source: sasview/sansmodels/src/sans/models/c_extensions/sld_cal.c @ a807ffd

/**
 * SLD Calculator
 * @author: Jae Hie Cho / UTK
 */

#include "sld_cal.h"
#include "libmultifunc/librefl.h"
#include <math.h>


/**
 * Function to calculate sld
 * @param pars: parameters
 * @param x: independent param-value
 * @return: sld value
 */
double sld_cal_analytical_1D(SLDCalParameters *pars, double x) {
        double fun, nsl, n_s, fun_coef, sld_l, sld_r, sld_out;
        int fun_type;

        fun = pars->fun_type;
        nsl = pars->npts_inter;
        n_s = pars->shell_num;
        fun_coef = pars->nu_inter;
        sld_l = pars-> sld_left;
        sld_r = pars-> sld_right;

        fun_type = floor(fun);

        sld_out = intersldfunc(fun_type, nsl, n_s, fun_coef, sld_l, sld_r);

        return sld_out;
}

/**
 * Function to evaluate 2D scattering function
 * @param pars: parameters
 * @param q: q-value
 * @return: function value
 */
double sld_cal_analytical_2D(SLDCalParameters *pars, double x, double phi) {
        return sld_cal_analytical_1D(pars,x);
}

double sld_cal_analytical_2DXY(SLDCalParameters *pars, double xx, double xy){
        return sld_cal_analytical_1D(pars,sqrt(xx*xx+xy*xy));
}