[antoheb]

Hello everyone,

I wanted to apply Lorenz force (electric part only) on discrete particles. So I calculated a potential field as a UDS, which seemed OK. Next step was about making a UDF which calculates gradient of scalar and use it as an electric field. There came the problem.

UDF was built and loaded without any errors, UDMI was defined manually using GUI, but when I tried to run calculations, it did 1 iteration then boom and SIGSEGV (pic below). Tried to google it - didnt help. I think i'm wrong with allocating, but i dont know how to do it instead.

When i try to get to my UDS_G in code it comes to me with SIGSEGV.



code:

#include "udf.h"
#include "sg.h"
#define Q 0.00000000000054 /* particle electric charge */
#define TSTART 0.0 /* field applied at t = tstart */

DEFINE_ADJUST(setudmi,d)
{
   Thread *t;
   cell_t c;
   int n;

    /*/Calculating Vorticity Derivatives*/
   for (n=0; n<n_uds; n++)
   {
      uds_derivatives(d,n);
   }

   if (NULL != THREAD_STORAGE(t,SV_UDS_I(0) ) &&
   NULL != T_STORAGE_R_NV(t,SV_UDSI_G(0)))

   thread_loop_c(t,d)
   {
      begin_c_loop(c,t)
         {
            C_UDMI(c,t,0) = C_UDSI_G(c,t,0)[0];
            C_UDMI(c,t,1) = C_UDSI_G(c,t,0)[1];
         }
      end_c_loop(c,t)
   }
}

void uds_derivatives(Domain *d, int n)
{
   /* Code to compute derivative of a variable.  Variable storage allocation first.... */
   MD_Alloc_Storage_Vars(d, SV_UDSI_RG(n), SV_UDSI_G(n), SV_NULL);
   Scalar_Reconstruction(d, SV_UDS_I(n), -1, SV_UDSI_RG(n), NULL);
   Scalar_Derivatives(d, SV_UDS_I(n), -1, SV_UDSI_G(n), SV_UDSI_RG(n), NULL);
   return;
}

DEFINE_DPM_BODY_FORCE(lorenz,p,i)
{
   Thread *t = P_CELL_THREAD(p);
   cell_t c = P_CELL(p);
   real bforce;
   real e_x, e_y;

   e_x = C_UDMI(c,t,0); /* 1000000; /* C_UDSI_G(c,t,0)[0]; */
   e_y = C_UDMI(c,t,1); /* 1000000; /* C_UDSI_G(c,t,0)[1]; */
   
   if(P_TIME(p)>=TSTART)
      {
         if(i==0) bforce=-Q*e_x;/*C_UDMI(c,t,0);*/
         else if(i==1) bforce=-Q*e_y;/*C_UDMI(c,t,1);*/
      }
   else
      {
         bforce=0.0;
      }
   return (bforce/P_MASS(p));
}

Shortly, when i run it with E_x = *number* it works fine. But i want it to go E_x = C_UDSI_G[0] (etc.) somehow

thanks!
p.s. my first one, pls don't judge...

[antoheb]

Originally Posted by antoheb

Hello everyone

problem solved, thanks

[telegrampay.eth]

Originally Posted by antoheb

problem solved, thanks

how did you solve it?

[mary24]

Hi, may I know how do you solve it?