Creating an external file with data

GenD · January 30, 2019, 18:00

Hi,
I'm trying to create an external file with data after each time step. To do this I use DEFINE_EXECUTE_AT_END macro, but I've some problems.

First of all, in the generated file, the only thing that is saving is the data for the last time step, but I want to have it for every one, so I suppose it just overwrites every time step. I thought I will omit this issue by using arrays, but I just can't get through with them. Could you please help me solve it?

Secondly, there happen to be another problem with macros for temperature (C_T(c,t)) and other, cause ANSYS says that there are no initialized variables of c and t, but in my code I have them.

I will put code in here.

Maybe whole idea is wrong? Could you please assist me with this?

Code:

#include "udf.h"

int i = 0;

real rho[10000];
real T[10000];
real velocity[10000];
real r_num[10000];
real time[10000];

DEFINE_EXECUTE_AT_END(write_file)
{
		
		Thread *t;
		cell_t c;
		T[i] = C_T(c, t);
		rho[i] = C_R(c, t);
		real mu = 0.001003;
		velocity[i] = C_V(c, t);
		real diameter = 0.038;
		r_num[i] = ((rho[i] * pow(diameter, 2) * velocity[i]) / mu);
		time[i] = CURRENT_TIME;

		FILE *fptr;

		fptr = fopen("example.txt", "w");

		fprintf(fptr, "Temperature       Density       Viscosity       Reynolds number       Time\n");
		fprintf(fptr, "%4.2f %4.2f %4.6f %4.2f %4.3f\n", T[i], rho[i], mu, r_num[i], time[i]);

		fclose(fptr);

		i++;
}

gearboy · January 30, 2019, 21:30

Quote:

Originally Posted by GenD

Hi,
I'm trying to create an external file with data after each time step. To do this I use DEFINE_EXECUTE_AT_END macro, but I've some problems.

First of all, in the generated file, the only thing that is saving is the data for the last time step, but I want to have it for every one, so I suppose it just overwrites every time step. I thought I will omit this issue by using arrays, but I just can't get through with them. Could you please help me solve it?

Secondly, there happen to be another problem with macros for temperature (C_T(c,t)) and other, cause ANSYS says that there are no initialized variables of c and t, but in my code I have them.

I will put code in here.

Maybe whole idea is wrong? Could you please assist me with this?

Code:

#include "udf.h"

int i = 0;

real rho[10000];
real T[10000];
real velocity[10000];
real r_num[10000];
real time[10000];

DEFINE_EXECUTE_AT_END(write_file)
{
        
        Thread *t;
        cell_t c;
        T[i] = C_T(c, t);
        rho[i] = C_R(c, t);
        real mu = 0.001003;
        velocity[i] = C_V(c, t);
        real diameter = 0.038;
        r_num[i] = ((rho[i] * pow(diameter, 2) * velocity[i]) / mu);
        time[i] = CURRENT_TIME;

        FILE *fptr;

        fptr = fopen("example.txt", "w");

        fprintf(fptr, "Temperature       Density       Viscosity       Reynolds number       Time\n");
        fprintf(fptr, "%4.2f %4.2f %4.6f %4.2f %4.3f\n", T[i], rho[i], mu, r_num[i], time[i]);

        fclose(fptr);

        i++;
}

You can use "append" flag instead of "overwrite" flag when opening a file.
fptr = fopen("example.txt", "a+");

GenD · January 31, 2019, 20:05

Thank you gearboy. It really helped me.

Now, I struggle with the second problem. The code looks now like this.

Code:

#include "udf.h"

int i = 0;

real rho[10000];
real T[10000];
real velocity[10000];
real r_num[10000];
real time[10000];

cell_t c;
Thread *t;

DEFINE_ON_DEMAND(on_demand_write)
{
	FILE *fptr;

	fptr = fopen("example.txt", "w");

	fprintf(fptr, "Temperature       Density       Viscosity       Reynolds number       Time\n");

	fclose(fptr);
	
}

DEFINE_EXECUTE_AT_END(write_file_at_end)
{

		T[i] = C_T(c, t);
		rho[i] = C_R(c, t);
		real mu = 0.001003;
		velocity[i] = C_V(c, t);
		real diameter = 0.038;
		r_num[i] = ((rho[i] * pow(diameter, 2) * velocity[i]) / mu);
		time[i] = CURRENT_TIME;

		FILE *fptr;

		fptr = fopen("example.txt", "a+");

		fprintf(fptr, "%4.2f                 %4.2f        %4.6f              %4.2f            %4.3f\n", T[i], rho[i], mu, r_num[i], time[i]);

		fclose(fptr);

		i++;

It compiles fine, without any error, but then after I start simulation, I got an error:

Node 0: Process 14620: Received signal SIGSEGV.

================================================== ============================
MPI Application rank 0 exited before MPI_Finalize() with status 2
The fl process could not be started.

I think it is connected with macros C_T(c, t), C_R(c, t) and C_V(c, t), because, when I put instead of those macros just some numbers, it works fine. Do you have any idea, how to solve this?

gearboy · February 1, 2019, 05:11

Quote:

Originally Posted by GenD

Thank you gearboy. It really helped me.

Now, I struggle with the second problem. The code looks now like this.

Code:

#include "udf.h"

int i = 0;

real rho[10000];
real T[10000];
real velocity[10000];
real r_num[10000];
real time[10000];

cell_t c;
Thread *t;

DEFINE_ON_DEMAND(on_demand_write)
{
    FILE *fptr;

    fptr = fopen("example.txt", "w");

    fprintf(fptr, "Temperature       Density       Viscosity       Reynolds number       Time\n");

    fclose(fptr);
    
}

DEFINE_EXECUTE_AT_END(write_file_at_end)
{

        T[i] = C_T(c, t);
        rho[i] = C_R(c, t);
        real mu = 0.001003;
        velocity[i] = C_V(c, t);
        real diameter = 0.038;
        r_num[i] = ((rho[i] * pow(diameter, 2) * velocity[i]) / mu);
        time[i] = CURRENT_TIME;

        FILE *fptr;

        fptr = fopen("example.txt", "a+");

        fprintf(fptr, "%4.2f                 %4.2f        %4.6f              %4.2f            %4.3f\n", T[i], rho[i], mu, r_num[i], time[i]);

        fclose(fptr);

        i++;

It compiles fine, without any error, but then after I start simulation, I got an error:

Node 0: Process 14620: Received signal SIGSEGV.

================================================== ============================
MPI Application rank 0 exited before MPI_Finalize() with status 2
The fl process could not be started.

I think it is connected with macros C_T(c, t), C_R(c, t) and C_V(c, t), because, when I put instead of those macros just some numbers, it works fine. Do you have any idea, how to solve this?

For the confusing errors, you have to debug and trace the code step by step.

GenD · February 1, 2019, 07:36

Yes, that's exactly what I've done and it proved that a problem is with macros C_T(c, t), C_R(c, t) and C_V(c, t), and I don't know why. Does anyone know the reason?

GenD · February 2, 2019, 08:25

I've been working to make UDF work by the use of Customization Manual and cases written in all kinds of forums and I've developed a code. BUT it does not work for me, what is funny because the errors are with macros. I've tried to replace macros (C_T(c,t), C_R(c,t), C_V(c,t), C_VOLUME(c,t) ) with number 1 and it worked properly, so i don't get how to omit this. Actual version of the code is below, so if somebody knows the issue, I will be glad if you help me.

In addition I can say that I've tried to use final, proper codes from forums and Customization Manual connected with macros given above and those didn't work too.

Code:

#include "udf.h"

cell_t c;
Thread *t;
Domain *d;

DEFINE_EXECUTE_AT_END(write_file_at_end)
{
	real vol_tot = 0;
	real volume = 0;
	real mu = 0;
	real rho = 0;
	real T = 0;
	real velocity = 0;
	real r_num = 0;
	real time = 0;
	real Tavg = 0;
	real rhoavg = 0;
	real velavg = 0;

	d = Get_Domain(1);
	int thread_num = 6;
	t = Lookup_Thread(d, thread_num);

	thread_loop_c(t, d)
	{

		begin_c_loop(c, t)
		{
			T = C_T(c, t);
			rho = C_R(c, t);
			velocity = C_V(c, t);
			time = CURRENT_TIME;
			volume = C_VOLUME(c, t);
			vol_tot += volume;
			Tavg += T * volume;
			rhoavg += rho * volume;
			velavg += velocity * volume;

		}
		end_c_loop(c, t)

		Tavg /= vol_tot;
		rhoavg /= vol_tot;
		velavg /= vol_tot;
		mu = 0.001003;
		real diameter = 0.038;
		r_num = ((rhoavg * pow(diameter, 2) * velavg) / mu);
	}


		FILE *fptr;

		fptr = fopen("example.txt", "a+");

		fprintf(fptr, "%4.2f                 %4.2f        %4.6f              %4.2f            %4.3f\n", Tavg, rhoavg, mu, r_num, time);

		fclose(fptr);
}

DEFINE_ON_DEMAND(on_demand_write)
{
	FILE *fptr;

	fptr = fopen("example.txt", "w");

	fprintf(fptr, "Temperature       Density       Viscosity       Reynolds number       Time\n");

	fclose(fptr);

}

pakk · February 4, 2019, 11:22

You replaced macros C_T(c,t), C_R(c,t), C_V(c,t) and C_VOLUME(c,t) with number 1, and it worked.

Did you try to replace macros C_T(c,t) and C_R(c,t) with one (so leaving C_V(c,t) and C_VOLUME(c,t))?
If that gives no error, you know the problem is in C_T or C_R.
If so, try only C_T.

And make sure (double sure) that you initialize your data before you run this macro.

GenD · February 7, 2019, 16:14

Hi,
I've applied your plan of troubleshooting and as a result I got that C_T(c, t) (so temperature) is a problem. Any other like macros for density, volume, etc. work well. Do you have any idea, why is that?

Yes, of course I initialize data before calculations. It is impossible do to so without it.

January 30, 2019, 18:00	Creating an external file with data	#1
GenD New Member GenD Join Date: Nov 2017 Posts: 23 Rep Power: 9	Hi, I'm trying to create an external file with data after each time step. To do this I use DEFINE_EXECUTE_AT_END macro, but I've some problems. First of all, in the generated file, the only thing that is saving is the data for the last time step, but I want to have it for every one, so I suppose it just overwrites every time step. I thought I will omit this issue by using arrays, but I just can't get through with them. Could you please help me solve it? Secondly, there happen to be another problem with macros for temperature (C_T(c,t)) and other, cause ANSYS says that there are no initialized variables of c and t, but in my code I have them. I will put code in here. Maybe whole idea is wrong? Could you please assist me with this? Code: #include "udf.h" int i = 0; real rho[10000]; real T[10000]; real velocity[10000]; real r_num[10000]; real time[10000]; DEFINE_EXECUTE_AT_END(write_file) { Thread t; cell_t c; T[i] = C_T(c, t); rho[i] = C_R(c, t); real mu = 0.001003; velocity[i] = C_V(c, t); real diameter = 0.038; r_num[i] = ((rho[i] pow(diameter, 2) * velocity[i]) / mu); time[i] = CURRENT_TIME; FILE *fptr; fptr = fopen("example.txt", "w"); fprintf(fptr, "Temperature Density Viscosity Reynolds number Time\n"); fprintf(fptr, "%4.2f %4.2f %4.6f %4.2f %4.3f\n", T[i], rho[i], mu, r_num[i], time[i]); fclose(fptr); i++; }

January 31, 2019, 20:05		#3
GenD New Member GenD Join Date: Nov 2017 Posts: 23 Rep Power: 9	Thank you gearboy. It really helped me. Now, I struggle with the second problem. The code looks now like this. Code: #include "udf.h" int i = 0; real rho[10000]; real T[10000]; real velocity[10000]; real r_num[10000]; real time[10000]; cell_t c; Thread t; DEFINE_ON_DEMAND(on_demand_write) { FILE fptr; fptr = fopen("example.txt", "w"); fprintf(fptr, "Temperature Density Viscosity Reynolds number Time\n"); fclose(fptr); } DEFINE_EXECUTE_AT_END(write_file_at_end) { T[i] = C_T(c, t); rho[i] = C_R(c, t); real mu = 0.001003; velocity[i] = C_V(c, t); real diameter = 0.038; r_num[i] = ((rho[i] * pow(diameter, 2) * velocity[i]) / mu); time[i] = CURRENT_TIME; FILE *fptr; fptr = fopen("example.txt", "a+"); fprintf(fptr, "%4.2f %4.2f %4.6f %4.2f %4.3f\n", T[i], rho[i], mu, r_num[i], time[i]); fclose(fptr); i++; It compiles fine, without any error, but then after I start simulation, I got an error: Node 0: Process 14620: Received signal SIGSEGV. ================================================== ============================ MPI Application rank 0 exited before MPI_Finalize() with status 2 The fl process could not be started. I think it is connected with macros C_T(c, t), C_R(c, t) and C_V(c, t), because, when I put instead of those macros just some numbers, it works fine. Do you have any idea, how to solve this?

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February 1, 2019, 07:36		#5
GenD New Member GenD Join Date: Nov 2017 Posts: 23 Rep Power: 9	Yes, that's exactly what I've done and it proved that a problem is with macros C_T(c, t), C_R(c, t) and C_V(c, t), and I don't know why. Does anyone know the reason?

February 4, 2019, 11:22		#7
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	You replaced macros C_T(c,t), C_R(c,t), C_V(c,t) and C_VOLUME(c,t) with number 1, and it worked. Did you try to replace macros C_T(c,t) and C_R(c,t) with one (so leaving C_V(c,t) and C_VOLUME(c,t))? If that gives no error, you know the problem is in C_T or C_R. If so, try only C_T. And make sure (double sure) that you initialize your data before you run this macro.

February 7, 2019, 16:14		#8
GenD New Member GenD Join Date: Nov 2017 Posts: 23 Rep Power: 9	Hi, I've applied your plan of troubleshooting and as a result I got that C_T(c, t) (so temperature) is a problem. Any other like macros for density, volume, etc. work well. Do you have any idea, why is that? Yes, of course I initialize data before calculations. It is impossible do to so without it.