source: sasview/sansmodels/src/sans/models/c_extensions/cylinder.h @ 19ef1e5

#if !defined(cylinder_h)
#define cylinder_h
/** Structure definition for cylinder parameters
 * [PYTHONCLASS] = CylinderModel
 * [DISP_PARAMS] = radius, length, cyl_theta, cyl_phi
   [DESCRIPTION] = <text>P(q,alpha)= scale/V*f(q)^(2)+bkg
                                                f(q)= 2*(scatter_sld - solvent_sld)*V*sin(qLcos(alpha/2))/[qLcos(alpha/2)]*
                                                J1(qRsin(alpha/2))/[qRsin(alpha)]
                                                V: Volume of the cylinder
                                                R: Radius of the cylinder
                                                L: Length of the cylinder
                                                J1: The bessel function
                                                alpha: angle betweenthe axis of the cylinder and the q-vector
                                                for 1D:the ouput is P(q)=scale/V*integral from pi/2 to zero of f(q)^(2)*
                                                sin(alpha)*dalpha+ bkg
                                        </text>
        [FIXED]= <text>
                                cyl_phi.width; cyl_theta.width; length.width;radius.width
                        </text>
        
 **/
typedef struct {
    /// Scale factor
    //  [DEFAULT]=scale=1.0
    double scale;
    /// Radius of the cylinder [A]
    //  [DEFAULT]=radius=20.0 A
    double radius;
    /// Length of the cylinder [A]
    //  [DEFAULT]=length=400.0 A
    double length;
    /// Contrast [A-2]
    //  [DEFAULT]=contrast=3.0e-6 A-2
    double contrast;
        /// Incoherent Background (cm-1) 0.000
        //  [DEFAULT]=background=0 cm-1
        double background;
    /// Orientation of the cylinder axis w/respect incoming beam [rad]
    //  [DEFAULT]=cyl_theta=1.0 rad
    double cyl_theta;
    /// Orientation of the cylinder in the plane of the detector [rad]
    //  [DEFAULT]=cyl_phi=1.0 rad
    double cyl_phi;
        
} CylinderParameters;



/// 1D scattering function
double cylinder_analytical_1D(CylinderParameters *pars, double q);

/// 2D scattering function
double cylinder_analytical_2D(CylinderParameters *pars, double q, double phi);
double cylinder_analytical_2DXY(CylinderParameters *pars, double qx, double qy);
double cylinder_analytical_2D_scaled(CylinderParameters *pars, double q, double q_x, double q_y);

#endif