#if !defined(ellipsoid_h)
#define ellipsoid_h
#include "parameters.hh"

/**
 * Structure definition for ellipsoid parameters
 * The ellipsoid has axes radius_b, radius_b, radius_a.
 * Ref: Jan Skov Pedersen, Advances in Colloid and Interface Science, 70 (1997) 171-210
 */
//[PYTHONCLASS] = EllipsoidModel
//[DISP_PARAMS] = radius_a, radius_b, axis_theta, axis_phi
//[DESCRIPTION] = <text>"P(q.alpha)= scale*f(q)^(2)+ bkg, where f(q)= 3*(sld_ell
//		- sld_solvent)*V*[sin(q*r(Ra,Rb,alpha))
//		-q*r*cos(qr(Ra,Rb,alpha))]
//		/[qr(Ra,Rb,alpha)]^(3)"
//
//     r(Ra,Rb,alpha)= [Rb^(2)*(sin(alpha))^(2)
//     + Ra^(2)*(cos(alpha))^(2)]^(1/2)
//
//		scatter_sld: SLD of the scatter
//		solvent_sld: SLD of the solvent
//     sldEll: SLD of ellipsoid
//		sldSolv: SLD of solvent
//		V: volune of the Eliipsoid
//		Ra: radius along the rotation axis
//		of the Ellipsoid
//		Rb: radius perpendicular to the
//		rotation axis of the ellipsoid
//		</text>
//[FIXED]= <text> axis_phi.width; axis_theta.width;radius_a.width;
//radius_b.width; length.width; r_minor.width;
//r_ratio.width</text>
//[ORIENTATION_PARAMS]=  axis_phi.width; axis_theta.width;axis_phi; axis_theta

class EllipsoidModel{
public:
  // Model parameters
  /// Rotation axis radius_a [A]
  //  [DEFAULT]=radius_a=20.0 [A]
  Parameter radius_a;

  /// Scale factor
  //  [DEFAULT]=scale=1.0
  Parameter scale;

  /// Radius_b [A]
  //  [DEFAULT]=radius_b=400 [A]
  Parameter radius_b;

  /// sldEll [1/A^(2)]
  //  [DEFAULT]=sldEll=4.0e-6 [1/A^(2)]
  Parameter sldEll;

  /// sld of solvent [1/A^(2)]
  //  [DEFAULT]=sldSolv=1.0e-6 [1/A^(2)]
  Parameter sldSolv;

  /// Incoherent Background [1/cm]
  //  [DEFAULT]=background=0 [1/cm]
  Parameter background;

  /// Orientation of the long axis of the ellipsoid w/respect incoming beam [deg]
  //  [DEFAULT]=axis_theta=90.0 [deg]
  Parameter axis_theta;
  /// Orientation of the long axis of the ellipsoid in the plane of the detector [deg]
  //  [DEFAULT]=axis_phi=0.0 [deg]
  Parameter axis_phi;

  // Constructor
  EllipsoidModel();

  // Operators to get I(Q)
  double operator()(double q);
  double operator()(double qx, double qy);
  double calculate_ER();
  double calculate_VR();
  double evaluate_rphi(double q, double phi);
};


#endif