source: sasview/src/sas/models/c_extension/c_models/fractal.cpp @ fc18690

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Last change on this file since fc18690 was 79492222, checked in by krzywon, 10 years ago

Changed the file and folder names to remove all SANS references.

  • Property mode set to 100644
File size: 3.1 KB
Line 
1/**
2        This software was developed by the University of Tennessee as part of the
3        Distributed Data Analysis of Neutron Scattering Experiments (DANSE)
4        project funded by the US National Science Foundation.
5
6        If you use DANSE applications to do scientific research that leads to
7        publication, we ask that you acknowledge the use of the software with the
8        following sentence:
9
10        "This work benefited from DANSE software developed under NSF award DMR-0520547."
11
12        copyright 2008, University of Tennessee
13 */
14
15/**
16 * Scattering model classes
17 * The classes use the IGOR library found in
18 *   sansmodels/src/libigor
19 *
20 */
21
22#include <math.h>
23#include "parameters.hh"
24#include <stdio.h>
25using namespace std;
26#include "fractal.h"
27
28extern "C" {
29#include "libTwoPhase.h"
30}
31
32FractalModel :: FractalModel() {
33  scale      = Parameter(1.0);
34  radius = Parameter(5.0, true);
35  radius.set_min(0.0);
36  fractal_dim = Parameter(2.0);
37  cor_length = Parameter(100.0);
38  sldBlock = Parameter(2.0e-6);
39  sldSolv= Parameter(6.35e-6);
40  background = Parameter(0.0);
41}
42
43/**
44 * Function to evaluate 1D scattering function
45 * The NIST IGOR library is used for the actual calculation.
46 * @param q: q-value
47 * @return: function value
48 */
49double FractalModel :: operator()(double q) {
50  double dp[7];
51
52  // Fill parameter array for IGOR library
53  // Add the background after averaging
54  dp[0] = scale();
55  dp[1] = radius();
56  dp[2] = fractal_dim();
57  dp[3] = cor_length();
58  dp[4] = sldBlock();
59  dp[5] = sldSolv();
60  dp[6] = 0.0;
61
62  // Get the dispersion points for the radius
63  vector<WeightPoint> weights_rad;
64  radius.get_weights(weights_rad);
65
66  // Perform the computation, with all weight points
67  double sum = 0.0;
68  double norm = 0.0;
69  double vol = 0.0;
70
71  // Loop over radius weight points
72  for(size_t i=0; i<weights_rad.size(); i++) {
73    dp[1] = weights_rad[i].value;
74
75    //Un-normalize Fractal by volume
76    sum += weights_rad[i].weight
77        * Fractal(dp, fabs(q)) * pow(weights_rad[i].value,3);
78    //Find average volume
79    vol += weights_rad[i].weight
80        * pow(weights_rad[i].value,3);
81
82    norm += weights_rad[i].weight;
83  }
84
85  if (vol != 0.0 && norm != 0.0) {
86    //Re-normalize by avg volume
87    sum = sum/(vol/norm);}
88  return sum/norm + background();
89}
90
91/**
92 * Function to evaluate 2D scattering function
93 * @param q_x: value of Q along x
94 * @param q_y: value of Q along y
95 * @return: function value
96 */
97double FractalModel :: operator()(double qx, double qy) {
98  double q = sqrt(qx*qx + qy*qy);
99  return (*this).operator()(q);
100}
101
102/**
103 * Function to evaluate 2D scattering function
104 * @param pars: parameters of the FractalModel
105 * @param q: q-value
106 * @param phi: angle phi
107 * @return: function value
108 */
109double FractalModel :: evaluate_rphi(double q, double phi) {
110  return (*this).operator()(q);
111}
112
113/**
114 * Function to calculate effective radius
115 * @return: effective radius value
116 */
117double FractalModel :: calculate_ER() {
118  //NOT implemented yet!!! 'cause None shape Model
119  return 0.0;
120}
121double FractalModel :: calculate_VR() {
122  return 1.0;
123}
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