Gen_HEPEVT Node1 Gen_HEPEVT + Gen_HEPEVT() * m_NEVHEP * m_NHEP * nevhep() * nhep() * isthep() * idhep() * first_parent() * last_parent() * first_child() * last_child() and 17 more... Node2 std::map< int, std ::pair< int, int > > + keys + elements Node2->Node1 -m_JMOHEP -m_JDAHEP Node3 std::map< int, int > + keys + elements Node3->Node1 -m_ISTHEP -m_IDHEP Node4 std::map< int, double > + keys + elements Node4->Node1 -m_VHEP1 -m_VHEP2 -m_VHEP3 -m_PHEP0 -m_PHEP1 -m_PHEP2 -m_PHEP3 -m_PHEP4 -m_VHEP0