udf-plz help
 

hi
In my udf, A is introduced such:
A= T*(2*C_K(cell, thread)/3-2*nu_t*S11)*C_T_G(cell,thread)[0]+T*(-2*nu_t*S12)*C_T_G(cell,thread)[1];
(I think A is a vector)
so,how can I apply gradiant of A in my program?
because C_A_G(c,t,i) didn't define in user guide.
thank you for your help