[Pmaroul]

Hello all;

How can we save a written vector(array) (for example 2*30 ) and read (use) it for other or same UDF macros in the next time step or iterations?

Thanks a lot for any advice.

P.Maroul

[Pmaroul]

Maybe I couldn't ask my question clearly, therefore I try to re-raise my question with a Pseudocode .

#include udf.h
for(int i=0;i<n0;i++)
for(int j=0;j<m0;j++)
A(i,j)= A(i,j)+ /*some modifications or updates*/

DEFINE_ADJUST(my_adjust,d)
{
.
.
.

/*some written text codes*/
.
.

}

Is the updating of this array(A(i,j) ) possible or this quantity re-initialized to zero in every iteration?

[AlexanderZ]

#include udf.h
int n,m,i;
real **A;
A= (real**)malloc((m)*sizeof(real*));
for (i=0; i<m; i++)
		{
			A[i] = (real*)malloc(n*sizeof(real));
		}

you may use this array everywhere and update whenever you want

best regards

[Pmaroul]

Originally Posted by AlexanderZ

#include udf.h
int n,m,i;
real **A;
A= (real**)malloc((m)*sizeof(real*));
for (i=0; i<m; i++)
		{
			A[i] = (real*)malloc(n*sizeof(real));
		}

you may use this array everywhere and update whenever you want

best regards

Thanks sir so much.

How about two-dimensional arrays?
Is the following Pseudocode right?

#include udf.h
int n,m,i;
real **A;
A= (real**)malloc((m)*sizeof(real*));
for (j=0; j<m; j++)
{
for (i=0; i<n; i++)
		{
			A[i][j] = (real*)malloc(n*sizeof(real));
		}}

Moreover, is the file printing a good idea(For example , rewriting a new matrix in the file and its reading for the next iteration ) specially if matrix (array) post-processing is to be important for us in any time step?

[pakk]

No, your code is not correct.


See for example here how to correctly allocate a 2D array in c.

[AlexanderZ]

I gave you code for memory allocation for 2D array (matrix)
than you may define value of each element in matrix using 2 loops for i and j

you may do whatever you want. but reading/writing to file may take some time, depends on the size of your matrix. play with it.

reading/writing to file functions are different for single core computation and parallel approach, take it into account

best regards

[Pmaroul]

Thanks Sirs very much !

If you're not in a hurry, can you send a Pseudocode executing the matrix's printing(A[i,j]) in a file, for example, in intervals of every ten time steps, and then from which part of the FLUENT options, the output of this matrix is visible?

for example for a 2D array , how can I plot A[i][1] versus A[i][2] in each 10 deltaT in Fluent or other post processing tools?

Thanks in advance for any help.

[Pmaroul]

Originally Posted by AlexanderZ

I gave you code for memory allocation for 2D array (matrix)
than you may define value of each element in matrix using 2 loops for i and j

you may do whatever you want. but reading/writing to file may take some time, depends on the size of your matrix. play with it.

reading/writing to file functions are different for single core computation and parallel approach, take it into account

best regards

Dear Alexander.

Are the n, m constant parameters dynamic allocated in udf's , too?

[Pmaroul]

Originally Posted by AlexanderZ

#include udf.h
int n,m,i;
real **A;
A= (real**)malloc((m)*sizeof(real*));  /*command line4*/
for (i=0; i<m; i++)
		{
			A[i] = (real*)malloc(n*sizeof(real));
		}

you may use this array everywhere and update whenever you want

best regards

Dear Alexander

I compiled your suggested sub-code and encountered below error:

error C2040: 'A' : 'int ' differs in levels of indirection from 'double ** ' for the command line 4:"A= (real**)malloc((m)*sizeof(real*));"

How can I resolve this error?

[AlexanderZ]

#include "udf.h"
int n = 10,m =10;
real **A;

DEFINE_ON_DEMAND(Allocate_memory)
{
int i,j;
A= (real**)malloc((m)*sizeof(real*));
for (i=0; i<m; i++)
		{
			A[i] = (real*)malloc(n*sizeof(real));
		}
}

DEFINE_ON_DEMAND(Define_matrix)
{
	int i,j;
	for (j=0; j<m; j++)
	{	for (i=0; i<n; i++)
		{
			A[i][j] = i+j;
		}
	}
}

DEFINE_ON_DEMAND(Free_memory)
{
	free(A);
}

best regards

[Pmaroul]

Dear Alexander.

Your answer was so helpful!!. Really I had to define that array in a define-on-demand and then to update in other macros.

Good luck and best wish for you.