[grubi]

Hi everyone

I am trying to create an UDF in which I want to determine the second derivative of an UDS that I applied. The first derivative gave no problems!

And then I assign the derivative of the first UDS to a new UDS and I do the gradient again on this new UDS, and the second derivative is zero...

Can someone help me?



#include "udf.h"



DEFINE_ON_DEMAND(store_gradient)

{

Domain *domain;

cell_t c;

Thread *t;

domain=Get_Domain(1);



thread_loop_c (t,domain)

{

begin_c_loop (c,t)

{

C_UDMI(c,t,0) = 0-C_UDSI_G(c,t,0)[0];

C_UDMI(c,t,1) = 0-C_UDSI_G(c,t,0)[1];

C_UDMI(c,t,2) = NV_MAG(C_UDSI_G(c,t,0)); /*UNTIL HERE IS RIGHT*/



C_UDSI(c,t,1)=0-C_UDSI_G(c,t,0)[0];

C_UDSI(c,t,2)=0-C_UDSI_G(c,t,0)[1];

C_UDMI(c,t,3)=C_UDSI_G(c,t,1)[0]+C_UDSI_G(c,t,2)[1]; /*this line gives me 0*/

}

end_c_loop (c,t)

}

}