c*******************************************************
c  out_juxta_distance(n,ntime)
c
c np600=0 output: 1. if a pair has the distance below the criterique
c                    record them into npairs and outputting the the 
c                    trajectories until the distance is larger than 3
c                    critical length
c                 2. nflag(ijudge)=0 no pair into this distance
c                    ..           =1 right inside
c                    ..           =2 out of the range
c              if all the criteria are checked once, (all flags are 2)
c                stop the trajectory.

      subroutine out_juxta_distance(n,ntime)
      implicit double precision(a-h, o-z)
      parameter(maxpair=100,maxa=500,maxjudge=10)
      common /juxtapair/ npair,npairs(maxpair,2),nflag(maxpair,maxjudge)
     +,njudge, sjuxta_judge(maxjudge),mp(maxpair)
      common/matrix/x(maxa,3),bangle(maxa)

c 1. check if some flags are still 0, and if all 2, stop
      mtmp=0
      kflag=0
      mmax=2*njudge
      do i=1,njudge
         if (nflag(1,i).eq.0) then
            kflag=1
         endif
            mtmp=mtmp+nflag(1,i)
      enddo

      if (mtmp.eq.mmax) then
         stop
      endif

c 2. when flag=0 searching for good pair candidates
      rrmin=100 
      minpair1=0
      minpair2=0
      if (kflag.eq.1) then
        inter=5
        do i=1,n-inter
        jmax=min(n,n-inter+i)
            do j=i+inter,jmax
              rr=0
              do k=1,3
                 rr=rr+(x(i,k)-x(j,k))*(x(i,k)-x(j,k))
              enddo
              if (rr.lt.rrmin) then
                 rrmin=rr
                 minpair1=i
                 minpair2=j
              endif
            enddo
          enddo
          rrmin=dsqrt(rrmin)
c          write(*,*) ntime, minpair1,minpair2,rrmin
          do i=1,njudge
             if ((nflag(1,i).eq.0).and.(rrmin.le.sjuxta_judge(i))) then
             nflag(1,i)=1
             npairs(i,1)=minpair1
             npairs(i,2)=minpair2
             mp(i)=600+i
             write(888,*) minpair1,minpair2,mp(i),sjuxta_judge(i)
                    call flush(888)
             sjuxta_judge(i)=sjuxta_judge(i)*3.0
c start a monitor
         
           
c the inside and outside criteria are different by the factor of 3
             endif
          enddo
       endif

c 3. check the pairs inside nflag(1,i)=1
c      if distance is inside the range, output into mp(i)
c      otherwise stop the output and set nflag(1,i)=2
       do i=1,njudge
          if (nflag(1,i).eq.1) then
             rr=0
             do j=1,3
             rr=rr+(x(npairs(i,1),j)-x(npairs(i,2),j))*(x(npairs(i,1),j)
     + -x(npairs(i,2),j))    
             enddo
             rr=dsqrt(rr)
             if (rr.lt.sjuxta_judge(i)) then
                write(mp(i),700)  npairs(i,1),npairs(i,2),ntime,rr
                call flush(mp(i))
             else
                nflag(1,i)=2
             endif
          endif
       enddo
             

700   format(i5,1x,i5,1x,i8,1x,g11.5)

      return
      end