Hi,

I am wondering if there is a way to pass a value of a variable from one routine to another. For example, I have a DEFINE_ON_DEMAND function that calculates a value for velocity. I want to pass this velocity to my DEFINE_PROFILE function. C_UDMI is a user-defined memory location for cells. Is there one for just a single value?

Thanks,

Mark

I dont know of any way other than UDM's to pass variables between macros. I suggest you put a thread loop in your DEFINE_ON_DEMAND macro and fills all cells in the domain with with the same velocity value in a UDM. Then when you access the UDM in DEFINE_PROFILE it doesnt matter which cell is accessed because they all have same value.

Use a global variable. Luca

For clarity, I am using compiled udfs.

Luca,

I have tried this but cannot seem to get it to work. I am relatively new with C and am trying to figure out where I declare the variables as "extern". Is it in the routine I am working with it? just in the .c file? or in a .h file which I then include?

Also, when using external variables do all of the routines have to be in the same .c file?

Thanks, Mark

Alec

Thanks for the suggestion, but I would like to reduce the looping if at all possible.

Mark

I use a unique file, if you have more than 1 file you should pay attention. I declare a variable outside an EXECUTE_ON_DEMAND or DEFINE_PROFILE funtion. This way I can modifiy its value outside the function. I hope to be clear. Luca

Hi Luca,

Do you also declare that variable as "extern" inside the function?

Mark

Luca, is it possible to initialize UDM-0 with specified x and y values?

For instance, lets say we have a pipe and I know the experimental values of velocities at certain points in the radial direction. However, I do not wish to use these values in my CFD simulation. Instead, I wish to use these values later in one of my custom field functions that calculates say the sum of squared errors between the simulated and experimental velocities.

So how can I store user-specified values in a UDM for later postprocessing?

I think u can use the UDM defined in 'on-demand' UDF to 'profile' udf. For post-processing, u can define another UDM with expt. values or define custom field function.

[arkie87]

Originally Posted by Mark
;120936

For clarity, I am using compiled udfs.

Luca,

I have tried this but cannot seem to get it to work. I am relatively new with C and am trying to figure out where I declare the variables as "extern". Is it in the routine I am working with it? just in the .c file? or in a .h file which I then include?

Also, when using external variables do all of the routines have to be in the same .c file?

Thanks, Mark

Global variables are defined outside of specific fluent macros i.e. where you put "#include udf.h"

something like this:

// Include Necessary Libraries //
#include "udf.h"
// Global Variables
int counter;

// Initialization Function
DEFINE_INIT(initialization,d)
{
}