5. Particle Restart File Format

The current version of the particle restart file format is 2.0.


  • filetype (char[]) – String indicating the type of file.
  • version (int[2]) – Major and minor version of the particle restart file format.
  • openmc_version (int[3]) – Major, minor, and release version number for OpenMC.
  • git_sha1 (char[40]) – Git commit SHA-1 hash.
  • current_batch (int) – The number of batches already simulated.
  • generations_per_batch (int) – Number of generations per batch.
  • current_generation (int) – The number of generations already simulated.
  • n_particles (int8_t) – Number of particles used per generation.
  • run_mode (char[]) – Run mode used, either ‘fixed source’, ‘eigenvalue’, or ‘particle restart’.
  • id (int8_t) – Unique identifier of the particle.
  • weight (double) – Weight of the particle.
  • energy (double) – Energy of the particle in eV for continuous-energy mode, or the energy group of the particle for multi-group mode.
  • xyz (double[3]) – Position of the particle.
  • uvw (double[3]) – Direction of the particle.