1 | #define INVALID(v) (v.radius<0 || v.length<0) |
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2 | |
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3 | static double |
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4 | form_volume(double radius, double length) |
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5 | { |
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6 | return M_PI*radius*radius*length; |
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7 | } |
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8 | |
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9 | static double |
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10 | _fq(double qab, double qc, double radius, double length) |
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11 | { |
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12 | return sas_2J1x_x(qab*radius) * sas_sinx_x(qc*0.5*length); |
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13 | } |
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14 | |
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15 | static void |
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16 | Fq(double q, |
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17 | double *F1, |
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18 | double *F2, |
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19 | double sld, |
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20 | double solvent_sld, |
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21 | double radius, |
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22 | double length) |
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23 | { |
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24 | // translate a point in [-1,1] to a point in [0, pi/2] |
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25 | const double zm = M_PI_4; |
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26 | const double zb = M_PI_4; |
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27 | |
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28 | double total_F1 = 0.0; |
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29 | double total_F2 = 0.0; |
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30 | for (int i=0; i<GAUSS_N ;i++) { |
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31 | const double theta = GAUSS_Z[i]*zm + zb; |
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32 | double sin_theta, cos_theta; // slots to hold sincos function output |
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33 | // theta (theta,phi) the projection of the cylinder on the detector plane |
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34 | SINCOS(theta , sin_theta, cos_theta); |
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35 | const double form = _fq(q*sin_theta, q*cos_theta, radius, length); |
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36 | total_F1 += GAUSS_W[i] * form * sin_theta; |
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37 | total_F2 += GAUSS_W[i] * form * form * sin_theta; |
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38 | } |
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39 | // translate dx in [-1,1] to dx in [lower,upper] |
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40 | total_F1 *= zm; |
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41 | total_F2 *= zm; |
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42 | const double s = (sld - solvent_sld) * form_volume(radius, length); |
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43 | *F1 = 1e-2 * s * total_F1; |
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44 | *F2 = 1e-4 * s * s * total_F2; |
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45 | } |
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46 | |
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47 | |
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48 | |
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49 | static double |
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50 | Iqac(double qab, double qc, |
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51 | double sld, |
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52 | double solvent_sld, |
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53 | double radius, |
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54 | double length) |
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55 | { |
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56 | const double form = _fq(qab, qc, radius, length); |
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57 | const double s = (sld-solvent_sld) * form_volume(radius, length); |
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58 | return 1.0e-4 * square(s * form); |
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59 | } |
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60 | |
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