[dc02af0] | 1 | /* LamellarCailleHG kernel - allows for name changes of passed parameters ... |
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| 2 | Maths identical to LamellarCaille apart from the line for P(Q) |
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| 3 | */ |
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| 4 | |
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[abb6e4f] | 5 | static double |
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| 6 | Iq(double qval, |
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| 7 | double length_tail, |
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| 8 | double length_head, |
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| 9 | double fp_Nlayers, |
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| 10 | double dd, |
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| 11 | double Cp, |
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| 12 | double tail_sld, |
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| 13 | double head_sld, |
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| 14 | double solvent_sld) |
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[dc02af0] | 15 | { |
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[abb6e4f] | 16 | int Nlayers = (int)(fp_Nlayers+0.5); //cast to an integer for the loop |
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[dc02af0] | 17 | double inten,Pq,Sq,alpha,temp,t2; |
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| 18 | //double dQ, dQDefault, t1, t3; |
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| 19 | // from wikipedia 0.577215664901532860606512090082402431042159335 |
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| 20 | const double Euler = 0.577215664901533; // Euler's constant, increased sig figs for new models Feb 2015 |
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| 21 | //dQDefault = 0.0; //[=] 1/A, q-resolution, default value |
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| 22 | //dQ = dQDefault; // REMOVED UNUSED dQ calculations for new models Feb 2015 |
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| 23 | |
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[abb6e4f] | 24 | Pq = (head_sld-solvent_sld)*(sin(qval*(length_head+length_tail))-sin(qval*length_tail)) |
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| 25 | + (tail_sld-solvent_sld)*sin(qval*length_tail); |
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[cd55ac3] | 26 | Pq *= Pq; |
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| 27 | Pq *= 4.0/(qval*qval); |
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[dc02af0] | 28 | |
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| 29 | Sq = 0.0; |
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[1c6286d] | 30 | for(int ii=1; ii < Nlayers; ii++) { |
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[dc02af0] | 31 | temp = 0.0; |
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| 32 | alpha = Cp/4.0/M_PI/M_PI*(log(M_PI*ii) + Euler); |
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| 33 | //t1 = 2.0*dQ*dQ*dd*dd*alpha; |
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| 34 | t2 = 2.0*qval*qval*dd*dd*alpha; |
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| 35 | //t3 = dQ*dQ*dd*dd*ii*ii; |
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| 36 | |
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[abb6e4f] | 37 | temp = 1.0-(double)ii/(double)Nlayers; |
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[dc02af0] | 38 | //temp *= cos(dd*qval*ii/(1.0+t1)); |
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| 39 | temp *= cos(dd*qval*ii); |
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[95e861b] | 40 | //if (temp < 0) printf("q=%g: ii=%d, cos(dd*q*ii)=cos(%g) < 0\n",qval,ii,dd*qval*ii); |
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[dc02af0] | 41 | //temp *= exp(-1.0*(t2 + t3)/(2.0*(1.0+t1)) ); |
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[1c6286d] | 42 | temp *= exp(-t2/2.0); |
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[dc02af0] | 43 | //temp /= sqrt(1.0+t1); |
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| 44 | |
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| 45 | Sq += temp; |
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| 46 | } |
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| 47 | |
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| 48 | Sq *= 2.0; |
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| 49 | Sq += 1.0; |
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| 50 | |
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[12c810f] | 51 | //if (Sq < 0) printf("q=%g: S(q) =%g\n", qval, Sq); |
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| 52 | |
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[dc02af0] | 53 | inten = 2.0*M_PI*Pq*Sq/(dd*qval*qval); |
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| 54 | |
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| 55 | inten *= 1.0e-04; // 1/A to 1/cm |
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[abb6e4f] | 56 | return inten; |
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[dc02af0] | 57 | } |
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| 58 | |
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