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Fixing an incorrect computation of CDF of bremsstrahlung photons (#3396)

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Co-authored-by: Paul Romano <paul.k.romano@gmail.com>
This commit is contained in:
GuySten 2025-05-06 03:04:47 +03:00 • committed by GitHub
parent e4f55a57b6
commit f9dca9a458
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GPG key ID: B5690EEEBB952194
5 changed files with 49 additions and 48 deletions
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9
src/material.cpp
View file

@ -777,14 +777,15 @@ void Material::init_bremsstrahlung()
// Loop over photon energies
double c = 0.0;
for (int i = 0; i < j; ++i) {
// Integrate the CDF from the PDF using the trapezoidal rule in log-log
// space
// Integrate the CDF from the PDF using the fact that the PDF is linear
// in log-log space
double w_l = std::log(data::ttb_e_grid(i));
double w_r = std::log(data::ttb_e_grid(i + 1));
double x_l = std::log(ttb->pdf(j, i));
double x_r = std::log(ttb->pdf(j, i + 1));
c += 0.5 * (w_r - w_l) * (std::exp(w_l + x_l) + std::exp(w_r + x_r));
double beta = (x_r - x_l) / (w_r - w_l);
double a = beta + 1.0;
c += std::exp(w_l + x_l) / a * std::expm1(a * (w_r - w_l));
ttb->cdf(j, i + 1) = c;
}

24
tests/regression_tests/photon_production/results_true.dat
View file

@ -16,12 +16,12 @@ tally 2:
1.573004E+00
4.296434E-04
1.845934E-07
2.350021E-01
5.522600E-02
2.350047E-01
5.522722E-02
0.000000E+00
0.000000E+00
2.350021E-01
5.522600E-02
2.350047E-01
5.522722E-02
0.000000E+00
0.000000E+00
0.000000E+00
@ -73,8 +73,8 @@ tally 3:
0.000000E+00
0.000000E+00
0.000000E+00
1.774451E+05
3.148675E+10
1.774484E+05
3.148794E+10
0.000000E+00
0.000000E+00
0.000000E+00
@ -85,8 +85,8 @@ tally 3:
0.000000E+00
0.000000E+00
0.000000E+00
7.691658E+03
5.916160E+07
7.692488E+03
5.917437E+07
0.000000E+00
0.000000E+00
tally 4:
@ -122,8 +122,8 @@ tally 4:
0.000000E+00
0.000000E+00
0.000000E+00
1.774451E+05
3.148675E+10
1.774484E+05
3.148794E+10
0.000000E+00
0.000000E+00
0.000000E+00
@ -134,7 +134,7 @@ tally 4:
0.000000E+00
0.000000E+00
0.000000E+00
7.691658E+03
5.916160E+07
7.692488E+03
5.917437E+07
0.000000E+00
0.000000E+00

58
tests/regression_tests/photon_production_fission/results_true.dat
View file

@ -1,12 +1,12 @@
k-combined:
2.270911E+00 4.568134E-02
2.278476E+00 6.220292E-02
tally 1:
2.663476E+00
2.366726E+00
2.664071E+00
2.369250E+00
0.000000E+00
0.000000E+00
2.663476E+00
2.366726E+00
2.664071E+00
2.369250E+00
0.000000E+00
0.000000E+00
0.000000E+00
@ -18,52 +18,52 @@ tally 1:
0.000000E+00
0.000000E+00
tally 2:
2.636709E+00
2.318646E+00
4.230052E+08
5.967879E+16
2.640755E+00
2.326201E+00
4.245217E+08
6.012128E+16
0.000000E+00
0.000000E+00
2.636709E+00
2.318646E+00
4.230052E+08
5.967879E+16
2.640755E+00
2.326201E+00
4.245217E+08
6.012128E+16
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
2.455009E+06
2.015314E+12
2.479234E+06
2.052367E+12
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
2.455009E+06
2.015314E+12
2.479234E+06
2.052367E+12
0.000000E+00
0.000000E+00
tally 3:
2.660004E+00
2.358564E+00
4.230052E+08
5.967879E+16
2.657846E+00
2.354717E+00
4.245217E+08
6.012128E+16
0.000000E+00
0.000000E+00
2.660004E+00
2.358564E+00
4.230052E+08
5.967879E+16
2.657846E+00
2.354717E+00
4.245217E+08
6.012128E+16
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
2.455009E+06
2.015314E+12
2.479234E+06
2.052367E+12
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
2.455009E+06
2.015314E+12
2.479234E+06
2.052367E+12
0.000000E+00
0.000000E+00

4
tests/regression_tests/photon_source/results_true.dat
View file

@ -1,5 +1,5 @@
tally 1:
2.263938E+02
5.125417E+04
2.263761E+02
5.124615E+04
0.000000E+00
0.000000E+00

2
tests/regression_tests/weightwindows/results_true.dat
View file

@ -1 +1 @@
952c20fefac374d3b9fd28627fda7d5ae262f8cd7c01a33f0381526204a2287c18e56259a599dc6fdc1b59a2d2866fdfeedea371154c8fa7a69dc5c445b08c2d
a5880ad9262e8aba90801783891ee74618144101401f06fb46e954e851a3c517ab28d5f0d6e1b2b364844f08d363cba35ab23b63fc81012ea8a6a328755d56c4