Note that there are different versions around. See also dmp2nemo, written before this version was known.
    1. dmpindx,date,ndim,eqnindx,version,gamma,poly,lsfm    (64 bytes)
    2. tframe,n1,n2 (16 bytes)
    3. class(n0)        ** Key **
    4. state(n0)        
    5. mass(n0)            ** Mass **
    6. x(n0)            ** PhaseSpace **
    7. y(n0)
    8. z(n0)
    9. vx(n0)
    10. vy(n0)
    11. vz(n0)
        
        12. eps(n0)    : dmpindx > 1
        13. phi(n0)            ** Potential **
        14. ax(n0)            ** Acc **
        15. ay(n0)
        16. az(n0)
        17.    smft(n0)    [only if lsfm is TRUE)
        18.    smfz(n0)    [only if lsfm is TRUE)
        19. u(n2)      : dmpindx > 2 && n2 > 0
        20. d(n2)
        21. divv(n2)
        22. udot1(n2)
        23. udot2(n2)
        24. udot3(n2)        [only in version 2]
        25. udot4(n2)        [only in version 2]
        26. h(n2)
        27. wgtmol(n2)        [only in version 2]
        28. frcneu(n2)        [only in version 2]
        29. tau(n2)        [only in version 2]
src/nbody/io hellersnap.c
26-jun-98 V1.0 Created, for version=1 NEMO 23-may-01 V2.0 included new options, for version=2 PJT