core_shell_microgelscostrafo411magnetic_modelticket-1257-vesicle-productticket_1156ticket_1265_superballticket_822_more_unit_tests
Last change
on this file since acfb094 was
925ad6e,
checked in by wojciech, 7 years ago
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sph_j1c translated to sas_3j1x_x
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-
Property mode set to
100644
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File size:
1.0 KB
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1 | #define INVALID(p) (p.fractal_dim_mass < 1.0) |
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2 | |
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3 | static double |
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4 | Iq(double q, double radius, double fractal_dim_mass, double cutoff_length) |
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5 | { |
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6 | //calculate P(q) |
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7 | const double pq = square(sas_3j1x_x(q*radius)); |
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8 | |
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9 | //calculate S(q) |
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10 | // S(q) = gamma(D-1) sin((D-1)atan(q c))/q c^(D-1) (1+(q c)^2)^(-(D-1)/2) |
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11 | // lim D->1 [gamma(D-1) sin((D-1) a)] = a |
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12 | // lim q->0 [sin((D-1) atan(q c))/q] = (D-1) c |
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13 | // lim q,D->0,1 [gamma(D-1) sin((D-1)atan(q c))/q] = c |
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14 | double sq; |
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15 | if (q > 0. && fractal_dim_mass > 1.) { |
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16 | const double Dm1 = fractal_dim_mass - 1.0; |
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17 | const double t1 = sas_gamma(Dm1)*sin(Dm1*atan(q*cutoff_length)); |
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18 | const double t2 = pow(cutoff_length, Dm1); |
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19 | const double t3 = pow(1.0 + square(q*cutoff_length), -0.5*Dm1); |
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20 | sq = t1 * t2 * t3 / q; |
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21 | } else if (q > 0.) { |
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22 | sq = atan(q*cutoff_length)/q; |
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23 | } else if (fractal_dim_mass > 1.) { |
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24 | const double D = fractal_dim_mass; |
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25 | sq = pow(cutoff_length, D) * sas_gamma(D); |
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26 | } else { |
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27 | sq = cutoff_length; |
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28 | } |
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29 | |
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30 | return pq * sq; |
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31 | } |
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