Terminate called after throwing an instance of 'std::runtime_error' when I use a external source

User Support
1

Dear Users and Professors,
when I use a Filesource written myself, it teminate as " terminate called after throwing an instance of ‘std::runtime_error’ ", as in follow pictures.

9f0210dc5d5febef98f3173ecab182e
9f0210dc5d5febef98f3173ecab182e2437×1280 324 KB

2

The error was:
RuntimeError: Did not sample any nuclide during collision.
I give a constraints in Energy: constriants={‘energy_bounds’:[0, 10e6]}, however it did not work.

3 
int sample_nuclide(Particle& p)
{
  // Sample cumulative distribution function
  double cutoff = prn(p.current_seed()) * p.macro_xs().total;

  // Get pointers to nuclide/density arrays
  const auto& mat {model::materials[p.material()]};
  int n = mat->nuclide_.size();

  double prob = 0.0;
  for (int i = 0; i < n; ++i) {
    // Get atom density
    int i_nuclide = mat->nuclide_[i];
    double atom_density = mat->atom_density_[i];

    // Increment probability to compare to cutoff
    prob += atom_density * p.neutron_xs(i_nuclide).total;
    if (prob >= cutoff)
      return i_nuclide;
  }

  // If we reach here, no nuclide was sampled
  p.write_restart();
  throw std::runtime_error {"Did not sample any nuclide during collision."};
}

Just trying to track down from where the error is happening. when that sample_nuclide() method is called it finds a nuclide with in any material (given that your material has multiple nuclides) for collision sampling. The thing is prob += atom_density * p.neutron_xs(i_nuclide).total; is not crossing the cut_off value. I guess the main reason is p.neutron_xs(i_nuclide) maybe getting a zero value. So the main problem might be cross section data.

Try to look if that thing is set correctly. Or maybe try to run the simulation using a different seed (this one is just my wild guess)

Sorry if that doesn’t help.

4

Thanks a lot, I will try. :blush: