1 | /** |
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2 | This software was developed by the University of Tennessee as part of the |
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3 | Distributed Data Analysis of Neutron Scattering Experiments (DANSE) |
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4 | project funded by the US National Science Foundation. |
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5 | |
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6 | If you use DANSE applications to do scientific research that leads to |
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7 | publication, we ask that you acknowledge the use of the software with the |
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8 | following sentence: |
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9 | |
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10 | "This work benefited from DANSE software developed under NSF award DMR-0520547." |
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11 | |
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12 | copyright 2008, University of Tennessee |
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13 | */ |
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14 | |
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15 | /** |
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16 | * Scattering model classes |
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17 | * The classes use the IGOR library found in |
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18 | * sansmodels/src/libigor |
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19 | * |
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20 | */ |
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21 | |
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22 | #include <math.h> |
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23 | #include "parameters.hh" |
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24 | #include <stdio.h> |
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25 | using namespace std; |
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26 | #include "lamellar.h" |
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27 | |
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28 | /* LamellarFFX : calculates the form factor of a lamellar structure - no S(q) effects included |
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29 | -NO polydispersion included |
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30 | */ |
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31 | static double lamellar_kernel(double dp[], double q){ |
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32 | double scale,del,sld_bi,sld_sol,contr,bkg; //local variables of coefficient wave |
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33 | double inten, qval,Pq; |
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34 | double Pi; |
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35 | |
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36 | |
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37 | Pi = 4.0*atan(1.0); |
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38 | scale = dp[0]; |
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39 | del = dp[1]; |
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40 | sld_bi = dp[2]; |
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41 | sld_sol = dp[3]; |
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42 | bkg = dp[4]; |
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43 | qval = q; |
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44 | contr = sld_bi -sld_sol; |
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45 | |
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46 | Pq = 2.0*contr*contr/qval/qval*(1.0-cos(qval*del)); |
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47 | |
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48 | inten = 2.0*Pi*scale*Pq/(qval*qval); //this is now dimensionless... |
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49 | |
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50 | inten /= del; //normalize by the thickness (in A) |
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51 | |
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52 | inten *= 1.0e8; // 1/A to 1/cm |
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53 | |
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54 | return(inten+bkg); |
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55 | } |
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56 | |
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57 | LamellarModel :: LamellarModel() { |
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58 | scale = Parameter(1.0); |
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59 | bi_thick = Parameter(50.0, true); |
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60 | bi_thick.set_min(0.0); |
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61 | sld_bi = Parameter(1.0e-6); |
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62 | sld_sol = Parameter(6.3e-6); |
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63 | background = Parameter(0.0); |
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64 | } |
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65 | |
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66 | /** |
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67 | * Function to evaluate 1D scattering function |
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68 | * The NIST IGOR library is used for the actual calculation. |
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69 | * @param q: q-value |
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70 | * @return: function value |
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71 | */ |
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72 | double LamellarModel :: operator()(double q) { |
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73 | double dp[5]; |
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74 | |
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75 | // Fill parameter array for IGOR library |
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76 | // Add the background after averaging |
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77 | dp[0] = scale(); |
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78 | dp[1] = bi_thick(); |
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79 | dp[2] = sld_bi(); |
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80 | dp[3] = sld_sol(); |
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81 | dp[4] = 0.0; |
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82 | |
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83 | // Get the dispersion points for the bi_thick |
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84 | vector<WeightPoint> weights_bi_thick; |
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85 | bi_thick.get_weights(weights_bi_thick); |
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86 | // Perform the computation, with all weight points |
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87 | double sum = 0.0; |
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88 | double norm = 0.0; |
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89 | |
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90 | // Loop over short_edgeA weight points |
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91 | for(int i=0; i< (int)weights_bi_thick.size(); i++) { |
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92 | dp[1] = weights_bi_thick[i].value; |
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93 | |
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94 | sum += weights_bi_thick[i].weight * lamellar_kernel(dp, q); |
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95 | norm += weights_bi_thick[i].weight; |
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96 | |
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97 | } |
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98 | |
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99 | return sum/norm + background(); |
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100 | } |
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101 | |
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102 | /** |
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103 | * Function to evaluate 2D scattering function |
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104 | * @param q_x: value of Q along x |
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105 | * @param q_y: value of Q along y |
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106 | * @return: function value |
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107 | */ |
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108 | |
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109 | double LamellarModel :: operator()(double qx, double qy) { |
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110 | double q = sqrt(qx*qx + qy*qy); |
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111 | return (*this).operator()(q); |
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112 | } |
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113 | |
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114 | /** |
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115 | * Function to evaluate 2D scattering function |
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116 | * @param pars: parameters of the lamellar |
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117 | * @param q: q-value |
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118 | * @param phi: angle phi |
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119 | * @return: function value |
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120 | */ |
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121 | double LamellarModel :: evaluate_rphi(double q, double phi) { |
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122 | return (*this).operator()(q); |
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123 | } |
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124 | /** |
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125 | * Function to calculate effective radius |
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126 | * @return: effective radius value |
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127 | */ |
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128 | double LamellarModel :: calculate_ER() { |
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129 | //NOT implemented yet!!! |
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130 | return 0.0; |
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131 | } |
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132 | double LamellarModel :: calculate_VR() { |
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133 | return 1.0; |
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134 | } |
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