[behest]

Dear all,
I've written a UDF to compute the length scale of DES; the problem is that a error is obtained when I want to compile in Fluent. the error relates line 21 (c_face_loop(c,c_thread,n)). the UDF is as below:
#include "udf.h"

DEFINE_ON_DEMAND(rls)
{
Domain *domain=Get_Domain(ROOT_DOMAIN_ID);
Thread *c_thread;
cell_t c;
face_t f;
Thread *tf;
Node *node;
int n,k,counter;
real delx,dely,delz,deltamax,maxx=0,maxy=0,maxz=0;
float x[10],y[10],z[10];

thread_loop_c(c_thread,domain) /*loops over all cell threads in domain*/
{
begin_c_loop(c,c_thread) /* loops over cells in a cell thread */
{
c_face_loop(c,c_thread,n) /* loops over faces in a cell thread */
{
f=C_FACE(c,c_thread,n);
tf = C_FACE_THREAD(c,c_thread,n);
counter=0;
f_node_loop(f,c_thread,n) /* loops over nodes in a face thread */
{
node=F_NODE(c,c_thread,n);
x[counter]=NODE_X(node);
y[counter]=NODE_Y(node);
z[counter]=NODE_Z(node);
++counter;
}
for (i=0; i<(counter-1); ++i)
{
for (k=i+1; k<counter; k++)
{
delx=fabs(x[i]-x[k]);
dely=fabs(y[i]-y[k]);
delz=fabs(z[i]-z[k]);
if (delx>maxx)
{
maxx=delx;
}
if (dely>maxy)
{
maxy=dely;
}
if (delz>maxz)
{
maxz=delz;
}
}
}
}
deltamax=0;
if (deltamax<maxx)
{
deltamax=maxx;
}
if (deltamax<maxy)
{
deltamax=maxy;
}
if (deltamax<maxz)
{
deltamax=maxz;
}
C_UDMI(c,c_thread,0)=sqrt(C_K(c,c_thread))/(0.09*0.61*deltamax*C_O(c,c_thread));
}
end_c_loop(c,c_thread)
}
}

It would be appricaiated if you make a comment about this problem.

[pakk]

This code compiles for me without any problem. Which version of Fluent are you using? (I tested it in 14.5.0, 3d, single precision)

[behest]

Hello, Thank you very much. As you said, when this code would be compiled, any errors is occured. you are right. Before that, I used interprate at first and I recieved the error, but when I apply compile, the error is not existed too.

any way, I wrote the udf and it is compile too; now, how can I pick the result up? actually, when I want to execute on demand, I recived an error as below:

Error:
C:\PROGRA~1\ANSYSI~1\v145\fluent\fluent14.5.0\win6 4\3ddp\fl1450s.exe received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: #f

Do you know how will it be solved?

Originally Posted by pakk

This code compiles for me without any problem. Which version of Fluent are you using? (I tested it in 14.5.0, 3d, single precision)

[pakk]

ACCESS_VIOLATION means that the program is trying to access something which is impossible.

It could for example mean that in the line "x[counter]=NODE_X(node);", NODE_X(node) is not defined. Or that x[counter] is not defined.
You have to find out where it went wrong. See how far the program got by writing something to the screen, for example. Debug it.

[behest]

thank you very much. The problem has been solved by your guidelines.

Originally Posted by pakk

ACCESS_VIOLATION means that the program is trying to access something which is impossible.

It could for example mean that in the line "x[counter]=NODE_X(node);", NODE_X(node) is not defined. Or that x[counter] is not defined.
You have to find out where it went wrong. See how far the program got by writing something to the screen, for example. Debug it.