*
*=== Flkstk ===========================================================*
*
*----------------------------------------------------------------------*
*                                                                      *
*     Partial (some variables come from FLUKA87)                       *
*     Copyright (C) 2003-2019:  CERN & INFN                            *
*     All Rights Reserved.                                             *
*                                                                      *
*     FLUKA90-20xy particle stack:                                     *
*                                                                      *
*     /Flkstk/ stack for the primaries                                 *
*        Wtflk  = particle statistical weight                          *
*        Pmoflk = particle (laboratory) momentum (GeV/c)               *
*        Tkeflk = particle (laboratory) kinetic energy (GeV)           *
*        Xflk   = particle position  x-coordinate                      *
*        Yflk   = particle position  y-coordinate                      *
*        Zflk   = particle position  z-coordinate                      *
*        Txflk  = particle direction x-coordinate                      *
*        Tyflk  = particle direction y-coordinate                      *
*        Tzflk  = particle direction z-coordinate                      *
*        Txpol  = x direction cosine of the particle polarization      *
*        Typol  = y direction cosine of the particle polarization      *
*        Tzpol  = z direction cosine of the particle polarization      *
*        Txnor  = x direction cosine of a (possible) surface normal    *
*        Tynor  = y direction cosine of a (possible) surface normal    *
*        Tznor  = z direction cosine of a (possible) surface normal    *
*        Dfnear = distance to the nearest boundary                     *
*        Agestk = age of the particle (seconds)                        *
*        Ekpstk = kinetic energy of the last inelastic interaction     *
*                 parent                                               *
*        Aknshr = Kshort component of K0/K0bar                         *
*        Frcphn = cross section for force photonuclear interaction (if *
*                 < 0), distance to a forced photonuclear interaction  *
*                (if > 0)                                              *
*        Lfrphn = flag for forced photonuclear interaction             *
*        Raddly = delay (s) in production wrt the nominal primary "0"  *
*                 time for particle produced in radioactive decays     *
*                (i.e. those coming from decays of daughter isotopes), *
*                 when in analogue mode, flag for position in the      *
*                 activr array when in non-analogue mode               *
*        Cmpath = cumulative path travelled by the particle since it   *
*                 was produced (cm)                                    *
*        Ecrflk = Transverse energy for channeled particles            *
*        Anfstk = extra infos: for EM particles a non zero value is    *
*                 the kinetic energy a possible delta ray parent       *
*                 (excluding Moller and Bhabha)                        *
*        Sparek = spare real variables available for the users         *
*        Ispark = spare integer variables available for the users      *
*        Iloflk = particle identity (Paprop numbering)                 *
*        Igroup = energy group for low energy neutrons                 *
*                 if |Igroup| >= 100000, Sign(|Igroup|-10000,Igroup)   *
*                 is the current charge of the ion under consideration *
*        Iprstk = (Paprop) id of the last inelastic interaction parent *
*        Infstk = extra infos: for EM particles a non zero value is    *
*                 the (coded) id of a possible delta ray parent        *
*                 (excluding Moller and Bhabha)                        *
*        Lnfstk = extra infos: for EM particles a non zero value is    *
*                 the generation of a possible delta ray parent        *
*                 (excluding Moller and Bhabha)                        *
*        Loflk  = particle generation                                  *
*        Louse  = user flag                                            *
*        Nrgflk = particle region number                               *
*        Nlattc = particle lattice cell number                         *
*        Nhspnt = pointer to the history object (Geant4 geometry)      *
*        Nevent = number of the event which created the particle       *
*        Numpar = particle number                                      *
*        Irdazm = id of the parent radioactive isotope if any          *
*                 Irdazm = A + 1000 Z + 1000000 m                      *
*        Lraddc = flag for particles generated in radioactive decays   *
*        Kchflk = flag for channeled particle                          *
*        Nparma = largest particle number ever reached                 *
*        Nstmax = highest value of the stack pointer ever reached      *
*                 in the run                                           *
*        Npflka = Fluka stack pointer                                  *
*        Nstaol = stack pointer of the last processed particle         *
*        Igroun = energy group number of the last processed particle   *
*                 if it is a low energy neutron                        *
*                                                                      *
*----------------------------------------------------------------------*
*
      LOGICAL LRADDC, LFRPHN, LCHFLK
      INTEGER*8 NLATTC, NHSPNT
      COMMON / FLKSTK /
     &          XFLK   (0:MFSTCK), YFLK   (0:MFSTCK), ZFLK   (0:MFSTCK),
     &          TXFLK  (0:MFSTCK), TYFLK  (0:MFSTCK), TZFLK  (0:MFSTCK),
     &          TXPOL  (0:MFSTCK), TYPOL  (0:MFSTCK), TZPOL  (0:MFSTCK),
     &          TXNOR  (0:MFSTCK), TYNOR  (0:MFSTCK), TZNOR  (0:MFSTCK),
     &          WTFLK  (0:MFSTCK), PMOFLK (0:MFSTCK), TKEFLK (0:MFSTCK),
     &          DFNEAR (0:MFSTCK), AGESTK (0:MFSTCK), AKNSHR (0:MFSTCK),
     &          RADDLY (0:MFSTCK), CMPATH (0:MFSTCK), FRCPHN (0:MFSTCK),
     &          ECRFLK (0:MFSTCK), ANFSTK (0:MFSTCK), EKPSTK (0:MFSTCK),
     &          SPAREK (MKBMX1,0:MFSTCK),             NLATTC (0:MFSTCK),
     &          NHSPNT (0:MFSTCK),             ISPARK (MKBMX2,0:MFSTCK),
     &          INFSTK (0:MFSTCK), LNFSTK (0:MFSTCK), ILOFLK (0:MFSTCK),
     &          IGROUP (0:MFSTCK), IPRSTK (0:MFSTCK), KCHFLK (0:MFSTCK),
     &          LOFLK  (0:MFSTCK), LOUSE  (0:MFSTCK), NRGFLK (0:MFSTCK), 
     &          NEVENT (0:MFSTCK), NUMPAR (0:MFSTCK),
     &          IRDAZM (0:MFSTCK), LRADDC (0:MFSTCK), LFRPHN (0:MFSTCK),
     &          NPARMA, NSTMAX, NPFLKA, NSTAOL, IGROUN
*  added for back-compatibility
      DIMENSION LCHFLK (0:MFSTCK), DCHFLK (0:MFSTCK)
      EQUIVALENCE ( LCHFLK (0), KCHFLK (0) )
      EQUIVALENCE ( DCHFLK (0), ECRFLK (0) )
      SAVE / FLKSTK /