/*******************************************************************************
*
* McXtrace, X-ray tracing package
*         Copyright, All rights reserved
*         DTU Physics, Kgs. Lyngby, Denmark
*         Synchrotron SOLEIL, Saint-Aubin, France
*
* Component: SasView_core_shell_bicelle
*
* %Identification
* Written by: Jose Robledo
* Based on sasmodels from SasView
* Origin: FZJ / DTU / ESS DMSC
*
*
* SasView core_shell_bicelle model component as sample description.
*
* %Description
*
* SasView_core_shell_bicelle component, generated from core_shell_bicelle.c in sasmodels.
*
* Example: 
*  SasView_core_shell_bicelle(radius, thick_rim, thick_face, length, sld_core, sld_face, sld_rim, sld_solvent, 
*     model_scale=1.0, model_abs=0.0, xwidth=0.01, yheight=0.01, zdepth=0.005, R=0, 
*     int target_index=1, target_x=0, target_y=0, target_z=1,
*     focus_xw=0.5, focus_yh=0.5, focus_aw=0, focus_ah=0, focus_r=0, 
*     pd_radius=0.0, pd_thick_rim=0.0, pd_thick_face=0.0, pd_length=0.0)
*
* %Parameters
* INPUT PARAMETERS:
* radius: [Ang] ([0, inf]) Cylinder core radius.
* thick_rim: [Ang] ([0, inf]) Rim shell thickness.
* thick_face: [Ang] ([0, inf]) Cylinder face thickness.
* length: [Ang] ([0, inf]) Cylinder length.
* sld_core: [1e-6/Ang^2] ([-inf, inf]) Cylinder core scattering length density.
* sld_face: [1e-6/Ang^2] ([-inf, inf]) Cylinder face scattering length density.
* sld_rim: [1e-6/Ang^2] ([-inf, inf]) Cylinder rim scattering length density.
* sld_solvent: [1e-6/Ang^2] ([-inf, inf]) Solvent scattering length density.
* Optional parameters:
* model_abs: [ ] Absorption cross section density at 2200 m/s.
* model_scale: [ ] Global scale factor for scattering kernel. For systems without inter-particle interference, the form factors can be related to the scattering intensity by the particle volume fraction.
* xwidth: [m] ([-inf, inf]) Horiz. dimension of sample, as a width.
* yheight: [m] ([-inf, inf]) vert . dimension of sample, as a height for cylinder/box
* zdepth: [m] ([-inf, inf]) depth of sample
* R: [m] Outer radius of sample in (x,z) plane for cylinder/sphere.
* target_x: [m] relative focus target position.
* target_y: [m] relative focus target position.
* target_z: [m] relative focus target position.
* target_index: [ ] Relative index of component to focus at, e.g. next is +1.
* focus_xw: [m] horiz. dimension of a rectangular area.
* focus_yh: [m], vert. dimension of a rectangular area.
* focus_aw: [deg], horiz. angular dimension of a rectangular area.
* focus_ah: [deg], vert. angular dimension of a rectangular area.
* focus_r: [m] case of circular focusing, focusing radius.
* pd_radius: [] (0,inf) defined as (dx/x), where x is de mean value and dx the standard devition of the variable.
* pd_thick_rim: [] (0,inf) defined as (dx/x), where x is de mean value and dx the standard devition of the variable.
* pd_thick_face: [] (0,inf) defined as (dx/x), where x is de mean value and dx the standard devition of the variable.
* pd_length: [] (0,inf) defined as (dx/x), where x is de mean value and dx the standard devition of the variable
*
* %Link
* %End
*******************************************************************************/
DEFINE COMPONENT SasView_core_shell_bicelle

SETTING PARAMETERS (
        radius=80,
        thick_rim=10,
        thick_face=10,
        length=50,
        sld_core=1,
        sld_face=4,
        sld_rim=4,
        sld_solvent=1,
        model_scale=1.0,
        model_abs=0.0,
        xwidth=0.01,
        yheight=0.01,
        zdepth=0.005,
        R=0,
        target_x=0,
        target_y=0,
        target_z=1,
        int target_index=1,
        focus_xw=0.5,
        focus_yh=0.5,
        focus_aw=0,
        focus_ah=0,
        focus_r=0,
        pd_radius=0.0,
        pd_thick_rim=0.0,
        pd_thick_face=0.0,
        pd_length=0.0)


SHARE %{
%include "sas_kernel_header.c"

/* BEGIN Required header for SASmodel core_shell_bicelle */
#define HAS_Iqac
#define HAS_FQ
#define FORM_VOL

#ifndef SAS_HAVE_sas_Si
#define SAS_HAVE_sas_Si

#line 1 "sas_Si"
// integral of sin(x)/x Taylor series approximated to w/i 0.1%
double sas_Si(double x);

    
#pragma acc routine seq
double sas_Si(double x)
{
    if (x >= M_PI*6.2/4.0) {
        const double xxinv = 1./(x*x);
        // Explicitly writing factorial values triples the speed of the calculation
        const double out_cos = (((-720.*xxinv + 24.)*xxinv - 2.)*xxinv + 1.)/x;
        const double out_sin = (((-5040.*xxinv + 120.)*xxinv - 6.)*xxinv + 1)*xxinv;

        double sin_x, cos_x;
        SINCOS(x, sin_x, cos_x);
        return M_PI_2 - cos_x*out_cos - sin_x*out_sin;
    } else {
        const double xx = x*x;
        // Explicitly writing factorial values triples the speed of the calculation
        return (((((-1./439084800.*xx
            + 1./3265920.)*xx
            - 1./35280.)*xx
            + 1./600.)*xx
            - 1./18.)*xx
            + 1.)*x;
    }
}


#endif // SAS_HAVE_sas_Si


#ifndef SAS_HAVE_polevl
#define SAS_HAVE_polevl

#line 1 "polevl"
/*							polevl.c
 *							p1evl.c
 *
 *	Evaluate polynomial
 *
 *
 *
 * SYNOPSIS:
 *
 * int N;
 * double x, y, coef[N+1], polevl[];
 *
 * y = polevl( x, coef, N );
 *
 *
 *
 * DESCRIPTION:
 *
 * Evaluates polynomial of degree N:
 *
 *                     2          N
 * y  =  C  + C x + C x  +...+ C x
 *        0    1     2          N
 *
 * Coefficients are stored in reverse order:
 *
 * coef[0] = C  , ..., coef[N] = C  .
 *            N                   0
 *
 * The function p1evl() assumes that C_N = 1.0 and is
 * omitted from the array.  Its calling arguments are
 * otherwise the same as polevl().
 *
 *
 * SPEED:
 *
 * In the interest of speed, there are no checks for out
 * of bounds arithmetic.  This routine is used by most of
 * the functions in the library.  Depending on available
 * equipment features, the user may wish to rewrite the
 * program in microcode or assembly language.
 *
 */


/*
Cephes Math Library Release 2.1:  December, 1988
Copyright 1984, 1987, 1988 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140
*/
#pragma acc routine seq
static
double polevl( double x, pconstant double *coef, int N )
{

    int i = 0;
    double ans = coef[i];

    while (i < N) {
        i++;
        ans = ans * x + coef[i];
    }

    return ans;
}

/*							p1evl()	*/
/*                                          N
 * Evaluate polynomial when coefficient of x  is 1.0.
 * Otherwise same as polevl.
 */
#pragma acc routine seq
static
double p1evl( double x, pconstant double *coef, int N )
{
    int i=0;
    double ans = x+coef[i];

    while (i < N-1) {
        i++;
        ans = ans*x + coef[i];
    }

    return ans;
}


#endif // SAS_HAVE_polevl


#ifndef SAS_HAVE_sas_J1
#define SAS_HAVE_sas_J1

#line 1 "sas_J1"
/*							j1.c
 *
 *	Bessel function of order one
 *
 *
 *
 * SYNOPSIS:
 *
 * double x, y, j1();
 *
 * y = j1( x );
 *
 *
 *
 * DESCRIPTION:
 *
 * Returns Bessel function of order one of the argument.
 *
 * The domain is divided into the intervals [0, 8] and
 * (8, infinity). In the first interval a 24 term Chebyshev
 * expansion is used. In the second, the asymptotic
 * trigonometric representation is employed using two
 * rational functions of degree 5/5.
 *
 *
 *
 * ACCURACY:
 *
 *                      Absolute error:
 * arithmetic   domain      # trials      peak         rms
 *    DEC       0, 30       10000       4.0e-17     1.1e-17
 *    IEEE      0, 30       30000       2.6e-16     1.1e-16
 *
 *
 */

/*
Cephes Math Library Release 2.8:  June, 2000
Copyright 1984, 1987, 1989, 2000 by Stephen L. Moshier
*/

#if FLOAT_SIZE>4
//Cephes double pression function

constant double RPJ1[8] = {
    -8.99971225705559398224E8,
    4.52228297998194034323E11,
    -7.27494245221818276015E13,
    3.68295732863852883286E15,
    0.0,
    0.0,
    0.0,
    0.0 };

constant double RQJ1[8] = {
    6.20836478118054335476E2,
    2.56987256757748830383E5,
    8.35146791431949253037E7,
    2.21511595479792499675E10,
    4.74914122079991414898E12,
    7.84369607876235854894E14,
    8.95222336184627338078E16,
    5.32278620332680085395E18
    };

constant double PPJ1[8] = {
    7.62125616208173112003E-4,
    7.31397056940917570436E-2,
    1.12719608129684925192E0,
    5.11207951146807644818E0,
    8.42404590141772420927E0,
    5.21451598682361504063E0,
    1.00000000000000000254E0,
    0.0} ;


constant double PQJ1[8] = {
    5.71323128072548699714E-4,
    6.88455908754495404082E-2,
    1.10514232634061696926E0,
    5.07386386128601488557E0,
    8.39985554327604159757E0,
    5.20982848682361821619E0,
    9.99999999999999997461E-1,
    0.0 };

constant double QPJ1[8] = {
    5.10862594750176621635E-2,
    4.98213872951233449420E0,
    7.58238284132545283818E1,
    3.66779609360150777800E2,
    7.10856304998926107277E2,
    5.97489612400613639965E2,
    2.11688757100572135698E2,
    2.52070205858023719784E1 };

constant double QQJ1[8] = {
    7.42373277035675149943E1,
    1.05644886038262816351E3,
    4.98641058337653607651E3,
    9.56231892404756170795E3,
    7.99704160447350683650E3,
    2.82619278517639096600E3,
    3.36093607810698293419E2,
    0.0 };

#pragma acc declare copyin( RPJ1[0:8], RQJ1[0:8], PPJ1[0:8], PQJ1[0:8], QPJ1[0:8], QQJ1[0:8])

#pragma acc routine seq
static
double cephes_j1(double x)
{

    double w, z, p, q, abs_x, sign_x;

    const double Z1 = 1.46819706421238932572E1;
    const double Z2 = 4.92184563216946036703E1;

    // 2017-05-18 PAK - mathematica and mpmath use J1(-x) = -J1(x)
    if (x < 0) {
        abs_x = -x;
        sign_x = -1.0;
    } else {
        abs_x = x;
        sign_x = 1.0;
    }

    if( abs_x <= 5.0 ) {
        z = abs_x * abs_x;
        w = polevl( z, RPJ1, 3 ) / p1evl( z, RQJ1, 8 );
        w = w * abs_x * (z - Z1) * (z - Z2);
        return( sign_x * w );
    }

    w = 5.0/abs_x;
    z = w * w;
    p = polevl( z, PPJ1, 6)/polevl( z, PQJ1, 6 );
    q = polevl( z, QPJ1, 7)/p1evl( z, QQJ1, 7 );

    // 2017-05-19 PAK improve accuracy using trig identies
    // original:
    //    const double THPIO4 =  2.35619449019234492885;
    //    const double SQ2OPI = 0.79788456080286535588;
    //    double sin_xn, cos_xn;
    //    SINCOS(abs_x - THPIO4, sin_xn, cos_xn);
    //    p = p * cos_xn - w * q * sin_xn;
    //    return( sign_x * p * SQ2OPI / sqrt(abs_x) );
    // expanding p*cos(a - 3 pi/4) - wq sin(a - 3 pi/4)
    //    [ p(sin(a) - cos(a)) + wq(sin(a) + cos(a)) / sqrt(2)
    // note that sqrt(1/2) * sqrt(2/pi) = sqrt(1/pi)
    const double SQRT1_PI = 0.56418958354775628;
    double sin_x, cos_x;
    SINCOS(abs_x, sin_x, cos_x);
    p = p*(sin_x - cos_x) + w*q*(sin_x + cos_x);
    return( sign_x * p * SQRT1_PI / sqrt(abs_x) );
}

#else
//Single precission version of cephes

constant float JPJ1[8] = {
    -4.878788132172128E-009,
    6.009061827883699E-007,
    -4.541343896997497E-005,
    1.937383947804541E-003,
    -3.405537384615824E-002,
    0.0,
    0.0,
    0.0
    };

constant float MO1J1[8] = {
    6.913942741265801E-002,
    -2.284801500053359E-001,
    3.138238455499697E-001,
    -2.102302420403875E-001,
    5.435364690523026E-003,
    1.493389585089498E-001,
    4.976029650847191E-006,
    7.978845453073848E-001
    };

constant float PH1J1[8] = {
    -4.497014141919556E+001,
    5.073465654089319E+001,
    -2.485774108720340E+001,
    7.222973196770240E+000,
    -1.544842782180211E+000,
    3.503787691653334E-001,
    -1.637986776941202E-001,
    3.749989509080821E-001
    };

#pragma acc declare copyin( JPJ1[0:8], MO1J1[0:8], PH1J1[0:8])

#pragma acc routine seq
static
float cephes_j1f(float xx)
{

    float x, w, z, p, q, xn;

    const float Z1 = 1.46819706421238932572E1;


    // 2017-05-18 PAK - mathematica and mpmath use J1(-x) = -J1(x)
    x = xx;
    if( x < 0 )
        x = -xx;

    if( x <= 2.0 ) {
        z = x * x;
        p = (z-Z1) * x * polevl( z, JPJ1, 4 );
        return( xx < 0. ? -p : p );
    }

    q = 1.0/x;
    w = sqrt(q);

    p = w * polevl( q, MO1J1, 7);
    w = q*q;
    // 2017-05-19 PAK improve accuracy using trig identies
    // original:
    //    const float THPIO4F =  2.35619449019234492885;    /* 3*pi/4 */
    //    xn = q * polevl( w, PH1J1, 7) - THPIO4F;
    //    p = p * cos(xn + x);
    //    return( xx < 0. ? -p : p );
    // expanding cos(a + b - 3 pi/4) is
    //    [sin(a)sin(b) + sin(a)cos(b) + cos(a)sin(b)-cos(a)cos(b)] / sqrt(2)
    xn = q * polevl( w, PH1J1, 7);
    float cos_xn, sin_xn;
    float cos_x, sin_x;
    SINCOS(xn, sin_xn, cos_xn);  // about xn and 1
    SINCOS(x, sin_x, cos_x);
    p *= M_SQRT1_2*(sin_xn*(sin_x+cos_x) + cos_xn*(sin_x-cos_x));

    return( xx < 0. ? -p : p );
}
#endif

#if FLOAT_SIZE>4
#define sas_J1 cephes_j1
#else
#define sas_J1 cephes_j1f
#endif

//Finally J1c function that equals 2*J1(x)/x
    
#pragma acc routine seq
static
double sas_2J1x_x(double x)
{
    return (x != 0.0 ) ? 2.0*sas_J1(x)/x : 1.0;
}


#endif // SAS_HAVE_sas_J1


#ifndef SAS_HAVE_gauss76
#define SAS_HAVE_gauss76

#line 1 "gauss76"
// Created by Andrew Jackson on 4/23/07

 #ifdef GAUSS_N
 # undef GAUSS_N
 # undef GAUSS_Z
 # undef GAUSS_W
 #endif
 #define GAUSS_N 76
 #define GAUSS_Z Gauss76Z
 #define GAUSS_W Gauss76Wt

// Gaussians
constant double Gauss76Wt[76] = {
	.00126779163408536,		//0
	.00294910295364247,
	.00462793522803742,
	.00629918049732845,
	.00795984747723973,
	.00960710541471375,
	.0112381685696677,
	.0128502838475101,
	.0144407317482767,
	.0160068299122486,
	.0175459372914742,		//10
	.0190554584671906,
	.020532847967908,
	.0219756145344162,
	.0233813253070112,
	.0247476099206597,
	.026072164497986,
	.0273527555318275,
	.028587223650054,
	.029773487255905,
	.0309095460374916,		//20
	.0319934843404216,
	.0330234743977917,
	.0339977794120564,
	.0349147564835508,
	.0357728593807139,
	.0365706411473296,
	.0373067565423816,
	.0379799643084053,
	.0385891292645067,
	.0391332242205184,		//30
	.0396113317090621,
	.0400226455325968,
	.040366472122844,
	.0406422317102947,
	.0408494593018285,
	.040987805464794,
	.0410570369162294,
	.0410570369162294,
	.040987805464794,
	.0408494593018285,		//40
	.0406422317102947,
	.040366472122844,
	.0400226455325968,
	.0396113317090621,
	.0391332242205184,
	.0385891292645067,
	.0379799643084053,
	.0373067565423816,
	.0365706411473296,
	.0357728593807139,		//50
	.0349147564835508,
	.0339977794120564,
	.0330234743977917,
	.0319934843404216,
	.0309095460374916,
	.029773487255905,
	.028587223650054,
	.0273527555318275,
	.026072164497986,
	.0247476099206597,		//60
	.0233813253070112,
	.0219756145344162,
	.020532847967908,
	.0190554584671906,
	.0175459372914742,
	.0160068299122486,
	.0144407317482767,
	.0128502838475101,
	.0112381685696677,
	.00960710541471375,		//70
	.00795984747723973,
	.00629918049732845,
	.00462793522803742,
	.00294910295364247,
	.00126779163408536		//75 (indexed from 0)
};

constant double Gauss76Z[76] = {
	-.999505948362153,		//0
	-.997397786355355,
	-.993608772723527,
	-.988144453359837,
	-.981013938975656,
	-.972229228520377,
	-.961805126758768,
	-.949759207710896,
	-.936111781934811,
	-.92088586125215,
	-.904107119545567,		//10
	-.885803849292083,
	-.866006913771982,
	-.844749694983342,
	-.822068037328975,
	-.7980001871612,
	-.77258672828181,
	-.74587051350361,
	-.717896592387704,
	-.688712135277641,
	-.658366353758143,		//20
	-.626910417672267,
	-.594397368836793,
	-.560882031601237,
	-.526420920401243,
	-.491072144462194,
	-.454895309813726,
	-.417951418780327,
	-.380302767117504,
	-.342012838966962,
	-.303146199807908,		//30
	-.263768387584994,
	-.223945802196474,
	-.183745593528914,
	-.143235548227268,
	-.102483975391227,
	-.0615595913906112,
	-.0205314039939986,
	.0205314039939986,
	.0615595913906112,
	.102483975391227,			//40
	.143235548227268,
	.183745593528914,
	.223945802196474,
	.263768387584994,
	.303146199807908,
	.342012838966962,
	.380302767117504,
	.417951418780327,
	.454895309813726,
	.491072144462194,		//50
	.526420920401243,
	.560882031601237,
	.594397368836793,
	.626910417672267,
	.658366353758143,
	.688712135277641,
	.717896592387704,
	.74587051350361,
	.77258672828181,
	.7980001871612,	//60
	.822068037328975,
	.844749694983342,
	.866006913771982,
	.885803849292083,
	.904107119545567,
	.92088586125215,
	.936111781934811,
	.949759207710896,
	.961805126758768,
	.972229228520377,		//70
	.981013938975656,
	.988144453359837,
	.993608772723527,
	.997397786355355,
	.999505948362153		//75
};


#pragma acc declare copyin(Gauss76Wt[0:76], Gauss76Z[0:76])

#endif // SAS_HAVE_gauss76


#ifndef SAS_HAVE_core_shell_bicelle
#define SAS_HAVE_core_shell_bicelle

#line 1 "core_shell_bicelle"
static double
form_volume_core_shell_bicelle(double radius, double thick_rim, double thick_face, double length)
{
    return M_PI*square(radius+thick_rim)*(length+2.0*thick_face);
}

static double
bicelle_kernel(double qab,
    double qc,
    double radius,
    double thick_radius,
    double thick_face,
    double halflength,
    double sld_core,
    double sld_face,
    double sld_rim,
    double sld_solvent)
{
    const double dr1 = sld_core-sld_face;
    const double dr2 = sld_rim-sld_solvent;
    const double dr3 = sld_face-sld_rim;
    const double vol1 = M_PI*square(radius)*2.0*(halflength);
    const double vol2 = M_PI*square(radius+thick_radius)*2.0*(halflength+thick_face);
    const double vol3 = M_PI*square(radius)*2.0*(halflength+thick_face);

    const double be1 = sas_2J1x_x((radius)*qab);
    const double be2 = sas_2J1x_x((radius+thick_radius)*qab);
    const double si1 = sas_sinx_x((halflength)*qc);
    const double si2 = sas_sinx_x((halflength+thick_face)*qc);

    const double t = vol1*dr1*si1*be1 +
                     vol2*dr2*si2*be2 +
                     vol3*dr3*si2*be1;

    return t;
}

static double
radius_from_excluded_volume_core_shell_bicelle(double radius, double thick_rim, double thick_face, double length)
{
    const double radius_tot = radius + thick_rim;
    const double length_tot = length + 2.0*thick_face;
    return 0.5*cbrt(0.75*radius_tot*(2.0*radius_tot*length_tot + (radius_tot + length_tot)*(M_PI*radius_tot + length_tot)));
}

static double
radius_from_volume_core_shell_bicelle(double radius, double thick_rim, double thick_face, double length)
{
    const double volume_bicelle = form_volume_core_shell_bicelle(radius,thick_rim,thick_face,length);
    return cbrt(volume_bicelle/M_4PI_3);
}

static double
radius_from_diagonal_core_shell_bicelle(double radius, double thick_rim, double thick_face, double length)
{
    const double radius_tot = radius + thick_rim;
    const double length_tot = length + 2.0*thick_face;
    return sqrt(radius_tot*radius_tot + 0.25*length_tot*length_tot);
}

static double
radius_effective_core_shell_bicelle(int mode, double radius, double thick_rim, double thick_face, double length)
{
    switch (mode) {
    default:
    case 1: // equivalent cylinder excluded volume
        return radius_from_excluded_volume_core_shell_bicelle(radius, thick_rim, thick_face, length);
    case 2: // equivalent sphere
        return radius_from_volume_core_shell_bicelle(radius, thick_rim, thick_face, length);
    case 3: // outer rim radius
        return radius + thick_rim;
    case 4: // half outer thickness
        return 0.5*length + thick_face;
    case 5: // half diagonal
        return radius_from_diagonal_core_shell_bicelle(radius,thick_rim,thick_face,length);
    }
}

static void
Fq_core_shell_bicelle(double q,
    double *F1,
    double *F2,
    double radius,
    double thick_radius,
    double thick_face,
    double length,
    double sld_core,
    double sld_face,
    double sld_rim,
    double sld_solvent)
{
    // set up the integration end points
    const double uplim = M_PI_4;
    const double halflength = 0.5*length;

    double total_F1 = 0.0;
    double total_F2 = 0.0;
    for(int i=0;i<GAUSS_N;i++) {
        double theta = (GAUSS_Z[i] + 1.0)*uplim;
        double sin_theta, cos_theta; // slots to hold sincos function output
        SINCOS(theta, sin_theta, cos_theta);
        double form = bicelle_kernel(q*sin_theta, q*cos_theta, radius, thick_radius, thick_face,
                                   halflength, sld_core, sld_face, sld_rim, sld_solvent);
        total_F1 += GAUSS_W[i]*form*sin_theta;
        total_F2 += GAUSS_W[i]*form*form*sin_theta;
    }
    // Correct for integration range
    total_F1 *= uplim;
    total_F2 *= uplim;

    *F1 = 1.0e-2*total_F1;
    *F2 = 1.0e-4*total_F2;
}

static double
Iqac_core_shell_bicelle(double qab, double qc,
    double radius,
    double thick_rim,
    double thick_face,
    double length,
    double core_sld,
    double face_sld,
    double rim_sld,
    double solvent_sld)
{
    double fq = bicelle_kernel(qab, qc, radius, thick_rim, thick_face,
                           0.5*length, core_sld, face_sld, rim_sld,
                           solvent_sld);
    return 1.0e-4*fq*fq;
}


#endif // SAS_HAVE_core_shell_bicelle



/* END Required header for SASmodel core_shell_bicelle */
%}
    DECLARE
%{
  double shape;
  double my_a_k;
%}

INITIALIZE
%{
  shape = -1; /* -1:no shape, 0:cyl, 1:box, 2:sphere  */
  if (xwidth && yheight && zdepth)
    shape = 1;
  else if (R > 0 && yheight)
    shape = 0;
  else if (R > 0 && !yheight)
    shape = 2;
  if (shape < 0)
    exit (fprintf (stderr,
                   "SasView_model: %s: sample has invalid dimensions.\n"
                   "ERROR     Please check parameter values.\n",
                   NAME_CURRENT_COMP));

  /* now compute target coords if a component index is supplied */
  if (!target_index && !target_x && !target_y && !target_z)
    target_index = 1;
  if (target_index) {
    Coords ToTarget;
    ToTarget = coords_sub (POS_A_COMP_INDEX (INDEX_CURRENT_COMP + target_index), POS_A_CURRENT_COMP);
    ToTarget = rot_apply (ROT_A_CURRENT_COMP, ToTarget);
    coords_get (ToTarget, &target_x, &target_y, &target_z);
  }

  if (!(target_x || target_y || target_z)) {
    printf ("SasView_model: %s: The target is not defined. Using direct beam (Z-axis).\n", NAME_CURRENT_COMP);
    target_z = 1;
  }

  /*TODO fix absorption*/
  my_a_k = model_abs; /* assume absorption is given in 1/m */
%}


TRACE
%{
  double l0, l1, k, l_full, l, dl, d_Phi;
  double aim_x = 0, aim_y = 0, aim_z = 1, axis_x, axis_y, axis_z;
  double f, solid_angle, kx_i, ky_i, kz_i, q, qx, qy, qz;
  char intersect = 0;

  /* Intersection photon trajectory / sample (sample surface) */
  if (shape == 0) {
    intersect = cylinder_intersect (&l0, &l1, x, y, z, kx, ky, kz, R, yheight);
  } else if (shape == 1) {
    intersect = box_intersect (&l0, &l1, x, y, z, kx, ky, kz, xwidth, yheight, zdepth);
  } else if (shape == 2) {
    intersect = sphere_intersect (&l0, &l1, x, y, z, kx, ky, kz, R);
  }
  if (intersect) {
    if (l0 < 0)
      ABSORB;

    /* Photon enters at l0. */
    k = sqrt (kx * kx + ky * ky + kz * kz);
    l_full = (l1 - l0);              /* Length of full path through sample */
    dl = rand01 () * (l1 - l0) + l0; /* Point of scattering */
    PROP_DL (dl);                    /* Point of scattering */
    l = (dl - l0);                   /* Penetration in sample */

    kx_i = kx;
    ky_i = ky;
    kz_i = kz;
    if ((target_x || target_y || target_z)) {
      aim_x = target_x - x; /* Vector pointing at target (anal./det.) */
      aim_y = target_y - y;
      aim_z = target_z - z;
    }
    if (focus_aw && focus_ah) {
      randvec_target_rect_angular (&kx, &ky, &kz, &solid_angle, aim_x, aim_y, aim_z, focus_aw, focus_ah, ROT_A_CURRENT_COMP);
    } else if (focus_xw && focus_yh) {
      randvec_target_rect (&kx, &ky, &kz, &solid_angle, aim_x, aim_y, aim_z, focus_xw, focus_yh, ROT_A_CURRENT_COMP);
    } else {
      randvec_target_circle (&kx, &ky, &kz, &solid_angle, aim_x, aim_y, aim_z, focus_r);
    }
    NORM (kx, ky, kz);
    kx *= k;
    ky *= k;
    kz *= k;
    qx = (kx_i - kx);
    qy = (ky_i - ky);
    qz = (kz_i - kz);
    q = sqrt (qx * qx + qy * qy + qz * qz);

    double trace_radius = radius;
    double trace_thick_rim = thick_rim;
    double trace_thick_face = thick_face;
    double trace_length = length;
    if (pd_radius != 0.0 || pd_thick_rim != 0.0 || pd_thick_face != 0.0 || pd_length != 0.0) {
      trace_radius = (randnorm () * pd_radius + 1.0) * radius;
      trace_thick_rim = (randnorm () * pd_thick_rim + 1.0) * thick_rim;
      trace_thick_face = (randnorm () * pd_thick_face + 1.0) * thick_face;
      trace_length = (randnorm () * pd_length + 1.0) * length;
    }

    // Sample dependent. Retrieved from SasView./////////////////////
    float Iq_out;
    Iq_out = 1;

    double F1 = 0.0, F2 = 0.0;
    Fq_core_shell_bicelle (q, &F1, &F2, trace_radius, trace_thick_rim, trace_thick_face, trace_length, sld_core, sld_face, sld_rim, sld_solvent);
    Iq_out = F2;

    float vol;
    vol = 1;

    // Scale by 1.0E2 [SasView: 1/cm  ->   McXtrace: 1/m]
    Iq_out = model_scale * Iq_out / vol * 1.0E2;

    p *= l_full * solid_angle / (4 * PI) * Iq_out * exp (-my_a_k * (l + l1));

    SCATTER;
  }
%}

MCDISPLAY
%{

  if (shape == 0) { /* cylinder */
    circle ("xz", 0, yheight / 2.0, 0, R);
    circle ("xz", 0, -yheight / 2.0, 0, R);
    line (-R, -yheight / 2.0, 0, -R, +yheight / 2.0, 0);
    line (+R, -yheight / 2.0, 0, +R, +yheight / 2.0, 0);
    line (0, -yheight / 2.0, -R, 0, +yheight / 2.0, -R);
    line (0, -yheight / 2.0, +R, 0, +yheight / 2.0, +R);
  } else if (shape == 1) { /* box */
    double xmin = -0.5 * xwidth;
    double xmax = 0.5 * xwidth;
    double ymin = -0.5 * yheight;
    double ymax = 0.5 * yheight;
    double zmin = -0.5 * zdepth;
    double zmax = 0.5 * zdepth;
    multiline (5, xmin, ymin, zmin, xmax, ymin, zmin, xmax, ymax, zmin, xmin, ymax, zmin, xmin, ymin, zmin);
    multiline (5, xmin, ymin, zmax, xmax, ymin, zmax, xmax, ymax, zmax, xmin, ymax, zmax, xmin, ymin, zmax);
    line (xmin, ymin, zmin, xmin, ymin, zmax);
    line (xmax, ymin, zmin, xmax, ymin, zmax);
    line (xmin, ymax, zmin, xmin, ymax, zmax);
    line (xmax, ymax, zmin, xmax, ymax, zmax);
  } else if (shape == 2) { /* sphere */
    circle ("xy", 0, 0.0, 0, R);
    circle ("xz", 0, 0.0, 0, R);
    circle ("yz", 0, 0.0, 0, R);
  }
%}
END