anchor.diff:    use posvel
     use neighbors
     use forces
  +  use timers
     implicit none
     character(30) :: init_file, proc_string
     integer :: i, unit
  
positive.code:   ! Print out initial particle positions
    frame = 0
    call particle_write
  
    return
  end subroutine init
  
negative.code:                 cbinz = binz + stz
                  do j = 1, part_count(cbinx,cbiny, cbinz)
                    nb = binpart(j,cbinx,cbiny,cbinz)
                    if(nb .le. p) cycle
                    distx = px(p) - px(nb)
                    disty = py(p) - py(nb)
                    distz = pz(p) - pz(nb)
  