*     maximum numb. of doublets and troplets 
*     to fill DEBUG nt-uple
      parameter (ndblt_max_nt=0.2*ndblt_max) !maximum number of doublets
      parameter (ntrpt_max_nt=0.2*ntrpt_max) !maximum number of triplets
      logical good2_nt
      integer nev2_nt
      integer ndblt_nt,ntrpt_nt
      real
     $     alfayz1_nt(ndblt_max_nt),  !Y0
     $     alfayz2_nt(ndblt_max_nt)   !tg theta-yz
      real
     $     alfaxz1_nt(ntrpt_max_nt),  !X0
     $     alfaxz2_nt(ntrpt_max_nt),  !tg theta-xz
     $     alfaxz3_nt(ntrpt_max_nt)   !1/r
      common/event_nt/good2_nt,nev2_nt      !commons for DEBUG nt-uple!
      common/hough_yz/                      !   /   /   /   /   /   / !
     $     ndblt_nt                         !  /   /   /   /   /   /  !
     $     ,alfayz1_nt,alfayz2_nt           ! /   /   /   /   /   /   !
     $     ,db_cloud_nt                     !/   /   /   /   /   /   /!
      common/hough_xz/                      !   /   /   /   /   /   / !
     $     ntrpt_nt,                        !  /   /   /   /   /   /  !
     $     alfaxz1_nt,alfaxz2_nt,alfaxz3_nt ! /   /   /   /   /   /   !
     $     ,tr_cloud_nt                     !/   /   /   /   /   /   /!
*     -----------------------------------------------------------
*     Number of YZ and XZ clouds
      integer nclouds_yz_nt,nclouds_xz_nt
*     -----------------------------------------------------------
*     doublet and triplet ID in the selected clouds
      integer db_cloud_nt(ndblt_max_nt)
      integer tr_cloud_nt(ntrpt_max_nt)
*     -----------------------------------------------------------
*     number of points in the cloud
      integer ptcloud_yz_nt(ncloyz_max)
      integer ptcloud_xz_nt(ncloxz_max)
*     -----------------------------------------------------------
*     average parameters
      real alfayz1_av_nt(ncloyz_max),alfayz2_av_nt(ncloyz_max)
      real alfaxz1_av_nt(ncloxz_max),alfaxz2_av_nt(ncloxz_max)
     $     ,alfaxz3_av_nt(ncloxz_max)
*     -----------------------------------------------------------
      common/clouds_yz_nt/                       !commons for DEBUG nt-uple!
     $     nclouds_yz_nt                         !   /   /   /   /   /   / !
     $     ,alfayz1_av_nt,alfayz2_av_nt          !  /   /   /   /   /   /  !
     $     ,ptcloud_yz_nt                        ! /   /   /   /   /   /   !
      common/clouds_xz_nt/                       !/   /   /   /   /   /   /!
     $      nclouds_xz_nt                        !   /   /   /   /   /   / !
     $     ,alfaxz1_av_nt,alfaxz2_av_nt,alfaxz3_av_nt ! /   /   /   /   /  !
     $     ,ptcloud_xz_nt                        ! /   /   /   /   /   /   !