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ehooi May 12, 2011 09:45
UDF issues
 
Hi all,
I am having some problems with UDF. Basically I have written a UDF which worked well before and now that I have developed a new model, when I use the same UDF, it gives me problems.

The UDF is as follows:

PHP Code:
#include "udf.h"
DEFINE_ADJUST(fcn_outlet,d)
{
/* -------------------------------------------------------------------------*/ 
#if !RP_HOST    /*  either serial or compute node process is involved */
/* Variable Declaration */
 
 double Tout = 0.0;
 double Tin;
 double Ttemp;
 double C1, C2;
 double coord[ND_ND];
 double xxmin = 0.27; 
 double xxmax = 0.28;
 double yymin = -0.012;
 double yymax = -0.007;
 double zzmin = -0.68;
 double zzmax = -0.66;
 double xx,yy,zz;
 double nd = 0.0;
 double hamb = 10.0;
 double area1 = 0.0416;
 double area2 = 0.0649;
 double mtot = 0.174;
 double mind = 0.0435;
 double cp = 2470.0;
 double Tamb = 300.9;
 double L1 = 0.5757;
 double L2 = 1.08955;
 
 int i;
 int ID_tank = 30;
 int ID_out = 68; 
 int ID_back1 = 66; 
 int ID_back2 = 67; 
 int ID_front1 = 60; 
 int ID_front2 = 61; 
 int ID_left1 = 64; 
 int ID_left2 = 65; 
 int ID_right1 = 62; 
 int ID_right2 = 63;
 cell_t c;
 face_t f;
 Thread *thtank;
 Thread *thout;
 Thread *thb1;
 Thread *thb2;
 Thread *thf1;
 Thread *thf2;
 Thread *thl1;
 Thread *thl2;
 Thread *thr1;
 Thread *thr2;
 thtank = Lookup_Thread(d, ID_tank);
 thout = Lookup_Thread(d, ID_out);
 thb1 = Lookup_Thread(d, ID_back1);
 thb2 = Lookup_Thread(d, ID_back2);
 thf1 = Lookup_Thread(d, ID_front1);
 thf2 = Lookup_Thread(d, ID_front2);
 thl1 = Lookup_Thread(d, ID_left1);
 thl2 = Lookup_Thread(d, ID_left2);
 thr1 = Lookup_Thread(d, ID_right1);
 thr2 = Lookup_Thread(d, ID_right2);
/* -------------------------------------------------------------------------*/  
 /* Begin loop to calculate the temperature of cells surrounding outlet */
 /* Computation carried out on node 0 */
 if(I_AM_NODE_ZERO_P)
 {
 
  begin_c_loop(c,thtank)
  {
   C_CENTROID(coord,c,thtank);
   xx = coord[0];
   yy = coord[1];
   zz = coord[2];
   if ((xx >= xxmin) && (xx <= xxmax))
   {
    if ((yy >= yymin) && (yy <= yymax))
    {
     Message("ncell = %f\n", zz);
     if ((zz >= zzmin) && (zz <= zzmax))
     {        
      Tout = Tout + C_T(c,thtank); /* Cell temperature */
      nd = nd + 1.0;    /* Number of cells */
     }
    }
   }
  }
  end_c_loop(c,thtank)
  
  Tout = Tout/nd; /* Average cell temperature surrounding outlet */
  C1 = -hamb*area1*L1/(mtot*cp);
  Ttemp = (Tout-Tamb)*exp(C1) + Tamb;
  C2 = -hamb*area2*L2/(mind*cp);
  Tin = (Ttemp-Tamb)*exp(C2) + Tamb;
  Message("ncell = %f\n", nd);
  Message("Tout = %f\n", Tout);
  Message("Tin = %f\n", Tin);
  compute_node_loop_not_zero(i)
  {
   PRF_CSEND_DOUBLE(i, &Tout, 1, myid);
   PRF_CSEND_DOUBLE(i, &Tin, 1, myid);
  }
 }
 /* Reception of average temperature from node zero */
 if(! I_AM_NODE_ZERO_P)
 {
  PRF_CRECV_DOUBLE(0, &Tout, 1, 0);
  PRF_CRECV_DOUBLE(0, &Tin, 1, 0);
 }
 
/* -------------------------------------------------------------------------*/  
 /* Store calculated values in user-defined memory */
 /* Outlet */
 begin_f_loop(f, thout)
 {
  F_UDMI(f,thout,0) = Tout;
 }
 end_f_loop(f,thout)
 
 /* Back 1 */
 begin_f_loop(f, thb1)
 {
  F_UDMI(f,thb1,1) = Tin;
 }
 end_f_loop(f,thb1)
 /* Back 2 */
 begin_f_loop(f, thb2)
 {
  F_UDMI(f,thb2,2) = Tin;
 }
 end_f_loop(f,thb2)
 
 /* Front 1 */
 begin_f_loop(f, thf1)
 {
  F_UDMI(f,thf1,3) = Tin;
 }
 end_f_loop(f,thf1)
 
 /* Front 2 */
 begin_f_loop(f, thf2)
 {
  F_UDMI(f,thf2,4) = Tin;
 }
 end_f_loop(f,thf2)
 /* Left 1 */
 begin_f_loop(f, thl1)
 {
  F_UDMI(f,thl1,5) = Tin;
 }
 end_f_loop(f,thl1)
 /* Left 2 */
 begin_f_loop(f, thl2)
 {
  F_UDMI(f,thl2,6) = Tin;
 }
 end_f_loop(f,thl2)
 /* Right 1 */
 begin_f_loop(f, thr1)
 {
  F_UDMI(f,thr1,7) = Tin;
 }
 end_f_loop(f,thr1)
 
 /* Right 2 */
 begin_f_loop(f, thr2)
 {
  F_UDMI(f,thr2,8) = Tin;
 }
 end_f_loop(f,thr2)
#endif
}
/* -------------------------------------------------------------------------*/
 

DEFINE_PROFILE(temp_out,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,0);
  }
  end_f_loop(f,t)
 }
#endif
}

DEFINE_PROFILE(temp_back1,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,1);
  }
  end_f_loop(f,t)
 }
#endif
}

DEFINE_PROFILE(temp_back2,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,2);
  }
  end_f_loop(f,t)
 }
#endif
}
 
DEFINE_PROFILE(temp_front1,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,3);
  }
  end_f_loop(f,t)
 }
#endif
}
 
DEFINE_PROFILE(temp_front2,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,4);
  }
  end_f_loop(f,t)
 }
#endif
}
 
DEFINE_PROFILE(temp_left1,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,5);
  }
  end_f_loop(f,t)
 }
#endif
}
 
DEFINE_PROFILE(temp_left2,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,6);
  }
  end_f_loop(f,t)
 }
#endif
}

DEFINE_PROFILE(temp_right1,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,7);
  }
  end_f_loop(f,t)
 }
#endif
}
 
DEFINE_PROFILE(temp_right2,t,i)
{
#if !RP_HOST
 double flow_time = CURRENT_TIME;
 face_t f;
 if (flow_time <= 601.0)
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = 333.0;
  }
  end_f_loop(f,t)
 }
 else
 {
  begin_f_loop(f,t)
  {
   F_PROFILE(f,t,i) = F_UDMI(f,t,8);
  }
  end_f_loop(f,t)
 }
#endif
} 
The UDF basically calculates the average of temperature at a certain location to be input as the temperature elsewhere (something like a recirculation system where the temperature at the outlet is the same as the temperature at the inlet.

The problem now is that this part the cells are not within the limits set. In other words, in this section:
if ((xx >= xxmin) && (xx <= xxmax))
{
if ((yy >= yymin) && (yy <= yymax))
{
Message("zz = %f\n", zz);
if ((zz >= zzmin) && (zz <= zzmax))

when I print out the values of zz after xx and yy, they are not within the zzmin and zzmax limit, hence I get a division by zero.

There are definitely cells within the z limit. Anyone knows why this is happening?

Thanks and I really appreciate any help.

Sincerely,
EH

coglione May 13, 2011 03:49
I think the problem is that the grid partition belonging to node-0 does not include all (or even any) cells of this cell_thread "thtank". Hence some or all cells actually within your limits simply can not be found by this node. If so, then running in serial should give correct results. Check this.

cheers

ehooi May 13, 2011 04:42
Hi,
Thank you. I think this may be the reason why I am not getting the limits. Unfortunately I have to run it in parallel since this is a very large problem. However, I thought node-0 is the node that stores all the coordinates. Is this correct?

Thanks,
EH



Quote:
Originally Posted by coglione (Post 307471)
I think the problem is that the grid partition belonging to node-0 does not include all (or even any) cells of this cell_thread "thtank". Hence some or all cells actually within your limits simply can not be found by this node. If so, then running in serial should give correct results. Check this.

cheers

ehooi May 13, 2011 05:18
Hi again,
I tried reversing the code to compute the temperature at all the non-zero nodes i.e. by using

IF (! I AM NODE ZERO)

After computation, I need to pass the result to node zero. Usually we compute everything in node zero and pass it to nonzero nodes. Is it possible to pass values from non zero nodes to node zero, ie something like this:

compute_node_loop_zero(i)
{
PRF_CSEND_DOUBLE(i, &Tout, 1, myid);
PRF_CSEND_DOUBLE(i, &Tin, 1, myid);
}
}
/* Reception of average temperature from node zero */
if(I_AM_NODE_ZERO_P)
{
PRF_CRECV_DOUBLE(0, &Tout, 1, 0);
PRF_CRECV_DOUBLE(0, &Tin, 1, 0);
}

Any help is really appreciated

Thanks,

EH


Quote:
Originally Posted by coglione (Post 307471)
I think the problem is that the grid partition belonging to node-0 does not include all (or even any) cells of this cell_thread "thtank". Hence some or all cells actually within your limits simply can not be found by this node. If so, then running in serial should give correct results. Check this.

cheers

coglione May 13, 2011 05:21
No, as far as I know every node has full information about everything but also only in its partition. The only special thing with node-0 is that he is in charge for communication with host.
Thus in general every node has to perform the desired actions on its own and then a global summation has to be done. See section 7.5.4 in the udf manual how this works.

cheers


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