anchor.diff:    
     comb_step = 1d0 / dfloat(comb_teeth) * (1d0 - cweight(first_det_of_comb-1))
     
  -  stato = 1d0 - comb_step + 1d-5
  +  stato = 1d0 - comb_step! + 1d-5
     do i=comb_teeth, 1, -1
       first_det_of_teeth(i) = pt2_find(stato, cweight)
       stato -= comb_step
     end do
     first_det_of_teeth(comb_teeth+1) = N_det_generators + 1
  +  first_det_of_teeth(1) = first_det_of_comb
     if(first_det_of_teeth(1) /= first_det_of_comb) stop "comb provider"
     
   END_PROVIDER
  
positive.code:   end do
    
    do i=comb_teeth, 1, -1
      if(first_det_of_teeth(i) <= first_teeth) then
        first_teeth = i
        exit
      end if
  
negative.code:   
    comb_step = 1d0/dfloat(comb_teeth)
    do i=1,N_det_generators
      if(weight(i)/norm_left < comb_step/2d0) then
        first_det_of_comb = i
        exit
      end if
  