anchor.diff:        ix=ixt;iy=iyt;iz=izt
         ixt=-iy+NLx/4;iyt=ix+NLy/4;izt=iz+NLz/4 ! T_3
         ixt=mod(ixt+2*NLx,NLx);iyt=mod(iyt+2*NLy,NLy);izt=mod(izt+2*NLz,NLz)
  -      itable_sym(2,i)=Lxyz(ixt,iyt,izt)
  +      itable_sym(2,Lxyz(ixt,iyt,izt))=i
       end do
   !===  end  diamond(4) ====================================================================
     else if((Sym == 8).and.(crystal_structure == 'tetragonal')) then
  
positive.code:   end do
  
  ! make symmetry table
    if(Sym == 1)then
    else if((Sym == 8).and.(crystal_structure == 'diamond2')) then
  !=== start diamond(8) ====================================================================
  
negative.code:       ix=ixt;iy=iyt;iz=izt
        ixt=-iy;iyt=ix;izt=iz ! T_3
        ixt=mod(ixt+2*NLx,NLx);iyt=mod(iyt+2*NLy,NLy);izt=mod(izt+2*NLz,NLz)
        itable_sym(4,Lxyz(ixt,iyt,izt))=i
      end do
  !===  end  diamond(8) ====================================================================
    else
  