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prevent underflow for diffuse scattering Pippard - very short mean free path

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suter_a
2013-10-21 08:57:49 +00:00
parent 2955a1d361
commit d3e14a2a47
1 changed files with 8 additions and 2 deletions
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6
src/tests/nonlocal/PPippard.cpp
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@ -486,6 +486,9 @@ Double_t PPippard::Calc_v(const Double_t s) const
if (ss < 0.001) { if (ss < 0.001) {
v = (-0.0772157-log(ss))*ss+s2; // series expansion in s up to 2nd order v = (-0.0772157-log(ss))*ss+s2; // series expansion in s up to 2nd order
} else { } else {
if (ss > 50.0)
v = 1/6.0*(exp(-ss)*(s2-ss-4.0) + 4.0);
else
v = 1/6.0*(exp(-ss)*(s2-ss-4.0) + 4.0 - ss*(s2-6.0) * gsl_sf_gamma_inc(0.0, ss)); v = 1/6.0*(exp(-ss)*(s2-ss-4.0) + 4.0 - ss*(s2-6.0) * gsl_sf_gamma_inc(0.0, ss));
} }
@ -511,6 +514,9 @@ Double_t PPippard::Calc_w(const Double_t s) const
if (ss < 0.001) { if (ss < 0.001) {
w = (0.211392 - 0.5*log(ss))*s2; // series expansion in s up to 2nd order w = (0.211392 - 0.5*log(ss))*s2; // series expansion in s up to 2nd order
} else { } else {
if (ss > 50.0)
w = 1/24.0*(exp(-ss)*(6.0-10.0*ss-s2+ss*s2)+16.0*ss-6.0);
else
w = 1/24.0*(exp(-ss)*(6.0-10.0*ss-s2+ss*s2)+16.0*ss-6.0-s2*(s2-12.0)*gsl_sf_gamma_inc(0.0, ss)); w = 1/24.0*(exp(-ss)*(6.0-10.0*ss-s2+ss*s2)+16.0*ss-6.0-s2*(s2-12.0)*gsl_sf_gamma_inc(0.0, ss));
} }