[dhdh89]

I use udf for membrane calculations.

I want to use face loops to store values ​​in udm consecutively.

When the code in serial mode is calculated in parallel mode, an error occurs.

If you check the values ​​stored in udm, a value of 0 is found.

I converted the example of the customer portal to code it.
How can you convert this code to parallel use?

--------------------------------------

#include "udf.h"

#define WALLSIDE1 4
#define WALLSIDE2 9

#define UDM_NEIGHBOUR_C 0
#define UDM_NEIGHBOUR_TC 1
#define UDM_MASS_SOURCE 2

#define TOLERANCE 1E-10

#define SPECIES_NUMBER 0

#define PERMISSIVITY 1.0e-2

#define MY_PRINT Message


DEFINE_INIT(init_function,d)
{

Thread *tc1, *tc2;
Thread *tf1, *tf2;
cell_t c1, c2;
face_t f1, f2;
real f_c1[3], f_c2[3];


thread_loop_c(tc1,d)
{
begin_c_loop(c1,tc1)
{
C_UDMI(c1,tc1,UDM_NEIGHBOUR_C) = 0.0;
C_UDMI(c1,tc1,UDM_NEIGHBOUR_TC) = 0.0;
C_UDMI(c1,tc1,UDM_MASS_SOURCE) = 0.0;
}
end_c_loop(c1,tc1)
}


tf1 = Lookup_Thread(d,WALLSIDE1);
tf2 = Lookup_Thread(d,WALLSIDE2);

begin_f_loop(f1,tf1)
{
F_CENTROID(f_c1,f1,tf1);

c1 = F_C0(f1,tf1);
tc1 = THREAD_T0(tf1);

begin_f_loop(f2,tf2)
{

F_CENTROID(f_c2,f2,tf2);
if (fabs(f_c1[0]-f_c2[0]) <= TOLERANCE &&
fabs(f_c1[1]-f_c2[1]) <= TOLERANCE &&
fabs(f_c1[2]-f_c2[2]) <= TOLERANCE )
{
c2 = F_C0(f2,tf2);
tc2 = THREAD_T0(tf2);

C_UDMI(c1,tc1,UDM_NEIGHBOUR_C) = c2 + 0.1;
C_UDMI(c2,tc2,UDM_NEIGHBOUR_C) = c1 + 0.1;
C_UDMI(c1,tc1,UDM_NEIGHBOUR_TC) = THREAD_ID(tc2) + 0.1;
C_UDMI(c2,tc2,UDM_NEIGHBOUR_TC) = THREAD_ID(tc1) + 0.1;
}
}
end_f_loop(f2,tf2)
}
end_f_loop(f1,tf1)
MY_PRINT("\n Membrane initialisation completed.\n");
}

/////////////////////////////////////////

DEFINE_ADJUST(adjust_sources, d)
{
Thread *tc1, *tc2;
Thread *tf1;
cell_t c1, c2;
face_t f1;
real mass_flux, face_area, face_area_vector[3];
real massfrac1, cell_volume1;
real massfrac2, cell_volume2;

tf1 = Lookup_Thread(d,WALLSIDE1);

begin_f_loop(f1,tf1)
{

F_AREA(face_area_vector,f1,tf1);
face_area = NV_MAG(face_area_vector);

c1 = F_C0(f1,tf1);
tc1 = THREAD_T0(tf1);
cell_volume1 = C_VOLUME(c1,tc1);


c2 = (int)C_UDMI(c1,tc1,UDM_NEIGHBOUR_C);
tc2 = Lookup_Thread(d, (int)C_UDMI(c1,tc1,UDM_NEIGHBOUR_TC));
cell_volume2 = C_VOLUME(c2,tc2);

massfrac1 = C_YI(c1,tc1,SPECIES_NUMBER);
massfrac2 = C_YI(c2,tc2,SPECIES_NUMBER);

mass_flux = face_area * PERMISSIVITY * (massfrac1 - massfrac2);

C_UDMI(c1,tc1,UDM_MASS_SOURCE) = -mass_flux / cell_volume1;
C_UDMI(c2,tc2,UDM_MASS_SOURCE) = +mass_flux / cell_volume2;
}
end_f_loop(f1,tf1)

}

Thanks in advance

[AlexanderZ]

ansys fluent customization manual
chapter Parallel Considerations

best regards

[dhdh89]

Originally Posted by AlexanderZ

ansys fluent customization manual
chapter Parallel Considerations

best regards

I have already tried it.

CODE is calculated, but 0 value is stored in the process of being stored in UDM.

even
C_UDMI (c1, tc1, UDM_MASS_H2_SOURCE) = 2;
0 is also found.

[dhdh89]

Originally Posted by AlexanderZ

ansys fluent customization manual
chapter Parallel Considerations

best regards

#if !RP_HOST
#endif

I tried this code, but it is useless. Picture 1 shows the picture that succeeded in the serial mode, Picture 2 shows the error that failed in the parallel mode.

a1.jpg

a2.jpg

best regards

[AlexanderZ]

in your code you use c_loop once in DEFINE_INIT macro

thread_loop_c(tc1,d)
{
begin_c_loop(c1,tc1)
{
C_UDMI(c1,tc1,UDM_NEIGHBOUR_C) = 0.0;
C_UDMI(c1,tc1,UDM_NEIGHBOUR_TC) = 0.0;
C_UDMI(c1,tc1,UDM_MASS_SOURCE) = 0.0;
}
end_c_loop(c1,tc1)
}

0 everywhere, thats why you have 0 values.

C_UDMI (c1, tc1, UDM_MASS_H2_SOURCE) = 2;

what is it? UDM_MASS_H2_SOURCE is not defined

put the whole code you are using (testing)

go deep in ansys fluent customiztion manual,
because you are interested in faces take a look into

begin_f_loop_int
begin_f_loop_ext

besides this (faces issue) i dont see, why your code should be modified to run in parallel, it should work in both regimes

best regards

[dhdh89]

Originally Posted by AlexanderZ

in your code you use c_loop once in DEFINE_INIT macro

thread_loop_c(tc1,d)
{
begin_c_loop(c1,tc1)
{
C_UDMI(c1,tc1,UDM_NEIGHBOUR_C) = 0.0;
C_UDMI(c1,tc1,UDM_NEIGHBOUR_TC) = 0.0;
C_UDMI(c1,tc1,UDM_MASS_SOURCE) = 0.0;
}
end_c_loop(c1,tc1)
}

0 everywhere, thats why you have 0 values.

C_UDMI (c1, tc1, UDM_MASS_H2_SOURCE) = 2;

what is it? UDM_MASS_H2_SOURCE is not defined

put the whole code you are using (testing)

go deep in ansys fluent customiztion manual,
because you are interested in faces take a look into

begin_f_loop_int
begin_f_loop_ext

besides this (faces issue) i dont see, why your code should be modified to run in parallel, it should work in both regimes

best regards

Hello AlexanderZ.

I completed my code by converting the reference (UDF69) found in the customer portal. test_question is my entire code (test).

(After initialization) This code can be computed in serial mode, but in parallel mode, it cannot be computed with the following error.

PHP Code:

==============================================================================

Node 999999: Process 9616: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 0: Process 10276: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 1: Process 17332: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 2: Process 16140: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 3: Process 16116: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 4: Process 15552: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 5: Process 2596: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 6: Process 14084: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 7: Process 17948: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 8: Process 12884: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 11: Process 6856: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 14: Process 7012: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 15: Process 8276: Received signal SIGSEGV.

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


I do not know why. I tried the RP_node code and the principal face_p code, but it is useless.

This problem has been blocked for three months. I ask for help.

[AlexanderZ]

did you define enough UDMIs in fluent GUI?

problem my comes from second loop in INIT macro

  thread_loop_c(tc2,d)
  {
	  begin_c_loop(c2,tc2)
	  {

c2,tc2 are not defined, actually in your code there is no different between c1,tc1 and c2,tc2

best regards

[dhdh89]

Originally Posted by AlexanderZ

did you define enough UDMIs in fluent GUI?

problem my comes from second loop in INIT macro

  thread_loop_c(tc2,d)
  {
	  begin_c_loop(c2,tc2)
	  {

c2,tc2 are not defined, actually in your code there is no different between c1,tc1 and c2,tc2

best regards

Yes. I defined 23 UDM in GUI.

c2 and tc2 are defined.

PHP Code:

DEFINE_INIT(init_function,d)
{
  Thread *tc1, *tc2;
  Thread *tf1, *tf2;
  cell_t c1, c2;
  face_t f1, f2;
  real   f_c1[3], f_c2[3]; 


And tc1 and tc2 are obtained by the following values.

PHP Code:

 tf1 = Lookup_Thread(d,WALLSIDE1);                            
 tf2 = Lookup_Thread(d,WALLSIDE2); 


This code is from UDF69.

"mpt_accept error accept failed no such file or directory"
As soon as I pressed run calculation after initialization, I got the above error.
This is some parallel / mpi error. I can not resolve this problem yet ..

best regards

[rajeev2111]

Originally Posted by dhdh89

Yes. I defined 23 UDM in GUI.

c2 and tc2 are defined.

PHP Code:

DEFINE_INIT(init_function,d)
{
  Thread *tc1, *tc2;
  Thread *tf1, *tf2;
  cell_t c1, c2;
  face_t f1, f2;
  real   f_c1[3], f_c2[3]; 


And tc1 and tc2 are obtained by the following values.

PHP Code:

 tf1 = Lookup_Thread(d,WALLSIDE1);                            
 tf2 = Lookup_Thread(d,WALLSIDE2); 


This code is from UDF69.

"mpt_accept error accept failed no such file or directory"
As soon as I pressed run calculation after initialization, I got the above error.
This is some parallel / mpi error. I can not resolve this problem yet ..

best regards

I am also working with the same example of UDF69.c . Can you please help me with this. I am also getting the same error. How have you resolved this problem?

Thanks in advance.

[vinerm]

One reason could be UDM initialization. UDF69.c does it during initialization, however, if user forgot to hook DEFINE_INIT function, then it will lead to error. But usually, this would lead to segmentation violation. So, the other reason is parallelization. The code is quite old and not parallelized. Current version of Fluent runs in parallel even if you select serial (until you start with -t0), so, you need to parallelize it. Non-parallelized codes do not always cause syntactical problems, but logical ones, i.e., those run but give wrong results. However, sometimes, it may cause errors as well.

[AlexanderZ]

first of all show the code you are using
code above has some problems with parallelization, at least:

C_UDMI(c1,tc1,UDM_MASS_SOURCE) = -mass_flux / cell_volume1;
      C_UDMI(c2,tc2,UDM_MASS_SOURCE) = +mass_flux / cell_volume2;

put messages inside code to define the line, which leads to error

simplify code for debugging, later add necessary functionality

[rajeev2111]

I am hooking the DEFINE_INIT and DEFINE_ADJUST function in the fluent, but still the error is there. I am new to UDF writing, Can you please help me with how to parallelize a UDF or any of the UDF parallelization examples you can provide. That will be a great help for me.

code:
#include "udf.h"

#define WALLSIDE1 30
#define WALLSIDE2 5

#define UDM_NEIGHBOUR_C 0
#define UDM_NEIGHBOUR_TC 1
#define UDM_MASS_SOURCE 2

#define TOLERANCE 1E-10

#define SPECIES_NUMBER 0

#define PERMISSIVITY 1.0e-2

#define MY_PRINT Message

/* User-Defined Functions for a membrane
* permeable to one species but not to fluid
* in general. The membrane is represented
* by a wall (with facezone numbers WALLSIDE1
* and WALLSIDE2 for the wall and its shadow),
* and the mass transfer is brought about by
* source terms in the neighbouring cells.
*
* Written by James Tibbetts and Ed Wynn,
* Fluent Europe, January 2006. */

DEFINE_INIT(init_function,d)
{

Thread *tc1, *tc2;
Thread *tf1, *tf2;
cell_t c1, c2;
face_t f1, f2;
real f_c1[3], f_c2[3];

/*
This routine is run on initialisation. It sets the User-Defined
Memory to appropriate values and initialises the species values
for the entire domain. Also, for the two wall face-zones WALLSIDE1
and WALLSIDE2 (one of which is the shadow of the other), it works
out pairs of cells on either side of each face.
*/

/* Here is the initialisation of the UDM & species: */
thread_loop_c(tc1,d)
{
begin_c_loop(c1,tc1)
{
C_UDMI(c1,tc1,UDM_NEIGHBOUR_C) = 0.0;
C_UDMI(c1,tc1,UDM_NEIGHBOUR_TC) = 0.0;
C_UDMI(c1,tc1,UDM_MASS_SOURCE) = 0.0;
}
end_c_loop(c1,tc1)
}

/* Here is the pairing of cells: */

/* First, find the threads of the two wall face-zones: */
tf1 = Lookup_Thread(d,WALLSIDE1);
tf2 = Lookup_Thread(d,WALLSIDE2);

/* Loop through all faces on one of the face-zones: */
begin_f_loop(f1,tf1)
{
/* Find the centroid of this face: */
F_CENTROID(f_c1,f1,tf1);

/* Find the cell linked to this face: */
c1 = F_C0(f1,tf1);
tc1 = THREAD_T0(tf1);

/* Loop through all faces of the other face-zone: */
begin_f_loop(f2,tf2)
{
/* Find the face with the same centroid, to within
TOLERANCE. TOLERANCE should therefore be a distance
smaller than the size of a cell (but not too much
smaller, to avoid missed pairings due to round-off). */
F_CENTROID(f_c2,f2,tf2);
if (fabs(f_c1[0]-f_c2[0]) <= TOLERANCE &&
fabs(f_c1[1]-f_c2[1]) <= TOLERANCE &&
fabs(f_c1[2]-f_c2[2]) <= TOLERANCE )
{
/* Having found the matching face, find its cell: */
c2 = F_C0(f2,tf2);
tc2 = THREAD_T0(tf2);

/* Note each cell's partner in the User-Defined Memory.
UDMs must record real values -- add 0.1 so that an
integer is not recorded as x.9999999 as the nearest
real. */
C_UDMI(c1,tc1,UDM_NEIGHBOUR_C) = c2 + 0.1;
C_UDMI(c2,tc2,UDM_NEIGHBOUR_C) = c1 + 0.1;
C_UDMI(c1,tc1,UDM_NEIGHBOUR_TC) = THREAD_ID(tc2) + 0.1;
C_UDMI(c2,tc2,UDM_NEIGHBOUR_TC) = THREAD_ID(tc1) + 0.1;
}
}
end_f_loop(f2,tf2)
}
end_f_loop(f1,tf1)
MY_PRINT("\n Membrane initialisation completed.\n");
}
DEFINE_SOURCE(source_mass,c,t,ds,eqn)
{
/* This source term should be applied to the entire
* fluid zone (because it is zero where not needed),
* as both a mass source and a species source. */
ds[eqn] = 0.0;
return C_UDMI(c,t,UDM_MASS_SOURCE);
}

Thanks in advance.

[vinerm]

Check it in Serial first. I hope you are compiling it because it will not work as Interpreted code. If it works in Serial, then parallelization could be done. However, if you get some error in Serial mode, then parallelization may still be required, but only after the other issues have been resolved. And if you get an error during Serial Compilation or execute, please copy the whole error message.

[rajeev2111]

Originally Posted by vinerm

Check it in Serial first. I hope you are compiling it because it will not work as Interpreted code. If it works in Serial, then parallelization could be done. However, if you get some error in Serial mode, then parallelization may still be required, but only after the other issues have been resolved. And if you get an error during Serial Compilation or execute, please copy the whole error message.

Hi Vinerm,

I don't know how to run this code in serial. I am using ANSYS 2020R1. I have compiled the UDF successfully and also hooked the function but the fluent is exiting abruptly after the initialization of the case. Please help me in this regard.


Thanks in advance.

[vinerm]

Start Fluent with -t0 as option.