anchor.diff:    do sh=1,shortcut(0,2)
       do i=shortcut(sh,2),shortcut(sh+1,2)-1
         org_i = sort_idx(i,2)
  -      do j=shortcut(sh,2),i-1
  +      do j=shortcut(sh,2),shortcut(sh+1,2)-1
           org_j = sort_idx(j,2)
           ext = popcnt(xor(sorted(1,i,2), sorted(1,j,2)))
           do ni=2,Nint
  
positive.code:       
        do i=shortcut(sh,1),shortcut(sh+1,1)-1
          org_i = sort_idx(i,1)
          if(sh==sh2) then
            endi = i-1
          else
            endi = shortcut(sh2+1,1)-1
          end if
          do ni=1,Nint
            sorted_i(ni) = sorted(ni,i,1)
          enddo
          
   jloop: do j=shortcut(sh2,1),endi
            org_j = sort_idx(j,1)
            ext = exa + popcnt(xor(sorted_i(1), sorted(1,j,1)))
            if(ext > 4) then
  
negative.code:           call i_H_j(keys_tmp(1,1,org_j),keys_tmp(1,1,org_i),Nint,hij)
            do istate=1,N_st
              vt (istate,org_i) = vt (istate,org_i) + hij*ut(istate,org_j)
            enddo
          enddo jloop
        enddo
  