1 | real form_volume(real radius, real length); |
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2 | real Iq(real q, real sld, real solvent_sld, real radius, real length); |
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3 | real Iqxy(real qx, real qy, real sld, real solvent_sld, |
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4 | real radius, real length, real theta, real phi); |
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5 | |
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6 | // twovd = 2 * volume * delta_rho |
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7 | // besarg = q * R * sin(alpha) |
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8 | // siarg = q * L/2 * cos(alpha) |
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9 | real _cyl(real twovd, real besarg, real siarg); |
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10 | real _cyl(real twovd, real besarg, real siarg) |
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11 | { |
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12 | const real bj = (besarg == REAL(0.0) ? REAL(0.5) : J1(besarg)/besarg); |
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13 | const real si = (siarg == REAL(0.0) ? REAL(1.0) : sin(siarg)/siarg); |
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14 | return twovd*si*bj; |
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15 | } |
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16 | |
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17 | real form_volume(real radius, real length) |
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18 | { |
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19 | return M_PI*radius*radius*length; |
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20 | } |
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21 | |
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22 | real Iq(real q, |
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23 | real sld, |
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24 | real solvent_sld, |
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25 | real radius, |
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26 | real length) |
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27 | { |
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28 | const real qr = q*radius; |
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29 | const real qh = q*REAL(0.5)*length; |
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30 | const real twovd = REAL(2.0)*(sld-solvent_sld)*form_volume(radius, length); |
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31 | real total = REAL(0.0); |
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32 | // real lower=0, upper=M_PI_2; |
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33 | for (int i=0; i<76 ;i++) { |
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34 | // translate a point in [-1,1] to a point in [lower,upper] |
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35 | //const real alpha = ( Gauss76Z[i]*(upper-lower) + upper + lower )/2.0; |
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36 | const real alpha = REAL(0.5)*(Gauss76Z[i]*M_PI_2 + M_PI_2); |
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37 | real sn, cn; |
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38 | SINCOS(alpha, sn, cn); |
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39 | const real fq = _cyl(twovd, qr*sn, qh*cn); |
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40 | total += Gauss76Wt[i] * fq * fq * sn; |
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41 | } |
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42 | // translate dx in [-1,1] to dx in [lower,upper] |
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43 | //const real form = (upper-lower)/2.0*total; |
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44 | return REAL(1.0e-4) * total * M_PI_4; |
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45 | } |
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46 | |
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47 | |
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48 | real Iqxy(real qx, real qy, |
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49 | real sld, |
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50 | real solvent_sld, |
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51 | real radius, |
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52 | real length, |
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53 | real theta, |
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54 | real phi) |
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55 | { |
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56 | // TODO: check that radius<0 and length<0 give zero scattering. |
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57 | // This should be the case since the polydispersity weight vector should |
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58 | // be zero length, and this function never called. |
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59 | real sn, cn; // slots to hold sincos function output |
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60 | |
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61 | // Compute angle alpha between q and the cylinder axis |
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62 | SINCOS(theta*M_PI_180, sn, cn); |
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63 | const real q = sqrt(qx*qx+qy*qy); |
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64 | const real cos_val = cn*cos(phi*M_PI_180)*(qx/q) + sn*(qy/q); |
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65 | const real alpha = acos(cos_val); |
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66 | |
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67 | const real twovd = REAL(2.0)*(sld-solvent_sld)*form_volume(radius, length); |
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68 | SINCOS(alpha, sn, cn); |
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69 | const real fq = _cyl(twovd, q*radius*sn, q*REAL(0.5)*length*cn); |
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70 | return REAL(1.0e-4) * fq * fq; |
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71 | } |
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