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Xtensor for photoelectric cross sections matches the flux spectrum for uranium of the previous iteration of OpenMC

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This commit is contained in:
myerspat 2022-06-09 09:52:50 -05:00
parent 6df0286b2e
commit 61db44f40e
2 changed files with 20 additions and 17 deletions
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15
src/photon.cpp
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@ -128,7 +128,7 @@ PhotonInteraction::PhotonInteraction(hid_t group)
}
shells_.resize(n_shell);
cross_sections_.resize({energy_.size(), n_shell});
cross_sections_ = xt::zeros<double>({energy_.size(), n_shell});
// Create mapping from designator to index
std::unordered_map<int, int> shell_map;
@ -166,8 +166,8 @@ PhotonInteraction::PhotonInteraction(hid_t group)
read_dataset(tgroup, "xs", xs);
auto cross_section = xt::view(cross_sections_,
xt::range(shell.threshold, shell.threshold + xs.size()), i);
cross_section = xt::where(xs > 0.0, xt::log(xs), -500.0);
xt::range(shell.threshold, xt::placeholders::_), i);
cross_section = xt::where(xs > 0, xt::log(xs), 0);
if (object_exists(tgroup, "transitions")) {
// Determine dimensions of transitions
@ -571,10 +571,13 @@ void PhotonInteraction::calculate_xs(Particle& p) const
incoherent_(i_grid) + f * (incoherent_(i_grid + 1) - incoherent_(i_grid)));
// Calculate microscopic photoelectric cross section
const auto& xs_upper = xt::row(cross_sections_, i_grid);
const auto& xs_lower = xt::row(cross_sections_, i_grid + 1);
xs.photoelectric = 0.0;
const auto& xs_lower = xt::row(cross_sections_, i_grid);
const auto& xs_upper = xt::row(cross_sections_, i_grid + 1);
xs.photoelectric = xt::sum(xt::exp(xs_upper + f * (xs_upper - xs_lower)))[0];
for (int i = 0; i < xs_upper.size(); ++i)
if (xs_lower(i) != 0)
xs.photoelectric += std::exp(xs_lower(i) + f * (xs_upper(i) - xs_lower(i)));
// Calculate microscopic pair production cross section
xs.pair_production = std::exp(

22
src/physics.cpp
View file

@ -29,6 +29,7 @@
#include <algorithm> // for max, min, max_element
#include <cmath> // for sqrt, exp, log, abs, copysign
#include <xtensor/xview.hpp>
namespace openmc {
@ -344,25 +345,24 @@ void sample_photon_reaction(Particle& p)
// Photoelectric effect
double prob_after = prob + micro.photoelectric;
int i_grid = micro.index_grid;
double f = micro.interp_factor;
const auto& xs_lower = xt::row(element.cross_sections_, i_grid);
const auto& xs_upper = xt::row(element.cross_sections_, i_grid + 1);
if (prob_after > cutoff) {
for (int i_shell = 0; i_shell < element.shells_.size(); ++i_shell) {
const auto& shell {element.shells_[i_shell]};
// Get grid index and interpolation factor
int i_grid = micro.index_grid;
double f = micro.interp_factor;
// Check threshold of reaction
int i_start = shell.threshold;
if (i_grid < i_start)
if (xs_lower(i_shell) == 0)
continue;
// Evaluation subshell photoionization cross section
double xs = std::exp(element.cross_sections_(i_grid - i_start) +
f * (element.cross_sections_(i_grid + 1 - i_start) -
element.cross_sections_(i_grid - i_start)));
// Evaluation subshell photoionization cross section
prob += std::exp(xs_lower(i_shell) +
f * (xs_upper(i_shell) -
xs_lower(i_shell)));
prob += xs;
if (prob > cutoff) {
double E_electron = p.E() - shell.binding_energy;