define a second order
 

I want to implement the diffusion of a scalar \bigtriangledown\cdot(\Gamma\bigtriangledown\phi) in the source term , my ideal is use another scalar in DEFINE_ADUST, then get the gradient of the scalar by C_UDSI_G in the DEFINE_SOURCE finally use NV_DOT(C_UDSI_G,A);
can that be possible? has anybody done it before ?
any suggestion is appreciate !
thaks

I have post a new one ,but I donnot know how to delete this one:(