anchor.diff:        X2CIJ(5,6) = (1._rs/(2._rs*sqrt(2._rs)))*X(19)
         X2CIJ(4,6) = (1._rs/(2._rs*sqrt(2._rs)))*X(20)
         X2CIJ(4,5) = (1._rs/(2._rs*sqrt(2._rs)))*X(21)
  -      
  +
         do i=1,6
            do j=i,6
               X2CIJ(j,i) = X2CIJ(i,j)
            enddo
         enddo
  -      
  +
      end function X2CIJ
   !-------------------------------------------------------------------------------
   
  
positive.code:          C(5,5) = C(4,4) ; C(6,6) = C(4,4)
           C(1,2) = (C(3,3)-2.d0*C(4,4))
           C(1,3) = C(1,2) ; C(2,3) = C(1,2) ;
        endif   
        
  !   ** Make symmetrical
        do i=1,6
           do j=i,6
  
negative.code:       real(rs),intent(in) :: C(6,6)
        real(rs)            :: CIJ_rot90y(6,6),R(6,6)
        integer             :: i,j
  
     R(1,1)=C(3,3); R(1,2)=C(2,3) ; R(1,3)=C(1,3) ; R(1,4)=C(3,6) ; R(1,5)=-C(3,5); R(1,6)=-C(3,4)
     R(2,2)=C(2,2); R(2,3)=C(1,2) ; R(2,4)=C(2,6) ; R(2,5)=-C(2,5); R(2,6)=-C(2,4)
     R(3,3)=C(1,1); R(3,4)=C(1,6) ; R(3,5)=-C(1,5); R(3,6)=-C(1,4)
     R(4,4)=C(6,6); R(4,5)=-C(5,6); R(4,6)=-C(4,6)
     R(5,5)=C(5,5); R(5,6)=C(4,5)
     R(6,6)=C(4,4)
  
        do i=1,6; do j=1,6; R(j,i) = R(i,j); enddo; enddo
        CIJ_rot90y = R
  
     end function CIJ_rot90y
  !-------------------------------------------------------------------------------
  
  