C
C TPT - main track finding
C
C DESCRIPTION:
C Sets up corespondence between the hit id and the entry in the tphit
C table( tpt_hit_pnt), then sets up a look up tables so that hits for
C a given row & sector could be found( tpt_row_sect_pnt). Next track
C segments are found(tpt_form_segments)and extended(tpt_extend_segments)
C Final step consists of an attempt to merge reconstructed pieces of
C tracks.
C
C INPUT ARGUMENTS:
C  tpar_h    - header for the tptpar (tracking parameters) table
C  tpar     - tracking parameters table
C  pad_pl_h  - header for the pad_plane (pad_plane geometry) table
C  pad_pl   - pad_plane geometry table
C  hit_h     - header for the tphit (tpc hits) table
C  hit      - rows of the tphit table
C
C OUTPUT ARGUMENTS:
C  track_h   - header for the tptrack (reconstructed tracks) table
C  track    - rows of the tptrack table
C
C<---------------------------------------------------------------------
      INTEGER FUNCTION TPT(tpar_h,tpar,pad_pl_h,pad_pl,
     >                               hit_h,hit,track_h, track)
C
C Modified: 13-NOV-1997 by R.Bossingham
C           Eliminate unused variable.
C
      IMPLICIT NONE

#include "tpt.inc"

#include "tpt_pointers.inc"
#include "tpt_mxdim.inc"
#include "tpt_mxhit.inc"

C______________________________________________________________________

C     Local variables
      RECORD /track_pointers/ trk(mxtrack)
C
      INTEGER loc_hit(tpt_mxhit)
C             loc_hit - pointers to the tphit table sorted acc
C             to row/sec field
      INTEGER tpstart(mxrow,mxsector),tpcount(mxrow,mxsector)
C             tpstart -pointer to the first hit in the row/sector
C             tpcount -# of hits in a given row/sector
      INTEGER tls_Index_Sort_i
C            sort hits in the TPC table according to row/sec field
      INTEGER tpt_row_sect_pnt
      INTEGER tpt_form_segments
      INTEGER tpt_extend_segments
      INTEGER tpt_merge_segments
      INTEGER iret  !scratch integer
      INTEGER i,ipass
      INTEGER next_hit(tpt_mxhit),slice_loc(mxsector,mxrow,mxslic)
      INTEGER slice_pnt(2,mxsector*mxrow*mxslic),last_track
      REAL    time_now,time_all
      COMMON /CPUTIM/ time_all
      REAL    time_sort,time_seguv,time_seg,time_ext,time_merge
      real    xglobal(3), xlocal(3)
      integer tgc_global_to_local,isect
C______________________________________________________________________
C     initialize timing counters
      time_sort = 0
      time_seguv = 0
      time_seg = 0
      time_ext = 0
      time_merge = 0
      ipass=1
      if(tpar(ipass).debug(1).eq.1) then
          write(6,*) 'starting in the main tracking subroutine ...'
      endif

C     set return value to normal success
      tpt = STAFCV_OK
C     set counter for number of rows of good data to 0
      track_h.nok = 0
C     preset all the hit(i).track to 0
      do i=1,hit_h.nok
        hit(i).track=0
      end do
      if(hit_h.nok.eq.0) go to 888
c
c     make sure that there is enough space in local arrays
c     if not, truncate number of hits to track...
      if(hit_h.nok.gt.tpt_mxhit) then
        write(6,*) ' tpt local araays not big enough',hit_h.nok,tpt_mxhit
        hit_h.nok=tpt_mxhit
      endif

C     Sort the TPC hits according to row/sector field
      call timed(time_now)
      time_all = time_all + time_now
      do i=1,hit_h.nok
         xglobal(1)=hit(i).x
         xglobal(2)=hit(i).y
         xglobal(3)=10.0
         iret=tgc_global_to_local(isect,xglobal,xlocal)
         if(isect.gt.12) isect=24-isect
         if(isect.eq.0) isect=12
         hit(i).row=isect*100+mod(hit(i).row,100)
      end do
c

***************************************  and so on .......