[fatemeh chitgarha]

I want to calculate an integral spatial. One of the following variables in integral is a UDS function of time and place(UDSI(X,t)).I want to calculate this Integral in every time step in a preprocessing stage. But i confused!
Do FLUENT UDS information saves at everyTIME step? What should I do??? HOW call info?????????
Here, I attached my UDF file.
Maybe you can find the problem and help me!
Thank you very much!

#include "udf.h"
DEFINE_ON_DEMAND(on_demand)
{
Domain *d;
Thread *t;
cell_t c;
real sum_diss=0.;
real sum_dissa=0.;
d = Get_Domain(1);
thread_loop_c(t,d)
{
begin_c_loop(c,t)
{
for(CURRENT_TIME =15.491; CURRENT_TIME > 0.001; CURRENT_TIME--)
sum_diss += C_UDSI(c,t,0) * C_R(c,t) * C_VOLUME(c,t);
sum_dissa += C_UDSI(c,t,0) * C_VOLUME(c,t);
end_c_loop(c,t)
}
begin_c_loop(c,t)
{
C_UDMI(c, t, 1) = sum_diss/sum_dissa;
}
end_c_loop(c,t)
}
}