hepmc_status.hpp

Go to the documentation of this file.

// SPDX-FileCopyrightText: 2026 CERN for the benefit of the SHiP Collaboration
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
// hepmc_status.hpp — HepMC generator status codes
//
// SHiP::MCParticle::status carries the HepMC status code (the conventions
// agreed in February 2009), as produced by Pythia8's Particle::statusHepMC()
// and used by EDM4hep for its generatorStatus. Geant4's own HepMC example
// uses the same status == 1 predicate to decide what to track.
//
// Deliberately free of includes so the Pythia8 benchmark's stand-in particle
// struct can use it without pulling in the data model.
 
#pragma once
 
namespace aegir::hepmc {
 
inline constexpr int empty = 0;          
inline constexpr int final_state = 1;    
inline constexpr int decayed = 2;        
inline constexpr int documentation = 3;  
inline constexpr int beam = 4;           
// 11-200 are intermediate entries with a generator-dependent classification.
inline constexpr int intermediate_min = 11;
inline constexpr int intermediate_max = 200;
 
[[nodiscard]] constexpr bool is_final_state(int status) noexcept {
  return status == final_state;
}
 
static_assert(is_final_state(final_state));
static_assert(!is_final_state(empty));
static_assert(!is_final_state(decayed));
static_assert(!is_final_state(documentation));
static_assert(!is_final_state(beam));
static_assert(!is_final_state(intermediate_min));
 
}  // namespace aegir::hepmc