source: sasview/sansmodels/src/sans/models/c_extensions/flexible_cylinder.h @ 70bf68c

/*
        TODO: Add 2D model
*/

#if !defined(flexible_cylinder_h)
#define flexible_cylinder_h
/** Structure definition for Flexible cylinder parameters
 * [PYTHONCLASS] = FlexibleCylinderModel
 * [DISP_PARAMS] = length, radius, axis_theta, axis_phi
   [DESCRIPTION] = <text> Note : scale and contrast are both multiplicative factors in the model and are perfectly
                        correlated. One or both of these parameters must be held fixed during model fitting.
                </text>
        [FIXED]= <text>length.width; radius.width; axis_theta.width; axis_phi.width</text>
        [ORIENTATION_PARAMS]= <text>axis_phi; axis_theta; axis_phi.width; axis_theta.width</text>


 **/
typedef struct {
    /// Scale factor
    //  [DEFAULT]=scale=1.0
    double scale;
    /// Length of the flexible cylinder [A]
    //  [DEFAULT]=length=1000 [A]
    double length;
        /// Kuhn length of the flexible cylinder [A]
    //  [DEFAULT]=kuhn_length=100 [A]
    double kuhn_length;
        /// Radius of the flexible cylinder [A]
    //  [DEFAULT]=radius=20.0 [A]
    double radius;
    /// Contrast [1/A²]
    //  [DEFAULT]=contrast=5.3e-6 [1/A²]
    double contrast;
        /// Incoherent Background [1/cm] 
        //  [DEFAULT]=background=0.0001 [1/cm]
        double background;
    /// Orientation of the flexible cylinder axis w/respect incoming beam [rad]
    //  [DEFAULT]=axis_theta=1.0 [rad]
    double axis_theta;
    /// Orientation of the flexible cylinder in the plane of the detector [rad]
    //  [DEFAULT]=axis_phi=1.0 [rad]
    double axis_phi;


} FlexibleCylinderParameters;



/// 1D scattering function
double flexible_cylinder_analytical_1D(FlexibleCylinderParameters *pars, double q);

/// 2D scattering function
double flexible_cylinder_analytical_2D(FlexibleCylinderParameters *pars, double q, double phi);
double flexible_cylinder_analytical_2DXY(FlexibleCylinderParameters *pars, double qx, double qy);
double flexible_cylinder_analytical_2D_scaled(FlexibleCylinderParameters *pars, double q, double q_x, double q_y);

#endif