Learning Forum

[fuad87]

Hello All,

I have written an UDF for my UDS. Now I need to use the gradient of that UDS to the momentum eqn as source. The problem is that the gradient of the UDS (C_UDSI_G(c,t,i)[j]) is not available when momentum equation is being solved unless I input "yes" to this “Keep temporary solver memory from being freed?”. But keeping memory is not available in parallel, hence I can use my code only in serial. How can I store the gradient of the UDS and use it as source to the momentum in parallel? TIA

[DrAmine]

Which release are you using? 

[fuad87]

I am using 17.2 academic 

[DrAmine]

Hi,

With the documented way to obtain gradients (via Keep temporary solver memory from being freed? yes) I am able to obtain gradient for my UDS in parallel (R19.1).

[fuad87]

I couldn't do it in parallel. I don't know why. So tried this, but an error saying "Scalar_Reconstruction" is undefined variable. 

 

DEFINE_ADJUST(my_adjust,d)

{

#if !RP_HOST

int n;

int phase_domain_index = 0;  /*primary phase index is 0 */

Domain *domain;

        cell_t c;

        Thread *t;

Thread *liq; 

        domain = DOMAIN_SUB_DOMAIN(d,phase_domain_index); 

 

for (n=0; n

{

MD_Alloc_Storage_Vars(domain, SV_UDSI_RG(n), SV_UDSI_G(n), SV_NULL);

Scalar_Reconstruction(domain, SV_UDS_I(n), -1, SV_UDSI_RG(n), NULL);

Scalar_Derivatives(domain, SV_UDS_I(n), -1, SV_UDSI_G(n), SV_UDSI_RG(n), NULL);

}

 

    thread_loop_c (t,d)

{

liq = THREAD_SUB_THREAD(t,phase_domain_index);

begin_c_loop (c,t)

{

C_UDMI(c,t,0) = C_UDSI_G(c,liq,0)[0];

C_UDMI(c,t,1) = C_UDSI_G(c,liq,1)[0];

C_UDMI(c,t,2) = C_UDSI_G(c,liq,1)[1];

C_UDMI(c,t,3) = C_UDSI_G(c,liq,2)[1];

}

end_c_loop (c,t)

    }

#endif

 }

[DrAmine]

The documented approach is working for me in parallel. The approach you are posting is not documented and not supported. Anyway I managed to have gradients based on that approach. Alloc_Storage_Vars is the right function at first. Please help your self by writing debugging messages as they helped me actually to debug the errors.