                                                                         =
 =                                Operators                                =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Assignment operator
 *
 * @param[in] model Elliptical spatial model.
 * @return Elliptical spatial model.
 ***************************************************************************/
GModelSpatialElliptical& GModelSpatialElliptical::operator=(const GModelSpatialElliptical& model)
{
    // Execute only if object is not identical
    if (this != &model) {

        // Copy base class members
        this->GModelSpatial::operator=(model);

        // Free members
        free_members();

        // Initialise members
        init_members();

        // Copy members
        copy_members(model);

    } // endif: object was not identical

    // Return
    return *this;
}


/*==========================================================================
 =                                                                         =
 =                             Public methods                              =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Return model value
 *
 * @param[in] photon Incident Photon.
 * @param[in] gradients Compute gradients?
 * @return Value of spatial elliptical model.
 *
 * Evaluates the elliptical spatial model value for a specific incident
 * @p photon.
 *
 * If the @p gradients flag is true the method will also compute the
 * parameter gradients for all model parameters.
 ***************************************************************************/
double GModelSpatialElliptical::eval(const GPhoton& photon,
                                     const bool&    gradients) const
{
    // Compute distance from source and position angle (in radians)
    const GSkyDir& srcDir = photon.dir();
    double         theta  = dir().dist(srcDir);
    double         posang = dir().posang(srcDir); // Celestial system

    // Evaluate model
    double value = eval(theta, posang, photon.energy(), photon.time(), gradients);

    // Return result
    return value;
}


/***********************************************************************//**
 * @brief Read model from XML element
 *
 * @param[in] xml XML element.
 *
 * Reads the elliptical source location and position angle information from
 * an XML element in the following format
 *
 *     <spatialModel type="...">
 *       <parameter name="RA"  scale="1" value="83.63" min="-360" max="360" free="1"/>
 *       <parameter name="DEC" scale="1" value="22.01" min="-90"  max="90"  free="1"/>
 *       <parameter name="PA"  scale="1" value="45.0"  min="-360" max="360" free="1"/>
 *       ...
 *     </spatialModel>
 *
 * or
 *
 *     <spatialModel type="...">
 *       <parameter name="GLON" scale="1" value="83.63" min="-360" max="360" free="1"/>
 *       <parameter name="GLAT" scale="1" value="22.01" min="-90"  max="90"  free="1"/>
 *       <parameter name="PA"   scale="1" value="45.0"  min="-360" max="360" free="1"/>
 *       ...
 *     </spatialModel>
 *
 ***************************************************************************/
void GModelSpatialElliptical::read(const GXmlElement& xml)
{
    // Read RA/DEC parameters
    if (gammalib::xml_has_par(xml, "RA") && gammalib::xml_has_par(xml, "DEC")) {

        // Get parameters
        const GXmlElement* ra  = gammalib::xml_get_par(G_READ, xml, "RA");
        const GXmlElement* dec = gammalib::xml_get_par(G_READ, xml, "DEC");

        // Read parameters
        m_lon.read(*ra);
        m_lat.read(*dec);

    }

    // ... otherwise read GLON/GLAT parameters
    else {

        // Get parameters
        const GXmlElement* glon = gammalib::xml_get_par(G_READ, xml, "GLON");
        const GXmlElement* glat = gammalib::xml_get_par(G_READ, xml, "GLAT");

        // Read parameters
        m_lon.read(*glon);
        m_lat.read(*glat);

    }

    // Get other parameters
    const GXmlElement* pa = gammalib::xml_get_par(G_READ, xml, m_posangle.name());

    // Read other parameters
    m_posangle.read(*pa);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Write model into XML element
 *
 * @param[in] xml XML element into which model information is written.
 *
 * Depending on the coordinate system, write the elliptical source
 * information into an XML element with the following format
 *
 *     <spatialModel type="...">
 *       <parameter name="RA"  scale="1" value="83.6331" min="-360" max="360" free="0" />
 *       <parameter name="DEC" scale="1" value="22.0145" min="-90"  max="90"  free="0" />
 *       <parameter name="PA"  scale="1" value="45.0"    min="-360" max="360" free="1" />
 *       ...
 *     </spatialModel>
 *
 * or
 *
 *     <spatialModel type="PointSource">
 *       <parameter name="GLON" scale="1" value="184.5575" min="-360" max="360" free="0" />
 *       <parameter name="GLAT" scale="1" value="-5.7843"  min="-90"  max="90"  free="0" />
 *       <parameter name="PA"   scale="1" value="45.0"     min="-360" max="360" free="1" />
 *       ...
 *     </spatialModel>
 *
 ***************************************************************************/
void GModelSpatialElliptical::write(GXmlElement& xml) const
{
    // Verify model type
    gammalib::xml_check_type(G_WRITE, xml, type());

    // Get or create parameters
    GXmlElement* lon = gammalib::xml_need_par(G_WRITE, xml, m_lon.name());
    GXmlElement* lat = gammalib::xml_need_par(G_WRITE, xml, m_lat.name());
    GXmlElement* pa  = gammalib::xml_need_par(G_WRITE, xml, m_posangle.name());

    // Write parameters
    m_lon.write(*lon);
    m_lat.write(*lat);
    m_posangle.write(*pa);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Return position of elliptical spatial model
 *
 * @return Elliptical spatial model sky direction.
 *
 * Returns the sky direction of the elliptical spatial model.
 ***************************************************************************/
const GSkyDir& GModelSpatialElliptical::dir(void) const
{
    // Get longitude and latitude values
    double lon = m_lon.value();
    double lat = m_lat.value();

    // If longitude or latitude values have changed then update sky
    // direction cache
    if ((lon != m_last_lon) || (lat != m_last_lat)) {

        // Update last values
        m_last_lon = lon;
        m_last_lat = lat;

        // Update sky direction dependent on model coordinate system
        if (is_celestial()) {
            m_dir.radec_deg(m_last_lon, m_last_lat);
        }
        else {
            m_dir.lb_deg(m_last_lon, m_last_lat);
        }

    } // endif: update of sky direction cache required

    // Return sky direction
    return (m_dir);
}


/***********************************************************************//**
 * @brief Set position of radial spatial model
 *
 * @param[in] dir Sky direction of radial spatial model.
 *
 * Sets the sky direction of the radial spatial model.
 ***************************************************************************/
void GModelSpatialElliptical::dir(const GSkyDir& dir)
{
    // Assign sky direction depending on the model coordinate system
    if (is_celestial()) {
        m_lon.value(dir.ra_deg());
        m_lat.value(dir.dec_deg());
    }
    else {
        m_lon.value(dir.l_deg());
        m_lat.value(dir.b_deg());
    }

    // Return
    return;
}


/*==========================================================================
 =                                                                         =
 =                             Private methods                             =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Initialise class members
 ***************************************************************************/
void GModelSpatialElliptical::init_members(void)
{
    // Initialise Right Ascension
    m_lon.clear();
    m_lon.name("RA");
    m_lon.unit("deg");
    m_lon.fix();
    m_lon.scale(1.0);
    m_lon.gradient(0.0);
    m_lon.has_grad(false);

    // Initialise Declination
    m_lat.clear();
    m_lat.name("DEC");
    m_lat.unit("deg");
    m_lat.fix();
    m_lat.scale(1.0);
    m_lat.gradient(0.0);
    m_lat.has_grad(false);

    // Initialise Position Angle
    m_posangle.clear();
    m_posangle.name("PA");
    m_posangle.unit("deg");
    m_posangle.fix();
    m_posangle.scale(1.0);
    m_posangle.gradient(0.0);
    m_posangle.has_grad(false);

    // Initialise semi-major axis
    m_semimajor.clear();
    m_semimajor.name("MajorRadius");
    m_semimajor.unit("deg");
    m_semimajor.value(2.778e-4); // 1 arcsec
    m_semimajor.min(2.778e-4);   // 1 arcsec
    m_semimajor.free();
    m_semimajor.scale(1.0);
    m_semimajor.gradient(0.0);
    m_semimajor.has_grad(false); // Elliptical components never have gradients

    // Initialise semi-minor axis
    m_semiminor.clear();
    m_semiminor.name("MinorRadius");
    m_semiminor.unit("deg");
    m_semiminor.value(2.778e-4); // 1 arcsec
    m_semiminor.min(2.778e-4);   // 1 arcsec
    m_semiminor.free();
    m_semiminor.scale(1.0);
    m_semiminor.gradient(0.0);
    m_semiminor.has_grad(false); // Elliptical components never have gradients

    // Set parameter pointer(s)
    m_pars.clear();
    m_pars.push_back(&m_lon);
    m_pars.push_back(&m_lat);
    m_pars.push_back(&m_posangle);
    m_pars.push_back(&m_semimajor);
    m_pars.push_back(&m_semiminor);

    // Initialise cache
    m_dir.clear();
    m_last_lon = -9999.0;
    m_last_lat = -9999.0;

    // Return
    return;
}


/***********************************************************************//**
 * @brief Copy class members
 *
 * @param[in] model Radial spatial model.
 ***************************************************************************/
void GModelSpatialElliptical::copy_members(const GModelSpatialElliptical& model)
{
    // Copy members
    m_lon       = model.m_lon;
    m_lat       = model.m_lat;
    m_posangle  = model.m_posangle;
    m_semiminor = model.m_semiminor;
    m_semimajor = model.m_semimajor;

    // Set parameter pointer(s)
    m_pars.clear();
    m_pars.push_back(&m_lon);
    m_pars.push_back(&m_lat);
    m_pars.push_back(&m_posangle);
    m_pars.push_back(&m_semimajor);
    m_pars.push_back(&m_semiminor);

    // Copy cache
    m_dir      = model.m_dir;
    m_last_lon = model.m_last_lon;
    m_last_lat = model.m_last_lat;

    // Return
    return;
}


/***********************************************************************//**
 * @brief Delete class members
 ***************************************************************************/
void GModelSpatialElliptical::free_members(void)
{
    // Return
    return;
}