Udf segmentation violation
 

Hello people,

I'm trying to write down a simple UDF which will calculate the pressure time derivative for each cell and time step and will also assign a zero value to the z velocity. The pressure time derivative and z-velocity value will also be saved as two new variables.
I managed to compile and hook the function. However, when running the calculation I always get a SEGMENTATION VIOLATION and the simulation is terminated.

The UDF I have coded is the following:

/********************/
#include "udf.h"
#include "mem.h"

DEFINE_ADJUST(dp_dt_uzero,d)
{
Thread *t;
cell_t c;
real p1, p2, dt=0.05;

thread_loop_c(t,d)
{
begin_c_loop(c,t)
{
/* Read pressure from previous and second previous time steps */
p1 = C_P_M1(c,t);
p2 = C_P_M2(c,t);
C_UDMI(c,t,0) = (p1 - p2) / (dt);

/* Assign value zero to uz */
C_UDMI(c,t,1) = 0.;
}
end_c_loop(c,t)
}
}
/********************/

Should I have looping in cells and threads?
I tried without the loops and still have the same problem.

Additionally, I am running in parallel. Might the code need to be parallelized?

Thanks! :)