subroutine hec_ntuple
c
c produce system histograms
c
      implicit none
c
      include'hec_par.inc'      !shared parameters
      include'hec_datacard.inc' ! datacard values
c
c if ntuple package is turned off -> return
c
      if (mk_ntp .le. 0) return
c
c book system ntuples
c
      call hec_ntuple_ini
c
c book user ntuples if requested
c
      if (nt_user_switch .ge. 1) call user_ntuple_block_ini      
c
c do one pass over data to fill the ntuples
c
      call hec_ntuple_pass1
c
c output and delete system ntuples
c
      call hec_ntuple_ter
c
      print *, ' *** end of system ntuple production'
c
      end