| Hosea_Chan |
November 22, 2020 21:17 |
C_UDMI function causing SIGSEGV error
Dear forum users,
I am working on a DEFINE_ADJUST function to compute the average velocity at the inlet of the cell zone and store the average velocity in the cells with C_UDMI function, which will be used to compute the momentum source term later. The code is as follows:
Code:
DEFINE_ADJUST(update,d)
{
int id_a[cell_zones] = {17,21}; /* get zone id of channel-in later, need input */
int id_v[cell_zones] = {6,7}; /* get zone id of channel volume later, need input */
int i;
for (i=0;i<2;i++) {
#if !RP_HOST
real A[ND_ND];
real tfa = 0.0;
real tfi = 0.0;
real Ux = 0.0;
face_t f;
cell_t c;
Thread* t1=Lookup_Thread(d,id_a[i]);
Thread* t2 = Lookup_Thread(d,id_v[i]);
begin_f_loop(f, t1)
{
if PRINCIPAL_FACE_P(f,t1)
{
F_AREA(A,f,t1);
tfa += NV_MAG(A);
/* summing the x-velocity of face */
tfi += F_U(f,t1)*NV_MAG(A);
}
}
end_f_loop(f, t1)
tfi=PRF_GRSUM1(tfi);
tfa=PRF_GRSUM1(tfa);
Ux = tfi / tfa;
Message0("Average zone %d U:%12.4e\n",i, Ux);
Message0("Begin store c loop %d.\n",i);
begin_c_loop(c,t2)
{
if (FLUID_THREAD_P(t2) && NNULLP(THREAD_STORAGE(t2, SV_UDM_I)))
{
C_UDMI(c,t2,1) = Ux;
}
}
end_c_loop(c,t2)
Message0("End store c loop %d.\n",i);
#endif
}
}
However, I get a SIGSEGV error when I run the code. After isolating the code part by part, it seems that the line "C_UDMI(c,t2,1) = Ux;" is causing the problem as the code runs fine if I commented the line. I have reserved UDM slots in the Fluent GUI. I also used C_UDMI(c,t2,0) for storing the total volume in the DEFINE_INIT code earlier:
Code:
DEFINE_INIT(initialize,d)
{
#if !RP_HOST
real total_volume[cell_zones];
//Domain* d;
int i;
d = Get_Domain(1);
for (i=0; i<2 ; i++)
{
cell_t c;
Thread* t2 = Lookup_Thread(d,id_v[i]);
begin_c_loop(c, t2)
Message0("Begin volume c loop %d\n",i);
{
total_volume[i] += C_VOLUME(c,t2);
}
end_c_loop(c, t2)
#if RP_NODE
total_volume[i] = PRF_GRSUM1(total_volume[i]);
#endif
Message0("Begin store c loop %d\n",i);
begin_c_loop(c,t2)
{
if (FLUID_THREAD_P(t2) && NNULLP(THREAD_STORAGE(t2, SV_UDM_I)))
{
C_UDMI(c,t2,0) = total_volume[i];
}
}
end_c_loop(c,t2)
Message0("total_volume of zone %d: %12.4e\n", i,total_volume[i]);
}
#endif /* !RP_HOST */
}
It used to cause SIGSEGV as well, but with reference to another post with similar issue, the line "if (FLUID_THREAD_P(t2) && NNULLP(THREAD_STORAGE(t2, SV_UDM_I)))" seem to have solved the problem in the DEFINE_INIT code but not the DEFINE_ADJUST code. A link to the refered post is here: https://www.cfd-online.com/Forums/fl...emory-udf.html
Thank you for your help in advance!
Best regards,
Hosea |
