[BIANBOSHEN]

Dear all,
when I try to use the following udf code to define droplet diameter, the 'error: udf received a fatal signal(segmentation fault)' is appeared.
DEFINE_PROPERTY(droplet_diam, c, mix_th)
{
real bubble_diam;
real max_size,min_size;
real vg;
real Reg;
Thread *pri_th, *sec_th;
pri_th = THREAD_SUB_THREAD(mix_th,0);
sec_th = THREAD_SUB_THREAD(mix_th,1);
max_size=1e-1;
min_size=1e-6;
vg=sqrt(pow(C_U(c,pri_th),2)+pow(C_V(c,pri_th),2)+ pow(C_W(c,pri_th),2));// vapor_v
Reg=C_R(c,pri_th)*vg*0.008/C_MU_EFF(c,pri_th);// Reynolds number
bubble_diam=0.00796*0.026/C_R(c,pri_th)/pow(C_VOF(c,pri_th)*vg,2)*pow(Reg,2/3)*pow(C_R(c,pri_th)/C_R(c,sec_th),-1/3)*pow(C_MU_EFF(c,pri_th)/C_MU_EFF(c,sec_th),2/3);
if (bubble_diam > max_size)
{
bubble_diam = max_size;
}
else if (bubble_diam < min_size)
{
bubble_diam = min_size;
}

return bubble_diam;
}