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:         enddo
        enddo
      enddo
      !$OMP END DO NOWAIT
    enddo
  
    !$OMP CRITICAL (u0Hu0)
    do istate=1,N_st
  
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
  